OpenDSS / News: Recent posts

EPRI is planning another 4-day virtual training course this year. See the attachment for more information and registration link.

With several new users since the global training in August, it is useful to review the OpenDSS voltage base rules since they are different than many other programs:

• Voltage bases are not used for the solution of the network; the per-unit system is not used internally. The solution is performed in actual volts, amps, and ohms (or siemens) .
• There must be sufficient data provided for each circuit element of the system model to formulate the model of the element in actual impedance values. So the kV value is used as a base to convert input values in pu, percent, or power to ohms.
• Since most power engineers refer to ratings of 3-phase system elements as L-L kV, OpenDSS uses L-L kV for the ratings of 3-phase elements.
• We extended that rule to include elements that are declared as 2-phase, since in the US, most 2-phase systems are 2 phases of a 3-phase system with the voltages related by sqrt(3) and displaced 120 degrees from each other. (You can do that if you have a neutral conductor).
• The kV rating of 1-phase devices is the value that appears across the two wires of each terminal at 100% rated voltage. This would apply to all Power Conversion (PC) elements and Transformer elements. Note that 1-phase LINE elements have only one conductor per terminal; LINE elements are defined in ohms and do not have a voltage base. They can be connected anywhere in the circuit without concern for matching voltage bases. (In this regard, OpenDSS is formulated more like an EMT program than the usual power flow.)
• OpenDSS can model high phase order systems (e.g., 6-phase). The kV value is generally L-L rating for these systems. However, I would recommend running a small test with a few elements that you can verify the solution by inspection to see if OpenDSS interepreted the model correctly. (We have tested both 6-phase and 12-phase models.)

Some users have noticed the paper on an open-source Python-based power flow tool called "pandapower" published in the IEEE Transactions on Power Systems November 2018 issue. Some comments were made in the paper about OpenDSS that mischaracterize the program and that has raised some concern among the users. Using the comparisons in the IEEE paper, it is time to revisit some of the unique features of OpenDSS for newer users.... read more

A frequent contributor to this forum, Celso Rocha, has graciously allowed us to post his undergrad project to the examples. It has the DSS and Python files along with his report. It should be a great help to users and we thank him. You can find it at

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Examples/Celso_Example

Here is the link:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/OpenDSSPrimer_Portuguese.pdf

Thanks to Paulo and Celso

Huijuan Li has recently translated Jason Sexauer's Primer for OpenDSS into both Traditional and Simplified Chinese. You can find these documents here:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/OpenDSSPrimer_SimplifiedChinese.pdf

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/OpenDSSPrimer_TranditionalChinese.pdf

Excel VBA is very good at prompting you for the OpenDSS COM interface properties and methods. But if you are working in Python or MATLAB you may find it difficult to remember or figure out the property names. Andrea Ballanti has put together a very nice TechNote on ways to see the list of properties in these languages as well:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/Technote_COM_PropertyListVisualization.pdf

We've just posted a technote by Andrea Ballanti on how to model two types of underground cable in OpenDSS. Many users should find this useful as these models are not explained in the user's manual:
https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/TechNote%20CableModelling.pdf

There is a vibrant OpenDSS user community in Brazil. Paulo Radatz, a student at the University of Sao Paulo, wrote a nice report for his undergraduate project and has contributed the DSS files from his project as a good example of how to use the program.

The report is in Portuguese, but is still understandable if you know the language of mathematics and OpenDSS script.

You can find everything at:... read more

In the files download area. 7.6.4.70 is still there for the moment.

Davis Montenegro has done some investigation of how to do early binding to the COM interface in various languages and posted a description in the Help forum:

http://sourceforge.net/p/electricdss/discussion/861977/thread/b320652e/

There is also a report of his study results attached to the posting as well as in the Doc Folder:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/COM%20Speed%20Comparison.pdf... read more

Several new Export commands. Also, some new properties in the COM interface as well as cumulative additions and bug fixes since 7.6.4.36,

You can get it from the main download site for OpenDSS.

Until we can get the Mediawiki back up and working, I've posted PDFs of many of the pages here:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/Questions

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/TechNotes

These documents contain many useful materials and I recommend all users download these and read them.

See the announcement on the Open Discussion Forum or visit Xendee.Com.

The variable facility (@var) in OpenDSS has been enhanced. You can now use variables to define element names and bus connections.

This allows you to define a generic description of an subnetwork that might be used repeatedly and use the var facility to set the actual values. As an example, see:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Examples/Scripts/ZigZagTransformerWithVar.DSS... read more

This beta includes an updated LOAD model for harmonics analysis that is described in the following document:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/Harmonics%20Load%20Modeling.pdf

Of course, the Beta versions may be found in these folders:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/x64
https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/x86

An installer for version 7.6.4 build 36 has been posted on sourceforge.net in the usual place:

http://sourceforge.net/projects/electricdss/files/

This version has several updates and bug fixes:

Var Command/ Named Variables in Scripting

This version introduces named variables in OpenDSS script. This enables scripts like the one below that uses named variables (beginning with the ‘@’ character) to define text strings to be used in the scripts. The ‘var’ command was introduced to define and display variable values:... read more

I just posted a new beta build of 7.6.4 version. You can find it at the usual place:

http://svn.code.sf.net/p/electricdss/code/trunk/Distrib/x86/
http://svn.code.sf.net/p/electricdss/code/trunk/Distrib/x64/

Please report any issues found.

There a couple of significant changes that warranted increment the release version from 7.6.3 to 7.6.4. The build number remains sequential so it is easier to see where issues may have cropped up.... read more

The Magic Carpet Ride video of a cloud passing over a distribution feeder with rooftop solar PV generation has been posted onto this site. You can find a link to it here:

https://sourceforge.net/p/electricdss/discussion/861976/thread/ddf244d9/#9e81

Note that this is a 20 MB download.

Installer for 7.6.3 build 31. Various minor bug fixes and enhancements. Most are discussed in the Discussion Forum. Search for recent references where users were instructed to get the latest beta.

Still looking for a suitable host for the Mediawiki site.

The MediaWiki site on SourceForge.net that supported the Type Library Documentation has been retired as of 6/19/2014. Unfortunately, we didn't know it was being retired until after the fact and are now actively investigating other means of posting the material that was once on the OpenDSS Wiki.

Roger Dugan 6/24/2014

See the PDF for the COM interface documentation:

https://sourceforge.net/p/electricdss/code/HEAD/tree/trunk/Distrib/Doc/OpenDSSComDoc.pdf... read more

We have created a page in the Wiki that lists the entire type library with enums, interface definitions, with properties and methods. You can find the documentation here:

http://sourceforge.net/apps/mediawiki/electricdss/index.php?title=Type_Library_Documentation_Listing

Latest beta builds Posted here:

http://svn.code.sf.net/p/electricdss/code/trunk/Distrib/x86/
http://svn.code.sf.net/p/electricdss/code/trunk/Distrib/x64/

See post in Open Discussion:

http://sourceforge.net/p/electricdss/discussion/861976/thread/b9c09f15/

See Wes Sunderman's post in the Experts thread:

http://sourceforge.net/p/electricdss/discussion/experts/thread/117df545/

At Version 7.6.3.27 we added an interface to the internal OpenDSS Parser.

Check out the documentation in the Wiki:

http://sourceforge.net/apps/mediawiki/electricdss/index.php?title=TechNote_Parser_Interface