Schemes of input-distribution devices (ASU) of residential buildings. Introductory switchgear (ASU). Types and application What is a lie in an electrician decoding

Chapter 7.1. PUE-7. ELECTRICAL INSTALLATIONS OF RESIDENTIAL, PUBLIC, ADMINISTRATIVE AND DOMESTIC BUILDINGS

7.1.3. Input device (VU) - a set of structures, devices and devices installed at the input of the supply line to the building or to its separate part. The input device, which also includes devices and devices of outgoing lines, is called an input-distribution device (ASU).

ASU, UVR- intended for input, accounting and distribution electrical energy, protection of electrical consumers of networks with a voltage of 380/220 V three-phase alternating current with a frequency of 50 Hz in networks with a dead-earthed neutral.
ASU provides line protection against overloads and short circuits and are used for infrequent (up to three to six starts per hour) operational switching of electrical circuits.
ASUs are manufactured in accordance with GOST R 51732-2001, GOST R 51321.1-2000 (IEC 60439-1-92) and TU 3434-003-78539533-05
ASU can be manufactured for use with systems grounding TN-S, TN-C, TN-C-S, according to GOST 30331.2, GOST R 50571.2
ASU is hosted in a specially equipped room (electric switchboard room) directly at the facility.
Type of execution of the ASU - floor, cabinet.
By purpose, the ASU panels are divided into:
- introductory panels or panels with the installation of electricity consumption meters;
- distribution panels;
- panels with AVR.

The main characteristics of the ASU

Are completed from panels of unilateral service and can be single-panel and multi-panel. Metering devices are installed in the panels. If necessary, to control lighting networks common use blocks of automatic and not automatic control lighting. Photo relays or photo relays in combination with time relays were used as command devices.
The busbar can withstand without damage shock short-circuit current of 10 kA.
Bus system VRU-1E: L1, L2, L3, PEN
Tire system VRU-3E: L1, L2, O, N, PE.
ASU panels have rated currents of 63, 100,160, 250, 400, 630A. Input of wires and cables is provided from below and from above, an output - downwards or through the top removable cover.
Direct connection counter (only for version 60 and 100 A).
Transformer inclusion counter.
Current transformers are installed in the ASU, or the installation of meters is located in a separate switchboard.
Rated current, Inom - up to 630A.
Rated insulation voltage, Unom - up to 1000V.
Permissible through short-circuit current, Icw - up to 10 kA (rms).
Rated network frequency, f - 50/60 Hz.

ASU - design features, composition

ASUs are made in the form of a housing with removable side panels, floor-mounted or mounted.
If necessary, ASUs can be assembled in sections.
Typically, the input panels of the ASU consist of an input compartment, this compartment houses a circuit breaker or switch, fuses required amount, a compartment for accounting for the consumption of electrical energy and installation of outgoing lines, current transformers and an electric meter, as well as a box with instrumentation are installed in it.
The electricity metering compartment has a place for sealing.
On the basis of the ASU, input, distribution and sectional devices, metering units can be made.
ASUs made in the floor version and, if necessary, can be equipped with a stand of the desired height.
Enclosures are made of 1.5mm thick sheet steel. Doors are equipped with one or two locks.
Enclosures are manufactured with a degree of protection 1P31 and 1P54.
dimensions ASU (HxWxD): 2000x450x450; 2000x630x450 and others.
The coating of all products is epoxy-polyester powder, color KM 7035 (light gray). Products are packed in three-layer corrugated cardboard.

In the photo, the ASU is assembled, the equipment is manufactured by ABB, on both inputs there are OT125A3 knife switches, automatic switches Tmax 100A, electric meter Mercury 230. On the front panel of the switch control knobs and voltage indication. Installation of the input-distribution cabinet, in the foreground there is a place for installing a reversing knife switch.

Possible designations of input-distributing devices of the VRU-1 series
Purpose of panels:
11-18 - introductory;
21-29 - input distribution;
41-50 - distribution;

ASU order

To order a VRU, the following information is required:

Single line diagram;
Specification for the equipment installed in the ASU (desirable);
The layout plan of the ASU in the switchboard.

To order the manufacture of ASU, you must specify the required number of power inputs, the rated current of the fuse-links, the type of electric meter for direct or transformer connection.
In the order for the production of distribution panels, indicate the number and rated currents of the circuit breakers.
For the manufacture of ASU with full compliance project documentation it is necessary to provide a single-line design scheme or a task for the manufacturer.
For example: It is necessary to make an ASU with the number of inputs 2, with a rated current of fusible links 100/80A, a transformer connection meter, the meter type is induction, a disconnector, IP31 version.

