Simulation Subsystem

The simulation subsystem includes a set of device simulators and a clock that can run faster (or slower) than real time. It can be used to test VOLTTRON agents or drivers. It could be particularly useful when simulating multi-agent and/or multi-driver scenarios.

The source code for the agents and drivers comprising this subsystem resides in the https://github.com/VOLTTRON/volttron-applications github repository.

This subsystem is designed to be extended easily. Its initial delivery includes a set of simulated energy devices that report status primarily in terms of power (kilowatts) produced and consumed. It could easily be adapted, though, to simulate and report data for devices that produce, consume and manage resources other than energy.

Three agents work together to run a simulation:

  1. SimulationClockAgent. This agent manages the simulation’s clock. After it has been supplied with a start time, a stop time, and a clock-speed multiplier, and it has been asked to start a simulation, it provides the current simulated time in response to requests. If no stop time has been provided, the SimulationClockAgent continues to manage the simulation clock until the agent is stopped. If no clock-speed multiplier has been provided, the simulation clock runs at normal wallclock speed.
  2. SimulationDriverAgent. Like MasterDriverAgent, this agent is a front-end manager for device drivers. It handles get_point/set_point requests from other agents, and it periodically “scrapes” and publishes each driver’s points. If a device driver has been built to run under MasterDriverAgent, with a few minor modifications (detailed below) it can be adapted to run under SimulationDriverAgent.
  3. SimulationAgent. This agent configures, starts, and reports on a simulation. It furnishes a variety of configuration parameters to the other simulation agents, starts the clock, subscribes to scraped driver points, and generates a CSV output file.

Four device drivers have been provided:

  1. storage (simstorage). The storage driver simulates an energy storage device (i.e., a battery). When it receives a power dispatch value (positive to charge the battery, negative to discharge it), it adjusts its charging behavior accordingly. Its reported power doesn’t necessarily match the dispatch value, since (like an actual battery) it stays within configured max-charge/max-discharge limits, and its power dwindles as its state of charge approaches a full or empty state.
  2. pv (simpv). The PV driver simulates a photovoltaic array (solar panels), reporting the quantity of solar power produced. Solar power is calculated as a function of (simulated) time, using a data file of incident-sunlight metrics. A year’s worth of solar data has been provided as a sample resource.
  3. load (simload). The load driver simulates the behavior of a power consumer such as a building, reporting the quantity of power consumed. It gets its power metrics as a function of (simulated) time from a data file of power readings. A year’s worth of building-load data has been provided as a sample resource.
  4. meter (simmeter). The meter driver simulates the behavior of a circuit’s power meter. This driver, as delivered, is actually just a shell of a simulated device. It’s able to report power as a function of (simulated) time, but it has no built-in default logic for deciding what particular power metrics to report.

Linux Installation

The following steps describe how to set up and run a simulation. They assume that VOLTTRON / volttron and VOLTTRON / volttron-applications repositories have been downloaded from github, and that Linux shell variables $VOLTTRON_ROOT and $VOLTTRON_APPLICATIONS_ROOT point at the root directories of these repositories.

First, create a soft link to the applications directory from the volttron directory, if that hasn’t been done already:

$ cd $VOLTTRON_ROOT
$ ln -s $VOLTTRON_APPLICATIONS_ROOT applications

With VOLTTRON running, load each simulation driver’s configuration into a “simulation.driver” config store:

$ export SIMULATION_DRIVER_ROOT=$VOLTTRON_ROOT/applications/kisensum/Simulation/SimulationDriverAgent

$ vctl config store simulation.driver simload.csv $SIMULATION_DRIVER_ROOT/simload.csv --csv
$ vctl config store simulation.driver devices/simload $SIMULATION_DRIVER_ROOT/simload.config

$ vctl config store simulation.driver simmeter.csv $SIMULATION_DRIVER_ROOT/simmeter.csv --csv
$ vctl config store simulation.driver devices/simmeter $SIMULATION_DRIVER_ROOT/simmeter.config

$ vctl config store simulation.driver simpv.csv $SIMULATION_DRIVER_ROOT/simpv.csv --csv
$ vctl config store simulation.driver devices/simpv $SIMULATION_DRIVER_ROOT/simpv.config

$ vctl config store simulation.driver simstorage.csv $SIMULATION_DRIVER_ROOT/simstorage.csv --csv
$ vctl config store simulation.driver devices/simstorage $SIMULATION_DRIVER_ROOT/simstorage.config

Install and start each simulation agent:

$ export SIMULATION_ROOT=$VOLTTRON_ROOT/applications/kisensum/Simulation
$ export VIP_SOCKET="ipc://$VOLTTRON_HOME/run/vip.socket"

