Schematic diagram of the enterprise's power supply. Types of power supply schemes for industrial enterprises

Power supply from the power system can be carried out according to two schemes (Fig. 1):
deep entry of a double main line with a voltage of 35...220 kV into the territory of the enterprise with connection by tapping from both and several pairs of transformers;
with one powerful GPP for the entire enterprise. The first scheme (see Fig. 1, a) is used at large enterprises that occupy large territories and have areas for the passage of a line with a voltage of 35...220 kV. The second scheme (see Fig. 1, b) is used in medium-sized enterprises with concentrated loads. These diagrams are the main electrical drawings of the project, on the basis of which all other drawings are made, network calculations are made and the main electrical equipment is selected.

Rice. 1. External power supply schemes for large (a) and medium-sized (b) enterprises

When designing power supply for industrial enterprises using diagrams high voltage power sources, distribution points and transformer substations with busbars, main switching equipment (oil or air circuit breakers, reactors), placement of automatic transfer switches, all transformers and high voltage electrical receivers (high-voltage electric motors, converter units, electric furnaces, etc.) should be shown. . Next to the corresponding graphic symbols, you need to indicate the rated voltage of busbars, types of circuit breakers, rated currents and reactances of reactors, rated powers and voltages of transformer windings and their connection diagrams, rated rectified currents and voltages of converter units, rated powers of electric motors. Near the images of cable and overhead lines, indicate their length, as well as the grades and cross-sections of cables, material (copper or aluminum) and cross-sections of wires of overhead lines and current conductors.

Rice. 2. :
a - single; b - end-to-end with two-way power supply; c - ring; g - double; TP1-TP6 - transformer substations

Voltage 110 kV is most widely used for power supply to enterprises from the power grid. The increase in the capacity of industrial enterprises, the reduction in the minimum power of transformers by 110/6... 10 kV to 2500 kV A contribute to the use of a voltage of 110 kV to power enterprises of not only medium, but also small power.
Voltage 220 kV is used for power supply from the power system of large enterprises, creation of deep inputs with disaggregation of substations. In some cases, the use of 220 kV voltage in solar power plants is facilitated by the close distance from the enterprise to the route of 220 kV power lines.
A distribution network with a voltage of 6 (10) kV (less often 35 kV) is an internal network of an enterprise that serves to transmit electricity from the buses of the gas distribution point and the gas distribution point to distribution and transformer points via overhead lines, cable lines and conductors. Depending on the category of loads and their location, the distribution network from one or two independent sources is built according to a radial, main or mixed scheme.

Trunk circuits can be single, end-to-end with two-way power supply, ring and double.
A single circuit (Fig. 2, a) is used for consumers of the third category. This scheme requires fewer lines and switches. Two or three TP transformers with a power of 1000...1600 kV A or four or five transformers with a power of 250...630 kV A are connected to one main line (the limitation is introduced by the sensitivity of the relay protection). The disadvantage of the scheme is the lack of a backup power supply channel in case of line damage. Therefore for cable lines such a scheme is not used, since the time to find places of damage and repair cables can exceed 24 hours.
An end-to-end circuit with two-way power supply is more reliable (Fig. 2, b). The main line is connected to different power sources. Under normal conditions, it is open at one of the substations. The scheme is used to supply consumers of the second category.
The ring circuit (Fig. 2, c) is created by connecting two single lines with a jumper for a voltage of 6 (10) kV. The circuit is used to supply power via overhead lines to consumers of the second category. In normal mode, the ring is open and the substations are powered via single mains. But when any section of the network fails, the power supply to the transformer is interrupted only for the duration of operations to disconnect the damaged section for repairs and turn on the jumper disconnector.
The double circuit (Fig. 2, d) is quite reliable, since in case of any damage on the line or in the transformer, all consumers (including the first category) can receive electricity from the second line. Input of backup power occurs automatically using ATS devices. This scheme is more expensive than those discussed above, since the cost of constructing lines doubles.

Rice. 3. Radial power supply circuits for powering consumers of the third (a), second (b) and first (c) categories of power supply reliability

Radial circuits (Fig. 3) are used to power concentrated loads and powerful electric motors. For consumers of the first and second categories, double-circuit radial circuits are provided, and for consumers of the third category, single-circuit circuits are provided. Radial circuits are more reliable and easier to automate than main circuits.
The diagram shown in Fig. 3, a, is intended for consumers of the third category. When connecting an automatic reclosing device (AR) of an overhead line, this scheme can be used for consumers of the second category, and in the presence of emergency power supplies - also for consumers of the first category.
The circuit shown in Fig. 3, b, is used for consumers of the second category. In some cases, it can also be used for consumers of the first category. When the voltage disappears on one of the bus sections, some of the consumers connected to the other section remain in operation.
The diagram shown in Fig. 3, c, is used for consumers of the first category. When the voltage on one of the bus sections disappears, power supply to consumers is restored by automatically turning on the sectional switch.

