Keywords: object-oriented physical system modeling, power system modeling, power system simulation, power system analysis, graphical user interfaceThe increase in size and complexity of interconnected electric power systems, coupled with the industrial commitment to maximize security at a minimum cost, has led to the development of many special software packages for power system analysis. These tools are used by power system operators and system planning engineers to ensure that the electric power system is able to operate without instability under a wide range of system conditions. This paper presents a new development of an integrated power system analysis package named MidFielder, which is now integrated with a recent technology using object-oriented physical system modeling language for very flexible studies in power systems. To authors' knowledge, it is the first attempt to include this technology into the power system analysis package.We have feedback from users both in industrial and academic sectors that not only should the simulation packages provide computational efficiency, user-friendly environment, but also should have the flexibility and ability of easy modeling. This is very important for a rapid way for research and development in power systems. Many commercial power system analysis packages available on the market provide the possibility to model controllers such as governors and exciters, but do not allow the user to simulate generic models of generators or networks. Therefore, it is cumbersome for research purposes. On the other hand, if this problem can be solved, power system analysis package will have the completeness for industrial, educational and research purposes.Recently, development within the field of object-oriented physical system modeling is a fast-growing area of modeling and simulation that provides a computer-supported way of doing mathematical and equation-based modeling. Modelica is the object-oriented simulation language being developed to advance the state of system simulation technology. This technology has revolutionized the way in which the model can be constructed similar to the physical system; therefore, a straightforward modeling is enabled. The motivation for introducing Modelica in Tokyo Electric Power Company (TEPCO) project is to remove some of the necessary skills in computer programming and numerical analysis, so that power system engineers are able to focus on describing the model instead of the actual lowlevel implementation. The development of power system models of appropriate fidelity is a key aspect of power system simulation processes. The models must allow all relevant multi-disciplinary modeling criteria, e.g. model structure and data handling, to be computed efficiently, easily, and with sufficient accuracy. Recently, the project team at TEPCO is attempting to create an interface system of an integrated power system analysis package with a software tool using object-oriented physical modeling language Modelica to aid the power system engineers in the ...
