Maintenance of switchgears. Safety rules for operating switchgears Design of a workplace for repairing switchboards

One of the main tasks of operating switchgears is maintaining the necessary reserves for dynamic and thermal stability, throughput, and voltage levels in the device as a whole and in its individual elements. These tasks can be achieved with proper maintenance of switchgears. During maintenance, switchgear devices are inspected, and during routine repairs, noticed faults that require disassembling the equipment are eliminated. Current repairs are carried out at the installation site of the equipment, while faulty parts are replaced, and after their replacement, switchgear devices are adjusted and tested.

Frequency of inspections of switchgears. The frequency of inspection is determined depending on the type of device, its purpose and form of maintenance. Approximate inspection times are as follows:

in switchgears serviced by shift personnel on duty at the substation itself or at home - daily. In case of unfavorable weather (wet snow, fog, heavy and prolonged rain, ice, etc.), as well as after short circuits and when a signal about a ground fault appears in the network, additional inspections are carried out. It is recommended to inspect the device in the dark once a week to identify possible corona discharges in areas of insulation damage and heating of live parts;

in switchgear substations with voltages of 35 kV and above that do not have permanent personnel on duty, the inspection schedule is drawn up depending on the type of device (closed or open) and the purpose of the substation. In this case, inspections are performed by the head of the substation group or a foreman at least once a month;

transformer substations and distribution devices of electrical networks with a voltage of 10 kV and below that do not have

duty personnel are examined at least once every six months;

extraordinary inspections at facilities without permanent staff on duty are carried out within the time limits established by local instructions, taking into account capacity short circuit and equipment condition. In all cases, regardless of the value of the short circuit interrupted power, the circuit breaker is inspected after a cycle of unsuccessful automatic reclosing (AR) and tripping due to a short circuit.

All faults noticed during inspections of switchgears are recorded in the operational log. Malfunctions that disrupt normal operation must be eliminated as soon as possible. The serviceability of backup elements of switchgear devices (transformers, switches, busbars, etc.) must be regularly checked, including them under voltage within the time limits established by local instructions. Backup equipment must be ready to be turned on at any time without any prior preparation. The frequency of cleaning switchgears from dust and dirt depends on local conditions. It is installed by the chief engineer of the enterprise.

Switch maintenance. External inspections of oil switches without shutdown are carried out taking into account local conditions, but at least once every six months, together with inspections of the switchgear. During inspections, the following is checked: the condition of the insulators, fastenings and contacts of the busbar, the oil level and the condition of the oil indicators; no oil leakage from the grid contacts of low-volume switches or through the gaskets of tank switches. The oil level of switches largely determines the reliability of their operation. It should not go beyond the oil indicator at ambient temperatures from -40" to +40 ° C. Increased oil level in the poles and correspondingly reduced volume air cushion above the oil lead to excessive pressure in the tank when the arc is extinguished, which can cause destruction of the circuit breaker.

A decrease in oil volume also leads to destruction of the switch. It is especially dangerous in small-volume circuit breakers VMG-10, VMP-10. If the leak is significant and there is no oil in the oil sight glass, then the switch is repaired and the oil in it is replaced. In this case, the load current is interrupted by another switch or the load at this connection is reduced to zero. Abnormal heating of the arcing contacts of small-volume switches causes darkening and a rise in the oil level in the oil indicator glass, as well as a characteristic odor. If the temperature of the circuit breaker tank exceeds 70 °C, the circuit breaker should be repaired.

In areas with a minimum temperature below 20 °C, switches are equipped with automatic devices for heating the oil in the tanks. It is recommended to check the circuit breaker drives at least once every three (six) months. If there is an autorecloser, it is advisable to test for shutdown from relay protection with shutdown from the autorecloser. If the switch fails to operate, it must be repaired.

During an external inspection of air circuit breakers, attention is paid to its general condition, the integrity of the insulators of the suppression chambers, separators, shunt resistors and capacitive voltage dividers of the support columns and insulating braces, as well as the absence of contamination of the surface of the insulators. Using pressure gauges installed in the distribution cabinet, the air pressure in the tanks of the circuit breaker and its supply to the ventilation are checked (for circuit breakers operating with automatic reclosure, the pressure should be in the range of 1.9...2.1 MPa and for circuit breakers without automatic reclosure - 1, 6...2.1 MPa). The switch control circuit provides an interlock that prevents the switch from operating when the air pressure drops below normal.

During the inspection, they also check the serviceability and correctness of the readings of devices signaling the on or off position of the switch. Pay attention to whether the dampers of the exhaust visors of the extinguishing chambers are securely closed. Visually check the integrity of the rubber gaskets in the connections of the insulators of the extinguishing chambers, separators and their support columns. They control the degree of heating of bus contact connections and hardware connections. When operating air circuit breakers, accumulated condensate is removed from the tanks 1-2 times a month. During the rainy season, the air supply for ventilation increases; when the ambient temperature drops below minus 5 °C, electric heating is turned on in control cabinets and distribution cabinets. At least twice a year, the functionality of the switch is checked by means of control tests for turning off and turning on. To prevent damage to the switches, check and tighten the bolts of all sealing connections 2 times a year (in spring and autumn).

Maintenance of complete switchgears. The operation of complete switchgears (SGD) has its own characteristics due to the limited overall dimensions of the cells. To protect personnel from accidental contact with live parts that are energized, the switchgear is provided with a lock. In stationary switchgear, screen doors are blocked, which are opened only after the circuit breaker and connection disconnectors are turned off. The withdrawable switchgear has automatic shutters that block access to the compartment of fixed disconnecting contacts when the trolley is rolled out. In addition, there is an operational lock that protects personnel when performing erroneous operations. For example, rolling out the trolley into the test position is permitted by blocking only after the circuit breaker is turned off, and rolling the trolley into the working position is permitted when the circuit breaker and grounding knives are turned off. Equipment is monitored through observation windows and mesh fences or inspection hatches covered with a protective mesh.

