Determination of voltage on the low voltage side of the substation. Classification of electrical substations and distribution devices. Basic definitions

One of the main means of regulating voltage in electrical networks is to change the transformation ratios of transformers (autotransformers) at step-down substations of electrical networks.

Transformers (autotransformers) have special branches from the windings that allow you to change the transformation ratio and, therefore, regulate the voltage. Switching of branches can be carried out by a switching device without excitation (PBU) when the transformer is disconnected from the network or by a load regulation device (OLD) without disconnecting the transformer from the network.

Also, to regulate voltage, special linear regulating transformers are used, installed either at substations or directly into power distribution lines leaving the substation.

Regulating branches of two and three winding transformers are made in the high voltage winding. The current in the higher voltage winding is less than in other windings, which makes the operation of the on-load tap-changer easier and reduces its weight and size.

In order to simplify the consideration of the basic principles of regulation of transformation ratios, we will further consider circuits of transformers and control devices in a single-line design, i.e. for one phase of symmetrical three-phase devices.

In Fig. 8.1 shows a schematic diagram of a transformer with a tap-changer device. The primary winding (high voltage winding) has a zero tap and four adjustment taps: 2.5% and 5%. The secondary winding (low voltage winding) has a constant number of turns. The zero branch of the off-circuit tap corresponds to the nominal transformation ratio. Other branches correspond to changes in the transformation ratio in the range of 5% (from 0.95 to 1.05). To switch control branches, it is necessary to disconnect the transformer from the network. These switches are made rarely, for example when the load changes seasonally. Such transformers cannot be used to regulate voltage during loads during the day.

The schematic diagram of a transformer with on-load tap-changer is shown in Fig. 8.2. The primary winding has an unregulated (a) and adjustable (b) part.

The number of branches on the adjustable part of the primary winding of such transformers is greater than that of transformers with PCB. For example, for a transformer with a rated higher voltage of 115 kV, the voltage regulation range is 9 1.78%. These transformers have, in addition to the zero one, 18 more branches. From Fig. 8.2 it can be seen that for branches +1,+2,…. the turns of the regulated winding are connected in accordance with the unregulated winding. When working on these branches, the transformation ratio increases. For branches -1, -2,..., the turns of the adjustable winding are connected opposite the unregulated winding. When working on these branches, the transformation ratio decreases.

On the regulated part of the winding there is a switching device consisting of movable contacts K3 and K4, contactors K1 and K2 and a current-limiting reactor LR, at the middle point of which the output of the unregulated winding is connected. When the transformer operates on any branch, the load current of the primary winding is distributed equally between the two parts of the reactor. The currents in different parts of the reactor are directed in opposite directions, so the resulting magnetic flux of the reactor and its inductive reactance are practically zero.

Let the conditions of voltage regulation require switching from branch +2 to branch +1. To do this, contactor K1 is turned off, and the moving contact K3 is switched to branch +1. Contactor K1 turns on. The winding section between taps +1 and +2 is shorted to the LR reactor. The significant inductance of the reactor limits the equalizing current, which arises due to the presence of voltage in the closed section. After this, contactor K2 is turned off, moving contact K4 is moved to position +1 and contactor K2 is turned on.

Transformers with on-load tap-changers allow you to regulate the voltage when the load changes during the day. Such transformers are equipped with automatic voltage regulators (AVRs), which respond to changes in voltage on the secondary winding of the transformer, issuing a command to switch the tap-changer taps.

To increase the reliability of the operation of the on-load tap-changer, it is necessary to exclude its operation during minor voltage deviations, as well as during significant but short-term voltage deviations. For this purpose, the AVR has a dead zone slightly larger than half of one control stage. In this case, the AVR issues a signal to switch taps if the voltage is closer to the next regulation stage than to the one at which this moment the transformer is working.

To prevent the on-load tap-changer from tripping during short-term significant voltage deviations in the AVR, a time delay of 1 to 3 minutes is provided.

Autotransformer on-load tap-changers operate similarly.

Linear regulating transformers TL are used to regulate voltage in individual lines or a group of lines and are used in following cases:

When reconstructing existing networks that use transformers without load regulation. In this case, to regulate the voltage on the substation buses, TL is connected in series with an unregulated transformer, Fig. 8.3a;

To regulate voltage on outgoing lines. In this case, TL are connected directly to the lines, Fig. 8.3b.;

To regulate voltage at substations with transformers with on-load tap-changers, from which consumers with different load types are powered, Fig. 8.3v. The nature of the load of consumer 3 differs significantly from the nature of the load of other consumers;

To regulate low voltage at a substation with autotransformers equipped with on-load tap-changers in the medium voltage winding, Fig. 8.3g.

