(1) When measuring the grounding resistance using an AC power source during the experiment, an independent power source should be used. Usually, a separate transformer should be used, and the neutral and grounding points should be opened to prevent errors caused by shunt or inability to raise the current. The voltage is estimated based on the impedance of the current circuit and the required current rise.
(2) In many substations, the overhead ground wire of the transmission line is connected to the grounding device of the substation, which can affect the measurement results of the grounding resistance of the substation grounding device. Therefore, before measurement, the lightning protection wire of the overhead line should be disconnected from the electrical connection of the substation grounding device.
(3) Due to the need to inject a large amount of current at the current pole, it can cause harm to nearby humans and animals. Therefore, a dedicated person should be responsible for monitoring during measurement;
(4) During the experiment, the current lead needs to flow a large amount of current, therefore, the current circuit needs to have a larger wire cross-section.