scope:

This part of IEC 62271 is applicable to a.c. circuit-breakers designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1000 V. This technical report addresses utility, consultant and industrial engineers who specify and apply high-voltage circuit-breakers, circuit-breaker development engineers, engineers in testing stations, and engineers who participate in standardization. It is intended to provide background information concerning the facts and figures in the standards and provide a basis for specification for high-voltage circuit-breakers. Thus, its scope will cover the explanation, interpretation and application of IEC 62271-100 and IEC 62271-1 as well as related standards and technical reports with respect to high-voltage circuit-breakers. Rules for circuit-breakers with intentional non-simultaneity between the poles are covered by IEC 62271-302. This technical report does not cover circuit-breakers intended for use on motive power units of electrical traction equipment; these are covered by the IEC 60077 series. Generator circuit-breakers installed between generator and step-up transformer are not within the scope of this technical report. This technical report does not cover self-tripping circuit-breakers with mechanical tripping devices or devices which cannot be made inoperative. Disconnecting circuit-breakers are covered by IEC 62271-108. By-pass switches in parallel with line series capacitors and their protective equipment are not within the scope of this technical report. These are covered by IEC 62271-109 and IEC 60143-2. In addition, special applications (among others parallel switching, delayed current zero crossings) are treated in annexes to this document.