Pulse sequence studies on PD data

Partial discharge (PD) pulses are measured to assess the condition of the insulation under test. The pulse magnitude and its phase position are the most commonly measured parameters. The PD pulse magnitude is used as an index to the quality of the insulation under test. The phase information is used to identify the type of PD. The most common method of PD analysis is statistical analysis on PD distributions. The representation of PD data as distributions all though convenient for representation of magnitude variations, loses the PD pulse sequence information. Recent studies have shown that PD pulse sequence contains information useful for understanding of PD phenomena. The paper presents pulse sequence studies with PD data obtained from model insulation systems representing different types of discharge models. The study brings out different characteristics of discharges and their variations with the applied voltage. The paper discusses the changes in the charge magnitude, the time between pulses and their relation with the phase of occurrence of PD. The use of time information for simple measurement and recognition of PD is also discussed.