가스절연개폐장치(GIS)용 UHF 부분방전검출장치를 통한 유지보수 운영기준 적합성 연구

Abstract

High voltage and highly-capacitive power have been demanded for electric power facilities in all industrial sectors because of the rapid development in economy. Gas insulated switchgear (GIS) was also replaced with indoor, compact, and closed-terminal types in accordance with emphasis on maintenance, safety and facilitation. However, the deterioration and internal flaws in GIS facility increases the possibility to bring about the insulation troubles. There is another drawback of the long duration in the accident-restoration caused by the impossibility of verification for the fault section within easy range of a technician in the existing GIS facility. Therefore, the partial discharge (PD) measurment techniques were used in the applied voltage state, which is the examination detection of the electromagnetic waves and ultrasonic waves of the PD originated from the several causes inside the GIS in advance of the troubles. Although several prevention diagnosis techniques were developed using measuring methods and applied to the filed facilities, they had the different the detailed criteria of management between manufacturers of diagnostic equipment, remote diagnostic companies, and principal agents of management as well as the criterion point was not commonly settled in the first judgment of abnormal symptom. In this thesis, the criterion point of PD detector for GIS was obtained by verifying the huge amount of data in the installed and operated systems under Korea Railroad corporation. An inappropriateness of the same applicable number was studied because the event occurrence of the filed facility was variable in accordance with the installed surroundings. An inadequateness of the criterion, which was fixed in the maintenance manual by the daily occurrence number of the abnormal events, in each level was also investigated. The criterion point for the judgment on existence/absence of the PD occurrence in GIS was determined with realignment of criterion value through the reflection of the corresponding warning number by detecting pC and PPS values of the ultra high frequency (UHF) sensor in abnormality and the adjacent sensor. As a result, the scientific and systematic judgment of criterion in the maintenance was secured not only to decrease in economic losses by use-suspension of the operating equipments but also to prevent the accidents by the PD in advance.