To provide a digital protection controller having a simple configuration while realizing a high speed sampling, and capable of determining defective part in an analog circuit.
The digital protection controller comprises: a harmonic signal generating part 100a which generates a plurality of harmonic signals; an analog-to-digital conversion part 100b which is provided with an analog filter which superimposes an analog AC electrical quantity of electric power system and the harmonic signal to perform a take-in filtering, and is provided with an A/D converter which converts an output of the analog filter into a digital electrical quantity; a common digital filter calculation part 100c which compresses a quantization error of the analog-to-digital conversion from an output of the analog-to-digital conversion part 100b, and decreases a sampling rate; and a monitoring arithmetic processing part 100e which calculates amplitude values of the plurality of harmonic signals superimposed by a digital Fourier transformation, calculates an amplitude value and an amount of variations of the amplitude value for each superimposed harmonic wave, and performs malfunction detection by identifying a circuit element which has characteristics fluctuation out of circuit elements based on the plurality of amplitude values.
KOMATSU SHINJI
YOSHIDA MASASHI
TAKAMI KAZUHISA
ITO EIJI
| JP2001223589A | 2001-08-17 | |||
| JP2007312525A | 2007-11-29 | |||
| JPS6188716A | 1986-05-07 | |||
| JP2001223589A | 2001-08-17 | |||
| JP2004248477A | 2004-09-02 |
Etsuo Tada
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