Rice. 4.
is carried out along radial lines, and backup is carried out along one end-to-end highway, shown in Fig. 4 dashed line.
In all the diagrams shown, the sectional devices are in the off state in normal mode. Mainly in distribution networks

Mixed schemes combine elements of mainline and radial schemes (Fig. 4). Basic nutrition for each consumer
open circuits are used that meet the requirements for limiting short-circuit currents and independent operating mode of sections.
Closed networks are rarely used, since short-circuit currents increase significantly (up to two times), switches are required at both ends of the lines, and relay protection becomes more complicated. However, closed networks have a number of advantages: greater power reliability for receivers, which are always connected to two (or more) power sources; lower energy losses due to more uniform network load; less voltage drop. These advantages are especially significant when powering large installations. In such installations, starting a powerful electric motor can cause large voltage deviations in an open circuit, making starting and self-starting of the engine under load impossible, since the starting torque becomes lower than the resistance moment on the motor shaft.
Switching on transformers and lines for parallel operation sharply (almost by half) reduces the equivalent resistance of the power supply network and ensures successful engine starting. In some cases, such inclusion is used only during the start-up of the main engines (for example, at large pumping and compressor stations, where engines of comparable power to transformers are used).
Electricity supply to metallurgical plants with a full production cycle (blast furnace, steelmaking and rolling shops) is carried out, as a rule, from the nearest power system through a power system substation at a voltage of 110 or 220 kV and from the local plant thermal power plant (Fig. 5). The local plant CHP plant is usually connected to the 110 kV (220 kV) power grid.
The shock loads of rolling shops must be absorbed by the power system. This must be taken into account when developing a power supply project for a metallurgical plant. The power system must be powerful to provide the minimum permissible level voltage fluctuations in the supply network 110 kV (220 kV).
To limit the harmful effects of shock cyclic loads on the quality of electricity in the power supply system, the following measures are recommended.

1. Limitation of reactive power consumed by valve converters when operating with deep regulation.
2. Development and implementation of electric drives with reduced reactive power consumption.

Rice. 5. Block diagram of power supply of blooming 1150 (ion drive)

3. Approximation of power sources to electrical receivers with shock load; power supply of electric arc furnaces at increased voltage; power supply of large electric motors directly from the GPP or PGV, bypassing the corresponding workshop substation, etc.
4. Reducing the reactance of lines feeding large electrical receivers through the use of cables and conductors with reduced reactivity, reducing the reactivity of reactors, etc.; use of switches with increased limit switched current.

Rice. 6.

5. Connecting shock and quiet loads to different branches of a dual reactor (Fig. 6), the parameters of which must be selected based on the conditions for stabilizing the voltage on the reactor branch supplying power receivers with a quiet operating mode.

1. Use of transformers with split windings at GPP and PGV secondary voltage with a splitting coefficient Kp > 3.5, when sharply variable shock loads are allocated to one of the power windings.
2. Power supply of groups of electrical receivers with shock loads (with significant power) through separate transformers.
3. The use of synchronous compensators with high-speed (thyristor) excitation, as well as synchronous electric motors with free reactive power to limit the influence of shock and valve loads.

For synchronous electric motors receiving power from common buses with shock loads, automatic high-speed excitation regulators should be used.
Of the listed schemes, the most widely used, especially for medium-power enterprises, are schemes with split windings of GPP transformers and dual reactors (see Fig. 6).
Voltage fluctuations on sections with a quiet load under the influence of a sharply changing load on other sections will be less than when all loads are connected to one bus section.

A diagram is a graphical representation of the elements of a particular structure indicated in the drawing. In addition, there are schemes electronic devices, including integral and presentation of any material in a simplified form. A single-line power supply diagram, for example, of a private house, is also no exception to the basic definition.

