Research and Development of the Conductivity Testing System for Generator Circuit Breakers with Ultra-High Rated Currents

Generator circuit breakers (GCBs) are the key protection equipment for large hydropower stations. However, its conductivity performance at the rated current or short-circuit current is only measured during the type test, where the testing current can be as high as 30kA and is generally generated by the short-circuit impulse generator weighing tens of tons. This kind of testing equipment cannot be used on the installation site. This paper presents the research and development of a lightweight conductivity testing system for GCBs with ultra-high rated currents. In the system, supercapacitors and resistors are coordinated and controlled to generate a steady ultra-high testing current. In this way, the volume, weight, and cost of the testing system are significantly reduced. It can be flexibly used on the installation site. The test is performed on the experimental setup with a 30kA constant current lasting 15 seconds. The testing outcome verifies the effectiveness of the system and the accuracy of measuring ultra-high current and ultra-low voltage.