吉林台一级水电站接地电阻的测量

Measurement of Earthing Resistance for the Xinjiang Jilintai-ⅠHydropower Station

吉林台一级水电站装机容量460MW。有4回220kV出线。电站地处高土壤电阻率地区,接地装置面积达213000m2,前3次测量用同一种直线法,电流、电压线紧靠在一起沿弯曲公路放线,测得电站接地电阻不满足电站运行要求。由于测量并非直线,同时测量系统互感带来很大的误差,决定重新测量。第4次测量采用任意夹角法,避免互感的影响,测得电站的接地电阻为0.244Ω,接触、跨步电位差都在允许值以内,满足了电站运行要求。

Jilintai- Ⅰ hydropower station has the capacity of 460MW and four 220kV outgoing lines. The hydropower station is located in the region of high soil resistance, where the earthing device has an area of 213000m^2. Same method of straight lines was used for the first 3 times measuring. The lines for both voltage and current were laid closely and curvedly along the road. The earthing resistance that measured in that way can not meet the requirements of the hydropower station. A new measurement was made for the reason of the former measuring method was not under the straight line and the error caused by the induction of the measuring system itself. The free angles method was adopted for the fourth earthing resistance measuring as to avoid the influence of self-induction. The earthing resistance of the measurement is 0.244 and the contact voltage, as well as the step voltage are all within the permitted values and can meet the operating requirement of the hydropower station.