b) A fault occurs at bus 4 of the network shown in Figure Q3. Pre-fault nodalvoltages throughout the network are of 1 p.u. and the impedance of the electricarc is neglected. Sequence impedance parameters of the generator,transmission lines, and transformer are given in Figure Q3, where X and Y arethe last two digits of your student number.jX(1) j0.1Y p.u.jX2)= j0.1Y p.u.jXko) = j0.1X p.u.V₁ = 120° p.u. V₂ = 120° p.u.(i)(ii)0jX(1) = j0.2 p.u.1 jx(2) j0.2 p.u. 2jX1(0) = j0.25 p.u.jXT(1)jXT(2)종 3j0.1X p.u. JX3(1)j0.1Y p.u.j0.1X p.u. JX3(2)j0.1Y p.u.jXT(0) j0.1X p.u. JX3(0)=j0.15 p.u.0=x = 1,jX2(1) j0.2Y p.u. V₁=1/0° p.u.jX(2(2) = j0.2Y p.u.jX2(0) = j0.3X p.u.=V3 = 120° p.u.Figure Q3. Circuit for problem 3b).For example, if your student number is c1700123, then:y = 7==jXa(r) = j0.13 p.u., jXa(z) = j0.13 p. u., and jXa(o) = j0.12 p. u.Assuming a balanced excitation, draw the positive, negative and zerosequence Thévenin equivalent circuits as seen from bus 4.4Determine the positive sequence fault current for the case when a three-phase-to-ground fault occurs at bus 4 of the network.

x=1y=7Note: reactance of element right to bus 4 is not given. Hence we will not consider that in…

A fault occurs at bus 4 of the network shown in Figure Q3. Pre-fault nodal voltages throughout the network are of 1 p.u. and the impedance of the electric arc is neglected. Sequence impedance parameters of the generator, transmission lines, and transformer are given in Figure Q3, where X and Y are the last two digits of your student number. 10.av

A fault occurs at bus 4 of the network shown in Figure Q3. Pre-fault nodal voltages throughout the network are of 1 p.u. and the impedance of the electric arc is neglected. Sequence impedance parameters of the generator, transmission lines, and transformer are given in Figure Q3, where X and Y are the last two digits of your student number. 10.av

