14342 version 3
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Carry out routine inspection and minor servicing on high voltage SF6
outdoor circuit breakers
Level
4
Credits
5
Purpose
People credited with this unit standard are able to: prepare for inspection,
testing and servicing on high voltage sulphur hexafloride gas (SF6) outdoor
circuit breakers; make the circuit breaker safe for work; carry out routine
inspections and diagnostic tests; carry out servicing; perform function tests
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
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 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 diagnostic testing and
applying preventative minor servicing and replacement repairs, where necessary, on
high voltage SF6 live tank and dead tank outdoor circuit breakers, and is normally
done at electricity supply substations. Note: Major overhauls of SF6 circuit breakers
are not covered by this unit standard.
7
The following terms and abbreviations relate to this unit standard:
SF6 = Sulphur hexafloride gas
CB = Circuit breaker
PPMV = Parts per million/volume
PPMW = Parts per million/weight
IEC = International Electrotechnical Commission.
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Elements and performance criteria
Element 1
Prepare for inspection, testing and servicing on high voltage SF6 outdoor circuit breakers.
Performance criteria
1.1
The scope of work and equipment to be services is identified from client
requirements.
Range
1.2
Personnel and equipment are resourced for the required work.
Range
1.3
may include but is not limited to associated ‘check and/or
inspection lists’, procedures and client required diagnostic tests
and servicing for – SF6 live tank and dead tank circuit breakers
with hydraulic, motor spring or pneumatic mechanisms.
may include but is not limited to – tools, spares, materials,
‘inspection sheets, procedure sheets.
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 breaker safe for work.
Performance criteria
2.1
The required access permit, or recognised equivalent, is received, checked, and
signed.
Range
2.2
includes a careful check of the isolations to ensure the access
permit or recognised equivalent provides a safe work environment.
Additional isolation from other energy sources on the circuit breaker is applied.
Range
may include but is not limited to – releasing or spragging spring,
closing energy systems, isolating trip and close actuating coils and
motor drive systems, release or isolation of hydraulic or pneumatic
pressure systems, recovery of SF6 gas for storage and/or
treatment.
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2.3
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
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 – storage facilities for gas, safe
work area has been identified and marked, special ventilation.
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
3.2
The inspections carried out identify any damage or defects.
Range
3.3
may include but is not limited to – gas decomposition, relationship
between dew point, ppmv and ppmw, temperature, typical values.
The diagnostic tests are carried out and the results analysed for the interpreting
the servicing required.
Range
3.5
may include but is not limited to – hydraulic oil leaks, signs of
overheating, compressed air leaks, corrosion, porcelain damage.
The SF6 gas tests required are identified and test requirements, including
acceptable values, are explained.
Range
3.4
may include but is not limited to – thermovision test results,
malfunctions, reported problems, SF6 gas leaks.
may include but is not limited to – SF6 gas leak detection,
insulation resistance tests, time travel tests, contact resistance,
timing, minimum operating voltage, alarm hydraulic/pneumatic
pressure settings, pressure vessel inspections, compressor pumpup time, low pressure lock out settings, hydraulic accumulator
recharge pressure.
The results of the diagnostic tests are recorded to meet the client requirements.
Range
may include but is not limited to – completing client or enterprise
check lists, electronic data records, client reports.
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Element 4
Carry out servicing.
Performance criteria
4.1
The SF6 gas recovery and treatment is completed consistent with enterprise or
client requirements.
Range
4.2
may include but is not limited to storage treatment and re-testing
before refilling the circuit breaker.
The major or minor invasive servicing is carried out following enterprise or client
procedures.
Range
may include but is not limited to – SF6 gas filtering and/or top-up,
SF6 gas leaks repaired, mechanism lubrication, corrosion
corrective work, operation adjustments, cleaning ceramic
bushings.
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 – air service, control circuits,
mechanism power and indication.
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 breaker mechanism.
may include but is not limited to – gas decomposition, relationship
between dew point, ppmv and ppmw, temperature, typical values.
All the maintenance tools and facilities are removed and the circuit breaker left
in the ‘ready-for-service’ condition.
Range
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 or maintenance disable switch is correct position.
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5.5
All equipment worked on is inspected and set for return to service.
Range
5.6
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.
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 services
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.
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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