EGSA Generator Load Management & Power Quality 2

Question 1

What is harmonic distortion in generator power output and why does it matter?

Accepted Answer

Distortion of the sine wave caused by non-linear loads, which can damage sensitive equipment

Answer

Harmonic distortion occurs when non-linear loads (like variable frequency drives, computers, and LED lighting) distort the generator's sine wave output. Excessive harmonics can overheat windings, damage equipment, and cause operational issues.

Question 2

What is paralleling in generator systems?

Accepted Answer

Connecting two or more generators to work together to supply a common electrical load

Answer

Paralleling allows multiple generators to share the electrical load, providing greater capacity, redundancy, and the ability to match generation to actual demand by starting or stopping units as needed.

Question 3

What conditions must be matched before paralleling two generators?

Accepted Answer

Voltage, frequency, phase angle, and phase rotation must all be matched

Answer

Before closing the paralleling breaker, both generators must match in voltage magnitude, frequency, phase angle (synchronization), and phase rotation to prevent damaging circulating currents and equipment damage.

Question 4

What is the purpose of load bank testing for generators?

Accepted Answer

To apply a controlled artificial load to verify generator performance and prevent wet stacking

Answer

Load bank testing applies a measured resistive, inductive, or combined load to verify the generator can handle its rated capacity and to burn off carbon deposits and unburned fuel (wet stacking) from underloading.

Question 5

What is 'wet stacking' in diesel generator operation?

Accepted Answer

Accumulation of unburned fuel and carbon in the exhaust system due to prolonged operation at light loads

Answer

Wet stacking occurs when a diesel generator runs at light loads (below 30% of rated capacity) for extended periods, causing incomplete combustion. Unburned fuel and carbon accumulate in the exhaust, reducing performance and potentially damaging components.

(EGSA) Electrical Generating Systems Association Certified Practice Test

(EGSA) Electrical Generating Systems Association Certified Practice Test

EGSA Generator Load Management & Power Quality 2