The main tasks of servicing distribution devices (RU) are: ensuring the specified modes of operation and reliability of electrical equipment, compliance with the established procedure for performing operational switching, control over the timely conduct of planned and preventive work.

The reliability of work is made to characterize the specific damage to 100 connections. Currently, for RU 10 kV, this indicator is at the level of 0.4. The most unreliable elements RW are switches with a drive (from 40 to 60% of all damage) and disconnectors (from 20 to 42%).

The main causes of damage: breakage and overlapping of insulators, overheating contact connections, driven drives, damage due to incorrect actions of the service personnel.

Inspection of the RU without shutdown should be made:

at objects with constant. Human staff - at least 1 time in three days,

at facilities without permanent duty personnel - at least 1 time per month,

on transformer points - at least 1 time in 6 months,

RU voltage up to 1000 V - at least 1 time in 3 months (on KTP - at least 1 time in 2 months),

after turning off the short circuit.

When conducting inspections, check:

control of lighting and grounding network,

availability of means of protection

level and temperature of oil in oil-filled devices, no leaving oil,

the condition of insulators (dustiness, the presence of cracks, discharges),

contact condition, integrity FLB Counters and relays,

reference and correct position of switches position pointers,

operation of the alarm system,

wellness and ventilation,

the condition of the room (the serviceability of doors and windows, the absence of leaks in the roof, the presence and health of locks).

Extraordinary inspections of open distribution devices are carried out with adverse weather conditions - strong fog, ice, enhanced pollution of insulators. The inspection results are recorded in a special magazine to take measures to eliminate identified defects.

In addition to inspections, equipmentdeleting devices are subjected to preventive checks and tests performed according to the PPR. The amount of measures carried out is regulated and includes a number of common operations and individual work specifics specific for this type.

General include: Measurement of insulation resistance, checking the heating of bolted contact connections, measuring the resistance of the contacts to DC. The specifics of the time and movement of moving parts, the characteristics of the switches, the operation of the free-length mechanism, etc.

Contact connections are one of the most vulnerable places in distribution devices. The condition of contact compounds is determined by the external inspection, and when conducting preventive tests - with the help of special measurements. With an external inspection, pay attention to the color of their surface, evaporation of moisture during rain and snow, the presence of glow and sparking of contacts. Preventive tests include checking the heating of bolted contact connections with thermal indices.

Basically use a special thermal film, which has a red color at normal temperature, cherry - at 50 - 60 ° C, dark cherry - at 80 ° C, black - at 100 ° C. At 110 ° C for 1 hour it is destroyed and takes a light yellow color.

Thermal film in the form of circles with a diameter of 10 - 15 mm or strips is pasted in controlled location. At the same time, it should be clearly visible to operational personnel.

RU 10 kV tires should not be heated above 70 ° C at an ambient temperature of 25 ° C. Recently, electrothermometers on the basis of thermistributions, heatmad, thermal imagers and pyrometers are used to control the temperature of the contact compounds (act on the principle of use of infrared radiation).

Measuring the transitional resistance of contact connections is carried out for the tires for the current of more than 1000 A. The work is performed on a disconnected and grounded equipment using a microgrammeter. At the same time, the resistance of the tire portion at the site of the contact compound should not exceed the resistance of the same area (in length and section) of the entire tire of more than 1.2 times.

If the contact compound is in unsatisfactory condition, it is repaired, for which they are disassembled, cleaned from oxides and contamination, covered with special lubrication from corrosion. The reverse tighten is performed by a key with adjustable torque in order to avoid deformation.

The insulation resistance measurement is carried out for the suspended and supporting insulators with a 2,500 V, and for secondary circuits and equipment, RU up to 1000 V is a megoometer for 1000 V. Isolation is considered normal if the resistance of each insulator is not less than 300 mΩ, and the insulation resistance of secondary chains and equipment RU up to 1000 V is less than 1 mΩ.

In addition to measuring insulation resistance, supporting one-element insulators are exposed to an increased voltage of industrial frequency for 1 min. For low-voltage networks, the test voltage of 1 kV, in 10 square meters - 42 kV networks. The control of multi-element insulators is carried out at a positive ambient temperature with a measuring rod or a rod with a permanent spark gap. For the rejection of insulators, special stress distribution tables are used in garlands. The insulator is worn if it accounts for a voltage less permissible.

During operation on the surface of the insulators, a contamination layer is postponed, which is not dangerous in dry weather, but with a drizzling rain, fog, the wet snow becomes conductive, which can lead to the overlapping of insulators. To eliminate emergency situations, insulators periodically purify, rubbing manually, with a vacuum cleaner and hollow rods from an insulating material with a special tip in the form of curly brushes.

