EGSA Voltage Regulation and Excitation 2

Question 1

What does a negative voltage regulation value indicate about a generator's performance?

Accepted Answer

Terminal voltage rises from no-load to full-load

Answer

Terminal voltage drops from no-load to full-load

Answer

The excitation system has failed

Answer

The AVR setpoint is too low

Question 2

In a brushless excitation system, what component rectifies AC exciter output to supply DC to the main rotor field?

Accepted Answer

A rotating diode assembly mounted on the rotor shaft

Answer

Carbon brushes and slip rings

Answer

A stationary thyristor bridge

Answer

The permanent magnet pilot exciter

Question 3

A generator is operating at rated voltage with no load. When full resistive load is applied, voltage drops 8% before the AVR corrects it. This initial dip is primarily caused by:

Accepted Answer

Exciter time constant delay

Answer

AVR hunting

Answer

Generator armature resistance and reactance voltage drops

Answer

Incorrect droop setting

Question 4

What is the purpose of a derivative (rate) feedback signal in an AVR?

Accepted Answer

To improve transient response and dampen voltage oscillations

Answer

To provide steady-state voltage accuracy

Answer

To compensate for reactive droop

Answer

To measure generator frequency

Question 5

Reactive droop compensation in an AVR causes generator terminal voltage to:

Accepted Answer

Drop proportionally as reactive load increases

Answer

Rise proportionally as reactive load increases

Answer

Remain constant regardless of reactive load

Answer

Fluctuate based on power factor only

Question 6

A static excitation system differs from a brushless system primarily because it:

Accepted Answer

Supplies field current via slip rings from a stationary thyristor rectifier

Answer

Uses a pilot exciter instead of an AVR

Answer

Cannot operate without external AC power

Answer

Uses diodes instead of thyristors

Question 7

When two generators are operating in parallel and one has a higher voltage setpoint, what will happen to reactive power sharing?

Accepted Answer

The generator with higher setpoint will supply more reactive power to the bus

Answer

The generator with higher setpoint will absorb reactive power (motoring)

Answer

Both generators will share reactive power equally regardless

Answer

The system frequency will drop