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Procedure for maintenance of electrical installations. Manual - Operation of electrical equipment of power supply systems - file n1.doc
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n1.doc
Operation of electrical equipment of SES: Program, guidelines and control tasks/.- Kurgan: KSU, 2006-11-16-22p.Issues of organization and installation technology of electrical equipment 0.4...220 kV are outlined industrial enterprises, problems of adjustment and testing of electrical installations. The issues of operation of electrical installations are presented: overhead and cable lines, switchgears, transformers, etc., as well as the tasks of supervision and organization of repairs of these installations. Questions regarding the operational maintenance of electrical installations of enterprises are formulated.
Guidelines for studying sections of the program and test assignments are provided.
The program and guidelines are compiled in accordance with the curriculum of the course "Operation of SES electrical equipment" for full-time and part-time students of the specialty "Electrical supply"
Il. 4, table. 3, list of lit. - 8 titles
PROGRAM AND METHODOLOGICAL INSTRUCTIONS FOR STUDYING THE COURSE
I. General issues of installation and commissioning of electrical equipment
The purpose and objectives of the course "Operation of electrical equipment of SES".
Electrical installation work, structure of electrical installation organizations in the USSR. The basic principles of electrical installation work: large-block construction, industrialization, mechanization and scientific organization. Stages (stages) of electrical installation work.
Commissioning works, content and organization of work, their volume. Instruments and equipment for commissioning and testing. General provisions for acceptance of electrical equipment by the customer.
Marking of electrical installations, devices, electrical circuits(GOST 2.709-72). Marking technique.
Basic regulatory documents: rules, regulations, technological instructions, manuals regulating the design, installation and commissioning of electrical installations. Rules for the construction of electrical installations (PUE). .
Guidelines
When studying the material, take into account that electrical installation work (EMW) at industrial enterprises (except for the subordination of the Ministry of Energy and the Ministry of Railways) is carried out by organizations of the USSR Ministry of Installation and Special Construction (trusts, departments). This ministry also includes design institutes (VNIIPEM, TPEP) and factories of electrical installation structures.
Reveal the content of each of the principles of EMR implementation, in particular, show that the degree of industrialization can be defined as the ratio of the cost of work performed outside the installation site to the total cost of work: Kind=Smzu/Semr. Pay attention to the technical need to perform EMR in three stages: assembly of large blocks of electrical equipment, testing, adjustment outside the installation area, preparatory work at the site and the actual installation of the electrical installation.
It is necessary to understand at what specific stage of the EMR and installation of an electrical installation it falls under the scope of PTE and PTB.
When studying the procedure for marking electrical installations, it should be taken into account that GOST applies to electrical circuits and devices, and the marking of switchgear cells, transformer substations, etc. is carried out based on ease of setup and operation.
2. General issues of technical operation
Electrical installations
Requirements for the operation of electrical installations. The concept and meaning of operation as applied to electrical equipment. Participation of various organizations in operation.
Scheduled preventive maintenance of electrical equipment (PNR). The purpose and objectives of PPR, the concept of physical wear and tear of parts and components of electrical equipment, reversible and irreversible changes in parameters, determination of the degree of physical wear. Absolute and relative standardization of electrical installation parameters.
Purpose and scope of overhaul inspection, current and major repairs. The procedure for carrying out major repairs. Technical documentation for the operation of electrical installations.
Fundamentals of technical diagnostics of faults in electrical installations. Techniques for detecting faults in electrical equipment and electrical circuits. Diagnostic devices, measures for safe organization of work.
Work order for work on electrical installations, responsibility of persons for the safety of work. Carrying out work as ordered, in the order of routine operation.
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Guidelines
When studying the material, it is necessary to understand the types of physical wear of electrical equipment: types of mechanical, electrical, and thermal wear. Absolute standardization of technical parameters of equipment consists in establishing a specific indicator or resource (resistance of the suspension insulator is at least 300 MOhm, number of switch operation cycles 2*, etc.). Relative evaluation consists of comparing performance data with the results of previous factory or commissioning tests.
Pay attention to the frequency and patterns of alternating between repair inspections, current and major repairs. In technical diagnostics, know the difference between functional and test diagnostics (according to GOST 20.911-75), types of input influences, and formulation of tasks.
When studying the rules for carrying out work in existing electrical installations according to order, by order, in the order of routine operation, use.
3. Operation and installation of overhead lines
Power transmission
Basic definitions and general provisions for the construction of overhead lines (OHL). Documentation for the construction of overhead lines with voltages above 1 kV: design, route plan, longitudinal profile of the route, log of support layout, list of transitions, drawings of support foundations, work plan.
Overhead line installation technology. Preparatory work: production picketing, layout of installation sites for foundations for supports. Installation of individual elements of overhead lines: prefabricated reinforced concrete foundations, grounding of supports. Methods for installing supports, identifying defects in reinforced concrete and wooden supports. Assembling garlands, rejecting insulators. Installation of wires and lightning protection cables, securing wires to supports. Determination of the sag of wires and cables, installation tables and graphs, tension force of wires and cables.
Mechanical loads on overhead lines, zoning of the territory of the USSR according to wind load and ice, the concept of wind pressure. Loads from your own weight, ice and wind. Vibration of wires, causes of vibration, measures to eliminate vibration, dancing of wires.
Acceptance documentation, scope of acceptance inspections, inspections and tests. Measuring the sag of wires in spans and at intersections.
Walk-throughs and inspections of overhead lines during operation, extraordinary inspections. Monitoring the integrity of insulators on an operating overhead line. Methods for removing ice from wires. Operation of auxiliary structures of overhead lines.
Electrical overloads of overhead lines under operating conditions. Current and major repairs of overhead lines, scope of repairs, revision and testing of tubular arresters.
Overhead power lines with voltage up to I kV.
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Guidelines
Before studying the material, you should repeat the general information about supports, wires, insulators and other structural elements of overhead lines. In the section being studied, learn how to install supports: using a crane, the falling boom method, using a helicopter. Know the calculation of forces generated when using the falling arrow method. Pay attention to how the mounting tables (mounting curves) connect the sag boom to each other f, temperature environment?, span length l p, permissible mechanical stresses in the wires.
When studying the influence of climatic and meteorological conditions on overhead lines, understand the procedure for determining the wind speed pressure and the additional vertical load from ice on wires and supports. Find out which region the Chelyabinsk region belongs to in terms of wind load and ice.
Please note that electrical overloads of overhead line wires depend on the type of wire, air temperature and permissible temperature of the wire, and wind speed. The corresponding nomograms are given and the procedure for using them is shown.
4. Operation and installation of cable lines
Brief information about brands and designs power cables voltage up to 110 kV. General provisions of the PUE and SNiP for the construction of cable lines: selection of the cable line route, security zone, designation of cable laying methods on the master plans of enterprises.
Selecting a cable brand depending on the installation conditions. Laying methods: in earthen trenches, in concrete patches, trays, channels. Laying in cable rooms: tunnels and collectors. Special types of laying: through water barriers, over bridges and overpasses. Combination of cable routing methods. Laying cables at low ambient temperatures; methods for heating cables. Crossing and approaching cable lines with engineering weapons.
Cable couplings and terminations, their purpose and classification. PUE requirements for couplings and seals.
Protection against corrosion of metal sheaths of cables laid in the ground.
Scope and standards of acceptance and preventive testing of cable lines; acceptance documentation. Operating conditions of cable lines.
Operation of cable lines, inspections of routes and cables. Monitoring the heating and condition of cable insulation, the level of stray currents on the cable line route. Insulation monitoring under operating voltage.
Determination of the nature of damage to cable lines, types of damage. Burning the damaged area of the cable line. Damage table and diagrams. Methods for determining locations of damaged cable insulation or broken cable cores.
Organization of cable line repair, repair technology, safety measures when repairing cable lines.
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Guidelines
You should begin studying this section by repeating the material about the designs and brands of power and control cables with voltages up to and above I kV. Next, you should systematize the laying conditions: the difference in levels along the length of the cable line, the presence of mechanical influences during installation and operation, the presence of tensile forces, constant movements of the cable, temperature conditions, fire hazard, explosive environment, corrosiveness of the soil, and relate this to the choice of cable brand.
Please note that the PUE limits the number of couplings per cable line, know the permissible number of couplings and measures to reduce this number, for example, by switching to single-core cables.
Promising in operation is monitoring the insulation of a cable under operating voltage. Understand the connection diagram of the kenotron installation during such a test, determine the level of pulsating voltage.
When considering methods for determining nature of damage CL should not be confused with methods for determining places of damage, who have different tasks and devices used. Pay attention to safety precautions when servicing, repairing and operating cable lines.
