Daily Maintenance Procedures of Isolation Transformer
1. The normal operation of isolation transformer is the fundamental guarantee for the safe and reliable power supply of power grid. Therefore, the daily maintenance of transformers is very necessary. This paper introduces the maintenance methods and fault treatment measures of isolation transformer, which has great practical value for safe and stable operation of power grid. Whether the sound is normal or not, there is a uniform buzz in normal operation. The upper oil temperature should not exceed 85 degrees C. Are there any oil leakage phenomena, oil color and oil level indicators normal?
2. Whether the casing is clean or not, whether there are damages, cracks, discharge traces and other phenomena 5. No rupture of explosion-proof tube film, no oil leakage. 6. Whether the oil level in the window of the gas relay of the Isolation Transformer is normal and whether there is gas or not.
8. Permissible Operation Mode of Transformers
1. In the operation of isolation transformer, the upper oil temperature should not exceed 85 C, and the maximum should not exceed 95 C.
2. The voltage added to the voltage tap of the isolation transformer shall not exceed 5% of the rated value.
3. Transformers can operate under normal overload conditions, and normal overload can be used frequently. Its allowable value is determined by the transformer's load curve, the temperature of cooling medium and the load of transformer before overload by the technical personnel in charge of the unit. In case of accident, it is allowed to run for two hours under 30 overload, but the upper oil temperature of isolation transformer shall not exceed 85 C. During the maintenance of transformer, it is necessary to check whether the grounding of transformer is good, whether the ground wire is rotten or not, and if the decomposition is serious, it should be replaced; tighten the lead terminal, pin, grounding screw and connecting busbar screw; clean the dust around the transformer and its accessories, check whether the fire fighting facilities and ventilation system are good or not, whether there are problems with the cooling fan, whether the temperature controller is bad or not, break off. Turn on the grounding switch on the high-voltage side and lock the high-voltage switch bars. Measure the insulation resistance with 2500V shake table. Compared with the measured value before the transformer leaves the factory, the insulation resistance should not be lower than 70% of the original data at the time of leaving the factory. If it does not meet the standard, it should be immediately reported for disposal. Once again, close the grounding switch on the high-voltage side, let the transformer discharge, check whether the transformer chamber and transformer have left-over tools, and evacuate the site. Personnel should make detailed records of transformer maintenance and trial operation so as to be prepared for positive maintenance in the future.