Development of Optical Fiber Sensor for PartialDischarge Detection in High Voltage Power Transformers

Electricity is an indispensable part affecting the economy and prosperity of a country and reflects the growth of the nation. A healthy power system only can cope with the accelerated power demand scenario without compromising power quality. High voltage power transformers are significant and crucial equipment in an electrical system, subjected to various internal & external operating stresses. Failure of such utility in the electrical system creates unwanted power interruptions, which can even collapse the economy of a country. Insulation degradation is reported as a major cause of failure of these apparatus where partial discharge being the most significant signature and an indication of insulation deterioration, plays a vital role in causing the overall insulation degradation of the system as well. Therefore, condition monitoring of partial discharges in high voltage power transformer is essential to recognize early insulation collapse so that it can suggest proper corrective action to elevate system reliability and customer satisfaction. In this paper, condition monitoring through partial discharge detection has been carried out on different oil samples of a model transformer with the acoustic method by using temperature compensated Polyimide coated fiber Bragg grating-based acoustic sensor. The sensor is placed inside the model transformer, and then the measured partial discharge values are compared with the conventional electrical detection method. The proposed sensor provides a comparable detection capability over the conventional electrical detection method, which establishes fiber Bragg grating-based acoustic detection method as a superior alternative for online condition monitoring of high voltage power apparatus.