$ python scripts/install-agent.py \
    --vip-identity simulation.driver \
    --tag          simulation.driver \
    --agent-source $SIMULATION_ROOT/SimulationDriverAgent \
    --config       $SIMULATION_ROOT/SimulationDriverAgent/simulationdriver.config \
    --force \
    --start

$ python scripts/install-agent.py \
    --vip-identity simulationclock \
    --tag          simulationclock \
    --agent-source $SIMULATION_ROOT/SimulationClockAgent \
    --config       $SIMULATION_ROOT/SimulationClockAgent/simulationclock.config \
    --force \
    --start

$ python scripts/install-agent.py \
    --vip-identity simulationagent \
    --tag          simulationagent \
    --agent-source $SIMULATION_ROOT/SimulationAgent \
    --config       $SIMULATION_ROOT/SimulationAgent/simulationagent.config \
    --force \
    --start

SimulationAgent Configuration Parameters

This section describes SimulationAgent’s configurable parameters. Each of these has a default value and behavior, allowing the simulation to be run “out of the box” without configuring any parameters.

Type Param Name Data Type Default Comments
General agent_id str simulation  
General heartbeat_period int sec 5  
General sim_driver_list list of str [simload, simmeter, simpv, simstorage] Allowed keywords are simload, simmeter, simpv, simstorage.
Clock sim_start datetime str 2017-02-02 13:00:00  
Clock sim_end datetime str None If None, sim doesn’t stop.
Clock sim_speed float sec 180.0 This is a multiplier, e.g. 1 sec actual time = 180 sec sim time.
Load load_timestamp_column_header str local_date  
Load load_power_column_header str load_kw  
Load load_data_frequency_min int min 15  
Load load_data_year str 2015  
Load load_csv_file_path str ~/repos/volttron-applications/kisensum/ Simulation/SimulationAgent/data/load_an d_pv.csv ~ and shell variables in the pathname will be expanded. The file must exist.
PV pv_panel_area float m2 50.0  
PV pv_efficiency float 0.0-1.0 0.75  
PV pv_data_frequency_min int min 30  
PV pv_data_year str 2015  
PV pv_csv_file_path str ~/repos/volttron-applications/kisensum/ Simulation/SimulationAgent/data/nrel_pv _readings.csv ~ and shell variables in the pathname will be expanded. The file must exist.
Storage storage_soc_kwh float kWh 30.0  
Storage storage_max_soc_kwh float kWh 50.0  
Storage storage_max_charge_kw float kW 15.0  
Storage storage_max_discharge_kw float kW 12.0  
Storage storage_reduced_charge_soc _threshold float 0.0-1.0 0.80 Charging will be reduced when SOC % > this value.
Storage storage_reduced_discharge_s oc_threshold float 0.0-1.0 0.20 Discharging will be reduced when SOC % < this value.
Dispatch storage_setpoint_rule str keyword oscillation See below.
Dispatch positive_dispatch_kw float kW >= 0.0 15.0  
Dispatch negative_dispatch_kw float kW <= 0.0 -15.0  
Dispatch go_positive_if_below float 0.0-1.0 0.1  
Dispatch go_negative_if_above float 0.0-1.0 0.9  
Report report_interval int seconds 14  
Report report_file_path str $VOLTTRON_HOME/run/simulation_out.csv ~ and shell variables in the pathname will be expanded. If the file exists, it will be overwritten.

The oscillation setpoint rule slowly oscillates between charging and discharging based on the storage device’s state of charge (SOC):

If SOC < (``go_positive_if_below`` * ``storage_max_soc_kwh``):
    dispatch power = ``positive_dispatch_kw``

If SOC > (``go_negative_if_above`` * ``storage_max_soc_kwh``)
    dispatch power = ``negative_dispatch_kw``

Otherwise:
    dispatch power is unchanged from its previous value.

The alternate setpoint rule is used when storage_setpoint_rule has been configured with any value other than oscillation. It simply charges at the dispatched charging value (subject to the constraints of the other parameters, e.g. storage_max_discharge_kw):

dispatch power = ``positive_dispatch_kw``

Driver Parameters and Points

Load Driver

The load driver’s parameters specify how to look up power metrics in its data file.

Type Name Data Type Default Comments
Param/Point csv_file_path string   This parameter must be supplied by the agent.
Param/Point timestamp_column_header string local_date  
Param/Point power_column_header string load_kw  
Param/Point data_frequency_min int 15  
Param/Point data_year string 2015  
Point power_kw float 0.0  
Point last_timestamp datetime    

Meter Driver

Type Name Data Type Default Comments
Point power_kw float 0.0  
Point last_timestamp datetime    

PV Driver

The PV driver’s parameters specify how to look up sunlight metrics in its data file, and how to calculate the power generated from that sunlight.

