Q7: Generators G and G2 are identical and rated 11 kV, 20 MVA and have a transient reactance of 0.25 pu at own MVA base. The transformers T and T2 are also identical and are rated 11:66 kV, 5 MVA and have a reactance of 0.06 pu to their own MVA base. The line is 50 km long; each conductor has a reactance of 0.848 ohm per km. The three phase fault is assumed at F, 20 km from generator G, as shown in Fig. below. Find the short circuit current. (G) (G2) F T2

Q7: Generators G and G2 are identical and rated 11 kV, 20 MVA and have a transient reactance of 0.25 pu at own MVA base. The transformers T and T2 are also identical and are rated 11:66 kV, 5 MVA and have a reactance of 0.06 pu to their own MVA base. The line is 50 km long; each conductor has a reactance of 0.848 ohm per km. The three phase fault is assumed at F, 20 km from generator G, as shown in Fig. below. Find the short circuit current. (G) (G2) F T2

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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t Figure below shows a power system where load at bus 5 is fed by generators at bus 1 and bus 4. The generators are rated at 100MVA; 11 KV with subtransient reactance of 25%. The transformers are rated each 100 MVA, 11/112 KV and have a leakage reactance of 8%. The lines have an inductance of 1 mH/phase/km. Line L1 is 100 km long while lines L2 and L3 are each of 50 km in length. Load For a 3-phase fault at bus 5, the fault current is equal to 2530A. What the value of the change in the fault current if the value of the base voltage is changed to .10 kV (i.e. new value/old value) 1.0426 0.9833 1.0245 1.0166 0.9751 1
powe system Q8
"As per the standards used in power system, even harmonics are limited to 25 percent of the odd harmonic limits" True False
A generator feeds power to an infinite bus through a double circuit transmission line. A3 phase fault occurs at the middle point of one of the lines. The infinite bus voltage is 1 pu, the transient internal voltage of the generator is 1.1 pu and the equivalent transfer admittance during fault is 0.8 pu. The 100 MVA generator has an inertia constant of 5MJ/MVA and it was delivering 1.0 pu power prior of the fault with rotor power angle of 30 °. The system frequency is 50 Hz. The initial accelerating power (in pu) will be
urgent required.
A 12 MVA, 132/6.6 kV, transformer having a reactance of 0.15 pu is fed from an infinite bus. The transformer feeds two motor each 6 MVA, 6.6 kV. Each motors has a transient reactance of 0.14 pu and a subtransient reactance of 0.30 pu based on its own rating. A three phase balanced fault occurs at the terminals of one motor as shown in the figure below. Find the subtransient fault current and subtransient current in breaker. M1) 132/6.6 KV СВ 38 CB Infinite Bus M2 Fault
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 13.2 (line-to-line) kV. The step-down transformer has a turn ratio of 15:1 and it has a Y-connected, balanced load of 0.667 +j 0.111 ohms connected to its secondary side. A capacitor bank of -j0.239 ohms is added parallel to the load. Assuming an ideal transmission line, the load voltage (line-to-neutral) would be: A. 5118 V B. 6.2 kV C. 8865 V D. None of the other choices are correct E. 4225 V
Q3/ For the system shown in figure. The generator is supplying 1.0 pu MW power under prefault condition. When three-phase fault occur at point F. What should the value of fault reactance must be to make the critical clearing angle equal to 58.9. Sc j0.1 j0.1 10.21 BE j0.38 38 j0.21 IEgl-12 pu 10.19 F 10.19 IVI-1.00 pu j0.1 j0.1 Q4/ Figure below shows the one-line diagram
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.
L-type equivalent circuit and parameters for a continuous sinusoidal phase of a 5.5 kW, 1460 rpm, line voltage 220 V and frequency 50 Hz star-connected 3-phase ASM, ignoring core (iron) losses given as follows: R1=0.21 Ohm, R2=0.18 Ohm, X1=X2=0.66 Ohm and Xm=9.9 Ohm How many times the inrush current will be the rated current when the ASM is started directly? Answer options group 3.7473 5.2280 8.0815 7.1534 1.2558 4.3763 2.6455 6.3414
pls solve in less than 30 min.