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NZQA registered unit standard
12390 version 5
Page 1 of 8
Title
Demonstrate knowledge of electricity supply systems
Level
3
Credits
5
Purpose
People credited with this unit standard are able to demonstrate
knowledge of: the principles of electricity; measurement of
electrical quantities; electricity generation; transmission,
distribution and reticulation; and switching stations, substations
and associated equipment.
Classification
Electricity Supply > Electricity Supply - Core Skills
Available grade
Achieved
Explanatory notes
1
This unit standard is intended for, but not restricted to, off-job assessment.
2
Performance and work practices in relation to the outcomes and evidence
requirements must comply with all current legislation, especially the Electricity Act
1992, and any regulations and codes of practice recognised under that statute; the
Health and Safety in Employment Act 1992; and the Resource Management Act
1991. Electricity supply industry codes of practice and documented industry
procedures include the current version of the Safety Manual – Electricity Industry
(SM-EI) (Wellington: Electricity Engineers’ Association). A full list of current
legislation and industry codes is available from the Electricity Supply Industry
Training Organisation, PO Box 1245, Hamilton 3240.
3
This unit standard includes the ability to recognise where particular items of electricity
supply plant and equipment can be expected to be in the overall supply system.
4
This unit standard excludes the detailed knowledge of electricity supply plant and
equipment items.
5
The following terms and abbreviations relate to this unit standard:
SCADA –Supervisory Control and Data Acquisition system used for control,
indication, and monitoring purposes.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
12390 version 5
Page 2 of 8
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of the principles of electricity.
Evidence requirements
1.1
The physical nature of current is explained.
Range
1.2
The requirements for a flow of current are defined.
Range
1.3
capacitive reactance, inductive reactance, capacitors, inductors,
resistance and reactance combinations.
The concepts of leading and lagging currents are explained.
Range
1.9
cycles per unit of time.
The concepts of capacitance, inductance, reactance and impedance are
explained.
Range
1.8
wave forms – unidirectional, pulsating, periodic, sinusoidal.
The concept of frequency is explained.
Range
1.7
electromotive force source (for example battery), continuous
circuit, resistive load.
DC and AC electromotive forces and current are defined.
Range
1.6
conductor, semi-conductor and insulator chemistry.
Electromotive force, circuit and load are defined and relationship among
electromotive force, current and resistance is explained.
Range
1.5
potential difference, conductor.
Conductors, semi-conductors, and insulators are defined.
Range
1.4
flow of electrons, conductor.
leading and lagging current wave forms with respect to
electromotive force waveform.
The concepts of work, energy, heat, electrical energy, their equivalence and
transformation are explained.
Range
force x distance, potential energy, kinetic energy, mass x
temperature rise x specific heat, current x electromotive force,
current x resistance2, Joule’s equivalent.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
1.10
Mechanical, heating and electric power are explained.
Range
1.11
rate of doing work, rate of heating, rate of generating or
consuming electrical energy.
The concepts of reactive and apparent power and energy are explained.
Range
1.12
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vectors 90 degrees out of phase, vector addition.
The concept of power factor is explained.
Range
ratio of real energy to apparent power, cosine of leading or lagging
current angle.
Outcome 2
Demonstrate knowledge of the measurement of electrical quantities.
Evidence requirements
2.1
Multipliers up to one million and down to one millionth in the international
system of units are defined.
Range
2.2
Units for measurement of potential difference, electromotive force, current,
resistance, capacitance, inductance, capacitive reactance, inductive reactance,
and impedance are defined.
Range
2.3
kilo, mega, milli, micro.
volt, ampere, ohm, farad, henry.
Units for measurement of energy, power, electrical energy (electricity) and
electric power (active and reactive) are defined.
Range
joule = watt-second, calorie, kilowatt-hour, watt, kilowatt, reactive
volt-ampere, volt-ampere.
Outcome 3
Demonstrate knowledge of the principles of electricity generation.
Range
conservation of energy, magnetic field and current relationships.
Evidence requirements
3.1
The effect of current carrying conductor is explained.
Range
3.2
magnetic field present around conductor.
The effect of passing current through conductor in magnetic field is explained.
Range
force moves conductor across field flux lines.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
3.3
The effect on conductor forced through magnetic field is explained.
Range
3.4
constant system frequency and voltage.
The effects of varying the magnetic field and generated power with generator
connected to infinite busbar are explained.
Range
3.11
rotational speed constant, increases or decreases.
The concept of an infinite busbar is explained.
Range
3.10
field flux increased, induced voltage increased.
The effects of balance and imbalance between generator power output and load
power consumption are explained.
Range
3.9
static field, electromagnetic force induced in rotating winding,
commutator and brushes to provide unidirectional output.
The effect on the generated electromotive force of varying the current in the
electromagnetic field coils in a generator is outlined.
Range
3.8
rotating field, electromagnetic force induced in stator winding.
Commutation and DC generation are explained.
Range
3.7
magnetic field effect of conductor coil.
Simple AC generation by field rotation is explained.
