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Carry out routine inspection and servicing on high voltage air blast
circuit breakers
Level
4
Credits
4
Purpose
People credited with this unit standard are able to: prepare for inspection,
testing, and servicing on high voltage air blast circuit breakers; make the
circuit breakers safe for work; carry out routine inspections and diagnostic
tests; carry out servicing; perform function test and pre-service checks; and
complete documentation.
Subfield
Electricity Supply
Domain
Electricity Supply - Power System Maintenance
Status
Registered
Status date
27 April 1998
Date version published
21 November 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 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.
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.
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.
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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 3240.
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 asset owner requirements; manufacturers’
specifications; and enterprise requirements which cover the documented workplace
policies, procedures, specifications, business, and quality management requirements
relevant to the workplace, or training or educational environment in which
assessment is carried out.
5
Core electrical theory is essential knowledge underpinning the performances
required by this unit standard.
6
The range of this unit standard is limited to carrying out diagnostic testing and
applying preventative maintenance and replacement repairs, where necessary, on
high voltage air blast circuit breakers, including indoor and outdoor air blast breakers,
and is normally done at electricity supply substations.
7
The following terms and abbreviations relate to this unit standard:
CB refers to Circuit breaker
Elements and performance criteria
Element 1
Prepare for inspection, testing and servicing on high voltage air blast circuit breakers.
Performance criteria
1.1
The scope of work and equipment to be serviced is identified from client
requirements.
Range
1.2
may include but is not limited to – associated ‘check and/or
inspection lists’, procedures and client required diagnostic tests
and servicing for – indoor and outdoor air blast circuit breakers
with solenoid initiated, pneumatic, pneumatic-hydraulic
mechanisms.
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.
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1.3
The inspection, diagnostic testing, and servicing requirements are interpreted
and analysed for determining the performance and quality standards required.
Range
may include but is not limited to – manufacturer’s guidelines, client
maintenance standards or enterprise guidelines.
Element 2
Make the circuit breakers safe for work.
Performance criteria
2.1
The required access permit, or approved equivalent, is received, checked, and
signed.
Range
2.2
Additional isolation from other energy sources on the circuit breaker is applied.
Range
2.3
may include but is not limited to – removal and draining of high
pressure air, releasing closing energy systems, isolating actuating
trip coils.
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 is clear and unambiguous.
Range
2.4
includes a careful check of the isolations to ensure the access
permit or recognised equivalent provides a safe work environment.
may include but is not limited to the ability to resolve any concerns
the work party may have over the isolations and the delineation of
the safe work area.
Safety measures are available and prepared to protect the environment and
personnel.
Range
may include but is not limited to – hearing protectors, the safe
work area has been identified and marked, air supply values have
been identified.
Element 3
Carry out routine inspections and diagnostic tests.
Performance criteria
3.1
The CB defect history and operational records are scrutinised, and incidents
indicating service needs noted for attention during the routine servicing.
Range
may include but is not limited to – serious fault interruptions,
malfunctions, reported problems, thermovision test results.
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3.2
The inspections carried out identify any damage or defects.
Range
3.3
The diagnostic tests are carried out and the results analysed for interpreting the
servicing required.
Range
3.4
may include but is not limited to – oil leaks, signs of overheating.
may include but is not limited to – pressure vessels inspection,
time travel, contact resistance, timing tests, minimum operating
voltage, alarm and pressure settings, moisture in air tests,
compressor pump up time, check of breather calibration.
The results of the diagnostic tests are recorded to meet the client requirements.
Range
may include but is not limited to – completing enterprise check
lists, electronic data records, client reports.
Element 4
Carry out servicing.
Performance criteria
4.1
Air discharged from tanks is checked for sign of corrosion products.
Range
4.2
The major or minor invasive servicing is carried out.
Range
4.3
may include but is not limited to checking initial discharge for
moisture and discolouration.
may include but is not limited to – replacement at contact buffers,
repair or replacement of worn parts, contact tips are replaced,
cleaning, mechanism lubrication, operation adjustments, corrosion
corrective work, replacement of defective seals, packings,
lubricating valves.
The re-assembly of the circuit breaker is carried out in the approved manner
provided by the maker.
Range
may include but is not limited to – all components being
assembled in the correct order, with proper fit and secured in the
specified way, air replaced into circuit breaker to correct pressure.
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Element 5
Perform function tests and pre-service checks.
Performance criteria
5.1
Work party is advised of a trial operation about to start.
Range
5.2
All services and necessary control features are reinstated and approval
obtained for function tests.
Range
5.3
may include but is not limited to – checking all tools removed, all
connections tight, all panels returned, all valves set to ‘in-service’
position, service/maintenance disable switch in correct position,
CB returned to service.
All equipment worked on is inspected and set for return to service.
Range
5.6
may include but is not limited to – pressure vessels inspection,
time travel, contact resistance, timing tests, minimum operating
voltage, alarm and pressure settings, moisture in air tests,
compressor pump-up time, check of breather calibration.
All the maintenance tools and facilities are removed and the circuit breaker left
in the ‘ready-for-service’ condition.
Range
5.5
may include but is not limited to – air service, control circuits,
mechanism, power and indication, functional tests to include 3ø
trip and close, and phase discrepancy tests.
All the function tests required are completed without malfunction and to
standard.
Range
5.4
may include but is not limited to – checking that people and tools
are all clear of the circuit breakers mechanism.
may include but is not limited to – 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 equivalent, is confirmed.
Range
may include but is not limited to – confirming all members of the
work party have signed off, the equipment is returned to service
without incident.
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Element 6
Complete documentation.
Performance criteria
6.1
The ‘as found’ and ‘as left’ conditions are recorded in the plant history.
Range
6.2
The equipment condition status is recorded.
Range
6.3
may include but is not limited to – analysis and reporting of any
defects, correct completion of the plant and defect history,
including replacement spares fitted.
may include but is not limited to – operation counter noted,
number of trial operations noted, pressures and auxiliary service
quantified.
The routine and inspection service records are completed to meet the client
requirements.
Range
may include but is not limited to written records or electronic data
reporting.
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.
 New Zealand Qualifications Authority 2016