PURPOSE: To perform correctly the calibration of the partial discharge measurement of a power cable in hot-line state by injecting a calibration pulse into a direct detection system, detecting the calibration pulse by a measurement system, and making not affected by the attenuation of the calibration pulse.
CONSTITUTION: A partial discharge measurement equipment 25 is connected into the grounding cable 23 of a sheath 22 of a power cable 20. A calibration pulse oscillator 27 is conneted parallel to the measurement equipment 25, and the detecting sensitivity of the calibration pulse is found by the measurement system containing several impedances of a characteristic impedance 26 between a high voltage conductor 21 of the cable 20 and the sheath 22, a ground impedance 28 between the grounded sheath 22 and the ground, and a coupling impedance 27 between the high voltage conductor 21 and the ground. The calibration of a partial discharge measurement of the power cable 20 is very correctly performed without being affected by the attinuation of the pulse occurring when the calibration pulse is propagated through the power cable 20, by connecting the calibration pulse oscillator 27 parallel to a detection system, injecting the calibration pulse into the direct detection system, and detecting the calibration pulse by the measurement system.
TOTANI ATSUSHI
ENDO TAKESHI
SUZUKI HIROSHI
IMAI TOMOAKI
HAGITANI MIKIO
HITACHI CABLE