GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER-VII(NEW) EXAMINATION - SUMMER 2019
--- Content provided by FirstRanker.com ---
Subject Code:2170901
Subject Name:Inter Connected Power System
Time:02:30 PM TO 05:00 PM
Date:16/05/2019
Total Marks: 70
--- Content provided by FirstRanker.com ---
Instructions:
- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
Q.1
--- Content provided by FirstRanker.com ---
(a) What is power system stability? Classify power system stability. MARKS 03
(b) How the buses in power systems are classified? 04
(c) Explain need of load flow analysis, Derive static load flow equations. 07
Q.2
(a) When the generator bus is treated as load bus? 03
--- Content provided by FirstRanker.com ---
(b) Discuss various methods to improve steady state stability. 04
(c) The following figure shows a simple 4-bus system. 07
Line G,pu B,pu
1-2 2.0 -6.0
--- Content provided by FirstRanker.com ---
1-3 1.0 -3.0
2-3 0.66 -2.0
2-4 1.0 -3.0
3-4 2.0 -6.0
The shunt admittances at all the buses are assumed negligible.
--- Content provided by FirstRanker.com ---
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?
OR
A synchronous generator of reactance 1.2 pu is connected to an infinite bus bar (|V|=1.0 pu) through transformer and a line of total reactance of 0.5 pu. The generator no load voltage is 1.2 pu and its inertia constant is H=5 MW—s/MVA. The resistance and machine damping may be assumed negligible. The system frequency is 50 Hz. Calculate the frequency of natural oscillations if the generator is loaded to (i) 60% and (ii) 75% of its maximum power limit.
Q.3
--- Content provided by FirstRanker.com ---
(a) Explain Incremental fuel cost and penalty factor with its equation 03
(b) Explain automatic load dispatch in power system also explain the importance of regional load dispatch center. 04
(c) The incremental fuel costs for two units of a plant are given by ?1 = dF1/dPg1 =0.012Pg1+8 and ?2 = dF2/dPg2 =0.002Pg2 +9.6 07
Assuming both units are operating at all times, that total load varies from 200 to1150 MW, and that maximum and minimum loads on each unit are to be 550 and 100 MW, respectively. Find the incremental fuel cost of the plant and the allocation of load between units for the minimum cost of various total loads.
OR
--- Content provided by FirstRanker.com ---
Q.3 (a) Why bus admittance matrix is used in Gauss Seidal instead of bus impedance matrix. 03
(b) Explain speed governing mechanism for frequency control. 04
(c) Explain various techniques to improve transient stability of a power system. 07
Q.4 (a) Explain point by point method of stability in brief. 03
(b) Compare GS method of load flow study with FDLF method. 04
--- Content provided by FirstRanker.com ---
(c) Explain the step by step method of solving swing equation stating clearly the assumptions. 07
OR
Q.4 (a) Explain equal area criterion of stability. 03
(b) What is Multimachine stability? List the assumptions made in multimachine stability studies. 04
(c) For the system shown in figure, find the voltage at the receiving bus at the end of the first iteration by GS Method. Load is 2 + j0.8 pu. voltage at the sending end (slack) is 1 + j0 pu. Line admittance is 1.0 - j4.0 pu. Transformer reactance is j0.4 pu. Off nominal turns ratio is 1/1.04. 07
--- Content provided by FirstRanker.com ---
Load
Q.5 (a) Explain cascade tripping in power system. 03
(b) Explain network islanding phenomenon. 04
(c) Derive equation for B-coefficient 07
--- Content provided by FirstRanker.com ---
OR
Q.5 (a) What are the assumptions made in solving swing equation? 03
(b) Explain fully selective frequency control methods used for controlling frequency in single/two area power system. 04
(c) Explain methods used for voltage control in power systems. 07
--- Content provided by FirstRanker.com ---
This download link is referred from the post: GTU BE 2019 Summer Question Papers || Gujarat Technological University
--- Content provided by FirstRanker.com ---