云广与贵广Ⅱ回直流输电系统共用接地极设计

Common Grounding Electrode Design for Yunnan-Guangdong and Guizhou-Guangdong Ⅱ DC Transmission Project

为了不对系统运行产生太大影响并节省工程用地和建造费用,云广特高压直流输电工程和贵广Ⅱ回高压直流输电工程广东侧考虑采用共用接地极模式建造。根据系统运行条件、使用寿命以及人身安全的要求确定了建设共用接地极的参数,对该参数采用了矩量法和边界元法相结合的接地计算数值方法,并针对大罗州和李屋两个极址分别设计了一套共用接地极方案。这两套设计方案既能满足系统要求又能符合国家标准,不会对人身安全产生影响,可供建设共用接地极使用。

Yunnan Guangdong 800kV ultra high voltage and Guizhou Guangdong Ⅱ 500kV DC transmission projects are under construction in Guangdong province. Each HVDC project should have a grounding electrode. But there are already three HVDC grounding electrodes built in Guangdong province. So it is difficult to find proper locations to build two grounding electrode for both projects. Several studies already done show that common grounding electrode would not influence the operation performances of two HVDC transmission projects. In order to reduce both construction area and cost, Yunnan Guangdong 800kV ultra high voltage and Guizhou Guangdong Ⅱ 500kV DC transmission projects will share a common grounding electrode in Guangdong province, The influence of HVDC transmission projects on the environment nearby is smaller by sharing a common grounding electrode than that by building two grounding electrodes separately for each project. Parameters and methods required to design a common grounding electrode for two HVDC transmission projects are different with building a grounding electrode for a single project. Yunnan Guangdong ultra high voltage DC transmission project and Guizhou Guangdong Ⅱ DC transmission project will share a common grounding electrode in Guangdong side in order to reduce both construction area and cost. Common grounding electrode would not influence the performances of two HVDC transmission systems but different parameters are required to build it. According to the system conditions and personal safety requirements, the paper provides several parameters for the electrode design. With the parameters a method coupling moment method with boundary element method is used in the paper to design the common grounding electrode in two locations Daluozhou and Liwu where are possible to build a common grounding electrode. Analysis results of common grounding electrode can satisfy the system requirements and national safety standards for grounding electrodes.