Repair of power transformers. We repair power transformers Technological map of current transformer repair
TYPICAL TECHNOLOGICAL CARD
INSTALLATION OF POWER TRANSFORMERS WITH NATURAL OIL COOLING, VOLTAGE UP TO 35 kV, POWER UP TO 2500 kVA
1 AREA OF USE
A typical technological map has been developed for the installation of power transformers.
General information
Requirements for transportation, storage, as well as for installation and commissioning of power transformers are defined by the instruction "Transportation, storage, installation and commissioning of power transformers with voltage up to 35 kV inclusive without revision of their active parts" and guiding technical instructions "Power transformers, transportation , unloading, storage, installation and commissioning".
The power transformer, which arrived from the equipment supplier (manufacturer, intermediate base), is subjected to external inspection. During the inspection, they check the presence of all places according to the railway bill, the condition of the packaging, the absence of oil leaks at the joints of the radiators with the tank and in places of seals, the integrity of the seals, etc.
The packaging of dry transformers must ensure their safety from mechanical damage and direct exposure to moisture.
If a malfunction or damage is detected, an act is drawn up, which is sent to the plant or intermediate base.
After the inspection and acceptance of the transformer, they begin to unload it.
It is recommended to unload the transformer with a bridge or mobile crane or a stationary winch of the appropriate carrying capacity. In the absence of lifting means, it is allowed to unload the transformer onto the sleeper stand using hydraulic jacks. Unloading of transformer units (coolers, radiators, filters, etc.) is carried out by a crane with a lifting capacity of 3 to 5 tons. .
To lift the transformer, special hooks are provided on the walls of its tank, and eyelets (lifting rings) are provided on the roof of the tank. Slinging of cables for large transformers is carried out only by hooks, for small and medium ones - by hooks or eyelets. Studs and lifting ropes used for lifting must be made of steel rope of a certain diameter corresponding to the mass of the transformer. To avoid cable breaks, wooden linings are placed under all sharp edges of the bends.
The heavy-weight transformer arriving disassembled is unloaded using a heavy-duty railway crane. In the absence of such a crane, unloading is carried out using winches and jacks. To do this, the transformer tank installed on the railway platform is first lifted with two jacks by the lifting brackets welded to the bottom and walls of the tank, then a trolley supplied separately from the tank is brought under the tank, and with the help of winches the tank is rolled off the platform onto a specially prepared sleeper cage. Rolling is carried out along steel strips placed under the trolley rollers. The remaining components of the transformer (expansion tank, outlets, etc.) are unloaded with conventional cranes.
The unloaded transformer is transported to the installation site or to the workshop for revision. Depending on the mass of the transformer, transportation is carried out by car or on a heavy trailer. Carriage by dragging or on steel sheet is prohibited.
Vehicles used for the transportation of transformers must have a horizontal cargo platform that allows free installation of a transformer on it. When the transformer is located on the vehicle, the major axis of the transformer must coincide with the direction of travel. When installing a transformer on a vehicle, it is necessary to take into account the location of the inputs on the transformer in order to prevent a subsequent turn before installation at a substation.
Dismantled components and parts can be transported together with the transformer, if the carrying capacity allows vehicle and if at the same time the requirements for transportation of the transformer itself and its components are not violated.
The carrying capacity of the vehicle must not be less than the mass of the transformer and its elements in case of their transportation together with the transformer. It is not allowed to apply traction, braking or any other types of forces to the structural elements of the transformer during their transportation.
Figure 1 shows a diagram of the installation of a transformer on a car.
Fig.1. Scheme of installation and fastening of the transformer on the car
In some cases, prior to installation, transformers are stored for a long time in on-site warehouses. Storage must be organized and carried out in such a way as to exclude the possibility of mechanical damage to transformers and dampening of the insulation of their windings. These requirements are met by certain storage conditions. Depending on the design and method of shipment of transformers, their storage conditions will be different. In all cases, it is necessary that the duration of storage of transformers does not exceed the maximum allowable established by the instructions mentioned above.
The storage conditions of power transformers with natural oil cooling are accepted according to the group of storage conditions of the OZHZ, i.e. in open areas.
Storage conditions for dry non-sealed transformers must comply with the conditions of group L, transformers with a non-combustible liquid dielectric - group OZH4. Storage conditions for spare parts (relays, fasteners, etc.) for all types of transformers must comply with condition group C.
Dry-type transformers must be stored in their own enclosures or original packaging and must be protected from direct exposure to atmospheric precipitation. Oil transformers and transformers with non-combustible liquid dielectric must be stored in their own tanks, hermetically sealed with temporary (during transportation and storage) plugs and filled with oil or liquid dielectric.
When storing transformers up to 35 kV inclusive, transported with oil without expanders, the installation of the expander and adding oil must be done as soon as possible, but no later than after 6 months. When storing transformers with a voltage of 110 kV and above, transported without an expander with oil and without oil, the installation of the expander, topping up and filling with oil should be carried out as soon as possible, but no later than 3 months from the date of arrival of the transformer. The oil must comply with the requirements of the PUE. The oil level must be periodically monitored (when the level drops, it is necessary to add oil), at least once every 3 months it is necessary to take an oil sample for a reduced analysis. The absence of oil leakage from the transformer tank is checked periodically by traces on the tank and fittings. Sealed oil transformers and transformers with non-flammable liquid dielectric must be stored in the manufacturer's packaging and protected from direct precipitation.
