Page 250 - Mathematical Models and Algorithms for Power System Optimization

242 Chapter 7

Fig. 7.8
Simplified block diagram of a hydro governor.

7.4.3.2 Dynamic characteristics of hydroturbine

The simulation of dynamic characteristics of the hydroturbine has taken into account the
transient process caused by the inertia of water flow in the hydroturbine and diversion pipes.
The process is also called the water hammer effect.

With the water hammer effect included, dynamic characteristics of the hydroturbine
and water diversion system thereof can be expressed by the following approximately
linear model:

1 T W p
ΔP T ¼ μ
1+ 0:5T W p
where T W —water flowing time constant; μ—opening of guide vane.

Fig. 7.9 shows the block diagram of dynamic characteristics of the hydroturbine.

Fig. 7.9

Block diagram of dynamic characteristics of the hydroturbine.

7.4.3.3 Dynamic characteristics of hydrogenerating unit
Based on Figs. 7.1, 7.8, and 7.9, the disturbance model of a hydrogenerating unit can be
obtained (shown in Fig. 7.10).
Based on the transfer functions of all blocks, the corresponding differential equation can be
obtained by adding the intermediate variables ΔM 2 and ΔN 2 into the prior block diagram