Adjusting and modernization of the system converting units to synchronous capacitor operation at the Sayano-Shushenskoe hydroelectric station

Conclusions

• 1. The results of the tests conducted by Soyuztekhénergo on units Nos. 3 and 5 of the Sayano-Shushenskoe hydrostation showed that the modernized system of automatic control of water expulsion from the runner pit is operative and provides reliable control of expulsion and checking of the water level in the runner pit when converting the units to SC operation.

• 2. The capacity of the compressed-air tanks is selected with a twofold margin. The three tanks installed in the case of using the design pressure of 6.3 MPa could provide successive conversion to SC operation of at least six units.

• 3. Freeing of the runner from water occurs intensely (5–15 sec), which is provided by the high pressure in the system, correctly selected diameters of the delivery air lines, presence of a circular groove in the unloading cavity of the runner, and speed of the plug valve.

• 4. Expulsion of water from the runner pit by the nominal pressure 6.3 MPa during operation of the plug cock according to the design scheme (without an increased time of opening) should be eliminated, since the pressure under the turbine cover at the time of opening the plug cock exceeds the value used in the strength calculation of the cover. The maximum operating pressure in the expulsion system in this case should not exceed 4.5 MPa.