2. ORGANIZATION AND TECHNOLOGY OF WORK PERFORMANCE
INSTALLATION OF POWER TRANSFORMERS WITH NATURAL OIL COOLING
The facilities mainly use power transformers with natural oil cooling, voltage up to 35 kV, power up to 2500 kVA. The scope of work for the installation of a power transformer with natural oil cooling depends on whether it comes from the factory - assembled or partially disassembled. Regardless of the type of delivery, the sequence of installation operations will be the same.
When installing a power transformer, it is necessary to perform the following operations in sequence:
Accept a room (installation site) and a transformer for installation;
Inspect the transformer;
Dry the windings (if necessary);
Assemble and install the transformer in place.
Acceptance for installation of a room (installation site) and a transformer
The room (open area) for the installation of the transformer must be completely completed by construction. Lifting devices or portals must be installed and tested prior to installation of the transformer.
As you know, the supply of power transformers and their delivery to the installation area must be carried out by the customer. When accepting transformers for installation and determining the possibility of further work, the whole range of issues related to transportation and storage, the condition of transformers for external inspection and determination of insulation characteristics, readiness and equipment of the room or installation site are considered.
The customer must submit the following required information and documents:
Date of dispatch of transformers from the manufacturer;
Conditions of transportation from the manufacturer (by rail or other transport, with or without oil, with or without expander);
Certificate of acceptance of the transformer and components dated railway;
Scheme of unloading and transportation from the railway to the installation site;
Storage conditions for transformers and component parts (oil level in the transformer, period for filling and topping up oil, characteristics of filled or topped-up oil, results of transformer insulation assessment, oil sample tests, leak tests, etc.).
At the same time, the condition of the transformer is assessed by external inspection, the results of the transformer tightness test and the condition of indicator silica gel.
During an external examination, they check for dents, the safety of the seals on the taps and plugs of the transformer.
The tightness of the transformer is checked before installation, before topping up or pouring oil. The seals must not be tightened before the tightness test. The tightness of transformers transported with an expander is determined within the limits of the oil indicator marks.
The tightness test of transformers transported with oil and a dismantled expander is carried out by pressure of an oil column 1.5 m high from the level of the cover for 3 hours. transformer. It is allowed to check the tightness of the transformer by creating an excess pressure of 0.15 kgf/cm (15 kPa) in the tank. The transformer is considered sealed if, after 3 hours, the pressure drops to no more than 0.13 kgf/cm (13 kPa). Checking the tightness of transformers transported without oil, filled with dry air or inert gas, is carried out by creating an excess pressure of 0.25 kgf / cm (25 kPa) in the tank. The transformer is considered sealed if the pressure drops after 6 hours to no more than 0.21 kgf / cm (21 kPa) at a temperature environment 10-15 °С. The creation of excess pressure in the transformer tank is carried out by pumping dry air through a silica gel dryer with a compressor or by supplying dry inert gas (nitrogen) from cylinders to the tank.
Acceptance of transformers for installation is documented by an act of the established form. Representatives of the customer, assembly and commissioning (for transformers of size IV and above) organizations participate in the acceptance.
revision
An audit of power transformers is carried out before installation in order to check their condition, identify and timely eliminate possible defects and damage. The audit can be carried out without inspection of the removable (active) part or with its inspection. All transformers subject to installation are subject to audits without inspection of the removable part. An audit with an inspection of the withdrawable part is carried out in cases of detection of damage to the transformer, which cause assumptions about the presence of internal faults.
Transformers currently produced have additional devices that protect their removable part from damage during transportation. This makes it possible, under certain conditions of storage and transportation, not to carry out a laborious and expensive operation - an audit with a lift of the removable part. The decision to install transformers without revision of the withdrawable part should be made on the basis of the requirements of the instructions "Transportation, storage, installation and commissioning of power transformers for voltage up to 35 kV inclusive without revision of their active parts" and "Power transformers. Transportation, unloading, storage, installation and commissioning. At the same time, a comprehensive assessment of the fulfillment of the requirements of the instructions is carried out with the execution of the relevant protocols. If the requirements of the instructions are not met or faults are detected during external inspection that cannot be eliminated without opening the tank, the transformer is subject to revision with an inspection of the removable part.
When carrying out an audit without inspecting the removable part, a thorough external examination of the transformer is carried out, an oil sample is taken for dielectric strength testing and chemical analysis; measure the insulation resistance of the windings.
During the inspection, check the condition of the insulators, make sure that there are no oil leaks at the seals and through the welds, that the required oil level is present in the expander.
The electric strength of the oil, determined in a standard vessel, should not be less than 25 kV for devices with higher voltage up to 15 kV inclusive, 30 kV for devices up to 35 kV and 40 kV for devices with voltage from 110 to 220 kV inclusive.
Chemical analysis of transformer oil is carried out in special laboratory, and the correspondence is determined chemical composition oils to the requirements of GOST.
The insulation resistance of the windings is measured with a megaohmmeter for a voltage of 2500 V. The insulation resistance is measured between the windings of higher and lower voltages, between each of the windings and the housing. For oil transformers with higher voltage up to 35 kV inclusive and power up to 6300 kVA inclusive, insulation resistance values measured at the sixtieth second () must be at least 450 MΩ at +10 °C, 300 MΩ at +20 °C, 200 MΩ at +30 °C, 130 MΩ at +40 °C. The value of the absorption coefficient must be at least 1.3 for transformers with a power of up to 6300 kVA inclusive.