Regarding the term “single-line power supply diagram,” we mean a graphical representation of the three phases of the power supply network connecting various electrical elements in the form of a single line. This introduction of a symbol greatly simplifies and makes power supply circuits less cumbersome. By definition, an electrical diagram is a document containing, in the form of symbols and images, the component elements of products, the principle of operation of which is based on the use of electrical energy and their connection with each other. The rules according to which all types of electrical circuits are carried out, including a single-line power supply diagram, are defined by GOST 2.702-75, and the implementation of circuits digital electronics and computer technology are determined by GOST 2.708-81. Conditional display three-phase voltage power supply, for example, is shown in figure “a”, and its simplified display, which was the reason for the appearance of single-line diagrams, is shown in figure “b”.

In addition, to visually display a three-phase connection on the diagrams, several symbols are used, such as a crossed out line with the number “3” located next to the input or output of the wiring, and a straight line crossed out by three oblique segments. For single-line power supply diagrams, the designations of devices, starters, contactors, switches, sockets and other elements are used in accordance with GOST and European rules for the design, design and installation of electrical appliances.

The linear power supply diagram, examples of which are shown in Figures 1 and 2, displays the simplest connection and interaction of lighting elements, power supply and sockets for household appliances.

Industrial circuits for providing electricity to enterprises and connecting equipment do not differ fundamentally from a single-line power supply circuit for a private home or other structure.

Types of power supply schemes

When designing power supply systems, there are schemes of operational responsibility, balance sheet, executive and calculation, which are designed to reflect both the planned work and the existing system or the division of systems by consumers in order to establish safety boundaries.

Executive power supply diagram

is a document drawn up at an operating facility, reflecting the current state of networks, devices included in these networks, and recommendations for eliminating shortcomings and defects, if any were identified as a result of the appropriate set of measures.

In cases of designing new construction projects, a design installation diagram is drawn up. This element of a construction project includes structural electrical diagram, functional electrical diagram, electrical installation diagram, and, if necessary, cable plans and basic electrical drawings. In addition, if, for example, a power supply diagram for a cottage is drawn up, then, in accordance with the latest trends in suburban construction, a fire safety project is included in it.

Structural diagrams

present general information about the electrical installation, expressed in indicating the interconnections of power elements, such as transformers, distribution boards, power lines, tie-in points, etc.

Functional diagrams

are performed mainly to abstractly transfer the functions of the mechanisms to which power is supplied, their interaction with each other and the impact on the overall situation from a safety point of view. Such projects are used mainly in the design of industrial facilities with a high occupancy of areas with machines, mechanisms and equipment, which can be indicated on the diagram in any way convenient for the designer. In addition, these documents often do not indicate the dimensions of objects, and they are not planning documents.

Schematic diagrams

It is customary to perform in accordance with GOST and standards in force in countries that were not previously part of the USSR. The standards in force in the global community meet the requirements of national manufacturers agreed with government agencies. These include IEC, ANSI, DIN and other standards.

Wiring diagrams

In the design of any objects, correctly drawn up installation diagrams are of particular importance, which must be clearly compatible with architectural solutions and construction elements, load-bearing structures of buildings and structures. Although there are no special requirements for the design of drawings when designing wiring diagrams, it is worth paying attention to the clarity of the indicated dimensions not only of equipment and wire cross-sections, but also the actual cable diameters, dimensions of fasteners and auxiliary materials.

In addition to the listed documents, including cable plans, there are electrical special diagrams that are used to design and display individual components. So in microelectronics, topological diagrams are used to display the microcrystal of an integrated circuit, and to quickly display the real state of the equipment used in a particular system. Such diagrams are called mnemonic diagrams and are made in the form of posters with active elements, which are signaling equipment and instruments, as well as various imitation devices. Modern mnemonic diagrams are implemented on computer monitors with functions for making decisions by the user or operator in manual mode.

In general, the design of the power supply system, displayed graphically, in addition to compliance with state building codes and regulations, must contain additional information that provides complete and reliable information about the equipment listed in the specification, emergency shutdown calculations for both the entire facility and its individual parts. In addition, it should contain information about the autonomous power supply system, which is especially relevant when designing individual houses located away from central highways.

If you are the happy owner of a private house in which there is no light yet, then the question arises of how to supply electricity to the structure without violating any instructions, and to do this with minimal time and money.

Stages of connecting a private house to power supply

Power supply to a private and any other facility is the inclusion of the facility in the network of electrical energy consumers. It is connected to its distribution point. If you decide to become a consumer, to do this you need:

• conclude an agreement with the electric energy supplier (EPS);
• obtain technical specifications (TU);
• complete design documentation;
• carry out construction and installation work;
• obtain permission to operate the facility from the electrical energy supplier.

