LFC: Single Area Control

Q. Given a single area with two generating units.

Unit	Rating	Speed drop R (per unit on unit base)
1	400	0.04
2	800	0.05

The units share a load of $P_1=200MW,P_2=500MW$. The units are operating in parallel to share a load of 700 MW at 50 Hz frequency. The load is increased by 130 MW with B = 0, The value of new frequency caused by steady state frequency deviation is _______ Hz.

1. 49.75

Q. Consider a power system with three identical generators. The transmission losses are negligible. One generator (G1) has a speed governor which maintains its speed constant at the rated value while the other generators (G2 and G3) have governors with a droops of 5%. If the load of the system is increased, then in steady state.

1. Generation of G2 adn G3 is increased equally while generation of G1 is unchanged.
2. Generation of G1 alone is increased while generation of G2 and G3 is unchanged.
3. Generation of G1, G2 and G3 is increased equally.
4. Generation of G1, G2 and G3 is increased in the ratio 0.5 : 25 : 0.25