EP-3: Electrical procurement – transformers course

Course Description:

This course is intended to prepare the target persons with the ability to understand and recognize different types, components and accessories of transformers. 

The target Persons:

Design engineers, new graduate engineers, under graduate engineering students, site field engineers, maintenance engineers and electrical technicians.

Skills Development:

On completion of this course the target person will be able to:

• understand transformer terms and definitions
• recognize different types, components and accessories of  transformers
• specify correctly any type of transformer for procurement phase

Course outline

1-Introduction

2-Transformer design:

·        Core

·        Windings

·        Tank

·        Insulation materials

·       Liquid field transformers Cooling materials

3-Transformer types:

A-According to transformed voltage level:

·        Step up transformer

·        Step down transformers

B-According to construction:

·        Core type

·        Shell type

C-According to application

·        Power transformers
                               -  Generatorstep-up transformers

             -  Step-down transformers

             -  System intertie transformers:
                               - Phase Shifting Transformers
                               - HDVC Transformers

             -  Industrialtransformers:
                               - Furnace Transformers (Part One) (Part Two)
                               - Convertor Transformers

             -  Traction transformers

·        Distribution transformers

·        Instruments transformers

·        Rectifier transformers

·        Earthing transformers

·        Pole mounted transformer

·        Furnace transformer

·        Regulating transformer (Auto transformer)

·        Isolation Transformers

D-According to insulation and cooling materials

Oil immersed transformers

Askral transformers

Silicon fluid transformers

Dry type transformers:

Normal type

Cast Risen type

Gas filled type

E-According to number of phases

·        Single phase

·        Three phase

F-According to windings connection methods

·        Star-Star

·        Delta-Delta

·        Star-Delta

·        Delta-Star

·        3-Windings Star-Delta-Star

·        Scott Transformers

·        Zig-Zag Transformers

·        Tap-Changing Transformers

4-K-factor transformer

5-Transformer components:

A.     Terminals

B.     Bushings:

·        Low voltage

·        Condenser

·        High current

C.     Cable connection box

D.     SF6 connection

E.      Coolers:

·        Radiator

·        Corrugated tank

·        Fans

·        Heat exchangers

·        Oil-water coils

·        Oil pumps

F.      Voltage regulating equipments:

·        Off circuit tap changer

·        On load tap changer

6-Transformer accessories:

a.       Thermometer

b.      Built-in current transformer

c.       Dehydrating breathers

d.      Oil preservation tank (conservator tank)

e.       Oil level indicator

f.        Pressure relief devices

g.       Sudden Pressure relief devices

h.       Over voltage protection devices:

·        Internal

·        External

i.         Combustible gas detector

j.        Flow indicator

k.      Transport wheels/skids

l.         Drain valve

  7-Transformer paralleling:

·        Single phase paralleling

·        Three phase paralleling

    8-Transformer protection:

·        Protective devices installed on tank

·        Bockholtz relay

    9-Transformer ratings:

·        Single phase transformers

·        Single phase transformers

   10-Transformer nameplate data

11-Transformer testing:

a)      Routine tests:

·        Winding resistance

·        Voltage ratio and check of phase displacement

·        S.C impedance and load losses

·        No-load losses and current

·        Dielectric routine tests

·        Tests on load tap changers

b)      Type tests:

Temperature rise test

Dielectric type test

12-Transformer troubleshooting

13-Transformer dictionary