Inspections of switchgear without shutting them down are carried out according to schedule, but at least once a month. During inspections, the operation of lighting and heating networks and switchgear cabinets is checked; condition of switches, drives, disconnectors, primary disconnecting contacts, locking mechanisms; contamination and absence of visible damage to the insulators; state of secondary switching circuits; operation of switch control buttons. Systematically, depending on local conditions, clean the insulation from dust and contamination, especially in outdoor switchgear (KRUN). When inspecting complete switchgear devices KRU and KRUN, pay attention to the condition of the seals at the joints of metal structure elements; serviceability of equipment connection to the ground loop; availability of safety and fire extinguishing equipment; operation and serviceability of heating devices for KRUN cabinets; presence, sufficiency and normal color of oil in switches; condition of installation connections; heating of live parts and devices; absence of extraneous noise and odors; serviceability of alarms, lighting and ventilation. Simultaneously with the inspection, the correct position of the switching devices is checked. The equipment built into switchgear and switchgear switchgear is inspected in accordance with the operating instructions.

When operating switchgear, it is prohibited to unscrew the removable parts of the cabinet, lift or open automatic curtains if there is voltage in those places to which access is blocked by them. In withdrawable-type switchgear cabinets, to ground outgoing lines using disconnectors built into the switchgear, you need to do the following: turn off the switch, roll out the trolley, check the absence of voltage on the lower disconnecting contacts, turn on the grounding switch, put the trolley in the test position.

The fuses in the auxiliary transformer cabinet can only be changed when the load is removed. When carrying out work inside the compartment of a roll-out cart on an automatic curtain, it is necessary to hang warning posters: “Do not turn on! People are working", "High voltage! Life threatening!" Only trained operating personnel can roll out the trolley with the switch and install it into the operating position.

It is allowed to roll the trolley into the working position only when the grounding switch is in the open position.

Maintenance of disconnectors. When adjusting the mechanical part of three-pole disconnectors, check the simultaneous activation of the knives. When adjusting the moment of contact and compression of the movable knives, they change the length of the thrust or stroke of the limiters and thrust washers, or slightly move the insulator on the base or the jaws on the insulator. When fully switched on, the knife should not reach the contact pad stop by 3-5 mm. The minimum force of pulling one knife from a fixed contact should be 200 N for disconnectors with rated currents of 400...600 A and 400 N for disconnectors with rated currents of 1000...2000 A. The tightness of the contacts of the disconnector is controlled by the resistance to direct current, which should be in within the following limits: for RLND disconnectors (35...220 kV) for rated current 600 A - 220 μOhm; for other types of disconnectors for all voltages with a rated current of 600 A - 175 μOhm, 100 A - 120 μOhm; 1500-2000 A - 50 μOhm.

During operation, the contact surfaces of the disconnectors are lubricated with neutral petroleum jelly mixed with graphite. The rubbing parts of the drive are coated with antifreeze lubricant. The condition of disconnector insulators is assessed by insulation resistance, voltage distribution on the steel elements of pin insulators or by the results of testing the insulator with increased power frequency voltage.

The drive block contacts, intended for signaling and blocking the position of the disconnector, must be installed so that the signal to turn off the disconnector begins to operate after the knife has passed 75% full speed, and the signal to turn on is not earlier than the moment the knife touches the fixed contacts.

Maintenance of short circuiters and separators. Short circuiters are devices designed to artificially create a short circuit in cases where the current in the event of a fault in the transformer may be insufficient to trigger the relay protection. The short-circuiter is switched on automatically by an automatic drive when the relay protection is triggered, and is switched off manually.

When disconnecting power transformers without load, as well as automatically disconnecting damaged transformers, separators are used. The separator can be turned off automatically or manually; it can only be turned on manually using a removable handle. At 35...11O kV connections with separators and disconnectors installed in series, switching off the magnetizing current of transformers and capacitive currents of the line should be carried out by separators. Separators rated at 35 kV allow disconnection of ground fault current up to 5 A.

On average, for 10 km of a 35 kV overhead line, the charging current is 0.6 A and the ground fault current is 1 A.

Short circuits and separators are inspected at least 2 times a year, as well as after emergency shutdowns. During examinations Special attention pay attention to the condition of insulators, contacts, and the grounding wire passed through the window of the current transformer. If traces of burning are detected, the contacts are cleaned or replaced. The duration of movement of the moving parts of a short-circuiter for voltages of 35 and 110 kV from the application of a pulse to closing the contacts should be no more than 0.4 s, and the duration of movement of the separator from the application of a pulse to the opening of the contacts should be 0.5 and 0.7 s, respectively.

During the operation of short circuiters and separators, special attention should be paid to the most unreliable components: open or insufficiently protected from possible contamination and icing springs, contact systems and hinge joints, as well as unprotected bearings protruding from the rear side.

When setting up the short circuit and separator, pay attention to the reliable operation of the separator blocking relay (BRO), which is designed for currents of 500...800 A. Therefore, for short circuit currents less than 500 A, the grounding bus should be replaced with a wire and passed through the current transformer several times . If this is not done, the BRO relay will tighten the armature indistinctly and thereby release the locking mechanism of the separator drive until the short circuit current is turned off. Premature shutdown of separators is one of the reasons for their destruction.

Current repairs of disconnecting devices, as well as checking their operation (testing), are carried out as necessary within the time limits established by the chief engineer of the enterprises. The scope of work on current repairs includes: external inspection, cleaning, lubrication of rubbing parts and measurement of contact resistance to direct current. Unscheduled repairs are carried out in the event of detection of external defects, heating of contacts or unsatisfactory insulation conditions. Adjustment of the short-circuiter and separator consists of checking the operation of the drive for turning on and off, checking the position of the knives and the installation of the tripping spring of the drive with the blocking relay BRO, adjusting the stroke of the cores of the electromagnets and relays.

Monitoring the condition of live parts and contact connections. The condition of live parts and contact connections of busbars and switchgear devices is checked during inspections. The heating of detachable connections in closed switchgears is controlled using electric thermometers or thermal candles and temperature indicators. The operation of an electric thermometer is based on the principle of measuring temperature using a thermistor glued to the outer surface of the sensor head and covered with copper foil. The heating temperature of contact connections is determined using a set of thermal candles with different melting temperatures. Reversible, reusable films are used as thermal indicators, which change color when heated for a long time. The thermal indicator must withstand, without destruction, at least 100 color changes during prolonged heating to a temperature of 110 °C.

