[Total No. of Questions - 8]
[Total No. of Printed Pages - 2]


B.E. VIIIth Semester Examination
BE-VIII/6(A)
211420
Electrical Engineering
Course No. EE - 802
Power System-III
New Syllabus
Time Allowed - 3 Hours Maximum Marks - 100

Note: Attempt any five questions, all questions carry equal marks.
    1. How do you form bus admittance matrix [YBUS], by inspection? Explain.
    2. An admittance diagram for a two bus network is as shown. Find [YBUS]. Also draw impedance diagram and by inverting [YBUS], obtain v1 + v2.
    1. A 3 Bus n/w is as shown. The series impedance and shunt admittance of each line are 0.026 + j0.11 p.u and j0.04 p.u respectively. The specifications are shown in table:


      For bus 2 the minimum and max reactive power limits are 0 and 0.8 p.u:
      1. Form [YBUS]
      2. Find P2o, Q2o, P3o, Q3o
      3. Find [Jo]
    2. Give the flowchart for load studies using Newton-Raphson method. How does the method get modified to account for PV buses?

  3. Explain in detail methods of improving power system stability.
    1. List the factors determing the stability limit.
    2. Find the max. steady state power when:
      1. Static capacitor is connected
      2. Replaced by inductive reactor of same reactance. What will be the value of P and Q in both cases if del = 30o.
    1. Give mathematical derivation of swing equation.
    2. An alternator with X'd = 0.1 p.u. is delivering power of 0.8 p.u. at a termial voltage of 1.05 p.u. The inertia constant is 4 MJ/MVA. This alternator is suddenly synchronised to an infinite bus through a transformer of reactance of 0.1 p.u. and a double circuit transmission line of 0.4 p.u. reactance each. Assuming the infinite bus voltage to be 1.0 p.u, determine swing equation.
    1. Describe different types of reactive power compensators.
    2. Establish the relationship between the incremental changes of Q, P and V in a load node.
    1. Define surge impedance with reference to transmission line and deduce from 1st principles and expression for it.
    2. A generator with a generated voltage ER is connected across the lossless transmission line of length x metres, the load across this line is 1/4th of the surge impedance of the line. The generator surge impedance is 1/2 of the surge impedance of line. Draw the Bewley's Lattice diagram.

  4. Write short notes on:
    1. Limitations of Newton's Raphson method.
    2. Decoupled load flow analysis.
    3. Application of the swing curve.
    4. Bewley's lattice





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