System and method for automatically cutting off ground fault power supply during debugging of secondary equipment

The invention discloses a secondary equipment debugging ground fault power supply automatic cut-off system and method, relates to the technical field of electric power automation, and solves the problem that a fault that alternating current is connected in series with a direct current system is difficult to deal with in the prior art. The system is provided with a voltage collection unit, a processor unit and an execution unit, the voltage collection unit firstly isolates a DC voltage signal in a DC system through an RC circuit module, and then collects the remaining AC voltage signal through a sampling circuit module; and finally, the digital signal is converted into a digital signal through an A/D conversion module and then is transmitted to the processor unit to judge an alternating current voltage signal, whether an alternating current signal exists in the direct current system is judged through a threshold value comparison mode, and if the judgment result is that the alternating current signal exists, a