The physical essence of the absorption coefficient is as follows. The nature of the change in the measured value of the winding insulation resistance over time depends on its condition, in particular, on the degree of moisture. To understand the essence of this phenomenon, we use the equivalent circuit of the winding insulation.
Figure 2 shows the insulation resistance measurement circuit and the equivalent circuit. In the process of measuring the insulation resistance with a megohmmeter, voltage is applied to the insulation of the winding direct current. The drier the winding insulation, the greater the capacitance of the capacitor formed by the winding conductors and the transformer case, and therefore, the greater the charge current of this capacitor will flow in the initial measurement period (at the fifteenth second from the moment the voltage is applied) and the megohmmeter readings will be smaller ( ).
In the next measurement period (at the sixtieth second), the capacitor charge ends, the charge current decreases, and the megohmmeter reading increases () .
The drier the insulation of the windings, the greater the difference in the readings of the megohmmeter in the initial () and final () periods of measurement and, conversely, the wetter the insulation of the transformer windings, the smaller the difference in these readings. 
6. TECHNICAL AND ECONOMIC INDICATORS
State budget standards.
Federal unit rates for equipment installation.
Part 8. Electrical installations
FERM 81-03-08-2001
Order of the Ministry of Regional Development of Russia dated 04.08.2009 N 321
Table 08-01-001. Power transformers and autotransformers
Meter: pcs.
| Price code | Name and technical specifications equipment or types of mounting | Direct costs, rub. | Including, rub. | Labor costs of workers - installers, man-hour |
|||
| Wages of workers installers | machine operation | mate- rials | |||||
| Total | including the wages of the workers who operate the machine | ||||||
| Three-phase transformer: |
|||||||
| 08-01-001-06 | 35 kV with a capacity of 2500 kVA | 7018,51 | 2635,88 | 3748,71 | 360,72 | 633,92 | 274 |
BIBLIOGRAPHY
SNiP 3.03.01-87. Bearing and enclosing structures.
SNiP 12-03-2001. Labor safety in construction. Part 1. General requirements.
SNiP 12-04-2002. Labor safety in construction. Part 2. Construction production.
GOST 12.2.003-91. SSBT. Production equipment. General safety requirements.
GOST 12.3.009-76. SSBT. Loading and unloading works. General safety requirements.
GOST 12.3.033-84. SSBT. Construction vehicles. General safety requirements for operation.
GOST 24258-88. Scaffolding tools. General specifications.
PPB 01-03. Rules fire safety in Russian Federation.
The electronic text of the document was prepared by CJSC "Kodeks"
and verified according to the author's material.
Author: Demyanov A.A. - Ph.D., teacher
Military Engineering and Technical University,
St. Petersburg, 2009
The results of the analysis of the organization of labor and measures to improve it.
Technological maps provide a detailed technically sound description of operations for the current repair of equipment of traction substations, substations and PPS and must be strictly observed when performing work. They define the categories of work in relation to security measures, the composition of the performers and their qualifications, set out the basic requirements that ensure the safety of personnel. The number of performers and security measures in the preparation of the workplace are specified by the order (order) issued for the production of work.
The name of the position of an electrician in this collection is accepted in accordance with the Qualification characteristics and categories of remuneration for positions of managers, specialists and employees according to the industry tariff scale (approved by the indication of the Ministry of Railways dated 10/18/96 No. A-914u) and the Collection of changes and additions to qualification characteristics and payment categories labor positions of managers, specialists and employees according to the industry wage scale (Moscow, PVC of the Ministry of Railways of the Russian Federation, 1999). The name of the profession and the category of qualification of an electrician of a traction substation - according to the Unified Tariff and Qualification Reference Book of Works and Professions of Workers (ETKS), Issue 56 and the Collection of Tariff and Qualification Characteristics of the Professions of Workers Employed in Railway Transport (Moscow, PVC MPS RF, 1999).
When performing the work provided for in the collection, instruments, tools and devices manufactured by the electrical industry and designed specifically for work in electrical installations of traction substations are used. Recommended lists of them are given in each technological map. In addition to the recommended ones, other types of devices with similar or close characteristics can be used.
Performers must be provided with the necessary tools, devices and fixtures that meet the technical conditions. They are cared for by the personnel performing the main work.
All service personnel involved in the processes must have sufficient experience and pass the safety test.
The limits of numerical indicators given in the collection, in which “up to” is indicated, should be understood inclusively, “not less than” - are the smallest.
When this collection is published, the collection “Cards of technological processes for capital, current repairs and preventive tests of specific equipment of traction substations of electrified railways”, approved on 14.01.94 by the Ministry of Railways of the Russian Federation, No. TsEE-2, becomes invalid.
2. Transformers Routing № 2.1.
Current repair of power transformers10000 - 63000 kVA1. Cast
Electromechanic - 1
Traction substation electrician 4th category - 1
Traction substation electrician 3rd category - 1
2. Terms of work
The work is being done:
With stress relief
Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Safety helmets, safety belt, ladder, grounding, shorts, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, stopwatch, thermometer, level, pump with pressure gauge and hose, wrenches, combination pliers, screwdrivers, scraper, brushes, container for draining sediment, glass containers with a ground stopper for oil sampling, indicator silica gel, silica gel, transformer oil, TsIA-TIM lubricant, white spirit, moisture-oil-resistant varnish or enamel, spare oil-indicating glasses, rubber gaskets, cleaning material, rag
4. Preparatory work and admission to work
On the eve of the work, submit an application for taking the transformer out for repair.