When cleaning the insulators, water jet is used on open distribution devices. To increase the reliability of the insulators, their surface is treated with hydrophobic pastes with water repellent properties.

The main damages of disconnectors are the burning and welding of the contact system, fault of insulators, drive, etc. When detecting traces of burning, the contacts are cleaned or deleted by replacing new, tighten the bolts and nuts on the drive and in other places.

When regulating three-pole disconnectors check the simultaneity of the knives. In a properly adjusted disconnector, the knife should not reach the contact site by 3-5 mm. The pulling force of the knife from a fixed contact should be 200 H for the disconnector to the nominal currents of 400 ... 600 A and 400 H - on currents 1000 - 2000 A. The rubbing parts of the disconnector are coated with non-freezing lubricant, and the surface of the contacts is a neutral vaseline with admixture of graphite.

In case of inspections of oil switches, insulators, traction, the integrity of the safety valves membrane, the oil level, the color of the thermal film are checked. The oil level should be within the allowable values \u200b\u200bon the level indicator scale. The quality of contacts is considered satisfactory if the transient resistance corresponds to the manufacturer's factory.

In case of inspections of the oil switching switches draw attention to the condition of the tips of the contact rods, the intake of flexible copper compensators, porcelain thrust. When the breakdown of one or more pull, the switch is immediately displayed.

The abnormal heating temperature of the exhausting contacts causes a darkening of oil, lifting its level and characteristic smell. If the tank temperature of the switch exceeds 70 ° C, it is also displayed.

The most damaged elements of oil switches remain their drives. Drive failures Be due to malfunctions of control circuits, increasing the locking mechanism, faults in movable parts and breakdown of insulation of coils.

The current repair of switchgear is carried out to ensure the performance of the equipment before the next scheduled repair and provides for the restoration or replacement of individual nodes and parts. Overhaul is performed to restore full performance. It is carried out with the replacement of any parts, including the basic.

The current repair of distribution devices with voltage above 1000 V is performed as needed (within the time set by the chief engineer of the energy enterprise). Overhaul of oil switches is carried out 1 time in 6 - 8 years, load switches and disconnectors - 1 time in 4 - 8 years, separators and short-circuiters - 1 time in 2 - 3 years.

The current repair of distribution devices by voltage up to 1000 V is carried out at least 1 time per year on open TP and after 18 months on closed TP. At the same time, the state of the end sealing is monitored, cleaning from dust and dirt, as well as the replacement of insulators, is repaired tires, the touch of contact connections and other mechanical nodes, the light and sound signaling circuits are repaired, the measurement and testing standards are carried out.

The overhaul of switchgear voltage up to 1000 V is carried out at least 1 time in 3 years.

Repair daily engage in thousands of people around the world. When it is fulfilled, everyone begins to think about the subtleties that accompany the repair: in what color scheme to choose the wallpaper, how to choose the curtains in the color of the wallpaper, to properly place the furniture to obtain a single room style. But the most important thing is rarely wondering, and this main thing is to replace wiring in the apartment. After all, if something happens to the old wiring, then the apartment will lose all its attractiveness and will become absolutely not suitable for life.

How to replace the wiring in the apartment knows any electrician, but this is under power to any ordinary citizen, but when performing this type of work, it should choose high-quality materials to get a secure electrical network indoor.

The first action that needs to be performed plant future wiring. At this stage, it is necessary to determine which locations will be laid wires. Also at this stage you can make any adjustments to the existing network, which will allow the lamps as comfortable as possible in accordance with the needs of the owners.

12.12.2019

Nercho-separable instruments knitted sub-sectors and their maintenance

To determine the extensibility of hosiery products, the device is used, the diagram of which is shown in Fig. one.

The design of the device is based on the principle with automatic rocker equilibration by the elastic forces of the test products acting at a constant speed.

Weight rocker is an equal deploying round steel rod 6 having an axis of rotation 7. It is attached to its right end using a paw bayonet lock or a sliding track shape 9 for which the product dresses. On the left shoulder, the cargo suspension 4 is highlighted, and its end ends with an arrow 5 showing the equilibrium state of the rocker. Before the testing of the product, the rocker is leading to the equilibrium of the movable gay 8.