Agreement with (PES)

List of documents required for concluding an agreement for the supply of electricity in the new edition in accordance with the “Rules for the use of electrical energy”

To conclude an agreement you must:

1. Application addressed to the deputy. Director of PES regarding the conclusion of the relevant agreement indicating the location, full name. applicant.
2. A copy of a document defining ownership of an object or land plot.
3. Obtain technical specifications from PES. A sample of technical specifications is presented in APPENDIX Fig.3 Fig.4.
4. Complete the project “Electrical supply of a private house” in the design organization and coordinate it with the PES. A sample project is presented in APPENDIX Fig. 1, Fig. 2.
5. Provide acts of delimitation of balance sheet ownership and operational responsibility of the parties carried out in the project “Electrical supply of a private home”.
6. Provide a single-line power supply diagram made in the “Electrical supply of a private house” project. An example of the circuit can be seen in APPENDIX Fig. 5.
7. Provide information regarding metering devices (type of electricity meter, its class, electrical connection diagram, installation location, vandal-proof protection).
8. Provide information about electrical installations for heating and hot water supply needs, permission to use them (up to 15 kW of thermal power is issued by Energosbyt PES, over 15 kW of thermal power is issued by Oblenergo) or a certificate of their absence.
9. Protocols for checking grounding and insulation of electrical wiring.
10. Application addressed to the deputy. chief at tech. acceptance and sealing of the meter.
11. Receipt for technical acceptance and sealing.
12. The supplier of electrical energy is PES (Electric Network Enterprise). PES is a legal entity that represents the owner of generating energy sources and (or) electrical network. On a contractual basis, PES provides electricity to consumers.

Note: If a house is being built on a site where electricity has already been supplied and where an electric meter has already been installed, then you contact the PES regarding the issue of increasing the declared power, in the event that, according to calculations, the supplied electrical power will not be enough for you.

If you are going to build a house on a site where electricity has not previously been supplied, then you need to start working with PES from the moment you receive the architectural and construction plan. It is necessary to obtain permission to connect powerful consumers (welding machine, machines, etc.) required during construction, and then request an increase in power, if necessary. This way we will avoid penalties from the PES at the construction stage.

The power supply to a private home is carried out on the basis of the technical specifications (TU), the electricity supplier who supplies electricity to the area where the construction of our private facility is taking place, or the PES TU, the energy that is beneficial for us to use.

Issuance of technical specifications

Technical specifications are issued based on your application to the PES based on the power we request from consumers (kW) and voltage level (kV).

The application must indicate:

• name of the private property;
• physical adress;
• voltage value (0.23; 0.38), kV;
• type of supply voltage (single-phase, three-phase);
• The use of electricity in heating systems and water heating must be specified.

The power consumption for the construction period is obtained based on the total electrical power of the equipment used during construction; for a permanent period we receive on the basis of the project “Electrical equipment and lighting of the house”, carried out taking into account architectural, construction and design projects.

We obtain the required voltage from technical characteristics electrical equipment used at your construction site and in everyday life and included in the project “Electrical equipment and lighting of the house”.

We determine the type of input according to the voltage required by our electrical equipment, laid down in the project “Electrical Equipment and Lighting of the House”: we select three-phase input if we have electrical receivers with a voltage of 380 V, if we have electrical receivers with a voltage of 220 V, but the total electric power is large, then it makes sense for us to distribute it across phases. In other cases, we select a 220 V input.

The application must indicate that we are going to use electricity to heat the house and heat water.

Note 1: The application must be accompanied by a copy of the decision of local authorities to build a house, a copy of the general plan for the allocation of land for development, agreed with the architectural and planning service of the district or city level, or a copy of the construction passport, and for a privatized plot - a copy of the state act or a certificate of ownership.

Note 2: You can get the specifications without the “Electrical equipment and lighting of the house” project if you yourself calculate the power of the equipment and lighting.

You can first perform the calculation of the power that we are going to indicate in the application yourself.

We will draw up a list (list) of all electrical equipment that we are going to install in the house and adjacent outbuildings (electric oven, washing machine, air conditioners, electric water heaters, electric motors, machines used in everyday life, etc.) at this stage and with a view to the future, indicating the power and voltage, which we will read in the passport. This statement will be useful to you in the future when completing a project on electrical equipment, lighting and power supply. It must reflect all electricity consumers. It is at this stage that you need to think about what electrical systems will be installed in the house. Such systems should include:

• interior and exterior lighting of the house and surrounding area,
• air conditioning system,
• artificial supply and exhaust ventilation system,
• electric heating systems,
• "warm floors"
• installation of an automatic control system for gates and barriers.

