【摘要】 为研究双极运行的特高压直流输电系统中单极接地故障过电压,采用相模变换法分析了双极运行的特高压直流输电系统单极接地故障。首先建立故障时的模量电路,分析线路不同端口性质下健全极过电压的波形特征和幅值,然后结合模量电路分析,以云广直流输电工程为对象,建立了双极直流输电系统的单极接地故障模型,计算和分析了多种因素如故障接地电阻、直流滤波器的工作状态、平波电抗器的布置方式等的影响以及故障时健全极沿线的过电压幅值分布情况。结果表明,直流滤波器的投入与否将改变直流线路端口的阻抗性质,对故障时的过电压影响显著:投入直流滤波器时,中点接地故障时健全极过电压最大可达1.76p.u.,平波电抗器布置方式对健全极过电压幅值无影响;未投入直流滤波器时,平波电抗器布置方式将直接影响到健全极过电压的幅值。更多还原

【Abstract】 In order to study the overvoltage caused by monopolar grounding fault under bipolar mode in Ultra High Voltage DC(UHVDC)system,the paper analyzes the monopolar grounding fault by use of phase-modal transformation method.By establishing the modal circuit under the fault,maximum overvoltages on healthy pole with different kinds of terminals are deduced.Combined with modal component analysis and for verification purpose,model of Yun-Guang UHVDC project are then built to simulate the overvoltages on the healthy pole under monopolar grounding fault.The influential factors including grounding fault resistance,working status of dc filters and dc reactor configuration are then analyzed.And overvoltages distribution along the health pole are also calculated,it is presented as a result.The results indicate that the maximum overvoltage on healthy pole is influenced significantly by on/off working status of dc filters.When dc filers are in use,the maximum overvoltage on healthy pole can reach 1.76 p.u.and the dc reactor configuration has no effect on the amplitude of overvoltage.The dc reactor configuration will directly influence the maximum value when there is no dc filter.更多还原