Fig. 1. Diagram of the device for measuring the extensibility of humene-socks: 1-receiver, 2 - left ruler, 3 - engine, 4 - cargo suspension; 5, 10 - arrows, 6 - rod, 7 - axis of rotation, 8 - weight, 9 - Form of a trace, 11-tensile lever,

12-carriage, 13 - chassis screw, 14 - right line; 15, 16 - Screw gears, 17 - worm gearbox, 18 - connecting coupling, 19 - electric motor

To move the carriage 12 with the tensile lever 11 serves the chassis screw 13, at the bottom end of which the screw gear 15 is fixed; Through it, the rotational movement is transmitted to running screw. The change in the direction of rotation of the screw depends on the change in rotation 19, which with the help of the coupling 18 is associated with the worm gearbox 17. A screw gear 16 is planted on the shaft of the gearbox, directly reporting the movement of the gear 15.

11.12.2019

In pneumatic actuating mechanisms, the permutational effort is created due to the impact of compressed air on the membrane, or the piston. Accordingly, the mechanisms of membrane, piston and bellows are distinguished. They are designed to install and move the gate of the regulating organ in accordance with the pneumatic command signal. The full working stroke of the output element of the mechanisms is carried out when the command signal changes from 0.02 MPa (0.2 kg / cm 2) to 0.1 MPa (1 kg / cm 2). The limit pressure of compressed air in the working cavity is 0.25 MPa (2.5 kg / cm 2).

At the membrane rigid mechanisms, the rod makes a reciprocating movement. Depending on the direction of the movement of the output element, they are divided into direct operational mechanisms (with the increase in the pressure of the membrane) and reverse action.

Fig. 1. Construction of a membrane actuator direct action: 1, 3 - Covers, 2-membrane, 4 - reference disk, 5 - Bracket, 6 - Spring, 7 - rod, 8 - support ring, 9 - Adjusting nut, 10 - connecting nut

The main structural elements of the membrane actuator are a membrane pneumatic chamber with a bracket and a movable part.

The membrane pneumatic camera of a direct action mechanism (Fig. 1) consists of covers 3 and 1 and membrane 2. Cover 3 and membrane 2 form a hermetic working cavity, the cover 1 is attached to the bracket 5. To the moving part include the reference disk 4 to which the membrane is attached 2, rod 7 with connecting nut 10 and spring 6. The spring is resting in one end to the reference disk 4, and the other through the support ring 8 into the adjusting nut 9, which serves to change the initial tension of the spring and the direction of the rod movement.

08.12.2019

To date, there are several types of lamps for. Each of them has its pros and cons. Consider the types of lamps that are most commonly used for lighting in a residential building or apartment.

First type of lamps - incandescent lamp. This is the cheapest view of the lamps. The advantages of such lamps include its cost, ease of device. Light from such lamps is the best for the eyes. By cons of such lamps include low life and a large amount of electricity consumed.

Next type of lamps - energy-saving lamps. Such lamps can be found absolutely for any types of bases. Present an elongated tube in which special gas is located. It is gas that creates a visible glow. In modern energy-saving lamps, the tube can have the most diverse shape. Pluses of such lamps: Low power consumption compared to incandescent lamps, daylight, large selection of basements. By cons of such lamps include the complexity of the design and flicker. Flicker usually unnoticed, but the eyes will be tired of light.

28.11.2019

Cable assembly - The type of mounting node. The cable assembly is several local, ended on both sides in the electrical workshop and linked to the bundle. Installation of the cable route, is carried out by placing the cable assembly in the fixing device of the cable route (Fig. 1).

Ship cable route - electric line mounted on a vessel from cables (cable beams), cable route devices, sealing devices, etc. (Fig. 2).

On the vessel, the cable track is placed in hard-to-reach places (on sides, subwoulder and bulkheads); They have up to six turns in three planes (Fig. 3). On large courts, the greatest length of the cables reaches 300 m, and the maximum cross-sectional area of \u200b\u200bthe cable route is 780 cm 2. On separate ships with a total cable length over 400 km, cable corridors provide for the placement of the cable route.

Cable runs and cables passing on them are divided into local and trunk depending on the absence (presence) of sealing devices.

The main cable tracks are divided into tracks with elder and passing boxes, depending on the type of cable box. It makes sense to choose tools for technological equipment and technology of mounting the cable route.

21.11.2019

In the field of development and production of instruments of kipia, the American company Fluke Corporation occupies one of the leading positions in the world. It was founded in 1948 and from that time constantly develops, improves technology in the field of diagnosis, testing, analysis.

