The design and application of a novel high-speed partial discharge diagnostic system

A high-speed partial discharge diagnostic system that can monitor transient and fast-risetime (on the order of several-nanosecond) partial discharge pulses in capacitor insulation with good sensitivity and fidelity has been developed. This system is referred to as the fast discharge detector (FDD). The key performance specifications include a detection sensitivity of 6+or-2 pC, minimum risetime of 4+or-1 ns, and temporal resolution of less than 0.1 mu s. The sensitivity is maintained for insulation test specimens with capacitances as large as approximately 10 nF, which is considerably greater than the limits of most conventional apparatus. Some representative test data concerning the characteristics of high-speed partial discharge phenomena in mica capacitors are presented to illustrate the diagnostic capabilities of the FDD. Several research applications for the FDD that could yield information about partial discharge mechanisms and their effects on the insulation system of modern power capacitors are stated. >