SunSpec Inverter Controls Model SunSpec Alliance Members’ Meeting Jan 2012.
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SunSpec Inverter Controls Model SunSpec Alliance Members’ Meeting Jan 2012
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Transcript of SunSpec Inverter Controls Model SunSpec Alliance Members’ Meeting Jan 2012.
SunSpec Inverter Controls ModelSunSpec Alliance Members’ Meeting Jan 2012
Inverter Controls Model
Defines a model for support of programmed, scheduled and autonomous inverter control operations.
New inverter control modes to be optional on a feature basis, via a set of new SunSpec Device Identifiers (DIDs).
Allows the inverter to offer a set of capabilities to clients and for those clients to discover the capabilities of the inverter and to skip function blocks it does not recognize or implement.
Applies to PV inverters, with or without battery storage.
Based on past and on-going work in various industry and standards bodies, including IEC TC57/WG17, DNP3 User’s Group and EPRI.o Aligns with IEC draft 61850-90-7 and EPRI draft 1023059.
Current Inverter Model
Basic inverter measurements and status; no control operations.
Two maps defined: integer with scale factors and floating point without scale factors. Unique DID for each map.
Inverter model map elements:o AC current and voltages (all phases) and scale factors
o AC power, AC frequency, AC VA, AC VAR, AC PF, AC Energy
o DC current, voltage, power and scale factors
o Temperatures (4) and scale factor
o SunSpec status (enumeration), vendor defined status
o SunSpec event flags (64 bits), vendor defined event flags (128 bits)
Inverter Controls Model Overview
Nameplate Ratings
Basic Settings
Extended Measurements and Status
Controlso Immediate Controls
o Basic Storage
o Pricing Signal
o Static Volt-VAR Arrays
o Frequency-Watt Curve
o Dynamic Reactive Current
o LVRT/HVRT Arrays
o Watt-PF
o Voltage-Watt
o Basic Scheduling
Chained Control Blocks with Defined Device IDs
Nameplate Ratings Read-only values set by inverter manufacturer
o Inverter Ratings (Watt, VA, VAR)
o Storage Ratings (Amps, Ahr, Whr, Max Charge Rate, Max Disch. Rate
Required if any controls blocks are used
Basic Settings
Operating limits and reference values used in control functionso WMax, PRef, VMin, VMax, VAMax, VarMax, VRef, VRefOfs
o MaxWLimPct, ECPNomHz
Default ramp rateso MaxRmpRte
Measurement/setting meaningso PFSign, VarAct, ClcTotVA, ConnectedPhase
Required if any controls blocks are used
Extended Measurements/Status
Inverter present/available
Storage present/available
ECP connection status
Real energy (64-bits)
Apparent energy (64-bits)
Reactive energy by quadrant (64-bits each)
Available VARs
Time source and current time
Required if any controls blocks are used
Immediate Controls
Connect/disconnect from grid
Max power output [curtailment] (% WMax)
Fixed PF (cos(ϕ) + excitation)
Fix VAR (% VarMax)
Plus random time window, reversion time, ramp time
Basic Storage
Setpoints for max charge, max charging VA
Set maximum charge/discharge gradients
Set minimum reserve storage (% max storage)
Status/Measurementso Charge state, state of charge, battery voltage, charge status
Set storage control mode (charge/discharge)
Ramp rateso Power output rate, power input rate
o Random window, reversion time, ramp time for in/out power rates
Grid charge allowed (yes/no)
Pricing Signal
Pricing signal typeo Absolute price
o Relative price
o Price multiplier
o Qualitative (high/medium/low)
Pricing signal value
Random window, reversion time, ramp time
Used with built-in pricing knowledge or pricing schedule
Static Volt-VAR
Curve-based description of responseo Variable number of curves (recommend min 4)
o Variable number of points (recommend min 10)
Curves contain points and filter/ramp valueso Volt-VAR pairs as %VRef and %VarAval
o Low pass filter time (seconds)
o Increment and decrement ramps (%VarAval/min)
o Number of active points in curve
Random time window, reversion time, ramp time
Frequency-Watt
Parameter or curve-based
Parameter methodo Watt reduction gradient
o Start frequency
o Stop frequency
o Hysteresis
Curve-based description of responseo Variable number of curves (recommend min 4)
o Variable number of points (recommend min 10)
Curves contain points and filter/ramp valueso Frequency-Watt pairs as Hertz and %PRef
o Low pass filter time (seconds)
o Increment and decrement ramps (%WMax/min)
o Number of active points in curve
Dynamic Reactive Current Support
Inject additional reactive current based on change in voltage
Upper/lower zone limits, outside which no additional VARs supplied
Upper/lower delta voltages, below which no additional VAR support
Gradient for additional inductive or capacitive current
Filter time for calculating average voltage
Hysteresis voltage
LVRT/HVRT
Curve-base descriptiono Must disconnect curve
o Optional must remain connected curve
o Variable number of points (recommend min 10)
Curves contain pointso Time-Voltage pairs as seconds and %VRef
Min/max service voltage for reconnection
Delay times for reconnection
Watt-Power Factor
Curve-based description of responseo Single curve (infrequently changed control)
o Variable number of points (recommend min 10)
Curve contains points and filter/ramp valueso Watt-PF pairs as %WMax and cos(ϕ) plus PF excitation
o Low pass filter time (seconds)
o Increment and decrement ramps (%PF/min)
o Number of active points in curve
Random time window, reversion time, ramp time
Volt-Watt
Curve-based description of responseo Variable number of curves (recommend min 4)
o Variable number of points (recommend min 10)
Curves contain points and filter/ramp valueso Volt-Watt pairs as %VRef and %WMax
o Low pass filter time (seconds)
o Increment and decrement ramps (%WMax/min)
o Number of active points in curve
Random time window, reversion time, ramp time
Basic Scheduling
Array-based X-Y description of scheduleo Variable number of schedules (recommend min 4)
o Variable number of entries (recommend min 10)
o Variable X meaning (relative time, temperature, price)
o Variable Y meaning (%WMax, PF, price, Volt-VAR array, charge/discharge gradient, VarAval)
Schedules contain X-Y valueso X value as defined by its meaning
o Y value as defined by its meaning
o Repetition flag (none, daily, weekly, monthly, weekdays, weekends)
o Random time window and ramp time
o Number of active entries in schedule
Current Status (2/01/12)
Two working documents: Word doc with explanatory text and spreadsheet with Modbus map details.
Working group meeting weekly (8am PST, Wednesdays).
Completed first pass of proposed Modbus map and explanatory document.
Ready for review by an extended technical audience.
Questions
Bill Randle
AE Solar Energy Headquarters
20720 Brinson Blvd
Bend, OR. 97701
541.323.4441877.312.3832
www.advanced-energy.com/solarenergy