There are 5 contacts under load, as in the on-load tap-changer of a power transformer. One end of the primary winding 6 of the series transformer 2 is connected to the midpoint of the secondary winding 4 of the supply transformer, the other to the switching device 5. The secondary winding 7 of the series transformer is connected in series with the high voltage (HV) winding of the power transformer, and the additional EMF of the winding 7 is added to the EMF HV windings.

If phase voltage is applied to the primary winding3 of the supply transformer, then the EMF of the HV winding of the power transformer is modulo-regulated using the on-load tap-changer described above (Fig. 8.5a).

In this case, the module of the resulting EMF of the HV winding of the power transformer and winding 7 of the linear control transformer (LR) is equal to: ,

where is the EMF module in the phase of the HV winding of the power transformer.

If winding 3 is connected to two phases and , then the resulting EMF of windings HV and 7 changes in phase (Fig. 8.5b): .

Voltage regulation in modulus, when and are in phase (Fig. 8.5a), is called longitudinal. With such regulation, the transformation ratio is a real value. Voltage regulation in phase, when and are shifted by 90° (Fig. 8.5b), is called transverse. Voltage regulation in modulus and phase is called longitudinal-transverse (Fig. 8.5c). In this case, winding 3 is connected to phases and. With longitudinal-transverse regulation, the transformation coefficient is a complex value.

The connection circuits and operating principle of a linear regulator connected to the lower winding of an autotransformer or to power lines coming from the CPU are similar.

§6 Voltage regulation by changing the network resistance. (14V)

The consumer's voltage depends on the magnitude of voltage losses in the network, which in turn depend on the resistance of the networks. For example,

the longitudinal component of the voltage drop in the line is equal to:

Where - power flows and voltage at the end of the line; , - its active and reactive resistance, Fig. 8.6.

In distribution networks, active resistance is greater than reactive resistance, i.e. When the cross-section of the lines in distribution networks changes significantly, the consumer voltage also changes.

Therefore, in these networks, the cross-section is often selected based on the permissible voltage loss.

In supply networks, on the contrary, , is therefore largely determined by the reactance of the lines, which depends little on the cross-section. Changing reactance is used to regulate voltage. To change the reactance, you need to include a capacitor in the line.

Let's assume that the voltage at the end of the line before installing the capacitor is below the permissible level:

We connect capacitors in series in the line so as to increase the voltage to the permissible level:

An electrical substation (PS) is a key unit that makes it possible to organize a power supply system at facilities of various sizes, which is determined by the load-bearing level of the installation itself. Depending on the design, this type of equipment can increase or decrease the voltage, and this directly determines the intended purpose of the substation.

Main areas of application

The electrical distribution substation is responsible for receiving and converting electricity. In this case, the voltage can be lowered or increased, and, if necessary, straightened, which is determined by the needs of the consumer. At the next stage, the received energy is distributed. In cases where the voltage value is expected to increase, electricity is received, for example, from a generator, and then transmitted to the power line.

Let's watch a video of where electricity comes from:

If electricity is supplied from power lines, then in order to send it further to the consumer it is necessary to reduce the voltage. The serviced objects are production workshops, residential or urban types, microdistricts, etc.

Part of the equipment

Electrical stations and substations can be delivered to the installation site in a finished, fully assembled form or in separate blocks and assemblies, and the equipment will be called complete. Main elements and components:

1. A chamber for installing equipment in it, including a transformer, as well as a busbar. There are two versions: completely closed without mesh inserts and partially closed with a mesh-type fence.
2. Prefabricated tires. Together they represent an entire system. Electrical stations and substations can also contain separate sections, which are the same busbars separated by a switching unit.
3. A conductive system comprising busbars or cables that are connected to insulators. Such structures are located on supporting supports. It is with the help of this unit that electricity is transmitted.
4. Transformer in quantities from one to several units.
5. The switchgear ensures the reception and further distribution of energy. The switchgear consists of several units: switching equipment, busbars, control and protection elements.

Electrical substation design

Various types of electrical equipment of substations such as switchboards. devices are found in several versions: open, closed, complete. The first and second of these options involve outdoor or indoor use. And complete versions, like any equipment with a similar name, are a prefabricated installation consisting of units ready for connection.