At the entrance to the building, an ASU or VU must be installed. Inside the building, one or several such devices can be installed. If the building has several consumers isolated in the economic part, then it is highly recommended for each of them to install an independent ASU or VU.

ASU allows the supply of consumers who are in different buildings, but provided that they are functionally related. In addition, in this case, it is necessary to strictly comply with the requirements for ensuring a durable contact connection with branch wires.

For air inlet, surge suppressors must be installed.

On the single line diagram of an electrical project, it is forbidden to install additional cable boxes before entering buildings to separate the service area of networks inside the building and external supply networks. Such separation should be carried out in the main switchboard or in the ASP.

Main switchboard, ASU and VU must be equipped with protection devices in all inputs of supply lines and on all outgoing lines. Installation for control devices is also required. On the outlet lines, control devices can be installed either on each line, or be common to several lines.

The circuit breaker can be considered as a control and protection device.

Regardless of the presence of control devices at the beginning of the supply network, the same devices should be installed at the inputs of the supply lines of public utilities, in administrative and commercial premises, as well as in premises that are administratively and economically separated.

The floor shield is installed at a distance of no more than 3 m in length electrical wiring from the supply riser, taking into account the requirements of Ch. 3.1.

Main switchboard, ASU, VU, as a rule, are installed in switchboard rooms, access to which is only for service personnel. In areas that are prone to flooding, these devices are installed above the flood level. Also, these ASU, VU and MSB can be installed in rooms that are located in operated dry basements, provided that they are fenced off with partitions with a fire resistance limit of at least 0.75 hours.

When placing the main switchboard, ASU, VU, group shields, distribution points outside the switchboard rooms, they are placed in places that are convenient for maintenance, in cabinets with a shell protection degree of at least IP31.

Distance between pipelines (heating, water, sewerage, internal drain), gas meters and gas pipelines and installation sites of ASU, VU and MSB should be at least 1 meter.

It is strictly forbidden to place switchboard rooms, main switchboards, ASUs and VUs under bathrooms, toilets, kitchens (exception - kitchens in apartments), shower rooms, washing rooms, washing rooms, steam rooms, washing rooms and other rooms that are connected with water technological processes. An exception may be cases where special measures for additional waterproofing, which prevent the ingress of moisture into rooms with installed switchgear. It is also not recommended to lay pipelines through the switchboard rooms (heating, water supply). And if it is impossible to comply this recommendation ventilation ducts, pipelines, etc. should not have branches within the switchboard (an exception is a branch to heater the room itself), as well as valves, hatches, flanges, gate valves.

It is not allowed to lay pipelines with flammable liquids and gas through electrical panels, as well as sewers and internal drains.

Electrical room doors must open outwards. Also, these premises should be provided with natural lighting and ventilation. The temperature inside should not be lower than + 5C.

© All materials are protected by copyright law of the Russian Federation and the Civil Code of the Russian Federation. Full copying is prohibited without the permission of the administration of the resource. Partial copying is allowed with a direct link to the source. The author of the article: a team of engineers of JSC Energetik LTD

Content:

The main function of the input distribution device is to receive and then distribute the received electricity to individual consumers. These devices provide protection of machinery and equipment from short circuits and emergency overloads. control devices, installed in the input distribution devices (ASU), allow you to take into account the consumed electricity and exercise control over the correct distribution of loads in the network. Most often, ASUs are used in AC networks, at a voltage of 220-380 volts and a frequency of 50-60 Hz with a deaf ground.

What is an input distribution device

Input-distribution devices refer to special electrical equipment in which various devices and devices are installed. With the help of the ASU, electricity is not only received, but also distributed among consumer groups within the facility. They are installed at the input of the supply cable in the building itself or in an extension. If there are several separate inputs in large ladies, it is recommended to install a separate ASU for each of them.

If there are additional buildings on the territory of the main facility, then after the main ASP, you need to install an input-distribution device in each of them. All equipment is installed in special cabinets. Them standard equipment includes the following components:

Copper bars PE andN. The connection of wires to the PE copper bus is carried out with bolts, washers and nuts. For more reliable fastening, special grover washers are additionally used. To carry out this work, it is imperative to use an electric or mechanical tool. The PE bus must be equipped with places for connecting all the necessary conductors - introductory PEN, grounding and others. Zero working conductors of the home are connected to the copper bus N. electrical network.

