Installation steps of single-phase on-load transformer of 24000kVA transformer 1000 min

1 installation steps and technical requirements 1. 1 prepare construction machinery and tool materials in the preparation stage. When moving the transformer, no matter by hand or by rope, you should not focus on the oil pipe to prevent the oil leakage caused by the rupture of the weld of the oil pipe. When moving, the transformer should also be prevented from toppling, and the transformer foundation or track should be horizontal. 1.2 insulation inspection After the power transformer is in place, a comprehensive insulation inspection should be carried out before hanging the cover to check the iron core, so as to know whether the transformer in the transportation state is damp after leaving the factory, so as to determine the next installation steps and methods. The steps and methods of insulation inspection are as follows: 1.2. 1 Take an oil sample to detect the insulation oil of power transformer, and simplify the analysis into seven items: flash point and flash point. Old and new engine oils should be sampled and tested with mixed engine oils. 1.2.2 Inspection of oil tank tightness First, visually check whether there is oil leakage at all welds and seals, and whether the transformer seal is in good condition during transportation. 1.2.3 coil insulation measurement and insulation judgment 1) Measure the insulation resistance R60s value and absorption ratio R60s value of each phase /R 15s. 2) Measure the tangent of each phase dielectric loss. 1.2.4 insulation judgment According to the insulation inspection results and the situation that the national standard power transformer is put into operation without drying, if the insulation is qualified, the hanging cover inspection and final assembly can be carried out; If it is unqualified, it is necessary to dry the insulation first. This judgment should be taken seriously. 2. Inspection of hanging hood and oil filtering and oiling 2. 1 Requirements on environment, climate and time 2. 1. 1 Transformer should be inspected with hanging hood outdoors, and there should be effective methods to prevent rain and dust. Canvas tents should be built around the transformer to prevent wind and dust, and plastic sheets should be prepared on the ceiling to prevent showers. 2. 1.2 The contact time between the transformer body and the air from oil discharge to oil filling shall not exceed the following provisions:16h in dry weather when the air relative humidity does not exceed 65%; Wet weather with air relative humidity not exceeding 75%:12h; When the relative humidity of air exceeds 75%, the core hanging inspection shall not be carried out. You should master the weather forecast, hang a hood on sunny days, and it is forbidden to do it on rainy and foggy days. 2. 1.3 The body temperature should be higher than the ambient air temperature, otherwise the heater body should be heated first. 2.2 Preparation before lifting the cover 2.2. 1 In order to prevent the insulation of the iron core from being damaged in the process of lifting the cover, the electrolyte generated by the water around the transformer will corrode the pipeline, so pay attention to its water absorption when selecting the insulation material. 2) A safe and reliable waterproof layer should be added outside the pipeline insulation layer to prevent water vapor in the environment from infiltrating into the insulation layer and causing metal corrosion. 3) When the pipe network is laid in the ditch, it must be kept dry, and the ditch should be provided with necessary drainage facilities and ventilated regularly to reduce the water content in the ditch. 4) Increase the temperature of the heating medium. When the pipeline is heated by medium to above 100℃, the moisture in the insulation layer will be discharged into the air to reduce heat loss and pipeline corrosion. However, after the temperature of the medium rises, the internal corrosion of the pipe network will increase in a certain range, so before the temperature rises, economic analysis should be carried out to determine the optimal temperature of the medium. 2.2 Anti-corrosion measures inside the heating pipe network 1) Reduce the concentration of dissolved oxygen in water and reach the water quality standard. From the previous analysis, it can be seen that oxygen corrosion is the main cause of pipe network corrosion, so the oxygen removal system must be put into operation effectively. 2) Ensure that the pH value of water in the pipe network is within the specified range. 3) Control the water temperature to avoid the largest corrosion area. 4) Reduce the water loss rate of the system, thereby reducing the water supply of the system and reducing the corrosion caused by the water quality. 5) During the period when the heating pipe network stops heating, wet curing should be adopted. After the heating is stopped, the circulating water filled with impurities and turbidity in the system is released, and softened water for chemical treatment and deoxygenation is supplemented, and then the system is stopped for maintenance. If conditions permit, corrosion inhibitors, such as HL9 1 1 and HL9 12, can be added to the water to achieve better anticorrosion effect.