Check the serviceability and expiration dates of protective equipment, devices, prepare tools, mounting devices and materials.
After issuing the work order, the work foreman should be instructed by the person who issued the work order.
4.4. Operational personnel to prepare the workplace. For the foreman to check the implementation of technical measures for the preparation of the workplace.
Get the team to work.
The foreman should instruct the members of the team and clearly allocate responsibilities between them.
End of technology card№ 2.2.
|
Oil change in hydraulic seals of oil-filled bushings a silica gel in moisture-absorbing cartridges (see fig. 2.1.1 ., fig. 2. 1 .3.) |
The condition of the silica gel in the desiccant cartridges is determined by the color of the indicator silica gel. If the color changes from blue to pink, replace the silica gel in the cartridges and the oil in the water seal. Replace Siliga gel in dry weather, taking the dryer out of operation for no more than one hour. Check the oil level in the hydraulic seal. The replacement of silica gel is carried out as follows: disconnect the cartridge from the input, replace the silica gel, having previously cleaned the cartridge of contamination, change the oil in the hydraulic seal, attach the cartridge to the input |
|
|
Checking the working condition of the cranes and dampers of the transformer |
Check the compliance with the working position of devices, valves, dampers. Carry out an inspection with checking the oil level in the bushings and tanks of the transformer. Record readings of thermal alarms, oil level indicators, air temperature, position of switches of all windings |
Note. All operations with oil filled and 110-220 kV bushings must be carried out in cooperation with a RRU specialist.
Removing the transformer from the electric locomotive (work is done after removing the small removable roof and cooling fans of the traction transformer)
1.1 Disconnect all shunts and busbars from the traction transformer, stage switch and instrument cabinet.
1.2 Disconnect the cables and low-voltage wires from the substation and the instrument cabinet, having previously checked their marking. If there is no marking, restore, if the marking is incorrect, re-mark.
1.3 Loosen the bolts securing the transformer to the frame of the locomotive body. Remove fence nets.
1.4 Moor the traction transformer with a 30-ton overhead crane and move it to the transformer compartment on a transport trolley
Preliminary tests of the transformer.
2.1 Install the transformer in the test station
2.2 Measure the insulation resistance of all windings in accordance with clause 11.2.1.
2.3 Measure the ohmic resistance of the windings in accordance with clause 11.2.2.
2.4 Test the dielectric strength of the winding insulation in accordance with clause 11.2.4.
2.5 Make experience x.x. similarly to clause 11.2.6.: at a voltage of 62.5 V, the losses should not exceed 2.3 kW.
When testing, set possible faults and determine the extent of the repair. If necessary, repair the active part.
Disassembly of the traction transformer.
3.1 Place the transformer in the repair position
3.2 Clean the traction transformer from dirt and dust.
3.3 Drain the oil from the traction transformer, stage switch and expansion tank.
3.3 Remove the substation, instrument cabinet and oil pumps from the transformer and transfer them for repair.
3.4 Remove BF50/10 gas switch, air dryer, flow meters, thermostats and expansion tank.
3.5 Remove the separating plate.
3.6. Remove assembly hatch covers, disconnect current transformers, inputs.
3.7 Remove bushings m1-m4.
3.8 Loosen the bolts securing the bell to the transformer tank.
3.9 Moor with an overhead crane and remove the bell.
3.10. Dismantle the cooling system.
Repair of the active part of the transformer (magnetic circuit and windings).
4.1 Check the condition of the insulation of the accessible turns of the coils, leads, contamination of the surfaces of the windings, the magnetic circuit and the leads with oil deposits, as well as the dimensions of the cooling channels.
4.2 Check the condition of the fastening, wedging and compression of the windings, the condition and fastening of the insulating gaskets between the coils, serviceability electrical connections, no traces of overheating, overlapping, no deformation and displacement of coils and gaskets.
4.3 Loose fastening of the windings should be restored by tightening the pressure bolts or placing wedging inserts made of getinax between the pressure plate and the yoke sheets. Tighten the pressure bolts with a torque wrench with a torque of 12-13 kg / cm. After tightening the bolts, cotter with wire.
4.4 Tighten the bolts at the bottom of the tie-down frame on both sides of the bottom of the tank. If necessary, install a fiberglass gasket between the tie-down frame and the magnetic circuit. The tightening torque of the bolts should be 5-6 kg/cm.
4.5 Bulging winding coils in the absence of open circuits, interturn short circuits and satisfactory insulation resistance relative to the body and other windings, it is allowed to fill in the original position with light hammer blows through a wooden gasket.
4.6 Check the insulation resistance of the tie rods with respect to the magnetic circuit with a 1000 V megger.
4.7. Check the serviceability of the grounding of the magnetic circuit, the serviceability of the fastening of the grounding shunt between the sheets of the magnetic circuit, the absence of traces of heating and melting of the shunt and iron of the magnetic circuit.
4.8 Clean the contacts of the 25/12kV switch, check their pressing and fit, check the fastening of the cables, set the switch to the “25kV” position.
4.9 Insulating plates for autotransformer terminals and secondary windings clean the transformer from dirt, degrease, inspect, replace defective ones.
4.10 Inspect the current transformers, check the fastening, the integrity of the windings, the absence of cracks, melting and other damage.