Automatic input or fuses combined in a group. Designed to connect the input power cable. Its value is selected in accordance with the design of the power supply system. The introductory circuit breaker protects home electrical wiring from overloads, short circuits, deliberate power outages before network maintenance.

Surge arresters or voltage limiters. Their installation is carried out after the introductory machine. These devices connect phase wires with protective rail PE. In the event of overloads, the arresters are triggered. Hits the PE bus phase voltage, which leads to the operation of the ASU protection.

Block of automatic distribution networks for individual groups. The main function of these devices is the distribution of electricity into groups. Each group corresponds to the kitchen, bathroom, rooms, lighting system and other consumers and requires a separate circuit breaker. If necessary, additional devices can be installed protective shutdown. The installation must ensure even distribution of the load between the phases. The number of machines for each phase is calculated taking into account the demand factor, which determines the probability of the maximum load of all electrical networks.

Wires and type-setting terminal blocks for switching in ASU. Each wire must have its own color: red - phase wires, blue - wire N, yellow-green - PE. The ends of the wires in internal networks are marked with special inscriptions. Phase tires are recommended to be painted in different colors or label as L 1 , L 2 , L 3 . Each wire must be insulated for a voltage of 660 V. When entering the ASU, they are protected by bushings.

In addition to the main instruments and equipment, a metering unit is placed in the input-distributing device, which includes a meter for metering the consumption of consumed electrical energy.

Appointment of the ASU

The electrical energy entering the apartment is distributed and controlled by various devices. With the help of an input-distributing device, they are grouped into small space, and all together form a single whole. Thus, input-distributing devices are a set of devices and equipment for various purposes placed in a common closet. Depending on the size and purpose, a certain number of transformers, automatic machines, meters, and other devices can fit in each cabinet.

The main purpose of the ASU is to supply buildings or separate parts premises with electricity. They consist of panels that open from one side only, so their maintenance is one-way. There are one-, two- and three-panel designs. Sometimes four-panel options go on sale. Some models of input distribution devices are placed in special containers. Such shields are reliably protected from negative influences. environment, moisture and dust do not get inside.

The main functions of the ASU are as follows:

Distribution of electrical energy for all residential and non-residential facilities.
These devices unite all protective and control equipment, devices for measuring and accounting for consumed energy in one place.
In many designs, additional circuit breakers are installed to protect the electrical network of the facility from overloads and short circuits.
With the help of the ASP, power is quickly turned on and off from individual parts of buildings, devices and equipment.

Types of input distribution devices

There is its own classification of input-distribution devices. First of all, they are divided according to the rated current 250, 400 and 630A, as well as the size and number of built-in control and protection devices. Some models have automatic energy switches, lighting control devices, as well as special places for mounting electricity meters.

Depending on the purpose and design features, all switchboards are divided into different kinds and categories:

Main switchboard (MSB). Refers to power high-voltage installations. At its core, it is a high-tech mechanical or electronic system that provides the object with electrical energy.
Input distribution device. It consists of a whole complex of apparatus, instruments and equipment. Used for receiving, distributing and metering electricity. It is a metal case in which replaceable panels are installed.
Distribution boards. They take part in the direct distribution of electricity, provide consumer protection from overcurrents and short circuits. Installed in residential and public buildings.
Control and automation boards. They are used in automated systems: fire, lighting, ventilation and others.
Accounting boards. Used in conditions industrial production for electricity metering in three-phase networks. In residential buildings and offices are used very rarely.

If necessary, the devices may provide additional places for the installation of circuit breakers and RCDs. Models using fuses will not only protect against voltage surges, but also provide a quick shutdown of current in different places and premises. If, however, it is difficult to choose a particular option, you can make a layout from several types of panels. As a result, you will get a universal input-distribution device that meets all the necessary requirements.

Installation and connection of the input switchgear

Installation of input distribution devices is carried out according to the electrical diagram, in accordance with which all actions are performed in a certain sequence. Violation of the procedure is completely unacceptable in connection with the requirements of electrical safety.

At the very beginning of work, the object is disconnected from the power source and completely de-energized. After that, the input power cables are disconnected, the electrical equipment and the ASU are dismantled, to be replaced. Next, the installation of new input-distribution devices is carried out. For right choice fasteners have an approved scheme. Then the cable is laid and all the cores are sealed. Power wires are brought in and fixed on new electrical equipment, input cables connected to the central switch or to other types of disconnecting devices. Collected circuit diagram tested, and all its elements are marked. After that it is executed.

