This standard is applicable to AC circuit breakers designed and installed indoors or outdoors and operating in systems with a frequency of 50Hz and a voltage of 3kV~1000kV. This standard only applies to three-pole circuit breakers in three-phase systems and single-pole circuit breakers in single-phase systems. Two-pole circuit breakers used in single-phase systems and used at frequencies below 50 Hz shall comply with the agreement between the manufacturer and the user. This standard also applies to the operating mechanism of circuit breakers and their auxiliary equipment. However, this standard does not involve circuit breakers that rely solely on manual operation of the closing mechanism, because it cannot specify the rated short-circuit closing current, and from a safety perspective, this method of manual operation alone should not be advocated. For high-voltage AC circuit breakers with predetermined pole-to-pole operation in different periods, see GB/T 30846-2014 "High-voltage AC circuit breaker with predetermined pole-to-pole operation in different periods"; circuit breakers with single-pole automatic reclosing function are included in the scope of this standard . This standard does not cover circuit breakers in mobile power stations for electric traction equipment, they are covered by IEC 60077. Generator circuit breakers installed between the generator and the step-up transformer are also outside the scope of this standard. Inductive load switching is included in GB/T 29489-2013 "Inductive load switching of high-voltage AC switchgear and control equipment". Self-tripping circuit breakers with mechanical tripping devices or devices that cannot fail may refer to this standard. Circuit breakers used as bypass switches in parallel with line series capacitors and their protective equipment are not included in the scope of this standard. They are included in GB/T 28565-2012 "Bypass switches for high-voltage AC series capacitors" and IEC 60143-2 .
DL/T 402-2016 Referenced Document
GB 2536-2011 Fluids for electrotechnical applications.Unused mineral insulating oils for transformers and switchgear
GB 4208-2008 Degrees of protection provided by enclosure(IP code)
GB 7674-2008 Gas-insulated metal-enclosed switchgear for rated voltages of 72.5kV and above