The arrester which uses zinc oxide semiconductor as a resistor material, such type of arrester is known as a metal oxide surge arrester or ZnO Diverter.
The arrester which uses zinc oxide semiconductor as a resistor material, such type of arrester is known as a metal oxide surge arrester or ZnO Diverter. This arrester provides protection against all types of AC and DC over voltages. It is mainly used for overvoltage protection at all voltage levels in a power system. The metal oxide surge arrester has the following merits:
1. It eliminates the risk of spark over and also the risk of shock to the system when the gaps break down.
2. It eliminates the need of voltage grading system.
3. At the normal operating condition, the leakage current in the ZnO is very low as compared to other diverters.
4. There is no power follow current in ZnO diverter.
5. It has high energy absorbing capability.
6. ZnO diverters possess high stability during and after prolonged discharge.
7. In ZnO diverter, it is possible to control the dynamic overvoltages in addition to switching surges. This results in economic insulation coordination.
|Type||System Rated Voltage (kV)||Rated Voltage (kV r.m.s)||Continuous Operating Voltage (kV r.m.s)||DC Reference Voltage (kV)||2ms Square Wave Current (A)||Residual Voltage(≤kVp)||Continuous Current Resistance Component mA(peak)|
|30/60μs Steep Impulse||8/20μs Lightening Impulse||1/10μs Operating impulse|