抄録
Grounding equipment will be set up after general consideration required earth resistance and area of equipment. Generally, long distance is required to obtain the low resistance by equipment such as buried parallel conductors. It is successful method that the long parallel conductors are buried in the earth because of following reasons: (1) it is enable that the long conductors are buried along the road; (2) earth resistivity and earth resistance are easily estimated for the equipment buried near the surface; (3) the cost of grounding works are relatively less than the boring electrodes. It is very important to estimate accurately the earth resistivity because earth resistance in homogeneous earth is directly proportional to resistivity.
In this paper, the equation was presented in order to correct the apparent earth resistivity considering the length of the current and potential electrodes in earth. Subsequently, the equation was derived to obtain the earth resistance of buried short length conductor, and earth resistance and distribution of flowing current are investigated. When the grounding conductors are long, it is necessary to measure the accurate earth resistance paying attention to the position of the current and potential electrodes. Then, it was proved the range of the measurement errors due to the position of the potential electrode.
