A grid-aware co-simulation platform for the design and optimization of electric vehicle charging infrastructure. Paper: https://doi.org/10.1109/TSG.2023.3339374

Quickstart

Jump to requirements.
Jump to how to run.

Authors

Emmanuel Balogun (Project lead): ebalogun@stanford.edu, Lily Buechler: ebuech@stanford.edu

Contribution

We welcome all contributions to the project, including documentation and feature improvements, etc. Please see the CONTRIBUTING.md file for more details.

Correspondence

For more detailed questions, potential collaborations, suggestions and discussions, or assistance that cannot be done directly on github, please reach out to our email.

Requirements

1. See requirements.txt or environment.yml for required packages. The environment.yml file can be used to create a new conda environment with the required packages. To create a new environment using conda env create --name <your env name> -f environment.yml OR if using pip, use pip install -r requirements.txt. If both do not work, then install packages listed in the environment manually.

2. Arras-energy (SLAC) GridLAB-D installation (master branch). See repository here for details. This is required for the power grid co-simulation functionality. This is not necessary if one does not consider the power system voltage impacts.

3. Gurobi License [recommended]. Free (educational) or commercial Gurobi Licenses can be obtained here

4. MOSEK License [optional if Gurobi is installed]. Free (educational) or commercial MOSEK License can be obtained here

Folder descriptions

data/ambient_data

Hosts ambient temperature data for capturing the effects of environmental conditions on subsystems, such as battery, transformers, charging stations.

data/base_load_data

Includes existing base case building/home load (usually uncontrollable) within the distribution grid. This work uses proprietary Pecan Street Data. Below is an exmaple data prototype for the base load data. Note that column fields are case-sensitive. The data used in the original paper has a minute resolution, as is the power system simulation. A csv file with the data prototype is also provided in base_load_data/data_use.csv. The fields: month, day, and hour are indexed from 1. For example 1 - January, 12 - December. The fields: minute and second are indexed from 0. For example 0 - 59. The rest of the columns represented by numbers are anonymized building loads in kilo-watts (kW). For the paper, the base_load_data/data_use.csv contained the actual data from Pecan Street, but unfortunately cannot be shared due to proprietary data rights. However, there are free versions of Pecan Street data that can be used within the plaform by simply replacing the csv file with the appropriate load data file.

data/elec_rates

Includes .csv files for electricity Time-of-use (TOU) rates. The input data prototype for electricity rates is shown below. User must upload a normal full-year sized data (for 365 days) to avoid any errors.

The data required must be in the format shown above. If you upload your own electricity rate data, navigate to charging_sim/configs/prices.json and modify the data_path field to ensure that the data_path field matches the uploaded custom price data. The electricityPrices.py module will read the time-of-use (TOU) price data and sample prices during optimization and simulation. The data should be one full year of TOU rate prices at 15 minute resolution. The electricityPrices.py module can also help with downscaling the data to 15 minute resolution if the data is at a much coarser resolution. The module will save the downscaled data in the elec_rates folder.

data/solar_data

solar_data folder includes solar irradiance data for capturing the effects of environmental conditions on overall system cost. Default data for solar irradiance is from the National Solar Radiation Database (NSRDB) for the San Francisco Bay Area. The data prototype is from the National Renewable Energy Laboratory (NREL) and is shown below. Note that column fields are case-sensitive. If you upload your own solar irradiance data, navigate to charging_sim/configs/solar.json and modify the data_path field to ensure that the data_path field matches the uploaded custom solar data.

Month labels are indexed from 1 to 12, inclusive; 1 - January, 12 - December. The original data is in hourly resolution. The EV-EcoSim data prototype is in 15 minute intervals by default, with irradiance oversampled 4 times from hourly dataset. The GHI represents the "Global Horizontal Irradiance" in W/m^2, which is the total amount of shortwave radiation received from above by a surface horizontal to the ground.

batt_sys_identification

Battery system identification module. Hosts the class for generating battery system identification parameters from experimental data. This module leverages a genetic algorithm to optimize the battery model parameters. The battery model is a 2nd order RC Equivalent circuit model (ECM). One can use this module to generate custom NMC battery parameters by uploading experimental data to the batt_sys_identification/data folder and running the module. The module will generate a .csv file with the battery parameters in the batt_sys_identification folder. The data prototype is shown below. Note that column fields are case-sensitive.

The module will save a new .csv file with an additional field for the corrected open circuit voltage (OCV) values; this field (column) will be labelled ocv_corr within the new battery data csv, including the existing columns as shown in the data prototype above.

Once the battery parameters are generated, they can be used in the data/battery_data folder and charging_sim/configs/battery.json can be modified so the model runs using the new custom parameters.

The image below shows the battery model error (MAPE) for the NMC battery model parameters generated from the module for 3 different sample cells over 10 different trials. The model is trained for only 40 generations (or iterations) of the genetic algorithm with a population of 10.

charging_sim

This folder encompasses the implementation of the physical modules, including:

• battery.py - Battery cell module.
• batteryAgingSim.py - Battery aging module.
• batterypack.py - Battery pack module.
• chargingStation.py - Charging station module.
• clock.py - Clock module.
• controller.py - Controller module.
• electricityPrices.py - Electricity prices module
• node.py - Node module (for centralized DER control and optimization).
• optimization.py - Optimization module.
• orchestrator.py - Simulation orchestrator module.
• simulate.py - Offline DER control optimization for cost minimization (this is run for offline mode (no state feedback)).
• solar.py - Solar PV module.
• transformer.py - Transformer module.
• utils.py - Hosts utility functions used by some modules.

