Load-Flow Study MCQs

Power System MCQs

1. The slack bus has to be a______.

a. No constraint

b. QV bus

c. PQ bus

d. PV bus

2. Providing synchronous condensers at load bus will control_________.

a. P at bus

b. Q

c. p.f

d. (b) and (c)

3. Generally in load flow solutions the load is modelled as a______.

a. Dynamically varying load

b. Constant current load

c. Constant power load

d. Constant impedance load

4. At a slack bus_________.

a. V is unknown

b. Q is unknown

c. P is known

d. δ is unknown

5. In FDLF method, the Jacobian matrix is_______.

a. A null matrix

b. Is a constant and need to be computed only once

c. To be updated at every iteration

d. To be updated one in a few iterations

6. The time taken for each iteration in NR method compared to GS method is________.

a. Depend upon the size of the power system

b. Less

c. Equal

d. More

7. Ybus  matrix is a________.

a. Unity matrix

b. Full matrix

c. Sparse matrix

d. Null matrix

8. The model used for transmission lines in load flow studies is________.

a. T-model

b. π model

c. Long-line model

d. Short-line model

9. In solution of load flow equations, if slack bus is changed______.

a. Choice of slack bus has no effect on solution of load flow equations

b. Complex voltages do not change, however line losses are affected

c. Only complex voltages will change, losses will be same

d. Complex voltages and losses will change

10. In N-R and G-S method of load flow study, the variables are respectively expressed in________.

a. Rectangular co-ordinates only

b. Polar co-ordinate only

c. polar co-ordinate and rectangular co-ordinates

d. Rectangular co-ordinates and polar co-ordinates