摘要
阀电流是晶闸管型换流器运行状态的直接体现形式。为提升换流器的能观性,该文提出一种利用阀侧电流时序特征实时计算阀电流的方法。首先,利用交直流电流的时序特性预估每个阀的导通/关断状态。其次,根据阀状态计算换流器的旁通组数,利用多相旁通组间的并联关系,构造旁通回路方程。最后,计算阀电流,利用阀的单向导电性,校正阀关断状态和阀电流。仿真和录波结果表明:在不同的阀状态和旁通组数下,所提方法均能准确计算换相失败暂态过程及其故障恢复期间的阀电流,验证了其有效性。
As the essential element for electronic power conversion,the line-commutated converter is the core equipment in high-voltage direct current(HVDC)transmission systems.The safety of the converter equipment is critical to the stable operation of an AC/DC hybrid power grid after AC faults.When commutation failure occurs in the converter,the valve that experiences commutation failure is conducted for a long time with a high current,which may cause the valve to be damaged or burned,thereby exacerbating the security complexity between the converter and the grid.The valve current is a direct manifestation of the thyristor converter operating state.Recently,the existing studies on the converter thyristor valve current are mainly conducted through converter modeling,which involves the calculation of thyristor valve current.However,this method of valve current calculation must first assume the valve state.Nevertheless,especially during commutation failure and fault recovery,the assumed valve state may be wrong,resulting in incorrect valve currents.Therefore,a real-time calculation method of the valve current is proposed based on the temporal features of the converter terminal AC and DC currents.The protection and control capabilities of the equipment are optimized,and the reliability of the converter technology is improved by learning the accurate calculation of the thyristor valve current.According to the circuit constraints of the converter topology,the vector sum of the three-phase AC current is equal to 0 under the condition that there is no fault inside the converter.The KCL equations of the five nodes in the converter topology are combined to establish the correlation equation between the converter terminal current and the thyristor valve current.In order to determine the current distribution,the valve state should be introduced based on the topological equation.Firstly,the polarity characteristics of the converter terminal AC current and temporal features between the valves are utilized to estimate the valve state.Wh
作者
李晓华
殷珊珊
李昊
蔡泽祥
Li Xiaohua;Yin Shanshan;Li Hao;Cai Zexiang(School of Electric Power South China University of Technology,Guangzhou 510640 China;College of Information Engineering Henan University of Science and Technology,Luoyang 471023 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2023年第8期2116-2125,共10页
Transactions of China Electrotechnical Society
基金
河南省重点研发与推广专项资助项目(232102241042)。
关键词
阀电流
阀侧电流
时序特征
预估阀状态
旁通回路方程
阀关断状态校正
Valve current
valve-side current
temporal features
valve state estimation
bypass loop equation
valve blocking state correction
