Transcript Arc-Flash - Littelfuse

LITTELFUSE
STARTCO
Littelfuse Startco
Arc Flash Relay
PGR-8800
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Arc Faults: Costly and Dangerous
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Dangers
 Fires
 Burns
 Injury
 Death
Costs
 Collateral
damage
 Equipment
replacement
 Downtime
 Labour
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Arc Flash / Blast Statistics
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 Over 1000 people die each year from electrical accidents*
 Up to 10 Arc-Flash incidents occur each day in the US
 Over 2000 workers are sent to burn centers each year with
severe Arc-Flash burns.
 OSHA states that 80% of electrically related accidents and
fatalities among Qualified Workers are caused by ArcFlash/Arc-Blast Incidents.
* Source: National Safety Council
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Case Study – Nov 12, 2009
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 Chiller Easton Ice Rink, Columbus, Ohio
 An electrician was working on a 480V power panel
when the panel sparked and caught fire
– The electrician was thrown to the floor and eventually
transported to the OSU Burn Center with severe burns on
face and hands.
– Witnesses reported the panel was still sparking when the fire
crews arrived.
* Source: Dayton Daily News
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Types of Electrical Hazards
 Electric Shock - trauma caused by the passage
of electric current through the body.
 Arc-Flash – an unexpected sudden release of
intense heat and light energy produced by
electricity traveling through air, usually caused by
accidental contact between live conductors.
 Arc-Blast - a pressure wave created by heating,
melting, vaporization, and expansion of
conducting material and surrounding air during
an Arc-Flash.
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Types of Electrical Hazards
Shock
Fire
Arc-Flash
Light
Sound
Arc-Blast
Gases
Pressure Wave
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Effects of Electrical Hazards on Workers
 Severe burns
 Vision damage or
blindness
 Hearing loss
 Broken bones or internal
organ damage
 Whiplash
 Brain injuries
 Lacerations
 Fatality
Photos courtesy of OSHA
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Effects of Electrical Hazards on Business
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Costly Damage…
 Equipment replacement
and need for capital
 Equipment repair costs
 Downtime
 Production Loss (scrap)
Image from IEEE Electrical Safety Workshop, Floyd, Doan, Barrios, Wellman
…and business
interruption.
Image from IEEE Electrical Safety Workshop, H. Landis Floyd, II
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What Determines Arc-Flash Severity?
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 System Voltage
 Arc Characteristics
– Arc gap / Distance from arc
 Fault Current
– Available fault current
– Arc current typically 38% of
available fault current
Image from OSHA Office of Training & Education
 Time
– Clearing time
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Initiators of these faults

IEEE Std 493-1997 (Gold Book)
Recommended Practice for the Design of
Reliable Industrial and Commercial Power
Systems
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Development of an Arc Fault
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 Voltage difference between two conductors (250V) separated by air
gap, high resistance
 Voltage reaches breakdown point, rapid release of energy across gap
 Shortest distance from bus bar corner to bolt corner
• Usually phase-to-phase or phase-to-ground
• Energy limited only by system resistance, air gap impedance
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Lifespan of an Arc Fault
1.
4.
2.
5.
3.
6.
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Lifespan of an Arc Fault
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50 kA bolted fault between 480 Vac and ground
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Effects of an Arc Fault
Plenty of Hazards to Choose From
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Examples of Arc Faults
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Arc Flash Relay
 PGR-8800 Series
– 1ms reaction time
 Detects light
– Point sensors (A)
– Fiber optic sensor (B)
 Detect over-currents
– Phase CTs (3)
– Any CT with 5A sec.
 Link upto (4) AF Relays
– Larger systems
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PGR-8800
Functions & Features
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Six light sensors
Built-in front sensor
Adjustable light sensitivity
1000 event logging
Dual inputs for switches or
PLC
 Fail-safe operation
 Local USB interface
– No drivers or s/w req’d
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PGR-8800 Wiring Diagram
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PGA-LS10 - Point Sensors
The sensor can be also be mounted
to ”see through” the back of the cabinet.
Ø3.5 mm
8 mm
Sensor
Lens
52 mm
Red LED for
Circuit-check
& Visual Diagnostics
32 mm
Coverage
Half-Circle
120%
Range is 2 to 2.5 meters
10 m
100%
360°
360°
Mounting
Holes
(front / back)
100%80%
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Point Sensor
80%100%
PGA-LS20 - Fiber-Optic Sensors
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26 ft flexible fiber
360° detection angle
LED for visual feedback
Built-in circuit check
Electrically extendable
Plug-in connector
One fiber-optic sensor can replace several point sensors
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Multi-Unit Installation Example
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LINK
Switchboard
Supply
2
L1 L2 L3
Trip
Electrical cables
Sensors Detecting Arc
Fiber-Optic Sensor
Point Sensors
System can be expanded with up to four PGR-8800 Modules
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PGR-8800 Applications
Transformer secondary
3 x 22 kV
Transformer primary
3 x 690 V
Air-cooled transformers are sensitive to contaminants,
affecting the resistance of the air gap between electrical
connections (phases, bolted connections etc.)
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PGR-8800 Applications
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Additional Information
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www.startco.ca/arcflash
Datasheet
Product Manual
Brochure
Littelfuse Startco:
306-373-5505
Arc Flash Relay
Brochure PF136
Datasheet
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