Maintenance of grounding devices. During operation, inspections, periodic checks and tests of grounding devices are performed in accordance with the recommendations of the PPR.

In areas of grounding devices subject to intense corrosion, more frequent measurement intervals are established. Unscheduled measurements of the resistance of grounding devices are carried out after their reconstruction or major repairs. The resistance of grounding devices is measured with special devices MS-08, M-416, F4103 or by the ammeter-voltmeter method. Schematic diagrams for switching on the MS-08, M-416, F4103 devices are shown on the covers of the devices or in the instructions. Metal rods with a diameter of 12...16 mm are used as auxiliary grounding conductors, which are driven into the ground to a depth of 0.5 m at a distance specified in the instructions.

SCHEMETECHNOLOGICALREPAIR PROCESSTRANSFORMER

The most vulnerable and often damaged part of a transformer is its HV and, less commonly, LV windings. Damage most often occurs due to a decrease in the electrical strength of the insulation on any section of the winding.

In transformers, bushings, switches, covers and other parts may also be damaged. The approximate ratio of damage to individual parts of the transformer is as follows:

windings and conductive parts - 53%;

switches -12%;

all other parts taken together - 17%.

Studies of the causes of emergency transformer failures have shown that accidents usually occur due to unsatisfactory maintenance and poor quality of repairs.

A transformer with damaged windings or other parts must be immediately taken out of service and repaired. The enterprise draws up an acceptance certificate with a list of defects attached and places an order. The documents record the order number, passport data, customer requirements, results of external inspection, verification tests and measurements. All defects discovered during the further process of disassembling the transformer are also recorded in the list of defects. Based on these data, the volume of repair work is determined.

The most common process flow diagram for repairing three-phase oil-cooled transformers in electrical repair shops of most enterprises is shown in Figure 16.1.

In accordance with this scheme, a damaged transformer, located in a warehouse of faulty transformers, enters the fault detection and preparation department, which consists of three sections - disassembly and washing, diagnostics of windings and the mechanical part of the transformer. At the disassembly site, the transformer is cleaned, the oil is drained from its expander, tank and oil-filled bushings, and then, having been convinced from the records in the accompanying documents and from preliminary tests that the transformer is malfunctioning, they proceed to its disassembly.

Damage to the external parts of the transformer (conservator, tank, fittings, outer part of the inputs, breakdown fuse) can be detected by thorough inspections, and damage to the internal parts - by various tests. However, test results do not always allow us to accurately establish the actual nature of the damage, since any deviation from the norm revealed as a result of tests (for example, increased no-load current) can be caused by various reasons, including a turn short circuit in the winding, the presence of a closed current loop through tightening bolts and pressing parts, incorrect connection of parallel windings, etc. Therefore, during the diagnostic process, as a rule, the transformer is disassembled and, if necessary, the active part is lifted, which allows not only to accurately determine the causes, nature and extent of damage, but also to determine those required to repair the transformer materials, tools and equipment, as well as time.

DISASSEMBLYANDDEFINITIONFAULTS

The sequence of disassembly operations in each case depends on the design of the transformer to be repaired. Modern transformers of domestic production, differing in power and design, and transformers produced in previous years, as well as those produced in the past and currently supplied by foreign companies, are being repaired; therefore, it is recommended to recommend any unified technological sequence for performing disassembly and repair operations of all incoming transformers impossible.

Before disassembling, check the completeness of the transformer received for repair (all assembly units and parts required for this design must be available), as well as the connection of its external parts, the integrity of the welds and connections, and the absence of oil leakage from the flange connections of the fittings to the tank.

First stage of disassembly. Disassembly begins with the removal of the gas relay, thermometer, expander, safety pipe and other devices and parts located on the transformer cover.

Having removed the relay, safety pipe and expander, disassembly continues, moving on to dismantling the transformer cover, which is carried out in compliance with precautions to prevent damage to the porcelain parts of the inputs of the HV and LV windings. The bolts removed from the entire perimeter of the cover, together with the washers put on them and the nuts screwed onto their threads, are washed, coated with anti-corrosion lubricant and, placed in boxes, stored for reuse when assembling the transformer.

The cover, freed from bolts, is slung using lifting eyes screwed onto the threaded ends of the lifting pins protruding from the cover and secured to the yoke beams of the upper yoke of the magnetic circuit. Transformers with a power of up to 4UU kV A usually have two lifting eyes; those of higher power have four. To lift the active part, special devices and slings are used that are designed for the weight of the load being lifted and have passed the necessary tests. When dismantling radiators and other large parts of an outdoor transformer, a truck crane is used as a lifting mechanism.

When lifting the active part of transformers with inputs located on the walls of the tanks, first disconnect the taps and dismantle the inputs, and then lift the active part of the transformer. The active part, lifted from the tank, is installed on a strong platform made of planed boards or on wooden beams so as to ensure its stable vertical position and the possibility of inspection, testing and repair.

Continuing disassembly, disconnect the taps from the inputs and the switch and check the condition of their insulation, the reinforcing seams of the inputs and the contact system of the switch (all noticed faults are recorded). Next, unscrew the eyelets from the vertical studs, remove the cover, take it to the side and lay it so that the gaps protruding under the cover are not damaged; the entries are protected from mechanical damage by covering them with rigid cardboard cylinders or wrapping them in clean burlap.

Second stage of disassembly, the most complex and labor-intensive, is the dismantling of the windings, the main operations of which are performed in the following sequence: remove the vertical studs, unscrew the nuts of the coupling bolts and remove the yoke beams of the magnetic circuit, loosen the upper yoke of the magnetic circuit, tying and arranging the packages of plates in the order in which they will be more convenient lay when mixing the upper yoke. Next, disassemble the connections of the windings, remove the taps, remove the wooden and cardboard parts of the wedging of the HV and LV windings and remove the windings from the rods manually (windings of a transformer with a power of up to 63 kVA) or using a lifting mechanism (windings of transformers with a power of 100 kVA and above) - first HV , and then NN.

