Distribution Surge Arrester

Distribution surge arrester is a protective device used in medium-voltage power distribution systems to protect electrical equipment against lightning and switching overvoltages. It is commonly installed on overhead distribution lines, distribution transformers, substations, and other electrical installations.

Most modern distribution surge arresters use zinc oxide (ZnO) varistor blocks as their main protective components. They are typically designed with silicone rubber polymer housings, offering good resistance to pollution, moisture, and outdoor weather conditions. Their lightweight construction also makes transportation and installation easier.

Distribution surge arresters are available for power distribution systems operating at 11 kV, 15 kV, 22 kV, 24 kV, 33 kV, and 36 kV. Depending on the model and application requirements, they can be designed and tested in accordance with IEC 60099-4 or IEEE C62.11.

Metal Oxide Surge Arrester Working Principle

A metal oxide surge arrester (MOA) uses zinc oxide (ZnO) varistor blocks with nonlinear voltage-current characteristics. The electrical resistance of these blocks changes with the applied voltage, allowing the arrester to limit transient overvoltages in power distribution systems.

Under normal operating voltage, the ZnO varistor blocks remain in a high-resistance state, allowing only a small leakage current to flow. When a lightning or switching overvoltage occurs, their resistance drops rapidly, allowing surge current to flow through the arrester to ground while limiting the voltage across the protected equipment.

After the overvoltage subsides, the ZnO varistor blocks return to their high-resistance state, and the arrester continues operating normally. This process helps prevent insulation damage to distribution transformers and other connected electrical equipment.

Distribution Surge Arrester Specifications