Voltage sensor diagnosis device and voltage sensor diagnosis method

A voltage sensor diagnostic method using a monitoring device for diagnosing a normality/abnormality of a voltage sensor that detects a circuit voltage in a system circuit of an electrical equipment system,

• the monitoring device including a main multiplier circuit, a subordinate multiplier circuit, and an abnormality diagnosis circuit, the method comprising:
• inputting the circuit voltage as a monitoring voltage into the main multiplier circuit and outputting a gain-non-inverted output signal without gain-inversion as a detected value of the circuit voltage;
• inputting the circuit voltage as a monitoring voltage into the subordinate multiplier circuit and outputting a gain-inverted output signal with gain inversion with respect to the gain-non-inverted output signal as the detected value of the circuit voltage;
• diagnosing an abnormality in the main multiplier circuit and the subordinate multiplier circuit, which are the voltage sensors, using the abnormality diagnosis circuit diagnoses based on the gain-non-inverted output signal and the gain-inverted output signal;
• converting the gain non-inverted output signal from the main multiplier circuit to a main monitoring voltage,
• converting the gain inverted output signal from the subordinate multiplier circuit to a subordinate monitoring voltage, and
• diagnosing an abnormality in the main multiplier circuit and the subordinate multiplier circuit when an absolute value of a difference between the main monitoring voltage and the subordinate monitoring voltage exceeds a difference diagnosis threshold.