After disassembling the transformer, inspect its external part. At the same time, check the cleanliness of the windings, paying special attention to the channels between the windings and the magnetic core. Identify by touch the places where the turns are weakened. In these places, as a rule, the winding insulation is damaged, charred as a result of interturn short circuits that are invisible from the outside. They check by external inspection the condition of the insulation, the absence of deformations and displacement of the windings or its turns, the presence of insulating gaskets, wedges, and spacers.

For installation of any type of distribution board - both power and used for lighting, similar components are used. These are: automation, terminal bars (one for grounding - PE, one for the “pure” neutral and one for each difrel). You also cannot do without NSVI (insulated pin sleeve lugs) and cable ties (plastic clamps) in the case of using jumpers made of stranded wire.

It is best to purchase everything you need in specialized online stores that are ready to provide certificates of compliance of their products with current standards and a guarantee. Moreover, automation and terminal bars should be purchased exactly in the required quantity, but it is recommended to order lugs and cable ties with some reserve, since errors during the installation process are possible that will require rework.

Which company's equipment is preferable? Today, the production of high-quality automation is concentrated in Europe. Some of the most popular premium products are devices from the brands Legrand, Siemens, and ABB. Russian products are considered to be significantly more affordable, although only slightly inferior in quality. trademark IEK (InterElectroKomplekt).

Installation process

1. First, it is recommended to install all automation/protection devices and terminal blocks on DIN rails, achieving optimal location each element. When installing terminal blocks in ceramic block, care should be taken due to the increased fragility of the latter.
2. Then flexible jumpers are prepared and connected. In household electrical panels with 40-50 A automation, the latter are pieces of insulated wire PV-3 (6 mm2), onto the ends of which NShVI is pressed. When preparing jumpers, it is necessary to take into account the color of the insulation - brown or black are usually used for phase connections, and blue or white for neutral lines. To ensure that the wires are securely held inside the control panel and are easily visible, it is recommended to secure them with cable ties.
3. Next, you can begin connecting the input cable. You should first make sure that there is no voltage on its wires. If there is one, disconnect the cable, taking all precautions to avoid electric shock during the connection process - hang a sign “People are working” on the control machine/switch, appoint an observer. Then connect the conductors to the corresponding terminals of the electrical panel - phase and neutral to the main circuit breaker (which must be in the off position), and grounding to the corresponding terminal block.
4. All that remains is to connect the consumers, taking into account where the wire is laid from and its color. Phase wires, which in cables such as VVG, ShVVP, PVS and the like are usually marked with black, grey, brown or red insulation, are connected to the lower terminals of single-pole circuit breakers. Neutrals - blue or white - to the zero buses corresponding to the group, and ground wires - yellow-green, green or yellow - to the PE bus.

Initial assembly and tightening of contacts can be carried out using a cordless electric screwdriver - this can save a lot of effort and time. But after completing the installation operations, it is necessary to tighten it manually, using the most suitable screwdriver for each specific connection. It is also necessary to remember that in the first weeks, as a result of electrothermal effects, the contacts are weakened and after approximately one month after the start of intensive use, it is necessary to check the reliability of each connection and, if necessary, tighten it. In the future, it is enough to perform a similar procedure once every six to twelve months.

If you still have any questions regarding the ShchR installation technology, you can look at one of the many profile videos available on the Internet.

Checking the operation of the control panel

The price for installing a distribution cabinet includes checking the functionality of the electrical installation. It is done by massively (sequentially) turning on all possible consumers, after which it is necessary to walk around the entire facility, checking each outlet using some known working portable electrical appliance. If the automation does not turn off the power to the line at any stage, it means that the installation was carried out correctly.

Then you need to observe the control panel in full load mode for some time. If there is sparking, smoke, a crackling sound is heard, or a burning smell is felt, this indicates unreliable contact in one of the connections, causing overheating, or a malfunction of the automation device that needs to be replaced.

In the absence of the above phenomena, it is recommended to check the functionality of the main components that ensure the safe operation of the internal electrical system - the RCD. For this purpose it is used special tester, creating leaks of a standardized value (10, 30, 300 mA). The price of this device is quite affordable even for a private master. Some models are equipped with their own control button, which, when pressed, should instantly turn off the device.

How much does it cost to install a control panel?

The estimate for the installation of an electrical panel directly or indirectly reflects the following factors: the complexity of the circuit, the number of panel elements and the number of connections that need to be made.

The main task proper organization the electrician's workplace - to ensure his safety by protecting the technician from accidentally touching exposed live parts during the process of assembling, disassembling or checking the equipment being repaired. However, there is another aspect - ergonomics. After all, if necessary tool at hand, then the work will go much faster. Today we will try to understand how to organize everything conveniently and safely.

Characteristics of an electrician's workplace: general information

The first thing you need to pay attention to is neatness, cleanliness, and the absence of foreign objects under your feet and nearby. It is this factor that often causes damage electric shock. The employee stumbles, begins to fall and involuntarily grabs onto any object, trying to hold on. If it turns out to be a bare wire, the consequences can be very dire.

The next aspect is attention to detail. Having disconnected the contacts, the installer checks the presence of current in each of the phases, after which he forgets to remove the voltage and continues to work in the electrical panel. In this case, a slight loss of current can result in an electric shock.

Very important requirement The organization of an electrician's workplace can include the location of the necessary tools. Before installing, dismantling or repairing equipment, you should place it correctly so that you do not have to be distracted from your work by searching for a screwdriver or multimeter.

Important! An electrician's work tools should be checked daily for cracks or other damage to insulated parts. This simple inspection will help save life and health.

An important and sometimes decisive role in ensuring the safety of the workplace is played by warning signs, which will protect the installer if the power outage was carried out far from him. They are most often made in the shape of a rectangle or square with a red border and a warning, or with white lettering on a red background. This is done to make the notification more noticeable.

