Welcome to the Power and Energy Storage Systems Toolbox. This is the PSTess README. Please refer to the table of contents below to help you navigate.
Current release version: 1.1
Release date: February, 2024
For issues and feedback, we would appreciate it if you could use the "Issues" feature of this repository. This helps others join the discussion and helps us keep track of and document issues.
Entity account @sandia.gov: snl-pstess
Project maintainer (Ryan Elliott) @sandia.gov: rtellio
Project co-maintainer (Hyungjin Choi) @sandia.gov: hchoi
The development of PSTess was a collaborative effort between Sandia National Laboratories and Montana Tech. We thank Dr. Daniel Trudnowski and Tam Nguyen for their contributions.
PSTess is an open-source, MATLAB-based toolbox for dynamic simulation and analysis of power systems with utility-scale, inverter-based energy storage systems (ESS). Of course, it can also be used to study conventional power systems. PSTess is a fork of the Power System Toolbox, called PST for short. It is based on PST v3.0, released by Rensselaer Polytechnic Institute (RPI) in August of 2020. The major differences between the two packages are described below. For a detailed description of the modifications made to PST source files, see the CHANGELOG.
- ess: energy storage device model with reactive modulation capability
- ess_sud: user-defined energy storage control model; the pipeline has been customized by Montana Tech
- lsc: linear time-varying (LTV) synchronizing torque controller (for use with ess)
- pwrmod: constant power (or current) injection model
- ivmmod: experimental voltage behind reactance converter model (primarily for studying grid-forming inverters)
- Global variables: all global variables have been reorganized into a
common struct, called
g - Batch processing: a new mode of operation has been added to modify application-wide behavior when performing multiple simulation or analysis runs (see get_dypar)
- Error statements: all errors and warnings issued by the application have been edited to be more specific, consistent, and useful
- Dynamic brake insertions: y_switch has been updated to support
three-phase resistive shunt insertions (e.g., for modeling the Chief
Joseph Brake); this option is now available as
f_type = 8 - Linearization routine: svm_mgen has been redesigned around the central difference method for improved accuracy; the surrounding code has also been modified to better track the time-domain simulation procedure in s_simu
This work was supported by the U.S. DOE Energy Storage Program within the Office of Electricity. The authors would like to thank Dr. Imre Gyuk, Director of Energy Storage Research.
This toolbox owes a great deal to the original developers of PST: Drs. Joe Chow, Kwok Cheung, and Graham Rogers. We thank them for their contributions and for their generosity in releasing PST under the MIT license, enabling others to build upon the foundation they created. See the NOTICE file in this repository for details about the PST license.
Before working with PSTess, please see the documentation listed
under the man directory of this repository. In addition, the
CHANGELOG includes detailed information about changes made to PST
functions and scripts in the creation of PSTess.
To set the PSTess path and or working data file utilized in batch
mode, they may be entered directly in get_path.m, or set
programmatically via set_path.m. Note that calls to set_path.m
re-write the get_path.m file, so they are durable in
response to clear calls. The path and data file specified in this
way are used by PSTess when dypar.batch_mode = true, as
specified in get_dypar.m. To turn batch mode off, simply set
dypar.batch_mode = false. When batch mode is turned off, the
application will prompt the user for information, as necessary.
Please see the analysis folder in this repository for two examples
based on a version of the Kundur 2-area system augmented with energy storage.
main_ess_example1.m-- Perturbs the real power command of the energy storage systems, as specified inmess_sig_example1.m.main_ess_example2.m-- Perturbs the reactive power command of the energy storage systems, as specified inmess_sig_example2.m.
Before running either of the examples, read the information in the
header of the main script. The instructions for main_ess_example1.m
are reprinted below for reference.
% Note: You must run this example from the 'analysis' folder. Before
% running, rename the original /pstess/mess_sig.m file to
% mess_sig_original.m. Then move mess_sig_example1.m into /pstess
% and rename it mess_sig.m. Make sure the working directory is
% configured in get_path.m. Before running double check that sw_con
% in d2asbegp_ess.m corresponds to ftype=6 (do nothing).
After running main_ess_example1.m, a small collection of figures
will be automatically generated and saved in the analysis/fig
directory. The figure on the left below shows the bus frequency
deviation vs. time in response to the input perturbation. The solid
blue trace shows the output of the full nonlinear simulation, and the
dashed magenta trace the output of the linearized simulation. The plot
on the right shows the same comparison but for the real power
modulation by the ESSs. The subscripts on the y-axis labels correspond
to the ESS index numbers. Both examples include the ESS-based
transient stability control strategy described in a recent
IET journal article.
| Bus frequency deviation | Real power modulation |
|---|---|
 |
 |
Where can I find documentation for PST and PSTess?
Please see the man folder under the top level of the repository. It
contains documentation for PST v3.0 and a supplemental document
describing the features of PSTess. For users without prior PST
experience, we strongly recommend reading both of these documents
before working with PSTess.
I think I found a bug, what should I do?
Please use the "Issues" feature of this repository. This helps others join the discussion and helps us keep track of and document issues. We will do what we can to address these issues; however, the PST base application has both known and unknown issues that users will encounter. Users of PSTess should be comfortable enough with MATLAB programming to address these issues on their own as they arise.
R. Elliott, D. Trudnowski, H. Choi, T. Nguyen, "The Power and Energy Storage Systems Toolbox – PSTess Version 1.0" September 2021, SAND2021-11259. Available: https://www.sandia.gov/ess-ssl/
J. Chow and K. Cheung, "A toolbox for power system dynamics and control engineering education and research," IEEE Trans. Power Syst., vol. 7, no. 4, pp. 1559–1564, 1992.
J. Chow, "Power System Toolbox Version 3.0 manual." Available: https://www.ecse.rpi.edu/~chowj/PSTMan.pdf
R. Elliott, A. Ellis, P. Pourbeik, J. Sanchez-Gasca, J. Senthil, and J. Weber, "Generic photovoltaic system models for WECC–A status report," in IEEE Power Energy Soc. Gen. Meeting, pp. 1–5, 2015.
R. T. Elliott, P. Arabshahi, and D. S. Kirschen, "Stabilizing transient disturbances with utility-scale inverter-based resources," IET Gen. Tran. Dist., vol. 14, pp. 6534–6544, Dec. 2020. Available: https://ietresearch.onlinelibrary.wiley.com/doi/
CAISO, "Inverter-based interconnection requirements (ER19-1153)." Available: https://www.caiso.com/Documents/
M. Klein, G. Rogers, and P. Kundur, "A fundamental study of inter-area oscillations in power systems," IEEE Trans. Power Syst., vol. 6, no. 3, pp. 914–921, 1991.
D. Trudnowski, D. Kosterev, and J. Undrill, "PDCI damping control analysis for the western North American power system," in IEEE Power Energy Soc. Gen. Meeting, pp. 1–5, 2013.