Innovation from the American Developer

Professional measuring equipment from a multinational corporation is used when servicing heating, air conditioning and ventilation systems, refrigeration installations, air quality checks, electrical parameter calibrations. Fluke's corporate store offers to purchase certified equipment from the American developer. Full lineup includes:

• thermal imagers, insulation resistance testers;
• digital multimeters;
• electric energy quality analyzers;
• rangefinders, vibrors, oscilloscopes;
• temperature calibrators, pressure and multifunctional devices;
• visual pyrometers and thermometers.

07.11.2019

Use a level gauge to determine the level of different types of liquids in open and closed storage facilities, vessels. With it, they measure the level of the substance or distance to it.
To measure the level of fluid, sensors are used, which differ in type: a radar level gauge, microwave (or waveguide), radiation, electric (or capacitive), mechanical, hydrostatic, acoustic.

Principles and features of working radar levels

Standard devices do not determine the level of chemically aggressive liquids. Only a radar level gauge is able to measure it, as it does not come into contact with fluid when working. In addition, radar levels are more accurate compared, for example, with ultrasound or with capacitive.

For mounting any type of rch - and power, and used for lighting, similar components are used. These are: automation, terminal tires (one for grounding - re, one for "clean" neutral and one for each diffrela). Also, do not do without NSHVI (tips of pinching sleeve isolated) and cable screeds (plastic homutics) in the case of using jumpers from the stranded wire.

Acquire everything you need best in specialized online stores that are willing to provide certificates of compliance with their goods to current standards and guarantee. Moreover, automation, terminal tires should be purchased exactly in the required quantity, but the tips and cable ties are recommended to be ordered with some reserve, because the installation process does not exclude errors that will require alterations.

What kind of company is preferable? Today, the production of high-quality automation is concentrated in Europe. One of the most popular premium products are LEGRAND, Siemens, ABB brand devices. Significantly more affordable, moreover, the products of the Russian trademark of IEK (interielectrocomplekt) are considered quite a bit inferior.

Mounting process

1. First, it is recommended to install all automatic / protection devices, terminals on DIN rail, achieving the optimal location of each element. By installing terminal blocks in the ceramic block, caution should be taken because of the increased fragility of the latter.
2. Then the flexible jumpers are prepared and connected. In household electrical panels with automation by 40-50 and as the latter, the segments of the insulated wire PV-3 (6 mm2) are used, and the ends of which are injected with NSHA. When preparing the jumpers, it is necessary to take into account the color of the insulation - for phase compounds, brown or black are usually used for neutral lines - blue or white. In order for the wires reliably held inside Rush, easily viewed, it is recommended to fix them with cable screeds.
3. Next, you can proceed to connecting the introductory cable. It should be previously verified in the absence of voltage on its wires. If this is available, de-energize the cable, having accepted all the precautions to avoid electric shock in the connection process - on the control machine / switches to hang the sign "People" work, assign an observer. After that, attach the conductors to the appropriate terminals of the electrical panel - the phase and zero to the main machine (which must be in the off position), and the grounding to the corresponding terminal block.
4. It remains to connect consumers, considering where the wire is laid and its color. Phase wires that are in cables of type of VG, ShVVP, PVS and them are usually marked with black, gray, brown or red insulation, we attach to the lower terminals of single-pole machines. Neutral - blue or white - to zero tires corresponding to the group, and ground wires - yellow-green, green or yellow - to the re.

Initial assembly, tightening contacts can be carried out by means of a battery powerover - so you can save a lot of strength and time. But at the end of the installation operations, it is necessary to make a retreat manually using the most appropriate screwdriver for each specific connection. It is also necessary to remember that in the first weeks as a result of electrothermal impact, contacts are weakened and after approximately one month after the start of intensive operation, it is necessary to control the reliability of each connection, if necessary, tighten. In the future, such a procedure is enough to fulfill every six or twelve months.

If you have any questions about SHR installation technology, you can view one of the many specialized video available on the Internet.

Checking the work of RSh.

Pricing for the installation of the distribution cabinet includes checking the performance of the electrical installation. It is produced by mass (sequential) inclusion of all possible consumers, after which it is necessary to walk throughout the object by checking each rosette with some kind of workable portable electrical appliance. If neither one of the steps does not disable the power of the line, then the installation is carried out correctly.

Then you need to observe for some time for the Rush in the full load mode. If it is observed, smoke, cracking is heard, the smell of Gary is heard, this testifies to unreliable contact in one of the overheating compounds, or on the malfunction of the automation instrument that is required to replace.

