The Extension Approach For Load Model Of Object-Oriented Power System Transient Stability Simulation Software

The mathematical models are the base of power system simulation and analysis. But all power systems simulation software don't need to include all elements model, and they are not able to do this too. As a result, such software as PSASP, PSS/E and so on provide custom extension environment for elements modeling. Using the object-oriented extension methods, this paper implements the custom extension of the composite load model based on InterPSS, and does some certifications.Firstly, this paper analyzes the extensibility requirement of power systems simulation software, represents the design method and the characteristic of process-oriented program, more than this, it introduces the extension methods including UDM and UPI in PSASP, which is a commercial power systems simulation software and used universally, and their development process, feasibility and limitation are presented in details.Secondly, this paper represents the design method and the characteristic of object-oriented program, introduces a new type power systems simulation software InterPSS, which bases on internet and object-oriented technology. And it represents the design idea, system architecture, flexible extensibility and extensible methods of InterPSS minutely.This paper analyzes the particular implement process of the composite load model extension in InterPSS Scripting environment for transient stability simulation, more than this, it gives the Java program of the composite load model for custom extension. And then the custom extension is proved to be right through a transient stability simulation case, which is a 5 buses system including 2 generators. Under the same transient stability calculation situation, the simulation results are compared systematically between InterPSS and PSASP. The comparisons demonstrate that the the simulations in InterPSS is credible, it can be used as a powerful tool for power systems planning, design and the decision of operation scheduling.The custom extension program of the composite load model is encapsulated as plug-in by using InterPSS Scripting packaging method. So far the plug-in is part of InterPSS now, it can be selected in InterPSS GUI and used for transient stability simulation case to simulate the dynamic characteristic of load, and the custom extension is complete and successful now. In the end, after the custom extension implementation of load and the comparisons of simulation results, the paper represents and generalizes the characteristics and performance of InterPSS. Based on its open-source architecture and object-oriented technology, InterPSS is able to provide a friendly and flexible custom extension environment,and it is a quite promising power systems simulation software.