PARTIAL DISCHARGE MEASURING METHOD OF POWER CABLE

PROBLEM TO BE SOLVED: To perform accurate measurement on which measuring sensitivity is hardly changed by detecting a pulse by discharge of a power cable, and measuring discharge electric charge by synchronizing at least two with each other by different three resonance frequencies of unintegral number of times. SOLUTION: Test voltage is impressed on a specimen cable 1 through a blocking impedance Zb, and a discharge pulse in the cable 1 is extracted through a coupling capacitor Ck. The pulse appearing in a detecting element 2 is splitted into three frequencies of 200kHz, 280kHz and 450kHz, and these are amplified by resonance amplifiers 4a to 4c, and respective outputs are connected to a peak meter 5, and a maximum value among the three frequencies is picked up, and is displayed. Therefore, measuring sensitivity not less than about 80%. is always obtained in the lengthwise direction of the cable 1, and partial discharge can be accurately measured without being influenced by a discharge generating position.