MT 31 - TC 17/SC 17A/MT 31

IEC 62271-108:2020 applies to high-voltage alternating current disconnecting circuit-breakers for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 52 kV.
This second edition cancels and replaces the first edition published in 2005. This edition contains the following significant technical changes with respect to the previous edition:
- The document has been restructured according to IEC 62271-1:2017.
- The document has been adapted to some of the changes introduced in IEC 62271-100:–[1].
- The document has been adapted to some of the changes introduced in IEC 62271-102:2018.
- References have been reviewed and updated.
- Some definitions have been reviewed and adapted to the latest IEV editions.
- Rated static terminal load and static terminal load test have been removed and a design requirement for static mechanical loads has been included.
- Additional type tests for auxiliary and control circuits have been included.
- X-radiation test procedure for vacuum interrupters has been included.
- Type test for testing of interlocking device and type test for testing of temporary mechanical locking devices have been included.
- Special requirements for making and breaking tests on class E2 disconnecting circuit-breakers have been removed.
[1] Under preparation. Stage at the time of publication: IEC CDV 62271-100:2020.

This part of IEC 62271 applies to high-voltage alternating current disconnecting circuit-breakers for operation at frequencies of 50 Hz and 60 Hz on systems having voltages of 72,5 kV and above. This standard identifies which requirements of IEC 60694, IEC 62271-100 and IEC 62271-102 standards are applicable. It also gives the additional requirements specific to these devices. This standard covers a circuit-breaker which, when in the open position, satisfies the requirements of both a circuit-breaker and a disconnector.