Other measures taken for labor protection

Before allowing an employee to enter the workplace, the necessary instructions are given. This is not surprising, because working with high voltage is dangerous. Even experienced employees often make mistakes. The main one can be called the initial briefing of the electrician at the workplace. Without it (as well as without an induction), the hired employee will not be allowed to perform repairs and maintenance.

Persons responsible for ensuring labor safety of electricians

At any enterprise, regardless of its profile, persons responsible for the safety of electricians in the workplace are appointed. The first person to bear responsibility when an employee is injured is his immediate supervisor who conducted the training. Further down the chain:

• safety engineer;
• Chief Power Engineer;
• head of the enterprise.

Most often, such situations occur due to the fault of the electrician himself, who ignored the safety rules.

Electrician's workplace for repair and maintenance of electrical equipment

This position requires an almost constant presence at a specific workplace. What is important here is not only the convenient placement of all tools, but also well-designed lighting, allowing the worker to see the smallest details of the equipment being repaired. If there is insufficient lighting, he will have to strain his eyes, which will lead to rapid fatigue.

How to equip an electrician's workbench

The electrician's workplace for equipment repair must be equipped with:

• a transformer device that allows you to change the supplied voltage;
• ability to turn on/off additional spot lighting;
• 12, 24 or 36 V socket;
• a set of tools necessary for diagnostics and repairs.

Electrical shop auxiliary equipment

As auxiliary devices we can name devices and mechanisms that are useful to an electrician for the repair and maintenance of electrical equipment. Usually a sharpening, winding machine and a vice are sufficient. To store various small parts, pull-out cabinets or metal boxes are used.

Workplace of a trainee electrician

The organization of a trainee electrician's workplace is practically no different from the workbench of an experienced craftsman. Experts advise installing it so that the mentor has the opportunity to monitor the student’s work. This is especially important in the first days. Most often, during this time of responsible work, the newcomer is not trusted, but the master can understand how responsible the trainee is in his duties.

For those who want to choose a similar difficult, but very an interesting profession, but is still thinking, we recommend the following video.

To make it easier for the student, several practical advice:

1. Strict adherence to the instructions of the mentor is the key to successful training.
2. Should not be left workplace without informing the teacher.
3. The placement of the tool on the workbench must comply with the instructions of the master - he has considerable experience behind him.
4. Items not related to the work being performed should be removed from the workbench.

It is important that the trainee understands from the first day that not only how much easier it will be to work later depends on strict adherence to instructions, attentiveness and accuracy. The smallest banal violation of occupational safety and health regulations can lead to electric shock or fire.

Rules for preparing a workplace at a distribution substation

Here the requirements for the electrician's workplace are more stringent. The main task can be called preliminary actions that need to be completed.

Due to the high voltage on transformer substation The electrician is required to prepare protective equipment ( latex gloves, shoes, workwear), necessary tools. Upon arrival at the site, you must obtain permission from the duty officer, which is noted in the permit. After this, preparation is carried out, in which both the electrician and the duty officer participate.

The first step is to de-energize the line by turning off the switch. If this action impossible, the fuses are pulled out. This work requires maximum attention and mandatory application protective equipment- rubber gloves, safety shoes, pliers). Having de-energized the line, it is necessary to ensure the safety of the electrician from accidental switching on. This is done by grounding the busbars. Only after this can we consider that the organization of the electrician’s workplace has been completed completely, and he can begin work.

General rules for safety and maintenance of the workplace

Summarizing the information presented, we can note the basic rules for organizing the safety and maintenance of an electrician’s workplace.

1. Timely completion of necessary instructions.
2. Lack of clutter, ensuring a free approach to the input machine for the possibility of emergency shutdown in the event of an emergency.
3. The tools are neatly placed within easy reach so that taking what you need is not difficult.
4. If necessary, use protective equipment.
5. No exposed wires that could be live.
6. Strict adherence to all instructions and instructions of the master. Attentiveness, composure, accuracy.
7. Mandatory stress relief before starting electrical installation work.
8. Use of special warning and prohibition signs.

Only if all the rules are followed can a worker become a professional electrician capable of performing complex tasks. And the main thing is to remember that this profession can be compared to a sapper - his mistake in demining can also be the last in his life. However, the profession of an electrician is quite interesting, especially today, when new equipment is constantly appearing. This means there is always a possibility professional growth and self-education.

Finally

To summarize, we can say that the safe organization and maintenance of an electrician’s workplace is not the least important in the task of labor protection. You shouldn't be skeptical about it - trash under your feet can be very expensive. And you will have to pay for it not with money, but own health, and sometimes life.

In electrical installations with voltage up to 1 kV, work on switchgear busbars, distribution boards, assemblies, as well as at the connections of the listed devices, through which voltage can be supplied to the busbars, must be carried out in order. At dead-end connections, work may be carried out by order.

When working in electrical installations in which the voltage has been removed from all live parts, including the terminals of overhead lines and cable lines, provided that the entrance to adjacent electrical installations is locked (assemblies and panels with voltages up to 1 kV can remain energized), it is allowed to issue one work order for simultaneous operation on all connections.

The switchgear electrical equipment being repaired must be disconnected with a visible circuit break on all sides from where voltage can be supplied to it.

In electrical installations with voltages up to 1 kV, voltage relief is carried out by turning off devices with manual drive, and if there are fuses in the circuit, remove them. If there are no fuses in the circuit, erroneous switching on of the device is prevented by locking the handles, locking the cabinet doors, and installing insulating pads between the contacts of the device.

When working on the equipment of a trolley or in a compartment of a switchgear cabinet, the trolley with the equipment must be rolled out into the repair position; Lock the curtain of the compartment in which live parts remain energized and hang a safety poster “Stop! Voltage"; Display a “Work here” sign on the cart or in the compartment where you will be working.

When working outside the switchgear on equipment connected to them or on outgoing overhead lines and cable lines, the trolley with the switch must be rolled out of the cabinet into the repair position, the curtain or doors must be locked and signs “Do not turn on!” must be posted on them. People are working" or "Don't turn it on! Work on the line."

