14332 version 2
28-Jun-16
1 of 8
ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
level:
4
credit:
8
planned review date:
December 2006
sub-field:
Electricity Supply
purpose:
People credited with this unit standard are able to: prepare
for routine service on oil filled distribution power transformers
11kV to 400V; carry out routine inspections and prescribed
diagnostic tests; carry out servicing; record routine inspection
and servicing; and return equipment to service.
entry information:
Prerequisites: Unit 14287, Use and maintain test instruments
used in high voltage electrical industry; Unit 14294, Carry out
insulating oil sampling and voltage breakdown tests; Unit
14701, Manage electricity supply work control system; Unit
14700, Apply and remove safety measures in an electricity
supply environment; Unit 12296, Apply earths to and remove
earths from electrical conductors, plant and equipment; or
demonstrate equivalent knowledge and skills.
Core electrical theory is essential knowledge underpinning
the performances required by this unit standard.
accreditation option:
Evaluation of documentation and visit by NZQA and industry.
moderation option:
A centrally established and directed external moderation
system has been set up by the Electricity Supply Industry
Training Organisation.
 New Zealand Qualifications Authority 2016
14332 version 2
28-Jun-16
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
special notes:
1
This unit standard can be assessed in a workplace
environment, or in a training or educational environment
if simulated equipment response and examples are
able to be provided, or in a combination of both
environments.
2
Performance and work practices in relation to the
elements and performance criteria must comply with all
current legislation, especially the Electricity Act 1992,
and any regulations, codes of practice recognised
under that statute, Health and Safety in Employment
Act 1992, Building Act 1991, Resource Management
Act 1991, and their subsequent amendments; Electricity
Regulations 1997, Safety Rules Electricity Industry:
Safety Rules for the New Zealand Electricity
Generation, Transmission and Distribution Industry.
(2000) Wellington: Electricity Engineers’ Association of
NZ (SR-EI), and General Safety Guide Electricity
Industry: Guidance on General Safety in the New
Zealand Electricity Generation, Transmission and
Distribution Industry. (2000) Wellington: Electricity
Engineers’ Association of NZ (GSH-EI); Electricity
Engineers’ Association Codes of Practice; Occupational
Safety and Health Approved Codes of Practice; New
Zealand Electrical Codes of Practice (NZECP). A full
list of current legislation and industry codes is available
from:
Electricity Supply Industry Training Organisation
PO Box 1245
HAMILTON.
 New Zealand Qualifications Authority 2016
14332 version 2
28-Jun-16
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
3
Reference to terms, procedures, and specifications in
this unit standard may be taken as including
documented procedures and specifications relevant to
the workplace in which assessment is carried out.
4
All work practices shall meet documented enterprise
maintenance standards, including the quality
management requirements, and the documentation of
activities, events, and decisions.
5
The range of this unit standard is limited to carrying out
preventative maintenance and replacement and/or
repairs of distribution power transformers, 11kV to
400V, normally applied at electricity distribution
substations.
6
The following terms and abbreviations relate to this unit
standard.
IEC
=
International Electrotechnical Commission.
Elements and Performance Criteria
element 1
Prepare for routine service on oil filled distribution power transformers 11kV to 400V.
performance criteria
1.1
The scope of work and equipment are identified and selected in accordance
with servicing procedures.
Range:
may include but is not limited to associated client or enterprise
‘check and/or inspection lists’ and procedures for - power
transformers, voltage regulators, reactors.
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14332 version 2
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
1.2
The anticipated replacement spares are made available.
Range:
1.3
The equipment is released from operational use.
Range:
1.4
may include but is not limited to a careful check of the isolations to
ensure the access permit, or recognised equivalent, provides a
safe work environment.
All safety measures are in place to eliminate, minimise, or control hazards in the
permit area.
Range:
1.7
may include but is not limited to - known defects, operator reports,
client special service requests, oil analysis, dissolved gas
analysis, thermography tests.
The required access permit, or recognised equivalent, is received, checked, and
signed in accordance with the industry and enterprise requirements.
Range:
1.6
may include but is not limited to the correct and timely completion
of all the prescribed equipment release requests.
The defect history and plant history records are scrutinised for indications of
servicing needs.
Range:
1.5
may include but is not limited to the completion of the necessary
documentations, where required, to uplift client held spares.
includes inspection of the safe working zone to ensure this safe
work area has been correctly delineated and provides a safe work
environment.
