Study on the relationship between off-line PD and on-line PD of power transformers

The contrastive analytical research is proceeded to off-line partial discharge and on-line partial discharge of power transformer in aspects of internal electric-field distribution, partial discharge signal extraction method, pattern-recognition method and anti-interference measure. 2D finite element model is adopted to emulator calculating for the internal electric-field of power transformer test condition and operating condition. Time harmonic electric-field solution method is adopted to simulate the frequency differences in test procedure and operational state. The relationship between off-line partial discharge and on-line partial discharge of power transformer is analytically inducted systematically and completely.