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Carry out routine service on transmission instrument transformers 33kV
and above
Level
4
Credits
7
Purpose
People credited with this unit standard are able to: prepare for routine service
on transmission instrument transformers 33kV and above; carry out routine
inspection and diagnostic checks; carry out servicing; record routine
inspection and servicing; and return equipment to service.
Subfield
Electricity Supply
Domain
Electricity Supply - Power System Maintenance
Status
Registered
Status date
27 April 1998
Date version published
20 June 2008
Planned review date
31 December 2009
Entry information
Prerequisites: Unit 14287, Use and maintain test
instruments used within the high voltage electrical
industry; Unit 14294, Carry out insulating oil sampling
and voltage breakdown tests; Unit 14700, Apply and
remove safety measures in an electricity supply
environment; Unit 14701, Manage electricity supply work
control systems; 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
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
Electricity Supply Industry Training Organisation
Accreditation and Moderation Action Plan (AMAP) reference
0120
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
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Special notes
1
This unit standard can be assessed against 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 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 Safety Manual – Electricity Industry (SM-EI) (2004) 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.
3
The phrase in accordance with industry requirements is implicit in all elements and
performance criteria in this unit standard.
4
‘Industry requirements’ include all industry and workplace documented policies,
procedures, specifications, and business and quality management relevant to the
workplace where assessment is carried out.
5
All work practices shall meet documented enterprise maintenance standards,
including the quality management requirements, and the documentation of activities,
events, and decisions.
6
The range of this unit standard is limited to carrying out preventative maintenance
and replacement and/or repairs to transmission instrument transformers 33kV and
above, normally applied at electricity supply substations.
7
The following terms and abbreviations relate to this unit standard:
CTs = Current transformers
VTs = Voltage transformers
DGA = Dissolved gas analysis.
Elements and performance criteria
Element 1
Prepare for routine service on transmission instrument transformers 33kV and above.
Performance criteria
1.1
The scope of work and equipment is identified.
Range
may include but is not limited to associated client or enterprise
‘check and/or inspection lists’ and procedures for – instrument
transformers, CTs, VTs.
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1.2
The anticipated replacement spares are made available in time for doing the
work.
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
inspection reports, client special service requests, oil analysis,
dissolved gas analysis, thermography tests.
The required access permit, or recognised equivalent, is received, checked, and
signed.
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 requirements.
Range
1.5
may include but is not limited to the necessary documentations
where required to uplift client held spares.
includes inspection of the safe working zone to ensure the 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 has signed the
access permit or its recognised 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.
Element 2
Carry out routine inspections and diagnostic tests.
Performance criteria
2.1
Personnel and equipment are resourced for the required work.
Range
may include but is not limited to – people, tools, spares, materials,
‘inspection sheets’, procedure sheets, diagnostic test equipment.
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2.2
Inspection and diagnostic tests are completed in accordance with the selected
procedures.
Range
2.3
may include but is not limited to – resistance injection tests,
insulation resistance, impedance tests, thermal comparison
between units, oil DGA, capacitance divider checks, gas quality
tests.
All diagnostic test results are interpreted and analysed for compliance with
standard.
Range
may include but is not limited to results that are outside of
enterprise, client, or international standards and where corrective
action is required. Interpretation of results may include
recommendations for servicing action.
Element 3
Carry out servicing.
Performance criteria
3.1
All required servicing is carried out consistent with guidelines and procedures.
Range
3.2
may include but is not limited to – cleaning ceramic bushings, oil
replace or top-up, terminal connections checked, seismic
constraints are secure.
All equipment is reinstated on the instrument transformers.
Range
may include but is 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 or gas pressure
are to required levels.
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
may include but is not limited to – analysis and reporting of any
defects; correct completion of the plant history, including items
replaced.
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4.2
The equipment condition status is recorded in accordance with client
requirements.
Range
may include but is 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 is withdrawn and warned the equipment is no longer safe to work
on.
Range
5.2
All tools and recipient applied safety measures are removed in accordance with
client requirements.
Range
5.3
includes all access devices; for example, work platforms, scaffold,
‘cherry pickers’.
All equipment worked on is inspected and set for return to service.
Range
5.4
includes notification to the work party to regard the equipment as
live when they have signed off.
includes confirming all equipment and the work party are clear, all
operational equipment which has been worked on is now set ready
for service.
Return 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.
Please note
Providers must be 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.
Industry Training Organisations must be accredited by NZQA 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 organisations
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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 info@esito.org.nz if
you wish to suggest changes to the content of this unit standard.
 New Zealand Qualifications Authority 2016