Overview of existing species

Equipment of this kind is classified primarily by purpose.

In this case, the following are distinguished:

• Generating;
• Consumer;
• Conversion and distribution.

Electric generating stations and substations represent equipment responsible for generating energy, while consumer versions receive electricity from power lines and meet the needs of objects for various purposes. Converter-distribution analogues perform the function of converting voltage for the purpose of further distribution.

Equipment of this type is distinguished according to the set of tasks that are solved with its help:

• Transformer installations;
• Conversion analogues.

The electrical circuit of a transformer distribution substation allows you to lower or increase the voltage in accordance with the needs of the consumer, while converter technology is responsible for changing the electrical parameters (type of current, frequency value).

There is a division of such installations according to the level of importance in the energy supply system:

1. Major downgrades;
2. Deep input;
3. (power electric vehicles different types, be it railway trains, ground or underground vehicles);
4. Complete - they are a prefabricated installation consisting of individual units completely ready for connection.

Let's watch a video of what a traction substation is like:

Another type of classification represents electrical stations and substations that differ in connection diagram:

• Dead-end – receive power from one neighboring substation;
• Walkthroughs are equipment that represents single line with two-way power supply;
• Nodal units are a key link, since in addition to supply units they are also connected to transit ones;
• Branch lines are part of the wiring of the power supply system.

In addition to the above listed versions, there is a special type of such equipment - an autonomous multi-type electrical substation. Its peculiarity lies in the ability to simultaneously combine two important functions: electricity generation, as well as its distribution further along the network, from where it goes to the consumer.

Parameters and connection diagram

There are several basic requirements for drawing up connection diagrams for the main components of electrical equipment that must be met:

1. Reliability of energy supply, consumer safety.
2. Minimum costs for operation and maintenance of equipment.
3. Convenience of working with technology.
4. Minimal risk of error in emergency situations when switching equipment operating modes is required.

The main electrical connection diagram of the distribution substation should depict the main components of the installation (switch switchgear, power transformers, switching devices, protective elements and control systems).

There are two ways of drawing up diagrams: multi-line and single-line. In the first case, all phases of the installation are necessarily shown, while the second option involves including an image of only one phase due to identity.

Figure 1 shows a single-line electrical diagram of a distribution substation, which reveals the operating principle of the installation that meets the needs of consumers of the third category. The main parameters are the value of the HV and LV voltage (on the higher and lower side), as well as the power of the installation and the type of transformer.

Location standards and requirements

The main step-down substations should be located in close proximity to the areas of greatest load; workshop installations are always located as close as possible to the consumer. A more preferable option is a complete substation, since in this case there is no strong dependence on the building part during its installation.

Stand-alone installations require additional costs for organizing supply networks, and at the same time losses increase. Much more preferable is the built-in option with a remote transformer.

There are permissible limits for the location of electrical equipment of this type regarding explosive serviced objects: from 0.8 to 100 m. The choice of a certain value from this range is determined by the degree of danger, as well as the location option (open, closed).

In order to ensure safe operation, as well as a sufficient level of reliability of operation of electrical equipment, the Government Russian Federation the security zone of the electrical substation is determined. This means that in the specified territory adjacent to such installations, there are restrictions on the use of land plots for their intended purpose.

Thus, given the wide choice of designs for electrical substations, their choice should be based on the compliance of the main parameters of the equipment with the operating conditions. This is the only way to ensure the safe operation of the installation, which is a key point when drawing up a connection diagram for such equipment. The complexity of a project to organize an energy supply system lies in the need to select a large number of equipment, as well as organize its coordinated operation. Therefore, a complete substation is often the preferred option.

Electrical engineering specialists know what power stations and substations are, what they are intended for and how they are designed. They know how to calculate their power and all the necessary parameters, such as the number of turns, wire cross-section and magnetic core dimensions. This is taught to students in technical universities and technical schools. People with a humanities education realize that structures are often standing apart in the form of houses without windows (graffiti lovers love to paint them), they are needed to supply energy to homes and businesses, and you should not penetrate them, this is eloquently evidenced by the frightening emblems in the form of skulls and lightning bolts attached to dangerous objects. Many people may not need to know more, but there is no such thing as too much information.

