Insulation DiagnosisforXLPE CablesUsing Damping Oscillating High Voltage

to60kV class XLPE cables arewidely usedand playing important roles inpowerdistribution andtransmission systems inJapan. Theagingdegradation isdominated bywater trees inthese XLPE cables. Therefore, watertreediagnosis with highprecision isquite important foroperation, maintenance and replaces planning ofthese XLPE cables. Theauthors havebeen investigating theapplicability oftheDampingoscillating high voltage (DOHV)tothewatertreedetection aswellasinsulation diagnosis forthese XLPE cables. Thispaperfirstly proposes the nondestructive insulation diagnosis usingDOHV application. Then,someempirical results obtained byitsapplication towater- treedegraded XLPE cable arediscussed. I.INTRODUCTION