HVDC送端交流系统故障引起换相失败的机理分析  

Mechanism Analysis of Commutation Failure Caused by Fault of HVDC Sending End AC System

作　　者：朱海 郝亮亮[1] 和敬涵[1] 郭智琳 陈争光 Zhu Hai;Hao Liangliang;He Jinghan;Guo Zhilin;Chen Zhengguang(College of Electrical Engineering Beijing Jiaotong University,Beijing 100044 China;State Grid Corporation of China,Beijing 100031 China)

机构地区：[1]北京交通大学电气工程学院,北京100044 [2]国家电网有限公司,北京100031

出　　处：《电工技术学报》2023年第16期4465-4478,共14页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金委员会-国家电网公司智能电网联合基金资助项目(U2066210)。

摘　　要：通常认为高压直流输电(HVDC)的换相失败是由受端交流系统或换流阀故障引起,但工程实践中发现,送端交流故障同样可能引发逆变器的换相失败。目前,针对此类换相失败的研究较少,且大多局限于传统的母线电压幅值特征,对其机理研究不够深入。鉴于此,首先通过分析故障后的交直流系统响应,指出与一般受端故障不同,送端交流故障引发的换相失败发生在故障切除后的恢复阶段,且受端母线电压幅值大小不是其关键因素。在此基础上,对故障切除后的受端母线电压相位特性进行剖析,得出有功功率的恢复会导致受端母线电压相位前移,进而压缩关断裕度并造成触发延迟。进一步地,在不同故障程度下分析了系统换相失败过程对应的触发指令与直流电流的变化。结果表明,当送端故障相对轻微,受端保持定关断角(CEA)控制时,相位前移及突增的直流电流是导致逆变器换相失败的主要原因;而在送端故障程度加深,受端切换至定电流(CC)控制后,相位前移是换相失败的主要原因。最后,基于CIGRE标准模型,仿真验证了分析的正确性。It is generally believed that the commutation failure of high-voltage direct current transmission(HVDC)is caused by the failure of the receiving-end AC system or the converter valve.However,in engineering practice,it is found that the sending-end AC system failure may also cause the commutation failure of the inverter.At present,most research is limited to the amplitude characteristics of the traditional bus voltage,and its electrical coupling and control coordination needs to be studied.Firstly,by analyzing the response of the AC/DC system after the sending-side fault occurs,it is pointed out that,different from the general receiving-side AC fault,the commutation failure caused by the sending-side AC fault generally occurs in the recovery stage after the fault is removed.Moreover,the magnitude of the bus voltage is not a key factor in such commutation failures.On this basis,the phase characteristics of the bus voltage at the receiving end after the fault is removed are analyzed using the relationship between the active transmission power and the phase angle of the bus voltage.Based on the phase characteristics,the possible commutation failure risk is obtained.The analysis shows that after the fault is removed,restoring the active power transmitted from the sending system to the receiving end will lead to the phase advance of the commutation bus voltage at the receiving end.The phase advance of the bus voltage will not only make the commutation voltage zero-crossing point earlier,but also it will directly compress the commutation area,reduce the turn-off margin from two aspects,and increase the risk of commutation failure.On the other hand,the phase advance will also cause the actual trigger angle of the inverter to exceed the trigger command value,which delays the triggering of the commutator valve on the inverter side during the recovery process and induces commutation failure.In addition,in order to more comprehensively consider other influencing factors of commutation failure,according to the controller respo

关 键 词：换相失败 送端交流故障 相位偏移 关断角 触发指令 

分 类 号：TM711[电气工程—电力系统及自动化]