Discussion on Precision Measurement for the Grounding Grid of Substation
Bin Chen · Gao dianya jishu · 2008
The theory foundation of the grounding resistance measurement of the substation is a fall-of-potential method,and the all-purpose measurement method is a three-electrode method.The current many methods of the grounding grids measurement only pay attention to the resistance component or the magnitude of the grounding impedance,therefore,this paper proposes two kinds of improvement methods: series resistance and the improved wattmeter methods,by the two methods,the resistance and reactance component of the grounding grid's grounding impedance can be obtained very conveniently.During the measurement,the mutual-inductance between voltage and current leading wires can not be neglected,particularly in large substation grounding grid.The induced voltage in the voltage leading wire caused by the current of the current lead wire is non-orthogonal,mutual-inductance between the measurement lead wires has the resistance component.,the ground impedance by measurement minus the mutual-inductance between the measurement lead wires,the real ground impedance can be obtained.