Influence of Transformer Capacity on Insulator Leakage Current Acquisition Results

Abstract

To study the influence of test transformer capacity on insulator leakage current acquisition results, leakage current acquisition experiments with the clean and dry insulator and the water drops attached insulator were conducted based on the sampling resistor method and the test transformers of different capacities whose models are YDTW-1200 kVA/300 kV, YDTW-50 kVA/250 kV, YDTW-10 kVA/100 kV, YDJ-5 kVA/50 kV respectively. To make the results more reliable, sampling resistors with different resistances, 10 Ω, 100 Ω, and 1 kΩ, were used to collect the leakage current. The root-mean-square (RMS) values of the leakage current, the ratio of the 3rd harmonic to the fundamental (K3) and the 5th harmonic to the fundamental (K5) were extracted from the measured data. And it was discovered that the transformer capacities has a very slight influence on the leakage current RMS value but has a great impact on the value of K3 and the K5. The maximum K3 are approximately 3 times of the minimum K3 and the maximum K5 are approximately 9 times of the minimum K5.