4.11 Remove the inlets on the tank cover, clean, inspect, replace the seals. Replace cracked bushings. It is allowed to repair bushings D25, D1 type Kkr37 / 63O according to the manufacturer's technology in accordance with the Rules for the care of the transformer kit.
4.12 Remove oil deposits from the surfaces of the windings, terminals, magnetic circuit and from the cooling channels. Use of wooden scrapers is allowed. Rinse the transformer with clean, dry transformer oil.
4.13 Clean the transformer tank, expander and cooling system from sludge and sediment, rinse with clean warm dry transformer oil. Clean the outer part of the coolers from dust and dirt, degrease with gasoline.
4.14 Inspect the inner walls of the tank and its roof, check the color strength of the inner surface. Sand the areas with peeling paint and paint with epoxy ester primer. Check the condition of welding of the installation chambers inside the tank for installing the magnetic rod, the serviceability of the felt pads under the paws of the magnetic rod, and the devices for attaching the core to the tank.
4.15 Check the condition of oil pipelines, their valves, valves and seals, replace or repair defective ones. Inspect welds, cut out defective ones and repair.
4.16 The active part of the transformer must be in the air for no more than 24 hours at an air humidity of not more than 75%.
Repair of transformer cooling radiators.
5.1 Prepare radiators for testing. Install clamps to prevent deformation. Assemble the inlet flange compressed air. Close the opposite flange tightly.
5.2 Connect the pressure hose with pressure reducing valve to the radiator flange.
5.3 Immerse the radiators in a tank with water heated to 60 0 С.
5.4 Test the radiators with an air pressure of 2.5 atm.
5.5 Dismantle test devices on serviceable radiators. Rinse radiators with transformer oil and hand over for assembly.
5.6 Remove the defective radiator from the radiator set. Install the blind flange on the radiator. Immerse the radiator in a tank with water heated to 60 0 C and test individual pipes with an air pressure of 2.5 atm. Mark the places of defects. Remove the radiator from the fixture and seal the defective pipes tightly on both sides with tin. In one radiator, it is allowed to close up no more than 5% of the tubes.
5.7 After repair, assemble a set of radiators and repeat the tests in paragraphs 5.1.-5.5.
Drying of the transformer windings is carried out when the insulation resistance of the windings is below the standard values or when the active part is in the air for more than 24 hours.
6.1 Move the transformer to the drying cabinet.
6.2 Turn on the cabinet heating and, with the cabinet lid ajar, heat the transformer to a temperature of 85-95 0 С with a temperature rise rate of not more than 60 0 С/hour.
The temperature is controlled by thermoelements installed at 2 points: on one of the coils at the top between the insulation cuffs and on the plate for the magnetic circuit coupler.
6.3 After reaching the transformer temperature of 85-95 0 C, close the cabinet and dry the transformer in a vacuum. The increase in vacuum is not more than 0.25 atm/hour (0.025 MPa/hour).
After reaching a vacuum of 0.00665-0.000133 atm. (665-13.3 Pa) dry for 28 hours. at a temperature of 85-95 C.
With TR-3, drying is allowed at a vacuum of at least 5320 Pa (0.0532 atm).
6.4 The end of drying is the moment when the insulation resistance of the windings exceeds the standard values and practically stops increasing. The condensate outlet should be no more than 0.5 l/h.
6.5. At the end of drying, stop heating and eliminate the vacuum at a rate of not more than 0.01875 MPa/hour (0.1875 atm/hour).
6.6 After drying, tighten the fastening of the windings with pressure bolts with a torque of 12-13 kgf / m, if necessary, put a gasket made of getinax between the pressure plate and the magnetic circuit. Tighten and cotter the connecting bolts, tubes, holders.
6.7 Check the condition of the insulation of the tie rods of the magnetic circuit with a 1000 V megger.
6.8 Move the transformer to the assembly tank.
6.9 With TR-3, it is allowed to dry the transformer in its own tank by short-circuiting the traction winding. Short circuit current should not be more than half the rated current of the traction winding.
Transformer assembly.
7.1 Check the insulation resistance of the windings relative to each other and relative to the housing:
high-voltage winding (Do, D1, D25) - 100 MΩ;
traction windings (m1-m4) - 20 MΩ;
heating winding (C1-C2) - 10 MΩ;
auxiliary winding (E-J) - 5 MΩ.
7.2 Assemble the tank: cooling system, inlets, insulating plates, stage switch, 25/12.5 switch, current transformers, assembly hole covers, expansion tank.
When assembling, install new seals made of oil-resistant rubber.
7.3 Fill the transformer with oil.
Open one uppermost air outlet. Fill the tank from the bottom side with dry warm transformer oil, heated to 70 0 С.
When the transformer temperature is less than 60 0 C, it is necessary to heat the transformer by circulating warm oil between the transformer and the filter device until the temperature of the transformer and oil is equal. For heating, set the circulation rate to 450-600 l/h for 7 hours.
7.4 After installing the BF50/10 gas relay and air dryer, fill the transformer with oil through the expansion tank.
7.5 Bleed air from the tank at 12 points.
7.6 Bleed oil with pumps for 2 hours, then bleed air again at 12 points.
7.7 Leave the transformer for 2 days, then bleed the air at 12 points.
Air dryer repair.
8.1 Dismantle the air dryer removed from the transformer.
8.2 Inspect the parts of the air dryer, replace the unusable ones.
8.3 Regenerate the drying agent.
Pour the drying agent into a clean lining with a layer of no more than 10 mm.
Heat up in drying chamber drying agent and dry at a temperature of 120-180 0 C for 3 hours.
