EPRI Chapter Test - Questions And Answers (Passed!)
If a generator is producing 500MW and 200Mvar, the generator is:
✔️Ans -Lagging
87 ✔️Ans -Is the IEEE device number for a differential relay.
Can a Synchronous machine have a negative torque angle? What doies this
mean? ✔️Ans -Yes, the machine is absorbing active power.
A customer load is fed at 12o Volts. The customer's voltage is doubled while
the load magnitude stays the same. What effect does this have on the power
losses? ✔️Ans -Decreases the losses by a factor of 4.
In a DC circuit, a 100V battery is connected to both sides of a 2 ohm resistor.
What is the current through the resister and the power usage of the resister?
✔️Ans -50A/5000W
Which of the following is not a synchronizong variable? ✔️Ans -
MW flow differential.
In a typical multi-stage steam turbine, the governor control valves control
steam entry into the: ✔️Ans -High pressure turbine
The high side of a delta-wye connected transformer is connected to a power
system with 199KV L-G high side voltage. What is the voltage across the
winding of the delta transformer? ✔️Ans -345KV
Thermal limits are the direct result of? ✔️Ans -The thermal
capability of system equipment.
Reactive power flow is influenced more by system power and torque angles
than reactive power. True or False ✔️Ans -False
At what line power angle does the MW transfer across a transmission path
equal 1/2 of the path's Pmax? ✔️Ans -30 degrees
, A transmission line is rated at 1000MVA. The power flow on the line is 0MW
and 1001Mvar. Is the transmission line overloaded? ✔️Ans -Yes
The TTC limit has been determined to be 1000MW from east to west for a
particular transmission path. The transmission path operator sells 500MW of
its TTC. What is the path's ATC? ✔️Ans -500MW
A distribution line is rated for 50MVA. The line's power flow is currently
50MW and -50Mvar. The line is overloaded. True or Flase ✔️Ans -
True
Angle instability is the result of: ✔️Ans -High torque and power
angles.
If the resistance is ignored, the maximum theoretical MW flow across a
transmission line will occur at a power angle of: ✔️Ans -90
degrees.
If the resistance is ignored, the maximum theoretical Mvar flow across a line
will occur at a power angle of: ✔️Ans -180 degrees
200MW is schediuled to flow from bus X to bus Y. Transmission line A-B has a
distribution factor of 10% for this schedule. How many MW will flow on
transmission line A-B? ✔️Ans -20MW
According to the load/frequency relationship, a 1% change in frequency will
lead to what approximate magnitude of load change in a typical 10000MW
system? ✔️Ans -200MW
A governor with a 0% droop is called: ✔️Ans -An isochronous
governor
Steam turbine generators typically have better governor response than
hydroelectric generating units. True or False ✔️Ans -False
A balancing authority's frequency bias is equal to: ✔️Ans -The
balancing authority's frequency response characteristic (FRC), the natural
response of the BA, The AGC system's bias value.
If a generator is producing 500MW and 200Mvar, the generator is:
✔️Ans -Lagging
87 ✔️Ans -Is the IEEE device number for a differential relay.
Can a Synchronous machine have a negative torque angle? What doies this
mean? ✔️Ans -Yes, the machine is absorbing active power.
A customer load is fed at 12o Volts. The customer's voltage is doubled while
the load magnitude stays the same. What effect does this have on the power
losses? ✔️Ans -Decreases the losses by a factor of 4.
In a DC circuit, a 100V battery is connected to both sides of a 2 ohm resistor.
What is the current through the resister and the power usage of the resister?
✔️Ans -50A/5000W
Which of the following is not a synchronizong variable? ✔️Ans -
MW flow differential.
In a typical multi-stage steam turbine, the governor control valves control
steam entry into the: ✔️Ans -High pressure turbine
The high side of a delta-wye connected transformer is connected to a power
system with 199KV L-G high side voltage. What is the voltage across the
winding of the delta transformer? ✔️Ans -345KV
Thermal limits are the direct result of? ✔️Ans -The thermal
capability of system equipment.
Reactive power flow is influenced more by system power and torque angles
than reactive power. True or False ✔️Ans -False
At what line power angle does the MW transfer across a transmission path
equal 1/2 of the path's Pmax? ✔️Ans -30 degrees
, A transmission line is rated at 1000MVA. The power flow on the line is 0MW
and 1001Mvar. Is the transmission line overloaded? ✔️Ans -Yes
The TTC limit has been determined to be 1000MW from east to west for a
particular transmission path. The transmission path operator sells 500MW of
its TTC. What is the path's ATC? ✔️Ans -500MW
A distribution line is rated for 50MVA. The line's power flow is currently
50MW and -50Mvar. The line is overloaded. True or Flase ✔️Ans -
True
Angle instability is the result of: ✔️Ans -High torque and power
angles.
If the resistance is ignored, the maximum theoretical MW flow across a
transmission line will occur at a power angle of: ✔️Ans -90
degrees.
If the resistance is ignored, the maximum theoretical Mvar flow across a line
will occur at a power angle of: ✔️Ans -180 degrees
200MW is schediuled to flow from bus X to bus Y. Transmission line A-B has a
distribution factor of 10% for this schedule. How many MW will flow on
transmission line A-B? ✔️Ans -20MW
According to the load/frequency relationship, a 1% change in frequency will
lead to what approximate magnitude of load change in a typical 10000MW
system? ✔️Ans -200MW
A governor with a 0% droop is called: ✔️Ans -An isochronous
governor
Steam turbine generators typically have better governor response than
hydroelectric generating units. True or False ✔️Ans -False
A balancing authority's frequency bias is equal to: ✔️Ans -The
balancing authority's frequency response characteristic (FRC), the natural
response of the BA, The AGC system's bias value.