5. Operation and installation of complete conductors
Voltage up to 35 kV and busbars
Basic provisions and definitions for conductors. Types and designs of rigid complete and flexible conductors. Open and closed conductors, nomenclature of sections, installation requirements. Closed complete conductors of 10 kV transformers of the main step-down substations.
Acceptance tests and documentation, operation of conductors.
Busbars up to I kV; types and designs of main, distribution, trolley and lighting busbars. Nomenclature and purpose of individual sections of the busbar, installation procedure. Testing and operation of busbar trunking.
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Guidelines
Please note that the range of sections of complete busbars is constantly expanding; In addition to straight sections, corner sections, connection units for switchgear, and transformer substation. Current conductors have been developed to connect the terminals of a 10 kV enterprise transformer with a closed switchgear.
Symmetrical current conductors have lower active and inductive resistance and lower energy losses. It should be noted that conductors are susceptible to damage during nuclear explosions compared to cable communications.
When studying 0.4 kV busbars, it should be noted that there are a greater number of varieties of sections of main busbars compared to distribution ones.
6. Operation and installation of workshop electrical equipment
Substations and switchgears
Requirements of PUE and SNiP for the construction of closed switchgears (RU). Standardization of the construction part of the reactor plant. Stages of electrical installation work. Distances from non-insulated live parts to elements of other equipment. Docking of cells of different types in one switchgear. Installation of switchgear buses, methods of forming contacts, colors of buses.
Testing of reactor plant equipment. Operation of the reactor plant: inspections, checking the heating of contact connections. Repair of switches with voltage 6-10 kV. Features of complete outdoor switchgear.
Installation of current-limiting reactors with a voltage of 610 kV, vertical, horizontal, stepped installations. Drying reactors, checking the quality of insulation. Repair and operation of concrete reactors.
PUE requirements for the construction of workshop transformer substations; open and closed installation; power of transformers; arrangement of oil receivers; ventilation, placement of complete transformer substations (CTS) and workshop.
Installation of package transformer substations, installation stages. Checking the transformer and switchgear voltage 0.4-0.66 kV before switching on.
Operation of package transformer substations, inspections, permissible overloads of transformers. Features of servicing transformers of furnace and converter substations, outdoor package transformer stations.
Operation and installation of grounding arc suppression reactors.
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Guidelines
On the issue of distances from live parts to various elements of the switchgear, you should only know their nomenclature: between wires of different phases, to permanent internal fences - without memorizing digital material. Show that the list given in the table exhausts all possible distance options.
It is allowed to use cells of different series in one switchgear; the design of their joints is given in the technical information of Tyazhpromelektroproekt.
For current-limiting reactors, you should know their markings. The main insulation of the reactors is formed by support insulators. Drying is carried out for interturn insulation, which covers concrete columns (drying oil, asphalt varnish). At the end of drying, the resistance Riz should not differ by more than 30% from the factory test data, but not less than I MOhm at a temperature of + 70°C. The preferred heating method for drying reactors is induction.
With regard to grounding reactors, it is necessary to understand what they have in common (in design) with power transformers. Similarly, they are divided into reactors for indoor and outdoor installation. The list of tests for transformers and grounding reactors is the same.
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7. Installation and operation of devices and busbars
Substations 35...220 kV
PUE requirements for the construction of 35-220 kV substations. Layout of the territory of an open switchgear (OSD), installation of fencing, overall dimensions of live parts.
Installation and testing of separators and their drives, installation and operation of disconnectors. Short circuiters and their drives, installation procedure. Scope of testing of short circuiters.
PUE requirements for the installation of power switches; assembly of switches and the procedure for their installation. Scope and standards of inspections and tests of switches, drives. The procedure for testing switches by repeatedly turning them on and off. Repair of switches with voltage 35...220 kV.
Installation of the substation outdoor switchgear busbar. Flexible and rigid busbars, clamps, features of their connection to devices. Checking the flexible busbar for absence of snapping during short circuits.
Requirements for the construction of closed switchgear 35...220 kV. Features of the use of oil-filled devices.
Features of installation and operation of substation devices with gas insulation. Safety precautions when working with SF6 devices.
Installation of block substations of types KTPB-35 and KTPB-110.
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Guidelines
Pay attention to the design features of the wire lugs that are connected to the outdoor switchgear devices. The tips are made of composite aluminum and copper parts by diffusion welding.
Particular attention should be paid to the issue of testing and inspection of oil circuit breakers 35...220 kV. Be able to decipher the vibration diagram of the switch and use it to construct the dependence of the speed of movement of the contacts on the stroke of the traverse: V= S / t*10i, Where S– distance between adjacent vertices of the vibrogram (mm); t= 0.01 s – time between vertices (vibrogram period).
When considering short circuiters, take into account that they are mounted on additional support insulators in order to be able to use the grounding busbar as the primary winding of the TSP current transformer. In this case, the number of primary ampere turns must be at least 500...800.
8.Installation and operation of power transformers
Groups of transformers according to transportation conditions, dismantled units for each group. Transportation, loading and unloading of transformers. Regulations.
Storage of transformers that arrived assembled or have dismantled components; checking transformers during storage at a warehouse site, leakage control.
Inspection of transformers with lifting of the removable part at different temperatures and air humidity. Scope of revision work with lifting of the removable part.
Indicators and assessment of the possibility of switching on newly commissioned transformers without drying. Transformers are divided into 5 groups according to evaluation criteria.
Drying of power transformers using the method of induction losses in the steel of the tank, zero sequence currents, other drying methods. Drying mode; vacuum drying and its control.
Technology for installing transformers that arrived assembled and disassembled, checking dismantled components before installing them on transformers.
Installation of the transformer on the foundation, rigging equipment. Oil receivers and transformer oil drainage. Fire prevention measures at the substation.
Transformer testing: scope and standards, devices used. The procedure for putting the transformer into operation. Load and temperature control, transformer overload. Inspections and maintenance of transformers, extraordinary inspections. Transformer insulation and its operation.
Conditions for immediate removal of a transformer from operation, characteristic malfunctions of transformers, their causes and symptoms. Serviceability analysis using gas chromatography methods.
Current and major repairs of transformers; volume, preparation, testing after repair.
Transformer oil and its operation, complete and abbreviated oil analysis. Transformers. Measures to protect the environment during the operation of oil-filled devices.
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Guidelines
It is necessary to get an idea of the criteria for assessing the condition of a transformer before turning it on. These are: the oil level in the transformer; testing an oil sample from a transformer in the scope of an abbreviated analysis and measuring tg?; measurement of insulation resistance Rvo"" and determination of the ratio R6о""/R15""; tg measurement? or C2\C50 windings in oil; determination of the ratio?C/C at the beginning and end of work during which the active part was in contact with air (before filling the transformer with oil); checking the condition of the indicator silica gel and the breakdown voltage of the oil from the bottom of the tank. For each group of transformers there is its own set of indicators (from those listed), subject to which it can be turned on without drying.
Transformer tests are divided into acceptance and preventive tests. You should study the points that are usually included in the test program, navigate the measurement schemes and be able to evaluate the test results. It is necessary to record the types of devices used for testing, the temperature of the windings, oil, etc., which will be required to compare the results of subsequent tests.
9. Electrical measurements and insulation tests
Electrical equipment
Electrical insulation equivalent circuit, geometric capacitance, absorption capacitance. Dependence of insulation resistance on temperature, humidity, and contamination.
Methods for measuring insulation quality indicators on DC. Absorption coefficient, the dependence of insulation quality on temperature and duration of voltage application. Direct current measuring instruments. Electronic megohmmeters.
Methods for measuring the insulation state on alternating current: determination of tg?, capacitive methods (C2\C50; ?C/C, etc.), dependence of measurement results on various factors. AC insulation testers.
Insulation test increased voltage alternating and rectified current, purpose of testing. Apparatuses and mobile testing units. Testing procedure, safety measures.
Insulation test with operating voltage ( alternating current) electrical installations. Testing using a partial discharge indicator and the scope of this method.
The procedure for testing the insulation of lines, devices, electrical machines.
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Methodical instructions.
Please note that a parallel insulation equivalent circuit is more convenient for explaining electrical phenomena and the constituent elements of the circuit; geometric capacitance, leakage resistance, resistance and absorption capacity. Determination of insulation resistance R6о"", absorption coefficient R6о"/R15"" should be carried out at a temperature of at least 10°C to eliminate errors from the phase state of water.
To compare the measurement results R6о"", R6о"", they should be reduced (recalculated) to the temperature of factory (commissioning) tests. You should know that the insulation resistance decreases with increasing temperature, and tg? -increases. The corresponding tables and conversion factors are available in PTE and PTB.