Four straight poles are embedded in the edge to control the vertical inclination when landing. 2.2.2 In order to facilitate the inspection of the iron core, a circle of work frame should be built around the transformer iron core at an appropriate height, and the work frame should be covered with wooden boards and must be firm. 2.2.3 Before hanging the cover of the transformer, all insulating oil should be pumped out and put into the closed oil tank. The oil in the transformer will be transferred, which will inevitably bring in impurities and moisture to reduce the pressure of insulating oil. Therefore, when checking the hanging cover, the oil discharged from the transformer should be filtered twice. 2.2.4 When operating the transformer suspension cover, apart from removing transformer oil, it is also necessary to loosen the nuts of the upper positioning piece and the high-voltage outlet terminal, open the observation window of the low-voltage lifting seat, remove the connecting bolt for switching the low-voltage lug, remove the operating mechanism of the tap changer, remove the operating cover at the tap changer, and remove the tap lead and other connectors before hanging the cover. When lifting the hood, if it is difficult to separate the next fuel tank, pry the edge of the fuel tank with a crowbar, and do not lift it forcibly. Tap-changer and its parts removed from the hanging hood shall be marked and numbered, wrapped with clean plastic cloth, and reassembled after inspection. 3. Contents of hanging core detector body 3. 1 Check whether the fastening bolts of various parts of the detector body are loose, and tighten them if found loose. 3.2 Whether the wire clamping is loose and the connector is in good condition. 3.3 Insulation is damaged and the gasket is loose. 3.4 Check the insulation resistance of the coil and make records. 3.5 Check the insulation between the iron core and the ground, and the iron core should be grounded at multiple points. 3.6 Check the DC resistance of the coil at each position of the switch to determine whether the contact of the switch is good and whether the tap position is consistent with the indicated value. 3.7 After inspection, the machine body shall be cleaned, and there shall be no sundries on the machine body and in the fuel tank. 3.8 The operating mechanism of transformer tap-changer without excitation must be installed according to the sign before hanging the core, and the operating rod should be prevented from being inserted outside the switch locating pin, so as to avoid misoperation during closing and tapping. For the transformer whose iron core leads out of the oil tank and is grounded externally, the original loose upper positioning piece (transport sleeve) does not need to be reinstalled after inspection, but it is tightly sealed, and it is necessary to ensure that the upper clamping piece of the iron core does not contact with the oil tank. 3.9 After the inspection of the body, before installing the fuel tank, flush the body with qualified net insulating oil to remove +9.438+0 impurities between coils. 3. 10 The following electrical parameters should be measured when checking the machine body: 1) Insulation resistance between the iron core and the clamp (if the clamp has a grounding piece connected to the iron core, it should be removed). 2) Iron core grounding and metal clip grounding. 3) Measure the insulation resistance of the through bolt, iron core, oil tank and coil pressure ring with a 2500V megohmmeter. 3. 1 1 Properly handle the faults and defects found in the body inspection, and keep records of the handling for future reference. 3. 12 When reassembling the fuel tank in the previous section, first scrub the vicinity of the fuel tank cover, check that the large sealing ring is free of damage and dirt adhesion, and then reassemble according to the reverse steps in the hanging cover to prevent the coil insulation from being damaged. Accessories shall be installed in the order of cooler, oil purifier, oil reservoir, moisture absorber, signal thermometer and platinum resistor of gas relay. 4. 1 Install the cooler 4. 1. 1 Before installation, check whether the weld between the cooler and the oil collecting tank and the weld of the fan bracket leaks oil. 4. 1.2 Wash the inside of the cooler with qualified thermal insulating oil, and the oil will flow out from the upper nozzle and enter the lower nozzle. Until the oil taken out from the bottom nozzle passes the inspection, it can be considered that the inside of the cooler is cleaned and can be installed. 4. 1.3 When the lifting oil cooler meets the flange on the transformer oil tank, the error of the upper and lower headers should be adjusted to the minimum, and the oil-resistant rubber sealing ring should be flat and the pressing area should be appropriate. 4. 1.4 Before installing the fan, check whether the motor and impeller are damaged, whether the shaft end and impeller blades are bent, whether the rotation is flexible, and whether there are noises such as rubbing and bumping. 4.2 Installation of oil purifier 4.2. 1 Before installation, open all parts of the oil purifier and clean them, rinse them with dry and clean transformer oil for several times, then assemble the transformer and put it into silica gel with a particle size of 2mm~7mm. Pay attention to the packaging of silica gel when using it, and wash it with dry and clean transformer oil before loading it. Silica gel should be washed after drying and then loaded. 4.2.2 The oil filling method of the oil purifier is to slightly open the lower valve, so that the transformer oil flows in, and at the same time, the oil is deflated from the upper part of the oil purifier until the oil overflows. Then close the lower valve, let the oil purifier stand 1 1h, and then open the lower oil drain plug to discharge the sediment. After treatment, inject oil according to the above method, and then open the upper valve. Finally, replenish the oil in the transformer main oil tank to the specified height. 4.3 Installation of diaphragm oil storage tank 4.3. 1 Wash the oil storage tank with qualified transformer oil first, and check the sealing condition and diaphragm bag for leakage or rupture, and carefully check the oil pressure bag mouth and pipeline joint. Test the whole diaphragm bag with air pressure not greater than 0.0002MPa, and pay attention to whether the length direction of the diaphragm bag after being put into the oil storage tank is consistent with the long axis direction of the oil storage tank, so as to prevent the bag mouth from being twisted or wrinkled. 4.3.2 After the oil storage tank is installed on the transformer, its accessories: oil gauge, oil pressure bag, diaphragm bag, moisture absorber, pipeline, etc. should be connected before oil filling. The dehumidifier should be inspected in advance and filled with dry and clean silica gel. 4.3.3 Before filling the oil tank, it must be filled with oil, then drained through the lower header of the oil tank, and then drained to the normal oil level through the drain hole of the oil gauge. At this point, the diaphragm bag in the oil tank automatically inflates with the oil gauge and floats on the oil level normally, so that the oil tank can be put into operation with the transformer. 5 Preparation before commissioning 1) The grounding point of the small casing led from the oil tank shell and iron core is reliably grounded. 2) The dehumidifier system has been unblocked. 3) The throttle valve of the cooler is fully opened. 4) The throttle of the oil storage tank and the connecting pipe of the transformer has been turned on, and the oil level of the oil storage tank is appropriate. 5) There is no oil leakage around the transformer. 6) The gas relay should be deflated first, and the transmission test is normal. 7) Inject a proper amount of clean transformer oil into the resistance thermometer bracket.