Tracking & Erosión
2017-12-08
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TRACKING AND EROSION TESTS APPLIED TO
POLYMER INSULATORS
Based on the extended use of polymer insulators in various applications and installation conditions
throughout the world’s electric distribution and transmission networks, and on mandatory fulfillment
of technical requirements associated with the use of this type of products, it is important to be clear
on certain key points related to the international standard IEC 62217, which applies to polymer
insulators with a rated voltage above 1,000V.
“The author thanks the International Electrotechnical Commission (IEC) for permission to reproduce Information from its
International Standards IEC/TR 62730 ed.1.0 (2012) and IEC 62217 ed.2.0 (2012).
All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved. Further information on the IEC is available from
www.iec.ch. IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by the author,
nor is IEC in any way responsible for the other content or accuracy therein”
Nota:
Technical Bulletin May 30th - 2016
TECHNICAL BULLETIN
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 11 - 3.8
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 11 - 3.9
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 12 - 4.1
IEC/TR 62730 ed.1.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
IEC 62217 ed.2.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
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TRACKING:
FURROWS THAT APPEAR AND GROW ON THE
SURFACE OF THE INSULATING MATERIAL.
THESE TRACKS ARE CONDUCTIVE EVEN
WHEN DRY.
One topic in particular raises controversy
among technical experts and specialized
personnel dedicated to generating
specifications for this type of product within
energy companies, and that is the tests for
Tracking (formation of conductive tracks) and
Erosion.
To better understand this type of test and
subsequent updates related to the standard, it
is necessary to be clear about the dierences
between these and accelerated aging tests.
First, the tracking and erosion test must not in
any way be confused with the accelerated
aging test. According to IEC 62217 2nd Edition
(Appendix A, this type of test must not be
confused because the tracking and erosion test
does not precisely simulate the degradation to
which an insulator is subjected under actual
conditions, nor is it intended to simulate the
degradation conditions to which the insulator
is subjected over a short period of time during
its useful life.
Tracking: The formation of conductive tracks is
a process that produces irreversible
degradation due to the formation of
conductive tracks (or furrows) that appear and
grow on the surface of the insulating material.
These tracks are conductive even when dry.'
Erosion: Irreversible non-conductive
degradation that can occur on the surface of
the insulator due to material loss. It may be
uniform, localized, or arborescent.
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Instead, this type of test is intended to subject
the insulator to continuous stress, attempting
to detect potential weaknesses in both material
and design that could compromise the
insulator’s performance under service
conditions. This test is therefore a tool that can
be used to reject materials or designs that
could be inadequate for the installed
conditions.
In the case of polymer insulators, aging tests
generally do not cause a progressive decrease
of any easily measurable property related to
usage time. The insulator’s transition from
good condition to its end-of-life condition
usually occurs rapidly and without warning.
GAMMA Insulators
The time and speed of the transition depend on
a variety of parameters, including the insulator
and its design as well as the environment.
These degradation tests are only applicable
and really relevant when conditions truly match
the insulator’s actual installed conditions.
According to the changes introduced in the
second and most recent version of IEC
standard 62217 in 2012, concerning tracking
and erosion tests, it is important to mention
that, although the first edition of this standard
included 2 alternate tests (the 5000-hour
multi-stress test and the wheel test), these are
no longer listed as such in the latest edition,
pursuant to the results provided by Technical
Committee No. 36 (TC 36) based on the latest
studies conducted by that committee and
which can be consulted in the 2012 test report
TR 62730.
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 12 - 4.1
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 12 - 4.1
IEC/TR 62730 ed.1.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
IEC 62217 ed.2.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
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TECHNICAL BULLETIN
SOME
CONCLUSIONS
FROM THE STUDY
AND TECHNICAL
REPORT TR62730
GAMMA Insulators
IEC 62217, “Polymeric HV insulators for indoor and outdoor use - General definitions, test methods and acceptance criteria”, 2012.
IEC/TR 62730, “HV polymeric insulators for indoor and outdoor use tracking and erosion testing by wheel test and 5 000h test,” 2012. p 9.
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GAMMA Insulators Corp.
According to the 2012 test report TR 62730
issued by the technical committee TC 36, the
1.000-hour test was adopted as the only
standardized test in the new version of IEC
622175 in 2012.
One of the primary objectives of the technical
report TR 62730 presented by the committee
TC 36 is to explain the background behind the
development and use of the 5.000-hour
multiple-stress and wheel tests, describing the
test methods, sample conditions, procedures
for both tests, and acceptance and rejection
criteria.
Pursuant to the decision of the committee TC
36, which indicated that it was desirable to
have a single standardized tracking and
erosion test in IEC 62217, studies were
conducted on the use and ecacy of the 3
tests mentioned in the first version of the
standard.
These studies indicated that, although both the
5.000-hour and wheel tests had some
advantages, only the 1.000-hour saline mist
test was adapted to all types of insulators and
was more economical to conduct.6 It was also
discerning enough to adequately test this type
of insulator.
The report further states that both the
5000-hour and wheel tests were used as
alternate or supplemental tests to the
1.000-hour saline mist test, but in no case
could be considered accelerated aging tests,
where in particular the 5.000-hour test had
reproducibility problems.
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IEC/TR 62730 ed.1.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
IEC 62217 ed.2.0 “Copyright © 2012 IEC Geneva, Switzerland. www.iec.ch”
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www.gammainsulators.com
GAMMA INSULATORS
CRA 49 N. 67 SUR 680
SABANETA - COLOMBIA - SOUTH AMERICA
TELEPHON: (574) 3058000