The end of drying is a change in color from pink to bright blue.
The brown color of the color indicates the destruction of the drying properties as a result of overheating.
Drying agent can be regenerated up to 50 times
8.4 Assemble the air dryer. The oil seal must be transparent.
Fill the air dryer space with a mixture of 80% silica gel (white) and 20% blaugel (bright blue).
8.5.Install the air dryer on the expansion tank and fill the oil seal of the air dryer with transformer oil up to the level indicated by the mark on the oil seal.
Repair of gas relay BF50/10/
9.1. To remove the relay from the transformer, after draining the oil from the transformer, unscrew the outlet bolt in the lower part of the relay housing and drain the oil, disconnect the control circuit wires from the terminal rail, disconnect the grounding shunt and remove the relay.
9.2 Remove the internal mechanism from the housing, carefully inspect, eliminate defects, assemble the relay.
9.3 Test the dielectric strength of the insulation of the electrical circuits of the relay relative to the housing with and without transformer oil.
The test is carried out with an alternating voltage of 2.5 kV with a frequency of 50 Hz for 5 seconds.
9.4 Check the relay for tightness.
The check should be carried out within 20 min. With an excess oil pressure of 1 kgf / cm 2, there should not be a drop in oil pressure, observed on the stand pressure gauge, and there should be no oil leakage from the relay.
9.5 Carry out a functional test of the relay.
9.5.1 Carry out a triple control of the operation using the control button on the relay filled with oil.
In this case, the signal lamp of the stand should work.
9.5.2 Check the operation of the relay when the oil level drops.
Inflate air through the control cock. In this case, the signal lamp of the stand should work.
Drain the oil from the relay. In this case, two signal lamps of the stand should work.
9.6 Test results according to paragraphs 9.3.-9.5. put in a journal.
9.7 Put a working relay on the transformer and connect the wires of the control circuits to the terminal rail in accordance with the diagram.
Testing thermostats.
10.1 Install the thermostat in a bath with transformer oil heated to 60-80 0 C and a control thermometer placed in it.
10.2 Set the thermostat to the maximum temperature (110 0 C).
10.3 Connect to terminals 1,3 of the thermostat the electrical circuit for signaling the thermostat on.
10.4. Gradually reduce the temperature of the thermostat setpoint until the alarm is triggered to turn on the thermostat.
10.5. Compare the readings of the control thermometer with the readings of the thermostat scale.
10.6. If the readings of the thermostat and the control thermometer coincide, install the thermostat on the transformer tank.
10.7 If the readings do not match, adjust the thermostat.
Use a screwdriver to fix the adjusting axle. Loosen the set screw. While holding the axis, set the scale with the mark to the actual temperature at which the thermostat should have worked. Fasten the set screw.
10.8 After adjustment, test the thermostat again according to paragraphs 10.1.-10.5.
10.9 Connect the wires of the control circuits to the terminals of the thermostats according to the wiring diagram.
10.10 Adjust thermostat settings:
01513 - setting 80 0 С;
01525 - setting 40 0 С;
01526 - setting 60 0 С;
01529 - setting 20 0 С.
Traction transformer tests.
Transformer testing after SR.
Transformer tests after TR-3.
11.1 Preparatory operations.
11.1.1 Ground the transformer case.
11.1.2 Turn on the oil pumps and pump oil for 2 hours.
Settle the oil for 12 hours.
11.1.3 Perform an oil analysis in accordance with the Instructions for the use of lubricants on locomotives and MVPS TsT-2635.
11.1.4 Release air from insulators, radiators, gas relay, voltage switch.
11.1.5 Check the operation of the PS oil filtration pump, PS oil heating system.
11.1.6 Check the polarity of the switching on of the current transformers protecting the high voltage winding and the correctness of the circuit in the terminal box. Ring current transformers of traction windings and heating windings.
11.1.7 Short-circuit and ground all current transformers.
11.2.1 Measure the insulation resistance of all windings relative to the housing and relative to each other with a 2500 V megger.
The insulation resistance must be at least:
- high-voltage winding - 100 MΩ;
- heating winding - 10 MΩ;
- traction windings - 20 MΩ;
- winding of own needs - 5 MΩ.
Determine the absorption coefficient (moisture content of the windings)
K \u003d R60 / R15\u003e 1,
At a measurement temperature above 15 0 C, recalculate by multiplying the readings by a coefficient from the table
| temperature difference | 5 0 С | 10 0 С | 15 0 C | 20 0 С | 25 0 С | 30 0 С |
| Coefficient | 1,23 | 1,5 | 1,64 | 2,25 | 2,75 | 3,4 |
11.2.2 Measure the ohmic resistance of the windings using a voltmeter-ammeter or a DC bridge.
Check the resistance of the autotransformer winding at all positions.
The resistance values should not differ from the nominal ones by more than 10%.
Nominal values of winding resistance, MOhm
| m1-m2 | m3-m4 | E-J | E-H | E-G | E-F | C1-C2 | Do-D25 | Do-D1 |
| 1,6 | 1,6 | 1,1 | 0,8 | 0,66 | 0,42 | 46 | 492 | 460 |
Autotransformer winding resistance by position, mΩ
| Pos. | Resist. | Pos. | Resist. | Pos. | Resist. | Pos. | Resist. |
| Do-1 | 19,2 | Do-9 | 98,4 | Do-17 | 210,0 | Do-25 | 364,0 |
Resistance of coils of autotransformer winding, Ohm
| Cat. | Resist. | Cat. | Resist. | Cat. | Resist. | Cat. | Resist. |
| 1 | 0,0182 | 4 | 0,0080 | 7 | 0,0086 | 10 | 0,0104 |
At an ambient temperature that differs from 15 0 C, it is necessary to bring the resistance to 15 0 C according to the formula:
R 15 \u003d R env - , where
R okr - winding resistance at ambient temperature
environment, Ohm;
t env - ambient temperature, 0 С.
