DC insulation supervisory relay

The utility model relates to a DC insulation supervisory relay, which is composed of a casing, a panel, a power supply circuit, an insulation supervision and detection circuit, an alarm parameter setting circuit, a window comparator circuit, an earthing indication circuit, and a switching signal output circuit. The utility model is used in a DC power supply system, and carries out real time monitoring for the insulation condition between the positive and the negative poles of the power supply and the earth. When the insulation condition is reduced to the lowest insulation level, indication signals and switching signals are sent out with sensitive and quick response.