In this case it is allowed:

• - if there is a blockage between the grounding knives and the trolley with the switch, install the trolley in the control position after turning on these knives;
• - in the absence of such a lock or grounding blades in switchgear cabinets, install the trolley in an intermediate position between the control and repair positions, provided that it is locked with a lock. The trolley can be installed in an intermediate position regardless of the presence of grounding at the connection.

Installing a trolley with a switch in the control position for testing and working in control and protection circuits is permitted in cases where work outside the switchgear on outgoing overhead lines and cable lines or on the equipment connected to them, including mechanisms connected to electric motors, is not carried out or grounding is carried out in switchgear cabinet.

Repair work in electrical distribution installations up to 1 kV, taking into account their small dimensions, is carried out under the condition that live parts under voltage, which can be accidentally touched, are fenced off near the workplace. You must work in dielectric galoshes or on an insulating stand or mat; use the tool with insulating handles. It is prohibited to work in a bent position if, when straightened, the distance to live, non-disconnected parts is less than 0.6 m. It is unacceptable for unprotected live parts to be located behind the worker or on both sides.

Scaffolds and ladders must be in good working order. Application metal stairs forbidden. Work using ladders is carried out by two people, one worker should be at the bottom.

During the period of electrical repair work, it is prohibited:

• - work with power tools that do not have double insulation and are powered by a voltage of more than 42 V;
• - disassemble power tools and make any repairs to power tools.

The repair tool should be stored in a specially designated place. Electric soldering irons must be installed only on special metal stands.

To remove excess solder from the rod of an electric soldering iron, you must use a cotton cloth or an asbestos pad. Shaking the electric soldering iron is strictly prohibited. Cleaning the rod of an electric soldering iron and replacing the heating element can only be done when the electric soldering iron is disconnected from the power supply and in a cold state.

When desoldering or pulling wires from a connector, wear safety glasses to avoid splashing molten solder into your eyes or face. Particular care must be taken when tinning rigid wires and cable strands, which can spring back and splash molten solder. It is not allowed to immerse heat-resistant insulation and other materials that emit toxic volatile substances when heated, as well as wet materials, into a crucible with molten solder, as this may cause the release of molten solder. Check the strength of the crucible fastening to avoid its possible overturning, the serviceability and reliability of the crucible grounding.

Overhauls of equipment (RU) include external and internal inspections of all elements of the circuit; checking the state of insulation of devices and wiring; revision of all devices included in the scheme in accordance with the instructions for individual devices; checking relay settings; checking the operation of the entire circuit without turning on the power circuits; checking the operation of the entire installation in operation.

Routine repairs and inspections of devices that require more frequent checks than the entire installation as a whole are carried out according to a reduced program.

Unscheduled repairs and inspections are carried out after the accident has been eliminated.

Planned repairs are carried out in the following periods:

Boards, panels, cabinets and control assemblies.....................................1 time per year

Equipment for lifting and transport mechanisms............................2 times a year

Control relays, contactors, starters................................................. Monthly

Controllers, command devices...................Inspection - upon acceptance of a shift,

revision - during a planned shutdown of the mechanism (but at least once every 4-6 months) Automatic switches................................... ............................Monthly

Before starting repair work, the foreman must explain to the workers the features of a particular reactor plant and the situation on it. In particular, you should indicate:

• - access routes to each workplace, the presence of dangerous zones;
• - procedure for connecting electrical devices and tools;
• - places and procedure for installing lifting equipment in the repair area;
• - presence of existing electrical installations nearby and appropriate safety measures.

In turn, before starting work, electricians are obliged to:

• - check the serviceability of your tools, equipment, devices and arrange them in an order that is convenient and safe for use;
• - tidy up overalls and hats;
• - inspect and prepare your workplace, remove unnecessary items.

Chopping-type devices are installed during repairs so that they cannot close the circuit spontaneously under the influence of own strength gravity. Switching device drives must clearly indicate the on and off positions. The equipment of switchgears, switchboards, and assemblies must be accessible for inspection, provided that the control panel is connected to the network. After equipment repairs, panels must be clearly labeled to indicate which unit they belong to. Such inscriptions must be on the front and reverse sides panels. All keys, buttons and control handles must have inscriptions indicating the operation for which they are intended (“Enable”, “Disable”, “Add”, etc.).

When repairing circuit breakers (switches), thoroughly clean the contact surfaces of the knives and sponges from dirt, soot and particles of melted metal. In case of severe melting, replace the jaws or knives with new ones, tighten all fasteners and hinge joints, check the condition of the springs and spring brackets; weakened springs are replaced with new ones. Make sure that the knives enter the jaws without impacts or distortions, but with some effort.

The contact surface of the sponge should fit snugly against the corresponding surface of the knife. A probe with a thickness of 0.05 mm should enter the space between the sponge and the knife to a depth of no more than 6 mm.

The depth of entry of the knives into the jaws is adjusted so that for a switch with a lever drive, the knives, when in the fully engaged position, do not enter 3 mm to the contact area of ​​the jaws. At the same time, the entire contact part of the knife should fit into the jaws. The non-simultaneous exit of the knives from the contact jaws should not exceed 3 mm.

Push-button stations, cam control devices, universal switches and limit switches do not require special adjustment. They only check the free movement of moving parts, touching and pressing contacts in the on position, and the compliance of universal switches and command devices with contact switching circuits. The rollers of the control devices must rotate freely.

For contactors and magnetic starters, by turning them on by hand with the voltage removed, the ease of movement of the moving system is checked. If the shaft jams in the bearings, 3-4 drops of machine oil are introduced into the bearings through special holes. If, after lubrication, the shaft rotates tightly, then it is necessary to eliminate the distortion in the bearings, for which the bolts securing the bearings are loosened and a position corresponding to free movement is found, then the fastening bolts are tightened again.

It is necessary to check the tight fit of the armature and yoke of the magnetic system, thoroughly cleaning their end parts from dirt and rust, which avoids vibration and the associated increased wear of the device. The tightness of the anchor is checked with a probe 0.05 mm thick. The short-circuited damper turn in the core slot must be tightly clamped in its groove and must not have a break.