In the absence of the above-mentioned phenomena, it is recommended to check the performance of the main nodes that ensure the safety of the operation of the internal electrical system - the RCD. For this purpose, a special tester is used, creating a leakage of the normalized value (10, 30, 300 mA). The price of this instrument is quite accessible even for a private wizard. Some models are equipped with their own control button, when you click on which the device must instantly disconnect.

How much is the work on the installation of Rush

The following factors are directly or indirectly reflected in the installation of the electrical panel: the complexity of the circuit, the number of shield elements and the number of connections that are required to be implemented.

One of the main tasks of operation of the distribution device-maintenance of the necessary reserves by dynamic, thermal stability, bandwidth, in terms of voltage level in the device as a whole and in its separate elements. Performing these tasks can be provided with proper maintenance of distribution devices. During the maintenance, distribution device inspections are carried out, and at the current repair, the observed malfunctions requiring dismantling equipment. Current repairs are performed on the installation site of the equipment, while the faulty parts are replaced, after their replacement, adjust and testing distribution devices.

Periodicity of distribution inspections. The frequency of the inspection is set depending on the type of device, its purpose and the service form. Approximate terms of inspections are as follows:

in distribution devices serviced by replacement personnel, on duty on the substation itself or at home, - daily. With unfavorable weather (wet snow, fog, strong and long rain, ice, etc.), as well as after short circuits and when the signal appears on the ground, additional inspections are carried out on the network. Recommend 1 time a week to inspect the device l in the dark to identify possible discharges of coronation in places of damage to insulation and heating of current-carrying parts;

in distribution devices of substations with a voltage of 35 kV and higher, not having permanent duty personnel, the inspection schedule is depending on the type of device (closed or open) and on the purpose of the substation. In this case, the inspections performs the head of the substation group or the master at least 1 time per month;

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

duty personnel, inspect at least once every six months;

extraordinary inspections on facilities without permanent duty personnel are carried out on time set by local instructions, taking into account the power of short circuit and the condition of the equipment. In all cases, regardless of the short circuit power, the switch is inspected after the unsuccessful automatic re-switching cycle (APV) and disconnect due to short circuit.

About all the faults seen during the inspections of switchgear make an operational journal. Faults that violate the normal operation mode must be eliminated as soon as possible. The health of the backup elements of distribution devices (transformers, switches, tires, etc.) must be regularly verified, including their voltage within the time limits set by local instructions. Backup equipment must be ready at any time to turn on without any preliminary preparation. The frequency of cleaning distribution devices from dust and dirt depends on local conditions. It establishes the chief engineer of the enterprise.

Switch maintenance. External inspections of oil switches without shutdown are carried out with local conditions, but at least once every six months, together with the inspections of the RU. In case of inspection, check: the condition of insulators, fasteners and contact contacts, the oil level and the state of the oil indicators; Lack of leakage of oil from lattice contacts of low-pressure switches or through the tank switches. The oil level at the switches largely determines the reliability of their operation. It should not go beyond the limits of the pointer oil at ambient temperatures from -40 "to +40 ° C. Increased oil level in poles and, accordingly, the reduced volume of the airbag over the oil leads to excessive pressure in the tank when the arc can be caused by the cause of the arc. Destruction of the switch.

Reducing the volume of oil also leads to the destruction of the switch. It is especially dangerous in low-pass switches VMG-10, VMP-10. If leaks are significant and no oils in the oven glass, the switch is repaired and replaced with oil in it. In this case, the load current is torn off by another switch or reduce the load on this connection to zero. The abnormal heating of the exhausting contacts of low-volume switches causes darkening and lifting the oil level in the oil-compliant glass, as well as a characteristic smell. If the tank temperature of the switch exceeds 70 ° C, the switch should be repaired.

Locals with a minimum temperature below 20 ° C, the switches are equipped with automatic devices for heating oil in tanks. At least once every three (six) months, it is recommended to check the switch drives. If there is an ART, testing for shutdown is advisable to carry out from relay protection with off from the APF. If you refuse to trigger the switch must be repaired.

With an outer inspection of air switches, pay attention to its general condition, the integrity of the insulators of quench chambers, separators, shunt resistance and capacitive separators of the support columns and insulating stretch marks, and also in the absence of contamination of the surface of the insulators. According to the pressure makers installed in the distribution cabinet, they check the air pressure in the switch tanks and enter it on the ventilation (in switches operating with the APF, the pressure must be within 1.9 ... 2.1 MPa and in Switches without APF - 1, 6 ... 2.1 MPa). In the switch control circuit, a blocking is provided that prevents the operation of the switch when the air pressure drops below normal.

