Generator Repair in the Power Plant: Rewinding After Winding Head Damage
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Customer & Initial Situation
A Czech energy utility commissioned the HPS-Group to repair a 12.19 MVA generator. The generator was damaged by partial discharges at the winding head, which had led to a short circuit. The goal was the complete rewinding of the stator and a comprehensive technical restoration to secure the energy supply.
Project Requirements
The following measures were defined for safe implementation at a height of 35 meters:
- Complete on-site dismantling using precise laser technology
- Rewinding using the VPI process in the HPS workshop
- Reassembly and commissioning with minimal downtime
Process in Three Phases
- Damage Analysis & Dismantling
Alignment measurement, dismantling of cooler, rectifier, and bearings, transport of the stator - Workshop: Rewinding & Testing
Cleaning, iron loss measurement, new coil production, VPI impregnation, final testing - Reassembly & Commissioning
On-site cleaning and re-impregnation, insulation and PI measurement, load test at 9 MW
Result
- Extended service life through complete rewinding
- Increased operational reliability and efficiency
- Successful handover to the customer without any complaints
Date:
15/08/2025
