publication . Bachelor thesis . 2013

Improved Governing of Kaplan Turbine Hydropower Plants Operating Island Grids

Gustafsson, Martin;
Open Access English
  • Published: 01 Jan 2013
  • Publisher: KTH, Reglerteknik
  • Country: Sweden
Abstract
To reduce the consequences of a major fault in the electric power grid, functioning parts of the grid can be divided into smaller grid islands. The grid islands are operated isolated from the power network, which places new demands on a faster frequency regulation. This thesis investigates a Kaplan turbine hydropower plant operating an island grid. The Kaplan turbine has two control signals, the wicket gate and the turbine blade positions, controlling the mechanical power. The inputs are combined to achieve maximum turbine efficiency at all operating points. In relative terms, the wicket gate has a fast dynamic but small effect on the mechanical power, while the...
Related Organizations
Download from

1 Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Theory of Kaplan Turbine Hydropower Plant 5 2.1 Kaplan Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.1 Wicket gates and turbine blades . . . . . . . . . . . . . . . . 7 2.1.2 Servos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.3 Combination Unit . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Penstock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 Per Unit - pu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Frequency Control 11 3.1 PID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2 Droop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.3 Anti-windup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.4 Regulation criterion . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4 Control Strategies 17 4.1 Combination Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 Inverted Combination Anti-windup . . . . . . . . . . . . . . . . . . . 20

5 Simulation Model 23 5.1 Governor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2 Servos and Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.3 Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.4 Generator and Load . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6 Analysis Method 27 6.1 Time Domain Simulation . . . . . . . . . . . . . . . . . . . . . . . . 27 6.1.1 Stationary Behaviour study . . . . . . . . . . . . . . . . . . . 28 6.1.2 Efficiency Losses . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.3 Load Disturbance Simulations . . . . . . . . . . . . . . . . . . 30 6.1.4 Inverted Combination Anti-windup . . . . . . . . . . . . . . . 31 6.2 Controllability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 31

7 Results 33 7.1 Stationary Behaviour Study . . . . . . . . . . . . . . . . . . . . . . . 33 7.1.1 Turbine blade position as a function of wicket gate position and mechanical power α = f (γ, Pm) . . . . . . . . . . . . . . 33 7.1.2 Mechanical power as a function of wicket gate and turbine blade positions Pm = f (γ, α) . . . . . . . . . . . . . . . . . . 34 7.2 Efficiency Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 7.2.1 Efficiency as a function of electric power and combination offset η = f (Pm, offset) . . . . . . . . . . . . . . . . . . . . . 35 7.2.2 Efficiency, wicket gate and turbine blade position relationship 36 7.3 Load Disturbances . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 7.3.1 Maximum Load Step Disturbance . . . . . . . . . . . . . . . 37 7.3.2 Step Responses . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7.4 Inverted Combination Anti-windup. . . . . . . . . . . . . . . . . . . 41 P P P [1] Svensk Energi, Vattenkraft, Utgåva 7, September 2001

[13] L.M. Hovey, Optimum Adjustment of Hydro Governors on Manitoba Hydro System, AIEE Trans., Vol. 81, Part Ill, pp. 581-587, Dec. 1962.F.R.

[14] Schleif and A.B. Wilbor, The Coordination of Hydraulic Turbine governors for Power System Operation, IEEE Trans., Vol. PAS-85, pp. 750-758, July 1966.

[15] S. Hagihara, H. Yokota, K. Goda, K. Isobe, Stability of a Hydraulic Turbine Generating Unit Controlled by P.I.D. Governor, IEEE Transactions on Power Apparatus and Systems, 1979, Vol.PAS-98(6), pp.2294-2298

[16] L. Ljung, T. Glad, Modellbygge och simulering, ISBN 9789144024431, 2009, pp 216-218

Powered by OpenAIRE Research Graph
Any information missing or wrong?Report an Issue