IEC 61467 pdf – Insulators for overhead lines – Insulator strings and sets for lines with a nominal voltage greater than 1 000 V – AC power arc tests

IEC 61467 pdf – Insulators for overhead lines – Insulator strings and sets for lines with a nominal voltage greater than 1 000 V – AC power arc tests
1scope and object
This International Standard applies to insulator strings and sets comprising string insulatorunits of ceramic material， glass or composite material for use on a.c. overhead lines andtraction lines with a nominal voltage above 1 000 v and a frequency between 15 Hz and100 Hz.
This standard also applies to insulator strings or sets of similar design used in substations.
This standard establishes a standard test procedure for power arc tests on insulator sets. ltalso establishes a standard test procedure for power arc tests on short strings.
This standard does not apply to insulator sets mounted on non-metallic poles or towers.
This standard cannot be directly applied to line post insulators or sets，or to insulatingstructures such as braced line-posts, since their mounting arrangement cannot be reproducedby the standard arrangements as described herein. However, this standard can be used as abasis for agreement for tests on such insulators and arrangements.
The object of this standard is
– to define the terms used,
– to prescribe a standard test procedure,
– to prescribe criteria to evaluate the results of the tests.
Power arc tests are not an obligatory element of line insulator specifications.The standardtest procedures and the evaluation criteria described in this standard are intended to providetesting guidance when power arc tests are felt to be necessary. It is not the object of thisstandard to introduce a general obligation to execute these tests.
2Normative references
The following referenced documents are indispensable for the application of this document.For dated references,only the edition cited applies. For undated references, the latest editionof the referenced document (including any amendments) applies.
lEC 60797，Residual strength of string insulator units of glass or ceramic material foroverhead lines after mechanical damage of the dielectric
IEC 60826,Design criteria of overhead transmission lines
3Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Definitions of other terms used in this standard can be found in lEC 60050-471，IEC 60383-1 andIEC 60383-2.
3.1test
one application of the specified test current for the specified duration to the insulator string orset
3.2
test sequence
three successive tests on the same insulator string or set
3.3
test series
a group of test sequences used to characterize the power arc performance of an insulatorstring or set
3.4
per cent initial asymmetry of current
deviation of the current from a symmetrical wave during the first cycle of a power arc
NOTE Per cent initial asymmetry is expressed as a function of the absolute peak value of the current of the firstcycle ( ) divided by the r.m.s.value of the current (y as follows: