Status Quo and Trends of Insulation Monitoring and Diagnosis Methods for Electric Power Apparatus in Japan

As a research aiming at obtaining basic information useful for the development of maintenance-free insulation, the status quo and trends of insulation monitoring and diagnosis methods for electric power apparatus that have been done in Japan are analyzed by reviewing about 8800 reports published for the last 50 years. It is found that the accuracy of monitoring and diagnosis has been improved well and unmanned monitoring and diagnosis have been developed significantly with the introduction of measurement systems using sophisticated computer-aided analyzing and fiber-optic monitoring techniques. Further implementation of such sophisticated methods in the whole area of insulation monitoring and diagnosis should even increase the total reliability of power apparatus, which will undoubtedly reduce the necessary personnel and costs to maintain the apparatus.