We may need:

• fire alarm systems,
• video surveillance,
• communications (Internet, mini-PBX),
• automatic gas and water control systems.

Everything should be reflected in the list. At this stage there should be no trifles and no miscalculations either. You can take a design project of the object to help. The biggest consumers of electricity are electric heating and hot water supply. Against their background, the number of light bulbs, televisions, computers, and telephones is not noticeable.

Here the criterion is the declared power value of 10 kW 220 V.

Coordinating power over 10 kW requires much more effort and money. Therefore, if the power does not exceed 10 kW, then it is preferable to declare it to the maximum. If you have a power of, say, 9.8 kW, then declaring above 10 kW is economically unjustified.

Note: In the APPENDIX, Fig. 3 and Fig. 4 it is clearly visible: the technical specifications were issued for one facility, but different capacities are indicated and what the PES requirements for the customer follow from this.

Let's select consumers for a voltage of 380 V (for example, machine tools, water heaters, water pumps) and summing up their power we get the power of the power equipment P380. Let's carry out the same procedure with consumers for a voltage of 220 V and get P220.

You can also calculate the power required for indoor and outdoor lighting yourself down to one Watt, and I advise you to do it yourself! Use the Dialux program. It may not be used if all the rooms are of a standard size and there are no special requirements for them, and the issue is solved by a standard chandelier and local lamps on the walls, and if your room is classified as “special”.

Note: DIALux is a lighting calculation and design program. It was developed by the German Institute of Applied Lighting Engineering. The program is provided free of charge and uses data from lighting devices from various manufacturers, which are entered into the luminaire database, in a format supported by the Dialux program. Working with the program is intuitively simple and will not cause serious difficulties in operation, so try to understand it in order to save on lighting design. Working with the program begins with drawing a floor plan. Then, by selecting the required lamps from the database and placing them in various places, they check the illumination level of the room, achieving the required result. Normalized illumination in living rooms and kitchens is 200 lux, outdoors 30 lux, in utility rooms 75-100 lux.

We enter the number, types and power of lamps into the list, add them up and get the lighting power of Rosv220. Our lighting is designed for 220 V.

The preliminary installed power is shown:

at a voltage of 380 V P=(P220+Rosv220)/3+P380;

at a voltage of 220 V P = P220 + Rosv220.

Note: The average private consumer is designed for a power of 5 kW 220 V. This means that the consumers of electricity in such a house are lighting, a TV, a refrigerator, a washing machine, a microwave oven, and all in one copy. If there are some other consumers, then 5 kW is not enough!

The application has been drawn up, the attached documents are ready and with a clear conscience we go to the PES to receive the technical specifications.

Development of project documentation

The calculation of power consumption can be carried out accurately and reasonably at the first stage by a designer in the project “Electrical equipment and lighting of a private house”. Moreover, you will still need to complete such a project after receiving the technical specifications.

In this case, we need to take a list of our electrical equipment, the final agreed architectural and construction plans of the house by floor with explications of the premises and look for a designer who will perform this calculation for us.

The designer will charge $150-200 for the work, depending on the area of ​​the building.

Note: Unreasonably increased power can lead to significant costs. Again, I suggest you pay attention to APPENDIX Fig. 4 and Fig. 5

After receiving an application from the consumer, PES issues technical specifications within two weeks, which indicate:

• place of connection to the general electrical network;
• voltage, kV;
• agreed load of the connected private property, kW;
• requirements for the input device, automation, insulation and overvoltage protection;
• requirements for an electricity meter;
• the need to obtain permission from the State Energy Supervision authorities to use electricity for heating and hot water supply;
• validity period of these technical conditions;
• mandatory approval of the power supply project with the PES and the local State Energy Supervision Authority;
• data on the prospects for network development;
• recommendations for attracting a design organization and using standard projects;
• recommendations for organizing the operation of an electrical installation.

Again, I suggest you pay attention to APPENDIX Fig. 3 and Fig. 4.

At the same time, the PES that issued the specifications is responsible for their sufficiency in ensuring the possibility of safe operation of the electrical installation of a private property object connected to its networks.

We are starting to implement the project “Electrical equipment, lighting and power supply of a private home.” Without the involvement of specialists, it will be quite difficult to carry out and coordinate the external power supply of the house, but knowing what should be in the project, what is attached to the contract, and what the homeowner faces, will allow you to avoid many pitfalls.

