Silence!

PSSE prints a voluminous amount of information to the command line when you are running a program. Do you remember seeing this when you start PSSE up?

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PSS«E Version 32
Copyright (c) 1976-2012
Siemens Energy, Inc.,
Power Technologies International (PTI)
This program is a confidential unpublished work created and first
licensed in 1976. It is a trade secret which is the property of PTI

We will show you a little function that you can use to selectively turn off this output (and other PSSE output) or redirect it to a log file.

This blog post is in response to a question by chip on the python for power systems engineers forum. Chip wanted to ignore some of the output that PSSE was printing without ignoring all of the program’s output.

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from __future__ import with_statement
from contextlib import contextmanager
import sys
import os

@contextmanager
def silence(file_object=None):
    """
    Discard stdout (i.e. write to null device) or
    optionally write to given file-like object.
    """
    if file_object is None:
        file_object = open(os.devnull, 'w')

    old_stdout = sys.stdout
    try:
        sys.stdout = file_object
        yield
    finally:
        sys.stdout = old_stdout

The function silence can be used to selectively turn off PSSE output printing in your program. Use it like this:

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with silence():
  psspy.psseinit(10000)

Printing from within the context block (the with statement) will be ignored. (Note that we have initialised PSSE with buses set to ten thousand – based on our research of the optimal bus number).

What if you must redirect the PSSE output to a file? Got you covered. Use the silence function like this:

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psse_log = open('psse_logfile.log', 'w')
with silence(psse_log):
  psspy.psseinit(10000)

There are more juicy details about how the context manager works on the forum: Silencing PSSE Stdout

edit: You must also redirect PSSE output to Python using the redirect module included with every PSSE installation:

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import redirect
redirect.psse2py()

psse_log = open('psse_logfile.log', 'w')
with silence(psse_log):
  psspy.psseinit(10000)