The Study and Application of On-site AC Dielectric Test System to 750kV Circuit Breaker

Abstract: The standard and time sequence of on-site AC dielectric test of 750kV breaker is presented in the paper. Based on series resonant principle, test method and parameters of each equipment in the test system are analyzed. On the basis of that, a whole set of on-site AC dielectric test system of 750kV breaker is configured. Actual instance shows that AC dielectric test for main circuit and fracture of 750kV breaker can be completed successfully.     

Key words:  circuit breaker, AC dielectric, quality factor, series resonant     

750kV breaker is one of pieces of core equipment for 750kV super-high voltage power grid. After being installed, AC dielectric test is conducted on site and insulation condition is inspected, which can found possible defects caused during the transportation, installation and debugging. That can greatly improve safety and stability of the equipment after they are put into use. Statistics shows that fault probability of breaker with AC dielectric test is far lower than those without AC dielectric test. Hence, AC dielectric test has become the most important hand-over test after the breaker was installed.