4个直流输电工程共用1个接地极运行方式的研究  

Study on Four HVDC Systems Sharing a Common Ground Electrode

作　　者：饶宏 李岩 黎小林 张晓[2] 尹晗[2] 何金良[2] 

机构地区：[1]南方电网科学研究院,广州510080 [2]清华大学电机工程与应用电子技术系电力系统及发电设备控制和仿真国家重点实验室,北京100084

出　　处：《高电压技术》2012年第5期1179-1185,共7页High Voltage Engineering

基　　金：国家自然科学基金(50737001);国家重点基础研究发展计划(973计划)(2009CB724504)~~

摘　　要：针对溪洛渡-广东±500kV同塔双回直流输电工程,基于避免在受端开辟极址、建设新的接地极以节省占地面积和工程造价,为此,研究了将双回溪洛渡工程共用到云广特高压和贵广Ⅱ两回直流输电系统共用的鱼龙岭接地极,实现4回直流公用该接地极的可行性。研究了4条直流系统在受端公用接地极时,各种可能的多回同极性单极大地运行工况及其出现的概率和短时最大入地电流。研究表明,4回直流系统共用接地极后,在双回同时同极性单极大地运行时,原鱼龙岭接地极设计能满足要求,无需扩建。考虑直流工程实际运行情况和系统控制要求,4回共极址的直流工程出现3回同时同极性单极运行概率极小,而出现4回同时同极性单极运行概率几乎为0。综合考虑技术经济要求,可认定原鱼龙岭接地极的设计能满足继续共用溪洛渡直流工程的要求。针对理论上可能出现的3回同时同极性单极大地运行的短时大电流,提出了将现有接地极扩建为3环结构,能够满足对应工况下短时大入地电流条件下跨步电压值不超标。Focusing on the two circuits of Xiluodu-Guangzhou --500 kV DC transmission engineering, we analyzed the possibility that the double circuits Xiluodu-Guangdong projects share the Yulongling common ground electrode, which was built for Yunnan-Guangdong ultra high voltage DC transmission project and Guizhou-Guangdong 1I DC transmission project, to avoid building a new ground electrode so as to save land and construction cost. Moreover, we analyzed all possibilities of multiple projects operating in ground return mode synchronously, and respectively discussed their probabilities and short-time maximum currents through the earth. Analysis shows the constructed Yulongling ground electrode can satisfy all possible conditions of two projects operation in ground return mode when four projects share the Yulongling ground electrode. Considering the actual operation conditions and system control demands of DC transmission systems, the probability when three projects operate in ground return mode synchronously approaches zero, and the probability when four projects operate in ground return mode synchronously is zero. After combining with the technical and economic aspects, the existing Yulongling ground electrode can satisfy the demands of being shared by four projects. In accordance with the theoretically existed probability which three projects operate in ground return mode synchronously, the scheme that the Yulongling ground electrode was expanded as three-ring structure was proposed, satisfying the step voltage demands when large ground-return current passes through it.

关 键 词：共用接地极 跨步电压 直流输电 接地极温升 4回直流 单极大地运行 

分 类 号：TM862[电气工程—高电压与绝缘技术]