Object Oriented Design of a Transient Analysis Program

This paper presents a design methodology of an electromagnetic transient analysis program based on an objectoriented approach. Two important features of the object oriented programming are (i) abstraction of data and their procedures using classes and (ii) derivation of a new class from an existing class using the concept of inheritance. In the proposed design methodology, first the base class, from which all kinds of circuit components are derived using inheritance, is defined. When a specific circuit component is derived from the base class, the parameters, the internal variables, and the behavior of the component are defined and described in the code defining the derived class. This means that each circuit component manages its data and knows how to initialize and update itself, that is, the circuit solver does not have to manage and know them. In this way, we can separately write the code of the circuit solver and that of circuit components, and thus, coding is simplified and code maintainability is enhanced. Especially, adding a new component does not require modifications in the circuit solver code. Using the proposed approach, a new transient analysis program named “XTAP” (eXpandable Transient Analysis Program) has been created. Some practical implementation issues are also presented in the paper.