| By investigating the design and calculation methods of ground grid of a substation in Wuhai district, the problems in the design methods are analyzed. The advantages and disadvantages of the common calculation method and its applicability are discussed. A calculation method of substation ground resistance in mountain area, which can be easily used by a common engineer, is suggested. Choose several typical schems to design the grounding grids and compared with those datum. The ground resistances of several substations are calculated by using two methods, and the calculated results are compared with the measured ones. The first method is based on the reduced formula in the handbook of electrical engineer. The second method is based on the two-layer soil model, and charts are used in the calculation of the ground resistance of substations. The results show that the second method is better than the first, and suitable in engineering design. For substation ground problems in mountain area, the measurement methods of resistivity of soil and ground resistance of grounding grid are analyzed and the measures decreasing the grounding resistance is studied.
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