The most effective approach to suppressing the first commutation failure(CF)of the LCC-HVDC link at fault inception is to advance firings of the inverter,and the commutation failure prevention(CFPREV)control is the mo...The most effective approach to suppressing the first commutation failure(CF)of the LCC-HVDC link at fault inception is to advance firings of the inverter,and the commutation failure prevention(CFPREV)control is the most commonly used method in practical engineering.However,it is discovered in this study that there exist a few serious defects in its original scheme,and thus targeted vital corrections were made.Furthermore,an interesting phenomenon termed the plateau effect,which states that an excessive advancement of firings will contrarily and inevitably lead to more commutation failures,is also revealed and analyzed.It turns out that the inherent commutation dents of the Graetz bridge should be primarily responsible,which bridges the knowledge gap and further enhances the cognition of the limitation of CFPREV control,and it may also be conducive to the design of related control parameters.Simulation results then validate the necessity of these presented corrections and confirm the existence of the plateau effect.展开更多
电网换相换流器高压直流(line commutated converter high voltage direct current,LCC-HVDC)在逆变侧交流系统故障时,容易出现换相失败。换相失败预测(commutation failure prevention,CFPREV)是避免换相失败的主要手段,为解决其给定...电网换相换流器高压直流(line commutated converter high voltage direct current,LCC-HVDC)在逆变侧交流系统故障时,容易出现换相失败。换相失败预测(commutation failure prevention,CFPREV)是避免换相失败的主要手段,为解决其给定阈值不能满足所有故障工况的问题,从换相失败原理出发,分析CFPREV启动阈值和触发角调节量增益与换相失败之间的关系、交流母线电压对启动阈值和触发角调节量增益的影响以及故障时刻对启动阈值的影响,提出以交流母线电压为指标,对启动阈值和增益进行优化,在一定程度上提升了换相失败免疫能力。通过PSCAD/EMTDC电磁暂态仿真平台进行仿真验证,结果表明优化后的CFPREV相比于常规的CFPREV能够更有效地抑制换相失败的发生。展开更多
基金This work was supported in part by the National Key Research and Development Program of China(2016YFB0900600)in part by the Science and Technology Project of State Grid Corporation of China(52094017000W).
文摘The most effective approach to suppressing the first commutation failure(CF)of the LCC-HVDC link at fault inception is to advance firings of the inverter,and the commutation failure prevention(CFPREV)control is the most commonly used method in practical engineering.However,it is discovered in this study that there exist a few serious defects in its original scheme,and thus targeted vital corrections were made.Furthermore,an interesting phenomenon termed the plateau effect,which states that an excessive advancement of firings will contrarily and inevitably lead to more commutation failures,is also revealed and analyzed.It turns out that the inherent commutation dents of the Graetz bridge should be primarily responsible,which bridges the knowledge gap and further enhances the cognition of the limitation of CFPREV control,and it may also be conducive to the design of related control parameters.Simulation results then validate the necessity of these presented corrections and confirm the existence of the plateau effect.
文摘电网换相换流器高压直流(line commutated converter high voltage direct current,LCC-HVDC)在逆变侧交流系统故障时,容易出现换相失败。换相失败预测(commutation failure prevention,CFPREV)是避免换相失败的主要手段,为解决其给定阈值不能满足所有故障工况的问题,从换相失败原理出发,分析CFPREV启动阈值和触发角调节量增益与换相失败之间的关系、交流母线电压对启动阈值和触发角调节量增益的影响以及故障时刻对启动阈值的影响,提出以交流母线电压为指标,对启动阈值和增益进行优化,在一定程度上提升了换相失败免疫能力。通过PSCAD/EMTDC电磁暂态仿真平台进行仿真验证,结果表明优化后的CFPREV相比于常规的CFPREV能够更有效地抑制换相失败的发生。
