21EE34 Transformers and Generators syllabus for EE

Single phase Transformers:

Operation of practical transformer under no-load and on-load with phasor diagrams. Open circuit and Short circuit tests, calculation of equivalent circuit parameters and predetermination of efficiency-commercial and all-day efficiency. Voltage regulation and its significance.

Three-phase Transformers:

Introduction, Constructional features of three-phase transformers. Choice between single unit three-phase transformer and a bank of three single-phase transformers. Transformer connection for three phase operation– star/star, delta/delta, star/delta, zigzag/star and V/V, comparative features. Phase conversion-Scott connection for three-phase to two-phase conversion. Labeling of three-phase transformer terminals, vector groups.

Tests, Parallel Operation of Transformer & Auto Transformer:

Polarity test, Sumpner’s test, separation of hysteresis and eddy current losses

Parallel Operation of Transformers:

Necessity of Parallel operation, conditions for parallel operation– Single phase and three phase. Load sharing in case of similar and dissimilar transformers.

Auto transformers and Tap changing transformers:

Introduction to autotransformer-copper economy, equivalent circuit, no load and on load tap changing transformers.

Three-Winding Transformers & Cooling of Transformers:

Three-winding transformers. Cooling of transformers.

Direct current Generator:

Armature reaction, Commutation and associated problems,

Synchronous Generators:

Armature windings, winding factors, e.m.f equation. Harmonics–causes, reduction and elimination. Armature reaction, Synchronous reactance, Equivalent circuit.

Synchronous Generators Analysis:

Alternator on load. Excitation control for constant terminal voltage. Voltage regulation. Open circuit and short circuit characteristics, Assessment of reactance-short circuit ratio, synchronous reactance, Voltage regulation by EMF, MMF and ZPF methods.

Synchronous Generators (Salient Pole):

Effects of saliency, two-reaction theory, Parallel operation of generators and load sharing. Methods of Synchronization, Synchronizing power, Determination of Xd & Xq – slip test

Performance of Synchronous Generators:

Power angle characteristic (salient and non salient pole), power angle diagram, reluctance power, Capability curve for large turbo generators. Hunting and damper windings.

Course outcome (Course Skill Set)

At the end of the course the student will be able to :

• Understand the construction and operation of 1-phase, 3-Phase transformers, and Autotransformer.
• Analyze the performance of transformers by polarity test, Sumpner’s Test, phase conversion, 3-phase connection, and parallel operation.
• Understand the construction and working of AC and DC Generators.
• Analyze the performance of the AC Generators on infinite bus and parallel operation.
• Determine the regulation of AC Generator by Slip test, EMF, MMF, and ZPF Methods.

Assessment Details (both CIE and SEE)

• The weightage of Continuous Internal Evaluation (CIE) is 50% and for Semester End Exam (SEE) is 50%.
• The minimum passing mark for the CIE is 40% of the maximum marks (20 marks out of 50).
• A student shall be deemed to have satisfied the academic requirements and earned the credits allotted to each subject/ course if the student secures not less than 35% ( 18 Marks out of 50)in the semester-end examination(SEE), and a minimum of 40% (40 marks out of 100) in the sum total of the CIE (Continuous Internal Evaluation) and SEE (Semester End Examination) taken together

Continuous Internal Evaluation:

Three Unit Tests each of 20 Marks (duration 01 hour)

• First test at the end of 5th week of the semester
• Second test at the end of the 10th week of the semester
• Third test at the end of the 15th week of the semester

Two assignments each of 10 Marks

• First assignment at the end of 4th week of the semester
• Second assignment at the end of 9th week of the semester Group discussion/Seminar/quiz any one of three suitably planned to attain the COs and POs for 20 Marks (duration 01 hours)
• At the end of the 13th week of the semester The sum of three tests, two assignments, and quiz/seminar/group discussion will be out of 100 marks and will be scaled down to 50 marks (to have less stressed CIE, the portion of the syllabus should not be common /repeated for any of the methods of the CIE. Each method of CIE should have a different syllabus portion of the course).

CIE methods /question paper is designed to attain the different levels of Bloom’s taxonomy as per the outcome defined for the course.

Semester End Examination:

Theory SEE will be conducted by University as per the scheduled timetable, with common question papers for the subject (duration 03 hours)

• The question paper will have ten questions. Each question is set for 20 marks.
• There will be 2 questions from each module. Each of the two questions under a module (with a maximum of 3 sub-questions), should have a mix of topics under that module.

The students have to answer 5 full questions, selecting one full question from each module.

Suggested Learning Resources:

Textbooks

(1) Electric Machines, D. P. Kothari, et al, 4 th Edition, 2011.

(2) Principals of Electrical Machines, V.K Mehta, Rohit Mehta, S Chand, 2nd edition, 2009

Reference Books

(1)Electric Machines, MulukuntlaS.Sarma,at el, Cengage, 1st Edition, 2009.

(2)Electrical Machines, Drives and Power systems, Theodore Wildi, Pearson, 6th Edition, 2014.

(3)Electric Machines, Ashfaq Hussain, Dhanpat Rai & Co, 2nd Edition, 2013.