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Level 4
Credits 8
Purpose People credited with this unit standard are able to: prepare for routine service on transmission power transformers above 33kV; carry out routine inspections and diagnostic tests; carry out servicing; record routine inspection and servicing; and return equipment to service.
Subfield Electricity Supply
Domain
Status
Status date
Date version published
Planned review date
Entry information
Electricity Supply - Power System Maintenance
Registered
27 April 1998
20 June 2008
31 December 2009
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 test ; 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
Eng ineers’ 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 power transformers above 33kV normally applied at electricity supply substations.
7 The following terms and abbreviations relate to this unit standard:
IEC = International Electrotechnical Commission
NZECP = New Zealand Electricity Codes of Practice
DGA = Dissolved gas analysis.
Element 1
Prepare for routine service on transmission power transformers above 33kV.
Performance criteria
1.1 The scope of work and equipment is 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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1.2 The anticipated replacement spares are made available in time for the work.
Range may include but is not limited to the completion of the necessary documentations where required to uplift client held spares.
1.3 The equipment is released from operational use.
Range may include but is not limited to the correct and timely completion of all the prescribed equipment release requests.
1.4 The defect history and plant history records are scrutinised for indications of servicing needs.
Range may include but is not limited to
– known defects, operator reports, client special service requests, oil analysis, dissolved gas analysis, thermography tests.
1.5 The required access permit, or recognised equivalent, is received, checked, and signed.
Range 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.
1.6 All safety measures are in place to eliminate, minimise, or control hazards in the permit area.
Range may include but is not limited to
– inspection of the safe working zone to ensure the work area has been correctly delineated and provides a safe work environment, NZECP 34.
1.7 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 approved equivalent. All communication with the work party must be 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 People and equipment are resourced for the required work.
Range may include but is not limited to
– 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 may include but is not limited to applying tests in accordance with
IEC 60076, or quoted standards, for the following items. The deviation to be less than what the client has prescribed. windings
– resistance of windings, insulation resistance, thermal comparison between units; bushings – tap insulation resistance, insulation resistance; cooling system – all pump operating smoothly, controls and indication, fans tested, alarms and settings, thermometer calibration; protection – Buchholz relay indications, pressure relief valve indication, oil hydrogen monitor, oil flow indication, oil sampling for
DGA, moisture and power factor analysis checked; tank – tap change number operations, inspection oil leaks.
2.3 All diagnostic test results are interpreted and analysed for compliance with the standard.
Range may include but is 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.
Element 3
Carry out servicing.
Performance criteria
3.1 All required servicing is carried out consistent with guidelines and procedures.
Range may include but is 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.
3.2 All equipment is reinstated on the 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 are correct to level indication.
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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.
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 are withdrawn and warned the equipment is no longer safe to work on.
Range includes notification to the work party to regard the equipment as live when they have signed off.
5.2 All tools and recipient applied safety measures are removed in accordance with client requirements.
Range includes all access devices
– for example, work platforms, scaffold, barriers, notices, and ‘cherry pickers’.
5.3 All equipment worked on is inspected and set for return to service.
Range includes – confirming all equipment and the work party are clear, all operational equipment which has been worked on is now set ready for service.
5.4 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.
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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 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.
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New Zealand Qualifications Authority 2020