Now you can return to our designer again, or contact a design organization using the recommendation of the PES, or start searching for a design organization yourself to conclude an agreement for the implementation of the “Electrical equipment, lighting and power supply” project for your private building based on technical specifications.

The quality of the projects of the designer and design organizations will be equivalent, but the designer’s project will cost less: $300-400. A good option is to use the services of a design organization that was recommended by the PES - there will be no delays or complaints when approving the project!

The best option for completing a project is to enter into an agreement with a design company that will carry out not only the project, but also further construction and installation work on this project.

Note: Before concluding an agreement for the implementation of the project “Electrical equipment, lighting and power supply”, you must ensure that you have permission to carry out design, construction and installation work. This permit is a license from the Ministry of Construction, Architecture, Housing and Communal Services of the country with a list of types of work permitted by this license. The license is issued on stamped paper, which indicates its number, series, validity period, entity, to whom it was issued and certified by the official seal of the head of the state architectural and construction inspection.

In the contract with the designer, we stipulate all the issues that the design solutions must have, and which we must submit for approval to the PES, namely:

If the total installed power is above 10 kW, then the following documents should be included in the power supply project

• calculation of installed capacities of electrical equipment and lighting;
• diagram of input distribution devices;
• calculation of settings of fuses and circuit breakers;
• calculation of the incoming residual current device (RCD);
• installation of an electricity meter;
• internal wiring diagram, where it is necessary to indicate the types of wires and options for their installation;
• external power supply diagram made on the basis of the general plan;
• internal power supply diagram;
• balance of property delineation;
• provide a grounding or grounding diagram;
• If necessary, explanations, instructions, and notes are provided.

If the resulting total installed power is less than 10 kW, then you can make a design drawing where you need to reflect:

• an external power supply diagram made on a situational plan (general plan) and an internal power supply diagram where the types of protective devices with calculations and settings must be indicated. Here the cross-section and grades of wires are indicated, the calculation of currents, the installation location of electricity meters, and the location of connection to the supply network are given;
• situational plan indicating the location of electrical equipment, the location of cables and wires, indicating the connection points of grounding and neutral conductors;
• a separate document presents the balance of property delineation, where networks belonging to different owners are highlighted in different colors;
• A specification of electrical equipment, products and materials must be provided, which indicates the quantity, type and supplier of this equipment and materials;
• if necessary, explanations, instructions, notes are given, see Fig. 2;
• the power supply project (project drawing) must be agreed upon with the energy supply organization that issued the technical specifications and the local State Energy Supervision Authority. It is advisable to carry out the approval by the designer, and the customer controls the deadlines for the designer to complete the project and approval. The approval fee is $10-20.

All design solutions must comply with:

1. DBN V.2.5-23-2003 “Design of electrical equipment for civil facilities”;
2. SNiP 2.08.01-89 “Residential buildings”;
3. DNAOP 0.00-1.32-01 Rules for electrical installations. Electrical equipment of special installations";
4. DBN V2.5-28-2006 “Natural and artificial lighting”
5. SNiP 21-01-97 “Fire safety of buildings and structures”
6. RD 34.21.122-87 “Instructions for the installation of lightning protection of buildings and structures”
7. PUE Electrical installation rules: chapters 1.7, 3.1; sections 2, 6, 7.

Links to these documents must be in the project provided by the designer. An example can be seen in Fig. 1.

A few important points to consider during the design process:

• The design must necessarily provide for the separation of power circuits and lighting networks. This is necessary in order to select the correct types and brands of cables. For power networks, the cable is selected with a large cross-section. You can check the correct choice of cable based on the expected loads. Nowadays, aluminum wires are practically not used for electrical wiring, although they are cheaper than copper wires, but they last less and are very impractical to use.
• Pay special attention to checking the types of wires and cables installed in rooms with high humidity. These are baths, saunas, bathrooms. The insulation of these cables and wires must comply with the requirements of 413.2 GOST 30331.3 - the use of equipment of class II or with equivalent insulation. This protective measure is used to prevent the appearance of dangerous voltage on accessible parts of electrical equipment during an insulation breakdown.
• When concluding an agreement with a design organization, enter the clause “Approval of the project by the design organization itself and issuing you a finished project with approval,” but at the same time we must remember that responsibility for the technical condition and safe operation of the wiring and electrical appliances of our house rests with you and me - the owner Houses.

According to the technical conditions, the project completed by the designers must be agreed upon with the PES that issued the technical conditions and the local State Energy Supervision Authority.

