Relay switching at zero-crossing point of grid voltage to eliminate the EFT interference

A relay application system was proposed to achieve the relay switching exactly at the zero-crossing point of the grid voltage. It can test the delay time between the control signal and relay actual action time under different ambient, assembly positions and load conditions. After consider the delay time of the relay action, the relay can switch exactly at the zero-crossing point of the grid voltage to avoid the grid voltage flicker during the relay action and eliminate one of the fast transient/burst resources in the grid. The operation principle was verified by the prototype and experimental results.