Application of Optoelectronic Technique for Detection of Air Corona, Surface Discharges at Cable Termination and End winding of Stator Coil

Partial discharge in high voltage equipment like generators, motors, transformers, power cables etc. occur due to various manufacturing defect sites or due to aging of the insulation under various stresses. Occurrence of surface discharges at the termination of cables, end winding of stator bars, surface discharges along the supporting insulators in case of gas insulated systems are common. Prolonged partial discharge activity may lead to breakdown of the insulation resulting in forced outages and financial implications. Partial discharge measurement is a promising tool for detection of incipient faults in power equipment. This paper presents a novel optoelectronic technique for detecting air corona, surface discharges at cable termination and end windings of stator coil. A laboratory investigation was carried out in controlled conditions to understand the detection capability of optoelectronic technique for these types of discharges. An experimental setup consisting of collimating lens, fluorescent optical fiber, common optical fiber cable, fiber optic coupler, photomultiplier tube modules and pc-based oscilloscope for data acquisition was designed and used for measurements. The results are presented and discussed.