Study Of Method On Grounding Resistance Measurement With Short Electrode Wire And New Decreasing Resistance Technology

Grounding system of power plant and transformer substation is one of important parts of to keep reliable of the power system, ensure the safe of equipments and person. Grounding resistance is important technical parameter of grounding system. It needs to be measured accurately to ensure the grounding system to work during the system fault before system operation or after operation for some time. Today Electrode wire in measurement methods of grounding resistance is so long as to result in large influence and large amount of workload. It is great realistic significance that method with short electrode wire for grounding resistance measurement has been proposed. On the other hand, how to decrease the grounding resistance economically and effectively in a limited area with high soil resistivity becomes an important question of power system for discussion.The paper studies the method of grounding resistance measurement and the new technology of decreasing the grounding resistance. The study includes the method and theory of resistance measurement with short electrode wire, the using and design method of kongfu grounding equipment.(1)With the principle of measuring resistance, the paper carries through the theory analysis about possibility of measurement method with short electrode wire. By using GPC grogram, the paper calculates the variety of grounding potential with different placements of grounding rods. On the basis of calculations and analysis, the model of grounding grids and current-electrode are presented.(2)The measurement error using the 0.618 method to measure grounding resistance with short electrode wire is discussed. The analysis results show that the measurement results must be modified, or change the placement of voltage-electrode. The paper recommends that the placement of voltage -electrode is 0.509s when the distance from the border of grounding grids to current-electrode is s that is the long border length of grids.(3)The paper use two-layer theory to describe non-uniform soil. With the different two-layer soil model, some conclusions and formula that have great reference value are presented numerically.(4)Considering the combination of the calculation of measuring placement, the digital signals processing technology, the frequency-changing technology, the single chipcomputer technology and the measurement data of fieldwork, the measuring brainpower apparatus can largely make use of the man-machine conversation technology and measuring knowledge. By using this apparatus, the errors between the measured results and real grounding resistance can be eliminated largely.(5)With the research of theory and the analysis of field data, principle and method using kongfu grounding equipment to decrease the grounding resistance were studied. The paper provides scientific method and explains for decreasing grounding resistance in a limited, high soil resistivity area by using kongfu grounding equipment.