Repairing consequences of structural damage on turbine area
The Avče Pumped Storage Plant, located near the village of Avče in western Slovenia, is the first of its kind in the country. Completed in June 2009 and in commercial operation since April 2010, the plant was designed to contribute significantly to Slovenia's electrical grid. It pumps water from an elevation of 105 meters to 625 meters and has a 185 MW capacity.
Despite its successful operation, the plant has faced certain technical challenges that necessitated repair and maintenance. This case study will examine the plant's efficiency, the challenges faced, and the solutions implemented to maintain operational integrity.
The plant faced structural problems related to poor weld quality in the construction wall, made of structural steel. Operating pressures of about 55 bar led to a leak in the concrete structure, affecting the operational efficacy.
The turbines, manufactured by Mitsubishi Heavy, were showing signs of damage, posing a risk to the generator room located directly above the turbine. The leakage rate was measured at approximately 20.0 l/min, and it was increasing.
Euras Gel typ B was selected as the material to address the leakage. This material was injected into the concrete-metal joint near the damaged areas, forming a homogeneous sealing layer.
The gel penetrated through zones previously filled with water, significantly reducing seepage. The same material was used to supplement the pit liner zone, stopping the penetration of water into the generator area.
After the application, the leakage was reduced to zero, and the structure was stabilized. This met the investors' requirements for operational integrity.
For future preventive measures, a specialized Euras gel type g has been developed. This gel has low-abrasive fillers based on rubber flour, which would protect against the abrasion of the turbine.
The Avče Pumped Storage Plant represents a significant investment in Slovenia’s energy infrastructure but faced challenges related to structural integrity and equipment damage. Prompt and effective remediation using specialized materials has returned the facility to optimal operational standards. This case underscores the importance of stringent quality control in the construction phase and the need for ongoing maintenance to ensure long-term operational efficiency.
The Avče Pumped Storage Plant serves as an educational case for the deployment of pumped storage plants, particularly in the areas of construction quality and ongoing maintenance.