A little physics

Electricity is a commodity that you have to pay for, and it is a shame if it is wasted. And this, as in any production, is inevitable; the only task is to reduce unnecessary losses. Energy is equal to power multiplied by time, so in further discussions we can operate with this concept, since time flows constantly, and it is impossible to turn it back, as the song says. Electrical power, in a rough approximation, without taking into account reactive loads, is equal to the product of voltage and current. If we look at it in more detail, the formula includes the cosine phi, which determines the ratio of consumed energy to its useful component, called active. But this important indicator is not directly related to the question of why a substation is needed. Electrical power thus depends on the two main participants of Ohm's and Joule-Lenz's laws, voltage and current. Low current and high voltage can produce the same power as the opposite, high current and low voltage. It would seem, what's the difference? But it exists, and it’s very big.

Heat the air? Excuse me!

So, if you use the active power formula, you get the following:

• P = U x I, where:

  U - voltage, measured in Volts;
  I - current, measured in Amperes;
  P - power, measured in Watts or Volt-Amps.

But there is another formula that describes the already mentioned Joule-Lenz law, according to which the current released during the passage is equal to the square of its value multiplied by the resistance of the conductor. Heating the air surrounding a power line wastes energy. And these losses can theoretically be reduced in two ways. The first of them involves reducing the resistance, that is, thickening the wires. The larger the cross-section, the lower the resistance, and vice versa. But I also don’t want to waste metal, it’s expensive, copper after all. In addition, double consumption of conductor material will not only increase the cost, but also make it heavier, which, in turn, will lead to an increase in the complexity of installing high-rise lines. And the supports will need more powerful ones. And losses will only be reduced by half.

Solution

To reduce the heating of wires during energy transfer, it is necessary to reduce the amount of current passing. This is absolutely clear, because reducing it by half will lead to a fourfold reduction in losses. What if ten times? The dependence is quadratic, which means that the losses will be a hundred times smaller! But the power must “pump” the same as that needed by the aggregate of consumers waiting for it at the other end of the power line, sometimes coming from the power plant hundreds of kilometers away. The conclusion suggests itself that it is necessary to increase the voltage by the same amount as the current is reduced. at the beginning of the transmission line is exactly what it is designed for. Wires come out of it under very high voltage, measured in tens of kilovolts. Throughout the entire distance separating a thermal power plant, hydroelectric power plant or nuclear power plant from the populated area where it is addressed, energy travels with a small (relatively) current. The consumer needs to receive power with the given standard parameters, which in our country correspond to 220 volts (or 380 V phase-to-phase). Now we need not a step-up substation, as at the input of power lines, but a step-down substation. goes to distribution devices to keep the lights on in houses and the rotors of machine tools spinning in factories.

What's in the booth?

From the above it is clear that the most important part in a substation is a transformer, usually a three-phase one. There may be several of them. For example, you can replace it with three single-phase ones. A larger number may be due to high power consumption. The design of this device can be different, but in any case it has impressive dimensions. The more power allocated to the consumer, the more serious the structure looks. The design of an electrical substation, however, is more complex and includes more than just a transformer. There is also equipment intended for switching and protecting an expensive unit, and also, most often, for cooling it. The electrical part of stations and substations also contains distribution boards equipped with control and measuring equipment.

Transformer

The main task of this structure is to convey energy to the consumer. Before sending, the voltage must be increased, and after receiving it, reduced to the standard level.

Despite the fact that the circuit of an electrical substation includes many elements, the main one is still the transformer. There is no fundamental difference between the design of this product in a conventional power supply unit for a household appliance and high-power industrial designs. The transformer consists of windings (primary and secondary) and a magnetic circuit made of a ferromagnet, that is, a material (metal) that enhances the magnetic field. Calculating this device is a completely standard educational task for a technical university student. The main difference between a substation transformer and its less powerful analogues, which is striking, in addition to its size, is the presence of a cooling system, which is a set of oil pipelines encircling the heating windings. Designing electrical substations, however, is not an easy task, since it is necessary to take into account many factors, ranging from climatic conditions to the nature of the load.

Traction power

It's not just homes and businesses that consume electricity. Everything is clear here, you need to supply 220 Volts AC relative to the neutral bus or 380 V between phases with a frequency of 50 Hertz. But there is also urban electric transport. Trams and trolleybuses require constant voltage rather than alternating voltage. And different. The tram contact wire must have 750 Volts (relative to the ground, that is, the rails), and the trolleybus requires zero on one conductor and 600 Volts DC on the other, the rubber wheel treads are insulators. This means that a separate, very powerful substation is needed. it is transformed, that is, straightened. Its power is very large, the current in the circuit is measured in thousands of Amperes. Such a device is called a draft device.

