Course: Certificate in Three Phase Power and Plant Distribution Guided Learning Hours: 24 Pre-requisite: Basic knowledge in Electricity or Electronics

Abstract This course presents an introduction to how Three Phase Power is defined and applied to transformers and other loads. The learner will understand the construction of voltage transformers and how they step up and step down voltages. Common delta and star connections will also be discussed and the operating principles of Buck-Boost transformers and Autotransformers will be introduced. Learning will take place through a combination of lectures and laboratory sessions

Target Audience Electricians, engineers, technicians, technical and maintenance personnel

Learning Outcomes

On completion of this course, learners will be able to:

1. Identify the various types of electrical loads

2. Understand single phase and three phase power

3. Understand how transformers work

4. Demonstrate how to make various transformer connections

Course Content

1. Identify the various types of electrical loads

Resistive: Definition of resistive load, resistance, sinusoidal voltage and current; power factor; resistance to current flow in typical conductor (wire) used in electrical distribution; measurement of resistance; common symbols; relationship between resistance and current flow; phase relationship between current flow and applied voltage in resistive circuits.

Inductive: Definition of inductive load and inductance; coils and magnetic fields; effect of inductance on current flow in electric circuits; real and reactive power; impedance; unit of measurement; common symbols; relationship between inductance and current flow; inductive reactance; phase relationship between current flow and applied voltage in inductive circuit.

Capacitive: Definition of capacitive load and capacitance; applying a voltage to a capacitor; reactive power associated with capacitance; unit of measurement; capacitive reactance; common symbols; phase relationship between current flow and applied voltage in capacitive circuit.

2. Understand single phase and three phase power

Generation: Diesel generators and turbines; low, medium, high voltage; transmission and distribution voltage; transmission line and switchgear; rotating magnetic field; paralleling of generators. Distribution: Common utilization voltages; residential, commercial and industrial electrical distribution systems; circuit breakers, load centre, panel boards and switchboards; single phase verses three phase distribution; electrical power measurement; symbols and conventions; line, neutral, ground; electrical conductors (wires and cables); cable color code.

3. Understand how transformers work

Transformers: Magnetic field and magnetic coupling; induction; transformer windings and core construction; core and winding material; voltage transformation; step-up and step-down; oil filled, dry type, cast coil transformers; ideal and practical transformer; transformer taps; definition of impedance; BIL and kVA ratings; paralleling of transformers for increased capacity.

4. Demonstrate how to make various transformer connections

Star and Delta connections and how they are used; advantages and disadvantages of Star and Delta connections; open delta connection; 1-1 isolation transformer connection; autotransformer connection; Buck-Boost transformer connections – 1 phase and 3 phase.

Assessment Criteria

In order to achieve Learning Outcome…

The Learner must…

1. Identify the various types of electrical

loads

1.1 Understand the basic electrical parameters: resistance, inductance, capacitance

1.2 Be able to apply Ohms Law to AC circuit 1.3 Understand resistive and reactive loads 1.4 Be able to describe impedance and

power factor 1.5 Differentiate between Distribution and

Motor loads

2. Understand single phase and three phase

power

2.1 Explain what is meant by ‘3 phase power’ and be able to differentiate it from 1 phase power

2.2 Describe how generators work 2.3 List the parameters that define how

transformers are selected 2.4 Describe how to apply 3 phase power to

loads for efficiency 2.5 Identify the naming conventions used

for 3 phase systems 2.6 Solve basic mathematical problems

involving 3 phase supply 2.7 Be able to measure 3 phase power 2.8 Explain what is meant by balanced and

unbalanced 3 phase supply and the difference between 3 wire and 4 wire systems

3. Understand how transformers work

3.1 Describe the principle of magnetic coupling and how it is used in transformer construction to convert from one voltage to another.

3.2 List the basic materials used in the manufacture of transformers

3.3 Explain how transformers are wound and how windings define Step-up, Step-down, variable and isolating features

3.4 Specify what is an ideal transformer and understand how to use the ideal transformer equation

3.5 Be able to differentiate between

different types of transformers 3.6 Describe the parameters used to specify

a transformer

4. Demonstrate how to make various

transformer connections

4.1 Be able to connect transformers in Star (Wye) or Delta

4.2 Understand the configuration of the windings and the phase angle difference between them (Vector Group)

4.3 Determine when to use Y-Δ, Δ-Y, Δ-Δ and Y-Y connections

4.4 Define MVA, Impedance, IC, BIL, Taps and other basic parameters that specify a transformer

4.5 Explain non-isolating transformers and identify their uses

4.6 Demonstrate how to connect ‘isolating transformer’ windings in a non-isolating configuration

4.7 Explain how autotransformers and buck-boost transformers work and when to apply them

4.8 Be able to size buck-boost transformers (1 phase and 3 phase configuration)

4.9 Describe the various services offered by TTEC (voltage, kVA . . .)

4.10 Describe a typical power system from generation to distribution

Essential Learning Resources: Learners will need access to a wide range of publications relating to three phase power and a suitably equipped laboratory for practical training.

Textbooks and Manuals

1. Understanding 3 Phase Power and Plant Distribution - Industrial Text and Video Co. Publication