Pankaj Gupta, Netrapal Singh

Abstract: Faults on generator windings are more common, but many times core is also affected. The suppliers of the equipment do not guarantee satisfactory in-situ repairs of the stator core. They recommend partial or complete replacement of the core. For localized damages it may not make sense to go for entire core build up. So, the owners frequently attempt temporary solution and in-situ repairs. But the methodology of localized repair is always random. Developing efficient process for localized repairs on stator cores is essential so as to reduce the cost and outage time of the machines as well as for ensuring trouble free post repair operation. The present case study emanates from the experience gained from the field repairs of core of the stator of a hydro-generator in India. This study presents a case where the actual damage to winding insulation has been caused by deteriorated stator core laminations. The case study describes the probable causes of deterioration of winding and core, methods of locating the fault, the process adopted during the repairs and the benefits derived from the in-situ repair of core. Through the repair process, a methodology has been established for undertaking such localized repairs in stator cores.

Keywords: In-situ repair, Stator core, Hydro-generator.

Date Published: March 4, 2025
DOI: 10.11159/jmids.2025.004

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