BEE BEE Bachelor of Electrical Engineering Power Systems Engineering Questions and Answers 2

Question 1

A 345 kV transmission line has a surge impedance of 400 ohms. What is the surge impedance loading (SIL) of the line?

Accepted Answer

297.6 MW

Answer

SIL equals V² divided by the surge impedance, so (345,000)² / 400 = 297.6 MW.

Question 2

In a power system, what is the primary purpose of a bus coupler breaker?

Accepted Answer

To transfer load between two bus sections without interruption

Answer

A bus coupler breaker connects two bus sections and allows load transfer between them without service interruption.

Question 3

Which type of fault in a three-phase power system typically produces the highest fault current?

Accepted Answer

Three-phase bolted fault

Answer

A three-phase bolted fault produces the highest symmetrical fault current because it has the lowest impedance path.

Question 4

What does the equal area criterion determine in power system transient stability analysis?

Accepted Answer

Whether a synchronous machine will remain in synchronism after a disturbance

Answer

The equal area criterion compares accelerating and decelerating energy areas on the power-angle curve to determine if a generator maintains synchronism.

Question 5

A generator has a transient reactance of 0.25 per unit and delivers 1.0 per unit power at unity power factor. What is the internal voltage behind transient reactance?

Accepted Answer

1.03 per unit

Answer

The internal voltage is calculated as √(Vt² + (Xd'·I)²) = √(1² + 0.25²) ≈ 1.03 per unit at unity power factor.

BEE - Bachelor of Electrical Engineering Practice Test

BEE - Bachelor of Electrical Engineering Practice Test

BEE BEE Bachelor of Electrical Engineering Power Systems Engineering Questions and Answers 2