When you select a surge protection device, it is important to pay attention to the parameter below,
a. The voltage should be ≤ Uc;
b. Up<maximum impulse withstands;
c. Different protectors should be selected according to various grounding system and protection mode.
According to different systems the surge arresters protected, different parameters should be pay attention to,
1. For surge arresters for protection of power supply systems, and photovoltaic surge arresters,
The operating voltage (Uc): The choice of operating voltage is vital when selecting a SPD. When choice the Uc value, besides meet relevant standard, the fluctuation of the network or the Max. continuous fault voltage also should be taken into consideration.
The protection level (Up): The Up value of the surge protection devices (surge arresters) is chosen according to and should be less than the impulse withstanding voltage of the equipment to be lightning surge protected. But it does not mean that the lower of the Up, the better of the surge protection devices (surge arresters, SPD) protection effect. Usually for the equipment connected to the network of 220V/380V, its withstanding impulse voltage can meet the requirement of 2000-2500V. So the SPD with Up<2500V can protect the equipment efficiently.
The alarm indicator : In order to monitor the operating condition of the surge protectors, when surge protectors damaged, the user should know it and change the damaged surge protectors module immediately. In order to realize the monitoring function, it should chose the surge protectors with indicator.
Choice of the associated switching element: All surge protection devices (surge arresters, SPD) are fitted with a built-in thermal disconnector. However, they must be equipped with an upstream protection element for protection against short-circuit currents.