Consideration on Electrical Characteristics and Breakdown Lifetimes in 22.9[KV] Underground Distribution Power Cables

22.9[KV] 지중배전용 전력케이블의 전기적 특성과 파괴수명 고찰

Degradation diagnosis of XLPE insulated URD cables was accomplished through out new method which was to be analyzed by non-electrical experiments and synthesized by degradation points. To supplement this method, It was also carried out using several electrical analyses PD-q increased generally in proportion to the applied voltage and showed no uniform patterns in relation to the thickness of insulator. Leakage current was unequal according to the thickness of insulator and its range was from 20[nA] to 50[nA]. $Tan{\delta}$ had commonly a different tendency by means of temperature and frequency and also appeared higher at the outer part rather than inner part of insulator. Breakdown voltages were measured and breakdown lifetimes were predicted appling for Weibull distribution function. As a result, breakdown lifetime in failure cables was longer up to three times as much as general cables.