+ 359 2 4748 800 info@gcr.bg

Reconstruction of the existing hydroautomatics of a spherical valve DN 400, PN 30 at Mala Tsarkva HPP


  • duration:
    january 2020 – july 2020
  • Budget:
    27 500 BGN
    eurofluid hydraulik, kazanluk, Bulgaria

Project site

Mala Tsarkva HPP is a derivation HPP located in the Rila Mountains, part of the Rila Waterworks of the city of Sofia. Gross fall 306 meters. The plant has two horizontal hydro units in operation since 1933 and 1941 with an installed capacity of 7.7 MW. Average annual production: 37,400,000 kW / h. The turbines are Pelton type, manufactured by VOITH – Austria. The plant is connected to a medium voltage network – 20 KV.

Project scope

Design of a new drive and hydraulic automation for control of the spherical valve. The project includes the replacement of the existing hydraulic cylinder for opening and closing the spherical valve. The existing cylinder is driven by water from the penstock. The existing kinematic unit (rack and pinion sector) of the old drive has been removed and a new support structure has been installed in its place, which is fixed to the housing of the spherical valve. A hydraulic cylinder is hinged to the new support structure, and an arm is fixed to the neck of the rotating body of the valve. The cylinder is controlled by a hydraulic station in a logical sequence of processes set by the turbine regulator controller.

The new equipment was installed, functional tests were performed and the spherical valve was put into regular operation


Reconstruction of the drive of the spherical valve and bringing it in line with the new trends in the drive of the shut-off equipment in front of the turbines of the hydro units.

Reconstruction of the drive allows control of the spherical valve in the conditions of a “black start” and the possibility for full automation of the processes in the future introduction of a control system in HPP.