These electrical installation works cannot be trusted to individuals or non-specialized organizations. Poor performance of operations can lead to accidents, accidents and other negative consequences. The most characteristic violations of unskilled workers are the incorrect connection of the wire cores in the clamps and the installation of electrical equipment. During the installation process, the insulation of cables and wires is often violated, the ground circuits are broken, the cores in the protective equipment are not sufficiently clamped.

All this can be avoided by involving only qualified specialists in the work. Only they at the end electrical work everything will be done qualitatively necessary measurements to exclude or identify possible violations. Based on the results of the measurements, a technical report is drawn up.

This check starts with visual inspection all assembled circuit and its individual elements. Grounding measurements are made without breaking the circuit of grounded installations. The quality of the insulation is checked, its resistance is measured. Also, the impedance of the phase-zero loop is measured, the circuit parameters are checked and specifications protective equipment, confirmation of the continuity of protective conductors. The circuit breakers are checked for current tripping. All these measures guarantee reliable and high-quality operation of input-distributing devices, their performance of all functions in full.

ASU standards

General specifications for input-distributing devices are defined interstate standard GOST 32396-2013. This document provides for the regulatory support of all technical issues affecting the ASU. AT without fail modern regulatory requirements to electrical installations of objects of various heights, as well as IEC standards relating to electrical and fire safety.

This standard contains the following items related to ASU:

Requirements for devices used in buildings with different heights, in private houses and cottages, regarding the possibility of their connection to four- and five-wire supply networks with.
Classification of ASU by the presence or absence of equipment for data retrieval at a distance, as well as remote control and automatic control of power consumption modes.
Requirements for ASUs installed in places with free access to them for unqualified personnel.
In private houses and cottages, ASUs are installed, equipped with two methods of protection against electric shock.

The scope of this standard affects the input and distribution devices that receive, meter and distribute energy in electrical installations of residential and public buildings. The document provides for the protection of distribution and group circuits extending from the ASU during overloads and short circuits. If necessary, these devices can be manufactured in a different climatic version, designed for more severe operating conditions.

In order to properly understand the various power supply schemes for residential buildings, you need to know about the three categories of ensuring the reliability of the power supply of electrical installations. The simplest category is the third. It provides for the power supply of a residential building from a transformer substation through one electric cable. At the same time, in the event of emergency interruption in the power supply of the house should be less than 1 day.

With the second category of power supply reliability, a residential building is powered by two cables connected to different transformers. In this case, if one cable or transformer fails, the power supply to the house for the time of troubleshooting is carried out through one cable. A break in the power supply is allowed for the time necessary for the on-duty electrical personnel to connect the loads of the whole house to a working cable.

There are two types of home power from two different transformers. Either the loads of the house are evenly distributed over both transformers, and in emergency mode connected to one, or one cable is used in the operating mode, and the second is a backup. But in any case, the cables are connected to different transformers. If in switchboard at home two cables are laid, one of which is a reserve one, but it is possible to connect these cables to only one substation transformer, then we have only the third category of reliability.

With the first category of power supply reliability, the residential building is powered by two cables, as well as with the second category. But when a cable or transformer fails, the loads of the whole house are connected to a working cable using a device automatic start reserve (AVR).

There is a special group of electrical receivers (smoke removal systems in case of fire, evacuation lighting and some others), which must always be powered according to the first category of reliability. To do this, use backup power sources - rechargeable batteries and small local power plants.

According to existing standards for the third category of reliability, electricity is supplied to houses with gas stoves no more than 5 floors high, houses with electric stoves with less than 9 apartments in the house and houses of gardening associations.

Houses with gas stoves with a height of more than 5 floors and houses with electric stoves with more than 8 apartments are subject to electricity supply according to the second category of reliability.

According to the first category of reliability, it is mandatory to supply heat points with electricity apartment buildings, in some houses and elevators. It should be noted that in the first category, electricity is mainly supplied to some public buildings: these are buildings with more than 2,000 employees, operating rooms and maternity wards of hospitals, etc.

The figure shows a power supply diagram for a four driveway house, powered by the second category of reliability with a backup cable. The switching of the supply cables is carried out by a reversing knife switch having positions "1", "0" and "2". In position "0" both cables are disabled. The circuit breakers QF1….QF4 power the lines that run along the access vertical risers, from which the power is taken to the apartments. General household loads: lighting of stairs, basements, lamps above entrance doors the entrances are fed by a separate group containing its own electricity metering.

Rice. 1. Power supply scheme of an apartment building

Depending on the number of apartments in the house, all electrical equipment can be placed in one electrical cabinet or in several. What the electrical equipment of switchboard residential buildings looks like is shown in the photographs. On photo 1 - input devices and accounting units. In photo 2 - a reversing knife switch with fuses. In photo 3 - circuit breakers on outgoing lines.

