SLIDE 1
EP SERVICE, 2017
ArcLimiterTM
Arc flash mitigation solution for low voltage equipment using UFES
Internal arc faults Ultra-fast eart hing switch (UFES) ArcLimiterTM
April 19, 2017
Slide 2
Index Internal arc faults Ultra-fast eart hing switch (UFES) - - PowerPoint PPT Presentation
Index Internal arc faults Ultra-fast eart hing switch (UFES) - - PowerPoint PPT Presentation
EP SERVICE, 2017 ArcLimiter TM Arc flash mitigation solution for low voltage equipment using UFES Index Internal arc faults Ultra-fast eart hing switch (UFES) ArcLimiter TM Slide 2 April 19, 2017 Internal arc faults Reasons of formation 1.
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SLIDE 3
Reasons of formation
Internal arc faults
April 19, 2017
Slide 3
- 1. Human errors
- 2. Pollution
- 3. Animals
- 4. Overvoltage
- 5. Bad connections
- 6. Mechanical faults
- 7. Defective devices
(e.g., voltage transformer)
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When do they occur?
Internal arc faults
April 19, 2017
Slide 4
Without
- perator,
25% With operator in front of a closed door, 10% With operator working in the switchgear, 65%
“One large utility has discovered an average of 1 arc flash injury every 18 months for the past 54 years.”
(IEEE Std 1584 – 2002, 10.3)
SLIDE 5
Fault characteristics
Internal arc faults
April 19, 2017
Slide 5
An arc arises when at least part of the current passes through a dielectric, usually air Maximum peak power up to 40 MW Arc temperature up to five times the surface temperature of the sun (20,000°C) Light intensity more than 2,000 times that of normal office light
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Industry recognition of arc flash hazard categories
Internal arc faults
April 19, 2017
Slide 6
IEEE 1584-2002, “Guide for Arc Flash Hazard Analysis” NFPA 70E-2009, “Standard for Electrical Safety in the Workplace” The arc flash boundary is required to be calculated by NFPA 70E. Only qualified personnel with appropriate PPE are allowed to enter boundary. Minimum level of Personal Protective Equipment as evaluated in IEEE Standard 1584 to protect workers.
SLIDE 7
Know your incident energies
Internal arc faults
April 19, 2017
Slide 7
Determined after short circuit coordination and arc flash study High incident energies can lead to: – Undesirable and costly changes in operation – Cumbersome PPE requirements – Loss of production due to shutdown requirements
SLIDE 8
Impacts without fault limitation
Internal arc faults
May 9, 2017
Slide 8
§ Circuit breaker
compartment after internal arc impact
§ Cable connection
compartment after internal arc impact
§ Contact terminal
after internal arc impact
SLIDE 9
The basis for effective protection
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 9
Electronic tripping unit – Fast and reliable interface to external arc detection systems – Tripping of the UFES primary switching elements 3 Primary switching elements – Ultra-fast initiation of a 3-phase short-circuit earthing after detection of a fault by the electronics – Elimination of the arc by resulting breakdown
- f the internal arc voltage
UFES wit h elect ronic t ripping unit t ype QRU100
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Sequence of tripping operation
Ultra-fast earthing switch (UFES)
April 19, 2017
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UFES electronic QRU100 features
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 11
Electronic tripping unit Fully compatible with the ABB arc protection system of type REA 2 Optolink inputs for connection of the REA101 relay 2 high-speed inputs (HSI) for connection of external arc detection systems Self monitoring including the Optolink connection to the REA system Logical combination of the external detection units by use of DIP-switches Testing mode for functional check Versatile monitoring options with REA system
Elect ronic t ripping unit t ype QRU100
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Primary switching element
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 12 1 2 3 4 5 6 7 8 9
Primary switching element type U1 Vacuum interrupter and operating system integrated in one compact unit Fast and reliable micro gas generator operating mechanism Fast switching time of ~ 1.5 ms Easy handling Low-maintenance Flexible installation
6.
Piston
7.
Cylinder
8.
Moving cont act syst em
9.
Micro gas generat or
1.
Epoxy insulator
2.
Fixed cont act
3.
Ceramic insulator
4.
Moving cont act pin
5.
Rupture joint Primary switching element – section view
SLIDE 13
Speed differentiation
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 13 Warc [kVAs]*
* Const ant arc volt age & fault current for t he complet e fault time Uarc · Ik · t = Warc (linear funct ion)
Time in ms
Steel fire Copper fire Cable fire
Fast protection relay
- Limit ed consequences
for equipment and personnel (depending on switchgear design) Conventional protection device
- Dramatic consequences possible
- Fire/ Explosion
hazard, heavy injuries of personnel (depending on switchgear design) Ultra-Fast Earthing Switch type UFES
§ Drast ic reduct ion
- f t hermal damages
§ Drast ically reduced pressure rise § No consequences to be expected !
SLIDE 14
Speed and safety – pressure curves
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 14 Example pressure curve, with and without UFES, in a compartment of an air insulated medium voltage switchgear, for an internal arc fault current of 130 kA (peak) / 50 kA (rms)
Overpressure in bar 1 bar = 14.7 psi Pressure rise wit hout UFES Pressure rise wit h UFES Reaching time for t ripping criteria
t TC
Time in ms
t TC + ≤ 4 ms
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Comparison
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 15
Busbar compartment after internal arc impact with active UFES protection Busbar compartment after internal arc impact without active UFES protection (50 kA / 100 ms)
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Available as…
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 16
UFES in a Service Box for top or side mounting UFES as load break switch retrofit Integration in non-ABB switchgear (e.g. Siemens)
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Combinable arc protection by ABB
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 17
UFES + REA Versatile monitoring options with REA system: – Optical detection via line or lens sensors – Overcurrent detection – Selective protection – Circuit-breaker failure protection Ultra-fast arc extinction by UFES Certified interfaces Extremely short tripping times < 4 ms (after detection)
Combinable arc prot ection UFES + REA
+
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Unbeatable advantages
Ultra-fast earthing switch (UFES)
April 19, 2017
Slide 18
Indirect benefit Greatly increased system and process availability by avoidance of heavy damages inside the switchgear, of the equipment and the direct environment Drastic reduction of downtimes and repair costs Direct benefit Greatly increased operator safety for switchgears Minimization of pressure rise and gases in the faulty compartment and surrounding switchgear building
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Application example
ArcLimiterTM
April 19, 2017
Slide 19
ABB testing on LV system shows that even with 60 kA available, incident energy can be reduced to under 1 cal/ cm2 Result is hazard risk category (HRC) zero. MV to LV transformers protected by either:
- MV circuit breaker with protective relays
- A load interrupter fused switch.
With ultra fast grounding system operating in 4 milliseconds, the magnitude of the LV fault level becomes a secondary consideration. Operating speed becomes the critical parameter.
MV BKR UFES
50 51
MV “E” RATED FUSE DT XFMR DT XFMR MV BUS
N/A SYSTEM APPLICABLE SYSTEM
LV BUS LV BUS
ArcLimiterTM tested system
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Test of UFES grounding system
ArcLimiterTM
May 9, 2017
Slide 20
LV circuit breaker compartment before (LEFT) and after (RIGHT) initiation of a 60 kA arc
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Test of UFES grounding system
ArcLimiterTM
April 19, 2017
Slide 21
Test without UFES Test with UFES (arc initiated while breaker is being racked in)
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