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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Consider the system shown in the single-line diagram of Figure (3). All reactances are shown in per unit to the same base. Assume that the voltage at both sources is 1 p.u. a Find the fault current due to a bolted- three-phase short circuit at bus 3 b- Find the fault current supplied by each generator and the voltage at each of the buses 1 and 2 under fault conditions 0.06 p.u. 0.2 p.u. 0.04 p.u. 0.25 p.u. 0.2 p.u. 0.2 p.. 0.2 p.u. 0.06 p.u. 0.25 p.u. Figure (3) Single-line diagram ele ver ele 888 ele 0.06 p.u. 0.25 p.u.
The figure below shows the one-line diagram of a four- bus power system. The voltages, the scheduled real power and reactive powers, and the reactances of transmission lines are marked at this one line diagram (The voltages and reactances are in PU referred to 100 MW base. The active power P2 in MW is the last three digits (from right) of your registration number (i.e for the student that has a registration number 202112396, P2 =396). [10] Starting from an estimated voltage at bus 2, bus 3, and bus 4 equals V2 (0) = 1.15<0°, V3 = 1.15 < 0°, V4 1.1< 0°. 1- Specify the type of each bus and known & unknown quantities at each bus. 2- Find the elements of the second row of the admittance matrix (i.e. [Y21 Y22 Y23 Y24]). 3- Using Gauss-Siedal fınd the voltage at bus 2 after the first iteration. 4- Using Newton-Raphson, calculate: |- The value of real power (P2), at bus 2 after the first iteration. Il- The second element in the first row of the Jacobian matrix after the first iteration. 2 P2…
True or false 1. Three phase fault is the most commonly occurring fault than other types of faults. 2. The range of generator rotor angle for stable operation is 0°< s < 180°. 3. The infinite bus in power system is a large system with infinite voltage. 4. At value of (s= 90°) the maximum power transfer takes place. 5. Per unit system (PU) is a ratio of actual value in any units to the base or reference value in the same units.
Identify different zones of protection on the power system shown in the figure. Also, predict the operation of circuit breakers for the fault location indicated by cross mark at various locations of the power system. Generator protection Circuit breaker Low-voltage-switchgear protection Power-transformer protection High-voltage-switchgeor protection Transmission-line protection High- voltage-switchgeor protection
1.a. Separate voltage-regulating units provide voltage-ratio control under load byA. causing different impedance drops in each phase.B. combining voltages from different phases.C. having series transformers in phase with the line-to-neutral voltage.D. exciting transformers having their primaries delta-connected. 1.b. A reactor is sometimes used with an autotransformer toA. limit short-circuit current.B. increase the full-load current.C. provide increased internal impedance.D. decrease the voltage ratio.
The Y/Y connected 3-phase step-up transformer has a rating of 1200 MVA, operating at 33 kV/340 kV and 60 Hz. Its impedance is characterized solely by a reactance of 11.5 percent. Its purpose is to increase the voltage from a generating station in order to supply power to a 340 kV transmission line. Answer the following questions: a) Draw and determine the equivalent circuit of this transformer, per phase, in per-unit. b) Using the per-unit method, determine the generator terminal voltage when the high-voltage (HV) side of the transformer supplies 800 MVA at a power factor of 0.90 with a lagging angle, and the voltage is 360 kV. Hint: Select the nominal voltage as a base voltage, and the nominal power rating as a base power.
Describe the significance of fault analysis in power systems. How is fault current calculated, and how does it impact the protection and operation of a power system?
A 10 MVA three phase load is to be served by a three phase transformer at aline voltage of 13.8 kV. The supply side voltage(line-line) is 138 kV. Varioussingle phase transformers are available in the warehouse but all havewindings with voltage ratings under 100 kV and current ratings under 250 A.Is it possible to serve the load using only three single phase transformers? Ifso, specify the three phase connections and the low and high voltage ratingsof the single phase transformers.
The system values are given below. The bus 1 voltage after fault = 1.5 p.u The bus 2 voltage after fault = 1.2 p.u The line admittance between bus 1 and bus 2 (Y12 ) is = 0.8 p.u The post fault current current flow between bus 1 and 2 is ..............
(b) A 30000 kVA, 13.8 kV generator with X = 18% is connected to a bus which supplies two identical motors as shown in the Figure 2. The subtransient reactance X of each motor is 25% on a base of 6000 kVA, 7 kV. The bus voltage at the motors is 7 kV when a three phase fault occurs at the point P. For the fault specified, determine (a) the subtransient current in the fault (b) the subtransient current in breaker A and (c) the symmetrical short circuit interrupting current in the fault and in breaker A. юю DO A P 0-0 Gen. Figure 2 Motors
The nameplate on a 25-MVA, 60-Hz single-phase transformer indicates that it has a voltage rating of 8.0-kV:78-kV. A short-circuit test from the high-voltage side (low-voltage winding shortcircuited) gives readings of 4.53 kV, 321 A, and 77.5 kW. An open-circuit test is conducted fromthe low-voltage side and the corresponding instrument readings are 8.0 kV, 39.6 A, and 86.2 kW. (a) Calculate the equivalent series impedance of the transformer as referred to the high-voltageterminals.(b) Calculate the equivalent series impedance of the transformer as referred to the low-voltageterminals.(c) Making appropriate approximations, draw a T equivalent circuit for the transformer.(d) Determine the efficiency of the transformer if it is supplying rated load (unity power factor)at rated voltage at its low-voltage terminal
A short transmission line connects a step-up transformer on the source side with a series impedance of j0.5 ohms (referred to the primary) to a step-down transformer on the load side with a series impedance of 50 ohms (referred to the primary). The turn ratio of the step-up transformer is 1:10 and a no-load primary voltage of 23 (line-to-line) kV. The step-down transformer has a turn ratio of 35:2 and it has a Y-connected, balanced load of 0.490 +j 0.0816 ohms connected to its secondary side. A capacitor bank of -j0.171 ohms is added parallel to the load. Assuming an ideal transmission line, the load voltage (line-to-neutral) would be: O A. 7360 V O B. 6.2 kV O C. 12750 V O D. 4806 V O E. None of the other choices are correct