| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively monitor an insulation deterioration state of a high voltage power facility via simple means.SOLUTION: A high voltage insulation monitoring method includes: detecting a zero-phase current Iwhich flows to a power cable 13, in accordance with occurrence of an earth-fault accident in the power cable 13 by means of a zero-phase current transformer ZCT 15 installed in the power cable 13 of a high voltage cable run 12 connected to a non-grounded system cable run; and determining that the earth-fault accident is an in-premise earth-fault. A clamp type current transformer 18 is connected to a shield wire 17 of the power cable 13 installed in the high voltage cable run 12, a zero-phase current Iwhich flows to the shield wire 17 when an earth-fault accident occurs, is detected by the clamp type current transformer 18 and by multiplying a phase difference of the zero-phase current Idefining a phase of the zero-phase current Ias a reference, it is determined that the earth-fault accident is an in-premise earth-fault. |