We bring the completed project with technical specifications to the PES. Having received a receipt for payment and paid for approval, we will try to use our personal strengths to reduce the waiting period for approval! The approval period is usually indicated by the PES immediately - this is usually two weeks, but no more than a month, depending on the complexity of the specifications, but if all points of the specifications have been fulfilled, then there is no need to worry - the documents can be returned only with approval.

Attention: This article presents prices for 2009. Be careful.

APPLICATION

Figure 1. Sample project for power supply of a private house

Figure 2. Sample project for power supply of a private house

Figure 3. Specifications for 4 kW power

Figure 4. Specifications for power 48 kW

Figure 5. Single-line diagram of power supply to the statement of balance sheet ownership

The distribution of electrical energy throughout the enterprise at voltages above 1000 V is carried out using radial or main lines. By radial line we mean one in which all the loads are concentrated at its end (Fig. 1, a, b); under the main line - one whose loads are distributed along its length, i.e. power is taken from which is carried out at several points (Fig. 2). A circuit (network) consisting only of radial lines is called a radial circuit (network), only those consisting of main lines is called a main line, and those of radial and main lines are called a mixed circuit.

At the first stage of energy distribution, the following are used:

a) with transmitted powers of about 50 MB-A or more - main or radial lines of 110 - 220 kV, feeding deep input substations;

b) with transmitted powers from 15 - 20 to 60 - 80 MB-A - main (sometimes radial) current conductors 6 - 10 kV;

c) with transmitted powers less than 15-20 MB-A - main or radial cable networks of 6 or 10 kV.

At the second stage of distribution, both radial and main circuits are used.

Trunk circuits with voltage 6 - 10 kV for cable lines are used:

a) with the location of substations conducive to the straight passage of the highway;

b) for a group of technologically connected units, if stopping one of them requires shutting down the entire group;

c) in all other cases when they have technical and economic advantages.

Radial circuits should be used for loads located in different directions from the power source.

The advantages of radial circuits include ease of implementation and reliability of operation of the electrical network; as well as the possibility of using high-speed protection and automation.

Disadvantages of radial circuits: 1) a large number of high-voltage equipment used, which leads to increased costs of switchgears and an increase in their dimensions; 2) increased consumption of cable products due to an increase in cable cross-sections compared to economically feasible ones and the total length of cable lines.

Picture 1.

Trunk power supply circuits make it possible to reduce costs by reducing the number of devices used and reducing the length of supply lines. In the diagrams of Fig. 2, a shows the power supply of workshop transformer substations using so-called single mains. With one-way power supply to such mains, their main disadvantage (compared to radial circuits) is the lower reliability of power supply, since if the main is damaged, all consumers powered by it are disconnected. Power reliability will be increased when voltage is supplied to the second end of the line from another source. In this case, a ring main is formed, from which, in the presence of two-transformer substations, receivers of the second category can be powered. To increase the reliability of main circuits, other modifications can be used, for example, a scheme of double end-to-end main lines (Fig. 2, 6), when two main lines are alternately connected to each section of substations; This circuit allows you to power the load of the first category.

At medium- and high-power enterprises, the so-called deep input is widely used - this is a power supply system with the maximum possible proximity of the highest voltage (35 - 220 kV) to consumer electrical installations with a minimum number of intermediate transformation stages and devices. At medium power enterprises, deep entry lines come directly from the power system.

Figure 2.

Topics. In this case, the lines of the 35-220 kV supply network are practically combined with the lines of the distribution network of the first stage of distribution. At larger enterprises, deep inputs depart from the UPR or GPP. Deep entry lines pass through the territory of the enterprise in the form of radial cable lines or overhead lines or in the form of highways with branches to the largest points of electricity consumption. The diagram of a deep input substation 35 - 220 kV is shown in Fig. 3. With a deep voltage input system of 35 - 220 kV, the enterprise can install step-down transformers 220/6 - 10 kV; 110/6 - 10 kV; 35/6 - 10 kV or 35/0.4 kV. The use of deep input schemes reduces the length of the 6-10 kV distribution network or even eliminates it altogether. Thus, deep entry reduces distribution network costs and increases the reliability of power supply.

Workshop networks with voltages up to 1000 V are carried out using radial, main and mixed circuits.

Figure 3.

Radial circuits are characterized by the fact that from a power source, e.g. switchboard 380/220 Lines feeding large electrical receivers (for example, engines) or group distribution points depart from the workshop transformer substations, from which, in turn, independent lines feed smaller group distribution points or small electrical receivers.