When inspection, also control the condition and correctness of the devices that signal the on-or-off position of the switch are also controlled. Draw attention to the fact that dampers of exhaust visits of quench cameras are relieved. Visually check the integrity of rubber gaskets in compounds of insulators of quench chambers, separators and their support columns. Control the degree of heating of contact connections of tires and hardware connections. When operating air switches 1-2 times a month from tanks remove accumulating condensate. During the rain period, the air supply increases, with a decrease in ambient air temperature below minus 5 ° C, electric heating in control cabinets and in distribution cabinets. At least two times a year check the operability of the switch by testing testing for shutdown and switching on. To prevent damage to the switches 2 times a year (in spring and autumn), the bolts of all sealing connections are checked and tighten.

Complete switchgear maintenance. Operation of complete distribution devices (CRS) has its own characteristics due to limited sizes of cells. To protect staff from random touch to the current-carrying parts, which is under voltage, locking is provided. In stationary Crues block the mesh doors, which are open only after turning off the switch and disconnectors of the attachment. In the KRU, there are automatic curtains that closing access to the fixed disconnecting contacts compartment when the trolley is switched out. In addition, there is an operational blocking, preventing personnel when performing erroneous operations. For example, turning out the trolley into the test position is allowed only after turning off the switch, and pumping the trolley to the operating position - when the position of the switch and ground knives is turned off. Observation of the equipment lead through viewing windows and mesh fences or observation hatches closed by a protective grid.

Write inspections without turning off their schedule, but at least once a month. In case of inspection, check the operation of lighting networks and heating of rooms and cabinets of CRS; state of switches, drives, disconnectors, primary disconnecting contacts, blocking mechanisms; Pollution and lack of visible damage to insulators; state of secondary switching chains; Action of switch control buttons. Systematically, depending on local conditions, isolation from dust and pollution is purified, especially in the Outdoor Circular (CRN). In case of inspections of the complete switchgear of CRS and CRN, pay attention to the state of seals in the joints of the joints of the elements of the metal structures; Control of equipment connection to the ground contour; availability of safety and fire extinguishing; work and serviceability of heating devices of cabinets CroNe; the presence, sufficiency and normal color of the oil in the switches; state of mounting compounds; heating of current-handing parts and devices; Lack of extraneous noise and odors; Feed alarm, lighting and ventilation. Simultaneously with the inspection, the correct position of the commuting devices is verified. Built-in and crucible equipment inspecting in accordance with operating instructions.

When operating the RC, it is forbidden to unscrew the removable details of the cabinet, lift and open automatic curtains in the presence of voltage in those places that are closed with them. In the cabinets of the roll-out type for grounding of exhaust lines with the help of disconnectors embedded in KRU, 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 ground disconnector, put the trolley into the test position.

Fuses in the cabinet of the transformer of their own needs can be changed only when the load is removed. When carrying out the work within the compartment of the tipping trolley on the automatic curtain, you must post warning posters: "Do not include! People work "," High Voltage! Life threatening!" Drop the trolley with the switch and install it in the working position can only prepared operational staff.

Over the trolley in the working position is allowed only when the ground disconnector is disconnected.

Service disconnectors. When adjusting the mechanical part of three-pole disconnectors check the simultaneousness of the knives. When adjusting the moment of touch and compression of movable knives, the length of the thrust or stroke of the limiters and the stubborn washers or slightly move the insulator on the basement or sponges on the insulator. With full inclusion, the knife should not reach the contact site by 3-5 mm. The smallest effort of pulling one knife from a fixed contact should be 200 H for disconnectors for nominal currents of 400 ... 600 A and 400 H for disconnectors for nominal currents of 1000 ... 2000 A. The density of adjustment of the disconnector contacts is controlled by constant current resistance, which should There are within the next limits: for RLD (35 ... 220 kV) disconnectors for rated current 600 A - 220 μm; For other types of disconnectors for all voltages with a nominal current of 600 A - 175 μm, 100 A - 120 μm; 1500-2000 A - 50 μC.

Contact surfaces of the disconnectors in the process of operation are lubricated with a neutral vaseline with admixture of graphite. The driving parts are covered with non-freezing lubrication. The state of disconnectors insulators is estimated by insulation resistance, voltage distribution on steel elements of pin insulators or by the results of the test of the insulator with an increased voltage of industrial frequency.

Block-contacts of the drive, designed to signal and block the position of the disconnector, must be set so that the disconnector turning off the disconnector starts to operate after passing the knife 75% of the total stroke, and the signal on the connection is not earlier than the torque of the still contacts knife.

