Today, China's independent research and development of the world's first 200 kV high voltage DC circuit breaker - Zhoushan soft direct system Zhouding converter station DC circuit breaker - for the first short circuit test, and achieved success, its performance in the actual system short circuit has been fully tested, for China's DC break related technology has accumulated experience.

On the basis of the traditional single-pole grounding short-circuit test, the bipolar short-circuit test was carried out for the first time in Zhouding converter station DC short-circuit field test, and the UAV was used for the first time, and the DC circuit breaker was successfully operated under various short-circuit conditions. The successful short-circuit test fully verifies the operation performance of DC circuit breaker in the process of system short-circuit fault, which marks the maturity of HVDC breaking technology.

At the end of 2016, 200 kV HVDC circuit breaker, as the world's first HVDC circuit breaker put into engineering application, was successfully applied to Zhoushan five-terminal flexible DC power transmission project. The circuit breaker can break the fault current generated by a 200 kV HVDC transmission line in 3 milliseconds, 100 times faster than a human blink. The 200 kV HVDC circuit breaker has overcome the world-class technical problem that HVDC current is difficult to be quickly disconnected, and has achieved a major breakthrough in the field of research and development and manufacturing of HVDC core equipment. Up to now, this circuit breaker is still the only DC circuit breaker put into actual operation in the world.

On the basis of more than two years of operation test of Zhoushan DC circuit breaker, State Grid Zhejiang Electric Power Co., Ltd. carried out the short circuit test. The test includes positive and negative pole single-pole grounding test, bipolar short-circuit test and other items. By monitoring the action behavior of converter valve, DC circuit breaker and control protection during short-circuit test, the correctness of the design function and action index of related equipment is tested. By detecting the transient current, voltage on both sides of DC circuit breaker and electromagnetic field change in the test environment, the anti-interference ability of converter valve, DC circuit breaker and control protection and other related equipment is assessed.

"In simple terms, the single-pole ground test is more to test the insulation performance of the DC circuit breaker, and the bipolar short-circuit test is more to test the transient high-current breaking ability." State Grid Zhejiang Electric Power Liu Li introduced, "In reality, two kinds of short circuit may be encountered." By artificially creating two short-circuit environments, the test tested the response ability of DC circuit breakers and related equipment such as control protection in extreme cases, and comprehensively collected a variety of valuable data and parameters to accumulate experience for technical improvement.

In order to carry out the test successfully, State Grid Zhejiang Electric Power set up a test team composed of experts from many enterprises, universities and scientific research institutes, formulated detailed standards and technical specifications, combined with the actual situation of the existing project, prepared technically feasible, controllable risk test plan, and improved the drill script; In terms of test guarantee, do a good job in the safety protection of the test site, carry out surrounding environmental management and personnel guidance, and minimize the impact of the test on the surrounding area.

The test verifies the breaking function of HVDC circuit breaker in Zhoushan flexible straightening project, the logical correctness of DC circuit breaker and converter valve cooperation, collects various necessary data and parameters under DC short circuit fault, and accumulates experience for subsequent DC short circuit test in DC power grid.