Research And Application For Measure To Limit Arc Grounding Over-voltage

This thesis aims at the different electric running mode and running condition of the neutral point grounding measure in 6~66kV domestic electric system, integrates the problems which existing in the measure to limit the arc grounding over-voltage through compensating method of the arc eliminating coil in the 6KV system of our factory , it includes the main parts as following:Firstly, the thesis analyzed the damage of the electric equipment, which caused by the intermittent arc grounding over-voltage in 6~66kV neutral point indirect grounded electric system. In theory, it pointed out that measure can decrease the probability of the arc grounding over voltage only, but can't removal it at all.Secondly, basing on the research of the limit the arc grounding over-voltage's recent usage in our country and the investigation of limit the arc grounding over-voltage's new technology—the equipment to prevent from arc-eliminating voltage and to choose the line, the thesis proposed the assumption to adopt this new technology in 6KV system of 110kV transformer substation, and verified the equipment's feasibility to eliminate the arc grounding over-voltage on the basis of the result of 1:1 simulative experiment.Finally, during the technology renovation, making use of the equipment to prevent from arc-eliminating voltage and to choose the line, as for the neutral point grounding system, we altered the former one which was grounded by arc eliminating coil to indirect grounding way in our factory.The result of the actual application shows that it owns the visible advantage compared with the older one. Not only it restricts the arc grounding over-voltage, but also protects the electric equipment's insulation performance because the three phase mosaic over-voltage protection can control the generatrix's over-voltage at a low level. In addition, as a result of the equipment adopts the non-compensating way, when signal phase's failure arising, the capacitance's current which flowing through the failure pointis the maximal current of the system to ground. It greatly improved the sensitivity > reliability and veracity of the small current equipment to choose line by introducing the arithmetic of maximal increment.