To shorten period for grounding factor investigation and recovery work in the field, by conducting, in a far control slave station, fast Fourier transformation(FFT) of grounding waveform data when the grounding fault is generated and discriminating class of grounding, by collating waveform data of the grounding class previously inputted to memory and frequency distribution.
An analog signal from a switch 201 on a pole is analyzed and judged though a digital arithmetic operation in a digital means 30. A far control slave station 202 conducts analysis by FFT of a grounding waveform data and collates frequency distribution of the FFT-analyzed grounding data and the frequency distribution data of grounding class inputted to the far control slave station memory to discriminate the grounding class. As a result, the far control slave station 202 itself mounted on the same pole as the switch 201 of the pole can discriminate the class of accident. As a result, the adequate urgent process of the accident recovery means can be made quickly from the adequate accident class discrimination.
FURUTA TAKU
OSAJIMA SHINJI
