OpenDSS bindings based on the DSS C-API project
dss_python: Unofficial bindings for EPRI's OpenDSS
Python bindings and misc tools for using OpenDSS (EPRI Distribution System Simulator). Based on CFFI and
dss_capi, aiming for full COM compatibility on Windows and Linux.
If you are looking for the C API library, see
Version 0.9.8, based on OpenDSS revision 2246. This is a work-in-progress but it's deemed stable enough to be made public. Note that, while the interface with OpenDSS is stable (classic version), the OpenDSS-PM (actor-based parallel machine version) interface was integrated recently and is experimental.
This module mimics the COM structure (as exposed via
comtypes), effectively enabling multi-platform compatibility at Python level.
Most of the COM documentation can be used as-is, but instead of returning tuples or lists, this modules returns/accepts NumPy arrays for numeric data exchange.
This module depends on CFFI, NumPy and, optionally, SciPy.Sparse for reading the sparse system admittance matrix.
- 2018-08-10 / version 0.9.8: Reorganize modules (v7 and v8), adds 8 missing methods and new backend methods for OpenDSSDirect.py v0.3+. Integrates many fixes from DSS_CAPI and the upstream OpenDSS.
- 2018-04-30 / version 0.9.7: Fix some of the setters that used array data.
- 2018-04-05 / version 0.9.6: Adds missing
- 2018-03-07 / version 0.9.4: Allows using
lenon several classes, fixes DSSProperty, and includes COM helpstrings as docstrings. Contains changes up to OpenDSS revision 2152.
- 2018-02-16 / version 0.9.3: Integrates COM interface fixes from revision 2136 (
Nextiteration on some elements)
- 2018-02-12 / version 0.9.2: Experimental support for OpenDSS-PM (at the moment, a custom patch is provided for FreePascal support) and port COM interface fixes (OpenDSS revision 2134)
- 2018-02-08 / version 0.9.1: First public release (OpenDSS revision 2123)
Missing features and limitations
Most limitations are inherited from
Only the 64-bit version of OpenDSS is built. A 32-bit version should be possible with a few changes.
Currently not implemented:
DLL/ImplEvents.pas: seems too dependent on COM.
DLL/ImplDSSProgress.pas: would need a reimplementation depending on the target UI (GUI, text, headless, etc.)
Although tests were successful on openSuse 42.3 (both CPython 3.6 and PyPy3.5 v5.10.1).
Besides most of the COM methods, some of the unique DDLL methods are also exposed in adapted forms, namely the methods from
GetCompressedYMatrix (check the source files for more information).
Since no GUI components are used in the FreePascal DLL, we are experimenting with different ways of handling OpenDSS errors. Currently, the
DSS.Text.Command call checks for OpenDSS errors (through the
DSS.Error interface) and converts those to Python exceptions. Ideally every error should be converted to Python exceptions, but that could negatively impact performance. You can manually trigger an error check by calling the function
CheckForError() from the main module.
On Windows (Python 2.7, 3.6 and 3.7), you can install directly from pip:
pip install dss_python
If successful, you can then import the
dss module from your Python interpreter.
Get this repository:
git clone https://github.com/PMeira/dss_python.git
Assuming you successfully built or downloaded the
dss_capi (check its repository for instructions), keep the folder organization as follows:
dss_capi/ dss_python/ electricdss-src/
Open a command prompt in the
dss_python subfolder and run the build process:
python setup.py build python setup.py install
If you were using
win32com in code like:
import win32com.client dss_engine = win32com.client.Dispatch("OpenDSSEngine.DSS")
import comtypes.client dss_engine = comtypes.client.CreateObject("OpenDSSEngine.DSS")
you can replace that fragment with:
import dss dss.use_com_compat() dss_engine = dss.DSS
Assuming you have a DSS script named
master.dss, you should be able to run it as shown below:
import dss dss.use_com_compat() dss_engine = dss.DSS dss_engine.Text.Command = "compile c:/dss_files/master.dss" dss_engine.ActiveCircuit.Solution.Solve() voltages = dss_engine.ActiveCircuit.AllBusVolts for i in range(len(voltages) // 2): print('node %d: %f + j%f' % (i, voltages[2*i], voltages[2*i + 1]))
If you do not need the mixed-cased handling, you can omit the call to
use_com_compat() and use the casing used in this project.
