In any project, doing a simple short circuit verification and load flow analysis will save the electrical engineer headaches during testing, commissioning and system reliability testing of the project.
I know some electrical engineers who don't even bother doing a manual calculation because they assume that what they have experienced in their past projects will be the same as their current. This is totally wrong. Every project, despite having similarities have different electrical parameters. Making assumptions and not verifying it mathematically is totally unacceptable.
One reasoning for this may be, I can't do manual calculation, the project is too complex or I don't have the tools to do system analysis, etc. Again, these are just alibis for not doing what is a very important aspect in electrical design.
I have now tried using InterPSS. My first impression,it is very versatile and simple. When I have seen the icons, I ask myself, where are the utility, transformer, feeder, motor icons, etc. But as I started using it, I came to know that the few icons appearing in the tool bar can simlulate several equipment.
The results are actually comparable to ETAP. If you have started using this power system analysis software, you may not even bother looking at the very expensive commercial softwares again.
The only limitation I found is that the IEC Standard short circuit calculation is not yet available. Using the generic one will suffice however. I have not tried using motor starting analysis but I knew that it will be probably as easy as changing the values of the motors with their starting parameter values. This is just a personal opinion though. I have not actually done it. I will share it once I get the right answer.
Screen captures and some explanation of a simple calculation that I made using the InterPSS could be found at the download section.
Some higlights of the calculation are:
33KV, X/R = 7, MVAsc = 2000