Maintenance of short-circuit and separators. Shortgarters - devices designed for artificial creation of short circuit in cases where the current during damage to the transformer may be insufficient for relay protection. The short-circuit is activated by automatic drive when the relay protection is triggered, and it turns off manually.

When the power transformers are disconnected without load, and the automatic shutdown of damaged transformers is used by separators. Disable the separator is automatically or manually, turned on - only manually with a removable handle. On connectors 35 ... 11o kV with sequentially installed separators and disconnectors, turning off the magnetizing current of transformers and capacitive current currents should be performed by separators. Telers for 35 kV is allowed to shut down the current of the closure to Earth to 5 A.

On average, 10 km of 35 kV charging current is 0.6 A and the ground short circuit current 1 A.

Shortgarters and separators inspect at least 2 times a year, as well as after emergency shutdowns. In case of inspection, special attention is paid to the state of insulators, contacts, grounding wire skipped through the current transformer window. When traces of burning, contacts are cleaned or replaced. The duration of the moving parts of the short-circuit on the voltage 35 and 110 kV from the pulse supply to the contact of the contacts should be no more than 0.4 s, and the separator from the pulse feed to the opening of the contacts, respectively, 0.5 and 0.7 s.

In the course of operation of short-circuits and separators, special attention should be paid to the most unreliable nodes: open or insufficiently protected from possible pollution and icing springs, contact systems and hinge compounds, as well as unprotected bearings protruding from the back side.

During the adjustment of the short-circuit and the separator, pay attention to the reliable triggering of the separator relay (bro), which is designed for currents of 500 ... 800 A. Therefore, at short circuit currents, less than 500 and the ground bus should be replaced with wire and skip it through the current transformer several times . If this is not done, the BRO relay will tighten the anchor to fuzzly and thereby release the locking mechanism of the separator to turn off the short circuit current. Premature disabling separators is one of the reasons for their destruction.

The current repair of disconnecting devices, as well as the test of their actions (testing), is carried out as needed within the deadlines set by the chief engineer of enterprises. The scope of work on current repairs includes: external inspection, cleaning, lubrication of rubbing parts and measuring the resistance of contacts of the DC. Unplanned repairs are performed in case of detection of external defects, heating contacts or unsatisfactory insulation state. The adjustment of the short-circuit and the separator consists in checking the drive operation to switch on and off, checking the position of the knives and a shut-off plant of the drive with a blocking BRO relay, adjusting the stroke of electromagnets and relays.

Monitoring the status of current-carrying parts and contact compounds. The state of the current-handing parts and contact connections and switchgear devices are tested during inspections. The heating of the detachable compounds in closed distribution devices is controlled using electrothermometers or heat and thermal radicals. The electrothermometer action is based on the principle of temperature measurement using a thermistor, glued to the outer surface of the sensor head and a closed copper foil. The heating temperature of the contact compounds is determined by a set of heatmes with different melting temperatures. As thermal indices, reversible repels of repeated action, which, with long heating, change their color. The thermal radicalator must withstand, not destroying, at least 100 color changes with long 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 RPR recommendations.

On the section of grounding devices subject to intensive corrosion, set more frequent measurement frequency. Unplanned measurements of resistance of grounding devices are carried out after their reorganization or overhaul. Resistance to grounding devices is measured by special MS-08, M-416, F4103 devices or a voltmeter ammeter method. Circuit diagrams of inclusion of devices MS-08, M-416, F4103 are shown on the lids of instruments or in the instructions. Metal rods with a diameter of 12 ... 16 mm are used as auxiliary earthing, which are clogged into the ground to a depth of 0.5 m at a distance specified in the instructions.

SchemeTechnologicalRepair processTransformer

The most vulnerable and often damaging part of the transformer is its winding of the VN and less often NN. Damage most often arise due to a reduction in the electrical strength of isolation on any section of the winding.

In transformers, inputs, switches, lid and other parts can also be damaged. An approximate ratio of damage to individual parts of the transformer as follows:

winding and conductive parts - 53%;

switches -12%;

all other parts taken together - 17%.

Studies of the causes of emergency yields of transformers have shown that usually accidents occur due to unsatisfactory maintenance and poor repair quality.

The transformer with damaged windings or its other parts is subject to immediate conclusion from work and repair. The enterprise consists of a receivable act with the application of the defects of defects and draw out the order. The documents record the order number, passport details, customer requirements, external inspection results, test tests and measurements. All defects found in the future process of disassembling the transformer also enter the defect statement. According to these data, determine the volume of repair work.

