Common troubleshooting methods for oil-immersed transformers

There are all kinds of failures of oil-immersed transformers, and the causes of oil-immersed transformer failures may be:

Poor assembly with mechanical equipment;

Prolonged operation with high loads;

Power supply out of phase, voltage or frequency mismatch;

Short-circuiting, disconnection or grounding of the windings, poor operation of the bearings;

Internal and external long time without cleaning, operating environment is dirty or ambient temperature is too high and so on.

Oil-immersed transformer components may have a greater likelihood of failure, from which we can know in-depth understanding of the composition of the oil-immersed transformer and the principle of operation, can help us in the oil-immersed transformer overhaul and maintenance to give a great deal of help.

The normal work of oil-immersed transformer and the surrounding environment has a great relationship. Therefore, the daily inspection process, see the oil-immersed transformer around the leakage, water dripping situation (will cause the oil-immersed transformer insulation low and cause breakdown so that burned), see the oil-immersed transformer periphery whether there is an impact on the ventilation and cooling environment of the object to avoid the indispensable, at the same time, regular monitoring of the oil-immersed transformer working current and change is also very important.

In order to ensure that the effect of oil-immersed transformer cooling, high frequency regular treatment of oil-immersed transformer external ﹑ fan end cover and fan blade dirt although it seems to play a small role, in fact, it accounted for the proportion of routine maintenance of oil-immersed transformer is very large.

Probe the temperature around the oil-immersed transformer with the back of the hand, if the overall temperature of the oil-immersed transformer is higher than the normal operating temperature, it is necessary to check the oil-immersed transformer combined with the oil-immersed transformer operating current to the oil-immersed transformer loads ﹑ assembly and ventilation to deal with the situation, and in the sister sister bearer in good condition, the temperature of the two ends of the general temperature is lower than that of the intermediate winding section.

In the oil-immersed transformer stops working, to regularly (good is every month) with the insulation meter to measure the oil-immersed transformer between the phases or relative to the ground insulation resistance, through and the results of the last month's test compared with the timely discovery of insulation defects. Oil-immersed transformer, for example, the measured resistance of the unevenness can not exceed 2%, and insulation resistance check, such as less than 5MΩ, it is necessary to analyse the reasons for this abnormal situation. Check whether the insulation is damp, or due to the winding of the insulation is not good caused by the grounding of the situation and so on. If detected by the bridge test, resistance equalisation and no more obvious problems, it is purely insulation moisture, then drying treatment, re-run Xuzhou oil-immersed transformer to see whether the situation is back to normal, if the stator resistance is not balanced, the oil-immersed transformer coils were done to the ground voltage withstand test and turn-to-turn experiments have been to find out the grounding point. With moisture baking electric heating oil-immersed transformer unless special circumstances, do not arbitrarily switch off the heating switch. If the oil-immersed transformer is found to be immersed in water, the oil-immersed transformer should be disassembled and extracted from the rotor, and then blow-dry with compressed air, but also with a baking lamp from the oil-immersed transformer stator within the two ends of the baking, until the oil-immersed transformer insulation is normal.