Type Name Data Type Default Comments
Param/Point csv_file_path string   This parameter must be supplied by the agent.
Param/Point max_power_kw float 10.0  
Param/Point panel_area float 50.0  
Param/Point efficiency float 0.75  
Param/Point data_frequency_min int 30  
Param/Point data_year string 2015  
Point power_kw float 0.0  
Point last_timestamp datetime    

Storage Driver

The storage driver’s parameters describe the device’s power and SOC limits, its initial SOC, and the SOC thresholds at which charging and discharging start to be reduced as its SOC approaches a full or empty state. This reduced power is calculated as a straight-line reduction: charging power is reduced in a straight line from reduced_charge_soc_threshold to 100% SOC, and discharging power is reduced in a straight line from reduced_discharge_soc_threshold to 0% SOC.

Type Name Data Type Default Comments
Param/Point max_charge_kw float 15.0  
Param/Point max_discharge_kw float 15.0  
Param/Point max_soc_kwh float 50.0  
Param/Point soc_kwh float 25.0  
Param/Point reduced_charge_soc_threshold float 0.8  
Param/Point reduced_discharge_soc_threshold float 0.2  
Point dispatch_kw float 0.0  
Point power_kw float 0.0  
Point last_timestamp datetime    

Working with the Sample Data Files

The Load and PV simulation drivers report power readings that are based on metrics from sample data files. The software distribution includes sample Load and PV files containing at least a year’s worth of building-load and sunlight data.

CSV files containing different data sets of load and PV data can be substituted by specifying their paths in SimulationAgent’s configuration, altering its other parameters if the file structures and/or contents are different.

Load Data File

load_and_pv.csv contains building-load and PV power readings at 15-minute increments from 01/01/2014 - 12/31/2015. The data comes from a location in central Texas. The file’s data columns are: utc_date, local_date, time_offset, load_kw, pv_kw. The load driver looks up the row with a matching local_date and returns its load_kw value.

Adjust the following SimulationAgent configuration parameters to change how load power is derived from the data file:

  • Use load_csv_file_path to set the path of the sample data file
  • Use load_data_frequency_min to set the frequency of the sample data
  • Use load_data_year to set the year of the sample data
  • Use load_timestamp_column_header to indicate the header name of the timestamp column
  • Use load_power_column_header to indicate the header name of the power column

PV Data File

nrel_pv_readings.csv contains irradiance data at 30-minute increments from 01/01/2015 - 12/31/2015, downloaded from NREL’s National Solar Radiation Database, https://nsrdb.nrel.gov. The file’s data columns are: Year, Month, Day, Hour, Minute, DHI, DNI, Temperature. The PV driver looks up the row with a matching date/time and uses its DHI (diffuse horizontal irradiance) to calculate the resulting solar power produced:

power_kw = irradiance * panel_area * efficiency / elapsed_time_hrs

Adjust the following SimulationAgent configuration parameters to change how solar power is derived from the data file:

  • Use pv_csv_file_path to set the path of the sample data file
  • Use pv_data_frequency_min to set the frequency of the sample data
  • Use pv_data_year to set the year of the sample data
  • Use pv_panel_area and pv_efficiency to indicate how to transform an irradiance measurement in wh/m2 into a power reading in kw.

If a PV data file will be used that has a column structure which differs from the one in the supplied sample, an adjustment may need to be made to the simpv driver software.

Running the Simulation

One way to monitor the simulation’s progress is to look at debug trace in VOLTTRON’s log output, for example:

