变电站镀铜钢接地网设计关键技术

Key Technology for Substation Coppered Steel Grounding Network Design

铜材的热稳定系数取值会随生产工艺的不同而不同,其取值大小将直接决定镀铜钢接地体的截面积大小,即直接决定了工程造价和工程技术方案的选择。针对目前我国的国家标准、行业标准、企业标准均未对镀铜钢的热稳定系数取值做出精细描述,结合国际标准,提出了一种针对镀铜钢热稳定系数的计算方法。以±500 kV从化换流站(国内第一个成功应用镀铜圆钢接地体的变电站)为示例,从导电性、热稳定性、耐腐蚀性以及经济性等方面对变电站接地网常用的纯铜、镀铜钢和热镀锌钢3种接地材料进行比较,认为镀铜钢作为变电站接地体材料,其技术性能与纯铜绞线差别不大,其经济性优于纯铜绞线,但该经济性优势需以准确设定其热稳定系数为基础。

Thermal stability factor value of copper product differs due to productive technology which may affect directly sec- tional area of coppered steel grounding body, namely choice for project cost and technology program. Aiming at problems that there is no precise description for thermal stability factor value in national standard, industrial standard and enterprise standard, this paper presents one method for calculating thermal stability factor of coppered steel combining with interna- tional standard. Taking an example of ＋ 500 kV Conghua convertor station which is the first substation applying coppered steel grounding body, it compares three grounding materials including pure copper, coppered steel and thermal galvanized steel commonly used in substation in aspects of electrical conductivity, thermal stability, corrosion resistance and economy. It considers that as grounding material for substation, the technical performance of coppered steel is of small difference with that of pure coppered stranded wire while its economy is better than pure coppered stranded wire and it is required for cor- rectly setting thermal stability factor to judge economic advantages.