Partial Discharge Analysis and Simulation Using the Consecutive Pulses Correlation Method

Ondřej Kozák,Josef Pihera

doi:10.3390/en14092567

Abstract

The behaviour of partial discharge as consequences of an alternating current (AC) is already well defined. AC partial discharges have completely different behaviour, background physics and parameters than partial discharges (PD) under direct current (DC) stress. This paper focuses on the most used and promising evaluation method of the PD DC stress—pulse sequence analysis (PSA). The first step is understanding and verifying the mechanisms and principles of this method. It is provided by well-known fundamentals of AC PD and by comparison with the other diagnostic and fault-locating methods such as phase-resolved partial discharge (PRPD) and pulse diagrams. The paper shows the PSA simulations and PD analyses performed at AC and partly at DC test conditions on typical PD test arrangements such as corona, surface and internal discharges. It is shown that the simulations performed, compared and validated with data obtained from measurements on different PD arrangements are a good match. This fact opens the way for the PD source recognition in DC, especially the time-resolved pulse sequence analysis described in detail in the paper.

Highlights

Partial discharge (PD) detection and evaluation is an important tool for electrical insulation systems diagnosis and quality measures
The absence of the phase is the major issue for distinguishing a direct current (DC) PD source
Alternating current (AC) partial discharges were used as the first step of Q-t pulse sequence analysis (PSA) verification for DC conditions

Summary

Introduction

Partial discharge (PD) detection and evaluation is an important tool for electrical insulation systems diagnosis and quality measures. Alternating current (AC) PD measurements have well described diagnostic tools which cannot be applied for DC voltage For this reason, evaluation processes, procedures and methods should be developed for DC conditions. PD under DC voltage has the same physical effects as PD under AC voltage, methods or procedures for DC PD evaluation compared to the AC standard EIC 60270 (i.e., phase-resolved partial discharges (PRPD) analysis) are missing. PRPD analysis is the most used AC partial discharge activity evaluation method This method uses the phase of the pulse occurrence and apparent charge of the pulse for PD source recognition. The most frequently acquired values are apparent charge Q, time t (or period and phase) and voltage U of pulse occurrence for AC measurement.

Results and Discussion

Surface Discharges

Conclusions