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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Contact Information

Gerrit DoggerProduct and Application SpecialistCybectec Inc.Gerrit.Dogger@Cybectec.com

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Questions?