This document discusses arc flash protection solutions. It defines arc flash as a short circuit caused by ionized air between live parts or a live part and ground. An arc flash releases heat, pressure and sound as explosive molten metals and gases. The document proposes solutions like installing arc flash protection in switchgear to reduce the duration of arc faults, protecting people and equipment and reducing downtime. It discusses using optical sensors and relays integrated with protection functions to quickly detect and isolate arc faults.

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Confidential Property of Schneider Electric |
Offer Positioning
Arc Protection

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• Arc flash is a short circuit through ionized air between one live part and a
ground or between live parts as two phases.
• Arc flash energy is released as excessive heat, pressure and sound.
• As a result, vaporizer solids (as copper, aluminum...), blast of molten metals,
radiated heat and pressure wave are released.
• The arc flash can be simply described as an explosion.
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Confidential Property of Schneider Electric |
What is Arc Flash

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Confidential Property of Schneider Electric |
Safety Arc flash protection function
Your challenge
“I want to protect my people as well as substation and equipment from arc
flash. And, I want to reduce downtime resulting from arc flash.”
Our solution
Arc flash mitigation solution should be installed in MV and LV cubicles to
avoid the arc flash fault impact by reducing the Arc duration. That will protect
people and reduce the destruction impact.
The fast light detection combined with current measurement allows a high
speed control of protection breakers.
Your benefits
• Enhanced people safety in operation
• Drastically reduce downtime in case of arc from weeks to days or even
hours
• Divide by 10X the repair cost
• Allows continuity of service of other equipment
Arc flash sensors
22% of fires are caused by electrical failures
Average outage incident in mission critical facilities lasts 90 minutes

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Insulation breakthrough in switchgear
• Not likely but still possible in severe over voltage case
Component failure
• Cable terminal failures, CT’s and VT’s , Station transformers
• Contactors, circuit breakers, circuit breaker connectors..
Human errors
• Falling tools/parts (screws, nuts, etc..)
• Use of wrong tools or Misuse, Forgotten measurement wires or groundings
Bad contacts
• Bad contacts (temperature rise/overload), Insufficient tightening moment
• Vibration, Over voltage
Animals
• Small animals are often the root cause of arc flash
• Very hard to prevent
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Confidential Property of Schneider Electric |
Arc - Causes

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Active Arc Protection
Normal OC Relays
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Confidential Property of Schneider Electric |
Arc – O/C Relays v/s active Arc protection
50/51
50/51N
50/51,
50/51N
50/51
50/51N
50/51
50/51N
87
•Sampling 15-30 ms
• Contact closure 5 ms
• Time delay setting 30 - 350 ms
• Breaker operate time 40 - 80 ms
Total fault clearing time typically:
- Outgoing 15+5+30+50 = 100 ms
- Income 15+5+350+50 = 420 ms
50/51
50/51N
50/51
50/51N
50/51
50/51N
50/51,
50/51N
87
• Light information 1ms
• O/C comparison 1ms
• Initiate trip 5 ms
• Breaker operate time 40 - 80 ms
Total fault clearing time typically:
- Outgoing 1+1+5+50 = 57ms
- Income 1+1+5+50 = 57ms
Resistance Grounded Network
- Fault clearence in 57 ms

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Arc flash offer overview
※ = Scada interface
◎ = Master unit
＃ = Protective relay
Relay with arc interface
Standalone High end system
System
Standalone System High End Systems
Relay
V321 + VAM-IO
Optical Sensors
V121, V125 V221 + VAM I/O
Integrated
Easergy P3
Easergy P5

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Stand alone Arc Flash by optical detection for Cubicle
Fault Detection at ignition
- Optical point sensor (1-7ms)
- Optical loop sensor
+ Current Detection (2-10ms)
Cubicle protection in LV or MV
Fault Extinguish
Switching Methods:
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Confidential Property of Schneider Electric |
Arc Flash Mitigation value
proposal
Circuit Breaker
40-70ms

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Confidential Property of Schneider Electric
Optical sensors
• Point sensor (electrical type)
• Fixed in each protected compartment
• Simple installation
• Exact fault spot location
• Recommended for MV applications
• Fiber optic sensor (loop type)
• Routed through protected areas
• Cost effective solution
• Recommended for LV applications
Common for all EA Arc flash protection offers

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Sensor placement LV
Sensor placing in LV switchgear
•Bus duct
•Auxiliary transformer
•Circuit breaker
•Point- or fibre sensor

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Confidential Property of Schneider Electric |
Sensor placement MV
Sensor placement on MCSet cubicle
The point sensors are located to supervise the
cable compartment, the bus bar compartment
and the circuit breaker compartment

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Confidential Property of Schneider Electric |
• Connect light sensors
Stand Alone – Light Detection
case 1 : Basic solution
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Confidential Property of Schneider Electric |
• Connect to breakers trip control
 If Arc fault, Total shutdown
 Possible nuisance tripping due to parasite lights
TRIP
• Install Vamp 121

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Confidential Property of Schneider Electric |
• Connect Light sensors
Stand Alone – Light Detection
Case 2 : Simple Solution
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Confidential Property of Schneider Electric |
• Connect each V125 to dedicated breakers
 If Arc Fault, trip of Selected breakers
 Possible nuisance tripping due to parasite lights
• Install V 125
TRIP
TRIP TRIP
• Connect Master Trip OUT of V125 1 & 2 to Master Trip
IN of module V125 3
MT OUT
MT IN

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Relay integrated arc flash protection enables
the following:
• Connect up to six (depending on model) arc flash
sensors directly to the P53 relay or P3x
• To receive light or current information from
another relay in the system through GOOSE or
Binary I/O
• To send light or current information to another
relay in the system trough GOOSE
• Selectivity schemes possible
• Typical use: new and retrofit solutions
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Confidential Property of Schneider Electric |
Arc protection philosophies
Integrated into relay protection
Relay
Goose
Goose

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Confidential Property of Schneider Electric
Feeder CB
Cable End
Busbar
S1
S2
S4
S1
S2
S4
S1
S2
S4
T2
S1
S2
S4
S1
S2
S4
S4
S3
S1
T2
T1
S1
S2
S4
S1
S2
About selectivity... What it is?

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TRIP
MT IN
System Arc Flash by optical detection for complete installation
TRIP TRIP
MT OUT
TRIP
TRIP
TRIP
MT OUT
MT IN
Fault Detection at ignition
- Optical point sensor (1-7ms)
- Optical loop sensor
+ Current Detection (2-10ms)
Circuit Isolation
- Relay Synchronization
- Logical Selectivity
- Time Selectivity
Fault Extinguish
- Circuit breaker Control (40-70ms)
- Fast switch control (20-50ms)
- Quenching device control (2-5ms)
Substation protection
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Confidential Property of Schneider Electric |
Arc Flash Mitigation value
proposal

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