Overvoltage limiter. When an overvoltage occurs, the voltage between the two terminals of the arrester does not exceed the specified fixed value, which protects the electrical equipment from overvoltage damage; after the overvoltage acts, the system can quickly return to normal state.

1. Valve plate

Resistor plates with nonlinear volt-ampere characteristics exhibit low resistance when over-voltage. Thereby, the voltage on the arrester is limited, and it is high resistance under normal power frequency voltage, which can limit the current through the arrester.

2. The rated voltage of the arrester

It is the effective value of the maximum allowable power frequency voltage applied between the terminals of the arrester. The arrester designed according to this voltage can work correctly under the temporary overvoltage in the specified action load experiment. It is an important parameter showing the operating characteristics of the arrester. But it is not equal to the system rated voltage.

3. Residual pressure of arrester

When the discharge current passes through the arrester, the maximum voltage value between its terminals.

4. Lightning impulse current

An 8/20 waveform impulse current. Due to the limitation of equipment adjustment, the actual measured value of Boqian time is 7～9us, and the median time of wave tail is 18～20us.

5. Operating impulse current

When the apparent wavefront time is greater than 30us and less than 100us, the wave tail at the half-peak time is as close as an impulse current twice the apparent wavefront time.

6. Square wave impulse current

A shock wave that rises rapidly to the maximum value, remains roughly constant within a specified time, and then quickly drops to zero.

7. Steep wave impulse current

It has an impulse current with an apparent wavefront time of 1us.

8. Impulse current tolerance (impact current forcing capacity)

Under the specified waveform (square wave, lightning, line discharge, etc.), the ability of the non-linear resistor to withstand the passing current is expressed by the amplitude and number of currents.

9. Action load test

It is used to determine the ability of a lightning arrester to reliably repeat actions under specified conditions. The experiment that simulates the lightning overvoltage action is called the lightning impulse action load test. The experiment that simulates the operation overvoltage action becomes the operation impulse action load test.

10. The protection range of the arrester

The maximum allowable length between the arrester and the protected equipment is shown, and the overvoltage on the protected equipment does not exceed the specified value within this range.

11. Continuous current of arrester

The current flowing through the arrester under continuous operating voltage, expressed in peak value or effective value.

12. Continuous operating voltage of the arrester

The effective value of the power frequency voltage that is allowed to be permanently applied to the arrester terminals during operation.

13. Power frequency reference voltage of arrester

The maximum peak value of the power frequency voltage on the arrester measured under the power frequency reference current divided by 2

14. DC reference current of arrester

The tributary reference current of the arrester is a certain current value near the inflection point of its volt-ampere characteristic curve. The changed value is related to the material and size of the resistor, and its value is about 1-20mA.

15. Pressure ratio of nonlinear resistor

The ratio of the residual voltage (peak value) of the nonlinear resistor under the nominal current to its reference voltage (peak value).

16. Pressure release level

The ability of the arrester to withstand internal fault currents. Under the specified short-circuit current, the porcelain pottery with the pressure release device lightning arrester will not explode (that is, the fragments will not fly out of the specified range during explosion). The pressure release current level is expressed by the effective value of the power frequency current.

17. Pollution tolerance

The pollution resistance of the arrester is mainly related to its overall structure, the creepage distance of the outer surface of the set and the shape of the umbrella skirt. The dirt on the surface of this sleeve, in addition to its surface flashover, will also cause uneven voltage distribution along the resistor. It can cause partial overheating of the resistor and cause damage. Regular cleaning and application of house paint can also improve the anti-fouling ability of the arrester.