EPRI ch 5 Flashcards
What is the MVar production of a 50 MVar shunt capacitor that is energized at 90% of its normal voltage?
a) 40.5
b) 45
c) 55.6
d) 61.7
a) 40.5
A 5% reduction in the customer’s voltage will result in approximately what reduction in load magnitude?
a) 2%
b) 3%
c) 5%
d) 10%
b) 3%
What causes a transformer to be overexcited?
a) high voltage
b) low frequency
c) both
d) all above
d) all above
How many Mvars per mile are produced for a 345kV line?
a) 1/3
b) 3/4
c) 2.0
d) 5.0
b) 3/4
At which voltage will a 345kV line produce the most reactive power?
a) 345kV
b) 340kV
c) 350kV
d) 360kV
d) 360kV
50 ohms of inductive reactance, 25 ohms of series capacitors. What is the percentage or series compensation?
a) 25%
b) 40%
c) 50%
d) 80%
c) 50%
The point at which the Mvar from the line’s capacitance provides exactly the Mvar the line needs to support its voltage is known as:
a) Surge Impedance Limit
b) Angle Stability Limit
c) Voltage Stability Limit
d) Themal Limit
a) Surge Impedance Limit
How many Mvars per mile are produced for a 500kV line?
a) 1/3
b) 3/4
c) 2.0
d) 5.0
c) 2.0
Given a purely inductive load that can be said about the MVA the load draws?
a) draws only MW
b) draws only Mvar
c) load cannot exceed 100 MVA
d) load cannot exceed 1,000 MVA
d) draws only Mvar
Generators with spare Mvars is always a source of dynamic reactive reserve
T or F
False
There are two types of power produced by the system generators: active power (MW) and reactive power (Mvar)
T or F
True
Some common causes of low voltage include
a) heavy power transfers
b) motor stalling
c) reactive equipment outages
d) all above
d) all above
Generators are the primary means of controlling a power systems voltages?
T or F
True
Excessively high voltages can be less dangerous than low voltages?
T or F
False
There are three general time frames for overcharge. They are:
a) long term, short term, transient
b) transient, long term, peak
c) peak, short term, long term
d) none above
a) long term, short term, transient
