New techniques for monitoring the insulation quality of in-service HV apparatus

New online monitoring techniques have been developed for use on HV systems. An online testing device was developed to measure partial discharge and dielectric loss angle (DLA) of in-service HV instrument transformers and is used as a fast screening device. A continuous DLA monitor for in-service transformer bushings and current transformers has also been developed and installed at a 132 kV substation. These techniques considerably enhance HV plant maintenance programs and have a significant impact on future plant monitoring strategies.<
>