Please note that among the capacitive methods, C2\C50, ?C/C are mainly used, and the capacitance-temperature method is almost rarely used, for example, for power transformers.
Insulation testing with increased AC voltage is the main criterion on the basis of which a decision is made to put the installation into operation. An increase in the test voltage to 0.3Uisp is allowed abruptly, then no faster than 1...2 kV/s.
10. Operational maintenance of electrical installations
Operational maintenance and operational management of electrical equipment. Operational control points.
Operational restrictions on disconnecting circuits by disconnectors, power plug connectors, separators, load switches. Blocking from incorrect actions of operating personnel, Application of computers to control the correctness of switching in electrical installation circuits.
Emergency training for operational dispatch personnel. Use of microprocessors and computers to simulate emergency situations and control switching.
Guidelines
In the process of studying the material, it is necessary to understand the content of the concept of “operational maintenance” and the importance of operational management in the operation of electrical equipment. Be able to fill out a form for switching for repair of a transformer of the main step-down substation, sectional switch, separate connection - using the example of the power supply diagram of the course project.
Know what can be turned off and on with a disconnector (10 kV): magnetizing current of transformers with a power of up to 750 kV*A inclusive, ground fault current of overhead and cable lines, etc.
Pay attention to the use of simulators to develop the skills of operational switching in emergency situations. Present the procedure for using a computer to control switching.
CONTROL TASKS
When performing a control task you must:
I. State answers to questions clearly and comprehensively, provide explanatory diagrams, drawings (sketches), tables, graphs, use work order forms for switching operations.
2. Draw diagrams, sketches, layouts, structures, etc. using a ruler in compliance with the established ESKD images of circuit elements.
3. Construct graphs on graph paper in compliance with scale; Designate dimensions in compliance with GOST.
4. Summarize all similar calculations in problems into tables and provide calculation formulas and calculations for characteristic points in text. Individual calculation actions should be accompanied by concise, clear explanations.
5. It is necessary to complete tasks (except for the graphic part) in ink, in clear handwriting, leaving margins on the right side 2...3 cm wide.
6. On the title page of the assignment, indicate your last name, first name, patronymic, academic code, specialty and group number.
Selecting a control task option
The test task consists of three control questions and two tasks. The number of the test question option is selected according to the last digit of the student code: number I - option I; number 2 - option 2, ...., number 0 - option 10 in the following order:
| Task option | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| Question 1 | 1.1 | 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | 1.10 |
| Question 2 | 2.1 | 2.2 | 2.3 | 2.4 | 2.5 | 2.6 | 2.7 | 2.8 | 2.9 | 2.10 |
| Question 3 | 3.1 | 3.2 | 3.3 | 3.4 | 3.5 | 3.6 | 3.7 | 3.8 | 3.9 | 3.10 |
The choice of option of problem No. I and option of problem No. 2 is made according to the last two digits of the student’s code.
Question options 1
1.1. Inspection of overhead line supports before installation, methods of lifting and installing supports.
1.2. Rejection and testing of insulators, assembly of garlands, number of insulators in a garland, testing of insulators on an operating overhead line
1.3. Determination of tension and sag of wires. Installation tables (graphs)
1.4. Mechanical loads on overhead line wires and supports.
1.5. Documentation for acceptance of overhead lines into operation, scope of acceptance tests of overhead lines after installation.
1.6. Selecting a cable brand according to installation conditions.
1.7. Protection against corrosion of metal sheaths of cables laid in the ground.
1.8. Underwater cable laying, bridge laying.
1.9. Determining the nature of the cable damage and choosing a method for finding the location of the damage.
1.10. Testing cables after installation and major repairs.
Question options 2
2..1. Installation of disconnectors, short circuiters, separators. Tests after installation.
2.2. Testing of oil switches after installation.
2.3. PUE requirements for the construction and installation of open switchgear.
2.4. Requirements for armament and installation of open switchgear.
2.5. Installation of complete switchgear equipment. Tests after installation.
2.6. Installation of equipment for complete transformer substations. Tests after installation, maintenance during operation.
2.7.Installation of concrete reactors, overall distances. Drying of reactors, drying control.
2.8.Installation of conductors with voltage 10...35 kV. Commissioning tests.
2.9.Installation of trunk and distribution busbars. Inspection and testing after installation.
2.10. Operation of complete transformer substations.
Question option 3
3.1. Methods for determining the main characteristics of transformer insulation.
3.2. Drying of transformers using the method of induction losses in the steel tank. Vacuum drying.
3.3.Evaluation of the possibility of switching on transformers transported without oil without drying.
3.4.Evaluation of the possibility of switching on without drying transformers transported with removed mounted units, but filled with oil.
3.5.Evaluation of the possibility of switching on without drying transformers transported fully assembled and filled with oil.
3.6. Installation of power transformers at the outdoor switchgear of the main step-down substation.
3.7. Technology of filling and topping up transformer tanks with oil.
3.8. Requirements for transportation and storage of power transformers. Inspection of transformers with lifting of the removable part.
3.9. Installation and operation of grounding arc suppression reactors. Tests after installation.
3.10. Testing transformers before putting them into operation.
Variants of problem No. I
Options from 00 to 10. Figure I shows a vibration diagram for turning off the switch
Picture 1
Figure 2 Figure 3
Options II to 15. The interturn insulation resistance of the RBAS reactor was I MOhm at a temperature of 20°C. Determine if the reactor needs to be dried. Give a schematic diagram for measuring this insulation.
Options 1C to 20. Draw up a test program for indoor 10 kV concrete reactors. The reactor phases are arranged vertically (4, Fig. 3.14). Specify the equipment for testing.
Options 21 to 24. Draw up a test program for the KM2-0.38-75 capacitor. Provide diagrams, tests, indicate the devices used.
Options 25 to 45. Using the nomograms Fig. 2, Fig. 3, determine the possible overload (in amperes) of overhead power line wires. The operating conditions and brand of line wire are specified in the table.
| Options | 25...27 | 28...30 | 31...33 | 34...36 | 37...39 | 40...42 | 43...45 |
| Wire brand | AS-25 | AS-25 | AS-35 | AS-35 | AS-50 | AS-50 | AS-70 |
| Air temperature?в,єС | 0 | 20 | 40 | 0 | 20 | 40 | 20 |
| Wire temperature? | 70 | 80 | 90 | 70 | 80 | 90 | 70 |
| Wind speed V,m/s | 1 | 1.5 | 2 | 1 | 2 | 3 | 2 |
The sequence for determining the permissible gearbox overload factor is shown in the nomograms.
Options 46 to 54. Calculate heating power P (kW) and data ( S, sq.mm; N- number of turns) of the magnetizing winding for drying the power transformer using the induction loss method. Perform the calculation for the main substation transformer from the course project on power supply. Draw a diagram for connecting the magnetizing winding to the phases of the supply network, determine cos? .
Options 55 to 64. According to the factory test report of the transformer R6о"" = 450 MOhm at a temperature? = 60°C. Reduce these data to an installation temperature of 20°C.
Options 65 to 74. According to the transformer factory test report, tg?1 = 8.1% at a temperature of 60°C. Convert these data to an installation temperature of 20°C.
Options from 75 to 90. Make a list of works in electrical installations up to 1000 V of your enterprise (organization, workshop, department), which can be performed by electrical personnel in the order of routine operation. The list should be compiled in the form of an order from the chief power engineer.
Options 90 to 95. AAB brand cables 3x95 sq. mm in the amount of 50 pieces are laid in the tunnel, the load current is 100 A. Indicate the amount of heat generation per I m of the tunnel.
Options 95 to 99. The thermal power generated by APsPB cables 3x95 sq. mm (per 1 km of laying length) is 50 kW, the average load current is 100A. Determine the installation method.
