S.N.PATEL INSTITUTE OF TECHNOLOGY & RC, UMRAKH B.E. IV SEMESTER -VII

 Subject Code: 170901 Subject Name: Interconnected Power Systems

Question Bank

1 Explain cascade tripping and network islanding in brief.

2 Write a short note on Load Dispatch Centre.

3 Prove that in a YBUS matrix, the off diagonal elements are negative of the transfer admittance connected between the two buses, while the diagonal elements are sum of all admittances connected to that bus.

4 Explain the following: 1) Bus incidence matrix 2) Primitive network

5 Discuss ZBUS building algorithm. Explain all types of modifications when transmission lines are added between the buses.

6 Derive static load flow equations. Hence explain classification of buses.

7 Discuss the algorithm of load flow solution using Newton- Raphson method for all type of buses.

8 Compare NR and GS method of load flow

9 Give the algorithm with flow chart for a fast decoupled load flow solution. 10 The following figure shows a simple 4-bus system.

The shunt admittances at all the buses are assumed negligible.

1) Find YBUS assuming that the line shown dotted is not connected. 2) What modifications need to be carried out in YBUS if the line shown dotted is connected?

11 The ZBUS matrix for a certain system is given by

Find the modified bus impedance matrix if the line from bus 1 to bus 3 is Removed. Assume that impedance of line between bus 1 and bus 3 is 0.25 Ohm

12 Write short note on unit commitment.

13 Derive the criterion for economic distribution of load between different units of a plant when transmission losses are neglected.

14 Derive the expression for B-coefficients in case of two generating plants connected to an arbitrary number of loads through a transmission network.

15 Figure shows the one line diagram of simple three bus power system with generator at buses 1 & 3. The magnitude of voltage at bus 1 is adjusted to 1.05 pu. Voltage magnitude at bus 3 is fixed at 1.04 pu with real power generation of 200 MW. A load consisting of 400 MW and 250 Mvar is taken from bus 2. Line impedances are marked in pu on 100 MVA base, and line charging susceptances are neglected. Obtain Gauss-siedel power flow solution for 2 iteration.