Mechanical interlocking should not prevent the interlocked devices from being fully switched on. When one device is turned on, you need to make sure that it is impossible to turn on the interlocked device.

Repair of switchgears and equipment with voltage over 1 kV. In a 6...10 kV switchgear with a single busbar system and any number of sections, when the entire section goes out for repairs, one work order is issued to work on the busbars and on all or part of the connections of this section. Admission to all workplaces of the section is carried out simultaneously; the team is allowed to disperse among different work places within this section.

It is prohibited to prepare for switching on or testing under voltage any connection of a section until work on the work is completed.

One work order for the simultaneous or alternate performance of work at different workplaces of one or several connections without registration of transfer from one workplace to another with the dispersal of the team among different workplaces may be issued in the following cases:

• - when laying and relaying power and control cables, testing equipment, checking protection devices, interlocks, automation, etc.;
• - repair of switching devices when their drives are located in another room;
• - repair of a separate cable in a tunnel, collector, well, trench, pit;
• - repair of cables (no more than two), carried out in two pits or a closed-circuit switchgear and a nearby pit, when the location of the workplaces allows the work supervisor (supervisor) to supervise the team.

When carrying out work, all workplaces must be prepared before admission. If the team is dispersed among different work places, the following is allowed to remain: one or more team members with electrical safety group III, separately from the work performer; team members who will have to be separate from the work contractor; the latter must bring them to their workplaces and instruct them regarding work safety.

For safety reasons, before being allowed to operate switching devices with remote control, the following must be in place:

• - the drive power circuits, operating current circuits and heating circuits are disconnected;
• - the valves on the air supply pipeline to the pneumatic drives are closed and locked; the air present in them is released into the atmosphere, while the starting plugs (valves) are left in the open position;
• - the closing weight or closing springs are brought into non-working position;
• - posters “Do not turn on! People are working" on remote control keys and "Do not open! People are working” - on closed valves.

For test switching on and off of the switching device during its setup and adjustment, it is allowed, if the work order has not been handed in, to temporarily supply voltage to the operating current circuit and the power circuit of the drive, to the signaling and heating circuit, as well as to supply air to the drive and to the switch.

Installing removed fuses, turning on disconnected circuits and opening valves when supplying air, as well as removing “Do not turn on!” posters during testing. People are working" and "Don't open! People work” is carried out by operational personnel or, with their permission, by the work performer. The person performing the adjustment or adjustment, or at his request, the operating personnel, is allowed to remotely turn on or turn off the switching device for testing.

After testing, if it is necessary to continue working on the switching device, a person from the operating personnel or with his permission from the work manufacturer must carry out the technical measures required for permission to work.

Lifting onto an air circuit breaker under operating pressure is only permitted during testing and commissioning work(adjusting dampers, taking vibrograms, connecting or disconnecting conductors from measuring instruments, identifying air leaks, etc.).

Climbing onto a disconnected air switch with an air-filled separator, when the separator is under operating pressure, is prohibited in all cases.

The moisture resistance (tightness) of air switches is checked under reduced pressure in accordance with factory instructions.

Before climbing onto the air circuit breaker for testing and adjustment, you must:

• - disconnect the operating current circuits;
• - block the local control button and starting valves (for example, disconnect the air duct pipes, lock the cabinets, etc.) or place an instructed team member near the switch, who would allow only the responsible person to operate the switch (after turning on the operating current), as directed by the work manager.

While people are on the air circuit breaker under pressure, stop all work in the control and distribution cabinets.

At the time of switching off and switching on air switches during testing, adjustment and testing, the presence of people near the switches is not allowed.

The tester and commissioner (or a person authorized by him from the team) can give a command to perform operations with the circuit breaker after the team members have moved away from the circuit breaker to a safe distance or to shelter.

Before permission to work involving people staying inside air collectors, you must:

• - close the valves on all air ducts through which air can be supplied, lock them, and hang posters on the valves “Do not open! People are working";
• - release the air under pressure in the air collector, leaving the plug in its upper part and the drain valve open;
• - disconnect the air supply duct from the air collector and install plugs on it.

A zero reading of pressure gauges on switch tanks and air collectors cannot serve as a reliable indication of the absence of compressed air. When removing manhole covers, immediately before unscrewing the bolts and nuts, it is necessary to ensure that there is actually no compressed air by opening the drain plugs (valves) or valves.

Drain plugs (valves) or valves may be closed only after screwing in the bolts and nuts securing the manhole cover.

In switchgear with equipment on roll-out trolleys, it is prohibited to enter compartments that are not separated by solid metal partitions from the buses or equipment directly connected to them without removing the voltage from the busbars and grounding them. To work on outgoing cables, electric motors and other equipment directly connected to these cables, carts with switches are completely rolled out, cabinet doors or automatic curtains are locked and a “Do not turn on!” sign is posted on them. People are working."

The cables in the switchgear compartments are grounded. In cases where grounding is applied at the work site, it is not necessary to apply it in the switchgear compartments.

In case of work on cable funnels installed in switchgear compartments, the trolleys with switches are completely rolled out, and a poster “Do not turn on!” is hung on the doors or back wall of the compartment. People are working,” the automatic curtains are locked, and a sign “Stop!” is hung on the top curtain. Voltage". To access the compartment, remove the vertical partition inside the cabinet or the back wall; on cables through which voltage can be supplied, check for its absence and apply grounding; a “Work here” poster is hung in the compartment. When working on switchgear equipment located on trolleys, they are completely rolled out and a “Work here” poster is placed on the equipment. During work in the compartments, a “Work Here” poster will be displayed inside the compartment.

After the cart is rolled out, the cabinet doors are locked and a sign “Do not turn on!” is hung on them. People are working." If there is no door, the automatic curtains are locked and a sign “Stop!” is hung on them. Voltage". When working on devices, relays, secondary circuits, etc. without rolling out carts with equipment, hang a sign “Do not turn on! People are working,” and at the work site there is a poster “Work here.”

