Renewal of maintenance-intensive SF6 circuit-breakers (72.5 kV) for the direct converter of pump-storage plants A and D. Additionally, the replacement of generator breaker switchgear for the start-up converters in the North and South.


Challenges

• Further use of existing breaker cells, connection points and current cables for the inverters
• Installation of two new units under limited space conditions for the starting inverters
• Control of the recovery voltage (peak 55 kVp)

Solution

• In total 8 vacuum circuit-breakers type 3AH4 (24 kV, 2500 A, 40 kA) have been installed including spare circuit-breakers for the inverters.
• Installation of two VB1 generator switchgears with totally 7 vacuum circuit-breakers type 3AH4 (24 kV, 2500 A, 40 kA) under limited space conditions.

The Goldisthal pumped-storage Station is a pumped-storage power plant in the Thüringer Mountains at the upper run of the river Schwarza in Goldisthal, Germany. It was constructed between 1997 and 2004. It has an installed capacity of 1,060 megawatts (1,420,000 hp), making it the largest hydroelectric power plant in Germany and one of the largest in Europe.