2017-05-01 15:05:42,815 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:05:42.815484 Initializing drivers
2017-05-01 15:05:42,815 (simulationagent-1.0 9635) simulation.agent DEBUG:  Initializing Load: timestamp_column_header=local_date, power_column_header=load_kw, data_frequency_min=15, data_year=2015, csv_file_path=/Users/robcalvert/repos/volttron-applications/kisensum/Simulation/SimulationAgent/data/load_and_pv.csv
2017-05-01 15:05:42,823 (simulationagent-1.0 9635) simulation.agent DEBUG:  Initializing PV: panel_area=50, efficiency=0.75, data_frequency_min=30, data_year=2015, csv_file_path=/Users/robcalvert/repos/volttron-applications/kisensum/Simulation/SimulationAgent/data/nrel_pv_readings.csv
2017-05-01 15:05:42,832 (simulationagent-1.0 9635) simulation.agent DEBUG:  Initializing Storage: soc_kwh=30.0, max_soc_kwh=50.0, max_charge_kw=15.0, max_discharge_kw=12.0, reduced_charge_soc_threshold = 0.8, reduced_discharge_soc_threshold = 0.2
2017-05-01 15:05:42,844 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:05:42.842162 Started clock at sim time 2017-02-02 13:00:00, end at 2017-02-02 16:00:00, speed multiplier = 180.0
2017-05-01 15:05:57,861 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:05:57.842164 Reporting at sim time 2017-02-02 13:42:00
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simload/power_kw = 486.1
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simpv/power_kw = -0.975
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/dispatch_kw = 0.0
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/last_timestamp = 2017-02-02 13:33:00
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/power_kw = 0.0
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/soc_kwh = 30.0
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  net_power_kw = 485.125
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:  report_time = 2017-02-02 13:42:00
2017-05-01 15:05:57,862 (simulationagent-1.0 9635) simulation.agent DEBUG:          Setting storage dispatch to 15.0 kW
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:06:12.869471 Reporting at sim time 2017-02-02 14:30:00
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simload/power_kw = 467.5
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simpv/power_kw = -5.925
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/dispatch_kw = 15.0
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/last_timestamp = 2017-02-02 14:27:00
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/power_kw = 15.0
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/soc_kwh = 43.5
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  net_power_kw = 476.575
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:  report_time = 2017-02-02 14:30:00
2017-05-01 15:06:12,901 (simulationagent-1.0 9635) simulation.agent DEBUG:          Setting storage dispatch to 15.0 kW
2017-05-01 15:06:27,931 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:06:27.907951 Reporting at sim time 2017-02-02 15:15:00
2017-05-01 15:06:27,931 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simload/power_kw = 474.2
2017-05-01 15:06:27,931 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simpv/power_kw = -11.7
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/dispatch_kw = 15.0
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/last_timestamp = 2017-02-02 15:03:00
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/power_kw = 5.362
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/soc_kwh = 48.033
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  net_power_kw = 467.862
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:  report_time = 2017-02-02 15:15:00
2017-05-01 15:06:27,932 (simulationagent-1.0 9635) simulation.agent DEBUG:          Setting storage dispatch to -15.0 kW
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG: 2017-05-01 15:06:42.939181 Reporting at sim time 2017-02-02 16:00:00
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simload/power_kw = 469.5
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simpv/power_kw = -9.375
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/dispatch_kw = -15.0
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/last_timestamp = 2017-02-02 15:57:00
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/power_kw = -12.0
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  devices/simstorage/soc_kwh = 37.233
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  net_power_kw = 448.125
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:  report_time = 2017-02-02 16:00:00
2017-05-01 15:06:42,971 (simulationagent-1.0 9635) simulation.agent DEBUG:          Setting storage dispatch to -15.0 kW
2017-05-01 15:06:58,001 (simulationagent-1.0 9635) simulation.agent DEBUG: The simulation has ended.

Report Output

The SimulationAgent also writes a CSV output file so that simulation results can be reported by spreadsheets, for example this graph of the simulated storage device following an oscillating dispatch:

../_images/1-simulation-out.jpg

Using the Simulation Framework to Test a Driver

If you’re developing a VOLTTRON driver, and you intend to add it to the drivers managed by MasterDriverAgent, then with a few tweaks, you can adapt it so that it’s testable from this simulation framework.

As with drivers under MasterDriverAgent, your driver should be go in a .py module that implements a Register class and an Interface class. In order to work within the simulation framework, simulation drivers need to be adjusted as follows:

  • Place the module in the interfaces directory under SimulationDriverAgent.
  • The module’s Register class should inherit from SimulationRegister.
  • The module’s Interface class should inherit from SimulationInterface.
  • If the driver has logic that depends on time, get the simulated time by calling self.sim_time().

Add files with your driver’s config and point definitions, and load them into the config store:

$ vctl config store simulation.driver \
    yourdriver.csv \
    $VOLTTRON_ROOT/applications/kisensum/Simulation/SimulationDriverAgent/yourdriver.csv --csv
$ vctl config store simulation.driver \
    devices/yourdriver \
    $VOLTTRON_ROOT/applications/kisensum/Simulation/SimulationDriverAgent/yourdriver.config

To manage your driver from the SimulationAgent, first add the driver to the sim_driver_list in that agent’s config:

"sim_driver_list": ["simload", "simpv", "simstorage", "youdriver"]

Then, if you choose, you can also revise SimulationAgent’s config and logic to scrape and report your driver’s points, and/or send RPC requests to your driver.

For Further Information

If you have comments or questions about this simulation support, please contact Rob Calvert at Kisensum, Inc.: