1 2007 APPA Engineering and Operations Technical Conference Atlanta, Georgia April 13-18, 2007 “Nailing the Basics” Earns Princeton, IL RP3 Diamond Award

11

2007 APPA Engineering and Operations Technical Conference

Atlanta, GeorgiaApril 13-18, 2007

“Nailing the Basics” Earns Princeton, IL RP3 Diamond Award

Jason Bird – City of Princeton, ILRon Till – S&C Electric Company

April 16, 2007

22

BackgroundBackground

33


County Seat of Bureau County Illinois

Area about 7.0 mi2

Population about 7,500 (2000)

City Owned Electric and Telecom Utilities

19 Electrical and Power Plant Employees

44


Approximately 4,300 Customers

12 distribution circuits

70% overhead line

30% underground

55


Receives bulk power at 138 kV

2 major substations:

138 kV => 34.5 kV and 12.47 kV

34.5 kV => 12.47 kV and 2.4 kV

Eight (8) multi-fuel engine-generators sets

• Used for summer peak shaving or export

66

77

The ChallengeThe Challenge

Major substation upgrade planned, but City didn’t have proper information to specify equipment or implement protection settings Short-circuit study required

Coordination study required

88

The ChallengeThe Challenge

Nearly 80% of the time transformer primary fuse, line fuse, and feeder breaker would operate

No reclosing relay on feeder breakers meant extended outages to Customers for transient faults

Need to improve reliability to Customers

99

The Solution The Solution

S&C engineers spent 2 days in the field collecting data for the studies.

• Nameplate information

• Line conductor sizes, configurations and lengths

• Verified existing system maps

• Review existing transformer and line fusing practices

1010

The Solution The Solution

An accurate model of the City’s distribution system was constructed

• Ran short-circuit studies in compliance with ANSI C37 standards to evaluate fault currents with and without generation

• Conducted coordination studies with and without influence of generation

1111

Study ResultsStudy Results

Indicated that the overcurrent protective devices were applied within their ratings with 38 MW of local generation off-line, but…...

Fault currents on the 12.47 kV system exceeded 18 kA (sym.) when on-line

Existing OCB’s in station and distribution class cutouts potentially over-dutied

1212


New breakers in substation would cover the interrupting ratings while generation was on-line….but devices beyond substation would not

Coordination study confirmed that high available fault currents made coordination with existing devices difficult

1313

Proposed ChangesProposed Changes

Evaluate ratings of distribution class cutouts City was already using Positrol® Fuse Links, so for

purposes of establishing interrupting ratings, assumed Type XS Open Cutouts had been applied universally on system

Largest fuse link in inventory was 100 Amperes, so two styles of cutouts to choose from:

1414


Type XS Fuse Cutout

Extra-Heavy-Duty Style 100 A Max. 14.4/15.0 kV Nom./Max. 110 kV BIL 12.0 kA, Asym.* 8.6 kA, Sym.** one-shot rating, based upon replacement of cutout tube

1515


Type XS Fuse Cutout

Ultra-Heavy-Duty Style 100 A Max. 14.4/15.0 kV Nom./Max. 110 kV BIL 16.0 kA, Asym. 10.6 kA, Sym.

1616


With generators off-line, Extra-Heavy-Duty Style cutouts were capable of interrupting fault currents on any feeder when they were placed a minimum of 1,000 circuit-feet away from the substation

Considered fault duty and X/R ratio

• ANSI C37.42-1996

– EHD tested at X/R = 8

– UHD tested at X/R = 12

1717


However, when the generators are on-line, the available fault currents are too high….need to go with Ultra-Heavy-Duty Style cutouts or even Power Fuses close to or in the substation

1818


SMD®-20 Power Fuse

Overhead-Pole Top Style 200 A Max. 17.0 kV Max. 110-150 kV BIL 22.4 kA, Asym. 14.0 kA, Sym.

1919


SMD®-40 Power Fuse

Station-Vertical Style 400 A Max. 17.0 kV Max. 110 kV BIL 40.0 kA, Asym. 25.0 kA, Sym.

