Standards Development

Scope

This technical specification combines the previous IEC TR 61641 and IEC TS 63107 as a common IEC TS and defines the validation of the ability of the PSC-assembly to limit the risk of personal injury, damage of PSC-assembly and its suitability for further service as a result of an internal arcing fault.

This document takes into consideration:

– the effects of the internal overpressure acting on covers, doors, etc.;

– the thermal effects of the arc or its roots on the enclosures and of ejected hot gases and glowing particles.

– the correct function of the IAMS within the PSC-assembly;

– the prevention of unintended operation of the IAMS within the PSC -assembly;

– the functioning behaviour of the system immediately after the PSC -assembly is energised. 

Different tests under more severe conditions (e.g. doors in open position) ca n be performed with an agreement between the user and the original manufacturer of the PSC -assembly.

This document states requirements on the method of testing of PSC -assemblies (power switchgear and controlgear PSC-assemblies) under conditions of arcing in air due to an internal fault with or without the integration of IAMS in low-voltage switchgear and controlgear PSC-assemblies– PSC-assembly according to IEC 61439-1 and IEC 61439-2 (PSC-assemblies).

NOTE This document can be used as a reference for other types of PSC-assemblies in the IEC 61439 series, but adaptation of the test procedures and acceptance criteria can apply taking into account the specifics of such other PSC-assemblies or products. This concerns in particular to BTS according to IEC 61439-6.

This document does not supersede any individual product standard. Individual devices are required to comply with their relevant standard.

This document does not apply to integration of arc fault detection devices (AFDD) according to IEC 62606.

The informative Annex II gives guidance for the user of PSC-assemblies about the criteria to be considered when specifying a PSC-assembly with an integrated IAMS.

The informative Annex JJ gives guidance on particular constructional requirements for incorporati on of IAMS within a PSC-assembly

Purpose

Internal arc-fault protection of power switchgear and controlgear assemblies (PSC-assemblies according to IEC 61439-2) – Applications are subject of the SC121B.

Use of internal arc-fault protection within assemblies are established for many years for foreseen applications. Installation and application is very specific compared with assemblies without the use of arc - fault protection systems. The internal arc-fault is not considered as a normal operating condition. Nevertheless the occurrence of an internal arc cannot completely be excluded. On th e rare occasions that they do occur, typically internal arc faults result from e.g. conducting materials inadvertently left in PSC - assembly during manufacture, installation or maintenance; faults in materials; entry of small animals such as mice, snakes; ...

Due to the risk of personnel injury, damage and loss of energy supply as consequences of arc faults there is a demand for arc fault tested PSC-assembly. This technical specification describes the verification of a PSC-assembly under conditions of arcing in air due to an internal failure without (arc-fault resistant) or with the integration of Internal arc-fault mitigation systems (IAMS).

It is of mutual interest to harmonize definitions, specify the criteria, detail the construction requirements, define the technical characteristics, and provide verifications for Internal arc -fault protection of power switchgear and controlgear assemblies.

The evolution of this technical specification for arc-fault protected PSC-assemblies are considered beneficial to reflect all technical requirements of the previous TR 61641 and TS 63107 in one standard which are covering the same topic.