6th six months

Question 1

The nominal load is:

Answer 1

Equal to the rated load

Question 2

T or F

A period of voltage instability will always result in voltage collapse.

Answer 2

False

Question 3

The critical voltage & critical MW transfer are located at the :

Answer 3

Knee of the P-V curve

Question 4

During voltage collapse prone conditions, tap changing to support secondary voltage should generally NOT be used if the secondary load is formed by:

Answer 4

Non-motor type load

Question 5

P-V curves indicate the ___ margin from voltage instability while V-Q curves indicate the____ margin from voltage stability.

Answer 5

MW/Mvar

Question 6

UVLS differs from UFLS in that:

Answer 6

UVLS is based on voltage while UFLS is based on frequency

Question 7

In which type voltage collapse does a key element outage trigger the collapse?

Answer 7

Classical Voltage collapse

Question 8

A P-V curve relates:

Answer 8

The MW transferred across a system to the voltage at the receiving end of the system.

Question 9

In a radial power system, the addition of shunt capacitors at the receiving end of the system tends to:

Answer 9

Flatten the P-V curve and increase the critical voltage.

Question 10

In which type of voltage collapse does a simultaneous stalling of large amounts of induction motor load trigger the voltage collapse?

Answer 10

Transient Voltage collapse.

Question 11

T or F

A radial power system is a power system in which generation and load areas are separated by a transmission path.

Answer 11

True

Question 12

T or F
Tap changer impact is not only due to their draw of reactive from the high side but also to their impact on the magnitude of customer load.

Answer 12

True

Question 13

T or F

Power system load is constantly changing.

Answer 13

True

Question 14

T or F
The increasing voltages due to the sudden increase in Mvar demand may cause uncontrolled tripping and rapid collapse of the area power system.

Answer 14

False

Question 15

T or F

Dynamic reactive reserves are typically carried in synchronous generators, synchronous condensers and SVC’s.

Answer 15

True

Question 16

If manual load is to be used to avoid voltage collapse which operating procedures should be performed?

Answer 16

All of the above

Question 17

T or F

As a system operator you can prevent all types of voltage collapse.

Answer 17

False

Question 18

T or F

As a last resort to avoid a voltage collapse a system operator should do nothing the load will automatically drop.

Answer 18

False

Question 19

The loss of the magnetic bonds that bind together the elements of a power system is known as:

Answer 19

All of the above; Angle stability, loss of synch, out of step.

Question 20

If a 2-pole generator’s rotor is spinning at 3601 rpm while the generator is connected to a 60Hz system, how fast is the generator’s torque angle changing?

Answer 20

6 degrees per second

Question 21

Neglecting losses, the difference between a generator’s mechanical power input & electrical power output is called:

Answer 21

Accelerating power

Question 22

T or F
Steady state instability is a slowly developing event, Transient instability is excitation systems are common cause, & oscillatory instability is a rapidly developing event.

Answer 22

False

Question 23

According to the equal area criterion for transient stability:

Answer 23

The decelerating area must at least match the accelerating area.

Question 24

T or F

A generator is angle unstable whenever its torque angle exceeds 90 degrees.

Answer 24

False

Question 25

High speed transmission protection is a benefit to angle stability because:

Answer 25

All of the above; Fault duration is reduced, accelerating time is reduced, and angle spread is reduced.

Question 26

The primary difference between an out-of-step event and a fault is:

Answer 26

The speed at which the impedance changes.

Question 27

When a power system is angle stable it has what characteristics?

Answer 27

All of the above

Question 28

T or F

The 3 classifications of angle stability are common state, oscillatory, and transient.

Answer 28

False

Question 29

T or F

Angle stability is not like voltage control in which a system operator has the time to correct voltage deviation.

Answer 29

True

Question 30

T or F

For a generator’s torque angle to change there must be accelerating power.

Answer 30

True

Question 31

T or F
Two actions available to a system operator to assist with maintaining angle stability are maintaining system voltage levels as low as possible maintaining the system impedance as high as possible.

Answer 31

False