Partial discharge detection by TEV sensors for power transformer

Power transformers are amongst the most important equipment for utilities as well as private company using these have voltage apparatus. However, a significant number of these power transformers has been commissioned in the sixties or seventies and accordingly are close to the end of their useful life. The decision to prolong the operation of these equipment implies an increasing risk of in-service failure, which not only would lead to unscheduled cost for the replacement of the failed unit but also might damage other equipment. The critical part of oil-paper power transformer is their insulation system that gradually deteriorates during normal operation due to a combination of thermal, electrical and environmental stresses. This degradation could lead to the inception of partial discharges which in turn will further accelerate the degradation process. It is therefore important to monitor the partial discharge activity using capacitive couplers or dielectric windows, or when neither is possible, Transition Earth Voltage (TEV) sensors. The purpose of this project is to compare the sensitivity of TEV sensors with conventional capacitive couplers by PD measurement in lab as well as in the field. The experimental results will also be compared with numerical simulation.