Reducing Conventional Copper Signaling in High Voltage Substations with IEC 61850 Process Bus System David McGinn, GE Digital EnergyMaciej Goraj, GE Digital EnergyJorge Cardenas, GE Digital Energy

Digital EnergyMultilin

•International Scientific & Technical Conference

•“Actual Trends in Developments of Power System Protection and Automation”, 7-10 September 2009, Moscow

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• Robust and practical process bus architecture is a missing element on the road to implementing the next generation of Protection and Control (P&C) systems

• Successful technical solutions are those that are simple and that address well-defined real problems

• Achieving cost savings

• Reducing project duration

Business Drivers for Process Bus

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P&C System Cost Breakdown

Commissioning24%

Construction21%

Drafting10%

Engineering18%

Materials27%

Labour73%

Total Project Budget (Hard-Wired)of $407,000

Construction7%

Engineering10%

Drafting4%

Commissioning13%

Equivalent Project Budget (Process Bus)of $407,000

Labour73%

Labour34%

Materials42%

Savings25%

“The next generation P&C system should replace copper wiring by placing electronic

modules throughout the switchyard and using fiber communications for bi-directional

exchange of data”

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Design Principles

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Process Bus System PrinciplesCopper connections - the largest source of variability

and cost:

• Replace custom copper connections with standard, pre-terminated fiber optic connections

• Migrate physical variability of connections into software and fiber connectivity

Before … … After

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Design Principles

> Standard magnetic ITs will be in service for a long time:

– Not dependant on installation of non-conventional ITs, but

– Support non-conventional ITs as market acceptance grows

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Design Principles

Maintain traditional P&C concepts:

– Overlapping and independent zones of protection

– One independent device protecting one zone

– Minimum inter-dependencies

LINE 1ZONE

LINE 2ZONE

XFRM 1ZONE

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Not all the process data is needed by all IEDs. The limited data requirements of each IED are clearly and unambiguously dictated

by the virtually fixed power primary equipment arrangement.

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System Architecture

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System Architecture Process bus Merging Units

installed in the switchyard at direct proximity to HV primary equipment

Provide complete I/O capability for the system

Interface all types of switchgear (CBs+CTs, PTs, free-standing CTs, disconnect and ground switches, sensors)

Data acquisition and outputs only, no processing (future-proof)

Redundant MUs for critical signals

No conventional I/Os in IEDs in relay cabinets

No extra devices in the system (LAN switches, master clocks)

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System Architecture Merging Units connected via

multi-fiber cables (star topology) Fiber cables in trenches, directly

buried when required Merging Units powered via

copper wires integrated in the fiber cable

Prefabricated high-density cable connectors

SwitchyardControlhouse

Outdoorfiber cables

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System Architecture

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Station LAN (IEC 61850 Station Bus)

System Components

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System Components

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Outdoor Mounting Scenarios• External, on a Circuit Breaker• External, on a structure• External on VT, CT marshalling box• Internal, old oil-type Circuit Breaker• Etc.,

• Data sharing• Synchronization• Independence of

devices

Advanced Issues

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Multiple MUs in One Physical Device

Common I/Ohardware

Analog Core

Four independent “digital cores”

Direct point-to-point fiber link to relay

Digital communication with data integrity

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Making the ConnectionThe only tools you

will ever need

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AnalogsDigital InputsDC inputsSSR OutputsForm-C OutputsLatching Output

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Synchronization

IED 3

IED 4Devices stay independent – - no need for a master clock

Merging Unit

Four independent

“digital cores”

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Synchronization

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Summary• Architecture

– Rugged units to interface all switchyard I/O

– Point to point communication to relays– Relays as synch masters– Multiple MUs inside a physical device

• Comprehensive all-fiber P&C system• Reduces installation & maintenance cost• Intuitive & practical IEC 61850 process bus• Modular & scalable• Improves quality, reliability