Variants of task No. 2
It is required to draw up a work order based on the diagram (Fig. 4) or fill out a switching form in accordance with the task. Both bus sections and transformers are in operation, the section switch is turned off.
| Options | Exercise |
| 00...05 | Work order for cable line repair W1 |
| 06...10 | Form for switching to repair line W1 |
| 11...15 | Repair order for transformer T5 |
| 16...20 | Form for switching to repair output T5 |
| 21...25 | Repair order for line disconnector QS7 |
| 26...30 | Form for switching to output for repair of disconnector QS7 |
| 31...35 | Repair order for transformer T3 (TSN) |
| 36...40 | Form for switching to repair T3 (TSN) |
| 41...45 | Repair order for input switch Q1 |
| 46...50 | Switching form for repair output of switch Q1 |
| 51...55 | Work order for repair of 1st tire section |
| 56...60 | Form for switching to repair of the 1st bus section |
| 61...65 | Work order for repair of transformer T1 GPP |
| 66...70 | Form for switching to repair T1 GPP |
| 71...75 | Work order for repair of voltage transformer TV2 |
| 76...80 | Form for switching to repair TV2 |
| 81...85 | Repair order for sectional switch Q5 |
| 86...90 | Switching form for repair output of switch Q5 |
| 91...95 | Repair order for switch drive Q1 |
| 96...99 | Work order for repair of disconnector QS5 of transformer TV4 |
The disconnectors on both sides of the sectional switch are switched on in the normal circuit. Both auxiliary transformers (TSN) are in operation, the QF3 sectional machine is normally turned off. 
Fig.4
LITERATURE
1. Rules for the construction of electrical installations (PUE).-M.: Energoatomizdat, 1986,- 648 p.
2. Rules for the technical operation of consumer electrical installations and safety rules for the operation of consumer electrical installations (PTE and PTB).-
4th ed.-M.: Energoatomizdat, 1986.- 392 p.
3. SNiP-111-33-76. Production and acceptance of work. Electrical devices. - M.: Stroyizdat, 1977. - 219 p.
4. Knyazevsky B.A., Trunkovsky L.E. Installation and operation of industrial electrical installations. - M: Higher School, 1984. - T75 p.
5. Fedorov A.A., Popov Yu.P. Operation of electrical equipment of industrial enterprises. -M.: Energoatomizdat, 1986.- 280 p.
6. Design of cable networks and wiring / Anastasiev P.I., Branzburg E.Z., Kolyada A.V. and others - M.: Energy, 1980.-384 p.
7. Zabokritsky E.I., Kholodovsky B.A., Mitchenko A.I. Handbook on setting up electrical installations and electrical automation. - Kyiv, Naukova Dumka, 1985. - 702 p.
8. Kinsht N.V., Gerasimova G.N., Kats M.A. Diagnostics of electrical circuits. - M.: Energoatomizdat, 1983. - 192 p.
7. GOST11677-85. Power transformers. General technical conditions.-M: Publishing house of standards, 1988-53p.
Abstract on the topic:
"Operation of electrical equipment in electrical networks."
Introduction
1 Measures aimed at increasing the operational reliability of electrical equipment.
2 Organizational and technical measures to ensure work safety.
3 Operation of electrical equipment of switchgears.
4 Maintenance of complete switchgears.
5 Maintenance of disconnectors.
6 Maintenance of short circuiters and separators.
7 Monitoring the condition of live parts and contact connections.
8 Maintenance of consumer substations.
9 Operation of transformer oil.
Introduction
The development of production is based on modern technologies that widely use electrical energy. In this regard, the requirements for the reliability of power supply to agricultural facilities, for the quality of electrical energy, for its economical use and rational use of material and labor resources in the design of power supply systems have increased.
Electricity supply, that is, the production, distribution and use of electricity in all sectors of the national economy and everyday life of the population, is one of the important factors of technical progress.
Industry, agriculture and transport are developing on the basis of electrification. The main feature of industrial power supply is the need to supply energy to a small number of large-sized objects concentrated on the territory. The economic efficiency of using electricity largely depends on the problem of rational power supply to production. To solve these problems, technical policy solutions are used: replacing wires with SIPs, installing transformers. Operating without replacement for 40 years, using dry switches.
1. Measures aimed at increasing the operational reliability of electrical equipment.
All switchgear equipment is operated in accordance with factory instructions, PTE, PUE and PTB rules and fire safety rules.
All data during planned, routine and overhauls, as a rule, is entered into the operational documentation
In rural power supply, complete outdoor switchgears (KRUN) have become widespread. They are designed to operate at ambient temperatures from -40 to 40 °C. Switchgear units (RU) of 10 kV distribution points (DP) and complete transformer substations of 220-110-35/6-10 kV are assembled from KRUN cabinets. Switches VMG-10, VMP-10K, VMM-10 and others with manual, weight, spring and electromagnetic drives are installed in the cabinets. For rural electrification, complete transformer substations (CTS) for voltages of 6...10/0.4 kV are widely used, consisting of transformers and units manufactured at the factory and delivered to the installation site in assembled form. The KTS equipment will be placed in a metal casing.
The industry produces PTS according to simplified schemes using fuses, short circuits and separators where possible. 35 kV switches are used only in the circuit of pass-through (transit) lines of 35/10 kV transformer substation, in switchgear -35 kV. KTPB 110/35/6 - 10 kV.
In electrical networks for agricultural purposes, the most widespread are SK.TP 35/10 kV with a capacity of 630 ... 6300 kVA*A. manufactured according to primary connection diagrams.
The main tasks during the operation of the reactor plant: ensuring compliance of the operating modes of the reactor plant and individual circuits with the technical characteristics of the equipment; supervision and maintenance of equipment; elimination as soon as possible of malfunctions that lead to accidents; timely implementation of preventive tests and repairs of electrical equipment
2. Organizational and technical measures to ensure work safety.
Preparing workplaces for repair work.
If work is carried out without removing the voltage near live parts that are energized, measures are taken to prevent workers from approaching these live parts.
Such events include:
safe location of workers in relation to live parts;
organization of continuous supervision of working personnel;
use of basic and additional insulating protective equipment.
Work near and on live parts that are energized must be carried out according to instructions.
The person performing such work must position himself so that live parts are in front of him and only on one side; it is prohibited to work in a bent position.
Work on live parts that are energized is carried out using basic and additional protective equipment.
To prepare the workplace when working with partial or complete stress relief, the following technical measures must be carried out in the sequence indicated below:
making the necessary shutdowns and taking measures to prevent the supply of voltage to the place of work due to erroneous or spontaneous switching on of switching equipment;
hanging posters: “Do not turn on - people are working” and, if necessary, installing fences;
connection to the “ground”, portable grounding. Checking the absence of voltage on live parts that must be grounded;
applying grounding (immediately after checking the absence of voltage), i.e. turning on grounding blades or, where they are absent, applying portable grounding connections;
fencing the workplace and hanging posters: “Stop - high voltage”, “Don’t get in - it’ll kill you”, “Work here”, “Get in here”. If necessary, fencing of live parts remaining under voltage is carried out.
3. Operation of electrical equipment of switchgears.
One of the main tasks of operating switchgears is maintaining the necessary reserves in terms of throughput, dynamic, thermal stability and voltage level in the device as a whole and in its individual elements.
Frequency of inspections of switchgears. The frequency of inspection is determined depending on the type of device, its purpose and form of maintenance. The approximate inspection times are as follows: in switchgears serviced by shift personnel on duty at the substation itself or at home - daily. In unfavorable weather (wet snow, fog, heavy and prolonged rain, ice, etc.), as well as after short circuits and when a signal appears and a ground fault appears in the network, additional inspections are carried out. It is recommended to inspect the device in the dark once a week to identify possible corona discharges in areas of insulation damage and local heating of live parts; in switchgear substations with voltages of 35 kV and above that do not have permanent personnel on duty, the inspection schedule is drawn up depending on the type of device (closed or open) and the purpose of the substation. In this case, inspections are performed by the head of the substation group or a foreman at least once a month; transformer substations and distribution devices of electrical networks of 10 kV and below that do not have personnel on duty are inspected at least once every six months. Extraordinary inspections at facilities without permanent personnel on duty are carried out within the time limits established by local instructions, taking into account the short circuit power and the condition of the equipment. In all cases, regardless of the value of the short circuit disconnected power, the circuit breaker is inspected after a cycle of unsuccessful automatic reclosure and the short circuit has been disconnected.
All faults noticed during inspections of switchgears are recorded in the operational log. Malfunctions that disrupt normal operation must be eliminated as soon as possible.
The serviceability of backup elements of switchgear devices (transformers, switches, busbars, etc.) must be regularly checked, including them under voltage within the time limits established by local instructions. Backup equipment must be ready to be turned on at any time without any prior preparation.
The frequency of cleaning switchgears from dust and dirt depends on local conditions and is set by the chief engineer of the enterprise.
Switch maintenance. External inspections of oil switches without shutdown are carried out taking into account local conditions, but at least once every six months, together with inspections of the switchgear. During inspections, the following is checked: the condition of the insulators, fastenings and contacts of the busbar; oil level and condition of oil indicators; no oil leakage from low-volume socket contacts or through gaskets of tank switches.