The most common technological scheme for the repair of three-phase transformers with oil cooling is shown in Figure 16.1.

In accordance with this scheme, a damaged transformer, which is in the warehouse of faulty transformers, enters a defective preparatory department consisting of three sections - disassembly and washing, diagnostics of windings and a mechanical part of the transformer. On the disassembly section, the transformer is cleaned, the oil is drained from its expander, tank and oil-filled inputs, and then, making sure of entries in the accompanying documents and from preliminary tests in the transformer malfunction, switch to its disassembly.

Damage to the external parts of the transformer (expander, tank, reinforcement, the outer part of the inputs, the punching fuse) can be revealed to careful inspections, and internal parts - various tests. However, test results do not always allow to accurately establish the actual nature of damage, since any deviation from the norm detected as a result of tests (for example, an increased idle current) can be caused by various reasons, including a turn-in circuit in the winding, the presence of a closed current circuit through Coupling bolts and pressing parts, incorrect inclusion of parallel windings, etc. Therefore, in the diagnostic process, as a rule, the transformer disassembles and, if necessary, raise the active part, which allows not only to accurately establish causes, nature and scope of damage, but also determine the required transformer Materials, tools and fixtures, as well as time.

DisassemblyANDDefinitionFaults

The sequence of disassembly operations in each case depends on the construct of the transformer to be repaired. The repair of modern transformers of domestic production, differing in power and constructive execution, and transformers of the issuers of the previous years, as well as foreign firms produced and currently produced and currently supplied, therefore recommend that any unified technological sequence of disassembering and repair operations of all incoming transformers It is impossible.

Before disassembly, the completeness of the transformer received in the repair of the transformer (all assembly units and parts should be available, relying for this design), as well as the compound of its outer parts, the integrity of welding seams and compounds, the absence of leakage of oil from flange compounds of reinforcement with tank.

First stage of disassembly. Disassembly begin with dismantling a gas relay, a thermometer, an expander, safety pipe and other devices and parts located on the transformer lid.

Relelling the relay, the safety pipe and the extender, continue to disassemble, turning to the dismantling of the transformer cover, which is carried out in compliance with precautions that exclude damage to the porcelain parts of the introduction of VN and NN. The bolts taken from the entire perimeter of the lid, together with the washers kicked on them and were washed with nuts on their threads, coated with anti-corrosion lubricant and, putting into drawers, stored for reuse when assembling the transformer.

The lid lifted from the bolts for lifting frogs, screwed onto the speckters of the threaded ends of the lifting spills, fixed on the yoke beams of the upper yard of the magnetic pipeline. Transformers with power up to 4uu kV and usually have two lifting fish, greater power - four. For lifting the active part, special devices and slings are used, designed for a mass of the lifted cargo and the necessary tests. When dismantling radiators and other large parts of the outdoor transformer, an auto 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 raise the active part of the transformer. The active part raised from the tank is installed on a solid platter from outcanned boards or on wooden bars so as to ensure its stable vertical position and the ability to inspect, check and repair.

Continuing the disassembly, disconnect the taps from the inputs and the switch and check the state of their insulation, reinforcement seams of the input and contact system of the switch (all selected faults are fixed). Further, fish are rejected with vertical studs, remove the cover, belong to the side and laid so that the testers under the cover are not damaged, the inputs are protected from mechanical damage, closing them with rigid cylinders from cardboard or wrapped with clean bags.

The second stage of disassembly, the most complex and time-consuming, - dismantling the windings, the basic operations of which are performed in such a sequence: remove vertical studs, screw the nuts of the tie bolts and remove the tape bright beams of the magnetic pipeline, discrepate the upper yarm of the magnetic pipeline, tying and placing packets in order at which they will be more convenient Stasted with the above-mention of the top of the yoke. Next, disassemble the windings, remove the taps, remove the wooden and cardboard parts of the opening of the windings of the VN and NN and remove windings with the rods manually winding the transformer with a capacity of up to 63 sq. A) or with the help of a lifting mechanism (winding transformers with a power of 100 kV a and above) - at first and then NN.

After disassembling the transformer examine its external part. At the same time check the purity of the windings, paying particular attention to the channels between windings and magnetic wires. Reveal to the touch the places of weakening turns. In these places, as a rule, insulation of the winding, charred as a result of inter-touch closures, invisible from the outside is insulated. Check the external inspection The condition of isolation, the absence of deformations and displacement of windings or its turns, the presence of insulating gaskets, wedges, struts.