Page 1
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 1/60
© 2001 Cooper Bussmann, Inc.
Suggestion on How to Use
• Industry Trainers are encouraged to use thismaterial in their sessions
• Download both the PowerPoint file (.ppt) and script
file (.pdf)• Print the script file (.pdf) and read the script as you
view the PowerPoint presentation in the “SlideShow” view. In this way you see the slides in largeformat and have animation (if there is any)
• Must have PowerPoint and Adobe Reader application software on your system.
Page 2
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 2/60
SelectiveCoordination
Page 3
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 3/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination
• For 600 Volts & less
• Easy concept to understand
• Hard to verify, if you do not know what to look for
• Misinterpretations or lack of understanding is veryprevalent
• People review curves (hand drawn or computer generated) and they do not know how to interpret
Page 4
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 4/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination
Definition:
The act of isolating a faulted circuit from theremainder of the electrical system, therebyeliminating unnecessary power outages. Thefaulted circuit is isolated by the selective operationof only the overcurrent protective device closest to
the overcurrent condition.
Page 5
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 5/60
Without Selective Coordination With Selective Coordination
Selective Coordination: AvoidsBlackouts
OPENS
NOT AFFECTED
UNNECESSARY
POWER LOSS
OPENS
NOT
AFFECTED Fault Fault
Page 6
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 6/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination: NEC®
240.2 Definitions
Coordination.
The proper localization of a fault condition torestrict outages to the equipment affected,accomplished by the choice of selective
fault-protective devices.
Page 7
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 7/60© 2001 Cooper Bussmann, Inc.
Selective Coordination: NEC ®
240.12 Electrical System Coordination whereorderly shutdown required to minimizehazards
620.62 Selective Coordination required wheremore than one elevator is supplied by singlefeeder.
517.17 Selective coordination between main
and feeder required for health care facilitieswhere main has GFP (feeder also required tohave GFP).
Page 8
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 8/60© 2001 Cooper Bussmann, Inc.
Selective Coordination
Chapter 2 VideoSelective Coordination
Page 9
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 9/60© 2001 Cooper Bussmann, Inc.
Selective Coordination
CoordinationCircuit Breakers
Page 10
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 10/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Bimetal
Magnetic Element
Line
Load
Trip BarCircuit Breaker
Operation
Page 11
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 11/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Bimetal
Line
Load
Trip Bar Thermal OverloadOperation
Normal State
Page 12
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 12/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Line
Load
Trip Bar
Bimetal
Thermal OverloadOperation
Unlatch & Open
Page 13
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 13/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Magnetic Element
Line
Load
Trip Bar Short CircuitOperation
Normal State
Page 14
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 14/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsUnlatch
Magnetic Element
Line
Load
Trip Bar Short CircuitOperation
Unlatching
Page 15
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 15/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Magnetic Element
Line
Load
Trip Bar Short CircuitOperation
Opening
Page 16
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 16/60© 2001 Cooper Bussmann, Inc.
Spring Loaded ContactsLatch
Magnetic Element
Line
Load
Trip Bar Short CircuitOperation
Cleared
Page 17
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 17/60© 2001 Cooper Bussmann, Inc.
Coordination -Thermal-Mag Circuit Breakers
Thermal Magnetic Molded
Case Circuit Breaker Time-
Current Curve
Overload Region
Instantaneous Region
Interrupting Time
Unlatching Time
Interrupting Rating
Page 18
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 18/60© 2001 Cooper Bussmann, Inc.
Coordination -Thermal-Mag Circuit Breakers (See SPD)
Page 19
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 19/60© 2001 Cooper Bussmann, Inc.
Selective Coordination
Current
T i m e
A
B
C
D
4000A Fault
Page 20
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 20/60© 2001 Cooper Bussmann, Inc.
OPENS
NOT AFFECTED
UNNECESSARY
POWER LOSS Fault
Lacking Coordination
S l ti C di ti
Page 21
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 21/60© 2001 Cooper Bussmann, Inc.
