Frankfurt (Germany), 6-9 June 2011
Session 1 – Roundtable C:
Internal Arc Classification –
How to convert test results into Personal
Safety on Site
Convenor:
Uwe KALTENBORN
Schneider Electric, Germany
Panelists:
Jean-Marc Biasse
Harm Bannink
Peter Beer
Jose-Manuel Inchausti
Gerard Schoonenberg
Carlo Gemme
Thomas Reiher
IEC SC 17C, France
KEMA, The Netherlands
PEHLA, Germany
Ormazabal, Spain
Eaton, The Netherlands
ABB, Italy
Siemens, Germany
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Structure of Roundtable
1. Introduction of key topics
5 min
2. Overview of relevant papers in Session 1
4 min
3. Introduction of all panelist with their key topic
7x5 min
4. Discussion
45 min
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Introduction of Session 1 papers
1170: DEVELOPMENTS FOR MAXIMUM SAFETY IN MEDIUM
VOLTAGE SUBSTATIONS REGARDING INTERNAL ARCS
Paper 1170 provides a good review of the internal arc protection topic in MV
switchgear and substations. The evolution of IEC standards in this respect is
presented. Some test results are also given for testing according to
conditions newly defined in the next edition of IEC 62271-200 (single phase
to earth fault) and also in conditions not covered by the standards (e.g. open
compartment).
1137: SOLUTIONS FOR INTERNAL ARC PROTECTION ACC. IEC
62271-200 WITH PRESSURE RELIEF INTO THE SWITCHGEAR
ROOM FOR AIS and GIS
Paper 1137 presents solutions developed for reducing overpressure inside
the switchgear room in case of internal arc, when exhaust ducts to the
outside of the room are not possible. Suitable arc energy absorbers have
been found effective in reducing the temperature of the exhaust gases and
the pressure rise in the room: their adaptation to two types of MV switchgear
(air insulated and gas insulated) is described.
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Introduction of Session 1 papers
0385: SOLUTION FOR INTERNAL ARC FLASH HAZARDS IN AIS
Another, and possibly complementary, approach is presented in paper 385
which describes an active arc protection system. It consists in arc sensors
(light and current), in a specific arc protection relay with a short operating
time of 2.5 ms, and a fast acting earthing switch driven by a Thomson coil
mechanism (closing time 3.5 ms). It is thus possible to short-circuit the arc
in less than 10 ms, and in this way to reduce a lot the dangerous effects of
the arc fault, compared to a fast acting protection by a 3-cycles (50 ms at 60
Hz) circuit-breaker.
1326: SIMPLIFIED INTERNAL ARC-STRUCTURAL SIMULATION
In paper 1326 are reported some advances in internal arc simulation for
pressure rise and structural response in the compartments subjected to an
internal arc. Although simplified, the proposed method does not need to use
an empiric energy transfer factor (that can vary from one configuration to
another) as an adjustable parameter, and shows good agreement between
calculations and test results.
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
IEC standards were developed in the past
years to provide more safety
Among safety aspects, optional performance to
withstand internal has been introduced in IEC
60298
 It was a first step but not sufficient




« Test procedure to be agreed between manufacturer
and user » may lead to endless discussion
Annex AA already normative but not precise enough
Approach more adapted to specific projects than to
repetitive MV products
JM Biasse – France – RT Internal arc
Frankfurt (Germany), 6-9 June 2011
IEC 62271-200 Ed 1.0 2003 brought a
breakthrough
First protection is to prevent internal fault
occurrence by proper design
 Among other methods, IAC contributes to
internal arc protection
 Internal Arc classification defined and optionnal
 Internal arc test becomes a type test (optionnal)
 Tests have to be done in every MV compartment
to claim for internal arc withstand.

JM Biasse – France – RT Internal arc
Frankfurt (Germany), 6-9 June 2011
Future IEC 62271-200 Ed 2.0 (2011) will
be more precise
Internal arc performance still optional
 Still focused on safety for individuals
 Criteria to pass the test will be in the main text
 Annex is now only relevant for test labs
 Test procedure better defined on several points

JM Biasse – France – RT Internal arc
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Internal Arc Testing




Performing between 80 – 100 internal arc tests per year
Requests for testing is rising
Approx. 20% of all internal arc test objects do not pass, mostly
because of ignition of indicators
Certification now considered in
STL (Short-circuit
Testing Liaison)
Replacing SF6 insulation by air
in testing is still under discussion
CIGRE is working on Technical
Brochure on modelling of
internal arc effects
100%
not fulfilled
fulfilled
80%
60%

