Analog link hardware failure detection circuit and method

The invention discloses an analog link hardware failure detection circuit and an analog link hardware failure detection method. The analog link hardware failure detection circuit comprises a summing device, a first low pass filter, a sampling retaining circuit, a multiplexer, an A/D (analog to digital) conversion circuit, a DSP (digital signal processor) chip, a CPU (central processing unit) and a signal generator, wherein an input end of the summing device is connected with four paths of output ends of a mutual inductor, an output end of the summing device is connected with an input end of the first low pass filter, an input end of the sampling retaining circuit is connected with an output end of the signal generator, an output end of the first low pass filter and an output end of the mutual inductor, an output end of the sampling retaining circuit is connected with an input end of the multiplexer, an output end of the multiplexer is connected with an input end of the DSP chip, and an output end of the DSP chip is connected with an input end of the CPU, a control end of the multiplexer, a control end of the signal generator and a control end of a power grid to be detected. The analog link hardware failure detection circuit and the analog link hardware failure detection method avoid wrong judgment caused by hardware failure, and guarantee reliable running of the power grid.