Evaluation of the use of Near Infrared Spectroscopy (NIR) in on-line Monitoring of Power Transformer Insulation Oil

To maximize the lifetime expectance of power transformers, it is important to develop tools to monitor and to give diagnose information, allowing for real-time detection of incoming failures. Information from analysis of gases dissolved or free in insulating oil is one of the most valuable tools in evaluating the health of a transformer and has become an important part of preventive maintenance programs. The condition of the oil greatly affects the performance and the service life of transformers, and on-line monitoring has become a reliable method to ensure the safe operation of transformers. An on-line monitoring of dissolved gases generated by electrical transformers in operation was developed, which can be used as an important parameter for the detection of faults and monitoring the chemical degradation of mineral insulation oil. This paper proposes a method to analyze the generated gases, based on Near Infrared Spectroscopy (NIR) through a developed prototype that can be adapt on the Buchholz transformer relay. The combination used of NIR spectroscopy and chemometric tools has allowed for obtaining information over the samples. Recent developments of chemometrics software and computer technology have made NIR analysis the practical choice for process analysis applications.