Distributed system for online determination of the insulation condition of high voltage capacitive bushings

This work presents a new distributed system for online assessment of the insulation condition of high voltage capacitive bushings. These components are the third most common source of failures of power transformers. The proposed system uses passive resistive sensors, installed at the testing tap of the capacitive bushings, and acquisition interfaces to measure the leaking current and to determine the bushings' insulation parameters, C₁ and $PF$. The system also determines the resulting sum of the leakage currents' phasor's of a three-phase set of bushings and enables the comparison between corresponding bushings of parallel transformers. The results obtained so far demonstrate that the proposed system can determine the insulation parameters of operating high voltage capacitive bushings.