EPRI ch 4

Question 1

According to load/frequency relationship, a 1 percent change in frequency will lead to what approximate magnitude load change in a 10,000 MW system?

a) 500 MW
b) 1,000 MW
c) 200 MW
d) 50 MW

Answer 1

c) 200 MW

Question 2

A governor with zero speed droop is also known as a _______ governor

a) flat frequency
b) transient loop
c) B-loaded
d) isochronous

Answer 2

d) isochronous

Question 3

The governor response rate of Steam turbines is better than a Hydro turbine?

True or False

Answer 3

False

Question 4

Control area frequency bias is:

a) control area frequency response characteristic
b) natural response of the control area
c) the AGC system bias value
d) all above

Answer 4

d) all above

Question 5

Which on of the following is not a control mode of AGC operation?

a) Flat Tie-Line Control
b) Isochronous
c) Flat Frequency Control
d) Tie-Line Bias Control

Answer 5

b) Isochronous

Question 6

Which stage of a generator’s response to a system disturbance is power flow supported primarily by the exciter system?

a) Governor response
b) AGC stage
c) Electromagnetic charge stage
d) Inertia stage

Answer 6

c) Electromagnetic charge stage

Question 7

After 2 HRs that the interconnection is operated with a frequency of 60.02 HZ, how much time error will accumulate?

a) 2.0 secs
b) 2.4 secs
c) 1.0 secs
d) 1.2 secs

Answer 7

b) 2.4 secs

Question 8

If Bias is -150MW, and frequency falls .05HZ, how many MW does control area provide?

a) -75 MW
b) 75 MW
c) -150 MW
d) 150 MW

Answer 8

b) 75 MW

Question 9

An isochronous governor has what speed droop?

a) 5%
b) 0%
c) 10%
d) 8%

Answer 9

b) 0%

Question 10

What is most susceptible to damage from abnormal frequency operation?

a) A transformer of 300MVA or greater
b) low pressure steam turbine blades
c) synchronous motor
d) induction motor

Answer 10

b) low pressure steam turbine blades

Question 11

The North American power system is divided into areas called interconnections

T or F?

Answer 11

True

Question 12

Time Error
60 HZ = no time error
under-generation = faster time error
over-generation = slower time error

T or F?

Answer 12

False

Question 13

All load can be divided into two general types; non-motor load and motor load

T or F

Answer 13

True

Question 14

Lowering the voltage will increase a motor’s speed?

T or F

Answer 14

False

Question 15

Electric generators use what to control shaft speed?

Answer 15

governor control systems

Question 16

Centrifugal ballhead governors are commonly used on older units?

T or f

Answer 16

True

Question 17

Hydro turbine and Steam turbine generators use governor control systems

T or F

Answer 17

True