VOLTTRON In Use: DNP3 and MESA-ESS

Bora Akyol, 8minutenergy Renewables LLC Rob Calvert, ChargePoint / Kisensum

August 22, 2018

DNP3Agent

DNP3Agent is a DER protocol adapter similar to OpenADRVenAgent. It implements a DNP3 Outstation that engages in bidirectional TCP/IP communications with a remote DNP3 Master.

pydnp3 Library

The standard open-source library supporting DNP3 communications is opendnp3, implemented in C++.

Kisensum has now published pydnp3 (https://github.com/ChargePoint/pydnp3), which implements Python bindings for the opendnp3 library.

DNP3Agent is built on pydnp3.

MesaAgent

In 2018, Kisensum contributed a DNP3Agent and MesaAgent to the VOLTTRON platform.

MesaAgent, subclassed from DNP3Agent, adds support for MESA-ESS functions (modes), curves, and schedules.

More to come on MESA in a few slides.

Virtual Utility Application

The VUA is a Python 3 / Django 2 web application that facilitates defining test functions, curves and schedules and sending them to a MESA-ESS Outstation (e.g., MesaAgent).

Kisensum/8minutenergy has published a “Virtual Utility Application” (https://github.com/ChargePoint/vua) that implements a MESA-ESS DNP3 master.

MESA-ESS Specification Overview •  MESA-ESS specification is based on two communication standards:

–  IEC 61850 data model mapped to IEEE 1815 (DNP3) protocol

•  IEC 61850-7-420 data model provides an abstract set of data objects

•  Includes nameplate and operational information for ESS, PVs, Gen Sets, Fuel Cells, and Combined Heat and Power (CHP)

•  Supports the new IEEE 1547 grid codes (e.g. voltage and frequency ride-through, volt-var control, frequency-watt control)

•  Includes additional market-based functions (e.g. Automatic Generation Control (AGC), direct control of charging and discharging, peak power limiting, etc.)

•  Supports scheduling not only of values, such as energy output and charging, but also the grid codes and market functions

•  IEEE 1815 provides the “bits and bytes” protocol for implementations

•  Using IEEE 1815 for the DNP3 and IEEE 1815.1 for basic mapping requirements

•  This mapping forms an IEC 61850/DNP3 Profile

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MESA’s Mission

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Overview of MESA Specifications Gray Developed by MESA and SunSpec

Orange Developed by MESA Alliance •  (Interface #1) MESA-ESS SCADA Specification

with DNP3 Protocol mapped from IEC 61850-7-420:

–  Operational Management –  Monitoring –  Control Functions –  Smart ESS Modes –  Scheduling

•  Control System contains ESS Vendor Applications

•  (Interface #12) SunSpec Inverter Models Map Modbus to the MESA-Device Energy Storage Model:

–  MESA-PCS: Power Conversion System –  MESA-Storage: Energy Storage –  MESA-Meter: Meters

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19 Functions and Modes Supported by MESA-ESS (1) •  Functions

–  Monitoring Function: The ESS provides status, measurements, and other requested data

–  Connect/Disconnect Function: Connect or disconnect (cease to energize) the ESS from the grid at its ECP

•  Emergency Modes

–  High/Low Voltage Ride-Through Mode: The ESS rides through temporary fluctuations in voltage at the PCC

–  High/Low Frequency Ride-Through Mode: The ESS rides through temporary fluctuations in frequency at the PCC

–  Dynamic Reactive Current Support Mode: The ESS reacts against rapid voltage changes to provide dynamic system stabilization

–  Frequency-Watt Emergency Mode: The ESS responds to large frequency excursions during H/LFRT events at a referenced ECP by changing its charging or discharging rate

•  Real Power Modes

–  Real Power Charge/Discharge Mode: Set the ESS to charge or discharge real power at the referenced ECP

–  Limit Real Power Discharging or Charging Mode: Limits the discharging or charging level of the ESS based on the referenced ECP

–  Load Following (Peak Power Limiting) Mode: The discharging real power output of the ESS follows the load at the Referenced ECP if it starts to exceed a target power level.

–  Generation Following Mode: The discharging or charging of the ESS follows the generation at the referenced ECP if it starts to exceed a target power level.

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Functions and Modes Supported by MESA-ESS (2) •  Real Power Modes (Continued)

–  Real Power Smoothing Mode: The ESS produces or absorbs real power in order to smooth the changes in the power level of the referenced ECP.

–  Volt-Watt Mode: The ESS responds to changes in the voltage at the referenced ECP by changing its charging or discharging rate

–  Automatic Generation Control (AGC) Mode: The ESS responds to raise and lower power level requests to provide frequency regulation support

–  Charge-By Time Management Mode: The ESS determines when to charge so long as it meets its State of Charge level obligation by the Charge-By date and time in the most cost-effective manner or based on owner preferences

–  Frequency-Watt Smoothing Mode: The ESS responds to changes in frequency at the referenced ECP by changing its charging or discharging rate based on frequency deviations from nominal, as a means for countering those frequency deviations

•  Reactive Power Modes –  Fixed Power Factor Mode: The ESS power factor is set to a fixed value. –  Volt-Var Control Mode: The ESS responds to changes in voltage at the referenced ECP by supplying or absorbing

vars in order to maintain the desired voltage level –  Watt-Power Factor Mode: The ESS responds to changes in power at the referenced ECP by changing its power

factor –  Power Factor Correction Mode: The ESS supplies or absorbs vars to hold the power factor constant at the

referenced ECP.

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Additional Capabilities Supported by MESA-ESS (3) SchedulingofPowerSettingsandModes

TheESSfollowstheschedulewhichconsistsofatimeoffset(specifiedasanumberofseconds)fromthestartofthescheduleandisassociatedwith: ·  apowersystemsetting ·  theenabling/disablingofanoperatingmode ·  apricesignal

HistoricalInformation Detailedmeasurementandperformancedatawhichmaybevaluabletorecordinanoperationalhistorian

EstablishRampRates Inadditiontothedefaultramprate,theESSmaysupportmultiplerampratesthatreflectdifferentconditions.

Soft-StartReconnection Useramprateorrandomtimewithinwindowwhenreconnecting Permitreconnection Utilityorotherauthoritypermitsreconnection,butreconnectionmayormaynotstartatthat

time

Microgridseparationcontrol Processfornormalseparation,emergencyseparation,andreconnection

ProvideBlackStartCapability Abilitytostartwithoutgridpower,andtheabilitytoaddsignificantloadinsegmentedgroups

ProvideBackupPower Abilitytoprovidepowertolocalloadswhennotconnectedtothegrid

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8minutenergy uses MESA-ESS for controlling energy storage