Development of a 20 kV damped oscillating voltage generator

This study describes the design and development of a 20 kV rated damped oscillating voltage (DOV) generator that can detect the partial discharge (PD) condition in 6/10 kV power cables. A complete system using a novel high-voltage switch consisting of a series of connected insulated gate bipolar transistors (IGBTs) is designed and tested. The switch consists of ten identical IGBT switch units, a multiple output isolated power supply system and a trigger unit. Physically, it is a 60 cm diameter fan-shaped printed circuit board. To coordinate the various tested objects and to comply with the IEC 60060-3 standards, an air-core inductor is calculated to precisely fit the most general application conditions using the magnetic vector potentials method. A laboratory prototype is assembled and tested. Waveforms illustrating the performance of the IGBT switch and the output of the DOV are presented. Finally, an application-oriented test demonstrates that the scheme can successfully complete the PD test and PD location test for a cable sample.