The insulating oil in the power transformer needs to be checked regularly after long-term use to judge the insulation withstand voltage level of the transformer oil and whether it can be used. Therefore, there is a need for an insulating oil dielectric strength tester. After the equipment tests the insulating oil, how to judge the test results is particularly important. If the results cannot be judged, then the test is meaningless. This article will briefly introduce how to judge the test results of insulating oil withstand voltage tester (also called oil dielectric strength tester).
In the test, the discharge resistance of insulating oil has four changes:
1. The spark discharge voltage is extremely low. There may be some external factors in this test, because the oil sample is injected into the surface of the oil cup or the electrode of the oil cup before the injection, which makes the value of this test deviate, a little lower, at this point, it can be taken 2-6 times on average.
2.6 The spark discharge voltage value gradually increases, which usually occurs in oil samples that are not thoroughly cleaned or treated and have hygroscopicity, which is due to the increase in oil humidity after spark discharge.
3. The value of the six spark discharge voltages gradually decreases, which usually occurs in the pure oil test, because the free charged particles, air bubbles and carbon chips increase one by one, destroying the insulating properties of the oil, and the automatic oil test, in continuous There was no stirring in all six tests, and the carbon particles between the electrodes gradually increased, resulting in a decrease in the spark discharge voltage.
4. The spark discharge voltage is low at both ends and high in the middle, which is a normal phenomenon.
