1. Interfacing IEC 61850 Station Bus Protection to Existing Protection in a Brown-field Substation
Georgia Tech Protective Relaying Conference
May 2, 2018
Donald Pratt and Mark Seiter
Consolidated Edison Company of New York, Inc.

2. Agenda Observations and recommendations Example migration process
Green-field (new) vs brown-field (existing)
Understanding migration
Outage sequence and configuration files
Migration independent of outage sequence
Example migration process
Project description
Cataloging existing system
Recognizing functional elements and fitting them to the data model
Data acquisition and devices with common configurations
Conclusions

3. Green-field vs brown-field
new
new
new
old
old
old
old
new
old
old
new
new B1 B2 B3 31 12 23
Brown-field (complicated by interface between “new” and “old”)
Outage sequence B1 then B2 then B3
Outage 1: new, old, old
Outage 2: new, new, old
Outage 3: new, new, new

4. Understanding migration
System Operations
SCADA migration
Points are tied to the primary equipment outage
RTU
I/O
RTU
I/O
Commissioned
Outage 1
Commissioned
Outage 2
Retired
Outage 1
Retired
Outage 2

5. Understanding migration
System Operations
Protection migration
Points are tied to what is adjacent to the primary outage
RTU
I/O
Data
Concentrator
IED
Interface
Interface
Retired
Outage 1
Retired
Outage 3
Retired
Outage 2

6. Outage sequence and configuration files
Example of “new-new” with a bus fault
Representation of GOOSE communication
Publisher
TRIP X
Message
Subscriber
BF INIT
Circuit Breaker Interface
BF TRIP

7. Outage sequence and configuration files
Example of “new-old” with a bus fault
TRIP
Configuration change required
Line Diff. Relay & CBI
Must now subscribe to Interface X
LOCKOUT OPERATION
BF INIT
TRIP
BF TRIP

8. Migration independent of outage sequence
Outage sequence may change
29 major outages over 5 year project installation schedule
Create flexibility by over-designing the publisher-subscriber relationships
Consider each section to be the first commissioned
Identify all publisher-subscriber relationships to interface “new-old”
Consider each section in the final configuration
Identify all publisher-subscriber relationships for “new-new”
This covers all possible combinations
All sequence possibilities may be verified during acceptance testing

9. Migration independent of outage sequence
Buying greater flexibility
Field engineers may adjust to outage sequence changes without modifying configurations
Reduced engineering during time-constrained outage windows
Not without cost
Paying for it with added complexity
Not all publisher-subscriber relationships will be used
Only one of any two busses can be commissioned first
Communication alarms will need to be suppressed
When publishers stop publishing, subscribers alarm

10. Project description 345 kV
8 feeders. 8 autotransformers, 4 GIS breaker assemblies
138 kV
7 feeders, 12 bus sections, 33 breakers
21 pressurization and cooling plants

11. Project description Typical arrangement “old-new” interface
New GIS breaker
Typical arrangement
Outage Sequence
One pair of feeders at a time
A full outage season
29 outages
5 year schedule
“old-new” interface
On the 138kV bus sections
Interface not obvious
B (Bus)
F (Feeder)
T (Transformer)

12. Cataloging existing system
Capture each point in a spreadsheet
Data is used to inform interface device decisions
Identify outage when points are commissioned and retired B
Bus data T
T Breaker Data

13. Recognizing functional elements and fitting them to the data model
The migration plan is an effort to surrogate the devices that the new data model is expecting, but are not currently installed

14. Data acquisition and devices with common configurations
Bus1
Data
Bus2
Data
Parsimonious vs lavish design
Bus section “data” is similar bus to bus
Bus, Feeder, and Transformer data
Lockout count
Parsimonious
Design only for the bus its on
Lavish (one size fits all)
Design for “max case” of each data type
Only wire what is needed
Configuration is common
GOOSE data set is uniform B F T B T F
Bus3
Data B T
Interface Device Requirement T F B

15. Conclusion Observations and recommendations IEC 61850 and migration
Protection migration should be included in the project specification
Bid evaluations should heavily weight the migration plan
Migration plan should be designed to require no configuration modifications for changes in outage sequence
IEC and migration
The project specification should include a catalog of the existing system
The migration process should use the existing system to fill in the missing portions of the new systems data model
Common configurations should be developed to support a uniform data model