11.2.3 Checking the transformation ratio.
Apply to the high voltage winding by placing a jumper Do-PS, voltage 200 V.
Measure voltages at all positions of the autotransformer winding and at all other windings with the PS position at 32 pos.
Voltage values must correspond to those indicated in the table
| conclusions | Do-D | m1-m2 | m3-m4 | C1-C2 | E-F | E-G | E-H | E-J |
| Voltage, V | 200 | 8,3 | 8,3 | 24,7 | 1,1 | 1,8 | 2,1 | 2,8 |
| NN | For example, in | NN | For example, in | NN | For example, in | NN | For example, in |
| 1 | 7,4 | 9 | 42,8 | 17 | 82,3 | 25 | 142,8 |
11.2.4 Testing the dielectric strength of the winding insulation relative to each other and relative to the housing with a voltage of 50 Hz for 1 min.
Test voltage values:
- HV winding 25 kV (Do, D1, D25) - 52.5 kV;
- heating winding (C1, C2) - 11.2 kV;
- traction windings (m1-m2, m3-m4) - 4.9 kV;
- auxiliary winding (E-J) - 1.54 kV.
The test voltage is applied between the short-circuited winding to be tested and the earthed tank to which all other short-circuited transformer windings are connected.
The transformer is considered to have passed the test if no breakdown or partial discharges were observed during the tests, determined by sound, gas, smoke or instrument readings.
11.2.5 Test of dielectric strength of insulation by induced voltage with double rated voltage of increased frequency of 200 Hz for 30 sec. The test checks the turn insulation of the transformer windings.
A voltage of 2080 V is applied to the terminals m3-m4 of the traction winding, the remaining windings are open, while one output of each winding (Do, E, C1, m1) is grounded.
The transformer is considered to have passed the test, if during the tests there were no current surges, no smoke from the expander.
11.2.6 Idling experience.
Measure losses and no-load current, while checking the condition of the magnetic system of the transformer. Connect the rated voltage to the m3-m4 winding, and then 115% of the rated voltage with a frequency of 50 Hz. All
the remaining windings are open, one terminal of each winding is grounded.
The following values of losses and current x.x are allowed.
Uxx=1040 V Ixx=90-120 A Pxx=94-125 kW
Uxx=1200 V Ixx=100-140 A Pxx=120-168 kW
11.2.7 Short circuit test.
Apply a voltage of 200 V with a frequency of 50 Hz to the Do-D25 winding. windings low voltage are short-circuited in turn, the current, voltage and short-circuit power are measured.
Measured short-circuit losses convert to nominal values:
Рн=Рism*K1*K2, where
Rism — measured short-circuit losses, kW;
К1=Uн/Umeas — voltage conversion factor;
К2=In/Imeas — current conversion factor.
By comparing the measured values, reduced to the nominal mode, with the permissible ones, check the correctness of the windings.
When shorting the traction windings, simultaneously check the current transformers protecting the traction windings. When short-circuiting the heating winding, check the current transformers protecting the heating winding.
| Shorted pins | Transformer terminals | K=Iobm/Itransf |
| m1-m2 | 836-837 | 80 |
11.2.8 Check the insulation resistance of all windings as in paragraph 11.2.1.
11.3.1 Measurement of winding insulation resistance according to clause 11.2.1.
11.3.2 Measurement of the ohmic resistance of the windings according to clause 11.2.2.
11.3.3 Testing the electrical strength of the winding insulation according to clause 11.2.4.
11.3.4 Idling test according to item 11.2.6.
Coloring of external surfaces of the transformer.
12.1 Paint the cooling system with PF-115 enamel yellow color at least 2 times.
12.2 Paint the transformer with PF-115 enamel gray color at least 2 times.
12.3 Paint the underbody part of the transformer with black enamel.
Delivery of the transformer to the receiver of locomotives.
13.1 Fill in the transformer test report.
13.2 Together with the workshop foreman, present the transformer for delivery to the locomotive receiver.
Maintenance transformers with a capacity of 10000 - 63000 kV-A 1. The composition of the performers
Electromechanic - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
Preparatory work and permission to work
4.1. On the eve of the work, apply for the withdrawal of the trans for repair
formatter.
4.2. Check the serviceability and expiration dates of protective equipment, devices
ditch, prepare tools, mounting fixtures and materials.
4.3. After issuing an order to the work foreman, receive instructions from
the person who issued the order.
4.4. Operational personnel to prepare the workplace.
For the foreman to check the implementation of technical measures for
workplace preparation.
4.5. Get the team to work.
4.6. The foreman to instruct the members of the brigade and clearly
distribute responsibilities among them.