If you want to play with the experimental OpenDSS-PM interface, it is installed side-by-side and you can import it as:
import dss.pm dss.pm.use_com_compat() dss_engine = dss.pm.DSS
Since the DLL is built using FreePascal, which is not officially supported by EPRI, the results are validated running sample networks provided in the official OpenDSS distribution. The only modifications are done directly by the script, removing interactive features and some minor other minor issues.
The validation scripts is
tests/validation.py and requires the same folder structure as the building process. You need
win32com to run it.
Currently, the following sample files from the official OpenDSS repository are used:
Distrib/EPRITestCircuits/ckt5/Master_ckt5.dss Distrib/EPRITestCircuits/ckt7/Master_ckt7.dss Distrib/EPRITestCircuits/ckt24/Master_ckt24.dss Distrib/IEEETestCases/8500-Node/Master-unbal.dss Distrib/IEEETestCases/IEEE 30 Bus/Master.dss Distrib/IEEETestCases/NEVTestCase/NEVMASTER.DSS Distrib/IEEETestCases/37Bus/ieee37.dss Distrib/IEEETestCases/4Bus-DY-Bal/4Bus-DY-Bal.DSS Distrib/IEEETestCases/4Bus-GrdYD-Bal/4Bus-GrdYD-Bal.DSS Distrib/IEEETestCases/4Bus-OYOD-Bal/4Bus-OYOD-Bal.DSS Distrib/IEEETestCases/4Bus-OYOD-UnBal/4Bus-OYOD-UnBal.DSS Distrib/IEEETestCases/4Bus-YD-Bal/4Bus-YD-Bal.DSS Distrib/IEEETestCases/4Bus-YY-Bal/4Bus-YY-Bal.DSS Distrib/IEEETestCases/123Bus/IEEE123Master.dss Distrib/IEEETestCases/123Bus/SolarRamp.DSS Distrib/IEEETestCases/13Bus/IEEE13Nodeckt.dss Test/IEEE13_LineSpacing.dss Test/IEEE13_LineGeometry.dss Test/IEEE13_LineAndCableSpacing.dss Test/IEEE13_Assets.dss Test/CableParameters.dss Test/Cable_constants.DSS Test/BundleDemo.DSS Test/IEEE13_SpacingGeometry.dss Test/TextTsCable750MCM.dss Test/TestDDRegulator.dss Test/XYCurvetest.dss Test/PVSystemTestHarm.dss Test/TestAuto.dss Test/Stevenson.dss Test/YgD-Test.dss Test/Master_TestCapInterface.DSS Test/LoadTest.DSS Test/IEEELineGeometry.dss Test/ODRegTest.dss Test/MultiCircuitTest.DSS Test/TriplexLineCodeCalc.DSS Test/PVSystemTest-Duty.dss Test/PVSystemTest.dss Test/REACTORTest.DSS
On Windows 10, remember to set the compatibility layer to Windows 7 (set the environment variable
__COMPAT_LAYER=WIN7RTM), otherwise you may encounter issues with COM due to ASLR on Python 3.6.
There is no validation on Linux yet, since we cannnot run the COM module there. The most likely solution will be to pickle the data on Windows and load them on Linux.
Besides bug fixes, the main funcionality of this library is mostly done. Notable desirable features that may be implemented are:
- More and better documentation
- Create wheels for Linux distributions, maybe using the Anaconda stack.
- Create a more "Pythonic" API. This would break compatibility with COM, but may result in a more pleasant environment for using OpenDSS in Python.
If you have any question, feel free to open a ticket on Github or contact me through Twitter. Please allow me a few days to respond.
Credits / Acknowlegement
dss_python is based on EPRI's OpenDSS via the
dss_capi project, check its licensing information.
This project is licensed under the (new) BSD, available in the
LICENSE file. It's the same license OpenDSS uses (
I thank my colleagues at the University of Campinas, Brazil, for providing feedback and helping me test this module.
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