The trolley with the switch can be installed in the test position in the following cases:

• - for testing the switch and adjusting the drive, checking the relay protection of the connection;
• - when preparing and assembling the diagram after completion of work and delivery of the work order;
• - when working on the mechanical part of an electric motor or on the mechanism driven by it.

In this case, a poster “Do not turn on!” is hung on the locked cabinet doors. People are working."

Work in the switchgear room is carried out one by one and only on a trolley with equipment rolled out of the cabinet.

Rolling out a trolley with a switch or other equipment completely from the cabinet or into a test position, as well as rolling it in and installing it in place is carried out by an operating personnel with qualification group IV, individually or under his supervision, with a preliminary check of the disconnection of the grounding knives.

The type of operational maintenance of an electrical installation, the number of employees from among the operational personnel per shift is determined by the management of the structural unit and is fixed by the corresponding order. Work in electrical installations and electrical equipment is carried out according to the work permit (hereinafter referred to as the work order), according to the order, according to the list of works performed in the order of routine operation.

3.2.1.1. In the order of current operation, only those works are performed that are approved in the list of works in the order of current operation.

3.2.1.2. By order the following is carried out:

Stress relief work:

Power supply connection for electrical installations with voltages up to 1000 V;

Replacement of elements and parts, measuring instruments on the control panel, relay panels, system racks automatic regulation tension;

Cleaning of devices, installation of switches, switches, magnetic starters, checking the reliability of contactors on switches, clamps, tips of AC and AC input distribution devices direct current all types;

Work without stress relief:

Cleaning, external inspection of input power and relay panels, remote power racks and boards, automatic voltage control systems, AC and DC switchboards and panels and other distribution devices;

Replacement of 15 - 100 A fuses in lightning protection devices (GPA) on input panels.

3.2.1.3. The right to issue orders and instructions regarding distance is granted to administrative and technical personnel who have an electrical safety group of at least IV.

3.2.1.4. For each workplace where work is carried out on a regular basis, a technological map for preparing the workplace is developed, approved by the person responsible for electrical equipment.

3.2.1.5. Technological maps jobs associated with provision by the energy supply organization are agreed upon with the energy supply organization.

3.2.1.6. The operational and repair personnel of the distance, who individually service electrical installations (senior electrician, electrician, section manager, etc.), must have at least III electrical safety group.

At the workplace of operational personnel there must be a list of electrical personnel who are granted the right to individually inspect electrical installations, approved by the person responsible for electrical equipment.

3.2.1.7. Before starting work on the panel guaranteed power supply the observer must agree with the energy dispatcher on the location, content and categories of work.

3.2.1.8. An internal check of the guaranteed power supply panel should be carried out with the voltage removed on the main and backup feeders. Voltage relief is carried out by employees of the power supply distance.

3.2.1.9. The housings of switchboards, cabinets, and assemblies must be grounded. The need and possibility of grounding the connections of these boards, assemblies and equipment connected to them is determined by the issuing order or order.

Operations for installing and removing groundings are allowed to be performed by one employee from among the operating personnel.

3.2.1.10. Before performing work in the ASU, you must ensure that the protective grounding ASU housings. To do this, first of all, it is necessary visual inspection make sure the integrity of the conductor. It is necessary to check the absence of voltage using a voltage indicator. The serviceability of the voltage indicator before its use must be established using special devices intended for this purpose or by approaching live parts located nearby and known to be under the appropriate voltage. If the tested voltage indicator has been dropped or been subjected to shocks (shocks), then it is prohibited to use it without re-checking.

3.2.1.11. Monitoring the integrity of the grounding must be done while wearing dielectric gloves by lightly shaking the grounding conductors connected to the ASU body.

3.2.1.12. Before opening the outer door of the switchboard, make sure that there is a dielectric mat on the floor.

3.2.1.13. The voltage level is monitored using indicators built into the switchboard panel. The measurement results must be recorded in the inspection log of power supply devices.

3.2.1.14. Control switching of power feeders must be carried out wearing dielectric gloves using automatic power switches. Each time one of the machines is turned off, the power switching circuit to another feeder should be automatically activated.

3.2.1.15. Cleaning internal elements from dust and dirt is done with a dry brush, and the external surfaces of the cabinets with a dry rag or rag, without touching the metal parts with your hands.

3.2.1.16. Cleaning the switch contacts from carbon deposits and dirt should be carried out wearing dielectric gloves using an insulating tool, with the voltage removed.

3.2.1.17. When performing work without relieving voltage on live parts using insulating protective equipment, it is necessary to:

Hold the insulating parts of the protective equipment by the handles up to the restrictive ring;

Arrange the insulating parts of the protective equipment so that there is no danger of overlap along the insulation surface between the current-carrying parts of two phases or a ground fault;

Use only dry and clean protective equipment with intact varnish.

When a violation is detected varnish coating or other malfunctions of the insulating parts of protective equipment, their use must be stopped immediately.

3.2.1.18. Replacement of fuses in ASU under voltage must be done using insulating pliers (or special devices), wearing dielectric gloves and using face and eye protection.

Replacement should be done slowly and carefully. First, make a test movement with the drive lever in order to make sure that the rods are in good condition and that there are no swings or damage to the insulators.

3.2.1.19. It is not allowed to use uncalibrated fuses and fuses.

3.2.1.20. In electrical installations, working in a cramped position is not allowed. When working in close proximity to unprotected live parts, you must not position them so that these parts are at the back or on both sides.

3.2.1.21. When a thunderstorm approaches, all work in the ASU must be stopped.

3.2.1.22. Replacement work circuit breakers located on interior panel New generation ASUs (such as SUEP-2, UEPS-2 and their analogues) must be produced using hand tools with insulating handles (screwdrivers, pliers, etc.) without dielectric gloves. Avoid touching the bare ends of the wires leading to the switches, which may be energized at 220 V.

3.2.1.23. Replacement of lighting lamps in the ASU and battery rooms is permitted to be carried out solely by operational personnel.

3.2.1.24. It is not allowed to change lamps on ladders alone.

3.2.1.25. The premises in which the ASUs are located must be equipped primary means fire extinguishing in accordance with approved standards.

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