DC SPD(Surge Protective Device)supplier, protect against lightning surge voltages in solar system (photovoltaic power supply system). These units must be installed in parallel on the DC networks to be protected and provide common and different modes protection. DC SPD installed location are recommended at both ends of the DC power supply line (solar panel side and inverter/converter side), ely if the line rounting is external and long. High energy MOVs equipped with specific thermal disconnectors and related failure indicators.