Indian Institute of Technology Patna
Department of Electrical Engineering
EE480 - Power System Operation and Control
Autumn - 2016
Mid Semester Exam
19 September 2016
1. Consider the 2 bus system.
(5 marks)
x
G
1
y
2
2
y
2
x = 0.1 p.u.
SD = 1.2 + 0.9 p.u.
y = 2 p.u.
The synchronous reactance of generator is 20 %. The magnitude of voltage at bus
2 must equal 1.00 p.u.
(a) Determine the voltage that we must maintain at bus 1 in order to achieve the
above objective.
(b) Compute PG1 and QG1 .
2. Consider the 2 bus system.
( 15 marks)
x
G
1
y
2
2
y
2
x = 0.1 p.u.
SD = 1.2 + 0.9 p.u.
y = 2 p.u.
The synchronous reactance of generator is 20 %.
(a) Form YBus matrix.
(b) Find |V2 | and δ2 , if |V1 | = 1.0 p.u and δ1 = 0◦ . Use Newton- Raphson method.
Do two iterations.
(c) Find PG1 and QG1 .
3. There are two generating units in a plant. The incremental cost curves with their
minimum and maximum limits are shown here. Find the optimum dispatch and
the incremental cost for a load of 500 MW.
(5 marks)
λ (Rs/MWhr)
λ (Rs/MWhr)
250
400
150
250
100
500 P (MW)
100
500 P (MW)
4. A synchronous generator connected to an infinite bus is running overexcited with
150 %. The synchronous reactance is 120 %. The generator is delivering a real
power of 0.4 p.u. If the mechanical input is increased by 50 %, how much will be
change in PG and QG .
(5 marks)
2