The oil level of switches largely determines the reliability of their operation. It should not go beyond the oil indicator at ambient temperatures from -40 to 40 °C. An increased oil level in the poles and a correspondingly reduced volume of the air cushion above the oil lead to excessive pressure in the tank during arc extinguishing, which can cause destruction of the circuit breaker.
A decrease in oil volume also leads to destruction of the switch. A decrease in oil volume is especially dangerous in small volume switches VMG-10, VMP-10. If the leak is significant and there is no oil in the oil sight glass, then the switch must be repaired and the oil in it must be replaced. In this case, the load current is interrupted by another switch or the load at this connection is reduced to zero.
Abnormal heating of the arcing contacts of small-volume switches causes darkening and a rise in the oil level in the oil indicator glass, as well as a characteristic odor. If the temperature of the circuit breaker tank exceeds 70°C, the circuit breaker should be repaired.
In areas with a minimum temperature below 20°C, switches are equipped with automatic devices for heating the oil in the tanks.
It is recommended to check the switch drives at least once every three (six) months. If there is an autorecloser, it is advisable to test for shutdown from relay protection with shutdown from the autorecloser. If the switch fails to operate, it must be repaired.
During an external inspection of air circuit breakers, attention is paid to its general condition, the integrity of the insulators of the arc-extinguishing chambers, separators, shunt resistors and capacitive voltage dividers, support columns and insulating braces, as well as the absence of contamination of the surface of the insulators. Using pressure gauges installed in the distribution cabinet, the air pressure in the tanks of the circuit breaker and its supply to the ventilation are checked (for circuit breakers operating with automatic reclosure, the pressure should be in the range of 1.9... 2.1 MPa and for circuit breakers without automatic reclosure - 1, 6... 2.1 MPa). The switch control circuit provides an interlock that prevents the switch from operating when the air pressure drops below normal.
During the inspection, they also check the serviceability and correctness of the readings of devices signaling the on or off position of the switch. Pay attention to whether the dampers of the exhaust visors of the arc-extinguishing chambers are securely closed. Visually check the integrity of rubber gaskets in the connections of arc chamber insulators, separators and their support columns. They control the degree of heating of bus contact connections and hardware connections.
When operating air circuit breakers, accumulated condensate is removed from the tanks 1-2 times a month. During the rainy season, the air supply for ventilation increases; when the ambient temperature drops below -5 ° C, electric heating is turned on in control cabinets and distribution cabinets. At least 2 times a year, the functionality of the circuit breaker is checked by means of control tests for turning off and turning on. To prevent damage to the switches, 2 times a year (in spring and autumn) check and tighten the bolts of all sealed connections.
4. Maintenance of complete switchgears.
The operation of complete switchgears (SGD) has its own characteristics due to the limited overall dimensions of the cells. To protect personnel from accidental contact with live parts that are energized, the switchgear is provided with a lock. In stationary switchgear, screen doors are blocked, which are opened only after the circuit breaker and connection disconnectors are turned off. The withdrawable switchgear has automatic shutters that block access to the compartment of fixed disconnecting contacts when the trolley is rolled out. In addition, there is an operational lock that protects personnel when performing erroneous operations. For example, rolling out the trolley into the test position is permitted by blocking only after the circuit breaker is turned off, and rolling out the trolley into the working position is allowed when the circuit breaker and grounding knives are turned off. Equipment is monitored through observation windows and mesh fences or inspection hatches covered with a protective mesh.
Inspections of switchgear without shutting them down are carried out according to a schedule, but at least once a month. During inspections, the operation of lighting and heating networks and switchgear cabinets is checked; condition of switches, drives, disconnectors, primary disconnecting contacts, locking mechanisms; contamination and absence of visible damage to the insulators; state of secondary switching circuits; operation of switch control buttons.
Systematically, depending on local conditions, it is necessary to clean the insulation from dust and dirt, especially in outdoor switchgear.
When inspecting complete switchgear devices KRU and KRUN, it is necessary to pay attention to: the condition of the seals at the joints of metal structure elements; serviceability of equipment connection to the ground loop; availability of safety and fire extinguishing equipment; operation and serviceability of heating devices for KRUN cabinets; presence, sufficiency and normal color of oil in switches; condition of installation connections; heating of live parts and devices; absence of extraneous noise and odors; serviceability of alarms, lighting and ventilation.
Simultaneously with the inspection, the correct position of the switching devices is checked. The equipment built into switchgear and control gear is inspected in accordance with the operating instructions. When operating the switchgear, it is prohibited to unscrew the removable parts of the cabinet, lift or open automatic curtains if there is voltage in those places where access is blocked by them. In withdrawable-type switchgear cabinets, to ground the outlet lines using disconnectors built into the switchgear, you need to do the following: turn off the switch, roll out the trolley, check the absence of voltage on the lower disconnecting contacts, turn on the grounding switch, put the trolley in the test position.
The fuses in the auxiliary transformer cabinet can only be changed when the load is removed. When carrying out work inside the compartment of a roll-out cart on an automatic curtain, it is necessary to hang warning posters: “Do not turn on! People are working", "High voltage! Life threatening!"
Only operating personnel can roll out the trolley with the switch and install it into the operating position. It is allowed to roll the trolley into the working position only when the grounding switch is in the open position.
5. Maintenance of disconnectors.
When adjusting the mechanical part of three-pole disconnectors, check the simultaneous activation of the knives. When adjusting the moment of contact and compression of the movable knives, they change the length of the thrust or stroke of the limiters and thrust washers, or slightly move the insulator on the base or the jaws on the insulator. When fully switched on, the knife should not reach the contact pad stop by 3 ... 5 mm. The minimum pulling force of one knife and a fixed contact should be 200 N for disconnectors with rated currents of 400 ... 600 A and 400 N for disconnectors with rated currents of 1000 ... 2000 A. The tightness of the contacts of the disconnector is controlled by the value of direct current resistance , which must be within the following limits: for RLND disconnectors (35... 220 kV) for a rated current of 600 A - 220 μOhm; for other types of disconnectors for all voltages with a rated current of 600 A 175 μOhm; 100 A - 120; 1500 ...2000 A - 50 μOhm.
During operation, the contact surfaces of the disconnectors are lubricated with neutral petroleum jelly mixed with graphite. The rubbing parts of the drive are coated with antifreeze lubricant. The condition of disconnector insulators is assessed by insulation resistance, voltage distribution on individual elements of pin insulators, or by the results of testing the insulator with increased power frequency voltage.
The drive block contacts, intended for signaling and blocking the position of the disconnector, must be installed so that the signal to turn off the disconnector begins to operate after the knife has passed 75% of the full stroke, and the signal to turn on - no earlier than the moment the knife touches the fixed contacts.
6. Maintenance of short circuiters and separators.
Short circuiters are devices designed to artificially create a short circuit in cases where the current in the event of a fault in the transformer may be insufficient to trigger the relay protection.
The short circuiter type KZ-35 for a voltage of 35 kV is made in the form of two separate poles with a common drive. The short circuiter is switched on automatically by the SHIK drive when the relay protection is triggered, and is switched off manually.
Switching off power transformers without load, as well as automatically switching off damaged transformers, is carried out by separators. Separators OD-35 are disconnectors of the RLND-35/600 type, equipped with two additional disconnecting springs. The separator can be turned off automatically or manually; turned on only manually using a removable handle.
At 35...110 kV connections with separators and disconnectors installed in series, switching off the magnetizing current of transformers and capacitive currents of lines should be carried out by separators.
With 35 kV separators, it is possible to disconnect a ground fault current of up to 5 A. On average, for 10 km of a 35 kV overhead line, the charging current is 0.6 A and the ground fault current is 1 A.
Short circuits and separators are inspected at least 2 times a year, as well as after emergency shutdowns. During inspections, special attention is paid to the condition of insulators, contacts, and the grounding wire passed through the window of the current transformer. If traces of burning are detected, the contacts are cleaned or replaced.
The duration of movement of the moving parts of a short-circuiter for voltages of 35 and 110 kV from the application of a pulse to closing the contacts should be no more than 0.4 s, and the duration of movement of the separator from the application of a pulse to the opening of the contacts should be 0.5 and 0.7 s, respectively.
During the operation of short circuiters and separators, special attention should be paid to the most unreliable components: open or insufficiently protected springs from possible contamination and icing, contact systems, swivel joints, as well as unprotected bearings protruding from the rear side.
When setting up the short circuiter and separator, pay attention to the reliable operation of the separator blocking relay (BRO), which is designed for currents of 500...800 A. Therefore, at short circuit currents. less than 500 A, the ground spike should be replaced with a wire and passed through the current transformer several times. If this is not done, the BRO relay will tighten the armature indistinctly and thereby release the locking mechanism of the separator drive until the short-circuit current is turned off. Premature shutdown of separators is one of the reasons for their destruction.
