Operating stability of hydroelectric stations with downstream surge tanks

Abstract

1. Hydraulic investigations of T-shaped forks made it possible to refine the character of head losses in the junction of the tank with the conduits. The use of the dependences obtained in calculating the stability of the regimes of a hydroelectric station just due to a more accurate consideration of the effect of the velocity head in the base of the surge tank permits substantiating a considerable decrease of the critical area of downstream surge tanks. 2. In calculations of the critical area of downstream surge tanks it is necessary to include in total head losses the velocity head in the outlet section of the outflow channel. In this case the value of the critical area decreases. 3. The proposed method of analyzing the stability of HES regimes with the use of the Routh algebraic criterion permits relating the adjustment parameters of the ARS, turbine characteristics, and power system among themselves to the area of the surge tank and solving the problem of stability in the complex. 4. At hydrostations with short outflow pressure conduits it is advisable to take small, up to 10% of the Thoma critical, cross-sectional areas of the surge pipe of a surge tank with an expansion chamber. This makes it possible, on one hand, to reduce the amount of works on the tank and, on the other, to provide stable regimes of the hydrostations while retaining the adjustment parameters of the ARS.