HVDC送端系统振荡引发受端换相失败的机理分析  

Mechanism Analysis of Receiving End Commutation Failure Caused by Sending End Oscillation in HVDC Transmission System

作　　者：郑乐 吴晶[1] 徐衍会[1] 孙英云[1] 刘崇茹[1] Zheng Le;Wu Jing;Xu Yanhui;Sun Yingyun;Liu Chongru(School of Electrical and Electronic Engineering North China Electric Power University,Beijing 102206 China)

机构地区：[1]华北电力大学电气与电子工程学院,北京102206

出　　处：《电工技术学报》2024年第9期2743-2754,共12页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划“储能与智能电网技术”重点专项2022年度项目“无常规电源支撑的大规模新能源发电基地稳定运行及直流送出关键技术”(2022YFB2402700)资助项目。

摘　　要：高压直流输电系统送、受端存在电气耦合及两端的控制配合,因此,送端振荡可通过系统控制逻辑、电气量及控制量变化等影响受端系统的运行状态,增加了受端换相失败的风险。现有工作主要研究了送端大扰动引发受端换相失败的现象与机理,通过对标准直流系统进行小信号分析,发现直流系统中存在低频频段的固有振荡频率,一旦交流系统发生相近频段的振荡,将可能诱发直流系统共振。在此基础上,首先分析共振引起系统电气量以及控制量的波动对换相失败的影响,通过HVDC的准稳态方程分析共振后直流电流上升导致关断角下降,进而引发首次换相失败的机理;然后从两端的控制系统出发,研究逆变侧控制切换引发后续换相失败的机理;最后对CIGRE直流输电标准测试系统进行验证,并结合换相失败发生机理对换相失败的抑制策略进行了初步讨论。Strong electrical and control coupling exists between the sending and receiving ends of a high voltage direct current(HVDC)transmission system.Therefore,disturbances on the sending end can affect the operation state of the receiving end system through changes in control logic,electrical,or control quantities,increasing the risk of commutation failure(CF)on the receiving end.The phenomenon and mechanism of CF at the receiving end caused by large disturbances at the sending end have been studied in existing literature.This paper identifies the existence of inherent oscillation modes with frequencies situated in the low-frequency range in the system.When oscillations of similar frequencies manifest in the sending AC system,resonance in the DC system becomes alikely outcome,causing CF in the receiving end.Without timely control of this resonance,it triggers switching of constant current control and constant extinction angle control at the inverter side.An uncontrolled extinction angle during control switching will likely cause subsequent CFs,even DC blocking.Therefore,discovering the mechanism of such CF is important to contribute to the operational safety and stability of HVDC transmission systems.Firstly,the whole process of the CF caused by the sending end oscillation is analyzed using simulation curves from the CIGRE benchmark HVDC system.According to the simulation results,four different stages have been identified after the first detection of the sending end oscillation.Secondly,the eigen values of the CIGRE benchmark HVDC system are calculated using a small-signal stability model,and the inherent oscillation modes of the system are determined.A special mode,in which the sending end current controller plays a pivotal role,is identified based on participation factor values.The frequency of the special mode of the CIGRE benchmark system is 1.2 Hz,located in the low-frequency range.When the sending system encounters oscillations of nearby frequencies,resonance is easily induced,causing corruption in the sending en

关 键 词：高压直流输电 送端振荡 受端换相失败 机理分析 

分 类 号：TM614[电气工程—电力系统及自动化]