User Success and Feedback

User Success Story (6/8/2007)

I have been in the last few days using InterPSS to assist in some real tasks and getting very good results. With the functions in CML being quite easy and behaving in a predictable way now - I think your project is ready for some big time action.


A generating company experienced a trip of a 500MVA combined cycle plant that was unexpected and was difficult to explain. The unit was running at a medium load and importing quite a large amount of VArs when an unrelated large generating station tripped elsewhere in the network. The resulting underfrequency event caused the combined cycle plant to trip by loss of excitation protection - even though the Voltage Regulating system has a load angle limiter, it appeared as if the limiter did not function correctly.This unit tripping in cascade was highly undesireable and caused the event to be significantly more severe than the available reserve capacity in the network at the time. All standard tests of the limiter, excitation system and protection devices could not explain why the unit tripped and each device appeared to function correctly.

Using InterPSS to simulate the network event, with a detailed model of the combined cycle plant and its controllers (modeled with scripting and CML) allowed the investigating engineers to identify that the trip was related to an interaction between the load angle limiter and Power System Stabiliser. The PSS uses frequency as an input and during this event was over-riding the load angle limiter enough to drive the unit beyond the Loss of Excitation protection pickup.

Once the problem was identified with simulations in InterPSS, it became possible to formulate a solution to prevent a re-occurance of such an event in the future. The Limiter output could be modified in such a way that the PSS action could be dynamically prevented from driving the field beyond the machine capability limits during even extreme frequency excursions, yet still provide an adequate level of damping for the machine. The theoretical solution was implemented in InterPSS and indicated it would be successful under a wide variety of conditions and network contingencies.

The plant hardware was then modified and its behaviour verified against the predictions made with interPSS. Very good agreement between the computer simulated predictions and actual machine behaviour was verified and this gave the investigating engineers the confidence that the fault had been identified and rectified.

It was arranged with the network operator to verify the ride through capability of the machine by staging a large, system-wide drop load test to replicate the original disturbance where the plant had failed to ride through. Using InterPSS it was possible to convince the network operator of how much reserve capacity would be needed should the combined cycle plant fail the test, as well as predicting the expected results. The system test was performed and verified the plant was now able to ride through the event - just as InterPSS had predicted.

(The person, who sent the story, at the time was working for ABB Australia)

User Feedback

10/22/07 - Grid Computing solution Setup at Shanghai Jiaotong University

InterPSS Grid Computing solution has been successfully setup at Shanghai Jiaotong University, Shanghai, China. The following is a message we received from them.

根据GridGain和InterPSS的在线帮 助,在本机上可以顺利安装运行InterPSS。GridGain相对 Globus而言虽功能简单,但是确实比较便捷实用。周博士的程序人机交互界面十分友好,关于Loadflow的算例很有意思。随信附上关于 GridGain网格中间件下InterPSS的安装注意事项,仅供参考。






Dear Dr. Zhou.

Thank you.

I have enjoyed working with InterPSS program this entire week. It is a beautiful simple OOP.

The email you sent to Power-Globe members was forwarded to me from one of my good friends. He sent me a great present. I downloaded it and test the InterPSS load flow part and it is working really fine. It is quite simple and direct for a Power Engineer. Beautiful. !!!!!

At the beginning I had some problems because I am running it in a Windows Vista machine. I did not find any online help about Installation problems, then it took me a little more time to find out the way the program is installed.

Thanks again

Ramiro Rodas

Datfax Services Corp.


"Your team obviously has some very advanced ideas about how to apply some incredibly powerful software engineering ideas to an area of software development in which the dominant firms continue to sell old-fashioned, badly-designed and very-expensive tools to engineers who don't realize how badly they are being screwed."


First, let me congratulate you for the job that you and the people behind InterPSS is doing. I think this is really a nice move forward in terms of software development for power systems and I hope you will continue advancing InterPSS. I see three big advantages in InterPSS for academic use:

    • It is free and very easy to install, so students can have easy access to their own copy.
    • It offers basic features for the modelling and simulation of the elements and power system. This makes easier to use it for students who are just starting to understand power systems analysis. Some other programs offer a lot of features and possibilities to simulate an element that confuse a person without to much experience in the area.
    • It is the first time I see a simple to use program that includes the three main type of studies that we usually teach at the undergrad level: power flow, short circuit analysis and stability.

Dr. Fernando Castellanos

Department of Electrical and Computer Engineering The University of The West Indies - Trinidad and Tobago