40%
20%

0%
1
H. Bannink – Netherlands – RT S1c
2
3
4
5
c riterium as s pec ified in IE C 62271-200 A 6
total res ult
Frankfurt (Germany), 6-9 June 2011
Neutral treatment during IA testing


IEC states lab grounding of enclosure is the most severe situation
IEEE states extended neutral is most severe situation
1.8
enclosure to
lab ground only


Dedicated tests show that in balanced
three phase test circuits there is
almost no current in the extended neutral
Pressure rise in both neutral situations is
almost identical
pressure (b), current (100 kA)
1.6
extended neutral
1.4
1.2
1
0.8
0.6
0.4
current
0.2
0
260
H. Bannink – Netherlands – RT S1c
280
300
320
340
time (ms)
360
380
Frankfurt (Germany), 6-9 June 2011
Importance of proper supply voltage
24 kV supply voltage
6 kV supply voltage
40


Tests should be performed with
sufficient supply voltage (close to
rated voltage) in order to create
stresses equal to the service
situation.
At supply voltage much lower
than rated, the effect of arc
voltage on current asymmetry
becomes too strong
Internal pressure rise with low
supply voltage is too low, even
though RMS current is identical
H. Bannink – Netherlands – RT S1c
30
20
10
0
-10
-20
300
350
400
450
500
550
1.8
pressure (b), current (100 kA)

24 kV supply voltage
1.6
1.4
6 kV supply voltage
1.2
1
0.8
0.6
0.4
0.2
0
260
280
300
320
340
time (ms)
360
380
600
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Test Execution according
IEC 62271-200/FDIS-Ed2

Strengthening of the normative Character by integration of the
IAC tests in the main text (§6.106)

Appendix AA contains directives for performing the tests, as room
simulation, indicators, calibration of the test values

Optional: IAC-classification “IACe” for single pole compartment


Ignition only conductor to earth with smaller current IAe

if neighbour conductor is damaged => repetition of 3 phase test with
IA
Criteria 2

Parts > 60g between panels and indicator frame are
down (e.g. a plugged operating lever)
Peter Beer – Germany – RT1c – Paper ID
allowed to fall
Frankfurt (Germany), 6-9 June 2011
Test Execution according
IEC 62271-200/FDIS-Ed2



Minimum distance to ceiling according
manufacturer instruction
Test result is than also valid for larger
distances of the ceiling
Distances to the ceiling < 20cm
indicate a separate testing
*Test for accessible rear side is valid also for
installation directly to the wall with distance 30
cm / 10 cm distance to the wall, which means
distance to indicator frame
(30cm/10cm = accessibility A/B)
Peter Beer – Germany – RT1c – Paper ID
Manufacturer
instruction
10 cm
or
80* cm
10 cm
Operating side
supply
Frankfurt (Germany), 6-9 June 2011
Test Execution according
IEC 62271-200/FDIS-Ed2





as a basic principle no new requirements or higher test
values
test results according edition 1, IEC 62271-200 keep valid
correction of formal or editorial inconsistencies
IAC qualification more significantly integrated into the Type
Tests
 test requirement more related to practice
Time Schedule:
 FDIS
“12/2010”
 Edition 2 middle of 2011
Peter Beer – Germany – RT1c – Paper ID
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Arc protection design on IEC 62271-200





Standardised characteristics and tests are oriented to reduce to a
minimum the probability of arc fault on GIS.
Metallic envelope offers protection to the people, among others
against internal arc fault; when declared by the manufacturer.
Standardised way of declaration of internal arc fault protection is IAC
classification.
Currently one value of arc current and one arc duration can be
declared per switchgear.
Elements that may be outside the metallic envelope like busbars or
cables are not considered by IAC classification.
J.M.Inchausti – Spain – RT S1c
Frankfurt (Germany), 6-9 June 2011
Arc protection design on IEC 62271-200



LSC classification is not related with IAC classification, but more
compartments are present on a GIS, less parts are affected by the
arc fault and more type tests have to be performed to obtain IAC
classification (one test per compartment).
Use of short-circuit current limiters (fuses or circuit-breakers) may
reduce arc current value and/or arc duration for the IAC declaration.
Active protection systems based on internal short-circuiting devices
to reduce the duration of the arc fault and its consequences are not
free to be at the origin of an arc fault and therefore IAC classification
only considers the tested actual duration of the arc.
J.M.Inchausti – Spain – RT S1c
Frankfurt (Germany), 6-9 June 2011
Arc protection design on IEC 62271-200



