... 500Vdc, Uc=620Vdc, In=20KA,Imax=40KA photovoltaic system spd1,photovoltaic power system (PV system) , DC 2,Un=500Vdc, Uc=620Vdc, ... 20KA/40KALT-40/S DC surge protective device, protect ... against lightning surge voltages in solar system (photovoltaic power supply system).These units ...