Transformers / by BHEL (Bharat Heavy Electricals Limited).

Format:

Book

Author/Creator:

Bharat Heavy Electricals Limited, author.

Language:

English

Subjects (All):

Electric transformers.

Electric motor industry.

Electric reactors, Shunt.

Physical Description:

1 online resource (xviii, 614 pages) : illustrations, figs., tables.

Edition:

2nd ed.

Place of Publication:

New York, N.Y. : McGraw-Hill Education LLC., c2003.

Contents:

Foreword

F. Preface to the second edition

G. Preface to the first edition

H. Acknowledgements

I. Editorial committee

1. Introduction

2. Principles of transformers

Working principle of a transformer

Elementary theory of an ideal transformer

Emf equation of a transformer

Voltage transformation ratio (k)

Ideal transformer

Transformer having winding resistance but no magnetic leakage

Magnetic leakage

Transformer with resistance and leakage reactance

Equivalent circuit

Regulation

Losses in transformers

Efficiency

The auto-transformer

Three-winding transformer

Parallel operations of transformers

Appendix

References

3. Materials used in transformers

Insulating oil

Insulating paper

Pressboard

Wood

Insulated copper conductor for windings

Crepe paper covered flexible copper cable

Sealing materials

Cold rolled grain-oriented electrical steel sheet (crgo)

Structural steel

Future trends

4. Magnetic circuit

Material

Design of magnetic circuit

Optimum design of core

Manufacturing

5. Windings and insulation

Types of windings

Surge voltage behaviour of windings

Internal heat transfer in windings

Insulation design

Electric field plotting

Finite difference method (fdm)

6. Voltage regulation and tapchanger

Off-circuit tapchanger

On-load tapchanger (oltc)

Constructional and operational features of oltc

Manual and electrical operation of tapchanger

Automatic control of tapchanger

Tapchanger selection

Latest trends in tapchanger design

Reference

7. Electromagnetic forces in power transformers

Leakage flux in a typical two winding transformer

Nature of forces

Basic formula and methods for force evaluation

Radial forces

Axial forces

Roth's method of force calculation

Modes of failure of windings and design of windings

Strengthening of coils to withstand short-circuit forces

Design of clamping structures

List of symbols

8. Cooling arrangements

Various types of cooling

Cooling arrangements

Propeller type fans

Transformer oil pump

Flow indicators

Stress and hydraulic analysis of pipework

9. Design procedure

Specifications of a transformer

Selection of core diameter

Selection of flux density

Selection of type of core

Selection of leg length

Selection of type of windings

Selection of tapchanger

Calculation of number of turns

Selection of conductor and current density

Calculation of lateral and axial dimensions of coils

Ampere-turn balancing

Reactance calculation

Iron weight and losses

Copper weight and losses

Stray losses in transformer

Stray loss control

Impulse calculation

Mechanical forces in windings

Temperature gradient and cooling calculation

Typical design calculations for two winding and auto-transformers

References.

10. Structural design of transformer tank

Types of tank constructions

Structural design of transformer tanks

Testing of tanks

11. Transformer auxiliaries and oil preservation systems

Gas operated (buchholz) relay

Temperature indicators

Pressure relief valve

Oil level indicator

Bushing and cable sealing box

Silicagel breather

Gas sealed conservators

Thermosyphon filters

Bellows and diaphragm sealed conservators

Refrigeration breathers

12. Manufacturing and assembly

Core building

Preparation of windings

Winding assembly

Core and winding assembly

Terminal gear assembly

Placement of core and winding assembly in tank

Processing

Servicing of transformer

Tanking

13. Drying and impregnation

Basic principles of drying

Conventional vacuum drying

Vapour phase drying

14. Testing of transformers and reactors

Testing of power transformers

Impulse testing

Partial discharge testing

Testing of reactors

Short-circuit testing of power transformers

15. Standards on power transformers

First revision of is: 2026

Other related standards

New standards

Standard specification of a power transformer

Appendix i

I. Indian standards related to power transformers

Ii. Iec publications

16. Loading and life of transformers

Life of a transformer

Ageing of insulation

Law of insulation ageing

Significance of weighted value of ambient temperature

Relationship between weighted ambient, winding rise and hot-spot temperatures

Determination of weighted ambient temperature

Relationship between weighted ambient and load

Alternative approach for the calculation of weighted ambient

Transformer loading guides

Loading by hot-spot temperature measured by wti

Selection and use of a transformer

Annexure i correction factors

Annexure ii

Annexure iii loading table transformers onan/onaf cooled (to is : 2026)

17. Erection and commissioning

Despatch

Inspection upon arrival at site

Handling

Installation

Commissioning

Maintenance

Dos for power transformer

Don'ts for power transformers

Dos and don'ts for hv condenser bushings

18. Transformer protection

Protection against external faults

Protection against internal faults

19. Reactors

Series reactors

Shunt reactor

Neutral earthing reactor

Tuning for filter reactors

Arc suppression reactors

Earthing transformers (neutral couplers)

Standards on reactors

20. Traction transformers

Types of traction transformers

Special considerations

Design and constructional features

Traction transformer for thyristor controlled locomotives

21. Rectifier transformers

Comparison between rectifier transformer and power transformer

Rectifier circuits

Design features of rectifier transformers

Transductors

Constructional features of rectifier transformers Tank design

Testing

22. Convertor transformers for hvdc systems

Higher harmonic currents

Dc magnetization

Dc bushings

On load tapchanger

Influence of impedance variation

Connections

Specifications

Manufacturing features

Tests

23. Controlled shunt reactor

Controlled shunt reactor (csr) principle

Controlled shunt reactor transformer (csrt)

Special features of the controlled shunt reactor transformer

Controlled shunt reactor much more than a shunt reactor

Conclusion

24. Designing and manufacturing?a short-circuit proof transformer

Forces during short-circuit

Various considerations to design a transformer suitable for short-circuit duty

Manufacturing aspects

Quality aspects

25. High voltage condenser bushings

Introduction

Classification of bushings

Design of bushing

Constructional details and main parts of bushing

Testing of bushing

Factors affecting the performance of bushing

Condition monitoring at site

Dos and do nots for hv condenser bushings

26. Computerisation?a tool to enhance engineering productivity

27. Condition monitoring, residual life assessment and refurbishment of transformers

Analysis method

Physical inspection

Residual life assessment (rla)

Different techniques for life estimation

Methodology adopted

Conventional and special tests on oil samples

Refurbishment

Annexure i format for data collection history of transformer

28. Transformers: an overview

A. Solved examples.

Notes:

Includes bibliographical references and indexes.

Description based on cover image and table of contents, viewed on Sep. 18, 2014.

ISBN:

9780070483156

0070483159

Access Restriction:

Restricted for use by site license.