Component protection in a pumped storage hydroelectric power plant

Pumped storage hydroelectric power plants support the security of supply by storing potential energy in the form of water when there is a surplus of electricity and making it available again when needed. They have a higher elevation reservoir and a lower elevation reservoir. When electricity is required, water from the upper reservoir flows through pipes into the lower reservoir, passing through a turbine and thereby generating electrical energy. When there is excess energy, water from the lower reservoir is pumped back into the upper reservoir.

To ensure the smooth operation of a pumped storage hydroelectric power plant, the water passes through a ball valve before it hits the turbine. This ball valve is normally only controlled when identical pressure prevails upstream and downstream of the ball valve. For the safe operation of the ball valve, filtered water is required to control the sealing plate at the seal seat when in the closed position.

A manufacturer from Baden-Württemberg, Germany, who operates several hydroelectric power plants throughout Germany, approached DANGO & DIENENTHAL with the following task.
Due to a cast iron filter that the customer had used up to that time, the valve water was partially contaminated with rust and other coarse particles. Since the metallic sealing surfaces of the ball valve must be safeguarded against all contamination, the previously used cast iron filter had to be replaced.

DANGO & DIENENTHAL manufactured a stainless-steel filter system with dimensions identical to the cast iron filter, thanks to which no major modifications were required for the on-site replacement operation.

The advantages for the customer are that the filter has a longer service life due to the rustproof material while simultaneously reliably protecting the ball valve against dirt particles.
The resulting reduction in maintenance intervals for the ball valve represents a considerable added value for the customer.