Q6: A five-bus network has generators at buses 1 and 3 rated 270 and 225 MVA, respectively. The generator sub-transient reactances plus the reactances of the transformers connecting them to the buses are each 0.3 pu on the generator rating as base. The turns ratios of the transformers are such that the voltage base in each generator circuit is equal to the voltage rating of the generator. Line impedances in pu on a 100 MVA system base are shown in Fig. below. All resistances are neglected. Using the bus impedance matrix for the network which includes the generator and transformer reactances, find the sub-transient current in a three phase fault at bus 4 and the current coming to the faulted bus over each line. Prefault current is to be neglected and all voltages are assumed to be 1 pu before the fault occurs. (2) j0.126 1.0/0° j0.168 ll 1.0/0 ll j0.1333 ll j0.1111 ll 5 j0.126 j0.210 ell j0.252 4 j0.336 hellte

Q6: A five-bus network has generators at buses 1 and 3 rated 270 and 225 MVA, respectively. The generator sub-transient reactances plus the reactances of the transformers connecting them to the buses are each 0.3 pu on the generator rating as base. The turns ratios of the transformers are such that the voltage base in each generator circuit is equal to the voltage rating of the generator. Line impedances in pu on a 100 MVA system base are shown in Fig. below. All resistances are neglected. Using the bus impedance matrix for the network which includes the generator and transformer reactances, find the sub-transient current in a three phase fault at bus 4 and the current coming to the faulted bus over each line. Prefault current is to be neglected and all voltages are assumed to be 1 pu before the fault occurs. (2) j0.126 1.0/0° j0.168 ll 1.0/0 ll j0.1333 ll j0.1111 ll 5 j0.126 j0.210 ell j0.252 4 j0.336 hellte

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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Q2\ The one-line diagram of a simple power system is shown in figure below. All impedances are expressed in per unit (pu) on a common MVA base. All resistances and shunt capacitances are neglected. The generators are operating on no load at their rated voltage. A three-phase fault occurs at bus 1 through a fault impedance of Zf = j0.08 per unit. Using Thevenin's theorem obtain the impedance to the point of fault and the fault current in per unit. Determine the bus voltages and line currents of generators during fault. X₁ = = 0.1 XT-0.1 3 1 to ojo XL=0.2 2 040 X₁ = 0.1
Needs Complete solution with 100 % accuracy.
Problem 2 Two shunt generators A and B operate in parallel and their load characteristics maybe taken as straight lines. The voltage falls from 240V at no load to 200V at200A, while that of B falls from 245V at no load to 220V at 150A. Determine the bus bar voltage when supplying 66.9KW load. How is the load divided between two generators?
2.2. The figure below shows a radial transmission system with a generator having a per-unit voltage of 1.3 at an angle of 9 degree p.u. The load demand is 47MW at a power factor of 0.96lagging. Use the nameplate values of Transformer 2 as base values and calculate the following: Correct answers to three decimal places : 25..Per unit impedance of transformer and it's angle 26.Per unit voltage of the line and its angle 27.Per unit impedance of the line and its angle. And Reactance of the transmission line when the load consumes full-load (Ω).
A network consisting of a set of generator and load buses is to be modeled with a DC power flow, for the sake of conducting a contingency analysis. The initial flows calculated with the DC power flow give the following information: f°2-4 = - 65.3 MW and fº4-5 = 13.6 MW. The following values of LODF and PTDF factors are given: PTDF54,2-4 = -0.2609, LODF2-4,4-5 = -0.6087. Calculate the contingency flow on line 2-4 due to outage of line 4-5. Select one: O a. -75.5MW O b. None of these O c. -68.85MW O d. -73.58MW O e. 75.5MW O f. -61.75MW
Discussion : 1- What are the advantages and disadvantages of this test ? 2- Why it's imporctical carry out actual load test on large rating transformers ? 3- What will be the current in the primary windings? i) When secondaries are not loaded ? ii) When secondaries are loaded ?
need detailed solution and complete steps for the parts 4,5 and 6.
10. A three-phase transformer consists of a bank of single-phase transformers connected to form a Dd0 connection. A fault on one of the transformers causes it to be removed from the circuit, and the remaining two transformers are connected in an open-delta (V-V) connection. Show that the capacity of the open-delta connected transformers is 58% of the delta-connected transformers.
The _____________________ of transformers are neglected to draw the reactance diagram. -Series conductance -Series reactance -Static Loads -Shunt branches
A synchronous generator is connected through a transformer and a transmission line to synchronous motor. The rated voltage and apparent power of the generator serve as the base quantities for this power system. On the system base, the per-unit sub transient reactance of the generator and the motor are 0.15 and 0.40 respectively, the series reactance of the transformer is 0.10, and the series reactance of the transmission line is 0.20. All resistances may be ignored. The generator is supplying rated apparent power and voltage at a power factor of 0.85 lagging when a three-phase synchronous fault occurs at the terminals of the motor. Find the per-unit sub transient current at the fault, in the generator, and in the motor.
Q6