2020


Fault Tamer® Fuse Limiter 20 A Max. 15.0 kV Max. 110-125 kV BIL 12.0 kA, Sym. 15,700 Max. I2t

2121


Listed the minimum number of circuit-feet and geographic locations for the application of each type of device with the generators on-line

2222

BenefitsBenefits

Protective devices applied within ratings

Standardization of protective devices / switches

Reliability has gone up

Customer satisfaction has increased

More time to perform maintenance / inspections

2323


Start by standardizing transformer fusing One simple chart for line crews

Minimize stock on trucks

Then select line fusing criteria

2424

kVA Ratings

S&C StandardSpeed

(TCC No. 123-6)

S&C "K“Speed

(TCC No.165-6)

S&C "FaultTamer”

(TCC No.450-8)

Single-Phase Three-Phase FLAFuse Link(Amperes)

Fuse Link (Amperes)

Fuse Cartridge(Amperes)

3 9 0.42 1 6K 10

5 15 0.69 2 6K 10

10 30 1.39 3 6K 10

15 45 2.08 5 6K 10

25 75 3.47 7 8K 10

37.5 112.5 5.21 10 10K 10

50 150 6.94 15 12K 10

75 225 10.4 20 20K 20

100 300 13.9 25 25K 20

167 500 23.1 40 40K -

250 750 34.7 65 65K -

333 1000 46.3 80 80K -

* conn. Δ-Δ, Δ-Y, and Y-Y

2525

PLOTTING VOLTAGE:

BY:

DATE:

NO:

EXISTING SETTINGS

S&C Electric Company

Chicago, Illinois 60626

Power Systems Services

12.47 kV

0.01

0.1

1

10

100

1000

0.5 1 10 100 1000 10000

Current in Amperes: x 10 at 12.47 kV and x 3.625 at 34.4 kV.

Tim

e in

Se

con

ds

2-Fuse S&C POSITROL STDRating: 20 [A]12.47 [kV]

3-Fuse S&C POSITROL T SPEEDRating: 100T [A]12.47 [kV]

4-Relay WEST CO-8 NORTH FEEDER (GROUND)Tap:0.80 TD: 1.5Pick Up:64 A 12.47 kVInst:1600 A(primary) CT: 400:5

5-Relay WEST CO-8 NORTH FEEDER (PHASE)Tap:4.00 TD: 0.6Pick Up:320 A 12.47 kVInst:2400 A(primary) CT: 400:5

6-Relay WEST CO-8 CB 101 (GROUND)Tap:0.80 TD: 1.6Pick Up:320 A 12.47 kVInst:5600 A(primary) CT: 2000:5

7-Relay WEST CO-8 CB 101 (PHASE)Tap:3.00 TD: 0.9Pick Up:1200 A 12.47 kVInst:16000 A(primary) CT: 2000:5

300 kVAFLA=13.89 [A]

300 kVAINRUSH=166.68 [A]

1-TransformerZ=5.75 []P=300 [kVA]12.47 [kV]

18000 kVAFLA=1240.82 [A]

18000 kVAINRUSH=14889.80 [A]


12.47 kV

34.5 kV

300kVA

18MVA

12.47 kV

34.5 kV

300kVA

18MVA

Existing Existing SettingsSettings

2626

Alternate Alternate SettingsSettings

PLOTTING VOLTAGE:

BY:

DATE:

NO:

ALTERNATE SETTINGS

S&C Electric Company

Chicago, Illinois 60626

Power Systems Services

12.47 kV

0.01

0.1

1

10

100

1000

0.5 1 10 100 1000 10000

Current in Amperes: x 10 at 12.47 kV and x 3.625 at 34.4 kV.

Tim

e in

Se

con

ds

2-Fuse S&C POSITROL STDRating: 20 [A]12.47 [kV]

3-Fuse S&C POSITROL T SPEEDRating: 100T [A]12.47 [kV]

4-Relay WEST CO-8 NORTH FEEDER (GROUND)Tap:0.80 TD: 1.5Pick Up:64 A 12.47 kVInst:1600 A(primary) CT: 400:5

5-Relay WEST CO-8 NORTH FEEDER (PHASE)Tap:4.00 TD: 0.6Pick Up:320 A 12.47 kVInst:2400 A(primary) CT: 400:5

6-Relay WEST CO-8 CB 101 (GROUND)Tap:0.80 TD: 1.6Pick Up:320 A 12.47 kVInst:5600 A(primary) CT: 2000:5

7-Relay WEST CO-8 CB 101 (PHASE)Tap:3.00 TD: 0.9Pick Up:1200 A 12.47 kVInst:16000 A(primary) CT: 2000:5

18000 kVAFLA=1240.82 [A]

18000 kVAINRUSH=14889.80 [A]


300 kVAFLA=13.89 [A]

300 kVAINRUSH=166.68 [A]


2727

BenefitsBenefits

Significant reduction in outages

Smaller areas affected by outages when they do occur

Only 27% of time transformer fuse takes out line fuse

Better fusing schemes

Customer satisfaction has increased

Breaker lockouts have been significantly reduced

Documents

1 2007 APPA Engineering and Operations Technical Conference Atlanta, Georgia April 13-18, 2007 “Nailing the Basics” Earns Princeton, IL RP3 Diamond Award