Download - RT3b – André Smit, Siemens USA

Frankfurt (Germany), 6-9 June 2011

RT3b – André Smit, Siemens USA

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


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

Traditional Feeder Operation


Automation of the Distribution Feeder

FLISR Fault Location, Isolation, and Service

Restoration

Circuit Breaker Recloser Switch


Feeder Automation Pilot Project


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


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


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 elementas a higher Isc will cross both lines and both relays will trip.


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.


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.


1 Recloser

Only one recloser easy to fit between max fuse and feeder main breaker.Better coordination (more space) between all four devices.


One set of TCC curves of 16 setsUsing four total setting groups

150 A

2189 A

360 A

2189 A

312 A

1357 A

256 A

1308 A

200 A

890 A

1386 A

KEL 69KV T1B-OC

ComponentName P1 50/51 Manufacturer SIEMENS7SJ62/63/64, TOC ANSI 7SJ64X CT Ratio 600 / 5 ASettings 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

ComponentName P2 50/51 Manufacturer SIEMENS7SR224, TOC ANSI 7SR224 CT Ratio 800 / 1 ASettings 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



MAX FU 1-2

KEL 69KV T1B-OC

ComponentName P1 50/51 Manufacturer SIEMENS7SJ62/63/64, TOC ANSI 7SJ64X CT Ratio 600 / 5 ASettings 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




MAX FU 1-2

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, NCExisting 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.

51 pickup markersLargest downstream fuseFeeder main breaker and three reclosers

50 active only during reclose

Match curvesto data

by color

Upstream Transformer or Bus Main Breaker


Difficulties in Coordinating Feeder 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


Difficulties in Coordinating Feeder 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


How do we deal with these difficulties to protect an Automated Feeder?

Setting Sheets


Our Solution Detect and isolate faults with a differential (87L) function Activate a 50/51 overcurrent curve on one device end and

reclose on fault

87

87

Relay 1

87

87

Relay 2

87

87

Relay 3

Diff Zone Diff Zone

PrimarySwitch 1

PrimarySwitch 2

PrimarySwitch 3


PerformanceDirect Fiber WiMAX

30 msec 80 msec


Automating the Distribution Feeder Locate using 87L

Isolate using 87L & Restore

Reclose using 50/51

Restore


New Protection for Automated Feeders

Transformer

Feeder Breaker

ReclosersFastSelectiveUncomplicated Minimal Disruption for customers


Questions