Networks of pumping or compressor stations, as well as networks of dusty, fire-hazardous and explosive premises, are made radial. The distribution of electricity in them is carried out by radial lines from distribution centers located in separate rooms. Radial circuits provide high power reliability; automation can be easily used in them. The disadvantage of radial circuits is that they require high costs for installing distribution boards, laying cables and wires.

Trunk circuits are most widely used in

more or less uniform distribution of load over the workshop area (for example, to power the motors of metal-cutting machines in metal machining shops). Trunk circuits are also used in other cases. Thus, if a technological unit has several electrical receivers that carry out a single, connected technological process, and the loss of power to any of them necessitates stopping the operation of the entire unit, then in such cases the reliability of the power supply is fully ensured with a main power supply. In some cases, when a very high degree of power reliability is required in a continuous technological process, two-way power supply of the main line is used.

The use of trunk circuits makes it possible to avoid the use of a bulky and expensive switchgear or low-voltage switchboard.

In practice, mixed schemes are usually used to supply workshop consumers - depending on the nature of production, the environment, etc.

In general, the in-plant power supply system can be represented as a multi-level complex hierarchical system. In the general case, the number of levels of such a system is six, and the number of levels increases as their importance in the power supply system increases.

The first level (1UR) includes the terminals of individual electrical receivers to which voltage is supplied, the second (2UR) includes group distribution points 380/220 kV (power cabinets - ShS, lighting boards - ShchO, etc.) and distribution busbars (ShR ), to the third (3UR) - shop transformer substations, to the fourth (4UR) - 6 - 10 kV RP buses, to the fifth (5UR) - 6 - 10 kV buses of gas substations, to the sixth (6UR) - the entire enterprise as a whole (i.e. e. 6UR refers to the points of separation of the networks of the consumer and the power supply organization).

In particular cases, the number of levels may be more or less than six, depending on specific conditions. So, for example, between the 1UR and the SAM there may be not one group distribution point, but two - if smaller distribution points are powered from the gas distribution center, from which small power receivers receive power. In this case, the number of levels increases. Or the enterprise may not have a fourth level RP - in this case the number of levels is reduced. In addition, levels with different numbers can be combined. Thus, when powering high-voltage (6-10 kV) electric motors from the RP buses, 2UR and 4UR are combined, and directly from the GPP buses - 2UR and 5UR. Of greatest interest is the combination of different levels with 6UR, reflecting the fact that consumers can receive power from different levels - depending on the type of electricity collection point. You can count the number of consumers receiving energy from the level n+1 an order of magnitude less receiving it from the level P. If 90% of consumers (including apartments and individual residential buildings) are powered by 2UR, then from 3UR - 9%, from 4UR - 0.9%, from 5UR - 0.09% and from 6UR - 0.01%. The division of SES into levels reflects the difference in properties characterizing consumers of different levels, and, as a consequence, the difference in the requirements they place on power supply: with an increase in the level number, these requirements become more stringent. This concerns, first of all, the requirements for reliability and quality of electricity. The organization of servicing of consumer electrical installations depends on the level at which the electricity reception point is located. If 6UR and 2UR, then the consumer does not have permanent electrical personnel servicing his electrical installations. Maintenance of electrical equipment is carried out by personnel specially invited for this purpose. At 6UR and 3UR, the consumer, as a rule, already has electricians, but there are no special electrical engineers; The operation of the electrical equipment is carried out by the chief mechanic's department. When 6UR and 4UR, a department of the chief power engineer and an electrical shop are created at the enterprise, servicing electrical installations up to 1000 V; major repairs of electrical equipment are carried out by special third-party organizations; electrical installations above 1000 V are also serviced by third-party organizations. In cases where 6UR and 5UR, the enterprise may already have personnel who have access to servicing 6 - 10 kV equipment, but its overhaul, as a rule, is carried out by third parties.

Both all elements of newly constructed, reconstructed and modernized solar power plants, and solar power plants as a whole, must meet all the requirements of the current Electrical Installation Rules. When operating SES, the standards of the Rules for the Technical Operation of Consumer Electrical Installations (PTE), as well as the Safety Rules for the Operation of Electrical Installations (PTB) must be observed. Personnel operating electrical installations are called electrical personnel (electrical personnel). All electrical personnel are divided into five qualification groups (the highest group is the fifth). To obtain (and confirm) the group, electrical personnel periodically undergo a knowledge test - for knowledge of the provisions (PTE), (PTB) and job descriptions and equipment being serviced related to their field of activity.