There also contains the configs folder under the charging_sim folder. The configs folder which includes the configuration files for all the relevant modules, such as battery, transformer, solar, clock modules, etc.

DLMODELS

This includes legacy load forecasts models developed (not needed).

feeders

Library of IEEE test feeders and PNNL taxonomy feeders for distribution systems in the GridLAB-D .glm format. IEEE feeders have spot loads specified at primary distribution level. PNNL taxonomy feeders have spot loads specified at primary or secondary distribution level.

feeder_population

Scripts for populating base feeder models with time-varying loads and resources using the load data in base_load_data. feeder_population.py generates the necessary files for a co-simulation run based on the parameters specified in test_cases/{CASE_NAME}/feeder_population/config.txt. Feeder population requires residential load data not included in repo (limited access) due to proprietary data rights. However, there are free versions of Pecan Street data that may be replaced in the base_load_data folder; file should be named data_use.csv.

test_cases

Co-simulation cases.

base_case- Reads voltage from GridLAB-D and writes power injections at each timestep (no EV charging or DER). battery - base_case plus transformer thermal model plus DER integration (included battery and solar).

analysis

Scripts for plotting and analysis of co-simulation results. Includes post optimization and simulation cost calculation modules and voltage impacts on the distribution grid.

plot_results.py - This module is used post-simulation to parse the voltages from the power-simulation to calculate the percentage voltage violations per ANSI C84.1. The file also generates voltage distribution plots. A user can modify the SIMULATION_FOLDER variable which is the string of the path where the powerflow simulation output voltages at each node exist.

load_post_opt_costs.py - This module calculates the levelized cost of energy and populates into tables/cost matrices, which are saved in the respective files and folders. The module also generates plots for the cost analysis.

cost_analysis.py - This module contains the CostEstimator class, which estimates the cost of the different grid and DER components from the simulation.

How to run

For quick-run, it is recommended to use WSL2 (Linux) or MacOS All Native Windows from windows 11 come with WSL2 and you can install your preferred distro (Ubuntu recommended). Older windows users can install WSL2. See here for more details. Read requirements for how to setup the environment and skip to item #3.

1. If you do not have conda installed and want to use conda, please follow the instructions here to install conda.

2. Create a new environment using conda env create --name <your env name> -f environment.ymlOR install packages listed in the environment manually. You can also use the requirements.txt file and pip to install the required packages using the command pip install -r requirements.txt.

3. Ensure gridlabd is installed by following recommended installation method if using the online (MPC) power system co-simulation functionality.

4. Open the user_inputs.json file in the root folder and change the opt_solver field to your either GUROBI or MOSEK, depending on the solver you have installed and have a license for.

5. For offline (One-shot) optimization simulation (Does not require GridLAB-D install):

   • If using Unix based system or Windows Subsystem for Linux (WSL): Modify the fields in the user_inputs.json file as needed. To open WSL, you can open the command line interface or terminal and type wsl Once the fields are modified as desired, run python3 evecosim.py --mode=oneshot or python3 evecosim.py --mode oneshot or python3 evecosim.py in the root directory. This will run the simulation and generate the results in the results folder under the analysis directory. After which the platform will generate the cost analysis plots and tables in the analysis folder.
   • If using Native Windows: TODO

6. For online MPC battery test case (Requires GridLAB-D install):

   • If using Unix based system or Windows Subsystem for Linux (WSL) [RECOMMENDED]: Open the user_inputs.json file in the root folder and modify the parameters as needed. The prepopulated fields can be modified. To open WSL, you can open the command line interface or terminal and type wsl. Once the fields are modified as desired, and you are in the project root directory, in the terminal, type: python3 evecosim.py --mode=mpc-grid or python3 evecosim.py --mode mpc-grid and let the simulation run.

   • If using Native Windows: Navigate to test_cases/battery/feeder_population and run feeder_population_collocated.py for collocated (DEFAULT) case or feeder_population_centralized.py. This uses the test_cases/battery/feeder_population/config.txt settings to prepare the power system and populate the secondary distribution network with time-varying base loads, EV charging stations, Distributed Energy Resources (DERs - Solar, Storage), and required transformers.

     • Once confirmed that feeder_population_<CASE_TYPE>.py (CASE_TYPE is either collocated or centralized but only collocated is supported at this time) has run successfully and generates the required IEEE123_secondary.glm and IEEE123_populated.glm files, you are done with the initial pre-simulation run preparation.
     • Now navigate one level of out /feeder_population and run scenarios.py using python3 scenarios.py or gridlabd python scenarios.py (recommended).

7. For base case (Requires GridLAB-D install):

   • If using Unix based system or Windows Subsystem for Linux (WSL) [RECOMMENDED]: Make sure you are in the project root directory and run python3 evecosim.py --mode base-case-grid or python3 evecosim.py --mode=base-case-grid. The base-case simulation without any EV Charging nor Distrbuted Energy Resources will run. Results will be in the test_cases/base_case folder.

   • If using Native Windows

     • Navigate to ./test_cases/base_case/feeder_population and run feeder_population.py. This uses the ./test_cases/base_case/feeder_population/config.txt settings to prepare the power system and populate the secondary distribution network
       with time-varying base loads
     • Navigate back one directory to ./test_cases/base_case and run master_sim.py using python3 master_sim.py

Post-simulation analysis

• This is done with the modules in the analysis folder. Please see the analysis folder section for more details.

Acknowledgements

This work was supported in part by Stanford Bits and Watts, Portland General Electric, Chevron Energy Fellowship, and Siemens Technology.