Solid insulation on GIS may reduce the number of parts affected by
an arc fault or limit this to a phase-to-earth or two-phases arc fault.
This situation is not correctly addressed by current standard.
Internal arc protection design should consider geometry, materials
involved and evolution of an eventual arc inside each compartment.
Proper design will lead the arc to a place protected against the
thermal action of the arc.
Hot gases produced by decomposition of insulating solid, liquid or
gas by the action of the arc shall be driven and or cooled to avoid
any damage on the people in close proximity to the switchgear when
an arc fault is produced. Therefore evacuation of these gases is
considered by the standard.
J.M.Inchausti – Spain – RT S1c
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Frankfurt (Germany), 6-9 June 2011
Frankfurt (Germany), 6-9 June 2011
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Active Internal Arc fault protection – measures recommended
by IEC62271-200
Will you drive a car without airbag and
servobrakes?
 Active protection


Passive protection
Carlo Gemme – Italy – RT1c
Frankfurt (Germany), 6-9 June 2011
Conventional protection relay
Dramatic consequences
Fire/Explosion hazard
(heavy injuries of personnel)
Fast protection relay
Limited consequences
for equipment and
personnel
Ultra Fast Earthing
prevention of thermal damage
reduced pressure rise
Carlo Gemme – Italy – RT1c
Steel fire
Copper
fire
Cable fire
Frankfurt (Germany), 6-9 June 2011
Ultra Fast Earthing Switch
 Fast fault detection by Arc protection relay
(<1ms), light & current rise detection
 Ultra-fast extinction of the internal arc by
diverting it to metallic short circuit (<4 ms),
 Final clearing of the fault current by the
upstream circuit-breaker
Carlo Gemme – Italy – RT1c

Metal particles

Cable floor
deformation
Frankfurt (Germany), 6-9 June 2011
Introduction of Key Topics
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc
Frankfurt (Germany), 6-9 June 2011
Arc Fault Pressure Simulation for Switchgear Buildings by
CFD
Preliminary considerations
•
•
•
•
•
arc fault because of short-circuit in a switchgear
high energy explosion in some milliseconds
power peaks up to 100 MW
the result is a conducting insulating distance
free burning high alternating current arc fault
Example:
Switchgear
12 kV / 50 kA
Arc fault energy
7,83 MWs = 2,2 kWh
Power
200 MW at 9 ms
Pressure Peak
1,1 bar at 8,8 ms
Face pressure
of panel parts
 10 t / m²
REIHER – DE – RT-S1c– Paper ID
copyright: TÜV Rheinland / Berlin-Brandenburg
Schutzseminar 2002
Frankfurt (Germany), 6-9 June 2011
Arc Fault Pressure Simulation for Switchgear Buildings by
CFD
Average pressure Pigler (1976)
Following criteria missing:
•
no switch gear corpus/absorber
•
no flow blockages in the room
•
location of pressure relief openings
•
geometry of the room
•
dynamic processes as reflection,
diffraction, interference neglected
•
pulsing arc fault power assumed constant
•
This approach is only a rough estimation of the pressure rise
•
For closed rooms and if the room is filled with pressure permanent (small rooms), this
approach is a good estimation
REIHER – DE – RT-S1c– Paper ID
Frankfurt (Germany), 6-9 June 2011
Arc Fault Pressure Simulation for Switchgear Buildings by
CFD
3D-Finite Elemente Approach
•
The 3-D finite element CFD method solves in
spatial
variables the pressure on all room walls and
the fluid flow
•
The pressure relief openings are considered
at their
locations and have the correct dimensions
•
The room can be evaluated by the calculated
pressure
according to the given pressure relief opening
•
In the case of too high pressure the pressure
must
be reevaluated for a bigger relief opening
•
In the openings the velocity can be evaluated
and the volume flow
over time can be determined
REIHER – DE – RT-S1c– Paper ID
Frankfurt (Germany), 6-9 June 2011
Key Topics for Discussion
1. Jean Marc Biasse:
Evolutions of IEC 62271-200 on internal fault topic
2. Harm Bannink: Definition of correct test circuits for IEC 62271-200
3. Peter Beer: Test Execution according 62271-200
4. Jose Inchausti:
Design of Gas Insulated Switchgear in accordance with 62271-200
5. Gerard Schoonenberg:
Solid Insulated Switchgear and their interaction with internal arc
6. Carlo Gemme:
Active Internal Arc fault protection
7. Thomas Reiher:
Utilisation of Test-Results for the Simulation of the Internal Arc
Behaviour of Switchgear in Buildings
Session 1 – Roundtable C – Internal Arc