However, more than 30 years have passed since their installation during the highest economic growth period, and many customers now confront their renewal requirements in Japan.
Environmental condition at their installation site is much different, depending on the local climate and the place; such as high temperature, high humidity, low temperature, and dusty and/or corrosive atomosphere.
Main circuit insulation system of the MV switchgear is classified as air/gas–insulation, solid insulation, and their complex. There are many varieties of insulation material combination and surrounding circumstances, which make it difficult to predict material degradation and to decide appropriate renewal time of the equipment.
Furthermore, there is a pressure to reduce maintenance cost and increase maintenance time period on the maintenance field, which is accelerating condition-based maintenance(CBM), rather than conventional time-based maintenance (TBM) planning . This committee has investigated the trend of maintenance technology of the MV switchgear, based on the study of domestic/overseas technical papers
| 1) | analysis of publicized questionare reports show that criteria for equipment renewal decision-making is changing, and efforts on reduction of ecological burden is starting in the maintenance field. |
| 2) | application of CBM is increasing , and challenge for reliability-centered maintenance(RCM) is starting to get the coordination between maintenance cost and operational reliability |
| 3) | new approaches of detecting insulation degradation are verified by the measurement of an optical reflection or acoustic emission of the equipment, and new procedures to judge the rest of life-expectancy of them is being challenged by applying Mahalanobis-Taguchi method. |
©2007. The Institute of Electrical Engineers of Japan