一种抑制气体绝缘开关装置暂态地电位升高的措施

Suppression of Transient Ground Potential Rise in Gas Insulated Substation

在分析外壳地电位升高原因的基础上,提出了用电磁暂态程序计算外壳地电位升高的等值计算模型.通过对外壳地电位升高的计算,表明外壳地电位的升高足以危害与气体绝缘开关装置(GIS)相连的外围设备.为了防止外壳地电位升高对GIS的外围连接设备的影响,提出用线路金属氧化物避雷器限制快速暂态过电压的幅值,用氧化锌阀片来改善GIS与外围设备的连接方式以限制外壳地电位升高.计算结果表明,加装金属氧化物避雷器不仅可以抑制快速暂态过电压,而且可以较为有效地抑制外壳地电位升高,且氧化锌阀片的残压越低,其对外壳地电位升高的抑制效果越好.对国内某550kVGIS的外壳地电位升高进行了现场实测,结果表明计算波形与实测波形比较吻合.

Based on analyzing the generating reasons of temporary ground potential rise (TGPR), a calculation model is suggested to calculate TGPR with electro-magnetic transient program (EMTP). The results show that TGPR is higher enough to damage the adjacent equipment connected with gas insulated substation (GIS). To prevent the detrimental TGPR, it is suggested that line-type metal-oxide arrester is adopted to suppress the very fast transient overvoltage (VFTO), and ZnO disc to improve the connection between GIS and adjacent equipment, and the lower residual voltage of ZnO disc, the better suppression effect on VFTO and TGPR A site test of TGPR in a domestic 550 kV GIS is carried out. The waveform of site test coincides with the calculated one very well.