EGSA Power Generation Equipment 5

Question 1

What does a generator's voltage regulator sense to provide reactive power load sharing between paralleled units?

Accepted Answer

Reactive power output (kVAR) via a cross-current compensation circuit

Answer

Cross-current compensation (reactive droop) allows AVRs to sense and adjust excitation based on reactive current, ensuring proportional kVAR sharing between paralleled generators.

Question 2

Which insulation class designation indicates that a generator winding can operate at a maximum temperature of 155°C?

Accepted Answer

Class F

Answer

Class F insulation has a maximum continuous operating temperature of 155°C (including a 40°C ambient and temperature rise allowance).

Question 3

What is the significance of the generator's Telephone Influence Factor (TIF) rating?

Accepted Answer

Quantifies harmonic content weighted by telephone interference sensitivity

Answer

TIF is a weighted harmonic factor that quantifies how much a generator's voltage waveform could induce interference into nearby telephone circuits.

Question 4

What condition triggers a 'reverse power' (anti-motoring) relay on a generator paralleled to the utility?

Accepted Answer

Generator begins drawing real power from the bus instead of supplying it

Answer

A reverse power relay detects when real power flow reverses direction and the engine is being motored by the bus, protecting the prime mover from damage.

Question 5

In a critical facility using an automatic transfer switch (ATS), what is the 'time delay to transfer' (TDT) setting used for?

Accepted Answer

Prevent transfer for momentary utility outages shorter than the set delay

Answer

The time delay to transfer prevents nuisance transfers for brief utility interruptions, only initiating generator start and transfer if the outage persists beyond the TDT setting.

(EGSA) Electrical Generating Systems Association Certified Practice Test

(EGSA) Electrical Generating Systems Association Certified Practice Test

EGSA Power Generation Equipment 5