Selective Coordination -Insulated Case Circuit Breakers (SeeSPD)
2000A Insulated Case
Circuit Breaker
STD Is an Option - Allows breaker to delay opening
Instantaneous Override
built-in: may be as low as12X the breaker rating
Will often result in lack of
coordination
S l ti C di ti
Page 22
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 22/60© 2001 Cooper Bussmann, Inc.
Selective Coordination -Insulated Case Circuit Breakers (SeeSPD)
2000A Insulated Case with
STD and Instantaneous Override
and 100A Molded Case ThermalMagnetic Circuit breaker - NO
Coordination in Short-Circuit
Region (above 21,000A)
Page 23
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 23/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination -LV Air Power Circuit Breakers (See SPD)
Short Time Delay - Allows the fault
current to flow for up to 30 cycles.
Used to coordinate with downstream
Subjects equipment to high
mechanical and thermal stresses, often
violating 110.10
Arc Flash/ Blast Risks Much
Higher
High Cost, Larger Equipment
Page 24
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 24/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination: Fuses
Page 25
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 25/60
© 2001 Cooper Bussmann, Inc.
Page 26
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 26/60
S l ti C di ti F
Page 27
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 27/60
© 2001 Cooper Bussmann, Inc.
Time CurrentCurves
Selective Coordination:Fuses(See SPD)
S l ti C di ti F
Page 28
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 28/60
© 2001 Cooper Bussmann, Inc.
Selectivity Ratio
Guide Based on
Thermal Principle
Based on I
2
t Clear
Not Melt
I2t melting > I2t Clearing
1200 A 600 A
Selective Coordination:Fuses(See SPD)
Page 29
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 29/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination (SeeSPD )
Selectivity Ratio Table Assures Coordination!
No Plotting required!
LOW-PEAK ® : LOW-PEAK ®
2:1 Line:Load Ratio
L i n e
S i d e
F u s e
Load Side Fuse
S l ti C di ti
Page 30
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 30/60
© 2001 Cooper Bussmann, Inc.
Example:
Main: KRP-C 1200 SP
Feeder: LPS-RK 200 SP
Branch: LPS-RK-30 SP
MSB
1200 A
200 A
30 A
480V, 3 phase
MCC
GFP
Selective Coordination -Fuses
Page 31
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 31/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination - Fuses
Use Selectivity Table
Main KRP-C 1200 SP
Feeder LPS-RK 200 SP
Branch LPS-RK 30 SP
What happens: Branch Circuit Isca = 5000 A or
50,000A or 300,000A ?
Page 32
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 32/60
© 2001 Cooper Bussmann, Inc.
Lineside KRP-C 1200SP to Loadside LPS-RK 200SP
1200/200 = 6:1 Table only need 2:1
Selective Coordination
Lineside LPS-RK 200SP to Loadside LPS-RK 30SP
200/30= 6.67:1 Table only need 2:1
Selective Coordination
Selective Coordination- Fuses
Page 33
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 33/60
© 2001 Cooper Bussmann, Inc.
Fault
NOT
AFFECTED
OPENS
Selective Coordination
Page 34
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 34/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination
Simple Rules for Checking
• Circuit Breakers (instantaneous trip)
• Fuses
Page 35
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 35/60
Can you look at this
and assess whether
coordinated?
You do not even
need to draw curve!
Page 36
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 36/60
Simple Rule: (Amp rating) x (I.T. setting) =
Isca @ which CB will unlatch:
CB IT IT
Amp Set Amp Pickup
100 5X 500
200 5X 1,000
400 10X 4,000
1600 12X 19,000
See SPD
100 A
200 A
400 A
1600 A
Page 37
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 37/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination
• You already know the simple rule for fuses.
• Simply use amp rating ratios• Typically 2:1 for
Low Peak Fuses to Low Peak Fuses
Page 38
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 38/60
© 2001 Cooper Bussmann, Inc.
Selective Coordination
• Do coordination exercise using simple rules
– Fusible system – Circuit breaker system
• It’s simple!
Page 39
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 39/60
© 2001 Cooper Bussmann, Inc.
Fault
10000 Amps
Low Peak KRP-C 1000 SP
Low Peak
LPJ 200 SP
Low Peak
LPJ 20 SP
Are These Selectively
Coordinated?
