Development of Overhaul Planning Support Program For Oil Immersed Transformer

Summary

In these more than ten years, the asset management technique has attracted interest of responsible members of utility companies for maintenance strategy of electric power equipment because asset management tools seem to be the possible measures that can provide the cost reduction methods. From the view point of effective asset management, operating condition data, inspection data and diagnostic data are being gathered, and attempts are being made to utilize them to support the maintenance and renewal strategy. CRIEPI has investigated techniques to support tools of maintenance strategies based on those data. Utility companies and CRIEPI developed several decision support tools for creating maintenance strategies for electric power equipment based on recent asset management techniques. In this paper, a concrete decision support program for overhaul planning of oil immersed transformers is presented. As one maintenance strategy for oil immersed transformers, replacement of all gaskets to avoid increasing oil leakage from main body is possible, which is called “overhaul” in this paper. Generally, such overhaul should be made at a half of life time, but its period can be shifted several years forward or backward. On the other hand, other components on a transformer, which can be replaced individually, such as a conservator or bushings, may cause oil leakage. Their replacement needs power cut of the transformer, therefore it is better to be carried out at the same time of an overhaul, if possible. And in some cases, it is better to replace these components without oil leakage preventively at the overhaul. The developed program evaluates total cost in a transformer life by considering oil leakage probability and replacement cost of incidental components, and possible overhaul period. Utility companies can examine which strategies are better with their own data.

Additional informations

Authors

Lee Yong-Jo, Malekpour Majid