NZQA registered unit standard
28886 version 1
Page 1 of 4
Title
Demonstrate knowledge of power transformers used in substations
Level
4
Credits
3
Purpose
People credited with this unit standard are able to demonstrate
knowledge of: the types of power transformers and regulators;
power transformer principles; power transformer components
and construction; power transformer alarms and protection
systems; power transformer maintenance; and condition
assessment of power transformers.
Classification
Electricity Supply > Electricity Supply - Power System
Maintenance
Available grade
Achieved
Explanatory notes
1
This unit standard is intended for assessment off-job. The range statements and
evidence requirements across the unit standard can be applied according to industry
specific equipment, procedures, and processes as applied in the electricity supply
industry.
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 subsequent amendments, any regulations, codes of practice
recognised under that statute; Health and Safety in Employment Act 1992 and any
subsequent amendments;, Resource Management Act 1991 and any subsequent
amendments; electricity supply industry codes of practice; and documented
enterprise procedures. These include the latest version of Safety Manual –
Electricity Industry (SM-EI) Wellington: Electricity Engineers’ Association.
A full list of current legislation and industry codes is available from:
Infrastructure Industry Training Organisation
PO Box 1245
Hamilton 3240.
3
The phrase in accordance with industry requirements is implicit in all outcomes and
evidence requirements in this unit standard.
4
Definitions
Asset owner refers to the owner of an electricity supply network that takes its point of
supply from Transpower NZ, and delivers electricity to industrial, commercial and
residential customers.
Industry requirements include all asset owner requirements; manufacturers’
specifications; and enterprise requirements which cover the documented workplace
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
28886 version 1
Page 2 of 4
policies, procedures, specifications, business, and quality management requirements
relevant to the workplace in which assessment is carried out.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of types of power transformers and regulators in a substation.
Evidence requirements
1.1
Commonly used types of power transformers and regulators are identified.
Range
1.2
Single and 3 phase power transformers, autotransformer,
regulator, local service transformer.
The function of transformers and regulators are described.
Outcome 2
Demonstrate knowledge of power transformer principles.
Evidence requirements
2.1
The theory of the operation of a transformer is explained.
2.2
Characteristics of power transformers are explained.
Range
2.3
connections, phasing, vector groups, losses, transformer
percentage impedances, voltage regulation, tertiary windings,
paralleled transformers
The function and operation of tapchangers is explained.
Range
on-load, off-load
Outcome 3
Demonstrate knowledge of power transformers components and construction.
Evidence requirements
3.1
Components and construction of transformers are identified and explained.
Range
may include but is not limited to: cores, windings, insulation,
cooling systems, tanks, tapchangers, input/output connections,
earthing arrangements.
Outcome 4
Demonstrate knowledge of power transformer protection systems.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
28886 version 1
Page 3 of 4
Evidence requirements
4.1
Reasons for transformer protection are identified and explained.
Range may include but not limited to: input supply, output loading, fault loading,
temperature, gas evolution, oil level changes, voltage impulses
4.2
Protection systems are explained and demonstrated.
Range
may include but is not limited to: electrical, gas and oil,
temperature, impulse, tap changing.
Outcome 5
Demonstrate knowledge of power transformer maintenance.
Evidence requirements
5.1
Inspection and service requirements for power transformers are identified and
explained.
Range
includes but is not limited to: protective coating, seismic, oil leaks,
cooling equipment, tap changers, cabling, wiring, terminations,
protective relays.
Outcome 6
Demonstrate knowledge of condition code assessment of power transformers.
Evidence requirements
6.1
Condition coding process is described for power transformers.
Planned review date
31 December 2020
Status information and last date for assessment for superseded versions
Process
Version Date
Last Date for Assessment
Registration
1
17 March 2016
N/A
Consent and Moderation Requirements (CMR) reference
0120
This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
28886 version 1
Page 4 of 4
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA,
before they can report credits from assessment against unit standards or deliver courses
of study leading to that assessment.
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.
Requirements for consent to assess and an outline of the moderation system that applies
to this standard are outlined in the Consent and Moderation Requirements (CMR). The
CMR 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 Infrastructure Industry Training Organisation at
qualifications@infrastructureito.org.nz if you wish to suggest changes to the content of this
unit standard.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016