Page 40
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 40/60
© 2001 Cooper Bussmann, Inc.
Fault
10000 Amps
Low Peak KRP-C 1000 SP
Low Peak
LPJ 200 SP
Low Peak
LPJ 20 SP
Are These Selectively
Coordinated?
OPENS
NOT
AFFECTED
Fault
10000 Amps
Low Peak
KRP-C 1000 SP
Low Peak
LPJ 200 SP
Low Peak
LPJ 20 SP
Selectively Coordinated
Page 41
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 41/60
© 2001 Cooper Bussmann, Inc.
Are These Selectively
Coordinated?
Fault
10000 Amps
1000 A. CB
IT @ 10 X
200 A. CB
IT @ 10 X
20 A. CB
IT @ 10X
Page 42
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 42/60
© 2001 Cooper Bussmann, Inc.
Are These Selectively
Coordinated?
Fault
10000 Amps
1000 A. CBIT @ 10 X
200 A. CB
IT @ 10 X
20 A. CB
IT @ 10X
Not Coordinated
OPENS
NOT
AFFECTED
Fault
10000 Amps
1000 A. CB
IT @ 10 X
200 A. CB
IT @ 10 X
20 A. CB
IT @ 10X
Page 43
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 43/60
© 2001 Cooper Bussmann, Inc.
Unnecessary
Blackout
The Issue:
Lack of coordination
takes out other loads
OPENS Fault
10000 Amps
1000 A. CB
IT @ 10 X
200 A. CB
IT @ 10 X
20 A. CB
IT @ 10X
Ground Fault Protection 230 95
Page 44
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 44/60
© 2001 Cooper Bussmann, Inc.
Ground Fault Protection 230-95
Page 45
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 45/60
© 2001 Cooper Bussmann, Inc.
See SPD
GFP H lth C 517 17
Page 46
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 46/60
© 2001 Cooper Bussmann, Inc.
GFP Health Care 517-17
Where one level of GFP is provided per 230.95 or 215.10 anadditional step of GFP on feeders required.
The Ground Fault Protection for service and feeder shallbe fully Selectively Coordinated
What does this mean ?
Page 47
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 47/60
© 2001 Cooper Bussmann, Inc.
517-17 Health Care GFP
Main 1200 A CB
Feeder 200 A CB
GFP on Main & Feeder
Does this meet 517-17?
Page 48
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 48/60
© 2001 Cooper Bussmann, Inc.
517-17 Health Care GFP
Main 1200 A Fuse
Feeder 200 A Fuse
GFP on Main & Feeder
Does this meet 517-17?
Page 49
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 49/60
© 2001 Cooper Bussmann, Inc.
Following Excerpts from IEEE Standards
IEEE 242 1986 “BUFF BOOK”
Page 50
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 50/60
© 2001 Cooper Bussmann, Inc.
IEEE 242-1986 BUFF BOOK Protection and Coordination of Industrialand Commercial Power Systems
Page 263 6.4.1 Protection (SeriesConnection). It should be noted thatselectivity will not be provided at any currentlevel where the breaker trip characteristiccurves overlap when this protection scheme isused, that is, both circuit breakers will trip.
IEEE 242-1986 “BUFF BOOK”
Page 51
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 51/60
© 2001 Cooper Bussmann, Inc.
IEEE 242-1986 BUFF BOOK Protection and Coordination of Industrialand Commercial Power Systems
Page 528 Coordination 14.2.2
Coordination can easily be achieved with low
voltage current-limiting fuses that have fastresponse times. Manufacturer’s time currentcurves and selectivity ratio guides are used for both overload and short-circuit conditions,
precluding the need for calculating time intervals.
IEEE 141 1993 “RED BOOK” Electrical
Page 52
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 52/60
© 2001 Cooper Bussmann, Inc.
IEEE 141-1993 “RED BOOK” Electrical
Power Distribution for Industrial Plants
Page 256 5.7.2.3 Low-voltage circuitbreakers. To achieve this level of selectivity,power circuit breakers utilize short-time delaytrips. The equipment protected by thisbreaker must be designed to handle theavailable short-circuit current for the durationof the short-time delay.
