WorksheetsEE8501 PSA Revision
Total questions: 50
Worksheet time: 50mins
What is the per unit impedance Z(Pu) in a power system
( Z * (MVA)B) / (KVB)2
( 1000 * (KV)B) / √3 IB
( Z * (KV)2 ) / (MVA)B
None of these
Which among the following assumptions are made in the reactance diagram?
The neutral reactance are neglected
Static loads are neglected.
The capacitance of the transmission lines are neglected
All of these
The per unit impedance of a circuit element is 0.30. If the base kV and base MVA are 0.5, then the new value of the per unit impedance of the circuit element will be
0.30
0.60
0.0030
0.0060
The per unit value of a 2 ohm resistor at 100 MVA and 10 kV base voltage is
4 pu
2 pu
0.5 pu
0.2 pu
Per unit of any quantity is defined as
actual value of quantity /base value of quantity in same units
actual value of quantity /base value of quantity in different units
base value of quantity /actual value of quantity in same units
base value of quantity /actual value of quantity in different units
Advantage/s of per unit system as compare to absolute system?
only one equation is required
calculation time is less
Memory required is less
No units for any quantity
all of the above
A transmission line has (2 + j4)Ω impedance, 100 MVA and base voltage is 10 KV. Find the per unit impedance value of transmission line?
(2 + j4 ) pu
(1 + j2 ) pu
(4 + j8 ) pu
(0.5 + j1 ) pu
A generator has a rating of 10 MVA, 5 kV has a reactance of 0.02 pu. Find the reactance at a new base values of 50 MVA, 10 kV?
0.02
0.025
0.05
0.25
Length of short transmission line is up to
80 km
250 km
40 km
any of the above
What is the formula to calculate the (kV)B on the LT section?
(kV)B on HT section * (HT voltage rating) / (LT voltage rating)
(kV)B on LT section * (HT voltage rating) / (LT voltage rating)
(kV)B on HT section * (LT voltage rating) / (HT voltage rating)
(kV)B on LT section * (LT voltage rating) / (HT voltage rating)
What is the formula to calculate the (kV)B on the HT section?
(kV)B on HT section * (HT voltage rating) / (LT voltage rating)
(kV)B on LT section * (HT voltage rating) / (LT voltage rating)
(kV)B on HT section * (LT voltage rating) / (HT voltage rating)
(kV)B on LT section * (LT voltage rating) / (HT voltage rating)
In impedance diagram different power system elements are represented by symbols.
True
False
Which among these is the equivalent circuit for the synchronous motor?
Only a
Only b
Only c
Only d
What is the simplified diagram called, after omitting all resistances, static loads, capacitance of the transmission lines and magnetizing circuit of the transformer?
Single line diagram
Resistance diagram
Reactance diagram
Both (a) and (b)
Which is the state with the highest energy consumption in India?
Andhra Pradesh
Gujarat
Maharashtra
Tamil Nadu
Which of the following method may be used to inject reactive power in the transmission line?
Series capacitor
Series capacitors
Synchronous capacitors
All the above
The power plant which has minimum running cost:
Thermal plant
Hydro plant
Coal power plant
Nuclear power plant
What is the installed power capacity in India?
371 GW
371 MW
371 KW
All the above
What is the installed power capacity in India?
371 GW
371 MW
371 KW
All the above
In load flow studies of a power system, a voltage control bus is specified by
Real power and reactive power
Reactive power and voltage magnitude
Voltage and voltage phase angle
Real power and voltage magnitude
In power system, the maximum number of buses are
Generator buses
Load buses
Slack buses
P-V buses
In power system, if a voltage controlled bus is treated as a load bus then which one of the following limits would be violated ?
Voltage
Active power
Reactive power
Phase angle
In a load flow analysis of a power system, the load connected at a bus is represented as
Constant current drawn from the bus
Constant impedance connected at the bus
Voltage and frequency dependent sources at the bus
Constant real and reactive power drawn from the bus
The voltage of a particular bus can be controlled by controlling the
Active power of the bus
Reactive power of the bus
Phase angle
All of the above
Gauss-Seidel interative method can be used for solving a set of
Linear differential equations only
Linear algebraic equations only
Both linear and nonlinear algebraic equations
Both linear and nonlinear algebraic differential equations
Compared to Gauss-Seidel method, Newton-Raphson method takes
Less number of iterations and more time per iteration
Less number of iterations and less time per iteration
More number of iterations and more time per iteration
More number of iterations and less time per iteration
Regulation transformers are used in power systems for control of
Voltage
Power factor
Power flow
All of the above
In a load flow study a PV bus is treated as a PQ bus when
Voltage limit is violated
Active power limit is violated
Phase angle is high
Reactive power limit is violated
Which among the following quantities are to be determined in voltage controlled bus?
P and Q
Q and |V|
|V| and δ
Q and δ
Which among theses quantities are to be determined in slack bus?
P and Q
Q and |V|
|V| and δ
Q and δ
Which among the following buses constitute the maximum number in a power system?
Slack bus
P Q bus
P V bus
None of these
Which among the following quantities are specified at the generator bus?
P and Q
P and |V|
Q and |V|
P and δ
Why are load flow studies carried out?
To study of stability of the system
For fault calculations
For planning the power system
All of these
What method is used for load flow studies?
Y bus
Z bus
All of the above
None of these
What method is used to find fault analysis?
Y bus
Z bus
All of the above
None of these
What method is used to find fault analysis?
Y bus
Z bus
All of the above
None of these
What percentage of buses in the power system are generator buses?
5 %
25 %
75 %
10 %
The per unit impedance of a circuit element is 0.30. If the base kV and base MVA are 0.5, then the new value of the per unit impedance of the circuit element will be
0.30
0.60
0.0030
0.0060
The per unit value of a 2 ohm resistor at 100 MVA and 10 kV base voltage is
4 pu
2 pu
0.5 pu
0.2 pu
A generator has a rating of 10 MVA, 5 kV has a reactance of 0.02 pu. Find the reactance at a new base values of 50 MVA, 10 kV?
0.02
0.025
0.05
0.25
Which among theses quantities are to be determined in slack bus?
P and Q
Q and |V|
|V| and δ
Q and δ
Which among the following quantities are specified at the generator bus?
P and |V|
Q and |V|
|V| and δ
Q and δ
For a given base voltage and base volt ampere, per unit impedance value of an element is X. What will be the per unit impedance value of this element when the voltage and volt ampere base are both doubled?
0.5X
2X
3X
4X
Which of the following statement is true?
a = 0.5 – j 0.866
a = 0.5 + j 0.866
a4 = - a
1+a+a2 = 0
What is the value of zero sequence impedance in line to line faults?
Z0 = 1
Z0 = ∞
Z0 = 3 Zn
Z0 = 0
What is the range of ‘δ’ for stable operation?
0° < δ < 45°
45° < δ < 90°
0° < δ < 90°
0° < δ < 120°
At what value of ‘δ’ the maximum power transfer takes place?
45 °
90°
180°
120°
What kind of differential equation is swing equation?
Linear second order
Non linear first order
Linear first order
Non linear second order
Which among the following methods is used for improving the system stability?
Increasing the system voltage
Reducing the transfer reactance
Using high speed circuit breaker
All of these
What is power system stability?
The ability of the power system to regain the state of operating equilibrium point when the system is subjected to any disturbances.
The maximum power flow possible through a particular component connected in the power system.
It is a phenomenon in which a power system losses its operating equilibrium when subjected to large disturbances.
All of these
