Influence of Length of Current Electrode in Grounding Resistance Measurement by Fall-of-Potential Method
Hong Rao · Power System Technology · 2006
The influence of current electrode's length on measuring error of substation grounding resistance is researched, and the current electrode lengths for different soil textures are obtained. When the method that the current and potential electrodes are in opposite direction is used to measure the grounding resistance, the measured result is smaller than its actual value, however this measured value can be used as the lower limit of measured substation grounding resistance. After the distance between measuring electrode and grounding mesh is determined by global positioning system (GPS), the grounding resistance can be more accurately measured by fall-of-potential method. Actual measured results show that if the lead of current electrode is too short, the position of compensating point of actual grounding resistance's voltage electrode can be obtained by means of auxiliary analysis method.