Study on measuring the grounding resistance of grounding grid with short lead wire
Method of measuring the grounding resistance with short lead wire is applied to test the ground resistance of some simulated grounding grid when the resistances of the grounding conductor are considered simultaneously. The position of voltage electrode is determined through the calculation when the position of current electrode is given in advance. It is showed by test result that the method of measuring the grounding resistance with short lead wire can obtain the value of ground resistance with relatively high precision. Moreover, the length of current electrode is shortened. It provides a more scientific and suitable way for the ground resistance measurement of grounding grid in field. The relation between the position of voltage electrode and the length of current electrode is also considered.
A novel measurement system for substation grounding resistance
A measurement system including a notebook PC for substation grounding resistance has been developed. The measurement method is based on short lead wire of current electrode and a frequency inverter AC source with relatively low power. Results of computation and measurement based on this novel method and the traditional method are presented to illustrate the effectiveness of the measurement system.
A PC based ground impedance measurement instrument
A PC-based instrument for ground impedance measurements is presented. The instrument injects a transient electric current between the ground under measurement and an auxiliary ground, and it measures ground potential differences (GPDs) around the ground under measurement. The GPD measurements are processed with software which rejects external noise by the use of correlation methods. Estimation methods are used to extract the ground potential rise and ground impedance. The final result is the ground impedance versus frequency in a user-selected frequency range. The instrument has been constructed and field tested by three electric utilities. >