If the school had a subject: “The basics of the power supply of our home”, then accidents caused by the failure of various power switches and disconnectors on power lines and in transformer substations would have happened much less frequently. From childhood, we are taught to wash our hands before eating and are told how to cross the road correctly. But no one teaches us that if the lights go out in the apartment, then all powerful electrical appliances should be immediately disconnected from the network: irons, heaters and electric stoves.

For example, if a power outage occurred as a result of a blown fuse in the electrical panel of a house, then in order to restore power supply, electricians will need to turn off the breaker, replace the fuse, and turn the breaker back on. The "life" of all switching devices depends very much on the magnitude of the switched load.

If all the residents of the house disconnected their electrical appliances from the network during a power failure, then such inclusions would occur at much lower currents and the circuit breakers would last much longer.

In our example, when electricians turn off the breaker, then in a two-phase circuit with unburned fuses, at the moment the contacts are disconnected, a bright flash can be observed - an arc will flash for a fraction of a second, from which the contacts will gradually burn out.

First, let's understand the terminology. In any electrical installation there are devices for the input and distribution of electricity. Often these devices are combined into one input-distribution device, which is a cabinet or shield, consisting of separate panels. Usually these are input, distribution panels and ATS panels. From here follow various titles such a device, such as VRShch, MSB, VU. The issue of replacing the input-distribution device at the facility will inevitably arise, regardless of the operating conditions. With competent maintenance the replacement of ASU elements occurs gradually as the equipment fails, but even with this approach it is not possible to avoid a one-time overhaul. This is due both to the natural aging of wire and cable sheaths, and the need to modernize the design and layout of the ASU. After 20-25 years, the ASP configuration becomes so obsolete that it is easier to dismantle and discard the ancient equipment than to repair it. The industry does not stand still and constantly offers new compact modern solutions for input distribution devices.

So, the first thing to start with is the manufacture of a single-line design diagram of an electrical installation. It must be borne in mind that long time operation, the original power supply scheme, most likely, has undergone major changes. You can’t just order a copy of the original ASP, as the design standards and the object loads themselves have changed. Only having on hand current scheme ASU according to the actual state of the electrical installation, you can proceed to the design of a new ASU, which will take into account all additional loads. By finished scheme at the factory or in a specialized organization, you can order ASU. Only a certified organization can manufacture ASU, since when applying voltage, it is necessary to present certificates for ASU. It will also save the customer from marriage and manufacturing errors. The production of an ASP usually takes two to four weeks. Production time depends on the components used. When using imported components, there may be a delay in their delivery through the dealer.

In parallel with the order of the ASU, it is necessary to think about a temporary power supply scheme. If the power of the electrical installation is large, then the replacement of the ASU may take several work shifts. Naturally, all work on the replacement of the ASU is carried out with the voltage turned off. For the period of work, if necessary, a temporary power supply scheme from a diesel generator or other source is activated. Such a need exists for consumers of the first category of reliability, such as hospitals, engineering facilities, manufacturing enterprises with continuous cycle. In practice, server rooms and stores with freezing equipment are added to such facilities. Usually, if there is no need for a backup circuit, then the installation of a new ASU takes place at night or on weekends. To de-energize the ASU, it is necessary to turn off the breaker or circuit breaker at the point of attachment or at the nearest possible location from the ASU. Often power outage is only possible in a transformer substation. If the substation is on the balance sheet of the electric grid company, then the shutdown must be agreed in the operational area to which the transformer substation belongs.

After installing new equipment, it must be energized. Electricity meters are installed at the input, which must be sealed by a representative of Energosbyt. For this, the ASU scheme is being coordinated in Energosbyt. In this case, the energy supply contract does not need to be renegotiated. New meter numbers are simply entered into the contract. For technical accounting, sealing of meters is not required. It must be remembered that Energosbyt must be notified of the removal of seals from the meters before the start of work, and not after. Unauthorized removal of seals will entail a large fine, since the question will arise how long ago the seals were removed. With the seals removed, the consumer has the opportunity to receive electricity bypassing the meter. The fine can be calculated based on the maximum round-the-clock consumption for six months.

Replacing the ASU is a complex and lengthy procedure of increased danger. In the process of replacing the ASU, there is a high probability of being fined. In the event of unplanned downtime during the installation of the ASU, all activities of the enterprise can be stopped. Entrust the replacement of ASU to professionals!

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