基于状态空间分析的整流侧极母线接地故障清除方案评估  

Clearing Strategy Assessment of Pole Bus Grounding Fault on Rectifier Side Based on State Space Analysis

作　　者：谷相宏 张程 卫志农[2] 孙毅 冯轩 殷友伟 GU Xianghong;ZHANG Cheng;WEI Zhinong;SUN Yi;FENG Xuan;YIN Youwei(EHV Branch Company,State Grid Jiangsu Electric Power Co.,Ltd.,Nanjing,Jiangsu 211102,China;College of Energy and Electrical Engineering,Hohai University,Nanjing,Jiangsu 210098,China)

机构地区：[1]国网江苏省电力有限公司超高压分公司,江苏南京211102 [2]河海大学能源与电气学院,江苏南京210098

出　　处：《广东电力》2022年第10期109-116,共8页Guangdong Electric Power

基　　金：国家重点研发计划项目(2018YFB0904500);国家电网有限公司科技项目(SGTYHT/21-JS-223)。

摘　　要：整流侧极母线接地故障发生后,最大短路电流可至正常运行电流的10~20倍,为此需对极母线接地故障清除方案进行系统性评估,选择最优清除方案以减小故障对区域电网冲击。首先建立极母线接地故障数学模型,利用状态空间方程,结合特征根分析,解析故障电流时域表达式;随后,结合现有控制保护方案分析故障极电压、电流衰减与过渡电阻的相关性,进一步分析运行极直流电流恢复的影响因素。分析表明:整流侧极母线永久性接地故障发生后,故障极电流衰减特性与过渡电阻、故障清除方式相关;低阻接地故障侧进入旁通运行后,故障电流衰减时间较长,造成中性线电压波动,运行极直流电流建立过程中发生振荡。基于特高压直流工程实时仿真系统(real time digital system,RTDS)对整流侧极母线接地进行仿真,仿真结果表明,故障发生后整流侧选择不进入旁通方式运行有利于故障极直流电流衰减及运行极直流电流恢复。After pole bus grounding fault occurs on the rectifier side,the maximum short-circuit current can reach 10~20 times of the normal operation current.Therefore,it is necessary to evaluate the pole bus grounding fault removal scheme systematically,and select the optimal removal scheme to reduce the impact on the regional power grid after the fault.Firstly,the mathematical model of pole bus grounding fault is established,and the time-domain expression of fault current is analyzed by using state space equation and eigenvalue analysis;Then,combined with the existing control and protection schemes,the correlation between the voltage and current attenuation of the fault pole and the transition resistance is analyzed,and the influencing factors of the DC current recovery on the operating pole are further analyzed.The results show that after the permanent pole bus grounding fault occurs on the rectifier side,the attenuation characteristics of fault pole current are related to transition resistance and fault clearing mode.After grounding fault side with the low resistance enters the bypass operation,the attenuation time of the fault current is long,resulting in the fluctuation of the neutral line voltage and the oscillation in the process of establishing the DC current on theoperating pole.Based on the real time digital system(RTDS)of ultra-high voltage DC project,the bus grounding fault on the rectifier side is simulated.The simulation results show that the rectifier side does not enter the bypass mode after the fault occurs,which is beneficial to the DC current attenuation of fault pole and the DC current recovery of operating pole.

关 键 词：极母线接地 状态空间 时域表达式 旁通方式 实时仿真系统 

分 类 号：TM721[电气工程—电力系统及自动化] TM744.3