Current repairs of disconnecting devices, as well as checking their operation (testing), are carried out as necessary within the time limits established by the chief engineer of the enterprises. The scope of routine repair work includes: external inspection, cleaning, lubrication of rubbing parts and measurement of direct current contact resistance.
Unscheduled repairs are carried out in the event of detection of external defects, heating of contacts or unsatisfactory insulation conditions.
Adjustment of the short-circuiter and separator consists of checking the operation of the drive for turning on and off, checking the position of the knives and the installation of the tripping spring of the drive with the blocking relay BRO, adjusting the stroke of the cores of the electromagnets and relays.
7. Monitoring the condition of live parts and contact connections.
The condition of live parts and contact connections of busbars and switchgear devices can be identified during inspections.
The heating of detachable connections in closed distribution devices is monitored using electric thermometers or thermal candles and temperature indicators.
The operation of an electric thermometer is based on the principle of measuring temperature using a thermistor glued to the outer surface of the sensor head and covered with copper foil.
The heating temperature of contact connections is determined using a set of thermal candles with different melting temperatures.
Reversible, reusable films are used as thermal indicators, which change color when heated for a long time. The thermal indicator must withstand, without destruction, at least 100 color changes during prolonged heating to a temperature of 110 °C
8. Maintenance of consumer substations.
The reliability of consumer substations largely depends on the correct operation, which must be carried out in accordance with existing guidance and instructional materials. Operational and preventive work on transformer substations is carried out in order to prevent and eliminate possible damage and defects during operation.
The scope of this work includes systematic inspections, preventive measurements and checks. Routine inspections of TP are carried out during the daytime according to the approved schedule, but at least once every six months.
After emergency shutdowns of supply lines, in case of equipment overloads, sudden changes in weather and natural phenomena (sleet, ice, hurricane, etc.), extraordinary inspections are carried out. At least once a year, engineering and technical personnel perform control inspections of the transformer substations. Usually they are combined with the acceptance of objects for operation in winter conditions, with inspections of 10 or 0.4 kV overhead lines, etc.
To maintain TP in technically sound condition, scheduled preventive maintenance is carried out, which allows them to ensure long-term, reliable and economical operation.
Inspections, repairs and preventive tests of equipment at 10/0.4 kV transformer substations are mainly carried out comprehensively in one time frame, without removing the voltage, and, if necessary, with partial or complete shutdown of the equipment.
When inspecting mast-mounted substations from the ground, the condition of fuses, disconnectors and their wires, insulators, fastening of wires to the busbar, grounding slopes and contacts, fastening and relative position of high and low voltage wires, the condition of the substation structure, the condition of wood and reinforced concrete, the presence and condition of warning signs are checked. posters, as well as the integrity of locks and stairs. When inspecting substations of the KTP type, they additionally check the contamination of the surface of metal cases, cabinets, the tightness of the doors and the serviceability of their locks, and the condition of the supporting foundations.
When inspecting transformer substations and package transformer substations, it is necessary to pay attention to the following: for load switches, disconnectors and their drives - there are no traces of overlap and discharges on insulators and insulating rods; position of knives in fixed contacts; external condition of the arc extinguishing knives and chambers at the circuit breaker; correct position of the drive handles; serviceability of the flexible connection between the knife and the input terminal at the RLND disconnector;
for PC-type fuses, compliance of the fuse-links with the parameters of the equipment being protected, integrity and serviceability of the cartridges, correct location and fastening of the cartridges in the fixed contacts, condition and position of the fuses trip indicators;
for arresters - the absence of traces of an overlap arc on the surface, correct installation, the condition of the external spark gaps of tubular arresters and the correct location of gas exhaust zones;
for bushings, support and pin insulators - absence of chips, cracks and traces of arc overlap;
for the 10 kV switchgear busbar - the absence of traces of local heating of the contacts at the points of connection to the equipment and in the busbar connections, the condition of the painting and fastening of the busbars;
for cable devices - the condition of the cable couplings and funnels, the absence of mastic leakage, the integrity of the lugs, the presence of markings, the grounding of the couplings and funnels, the condition of the cable pits and passages through the steps;
for low voltage switchgear (0.4 kV) - the condition of the working contacts of switches, fuses and circuit breakers, the absence of traces of soot, overheating and melting on them, the condition of current transformers, protection relays and arresters of type RVN-0.5, the integrity of fuse links and their compliance with consumer parameters, serviceability of photo relays, integrity of seals and protective glasses on metering and measuring devices, condition of 0.4 kV busbar contacts and its fastenings.
To eliminate malfunctions in the operation of transformer substations and package transformer substations noticed during inspection, in cases that cannot be delayed until the next routine or major repair, preventive selective repairs are carried out with the replacement of individual elements and parts. These works are performed by operational operating personnel.
9. Operation of transformer oil.
For reliable operation of oil-filled equipment, it depends on the condition of the transformer oil filled in the equipment.
Transformer oil in operation must undergo abbreviated analysis and tg measurement in accordance with the “Standards for Testing Electrical Equipment” (SPO OPGRES, 1977) within the time limits specified in Table. 4. and after current repairs of transformers and reactors.
Table 4. Frequency of sampling transformer oil
| Name | Rated voltage, kV | Frequency of oil sampling |
| Transformers of power units with a capacity of 180 MVA and more | 110 and above | At least once a year |
| Transformers of all capacities | 330 and above | Same |
| Other transformers and reactors | Up to 220 (inclusive) | At least once every 3 years |
| Oil-filled bushings are not sealed | 500 | During the first two years, 2 times a year, then once every 2 years |
| Same | 110-330 | During the first two years of operation, once a year, then once every three years. |
| Oil-filled, sealed bushings | 110-750 | Not checked |
| On-load tap-changer contactors | ---- | After a certain number of switchings according to the factory instructions, but at least once a year. |
Drying oil.
In energy systems, oil is dried in two ways: by sucking dry nitrogen or carbon dioxide through it at room temperature; a vacuum of 20...30 kPa is created over the oil; spraying oil at room temperature and a residual pressure of 2.5... 5.5 kPa. To speed up drying, the oil is heated to 40 ... 50 ° C with a residual pressure of 8 ... 13 kPa.
In small repair enterprises, oil is dried by heating or standing at a temperature of 25...35°C. Sludge is an extremely simple, cheap and oil-harmless drying method. Its disadvantage is the long duration of the operation.
Drying oil by heating is also simple, and the oil can be heated by a variety of methods, including in the transformer’s own tank. But heating the oil for a long time can lead to its deterioration.
Oil purification.
Under operating conditions, the oil not only becomes moisturized, but also becomes contaminated. The oil is purified from water and mechanical impurities by centrifugation and filtration.
Centrifugation separates water and impurities that are heavier than oil. The oil temperature should be 45...55°C. At low temperatures, the high viscosity of the oil prevents the separation of water and impurities, and when the temperature rises above 70°C, it is difficult to separate the water due to the onset of vaporization and the increased solubility of water in the oil. In addition, at elevated temperatures, intensive aging of the oil occurs.
Filtration - pressing oil through a porous medium (cardboard, paper, cloth, layer of bleaching material or silica gel) - is carried out using filter presses. Filter paper and cardboard not only trap impurities, but also absorb water.
Soft and friable cardboard has the greatest hygroscopicity, but it does not retain sludge and coal well and releases a lot of fibers. Alternating sheets of soft and hard cardboard in the filter press allows you to obtain well-purified oil.
It is advisable to filter oil at a temperature of 40...50 °C, since at higher temperatures the hygroscopicity of cardboard decreases and the solubility of water in oil increases. Contaminated cardboard can be rinsed in clean oil, dried and put back into use. To clean 1 ton of oil, about 1 kg of cardboard is required.
The filter press is usually turned on after the centrifuge to remove residual sludge and water. It provides almost extreme purification of oil from water and the highest electrical strength of the oil. The advantages of the filter press include its ability to operate at normal temperatures, the absence of mixing oil with air, and the ability to purify oil from the smallest particles of coal. However, centrifuges are capable of purifying oil containing emulsions, whereas a filter press is not suitable for purifying such oils.
A centrifuge is used to purify oils located in the tanks of operating transformers, but with strict adherence to safety precautions. The use of silica gel or bleaching clays in filter presses as an additional filter medium significantly reduces the acid number of the oil.
List of used literature.
Pyastolov A.A. Eroshenko G.P. Operation of electrical equipment - M.: Agropromenergo, 1990 - 287 p.
