| As a new type of power equipment,there is no relevant test standard for DC circuit breaker currently.Equivalent breaking test scheme needs to be further studied.Compared with AC circuit breaker breaking progress with alternating zero current point,the DC circuit breaker needs to establish transient interruption voltage by the commutation process between different branches,which is higher than the DC system voltage to suppress the fault current.However,voltage-related stress of key components is neglected in existing breaking test in the transient interruption voltage establishment.For the Zhangbei Project 500kV DC circuit breaker,the electrical stress of each key component in the transient interruption voltage establishment was analyzed in this thesis.More detailed and comprehensive evaluation indexs for the breaking test of DC circuit breaker were proposed,which provide technical reference standard for DC circuit breaker breaking test.In this thesis,LC breaking test circuit was analyzed deeply.According to the equivalent parameter k,proposed in this thesis,the test circuit parameter design scheme was carried out by theoretical calculation and simulation analysis.Finally,the experiment was carried out for the 50kV breaker unit,and the experimental result was in line with simulation expectation.The synthetic test of the full operating condition of the breaker was analyzes in this thesis,and the synthetic test circuit parameters were designed by step-by-step,to simplify the design method of the synthetic test circuit parameters.The optimized synthetic test circuit parameters were obtained.Finally,the LC test circuit and the synthetic LC test circuit were compared and analyzed for their equivalence and economy.The synthetic test circuit is a better choice.As above,value of this paper mainly fills the gap that key electrical stress during transient interruption voltage establishment is neglected in existing DC circuit breaker breaking test.The parameter design scheme of the breaking test circuit provides an economical and feasible solution for the "100%" recurrence of the proposed key stress. |
