Power System-II 2018 Question Paper — Government College of Engineeri…

The 2018 Power System-II previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.

Instructions

Q1. Derive an expression for singular transformation technique, by using the same formulate the Y-bus of the network shown in Fig.(1) $Z_{01} = 0.4\text{ P}_u$, $Z_{12} = 0.02\text{ P}_u$, $Z_{23} = 0.1\text{ P}_u$, $Z_{34} = 0.07\text{ P}_u$, $Z_{45} = 0.03\text{ P}_u$, $Z_{05} = 0.05\text{ P}_u$ For the network shown in Fig. (1): [20 marks]
Q2. The following is the system data for a load flow solution The line admittances: | Line | Admittance | |---|---| | 1-2 | -j5 | | 1-3 | -j5 | | 1-4 | -j5 | | 2-3 | -j10 | | 3-4 | -j10 | The schedule of active and reactive powers: | Bus | P | Q | V | Remarks | |---|---|---|---|---| | 1 | - | - | 1+j0.0 | slack bus | | 2 | 1 | 0.1 | - | PQ bus | | 3 | 3.5 | 0.3 | - | PQ bus | | 4 | 1 | 0.2 | - | PQ bus | Find the voltages at the end of first iteration using Gauss-Seildel method. [20 marks]
Q3. a) Use NR method to solve the equations $\sin x = y - 1.32$ $\cos y = x - 0.85$ b) Distinguish between steady state, transient and dynamic stability. Derive power angle equation. Define transfer reactance. [20 marks]
Q4. a) A 2-pole, 50Hz, 11.5KV, turbo generator has a rating of 100MW, power factor 0.85 lagging. Its rotor has moment of inertia of $8800\text{ kg.m}^2$. Calculate its inertia constant in MJ/MVA and its momentum in MJ-Sec/elect. deg. b) How can the transient stability of a system be improved? Discuss the traditional as well as new approaches to the problem. [20 marks]

Q5. A system consists of two plants connected by a transmission line and a load is at power plant 2 as shown in Fig.(2). Data for the loss equation consists of the information that 200MW transmitted form plant 1 to the load results in a transmission loss of 20MW. Find the optimum generation schedule considering transmission losses to supply a load of 204.41MW. Also evaluate the amount of financial losses are not co-ordinated. Assume that the incremental fuel cost characteristics of plant 1 and 2 are given by $\frac{dF_1}{dP_{g_1}} = 0.025\,P_{g_1} + 14\text{ Rs/MWh}$ $\frac{dF_2}{dP_{g_2}} = 0.05\,P_{g_2} + 16\text{ Rs/MWh}$ For the system shown in Fig. (2): [20 marks]
Q6. Explain the power system reliability by considering the Bath-tub curve, outage and state space diagram [20 marks]
Q7. a) Explain the maintenance scheduling of optimal system operation b) Derive the expression of derivation of transmission loss formula. [20 marks]
Q8. a) A surge of 15 V magnitude travels along a cable towards its junction with an overhead line. The inductance and capacitance of a cable and overhead line are respectively $0.3\text{ mH}$, $0.4\text{ }\mu\text{F}$ and $1.5\text{ mH}$, $0.012\text{ }\mu\text{F}$ per km. Find the voltage rise at the junction due to the surge. b) Explain the variation of current and voltage on an overhead line when one end of the line is i) Short circuited, and ii) Open-circuited and at the other end a source of constant e.m.f. V is switched in. [20 marks]