Eroshenko G.P. Pyastolov A.A. Course and diploma design for the operation of electrical equipment - M.: Agropromizdat, 1988 - 160 p.
Rules for the construction of electrical installations - M.: Energoatomizdat, 1986 - 424 p.
E.A. Konyukhova Electrical supply of objects. - M, 2001-320 p.
P.N. Listova Application of electrical energy in agricultural production, 1984
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The operation of electrical equipment of any facility, including a private home, no matter how large it is, must be carried out in accordance with the requirements of the “Rules for the Use of Electricity”, “Rules for the Technical Operation of Consumer Electrical Installations” and “Safety Rules for the Operation of Consumer Electrical Installations”. These rules are mandatory for all electricity consumers, regardless of the departmental affiliation of the house. Responsibility for the technical condition and safe operation of electrical installations, electrical wiring, electrical equipment (devices, apparatus, etc.) of private property rests with its owner.
Particular attention should be paid to electrical safety, as well as the constant readiness of all types of fire-fighting devices, if any. When accepting electrical equipment for operation, it is necessary to obtain from the developer the as-built design documentation and documents on acceptance and the possibility of connecting the electrical installations of the facility to the electrical networks of the area.
For private property, it is mandatory to carry out a power supply project (with a total installed capacity of more than 10 kW), which must contain the following materials:
- external and internal power supply diagram;
- internal wiring diagram (type of wires and installation method);
- diagram of input devices;
- calculation of electrical loads;
- selection of circuit breakers and fuse links;
- grounding or grounding (if necessary);
- installation of a residual current device at the input (if necessary, at the point where the facility is connected to the power supply network);
- electricity metering.
For private property with a total installed power of less than 10 kW, a lightweight design drawing can be made, which should reflect:
- diagram of external and internal power supply indicating the types and settings of protective devices, sections and grades of wires, design currents, electricity metering devices, connections to the supply network;
- situational plan for the location of electrical equipment, laying of cables, wires, grounding and neutral conductors;
- specification of electrical equipment products and materials;
- explanations, instructions, notes (if necessary).
At facilities located geographically in one place, as a rule, only one electric meter should be installed. For garden and country houses, it is allowed to install a switching device or fuse in front of the meter to turn it off.
The electrical safety of people both inside the facility and outside must be ensured by a set of electrical protective technical measures, including the use of residual current devices, both at the point of connection of electrical networks and inside the facility, re-grounding of the neutral wire at the air input, grounding of electrical receivers, and the use of double insulation input to the object. For grounding, a separate conductor with a cross-section equal to the phase one must be used, laid from the input cabinet (box). This conductor is connected to the neutral conductor of the supply network in front of the meter. The use of a working neutral conductor for this purpose is prohibited.
The connection of electrical installations to the electrical network is carried out by the personnel of the energy supply organization that issued the technical specifications. The private owner-consumer must ensure the serviceability of his electrical installations. He is not allowed to connect an electrical load in excess of that permitted in the technical specifications, nor to increase the rated current values of fuses and other protective devices.
The relationship of this consumer with energy supply organizations is determined by the “Rules for the Use of Electrical Energy” and the agreement for the use of electrical energy concluded by the consumer with the energy supplying organization.
The owner of a private house must provide:
- maintaining electrical equipment and networks in working condition and its operation in accordance with the requirements of modern regulatory and technical documentation;
- reliability of electrical installations and safety of their maintenance.
If the owner is interested in the uninterrupted operation of his electrical equipment, he must ensure the availability of spare parts and materials.
Electricity supplied to the house and site is necessary for electric lighting, electric heating, electric heating of food, powering radio and other equipment, alarm systems, driving electric pumps and power tools (drills, saws, etc.). It should be remembered that to use electricity for thermal purposes, special permission from the Energy Supervision authorities is required. Its distribution according to these needs is carried out from the main input-distribution device, which must be installed near the input of the supply distribution line coming from the transformer substation.
If there is a personal plot, then electricity supply is also provided for auxiliary structures and premises. It is carried out using insulated wires of overhead lines or intra-site wiring cables through an electric meter installed in the house.
The design of electrical installations, their operation and repair must meet the requirements of the system of labor safety standards and safety regulations. Protective equipment, devices and tools used when servicing electrical installations must comply with current regulatory and technical documents on labor protection. The owner or the personnel hired by him must follow the labor protection instructions.
Electrical installations must be provided with the necessary protective equipment according to established minimum standards.
The owner of the house must have technical documentation, according to which his electrical installations are approved for operation:
- master plan with buildings, structures and underground electrical communications;
- approved as-built design documentation (drawings, explanatory notes, etc.) with all subsequent changes;
- acts of acceptance of hidden work, testing and adjustment of electrical equipment and electrical installations;
- technical passports of the main electrical equipment;
- certificates of conformity for materials and equipment.
To properly operate electrical installations, you need to know how electricity is supplied to a building or facility.
If the input is three-phase, then 3 linear wires and 1 neutral or zero wire are supplied to the house, which is both a working (N) and a protective (PE) conductor.
In modern power supply circuits, instead of one neutral wire, two can be supplied, one of which is protective (PE, and its color is green-yellow), and the other is working (N - blue color).
Most often, in a transformer substation, the neutral point of the transformer, from which the neutral wire is supplied to all sections, is “solidly” grounded, that is, connected to the ground, and the potential of this neutral wire corresponds to the zero potential of the earth (which is why the wire is sometimes called zero). The remaining three wires have such potentials that the voltage between any two wires (voltage is the potential difference) is usually 380 V, and the voltage between any of the line wires and the neutral wire is in this case 220 V. If the neutral wire is grounded, then the voltage between any of the line wires and the ground or grounded structure of the building, overhead line support, etc. is also 220 V, which should never be forgotten. The same voltage can also appear between the ground and any live part of electrical equipment connected to these linear wires by electrical wiring, terminals of plug sockets, switches, etc.
Currently, in the overwhelming majority of cases, input into an individual house is carried out using a single-phase circuit. In this case, one of the linear wires is supplied to each house in the village and always neutral (zero). As already noted, currently a distinction is made between neutral protective (PE) and neutral working (N) conductors. They can be combined into one or approached the consumer separately with two wires. Thus, either three or two wires can be connected to the house.
Entry into the building is carried out with an insulated wire or cable with a non-flammable sheath. The cross-section, grades of wires and cables are selected taking into account their purpose and conditions of use in accordance with the “Rules for Electrical Installations”. It should be noted that these Rules are currently undergoing changes, and it is necessary to use the most modern edition, in particular, 1999.
A device for re-grounding the neutral wire at the input to the facility is mandatory for all three-phase inputs; the need for such for a single-phase input is determined in each specific case by the design (in particular, this is necessary for an overhead power line). Re-grounding of the neutral wire at the input is carried out using a ground electrode consisting of one or better several steel rods with a diameter of at least 12 mm or pieces of angle steel with a wall thickness of at least 4 mm, providing the required resistance depending on the resistivity of the soil, which is determined by the project.
In places where input wires are connected to branch wires, contact connections are made only using clamps. Connecting input wires to branch wires in the span is prohibited. This may result in electric shock to people and animals.
Electrical connections to the premises are made through the walls in insulated pipes so that water cannot accumulate in the passage and penetrate into the premises. For fire safety purposes, passages for entries in walls made of combustible materials are made in steel pipes.
When operating overhead lines, the shortest distance from the input wires into the facility, as well as the intra-facility electrical wiring wires, to the ground surface should be at least 2.75 m.
The cross-section of wires of branches and inputs into buildings must be at least, mm²:
It is necessary to monitor the sag of the wires, prevent them from swinging excessively, as well as tree branches touching the wires, climbing plants and other vegetation.
The operation of input and distribution devices is carried out in accordance with the established boundary of operational responsibility between the energy supply organization and the given facility, where maintenance is carried out by the owner or hired personnel. The boundary of operational responsibility is determined by the Act of delimitation of operational responsibility with the organization operating the energy networks of the given area.
All input and output lines, as well as protective, switching and measuring equipment must have the necessary inscriptions and signs.
Protective (and other) equipment must strictly comply with design parameters.
The premises of input and distribution devices must meet the requirements of ventilation, humidity and temperature and always have appropriate protective equipment for safety precautions. Based on the “Rules for the Operation of Consumer Electrical Installations,” measurements of insulation resistance, grounding resistance, and checking the operation of circuit breakers and other protection devices must be systematically carried out. Installation and operation of electrical energy metering devices are carried out in accordance with the requirements of Energosbyt, “Rules for Electrical Installations” and manufacturer’s instructions. All measuring and metering equipment for electrical energy, as well as information and measurement systems must be in good condition and ready for operation. All electrical energy metering devices are subject to mandatory state or departmental inspection.
