Common Issues

This section will describes some (maybe) common issues and their solutions. If you encounter and solve an issue, please file a GitHub issue so that we can add your problem and solution to this section.

Before diving too deeply into the issues listed here, first ensure that you have all the prerequisite software installed (including PowerWorld Simulator and the SimAuto add-on) and are using a supported version of Python (>= 3.5).

Installation/Virtual Environment Issues

If you have issues installing ESA and/or its dependencies, you may need to do some manual work installing prerequisites in your virtual environment. Hopefully following these simple directions will help fix most issues.

  1. Start fresh! Completely remove your virtual environment and recreate it. PyCharm makes this pretty easy, or you can do so manually using Python’s guide. The remaining directions will assume you’re typing commands into your activated virtual envrionment.

  2. Reinstall pip and setuptools: python -m pip install --upgrade --force-reinstall pip setuptools. We’re intentionally using python -m pip instead of just pip to avoid possible path issues. Note that you might need to run this command twice (the first may fail for some unknown reason).

  3. Check out ESA’s setup.py file and look for install_requires. It’ll look something like ['pandas', 'numpy', 'pywin32', 'pypiwin32'].

  4. Using what we found under install_requires, install ESA’s dependencies manually. To avoid compiler dependencies, we’ll get binary distributions only: python -m pip install --upgrade --only-binary :all: pandas numpy pywin32 pypiwin32

    • If this command fails, you may need to pick and choose which dependencies you grab binary distributions for, and which you get other types of distributions for. Here’s the Python documentation. As a strictly illustrative example, if we only want to get binary distributions for pandas and numpy, we’d modify the previous command to instead read like so: python -m pip install --upgrade --only-binary pandas,numpy pandas numpy pywin32 pypiwin32

    • The authors of ESA have at times had issues installing pywin32 and pypiwin32 when not using the --only-binary option. So, if you’re encountering errors you suspect are related to pywin32, try to uninstall and reinstall pywin32 and pypiwin32 with the --only-binary option.

  5. After you’ve installed ESA’s dependencies, it’s time to install ESA: python -m pip install esa

PyCharm Virtual Environments

If you use PyCharm to automatically create virtual environments for you, there’s a little extra work to do to get everything working for Python 3.8 (and possibly for other Python versions as well). Start up a terminal inside PyCharm (click on the Terminal button which defaults to the lower left area). In the terminal, run: python -m pip install -U --force-reinstall pip. Note you may need to run this command twice - mine failed the first time. The same may be required for setuptools and/or distutils.

Errors/Issues Initializing a SAW Instance

This section will cover some common issues when attempting to initialize a SAW instance. The first thing to check is that your arguments are correct - check the API documentation first.

esa.saw.PowerWorldError: OpenCase: Errors have occurred

You may see an error stack trace that looks something like the following:

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "C:\Users\myuser\git\ESA\esa\saw.py", line 111, in __init__
    self.OpenCase(FileName=FileName)
  File "C:\Users\myuser\git\ESA\esa\saw.py", line 680, in OpenCase
    return self._call_simauto('OpenCase', self.pwb_file_path)
  File "C:\Users\myuser\git\ESA\esa\saw.py", line 1101, in _call_simauto
    raise PowerWorldError(output[0])
esa.saw.PowerWorldError: OpenCase: Errors have occurred

Often, this is due to a bad path specification. Ensure you’re providing a full file path, including the file extension (.pwb), and that the file exists at the exact path you specified.

Also, make sure that the file is actually a PowerWorld binary file. If you open the file with a text editor and see a bunch of weird symbols that are unintelligible to a mere mortal, it’s likely a PowerWorld binary file. If, upon opening the file you see something like:

version https://git-lfs.github.com/spec/v1
oid sha256:f05131d24da96daa6a6712c5b9d368c81eeaea5dc7d0b6c7bec7d03ccf021b4a
size 34

Then you’re looking at a Git LFS pointer file, and likely need to install Git LFS and perform a git lfs pull.

TypeError: This COM object can not automate the makepy process - please run makepy manually for this object

If you see an error like the above, try initializing your SAW object again but set early_bind=False. While we’re unsure of the root cause of this issue, it seems to be related to the fact that early_bind=True preemptively creates some Python files related to the SimAuto COM API, and file permission issues can crop up.

AttributeError: module ‘win32com.gen_py.C99F1760-277E-11D5-A106-00C04F469176x0x20x0’ has no attribute ‘CLSIDToClassMap’

If you see an error like that listed above, it’s possible the pywin32 cache has been somehow corrupted (perhaps your computer crashed while a script which uses ESA was running). Simply delete the following directory (the default, you may have to adapt for your system):

C:\Users\<your user directory>\AppData\Local\Temp\gen_py

The key part here is gen_py. If the above path isn’t right for you, use Windows to search for gen_py.

ModuleNotFoundError: no module pywintypes

If you see an error like that listed above, try reinstalling pywin32 and pypiwin32 with the --only-binary option, as described in the Installation/Virtual Environment Issues section.

esa.saw.PowerWorldError: Access Violation

If you see an error like that listed above, you probably could observe the same errors using script functionality in the PowerWorld Simulator interface. When you start the simulator (either the GUI or ESA) in a remote desktop environment, due to security reasons the system may block the simulator to save or create any files. As a result, any functions that require the simulator to generate files will fail with such errors. There are not much things we could do from our side, but one possible hack is to login locally and use the simulator first, then use the remote desktop to continue your work.