End of technological card No. 2.2.
| Oil change in hydraulic seals of oil-filled bushings a silica gel in moisture-absorbing cartridges (see fig. 2.1.1 ., fig. 2. 1 .3.) | The condition of the silica gel in the desiccant cartridges is determined by the color of the indicator silica gel. If the color changes from blue to pink, replace the silica gel in the cartridges and the oil in the water seal. Replace Siliga gel in dry weather, taking the dryer out of operation for no more than one hour. Check the oil level in the hydraulic seal. The replacement of silica gel is carried out as follows: disconnect the cartridge from the input, replace the silica gel, having previously cleaned the cartridge of contamination, change the oil in the hydraulic seal, attach the cartridge to the input | |
| Checking the working condition of the cranes and dampers of the transformer | Check the compliance with the working position of devices, valves, dampers. Carry out an inspection with checking the oil level in the bushings and tanks of the transformer. Record readings of thermal alarms, oil level indicators, air temperature, position of switches of all windings |
Note. All operations with oil filled and 110-220 kV bushings must be carried out in cooperation with a RRU specialist.
Completion of works
Technological map No. 2.3. Current repair of autotransformers for voltage 110-220 kV
Cast
Electromechanic - 1
Traction substation electrician 4th category - 1
Traction substation electrician 3rd category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Safety helmets, safety belt, ladder, grounding, shorts, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, stopwatch, thermometer, level, pump with pressure gauge and hose, wrenches, combination pliers, screwdrivers, scraper, brushes, container for draining sediment, glass containers with a ground stopper for oil sampling, indicator silica gel, silica gel, transformer oil, TsIA-TIM lubricant, white spirit, moisture-oil-resistant varnish or enamel, spare oil-indicating glasses, rubber gaskets, cleaning material, rag
Technological map No. 2.4. Current repair of transformers with a capacity of 40 - 630 kV-A
Cast
Electromechanic - 1
Traction substation electrician 3rd category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Safety helmets, safety belt, ladder, grounding, shorts, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, stopwatch, thermometer, level, pump with pressure gauge and hose, wrenches, combination pliers, screwdrivers, scraper, brushes, container for draining sediment, glass containers with a ground stopper for oil sampling, indicator silica gel, silica gel, zeolite, transformer oil, CIATIM lubricant, white spirit, moisture-oil-resistant varnish or enamel, spare oil-indicating glasses, rubber gaskets, cleaning material, rag
Oil circuit breakers
Continuation of technological map No. 3.1.
Cast
Electromechanic - 1
Traction substation electrician 4 categories - 1 Traction substation electrician 3 categories - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Safety helmets, safety belt, ladder, grounding, short circuits, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, electric stopwatch, wrenches, combined pliers, screwdrivers, scraper, brushes, glass containers with a ground stopper for oil sampling, silica gel indicator, silica gel, transformer oil, CIATIM grease, white spirit, insulating varnish, spare oil-indicating glasses, rubber gaskets, cleaning material, rags
Cast
Electromechanic - 1
Traction substation electrician 3rd category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Protective helmets, safety belt, ladder, grounding, short circuits, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, LVI-100 test facility, electric stopwatch, wrenches, combined pliers, screwdrivers, scraper, brushes, transformer oil, CIATIM lubricant, white spirit, insulating varnish, spare oil-indicating glasses, rubber gaskets, cleaning material, rags
Completion of works
6.1. Collect instruments, tools, fixtures and materials.
6.2. Return to the switchboard traction substation.
6.3. Pass workplace admitting and close the outfit
6.4. Record the results of the measurements taken in a protocol.
Cast
Electromechanic - 1
Traction substation electrician 3rd category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Protective helmets, grounding, short circuits, dielectric gloves, megohmmeter for voltage 1000 and 2500 V, electric stopwatch, wrenches, combination pliers, screwdrivers, scraper, transformer oil, TsIA-TIM grease, white spirit, insulating varnish, spare oil-indicating glasses, rubber pads, cleaning material, rags
Completion of works
6.1. Collect instruments, tools, fixtures and materials.
6.2. Return to the switchboard traction substation.
6.3. Hand over the workplace to the admitting and close the outfit
6.4. Record the results of the measurements taken in a protocol.
Cast
Electromechanic - 1
Traction substation electrician 4th category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Megaohmmeter for voltage 500 and 2500 V, tester, electric soldering iron, vacuum cleaner, calibration wrench, spanners, combined pliers, screwdrivers, files, scraper, control lamp, hair brush, wooden ladder, ladder, white spirit, cleaning material, CIATIM lubricant
Completion of works
6.1. Collect instruments, tools, fixtures and materials.
6.2. Return to the switchboard traction substation.
6.3. Hand over the workplace to the admitting and close the outfit
6.4. Record the results of the measurements taken in a protocol.
Cast
Electromechanic - 1
Traction substation electrician 4th category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Ohmmeter, portable lamp, vacuum cleaner, wrenches and socket wrenches, screwdrivers, ruler, caliper, files, scraper, wire brush, set of probes, files for cleaning switch contacts, wooden stick, sandpaper, white and carbon paper, white spirit, lubricant CIATIM, rags, cleaning material
Cast
Electromechanic - 1
Traction substation electrician 4th category - 1
Terms of work
The work is being done:
2.1. With stress relief
2.2. Alongside
3. Protective equipment, devices, tools, fixtures and materials:
Stopwatch, portable lamp, vacuum cleaner, wrenches and socket wrenches, screwdrivers, ruler, caliper, files, scraper, wire brush, set of probes, files for cleaning switch contacts, glass cloth, wooden stick, sandpaper, white and carbon paper, white spirit, TsIA-TIM lubricant, rags, cleaning material
Transformers Technological map No. 2.1.
