摘要
针对光伏电站接入柔性直流系统的交流侧故障特征受双端电力电子设备输出特性影响而与传统交流系统存在显著差异的问题,提出结合系统拓扑、换流器故障控制策略的稳态故障特征分析方法,以明晰设备间的序分量耦合特性。首先,针对光伏电站接入柔性直流系统的交流侧不对称短路进行稳态故障特征分析,揭示了双端电力电子设备输出电流的受控特征,以及换流器并网点电压与输出电流之间的序分量耦合关系。然后,重点分析了当光伏电站采用负序电流抑制策略时,柔直换流器成为了系统唯一的负序电源,得出了单相接地短路和相间短路的故障相差流特征与柔直换流器的负序电流存在定量关系的结论。同时指出了柔直换流器的负序电流限幅极大地改变了系统的序分量特征。最后,通过某大规模光伏电站接入柔性直流系统的电磁暂态仿真,验证了稳态故障特征分析结论的正确性,为电力电子化新型电力系统保护原理的研究提供了理论与技术支撑。
To address the issue that the AC-side fault characteristics of photovoltaic(PV)power plants integrated into VSC-HVDC differ significantly from those of traditional AC systems due to the influence of power electronic devices at both ends,a steady-state fault characteristic analysis method is proposed that incorporates system topology and converter fault control strategies,in order to clarify the sequence-component coupling among devices.First,steady-state fault characteristics of AC-side asymmetric faults in PV power plants connected to VSC-HVDC are analyzed.The results reveal the controllable nature of the output currents from power electronic devices at both ends,as well as the relationship of sequence-component coupling between converter’s grid-connected point voltage and its output current.Then,it is emphasized that when the PV power plants adopt the negative-sequence current suppression strategy,the HVDC converter becomes the sole source of negative-sequence current in the system.It is further concluded that,under single-phase-to-ground faults and phase-to-phase faults,the fault phase current differences exhibit a quantitative relationship with the negative-sequence current of the HVDC converter.It is also noted that the negative-sequence current limiting of the converter significantly alters the system’s sequence-component characteristics.Finally,the correctness of the steady-state fault characteristic analysis is verified through electromagnetic transient simulations of a large-scale PV power plant integrated into a VSC-HVDC system,providing theoretical and technical support for the research of protection principles in power electronics dominated new power systems.
作者
马红月
李岩
张涛
曹润彬
郑涛
郝治国
MA Hongyue;LI Yan;ZHANG Tao;CAO Runbin;ZHENG Tao;HAO Zhiguo(School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China;Electric Power Research Institute of China Southern Power Grid,Guangzhou 510063,China)
出处
《电力系统保护与控制》
北大核心
2025年第24期100-110,共11页
Power System Protection and Control
基金
国家自然科学基金项目资助(U23B20112)。
关键词
光伏电站
柔性直流
稳态故障特征
交流故障
控制策略
序分量耦合
PV power plant
VSC-HVDC
steady-state fault characteristics
AC fault
control strategy
sequence-component coupling
