Abstract
The ageing and deterioration of insulation in high voltage (HV) plants have been a source of concerns to
utilities. Breakdown of insulation leads to failures of HV equipment. The ageing and eventual failure of
insulation in a high voltage curTent transformer (JHVCT) is the subject of investigation in this paper. A
lumiiped parameter model ofHVCT is developed. This model is used to study the influlence of deteriorating
and failed iinsulation on the state variables of the HVCT. Somie possible scenarios that could lead to a CT
failure are investigated in this paper. For all the scelarios considered, steady alid transient equations
relating the state variables of the mlodel have been developed and analyzed. The objectives of these
analyses are to establish the behavioural claracteristics of the state variables, establish the interactions
between these variables, and investigate the possible generations of harmonics under the various scenarios
of deteriorating and outright failure of insulation in the CT. The paper concludes with a discussion of the
results obtained