Using IED Data To ImplementSubstation Automation Functions
Reducing Costs by Reusing Available Data
Gerrit DoggerProduct and Application Specialist
Cybectec Inc.
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Objectives
Where are we and what is neededThe benefits of using IED dataDiscussion of challenges and their solutionsDiscussion of future developmentsReal-world case study: Emergency power management and load restoration
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Substation Evolution1/2Existing situation
SCADA
RTU
IED
PROTECTION METERING POWERQUALITY
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Substation Evolution2/2New situation:
IEDs for protection, measurement and controlSubstation gateway/data concentrator for communication
IED
PROTECTION METERING POWERQUALITY
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Automation Requirements
Substation automation functions need –Access to all substation dataControl capability of substation switchgearA device with programming capability
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Introducing the Intelligent GatewayA communications gateway provides data access and control capabilitiesAn intelligent gateway also provides automation capabilities
Replaced by
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Direct Benefits of the Intelligent Gateway
No PLC or other additional devices neededFewer devices reduce administrative costsNo additional cabling – IEDs are already connectedOpportunity for optimized price/performance relay configuration
Reinforced by the additional intelligenceSimplified substation architecture – vendor independent
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Indirect Benefits of the Intelligent GatewayThese might be more important in the long run –
Simpler diagrams because of reduced cablingLess maintenance on diagramsFewer devices means
Fewer spare partsLess training
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Challenges and Their Solutions
Using intelligent gateways introduces new challenges –Response timesException handlingSupporting redundancy
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Response Times – Issues
Data acquisition delays due to communication between gateway and IEDDelay in command execution
Note: Immediate faults are handled by the IED.
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Response Times – Solutions
Modern protocols reduce data acquisition delays –DNP3, IEC 60870-5-101, IEC 60870-5-104 use unsolicited reporting
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Response Times – Solutions
Processor/task priority reduce the command delay –High priority for
Automation tasksCommand handlingIED command handling
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Exception Handling – Issues
Special care needs to be taken for –Invalid incoming dataCommand execution error handling
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Exception Handling – Solutions
Data invalidity can be handled by –Checking individual data point quality Checking the communication link status
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Exception Handling – Solutions
For command execution –Check the protocol command acknowledgementCheck the corresponding indications
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Supporting Redundancy – Issues
Redundancy introduces additional challenges –Correct handling of failover situationsSynchronization of data between the programsNo or limited concurrent execution
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Supporting Redundancy – Solutions
To ensure correct execution –Plan redundancy from the startUse internal program indicationsUse external indications – binary inputs
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Supporting Redundancy – Solutions
Fast failover needs data synchronizationGateway must address this issue
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Supporting Redundancy – Solutions
Both synchronized gateways might execute the program.Highly undesirable Should be solved in the design
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Future Developments
Some trends we see developing:IEC 61850 – GOOSE messages can optimize interaction
Communication availability Substations can share more dataThis enables region-wide automation
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Real-World Case Study: Emergency Power Management and Load Restoration
EDG #3 EDG #2 EDG #1
Incomer #1 Incomer #2
52L-3
52L-2 52L-1 52R-1
52R-2
52L-RNO
F17F16F1 F2
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REDUNDANT CONTROLCENTERS
REDUNDANT GATEWAYS
EDG MCP
INCOMERUNDERVOLTAGE
PLCS
FEEDER IEDSGENERATORBREAKER IEDS
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Start state
Wait for feeders toopen
IDLE
C: Start of SMPA: Initialize system
C: NOT `Permissive to syn and close EDG`s CBs`
A: Open feeders
Wait for powerfrom generators
C: (Both incomers open &
A: Set `Permissive to syn and close EDG`s CBs
C: All feeders open &C: Bus load less than 1 MW) OR
Closing feeders
C: 1 or more EDG`s CB s closedA: Calculate power
C: Power is availableA: Calculate power
C: One or both incomers closed
Wait for closeconfirmation
C: (Feeder is closed || timeout (5sec)) &
A: Determine next feederC: Not all feeder are closed
A: Determine next feeder
A: Close selected feeder
C: Both incomers open &
C: `Permissive to syn and close EDG`s CBs`C: Both incomers open &
C: `Permissive to syn and close EDG`s CBs`C: One or both incomers closed &
A: Reset `Permissive to syn and close EDG`s CBs
C: FeederOpenTimer timout (10 sec)
C: One or both incomers closed
C: One or both incomers closed
Determine CloseFail
C: All feeders Done &
A: Retrycounter := Retrycounter + 1C: Retrycounter < 3
C: Feeders to retry deteminatedA: Determine next feeder
C: One or both incomers closed
Initialization andIDLE state
Blackout: open feeders
Feeders open:Start generators
Power:Close feeders
(priority based)
Retry feeders that didn’t close
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Emergency Power Management and Load Restoration
Basic factsPut into service in November 2005Normal conditions: restore power within 1 minute
Mainly waiting for generators to come onlineFailover condition: restore power within 1.5 minutes
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Concluding Remarks
BenefitsNo additional hardwareUses existing data and wiringFewer spare partsLower administration costs –
Minimal training neededEverything is available to implement it nowProven concept
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Concluding Remarks
DevelopmentBetter interaction using IEC 61850 GOOSE messagesUpcoming opportunities for region-wide automation
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Questions?