IEEE 242 1986 “BUFF BOOK”
Page 53
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 53/60
© 2001 Cooper Bussmann, Inc.
IEEE 242-1986 “BUFF BOOK” Protection and Coordination of Industrialand Commercial Power Systems
Page 528 Coordination 14.1 A coordination
study should be made when the availableshort-circuit current of the source to the plantis increased.
IEEE 242 1986 “BUFF BOOK”
Page 54
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 54/60
© 2001 Cooper Bussmann, Inc.
IEEE 242-1986 “BUFF BOOK” Protection and Coordination of Industrialand Commercial Power Systems
Page 528 Coordination 14.1 A coordination study
or revision of a previous study may be needed for an existing plant when new loads are added to thesystem or when existing equipment is replacedwith higher rated equipment.
IEEE 602 1996 “WHITE BOOK”
Page 55
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 55/60
© 2001 Cooper Bussmann, Inc.
IEEE 602-1996 WHITE BOOK” Electrical Systems in Health CareFacilities
Page 57/58 3.7.1.1 Protection requirements. As total selectivity and maximum safety topersonnel are critical, a total short-circuitcoordination, and component protection studyshall be performed.
IEEE 141 1993 “RED BOOK” Electrical
Page 56
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 56/60
© 2001 Cooper Bussmann, Inc.
IEEE 141-1993 RED BOOK Electrical
Power Distribution for Industrial Plants
Page 256 5.7.2.3 Low-voltage circuitbreakers. It should be recognized thatproviding selectivity to the load-side devices
may result in equipment bus structures beingunderprotected. The Standards for suchequipment, ANSI/UL 891-1984 [B21] for switchboards, ANSI/UL 845-1987 [B20] for motor control centers,
IEEE 1015-1997 “BLUE BOOK”
Page 57
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 57/60
© 2001 Cooper Bussmann, Inc.
IEEE 1015-1997 BLUE BOOK
Applying Low-Voltage Circuit BreakersUsed in Industrial and Commercial Power
Systems
Page 135 5.5.4 Short-time delay
All MCCBs and most ICCBs with a short time delayhave an instantaneous override. If selectivecoordination is required for fault currents above theinstantaneous override level, a power circuit
breaker defined as an LVPCB with a short-timedelay option, as shown in Figure 5-16, should beconsidered.
IEEE 242-1986 “BUFF BOOK”
Page 58
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 58/60
© 2001 Cooper Bussmann, Inc.
IEEE 242 1986 BUFF BOOK Protection and Coordination of Industrialand Commercial Power Systems
Page 252 6.3 Trip Unit The resulting combination of long-time delay and short-time delay characteristicsprovides delayed tripping for all levels of overcurrent
below the instantaneous response. This providestime for downstream circuit breakers to operate andclear the fault. The withstand of other electricalcomponents in the current path should be checked
to be certain they can handle the additional stressassociated with the longer clearing time.
IEEE 1015 1997 “BLUE BOOK”
Page 59
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 59/60
© 2001 Cooper Bussmann, Inc.
IEEE 1015-1997 BLUE BOOK
Applying Low-Voltage Circuit BreakersUsed in Industrial and Commercial Power Systems
Page 62 3.38 Series-connected rating.Sometimes it is erroneously thought that series
combinations are at a disadvantage with regard tocoordination as compared to fully rated systems.The fact is that even fully rated circuit breakerswith instantaneous trips will not “coordinate” once
the fault level exceeds both circuit breakers’instantaneous trip levels.
IEEE 1015-1997 “BLUE BOOK”
Page 60
7/28/2019 21955721 Selective Coordination
http://slidepdf.com/reader/full/21955721-selective-coordination 60/60
IEEE 1015-1997 BLUE BOOK
Applying Low-Voltage Circuit BreakersUsed in Industrial and Commercial Power Systems
Page 134 5.5.3 Series MCCBs
Selective coordination is limited to currents
below the instantaneous pickup of the line-side circuit breaker. For any fault downstreamof the load-side MCCB having a currentgreater than the instantaneous pickup of the
line-side MCCB, both circuit breakers trip, andpower is interrupted to unfaulted circuits fed bythe line-side circuit breaker.