Dr. Farhan Mehmood

Nowadays it becomes more and more important to operate the electrical equipment efficiently. To achieve this, condition-based maintenance is a good way to reduce maintenance time and cost. For condition-based maintenance, partial discharge is an important tool to indicate the insulation conditions. Partial discharge (PD) is short release of current caused by the buildup of electric field intensity in a finite region. This localized current manifests itself as an electrical pulse that is measurable at the output of the test object. PD event occurs due to voids, air gaps and gas bubbles present in insulation. The void region has a lower dielectric constant than the surrounding material, creating a capacitance. A partial discharge can then occur when the electric field difference across the void exceeds minimum breakdown field strength. There are many techniques used for PD detection. The apparatus present in high voltage lab is using �electrical detection� technique. In this method, a high voltage is applied across the test object along with a coupling capacitor in parallel with it. The charge that is lost by void is provided by capacitor and this apparent charge is measured. Based on this charge, the severity of PD event is judged. During aging of a defect in high voltage electrical devices, different PD mechanisms can occur. PD detection can be used as a tool to judge the state of the device and the quality of its manufacture. We will only test the PDs occurring in transformers and power cables in this project. In this project, the PD measuring set available in high voltage lab of UET is deployed. PD equipment present in the high voltage laboratory of the university is not functional since 2002 due to some unknown reasons. Also, we have no helping material and staff to operate this equipment. Our task is to bring this equipment into working condition to enhance the testing capability of high voltage lab and the revenue generated to university each year.

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