State inspection of calculated electrical energy metering instruments and standard measuring instruments is carried out by the energy supply organization within the time limits established by state standards, as well as after repair of these instruments.
The owner of a private home bears responsibility for the safety and cleanliness of external elements of electrical energy metering devices. He must immediately report any violations in their work to the energy supply organization. Opening of electrical measuring instruments is permitted only to personnel of this organization. Replacement and checking of settlement meters is also carried out by staff. The energy supplying organization must be immediately notified of any defects or failures in the operation of electric energy meters.
The energy supply organization must seal:
- settlement meters;
- switching or protective device when installed in front of the meter.
When commissioning grounding devices of electrical installations, the installation organization, in addition to documentation, must submit acceptance test reports.
When operating and repairing grounding devices, it must be borne in mind that each part of the electrical installation that is subject to grounding (grounding) must be connected to the grounding (grounding) network using a separate conductor. The sequential connection of grounded parts of an electrical installation to the grounding or neutral protective conductor is prohibited. Grounding and neutral protective conductors must have a coating that protects them from corrosion. Openly laid steel grounding conductors must be painted black. To determine the technical condition of the grounding device, the following must be periodically carried out by a specialized organization:
- measurement of the resistance of the grounding device and random inspection with opening of the soil of the grounding elements located in the ground;
- checking the condition of the circuits between grounding conductors and grounded elements, as well as the connections of natural grounding conductors with a grounding device.
For everyone distribution boards There must be inscriptions and indicators of incoming and outgoing lines, settings of circuit breakers, fuses and other necessary information. A distribution board is a device where electricity is supplied through distribution lines from the input distribution device and where, with the help of protective devices (fuses, circuit breakers), the group lines extending from the distribution board that directly supply power to electrical receivers (lamps, household and technological equipment, etc.) are protected. .P.).
During operation and routine repairs of switchboards, it is necessary to especially carefully monitor the condition of the protective equipment. Fuses must be calibrated. Under no circumstances should you use wire “bugs” instead of standard fuse links! Automatic switches must strictly comply with design parameters and, in accordance with the “Rules for the operation of consumer electrical installations”, be tested for operation. If uncalibrated or faulty safety equipment is used, there is a high risk of fire. In control panels, it is necessary to check that the contact solution of contactors, relays and magnetic starters corresponds to the passport data. During routine repairs, the contact surfaces of circuit breakers and switches are returned to normal condition. They are cleaned of dirt, oxides, and soot.
During the operation of distribution and group networks of a building, special attention should be paid to hidden wiring. It is necessary to monitor the insulation of the wires. Insulation resistance measurements should be carried out systematically in accordance with the “Rules for the operation of consumer electrical installations”. Moreover, measurements of insulation resistance must be carried out by a licensed organization. It is necessary to pay attention to the reliability of fastening of installation equipment: switches, plug sockets, etc., to the density of contacts connecting lines to distribution and installation equipment and to their temperature.
When operating a cable line with voltage up to 1000 V, in addition to the above documentation, technical documentation must be drawn up and handed over to the customer (executive design of the cable line, made on a scale of 1:200, as-built drawing of the route indicating the installation locations of couplings; acts of hidden work indicating intersections and approaches of cables with all underground communications; certificates for the installation of cable couplings). When accepting a newly constructed cable line into operation, tests must be carried out in accordance with the requirements of the “Rules for the Construction of Electrical Installations” and the “Rules for the Operation of Consumer Electrical Installations”.
When using unarmored hose-covered cables, special attention must be paid to the condition of the hoses. Cables with hoses that have through breaks, burrs and cracks must be replaced. Openly laid cables, as well as all cable couplings, must be equipped with tags indicating the brand, voltage, cross-section, number or name of the line; and on the coupling tags - the coupling number and installation date. Tags must be resistant to environmental influences and located along the length of the line every 50 m on openly laid cables, at route turns and in places where cables pass through fire-resistant partitions and ceilings (on both sides). Cable line inspections are carried out at the following times: cable routes laid in the ground - at least once every 3 months; cable routes laid along the walls of buildings - at least once every 6 months. If signs of destruction of metal sheaths due to electrical, soil or chemical corrosion are detected on a cable line, urgent measures should be taken to prevent them. When excavating cable routes or carrying out excavation work, appropriate supervision over the safety of cables must be ensured. Digging trenches and pits in places where cables and underground structures are located should be done with extreme caution, and at a depth of 0.4 m or more - only with shovels (in winter with heating of the soil). In this case, it is necessary to ensure that a layer of soil at least 0.3 m thick is maintained from the surface of the heated layer to the cables. Thawed soil should be discarded with shovels. The use of crowbars and similar tools is strictly prohibited. Excavation with earth-moving machines at a distance closer than 1 m from the cable, as well as the use of jackhammers, crowbars and picks to loosen the soil above the cables to a depth of more than 0.3 m at the normal cable laying depth (0.7 m) is prohibited. The use of impact and vibrating mechanisms is permitted at a distance of at least 5 m from the cables. Before starting work, a control opening of the route must be carried out to clarify the location of the cables and the depth of their laying under the supervision of the electrical technical personnel of the organization operating the cable line.
Electric lighting plays a big role in the interior and exterior design of an individual home, and also provides comfort that is impossible in the absence or insufficient natural light. The power, shape, color of lamps and fixtures, as well as their location, are very important. Lighting in all rooms and landscape of a private house must comply with the standard, unless this contradicts the wishes of the owner. Lamps must only be factory-made and meet the requirements of state standards and technical specifications. Emergency lighting fixtures (if provided) must be distinguished from them by signs or coloring. When the main power source is turned off, the emergency lighting network must be automatically turned on from an independent power source (battery, etc.). The emergency lighting network must be made without plug sockets. In distribution boards of the lighting network, all circuit breakers must have inscriptions with the name of the connection, permissible value current settings, and on fuses - indicating the value of the fuse-link current. The use of uncalibrated fuse links in all types of fuses is prohibited. A supply of calibrated fuse links, lamps and lamps of all voltages of a given lighting network is desirable.
Portable hand-held lamps must be powered from a mains voltage of no more than 42 V, and in case of increased risk of electric shock - no more than 12 V.
Plugs for 12 or 42 V appliances must not fit into 127 and 220 V outlets. All outlets must be labeled with the rated voltage.
The use of fluorescent lamps and DRL lamps (high-pressure mercury gas-discharge lamps) not mounted on rigid supports for portable lighting is prohibited.
Installation and cleaning of electric lighting network luminaires, replacement of burnt-out lamps and calibrated fusible links, repair and inspection of the electric lighting network must be carried out by specialists.
When the hanging height of lamps is up to 5 m, they can be serviced from ladders and stepladders. If the luminaires are located at a greater height, they are allowed to be serviced from stationary bridges (scaffolding) and mobile devices, subject to mandatory compliance with safety measures and voltage relief. Out of order fluorescent lamps, DRL lamps and other sources containing mercury must be stored packaged in a special room. They must be periodically removed for destruction and decontamination to designated areas.
Checking the condition of stationary equipment and electrical wiring of emergency and work lighting, testing and measuring the insulation resistance of wires, cables and grounding devices must be carried out when putting the electric lighting network into operation, and subsequently according to the appropriate schedule. Defects found during inspection and inspection must be eliminated as soon as possible.
Electric motors, ballasts, instrumentation, protection devices, as well as all electrical and auxiliary equipment must comply with the requirements of the Electrical Installation Rules and other applicable regulatory and technical documents. Electric motors and the mechanisms they drive must have arrows indicating the direction of rotation. On electric motors, their switching devices, ballasts, fuses, etc. There must be inscriptions with the name of the unit and (or) mechanism to which they relate. Fuse links must be calibrated and have the stamp of the manufacturer or department responsible for the electrical equipment of the enterprise, indicating the rated current setting. The use of uncalibrated inserts is prohibited. In the event of an emergency shutdown of the electric motor by the protection device, it should be restarted only after inspection, control measurements of insulation resistance and checking the serviceability of protective devices.
The electric motor must be immediately disconnected from the network in the following cases:
- in case of accidents with people;
- when smoke or fire appears from the electric motor, as well as from its control gear;
- if the drive mechanism breaks down or an abnormal knock occurs;
- with a sharp increase in vibration of the unit bearings;
- when bearings are heated above the permissible temperature specified in the manufacturer's instructions.
Currently, private homes use a large amount of foreign equipment. In this regard, it must be remembered that when using imported electrical equipment, special attention should be paid to the relevant factory instructions, which should not contradict Russian norms and regulations.
