Committees responsible
National foreword
Introduction
1. Scope and object
2. Normative references
3. Classification of the puncture test on insulators
4. Impulse voltage puncture test on insulators in air
Annexes
A. (normative) Method for determining U50 of the
insulator for the basis of per unit (p.u.) values
B. (informative) Information on measuring short high-
voltage impulses
C. (informative) Test requirements and reproducibility
of the impulse voltage puncture test on insulators
in air
D. (informative) Feasibility of a sample test
E. (informative) Reproducibility of the power frequency
puncture test on insulators in oil
Table
D.1 Total time needed for puncture sample tests in
different cases including preparation and a check
of withstand after the impulse test
Figures
1. Mounting arrangements of cap and pin and long-rod
insulators
2. Mounting arrangements of different pin and line-post
insulators
3. Example of a recommendable configuration of small-
size solid-type voltage divider
4. Example of the applied impulse chopped at the test
voltage by flashover of the insulator
5. Illustration for the per unit values
6. Probability of puncture versus peak voltage of a
lot of insulators tested in five laboratories with
10 positive and 10 negative impulses
7. Amplitude versus steepness of a cap and pin insulator
with a linearity rising negative impulse
8. Examples of different non-linear impulses
9. Domain of steepness (S) versus positive and negative
flashover voltages (U) of cap and pin insulators in
per units as defined in annex A. Results for normal
and anti-fog types, obtained from different
laboratories
10. Results of inter-laboratory comparison of power-
frequency puncture tests on cap and pin insulators
in oil. Mean value of puncture voltages in each
test versus resistivity of the oil
11. Puncture voltage versus oil resistivity for an
insulator with standard and reduced insulation
thickness