# Power System MCQ Part 3

Power System MCQ Part 3

## When all three phases are short circuited, electric current through system is

When all three phases are short-circuited, the electric current through the system is:

1. Zero
2. Low but not zero
3. Very high
4. None of these

## The operator a rotates vector in anticlockwise direction by degrees of

The operator a rotates vector in anticlockwise direction by degrees of:

1. 60°
2. 90°
3. 120°
4. 180°

## If Z1 and Z2 are positive and negative sequence impedances in a synchronous generator, then which of the following statements is correct

If Z1 and Z2 are positive and negative sequence impedances in a synchronous generator, then which of the following statements is correct:

1. Z1 < Z2
2. Z1 > Z2
3. Z1 = Z2
4. Z1 < 10Z2

Correct answer: 2. Z1 > Z2

## Current limiting reactors in electric power system have

Current limiting reactors in electric power system have:

1. Large reactance and large resistance
2. Large resistance and low reactance
3. Large reactance and low resistance
4. None of these

Correct answer: 3. Large reactance and low resistance

## Zero sequence component in 3 phase voltage of delta connection is

Zero sequence component in 3 phase voltage of delta connection is:

1. Zero
2. Line voltage
3. Line voltage/√3
4. √3 * Line voltage