Substation protection

Both the transformer and the powerful rectifier device (in the case of draft power supplies) are expensive. If an emergency occurs, a current will appear in the circuit of the secondary winding (and therefore the primary). This means that the cross-section of the conductors has not been calculated. The electrical transformer substation will begin to heat up due to resistive heat generation. If you do not provide for such a scenario, then as a result of a short circuit in any of the peripheral lines, the winding wire will melt or burn. To prevent this from happening, various methods are used. These are differential, gas and overcurrent protection.

Differential compares the current values ​​in the circuit and the secondary winding. Gas protection is triggered when combustion products of insulation, oil, etc. appear in the air. Current protection turns off the transformer when the current exceeds the maximum set value.

The transformer substation should automatically turn off in the event of a lightning strike.

Types of substations

They vary in power, purpose and design. Those that serve only to increase or decrease voltage are called transformers. If changes in other parameters are also required (rectification or frequency stabilization), then the substation is called a converting substation.

According to their architectural design, substations can be attached, built-in (adjacent to the main facility), intra-shop (located inside the production premises) or represent a separate auxiliary building. In some cases when it is not required high power(when organizing power supply to small settlements), a mast structure of substations is used. Sometimes power line supports are used to place the transformer, on which all the necessary equipment is mounted (fuses, arresters, disconnectors, etc.).

Electrical networks and substations are classified by voltage (up to 1000 kV or more, that is, high voltage) and power (for example, from 150 VA to 16 thousand kVA).

According to the schematic basis of external connection, substations are divided into hub, dead-end, pass-through and branch.

Inside the camera

The space inside the substation in which transformers, buses and equipment are located that ensure the operation of the entire device is called a chamber. It can be fenced or closed. The difference between the methods of alienating it from the surrounding space is small. A closed chamber is a completely isolated room, and a fenced one is located behind non-solid (mesh or lattice) walls. They are usually manufactured by industrial enterprises according to standard designs. Servicing of power supply systems is carried out by trained personnel who have access and the necessary qualifications, confirmed by an official document on permission to work on high-voltage lines. Operational monitoring of the operation of the substation is carried out by an electrician or power engineer on duty, located near the main switchboard, which can be located remotely from the substation.

Distribution

There is another important function that the power substation performs. Electrical energy is distributed among consumers according to their standards, and in addition, the load on the three phases should be as uniform as possible. In order for this task to be successfully solved, there are distribution devices. RUs operate on a single voltage and contain devices that switch and protect lines from overload. The switchgear is connected to the transformer by fuses and breakers (single-pole, one for each phase). Distribution devices according to their location are divided into open (located outdoors) and closed (located indoors).

Safety

All work performed in an electrical substation is classified as particularly risky and therefore requires emergency measures to ensure occupational safety. Basically, repairs and maintenance are carried out with complete or partial blackout. After the voltage is turned off (electricians say “removed”), provided that all necessary tolerances are in place, the current-carrying busbars are grounded to prevent accidental switching on. The warning signs “People are working” and “Do not turn on!” are also intended for this. Personnel servicing high-voltage substations are systematically trained, and their skills and acquired knowledge are periodically monitored. Permit No. 4 gives the right to perform work on electrical installations over 1 kV.

