Sharif Digital Repository

Measurement of partial discharges (PDs) current pulses is found to be one of the most efficient methods to evaluate the high voltage electrical equipment insulation condition. Generators, transformers, cables and transmission lines are especially tested for the presence of PDs. In AC, the solution is well known. Phase-resolved method can be used to detect and determine partial discharge activities. Although phase-resolved method works well under AC voltage; due to lack of a cyclic variation in DC voltage and current this cannot be used when studying partial discharges in DC voltage systems. Therefore, other methods are employed to interpret the partial discharge in DC. For this purpose, the... 

Partial discharge (PD) activity can be destructive to the transformer insulation, and ultimately may result in total breakdown of the insulation. Partial discharge sources identification in a power transformer enables the operator to evaluate the transformer insulation condition during its lifetime. In order to identify the PD source; in the case of presence of multiple sources; the first step is to capture the PD signals and to extract their specific features. In this contribution, the frequency domain analysis, the time domain analysis and the wavelet transform are employed for feature extraction purpose. In practice, there might be plenty of features, and in each scenario, only some of...