The Zinc peroxide arrester installation

It should be installed near the side of the distribution transformer

The metal oxide arrester (MOA) is connected in parallel with the distribution transformer during normal operation, the upper end is connected to the line, and the lower end is grounded. When there is an overvoltage on the line, the distribution transformer at this time will withstand the three-part voltage drop generated when the overvoltage passes through the arrester, lead wire and grounding device, which is called residual voltage. In these three parts of overvoltage, the residual voltage on the arrester is related to its own performance, and its residual voltage value is certain. The residual voltage on the grounding device can be eliminated by connecting the grounding down conductor to the distribution transformer shell, and then connecting it to the grounding device. How to reduce the residual voltage on the lead becomes the key to protect the distribution transformer. The impedance of the lead is related to the frequency of the current passing through it. The higher the frequency, the stronger the inductance of the wire and the greater the impedance. It can be seen from U=IR that in order to reduce the residual voltage on the lead, the impedance of the lead must be reduced, and the feasible way to reduce the impedance of the lead is to shorten the distance between the MOA and the distribution transformer to reduce the impedance of the lead and reduce the voltage drop of the lead, so It is more appropriate that the arrester should be installed closer to the distribution transformer.
The low-voltage side of the distribution transformer should also be installed

If there is no MOA installed on the low-voltage side of the distribution transformer, when the high-voltage side surge arrester discharges the lightning current to the earth, a voltage drop will occur on the grounding device, and the voltage drop will act on the neutral point of the low-voltage side winding through the distribution transformer shell at the same time. Therefore, the lightning current flowing in the low-voltage side winding will induce a high potential (up to 1000 kV) in the high-voltage side winding according to the transformation ratio, and this potential will be superimposed with the lightning voltage of the high-voltage side winding, resulting in the neutral point potential of the high-voltage side winding rises, breaking down the insulation near the neutral point. If MOA is installed on the low-voltage side, when the high-voltage side MOA discharges to raise the potential of the grounding device to a certain value, the low-voltage side MOA starts to discharge, so that the potential difference between the low-voltage side winding outlet terminal and its neutral point and the shell decreases, so that Can eliminate or reduce the influence of "reverse transformation" potential.
The MOA ground wire should be connected to the distribution transformer shell

The ground wire of the MOA should be directly connected to the distribution transformer shell, and then the shell is connected to the earth. It is wrong to connect the grounding wire of the arrester directly to the ground, and then lead another grounding wire from the grounding pile to the transformer shell. In addition, the ground wire of the arrester should be as short as possible to reduce the residual voltage.