The classification of electrical substations and switchgears is based on the terms and definitions established by the relevant GOSTs and regulatory and technical documentation. The main, most frequently used terms and definitions include the following: electrical substation - an electrical installation designed for receiving, converting and distributing electrical energy, consisting of transformers or other electrical energy converters, control devices, distribution and auxiliary devices in accordance with GOST 19431-84 (GOST 24291-90). Substations with transformers that convert electrical energy only by voltage are called transformer stations; and those that convert electricity by voltage and other parameters (frequency change, current rectification) are called converters. Two or more, usually three-phase, transformers can be installed on a substation. The installation of more than two transformers is accepted on the basis of technical and economic calculations, as well as in cases where two medium voltages are used at the substation. In the absence of a three-phase transformer of the required power, as well as due to transport restrictions, it is possible to use a group of single-phase transformers. A substation, as a rule, consists of several switchgear of different voltage levels, interconnected by a transformer (autotransformer) connection; 4.2.10). In a package transformer substation, all high-voltage and low-voltage equipment is installed at the factory, and the substation arrives at the site in finished form, that is, as a kit. Complete transformer substations for indoor (KTP) and outdoor (KTPN) installations are produced with one or two transformers with a capacity of 250 to 2,500 kVA (in KTP) and up to 1000 kVA (in KTPN) at a voltage of 6-10 kV; from 630 to 16,000 kVA (in KTPN) at a voltage of 35 kV. These substations are equipped with protective switching equipment, measuring, signaling and electricity metering instruments and consist of an input block high voltage, power transformer and switchgear 0.4 kV. PTS come in dead-end and walk-through types, as well as various modifications, including: kiosk, cabinet and other types. Dead-end type transformer substations are used to supply power to populated areas and agricultural consumers. Kiosk-type transformer substations (block-type) are used as dead-end transformer substations with a capacity of 250 kVA and higher with equipment serviced from the ground. Such PSs are convenient and safe to maintain; mast transformer substation (MTP) - an open transformer substation, all the equipment of which is installed on a structure (including on two or more overhead line support posts) with a service platform at a height that does not require fencing of the substation (PUE, clause 4.2.11). MTP is constructed on A-, P- or AP-shaped or single-column structures made of reinforced concrete or wooden racks. All substation equipment is mounted on the A-shaped structure: disconnector, fuses, arresters, a single-phase transformer with a power of more than 10 kVA and a 0.23-0.4 kV distribution board. The substation does not have a service platform and stairs. U-shaped structures are used for substations with three-phase transformers with a power of up to 250 kVA inclusive. The transformer is located on the site at a height from the ground of at least 3.5 m. AP-shaped structures are used for substations with transformers with a power of up to 400 kVA. All equipment is mounted on them, including the disconnector. To service the MTP, a platform with railings must be installed at a height of at least 3 m. To climb the MTP, it is recommended to use ladders with a device that prohibits climbing them when the switching device is turned on; pole-mounted transformer substation (STP) - an open transformer substation, all the equipment of which is installed on a single-column overhead line support at a height that does not require fencing (PUE, clause 4.2.11). Structurally, the PS consists of) section of 6-20 kV lines (PUE, clause 4.2.13); chamber - a room intended for the installation of devices, transformers and buses. A closed cell is a cell that is closed on all sides and has solid (not mesh) doors. Fenced chamber - a chamber that has openings protected completely or partially by non-continuous (mesh or mixed) fences (PUE, clause 4.2.14). The prefabricated one-way service chamber (KSO) is a type of switchgear, manufactured according to, has many modifications, is installed only in special electrical rooms and is maintained by trained personnel; busbar system - a device that is a system of conductors, consisting of busbars installed on supports made of insulating material, running in channels, boxes or similar shells (GOST 22789-94); electrical installations, which differ: by purpose - generating, converter-distribution and consumer. Generating electrical installations are used to generate electricity, conversion and distribution electrical installations convert electricity into a form convenient for transmission and consumption, transmit it and distribute it among consumers; by type of current - direct or alternating current; in terms of voltage - up to 1000 V or above 1000 V. The rated voltage scale is limited to a relatively small number of standard values, due to which a small number of standard sizes of machines and equipment are manufactured, and electrical networks are made more economical. In three-phase current installations rated voltage(short circuit) or maximum permissible switched power. In switchgear and substation voltages above 1000 V, the distances between electrical equipment, devices, live parts, insulators, fences and structures are installed so that during normal operation of the electrical installation physical phenomena(heating temperature, electric arc, gas emission, sparking, etc.) could not lead to equipment damage and short circuit. In networks with a voltage of 6-10 kV, distribution points (DP) are widely used, which are an electrical switchgear, not part of the substation (GOST 242910-90), and intended for the distribution of electrical energy within the distribution network. The distribution center consists of busbars divided into sections, a certain number of cells (connections) and a control corridor. The cells are used to house switching and protective equipment: switches, current transformers (CTs) and voltage transformers (VTs), disconnectors, fuses, and protection devices. The RP control corridor is a room in which drives for switches and disconnectors are installed; A service corridor is a corridor along the switchgear chambers or cabinets, intended for servicing devices and buses. reserve (ATS), which is performed on the 0.4 kV side on contactors with a rated current from 600 to 1000 A. Depending on their location, ATS devices can be local (within one substation, for example, an ATS on a sectional switch), or close to it , or network (at various points of the network), which, when triggered, ensure restoration of power to network sections near the substation. n. Dusty rooms are divided into rooms with conductive dust and rooms with non-conductive dust;