Frankfurt (Germany), 6-9 June 2011
RT3b – André Smit, Siemens USA
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U.S. Distribution Feeder Automation Pilot Project
We have developed a peer-to-peer feeder
automation system using WiMAX and IEC61850
During the project we needed to develop new
protection settings for the feeder
We found that conventional settings of
coordinated overcurrent relays was not possible
The relay setting groups could not be adapted to
all the different operating scenarios we faced
We needed to find a solution that was less
complicated with better performance
Frankfurt (Germany), 6-9 June 2011
Traditional Feeder Operation
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Overcurrent protection operate and trip
Utility receives a fault notification from a
customer experiencing an outage
Trouble desk dispatches a line crew to locate
and isolate the fault
Crew restores service to unaffected sections of
line
Crew effects repairs and restores feeder to
normal operation
Outage time could be measured in hours
André Smit – U.S. – RT3b
Frankfurt (Germany), 6-9 June 2011
Automation of the Distribution Feeder
FLISR
 Fault Location, Isolation, and Service
Restoration
Circuit Breaker
Recloser
Switch
Frankfurt (Germany), 6-9 June 2011
Feeder Automation Pilot Project
Frankfurt (Germany), 6-9 June 2011
Automating the Distribution Feeder
Operational Features to Consider
 Change open point based on loading
 Isolate line sections for maintenance
 Transfer to healthy source
Circuit Breaker
Recloser
Frankfurt (Germany), 6-9 June 2011
Different curve shapes to deal with
Relay protecting power
transformer does not have
same shape curve as fuse
designed to protect small
distribution feeder load
Frankfurt (Germany), 6-9 June 2011
Affect when lowering the Isc
The effect of moving 50
setting to indicate what
happens when Isc is low.
Little room to coordinate
with 51 element. Cannot
coordinate with 50 element
as a higher Isc will cross
both lines and both relays
will trip.
Frankfurt (Germany), 6-9 June 2011
Affect without low Isc being a factor
If low Isc not a factor, more
space to coordinate with 51
element and still stay above
fuse.
Frankfurt (Germany), 6-9 June 2011
3 Reclosers with Tolerance Affect
Typical TCC curve showing
high and low tolerances.
(Used ±5% on pickup & time.)
Not considering CT tolerance.
Illustrates need for space
between curves.
Frankfurt (Germany), 6-9 June 2011
1 Recloser
Only one recloser easy to fit
between max fuse and
feeder main breaker.
Better coordination (more
space) between all four
devices.
Frankfurt (Germany), 6-9 June 2011
One set of TCC curves of 16 sets
Using four total setting groups
ComponentName P1 50/51
Manufacturer SIEMENS
7SJ62/63/64, TOC ANSI
7SJ64X
CT Ratio 600 / 5 A
Settings Phase
51 (0.5-20.0 x CTR) 3 (360A)
ANSI Extremely Inv. 2.58
50-1 (0.5-175 x CTR) 7.92 (950.4A)
50-1 Delay (0-60 Sec) 0.1
Match curves
to data
by color
ComponentName P2 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.39 (312A)
ANSI Extremely Inv. 0.48
50-1 (0.05-50.0 x CTR) 1.15 (920A)
50-1 Delay (0-60 Sec) 0.15
150 A
360 A
312 A
256 A
200 A
51 pickup markers
Largest downstream fuse
Feeder main breaker and
three reclosers
KEL 69KV T1B-OC
ComponentName P3 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.32 (256A)
ANSI Extremely Inv. 0.45
50-1 (0.05-50.0 x CTR) 0.78 (624A)
50-1 Delay (0-60 Sec) 0.15
Upstream Transformer
or Bus Main Breaker
ComponentName P4 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.25 (200A)
ANSI Extremely Inv. 0.48
50-1 (0.05-50.0 x CTR) 0.5 (400A)
50-1 Delay (0-60 Sec) 0.15
50 active only during reclose
MAX FU 1-2
890 A
1308 A
1357 A
1386 A
2189 A
2189 A
TCC Name: BKR KEL 69KV THRU TO OPEN P5
Current Scale x 1 Reference Voltage: 25000
March 31, 2011 9:54 PM
Siemens Energy Automation, Wendell, NC
Existing devices shown for reference. Instantaneous enabled only during reclose cycle.
