4. A 300 MVA, 20 kV three-phase generator has a sub transient reactance of 20%. The generator supplies a synchronous motors and static load over 64-km transmission line having transformers at both ends, as shown in Fig. 1.11. The motors, all rated 13.2 kV, are represented by just two equivalent motors. Rated inputs to the motors are 200 MVA and 100 MVA for M1 and M2, respectively. For both motors X" = 20%. The 3-phase load of 60 kVA, 0.6 p.f. load at 10.5 kV is connected at bus. The three phase transformer T1 is rated 350 MVA, 230/20 kV with leakage reactance of 10%. Transformer T2 is composed of three single-phase transformers each rated 127/13.2 kV, 100 MVA with leakage reactance of 10%. Series reactance of the transmission line is 0.5 Q/km. Draw the reactance %3D diagram, with all reactances marked in per-unit. Select the generator rating M. Lead

4. A 300 MVA, 20 kV three-phase generator has a sub transient reactance of 20%. The generator supplies a synchronous motors and static load over 64-km transmission line having transformers at both ends, as shown in Fig. 1.11. The motors, all rated 13.2 kV, are represented by just two equivalent motors. Rated inputs to the motors are 200 MVA and 100 MVA for M1 and M2, respectively. For both motors X" = 20%. The 3-phase load of 60 kVA, 0.6 p.f. load at 10.5 kV is connected at bus. The three phase transformer T1 is rated 350 MVA, 230/20 kV with leakage reactance of 10%. Transformer T2 is composed of three single-phase transformers each rated 127/13.2 kV, 100 MVA with leakage reactance of 10%. Series reactance of the transmission line is 0.5 Q/km. Draw the reactance %3D diagram, with all reactances marked in per-unit. Select the generator rating M. Lead

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...

See similar textbooks

Similar questions

A 600 KVA generator with X"a = 0.22 per unit is connected to a bus through a circuit breaker, as shown in the following figure. Connected through circuit breakers to the same bus are three synchronous motors rated 200 KVA, 2.5 KV, 1.0 power factor, with X"a = 0.15 per unit. The motors are operating at full load, unity power factor and rated voltage, with the load equally divided among the machines. (a) Find the rated symmetrical short-circuit current in Amperes, which must be interrupting breakers A and B for a fault at point P. Simplify the calculations by neglecting the Prefault current. M. GHA B
An 11 kV, three-phase, star-connected alternator has a synchronous impedance of10∟80° Ω/phase and operates at unity power factor on infinite bus bars. It supplies acurrent of 300 A by using a general load diagram. Determine: the full-load current for normal excitation ( motor mode), the current and power factor for 100% excitation on 25% overload (generatormode), the maximum power that the machine can develop in the generator mode for50% excitation
By comparing the principle of operation of a "three" phase generation system with a single-phase system, state what are the bendfits of three phase systems? In your own words, define the "skin effect" in transmission lines and discuss how can it be minimised? Name three advantages of AC transmission in comparison to DC transmission. What are the units of active, reactive and apparent power? The current in a single-phase motor lags 50° behind the voltage. What is the power factor of the motor?
Show that an alternator running in parallel on constant-voltage and frequency bus-bars has a natural time period of oscillation. Deduce a formula for the time of one complete oscillation and calculate its value for a 5000-kVA, 3-phase, 10,000-V machine running at 1500 r.p.m. on constant 50-Hz bus-bars. The moment of inertia of the whole moving system is 14,112 kg-m2 and the steady short-circuit is five times the normal full-load value. ANSWER IS [1.33 second]
A 3Ø, Y-connected alternator is rated at 1,600KVA, 13.5KV. The armature effective AC resistance per phase is 1.5Ω. The percentage regulation for a load of 1,280kW at unity power factor is 3.5%. Determine:(a) synchronous reactance of the alternator(b) %VR at full-load 0.8pf leading(c) What is the effect on %VR value if taken at half-load lagging pf? Justify andexplain briefly your answer on one(1) sentence.
A 50 Hz synchronous generator is supplying 60% of its maximum power to an infinite bus through a reactive network. Due to a certain fault, the reactance of the network between the generator internal voltage and the infinite bus is increased four times. After the fault is cleared, 80% of maximum power can be transferred. Attya Attya Attya (a) Sketch the mechanical power versus power angle curves, in the same figure, undery the different operation conditions, and annotate all the key points on the curves. Ayman Attya Ayman Attya (b) Calculate the power angle before which the fault should be cleared to avoid generator instability. NIE2294 ex NIE2294 ex 2020
Two balanced three-phase motors in parallel, an induction motor drawing 400 kW at 0.8 pf lagging and a synchronous motor drawing 150 KVA at 0.9 pf leading, are supplied by a balanced, three-phase, 4.16-kV source. Line impedances between the source and the load are neglected. a) Determine the power factor of the combined motor-load. b) Determine the magnitude of the line current in each motor. c) Determine the magnitude of the line current delivered by the source.
A 3 phase induction motor operating at rated power can be represented by a balanced delta connected load (ZRY etc) of (3G7 + j10) 2 and is connected to a 3 phase, 4G65 V and 50 Hz supply. (a) Calculate: (i) The three load phase currents (IRY, IYB and IBR). (ii) The three line currents (IR, Iy and IB). The real power (W) in each phase of the load - using 2 different methods to calculate this. (iii) (iv) The real power (W) supplied by each of the supply phases. (v) The total real power (W) from the supply if the induction motor is star connected.