© 2001 cooper bussmann, inc. presentado por: jesús a. baez m. itesm, departamento de ingeniería...

© 2001 Cooper Bussmann, Inc.

Presentado por: Jesús A. Baez M.

ITESM, Departamento de Ingeniería Eléctrica

Monterrey, NL Octubre 2007

Coordinación Selectiva de los elementos de protecciónReferencia: http://www.bussmann.com

•Definiciones•Coordinación con fusibles•Coordinación con interruptores•Ejemplo de coordinación en una planta industrial

Sistemas Eléctricos Industriales


Selective Coordination

Definition:

The act of isolating a faulted circuit from the remainder of the electrical system, thereby eliminating unnecessary power outages. The faulted circuit is isolated by the selective operation of only the overcurrent protective device closest to the overcurrent condition.

Without Selective Coordination With Selective Coordination

Selective Coordination: Avoids BlackoutsSelective Coordination: Avoids Blackouts

OPENS

NOT AFFECTED

UNNECESSARYPOWER LOSS

OPENS

NOT AFFECTEDFault Faul

t


Selective Coordination: NEC®

240.2 Definitions

Coordination.

The proper localization of a fault condition to restrict outages to the equipment affected, accomplished by the choice of selective fault-protective devices.


Selective Coordination: Normal Supply

ATS

EmergencySource

N E

NormalSource



Fault X1

ATS

EmergencySource

N E

NormalSource

OpensNot AffectedUnnecessaryPower Loss

Unnecessary Feeder Outage



Fault X1

ATS

EmergencySource

N E

NormalSource


Blackouts Possible!

Without

Unnecessary Main Outage



Fault X1

ATS

EmergencySource

N E

NormalSource

ATSN E


EmergencySourceNormal

Source

Blackouts Possible!

Without With


WithoutSelective Coordination: Normal Supply

Fault X1

ATS

EmergencySource

N E

NormalSource

ATSN E


With

Fault X1

EmergencySourceNormal

Source

Blackouts Prevented!

Blackouts Possible!

Isolated to Branch Only



Circuit Breaker Coordination


Coordination - Thermal-Mag Circuit BreakersCoordination - Thermal-Mag Circuit Breakers

Thermal Magnetic Molded Case Circuit Breaker Time-Current Curve Overload Region

Instantaneous RegionInterrupting TimeUnlatching Time

Interrupting RatingInterrupting Rating


Coordination - Thermal-Mag Circuit Breakers (See SPD)Coordination - Thermal-Mag Circuit Breakers (See SPD)

No se tiene selectividad para corrientes de corto circuito en este rango

400A

90A



Current

Tim

e

A

B

C

D

4000A Fault


OPENS

NOT AFFECTED

UNNECESSARYPOWER LOSS Fault

Lacking Coordination


Selective Coordination - Insulated Case Circuit Breakers (See SPD)Selective Coordination - Insulated Case Circuit Breakers (See SPD)

2000A Insulated Case Circuit Breaker STD Is an Option - Allows breaker to delay opening Instantaneous Override built-in: may be as low as 12X the breaker rating Will often result in lack of coordination


Selective Coordination - Insulated Case Circuit Breakers (See SPD)Selective Coordination - Insulated Case Circuit Breakers (See SPD)

2000A Insulated Case with STD and Instantaneous Override and 100A Molded Case Thermal Magnetic Circuit breaker - NO Coordination in Short-Circuit Region (above 21,000A)

2000A

100A


Selective Coordination - LV Air Power Circuit Breakers (See SPD)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


Selective Coordination: Fuses


Time Current Curves

Selective Coordination:Fuses (See SPD)


Selectivity Ratio

Guide Based on

Thermal Principle

Based on I2t Clear Clear

Not MeltNot Melt

I2t melting > I2t Clearing 1200 A 600 A

Selective Coordination:Fuses (See SPD)


Selective Coordination (See SPD )

Selectivity Ratio Table Assures Coordination!No Plotting required!

LOW-PEAK® : LOW-PEAK®

2:1 Line:Load Ratio

Lin

e S

ide

Fu

se

Load Side Fuse


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


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 ?


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- Fuses


Fault

NOT AFFECTED

OPENS



Fault 10000 Amps

Low PeakKRP-C 1000 SP

Low PeakLPJ 200 SP

Low PeakLPJ 20 SP

Are These Selectively Coordinated?


Fault 10000 Amps


Low PeakLPJ 200 SP

Low PeakLPJ 20 SP


OPENS

NOT AFFECTED

Fault 10000 Amps


Low PeakLPJ 200 SP

Low PeakLPJ 20 SP

Selectively Coordinated



Fault 10000 Amps

1000 A. CBIT @ 10 X

200 A. CBIT @ 10 X

20 A. CBIT @ 10X



Fault 10000 Amps

1000 A. CBIT @ 10 X

200 A. CBIT @ 10 X

20 A. CBIT @ 10X

Not Coordinated

OPENS

NOT AFFECTED

Fault 10000 Amps

1000 A. CBIT @ 10 X

200 A. CBIT @ 10 X

20 A. CBIT @ 10X


UnnecessaryBlackout

The Issue:Lack of coordinationtakes out other loads

OPENSFault 10000 Amps

1000 A. CBIT @ 10 X

200 A. CBIT @ 10 X

20 A. CBIT @ 10X


Ejemplo de coordinación mostrando protección de los cables

© 2001 cooper bussmann, inc. presentado por: jesús a. baez m. itesm, departamento de ingeniería...

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