P1 50-1 delay is 0.10 sec due to longer opening time for breaker vs. recloser.
Frankfurt (Germany), 6-9 June 2011
One set of TCC curves of 16 sets
Using four total setting groups
ComponentName P1 50/51
Manufacturer SIEMENS
7SJ62/63/64, TOC ANSI
7SJ64X
CT Ratio 600 / 5 A
Settings Phase
51 (0.5-20.0 x CTR) 3 (360A)
ANSI Extremely Inv. 2.58
50-1 (0.5-175 x CTR) 7.92 (950.4A)
50-1 Delay (0-60 Sec) 0.1
Match curves
to data
by color
ComponentName P2 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.39 (312A)
ANSI Extremely Inv. 0.48
50-1 (0.05-50.0 x CTR) 1.15 (920A)
50-1 Delay (0-60 Sec) 0.15
150 A
360 A
312 A
256 A
200 A
51 pickup markers
Largest downstream fuse
Feeder main breaker and
three reclosers
KEL 69KV T1B-OC
ComponentName P3 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.32 (256A)
ANSI Extremely Inv. 0.45
50-1 (0.05-50.0 x CTR) 0.78 (624A)
50-1 Delay (0-60 Sec) 0.15
Upstream Transformer
or Bus Main Breaker
ComponentName P4 50/51
Manufacturer SIEMENS
7SR224, TOC ANSI
7SR224
CT Ratio 800 / 1 A
Settings Phase
51 (0.05-2.5 x CTR) 0.25 (200A)
ANSI Extremely Inv. 0.48
50-1 (0.05-50.0 x CTR) 0.5 (400A)
50-1 Delay (0-60 Sec) 0.15
50 active only during reclose
MAX FU 1-2
890 A
1308 A
1357 A
1386 A
2189 A
2189 A
TCC Name: BKR KEL 69KV THRU TO OPEN P5
Current Scale x 1 Reference Voltage: 25000
March 31, 2011 9:54 PM
Siemens Energy Automation, Wendell, NC
Existing devices shown for reference. Instantaneous enabled only during reclose cycle.
P1 50-1 delay is 0.10 sec due to longer opening time for breaker vs. recloser.
Frankfurt (Germany), 6-9 June 2011
Difficulties in Coordinating Feeder
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Reclosers are in series on feeder and not located
on branches
Segments have different types of loads
Curves for transformers are not as steep
Demand changes by time of day and season and
differently for each segment
Melt/time characteristics for distribution fuses
do not fit closely with substation transformer
protection upstream
Original system designed without new switching
points
Frankfurt (Germany), 6-9 June 2011
Difficulties in Coordinating Feeder
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High source impedance + long line = very low fault
currents
Substations located at the ends of the line, so source
impedance is usually high; a long feeder—the best
candidate for automation—adds to the impedance
Severe limits caused by existing minimum current settings
and low short circuit current (Isc)
Low available Isc limits use of 50, or 50 with definite time
Must include considerable allowance for high-impedance
branch line faults causing Isc to be even lower
Inrush current could be five times nominal current,
therefore precluding the use of 50 element when Isc is
low
Frankfurt (Germany), 6-9 June 2011
How do we deal with these
difficulties to protect an
Automated Feeder?
Setting Sheets
Frankfurt (Germany), 6-9 June 2011
Our Solution
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Detect and isolate faults with a differential (87L) function
Activate a 50/51 overcurrent curve on one device end and
reclose on fault
Diff Zone
Diff Zone
Primary
Switch 1
Primary
Switch 2
Primary
Switch 3
87
87
87
87
87
87
Relay 1
Relay 2
Relay 3
Frankfurt (Germany), 6-9 June 2011
Performance
Direct Fiber
WiMAX
30 msec
80 msec
Frankfurt (Germany), 6-9 June 2011
Automating the Distribution Feeder
Locate using 87L
Isolate using 87L & Restore
Reclose using 50/51
Restore
Frankfurt (Germany), 6-9 June 2011
New Protection for Automated Feeders
Fast
Selective
Uncomplicated
Minimal Disruption
for customers
Reclosers
Feeder Breaker
Transformer
Frankfurt (Germany), 6-9 June 2011
Questions