Relay based protection system for grounded structures with a monitor potential applied of 24 V, there is a 3kv generator to simulate the overvoltage effect. The structure is simulated by the 1k resistor normally grounded, in an overvoltage occur the current flowing to ground its more than enaugh to activate the relay almost instantly and detach all the supply before damaging someone or something. The amount of peak voltage and current depends by the relay and resistors used. A too big resistor in the system may turn the measurement taken by the opamp not affordable