Range
3.6
current induced in conductor.
Electromagnetic field is explained.
Range
3.5
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current leads or lags system voltage, generator accepts greater or
lesser load.
The concepts of single phase and three phase generation are explained.
Range
single set of waveforms, three sets of waveforms, 120º
displacement.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
12390 version 5
Page 5 of 8
Outcome 4
Demonstrate knowledge of the principles of electricity transmission, distribution and
reticulation.
Evidence requirements
4.1
The concept of conductor current carrying capacity is explained.
Range
4.2
The basic construction of a transformer is described.
Range
4.3
safety, segregation of conductors of differing phases, insulation
coordination.
The relationship of line voltage to phase voltage to earth is defined.
Range
4.9
safety, insulation levels, protection.
The requirement for insulation of conductors in electrical systems is explained.
Range
4.8
step-up and step-down secondary electromotive force.
The concept of referencing systems to the general mass of earth is explained.
Range
4.7
magnetising current, primary and secondary ampere/turns.
The purpose of transformers in electricity carriage to point of use is explained.
Range
4.6
primary turns, secondary turns, winding taps, tapchanger.
The concept of ampere/turns balance in transformers is explained.
Range
4.5
core of magnetic material, insulated conductor windings, terminals,
main tank, insulating oil, conservator tank, means of cooling, dry
type transformers, Bucholz relays.
The effects of turns ratio in transformer on output electromotive force for given
input are outlined.
Range
4.4
conductor cross-sectional area, current density, conductor
resistance, heating, heat flow balance.
delta, star phasors, 3 factor.
Common transmission line voltages used in New Zealand are defined.
Range
220 kV, 110 kV, 66 kV, 50 kV.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
4.10
Common sub-transmission, distribution and reticulation line voltages used in
New Zealand are defined.
Range
4.11
66 kV, 50 kV, 33 kV, 22 kV, 11 kV, 400 V.
The basic principles of high voltage direct current transmission are outlined.
Range
4.12
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two wire with earth return, insulation levels, converter stations,
rectifiers, inverters, gains over AC transmission, AC and DC
transmission costs breakeven point.
Common overhead power line and power cable configurations are described.
Range
single phase and three phase conductors, bundle conductors,
insulators, towers, poles, cross-arms, earthing conductors, laid-up
conductors, sheaths, armouring, serving.
Outcome 5
Demonstrate knowledge of switching stations, substations and associated equipment.
Range
switchyards, transmission, sub-transmission and distribution substations,
transformers, switchgear, surge diverters, protective equipment, voltage and
current transformers, load control equipment, communications, line traps,
SCADA equipment.
Evidence requirements
5.1
The concepts of system reliability and security are outlined and overhead line
and cable differences in respect to these are explained.
Range
5.2
The concepts of faults and fault current are explained.
Range
5.3
phase to phase faults, phase to earth faults, typical values.
The detection of fault currents and principles of overcurrent and earth fault
protective relays are described.
Range
5.5
insulator or insulation failure, lightning, trees, line or cable
damage, impedance change, fault current determination.
The concepts of overcurrents and earth fault currents are explained.
Range
5.4
ability to continue non-interrupted supply of electricity, ability to
restore supply after interruption, time for repair.
current transformers, protective relays, definite time, inverse time.
The concept of fault current breaking is outlined.
Range
current zero arc extinction, restrike, fuse-links, fault level ratings.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
5.6
The use of disconnectors and earth switches are explained.
Range
5.7
isolation and earthing of conductors and plant.
Common switching station and circuit layouts are described.
Range
5.8
single and double busbar, duplicate feeders, ring feeders.
Standard sub-transmission and distribution substation configurations are
described.
Range
5.9
high voltage switchgear, transformer(s), low voltage switchgear,
protection equipment, local transformer.
Standard means of remote switching controllable loads within distribution
systems are described.
Range
5.10
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pilot wire, mains ripple frequency injection.
Standard means of remote control of switching stations and substations are
described.
Range
SCADA, telecommunications.
Planned review date
31 December 2015
Status information and last date for assessment for superseded versions
Process
Version Date
Last Date for Assessment
Registration
1
26 August 1997
31 December 2013
Review
2
30 November 2000
31 December 2013
Revision
3
11 February 2004
31 December 2013
Rollover and
Revision
4
26 November 2007
31 December 2013
Review
5
9 December 2010
N/A
Accreditation and Moderation Action Plan (AMAP) reference
0120
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA, or
an inter-institutional body with delegated authority for quality assurance, before they can
report credits from assessment against unit standards or deliver courses of study leading
to that assessment.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017
NZQA registered unit standard
12390 version 5
Page 8 of 8
Industry Training Organisations must be granted consent to assess against standards by
NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and
which are assessing against unit standards must engage with the moderation system that
applies to those standards.
Consent requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Electricity Supply Industry Training Organisation [email protected] if
you wish to suggest changes to the content of this unit standard.
Electricity Supply Industry Training Organisation
SSB Code 101813
 New Zealand Qualifications Authority 2017