IEC 62271-109:2019 is applicable to AC series capacitor by-pass switches designed for outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 52 kV. It is only applicable to by-pass switches for use in three-phase systems. This document is also applicable to the operating devices of by-pass switches and to their auxiliary equipment. This third edition cancels and replaces the second edition published in 2008 and Amendment 1:2013. This edition constitutes a technical revision. This edition contains the following significant technical changes with respect to the previous edition:
a) the document has been restructured according to edition 2.0 of IEC 62271-1;
b) the rated voltage assignation across the by-pass switch has been aligned to the rule defined in IEC 60143-1;
c) clarification has been given regarding rated continuous current of compensated and uncompensated line;
d) some clarifications have been given following a loss of 'suitable precautions';
e) as per Amendment 2 of IEC 62271-100, the section 'Rated time quantities' has been moved to Clause 6 under 'Time quantities';
f) as per Amendment 2 of IEC 62271-100, the section 'Test for static mechanical loads' have been moved to Clause 6 under 'Static mechanical loads';
g) additional rules have been introduced for vacuum interrupters during impulse tests;
h) additional clarifications have been given regarding the number of reduced impulses during impulse tests;
i) a wider tolerance on the current damping during by-pass making current test-duty has been introduced.