BS 7803:1995

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