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The power supply lightning protector is installed outside the protected equipment, and its functions are as follows:

① When there is no surge in the power system, it has no obvious influence on the operating characteristics of the power system;

② When there is a surge in the power system, the power supply lightning protector has a low impedance, and the surge current is discharged through the power supply lightning protector and the voltage is limited to its protection level;

③ After discharging the surge, the power supply lightning arrester can quickly return to the high impedance state after extinguishing any possible power frequency freewheeling in time.

Due to the complexity of the environment and the difference of the characteristics of the main components of the power supply lightning arrester, there are two failure modes, open circuit and short circuit.

Main causes of failure mode of power lightning arrester

Temporary over-voltage and switching over-voltage in low-voltage system, long-term voltage fluctuation caused by poor quality of power grid system and frequent lightning stroke in power supply system are the external reasons for the failure of power supply lightning arrester;

The pulse life, long-term charging life of ZnO varistor and the insufficient design of power frequency freewheeling interrupting capacity of gas discharge tube are the internal reasons for the failure of power lightning arrester.

When the failure of power supply lightning arrester is in open circuit mode (provided by a nonlinear element of power supply lightning arrester itself, or by internal or external disconnector in series with power supply lightning arrester, and disconnected from power supply system), the failure of power supply lightning arrester has little impact on the system, so it is difficult to be found, and the protected equipment is still working, but the equipment is no longer affected It's protected.

Therefore, the power lightning arrester needs a fault indicator (remote and / or on-site) to give a disconnection signal. Users can find the problem in time and replace the failed power lightning arrester to ensure that the equipment can still be protected before the next surge.

When the failure of power supply lightning arrester is in short-circuit mode, the failure of power supply lightning arrester has a very serious impact on the system, and the short-circuit current in the system flows through the failure of power supply lightning arrester. At this time, if there is no suitable device to separate the failure of power supply lightning arrester from the system in time, the excessive release of energy when the short-circuit current is connected may cause serious fire, so the power supply lightning arrester itself is very important Short circuit current tolerance is very important.

No matter what kind of failure mode of power lightning arrester appears, it is very important to install the special disconnector of power lightning arrester at its front end. It can cut off the power frequency current in time to protect the power lightning arrester from fire when the power lightning arrester fails, and ensure the continuity of power supply when the power lightning arrester fails.