Introductory Circuit Analysis (13th Edition)
13th Edition
ISBN: 9780133923605
Author: Robert L. Boylestad
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Related questions
Question
Transcribed Image Text:PROBLEMS
3.1. A three-phase, 318.75-kVA, 2300-V alternator has an armature resistance of
0.35 N/phase and a synchronous reactance of 1.2 n/phase. Determine the
no-load line-to-line generated voltage and the voltage regulation at
(a) Full-load kVA, 0.8 power factor lagging, and rated voltage.
(b) Full-load kVA, 0.6 power factor leading, and rated voltage.
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution
Trending nowThis is a popular solution!
Step by stepSolved in 3 steps with 3 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Please answer all subparts for like either dislike is ready at least 5 subparts... A 3-phase, 450 V, 2-pole, 50 Hz, wye-connected, synchronous alternator. Xs = 1.62 ohm/phase. Connected to an infinite bus and supplies 120 kW with a power angle of 35 degrees.Neglect losses and find:a. turbine torque supplied to alternator.b. excitation voltage.c. active, reactive power and machine power factor.d. neglecting saturation effects of the field, the excitation voltagee. if the field current is reduced to 80% of its original value in part a.f. the turbine speed for 60 Hz operation.arrow_forwardEo(LL) (V) a) 3000 b) 2500 2000 1500 1000 500 0 No-load excitation curve @3600rpm 0 1 2 3 4 5 6 DC Excitation current (A) 7 The figure above shows the no-load excitation (LL) curve of a 3-ph, 2-pole, 60 Hz, 1000 kVA, 2.3 kV synchronous alternator at rated speed. The alternator has negligible resistance and Synchronous Reactance Xs = 1.2 n/phase. If the alternator is synchronized to the Power Grid at 2.3 kV (Line to Line), calculate the following: 8 9 10 The value of excitation current required for full load current at 0.7 pf lagging (over-excited). |EO(LL)I IF The alternator current and reactive power when it is delivering 80% rated power (0.8 MW) and its DC excitation current is 4 A. IL Q3pharrow_forwardA 3Ø, Y-connected alternator is rated at 1,600KVA, 13.5KVv. The armature effective AC resistance per phase is 1.50. 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 and explain briefly your answer on one(1) sentence.arrow_forward
- Evaluate the Merz-Price circulating-current scheme for an Alternator protection with appropriate diagram.arrow_forwardBy 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?arrow_forwardShow 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]arrow_forward
- 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.arrow_forwardwhich Q5: Estimate the synchronous impedance for an 11 kV, three-phase, 50 Hz, 20 MVA alternator develops rated emf on no-load with a field current of 20 A. A field current of 12 A produces a short circuit current equal to rated current.arrow_forwardExplain the concept of power quality and the various disturbances that can affect it, such as harmonics and transients.arrow_forward
- Draw a complete circuit diagram of 1 phase synchronous alternator including the field excitation circuit. Then, draw the phasor diagram of the generator a general leading power factor. Include the phase resistance in the diagram.arrow_forwardA 30 MVA, three-phase, wye-connected, 60 Hz, 13.8 kV synchronous alternator has negligible stator resistance and synchronous reactance of 10 W/phase. Calculate the % voltage regulation of the alternator when it is operation in isolation (stand-alone) and delivering rated MVA to a 0.866 pf leading load at 13.8 kV. Calculate the % voltage regulation of the alternator when it is operation in isolation (stand-alone) and delivering rated MVA to a 0.707 pf lagging load at 13.8 kV.arrow_forwardA three-phase star-connected alternator is rated at 1500 KVA, 11 KV, The armature resistance and synchronous reactance are 1.5 Q and 25 Q per phase respectively. Calculate the percentage regulation for a load of a) 45% load at 0.7 power factor lagging. b) 65% load at 0.65 power factor leading. a) b)arrow_forward
arrow_back_ios
arrow_forward_ios
Recommended textbooks for you
- Introductory Circuit Analysis (13th Edition)Electrical EngineeringISBN:9780133923605Author:Robert L. BoylestadPublisher:PEARSON
Delmar's Standard Textbook Of ElectricityElectrical EngineeringISBN:9781337900348Author:Stephen L. HermanPublisher:Cengage Learning
Programmable Logic ControllersElectrical EngineeringISBN:9780073373843Author:Frank D. PetruzellaPublisher:McGraw-Hill Education 
Fundamentals of Electric CircuitsElectrical EngineeringISBN:9780078028229Author:Charles K Alexander, Matthew SadikuPublisher:McGraw-Hill Education
Electric Circuits. (11th Edition)Electrical EngineeringISBN:9780134746968Author:James W. Nilsson, Susan RiedelPublisher:PEARSON
Engineering ElectromagneticsElectrical EngineeringISBN:9780078028151Author:Hayt, William H. (william Hart), Jr, BUCK, John A.Publisher:Mcgraw-hill Education,
Introductory Circuit Analysis (13th Edition)
Electrical Engineering
ISBN:9780133923605
Author:Robert L. Boylestad
Publisher:PEARSON
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:9781337900348
Author:Stephen L. Herman
Publisher:Cengage Learning
Programmable Logic Controllers
Electrical Engineering
ISBN:9780073373843
Author:Frank D. Petruzella
Publisher:McGraw-Hill Education
Fundamentals of Electric Circuits
Electrical Engineering
ISBN:9780078028229
Author:Charles K Alexander, Matthew Sadiku
Publisher:McGraw-Hill Education
Electric Circuits. (11th Edition)
Electrical Engineering
ISBN:9780134746968
Author:James W. Nilsson, Susan Riedel
Publisher:PEARSON
Engineering Electromagnetics
Electrical Engineering
ISBN:9780078028151
Author:Hayt, William H. (william Hart), Jr, BUCK, John A.
Publisher:Mcgraw-hill Education,