EFFECTS OF VOLTAGE SURGES ON EXTRUDED DIELECTRIC CABLE LIFE - PROJECTUPDATE

Electric utility engineers have commented [1], [2] that extruded distr ibution cables frequently fail during or shortly after a thunder storm . These engineers also comment that failures often reoccur on cable ci rcuits where previous failures were located with a thumper. Linemen at Georgia Power often make similar comments. To investigate this observ ation, crosslinked (XLPE) and tree retardant crosslinked (TRXLPE) cabl e designs were subjected to accelerated water treeing tests. Samples w ere subjected to simulated lightning surges or simulated thumping surg es. Crosslinked cables removed after 15 years of service operation wer e also subjected to these surges. The results show that, in some cases , lightning surges do reduce extruded distribution cable life. Also, h igh level thumping surges appear to reduce cable life once cables are well aged.