L V lt S tAvi Ramdhin, Sales Manager Southern Region, May 2013

Low Voltage SystemsARC Fault ContainmentARC Fault Containment

© BU 3101 Low Voltage SystemsMay 20, 2013 | Slide 1

ARC Fault ContainmentDevelopmentDevelopment

ABB can rely on its experience with approximately 400 internal arcing tests carried out to-datecarried out to date.

As early as 1979, ABB already performed the first internal arcing tests on MNS

Which at that time were still based on the medium-voltage standards VDE 0670 and IEC 60298 as well as the PEHLA standards.

Central importance was pure personnel protection Central importance was pure personnel protection.

The first international standard regarding the performance of internal arcing tests in low-voltage switchgear systems was published in 1996 (IEC 61641 - VDE 0660 Part 500, additional sheet 2)

The aim was to detect the effects of a possible internal arc on the safety of the operating personnelthe operating personnel

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ARC Fault ContainmentReasons to have an internal arc in low voltageReasons to have an internal arc in low-voltage switchgear ?

N l 80% f l t i l id t h l t d i t k iNearly 80% of electrical accidents are human-related mistakes, i.e. Poor Judgement, Familiarity, procedures

Lack of training Lack of training

working under voltage (Fixed Technology) without safety rules

others, i.e. failure of electrical device, i.e. fuses, breakers, etc.

failure of other technical parts

Conductive deposits on isolating supporting elements under unfavorable Conductive deposits on isolating supporting elements under unfavorable environmental conditions.

If the gases and decomposition products resulting from the faults described are capable of b id i th b t t i hb i h ill b fi d ith t i t itibridging the gap between two neighboring phases, an arc will be fired with current intensities of several thousand amperes and temperatures up to 10,000°C. These conditions will result in a strong pressure build up inside the switchgear.

ARC Fault ContainmentIEC 61641 Guide for testing under conditions of arcingIEC 61641 Guide for testing under conditions of arcing due to internal fault:

This technical report applies to enclosed low-voltage switchgear and controlgear assemblies manufactured according to IEC 61439-1. This test is subject to an agreement between manufacturer and user. It is not considered to be a type test

IEC 61641 is a technical report, The sole purpose of this test is to assess the ability to the assembly to limit the risk of personal injury resulting from an internal arcing fault. p j y g g

Target is to check what will happen in the worst case if there is an internal arc inside the switchgear for any reason

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ARC Fault ContainmentPriorities for AFC protectionPriorities for AFC protection

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ARC Fault Containment Internal arc safetyInternal arc safety

ARC proofing almost impossible to achieve ARC proofing almost impossible to achieve

Internal arc safety is divided into 2 types:

personal safety for operators service and maintenance personal safety for operators, service and maintenance personnel

switchgear safety to limit the damages inside the switchgear and restrict the internal arc to certain area -functional compartments

ABB is market leader with MNS for internal arc safety in s a et eade t S o te a a c sa etylow-voltage switchgears:

standard MNS - 690V, 100kA, 300ms

- 400V , 100kA 300ms

ARC Fault ContainmentTest criteriaTest criteria

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ARC Fault ContainmentPoints of IgnitionPoints of Ignition

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ARC Fault Containment Safety PolicySafety PolicyABB Practices the “ ZERO HARM “ policy with the design of MNS...

ARC Fault Containment IEC 61641IEC 61641

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ARC Fault Containment The Test MethodThe Test Method

The test method: The test-method: The short-circuit values will be adjusted directly at the

incoming side of the switchgear, i.e. 690V+10%, 50kAg g

The incoming ACB is mechanically blocked, the current will be not limited and the breaker will not trip during the arc burning timearc burning time additional safety due to high-speed tripping of Emax ACBs

in 30ms,if Icc > Icwif Icc > Icw

normal tripping time of Emax ACBs is maximum 100ms

An arc will be ignited by a short-circuit (bare copper-g y ( ppwire 1.5mm²) at the unprotected side of a functional unit, incoming breaker, main bus, etc.

The high short circuit values will melt the wire and the The high short-circuit values will melt the wire and the arc is ignited

ARC Fault Containment Module TestedModule Tested

!!

8E/4 withdrawable unit with ignition-wire 1,5mm²

t th l idat the supply side

ARC Fault Containment Actual TestActual Test

After 300ms the current will be turned off and the test is complete 300ms arc burning time enables selectivity of incoming

breakers

300ms is the maximum arc burning time in low-voltage switchgears

5 criteria's will be checked after the test, i.e. no doors covers opened no doors, covers opened

no parts, which may cause hazards, flew off

no holes were burned in the enclosure

the operator*) in front of the switchgear in a distance of 300mm will not be seriously harmed

protection earth system is still effective

*) the operator is simulated by a „wall of cotton“ ... The cotton quality is about 150g/m², which is 50% thinner than typical electrician clothestypical electrician clothes

Internal arc safety

Test arrangement, MNS with

tt i di t t iti l lcotton indicators at critical places

Horinzontal indicators are only required in

Vertical cotton indicators

are only required in medium voltage

C tt

Vertical cotton indicators up to 2m height

Cotton indicatorSwitchgearSwitchgear front

Internal arc safety

!!

MNS cubicle after the testMNS cubicle after the test!!

ARC Fault Containment ABB IEC 61641 TestABB IEC 61641 Test

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