MONITORING METHOD FOR OIL LEAKAGE OF OF-CABLE LINE

PURPOSE:To objectively judge oil leakage occurring state by obtaining a recovery line for time of oil amount difference between phases from oil amount data of insulation oils of phases, and detecting the slopes of the lines by a statistic method. CONSTITUTION:A monitor 10 receives oil amount data of insulation oil of phases, and detects oil leakage from variation in oil amount difference between phases. That is, the oil amount data of the phase are received every ten minutes for two days, and oil amount difference between the phases is obtained by an oil amount difference calculator 11. Then, a recovery line of oil amount difference to time is obtained by a recovery line calculator 12. Further, the slope of the line is obtained by a slope extractor 13. The slope of the line corresponds to leakage oil amount per unit time. Accordingly, the slope is detected by a malfunction phase detector 14, a significance detector 15, a leakage oil generating state discriminator 16 by means of dispersive analyzing method to judge oil leakage generating state.