未断开接地装置和架空地线连接时接地电阻的测量误差研究

Grounding Resistance Measurement Error Analysis for Grounding Device and Overhead Gounding Line Connection not Dsconnected

分析了未断开接地装置和架空地线连接时接地电阻的测量误差来源,指出实际流经接地装置的电流小于电流测量值是产生测量误差的根本原因。通过建立数学模型研究了变电站接地电阻值、电流回路电阻值、杆塔接地电阻值、架空地线类型的改变对接地电阻测量误差的影响。为了减小大电流法测量接地装置接地电阻的误差,应当断开接地装置和架空地线的连接并令测试范围内杆塔的架空地线与地绝缘。

The sources of the grounding resistance measurement error when the grounding which is not disconnecting device connected with overhead grounding line are analyzed, it is pointed thatthe primary cause of the measurement error is that ,the actual current flowing through the grounding device is less than the measured value. The substation grounding resistance value, the current loopresistance value, tower grounding resistance value, and the effect of the changes in the type of overhead grounding line on the grounding resistance measurement error are studied through establishing amathematical model. In order to reduce the grounding resistance measurement error by large current method, the grounding device should be disconnected with the overhead grounding line and the over-head grounding line should be insulated with the earth.