How to measure the grounding resistance

2, 102 electronic meter to measure the grounding body, when the water penetrates the contact voltage and current pole, the contact resistance due to poor contact is large, which affects the measured true value. This method is only used when there is no place to insert voltage and current poles, but it must be that the real water penetrates into the soil, and the voltage and current must be in good contact with water. Minimize contact resistance and reduce errors.        There are two important parameters in the grounding device: 1. Grounding resistance value; 2. Grounding grid structure. It now appears that although the structure of the grounding grid and the equipotential of the system are important, the low-resistance grounding device is the basis for normal and safe operation of the equipment. Especially in the lightning protection grounding, it is necessary to discharge the lightning current of several tens of KAs to the earth in an instant. The smaller the grounding resistance is, the faster the flow is, and the time for maintaining the high potential after the lightning strike is short, and the danger is small. In short, the smaller the grounding resistance, the better the effect, and the safer the protected object.

        For this situation, we have the following Suggestions：
        1. The length of the measuring line is increased, especially when rolled together. Due to the large inductance, the measured value is very high. Therefore, when we measure the grounding value of a tall building, it is not accurate to measure the grounding value of the elongated line. This is because when the high-rise building is measured, there is a certain resistance value between the grounding lead of the high-rise building and the ground (R ground). The test line that is connected to the ground meter from the measurement point above the high-rise building is present in the air. Line inductance. (WL) Therefore, the resistance measured by the grounding point of the high-rise building is R=R ground + WL+R ground. Ground measurement grounding resistance R = R ground.

       2. 102 electronic meter to measure the grounding body, when the water penetrates the contact voltage and current pole, the contact resistance due to poor contact is large, which affects the measured true value. This method is only used when there is no place to insert voltage and current poles, but it must be that the real water penetrates into the soil, and the voltage and current must be in good contact with water. Minimize contact resistance and reduce errors.