Under the hierarchical connection mode of ultra-high voltage direct current(UHVDC),commutation failure prevention control(CFPREV)of the non-faulty layer has problems such as start-up lag and advanced firing quantity is too small,so the system faces the risk of simultaneous commutation failure.To solve this problem,a commutation failure suppression strategy based on adaptive coordination firing quantity is proposed in the UHVDC hierarchical connection system,and the firing angle adjustment of CFPREV output of the faulty layer is introduced into the non-faulty layer.Therefore,the CFPREV of the non-faulty layer is fired in advance.Meanwhile,the voltage variation at both ends of the tie-line is introduced to dynamically track the fault evolution process and obtain the adaptive coordination firing quantity.An electromagnetic transient simulation model is built in PSCAD/EMTDC to verify the proposed suppression strategy.The results show that the proposed suppression strategy can effectively reduce the risk of simultaneous commutation failure of the high and low-end converter valves in the hierarchical connection mode.
关键词
特高压直流输电/分层接入/同时换相失败/换相失败预测控制/自适应协调触发量
Key words
ultra-high voltage direct current/hierarchical connection/simultaneous commutation failure/commutation failure prevention control/adaptive coordinated firing quantity
维普
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