The work party is fully briefed on the equipment to be worked on, work to be
done, safe working zone and safety features in place, and have signed the
access permit or its approved equivalent. All communication with the work
party is clear and unambiguous.
Range:
includes the ability to resolve any concerns the work party may
have over the isolations and the delineation of the safe work area.
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
element 2
Carry out routine inspections and prescribed diagnostic tests.
performance criteria
2.1
People and equipment are resourced for the required work.
Range:
2.2
Inspection and diagnostic tests are completed in accordance with the selected
procedures.
Range:
2.3
may include but not limited to - people, tools, spares, materials,
‘inspection sheets’, procedure sheets, diagnostic test equipment.
may include but not limited to applying tests in accordance with
IEC 76 or quoted standards for the following items. The deviation
to be less than what the client has prescribed;
windings - resistance of windings, thermometer calibration,
insulation resistance bushing insulation resistance;
cooling system - all pump operation, alarms and settings;
protection - Buchholz relay indications, pressure relief valve,
thermal alarms, oil flow indication, tap change operation, oil
inspection for oil leaks, take oil samples for analysis;
general - check plinth footings.
All diagnostic test results are interpreted and analysed for compliance with
standard.
Range:
may include but not limited to results that are outside of client,
manufacturer or international standards and where corrective
action is required. Interpretation of results may include
recommendations for servicing action.
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
element 3
Carry out servicing.
performance criteria
3.1
All required servicing is carried out consistent with guidelines and procedures.
Range:
3.2
All equipment is reinstated on the transformers.
Range:
3.3
may include but not limited to - all restored equipment is fitted
correctly in the proper order and secured ready for service,
connections tight and electrically correct, oil levels are correct to
level indication.
The on load tap change contacts are serviced.
Range:
3.4
may include but not limited to the following activities - on line oil
filters checked, cleaning ceramic bushings, Buchholz relay
operation checks, replacement of oil pump bearings or unit, fan
motor repairs, remove blockages in oil system, check seismic
constraints are secure, oil treatment and re-testing, tap changer
inspection and oil change.
may include but is not limited to - checking, cleaning, repairing,
replacing.
The on load tap change drive mechanism is serviced.
Range:
may include but is not limited to - checking, cleaning, repairing,
replacing.
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
element 4
Record routine inspection and servicing.
performance criteria
4.1
The ‘as left’ conditions are recorded in the plant history or defect history.
Range:
4.2
may include but not limited to - analysis and reporting of any
defects, correct completion of the plant history, including items
replaced.
The equipment condition status is recorded in accordance with client
requirements.
Range:
may include but not limited to - cyclo recorder, number of trial
operations noted, pressures and auxiliary service quantified,
replacement spares fitted.
element 5
Return equipment to service.
performance criteria
5.1
Work party are withdrawn and warned the equipment is no longer safe to work
on.
Range:
5.2
includes notification to the work party to regard the equipment as
live when they have signed off.
All tools and recipient applied safety measures are removed in accordance with
client requirements.
Range:
includes all access devices, for example, work platforms, scaffold,
‘cherry pickers’.
 New Zealand Qualifications Authority 2016
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ELECTRICITY SUPPLY - POWER
SYSTEM MAINTENANCE
Carry out routine inspection and service
on oil filled distribution power
transformers 11kV to 400V
5.3
All equipment worked on is inspected and set for return to service.
Range:
5.4
includes - confirming all equipment and the work party are clear,
all operational equipment which has been worked on is now set
ready for service.
Returned of access permit, or its approved equivalent, is confirmed.
Range:
includes - confirming all members of the work party have signed
off, the equipment is returned to service without incident.
Comments on this unit standard
Please contact the Electricity Supply Industry Training Organisation ceo@esito.org.nz if
you wish to suggest changes to the content of this unit standard.
Please Note
Providers must be accredited by the Qualifications Authority or a delegated interinstitutional body before they can register credits from assessment against unit standards
or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by the Qualifications Authority before
they can register credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
Accreditation 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 providers wishing to
develop education and training programmes, such as minimum qualifications for tutors and
assessors, and special resource requirements.
This unit standard is covered by AMAP 0120 which can be accessed at
http://www.nzqa.govt.nz/site/framework/search.html.
 New Zealand Qualifications Authority 2016