How to measure the insulation resistance of transformer?
The transformer insulation is divided into "(high pressure) to low (high pressure), (pressure) on the ground, low (pressure) on the three case", such as the discovery of transformer insulation resistance differences should be used in shielding test (high and low pressure side pile caps for short wire connected to the shielding pile head shaking table on the use of the method of shielding), should pay attention to the live parts of shielding line, should keep the hand to live parts of the safe distance. If the transformer insulation resistance increases after testing, it shows that the transformer internal and high and low pressure bushing parts may have been damp, the transformer needs drying treatment.
Before the test, all the pile heads of the high and low voltage side of the transformer should be fully discharged, and the residual charge inside the transformer (transformer belongs to the capacitive type electrical equipment) can be tested. When testing, the insulation shaking table should be placed in the horizontal position, holding the insulation part of the insulation shaking table. The watch pointer will rise slowly with the shaking. When it reaches infinity, it will be short connected to the two terminals: L and E. You will find the pointer "O"". Can continue to use the shake table to test the insulation resistance.
To measure the insulation resistance of transformers, for the power transformers with voltage class 10kV, we usually use the 2500V ohmmeter (commonly known as the shake table).
