Energy Profiles: BACnet Load Control, 61850, OpenADR, ZigBee, and C12.19

David HolmbergBACnet Utility Integration Working Group leader

OASIS Profiles in EnergyJune 9, 2009

Energy Profiles in context• Service levels (the control strategy)• Communications (info model)– Load control (or price) communications– Feedback to the grid side– Or bids

BACnet background• The BACnet protocol is all about building

controls and designed for monitoring systems, managing schedules, trending, controlling loads.

• BACnet has metering specific tools like the Accumulator and Pulse Converter objects.

• Ongoing work on a generic Meter object to allow for interoperable access from meters or meter gateways.

• BACnet has a specific Load Control object (LCO)

BACnet Load Control object• The Load Control object (LCO) provides an interface to

execute predetermined control actions and to view current load shed status (example)

• Load Control object does not specify how the electrical consumption is to be reduced or how consumption baselines should be determined.

• Three parameters may be written: – Requested_Shed_Level– Start_Time – Shed_Duration

• LCO can be in one of four states: inactive, shed pending, shed compliant, or shed non-compliant.

• can be linked in a distributed, hierarchical fashion for controlling complex combinations of electrical loads

Using the LCO• LCO “Requested_Shed_Level” can be a level or % shed or kW

shed.• LCO provides a way to communicate value to sub-systems/

devices, rather than commanding them with specific control actions.

• LCO provides for status to give feedback—will you shed? Are you shedding? (discovery, forecasting and DG)

• Implementing Prices-to-devices• Do we use the LCO with a chiller? Isn’t it better to raise zone

temperature and let the existing control algorithm reduce energy consumption? – Temp Control (LC in terms of “don’t melt the chocolate”)– Acceptable lighting reductions (service level)– For unimportant loads (the pool pump) I’m not going to tell it to go to

50% power• Has to be in the context of building operation.

ZigBee SEP• ZigBee SEP details load control and price event

signals for AMI• DR and LC Cluster, Apdx. D

– Load Control Event: issuerID, DeviceClass (to allow directing event, e.g., HVAC, pool pump, lighting, EV, water heater, appliance), startTime, Duration, CriticalityLevel, TempOffset, TempSetpoint, AverageLoadAdjustmentPercentage, DutyCycle

– CancelEvent commands also

• Price Cluster– Get and publish price commands– Get Scheduled Prices– PublishPrice format: providerID, Rate class, EventID, current

time, price, units, currency, start time, duration, price ratio, alternate cost delivered.

61850, OpenADR, C12.19• Marty Burns’ cross-analysis of IEC 61850, OpenADR, ANSI

C12.19 and LCO price and DR structures.– “Common Objects for Pricing and Control Communications, EPRI 1018556”

• Begins with 61850 constructs and adds to them to include pieces from other standards.

• Goal: develop real time price rate structures and control signals in IEC 61850 formats for contributions to user groups and standards organizations

• C12.19 Table 11:– Direct load control: command sent to modify the state of control

points. – Schedule: End Device programmed to modify state of control points at

specific dates, recurring dates, period of the week or event detection. – Condition: End Device modifies state based on magnitudes of metered

quantities, price level (active tier), time of the day, period of the year or any other condition based on a Single Line Math expression.

– Prepayment: End Device modifies state based on a remaining credit.

OpenADR cross comparison

• 61850 data classes– Tariff– Schedule– Direct Load Control– Market– Bidder– Bid– Weather– Consumption Event– Energy Efficiency– IAQ