The Research Of Visual Calculation Software Of Power System Based On GIS Control

Power flow and short circuit current calculation are the important facilities in the power system analysis. There are the basis of relay protection setting and security analysis of power system. With the development of electrical power enterprise and computer technology, it is important to develop a highly efficient, better maintainable and human graphic interface based software package for power system analysis and computing. Traditional calculating software of power system lacks human user interface. It takes user much time to input networks original data and is easy to make mistakes although its powerful calculation function. Basing on the analysis of traditional power system calculation software, this paper introduces a visual calculating software, which includes power flow and short circuit calculation. The idea on design and implementation, the structure and the function of software are presented in this paper. The implementation of graphic user interface of software and the improvement of algorithm as the pivot of the thesis are also introduced here. Finally the system which is composed of graph editing and network topology, power flow and short circuit calculation and data management is proved to be reliable and practicable by a 22-node example. (1) Graph editing and network topology: The thesis introduces a new handy design method of programming. It adopts Delphi7.0 as a programming tool and installs GIS (Geographic Informational System ) control—MapObjects to develop the graph edit on the basis of good editing function of MapObjects. The software adequately uses the idea of object-oriented programming and introduces the concept of graphic unit synchronously and sets up Equipment--graphic unit--the interrelation between class by the method of class's inheritance, polymorphism and virtual function, which make it easy to expand, maintain and replant. In the network topology part, basing on the analysis of method of traditional network topology, the thesis presents a versatile and easily expandable power network topology method using node amalgamation technology on the abstract electrical power network model, which can automatically and quickly generate topology on the GIS platform. (2) Power flow and short circuit current calculation: After the analysis of the algorithm of traditional power flow calculation, the thesis uses Newton's method, which has better reliability then others. The calculation speed is greatly accelerated by improving the access technique of its sparse matrix using two-dimensional chain table data structure. Traditional short calculation software ignores the affect of Symmetrical component phase after transformer, which affects the accuracy of result to some extent. This software takes the symmetrical component phase after transformer into account to further improve the accuracy of result. (3) Data management: The software manages the electrical power network graph, equipment parameter and calculating results by Paradox database. The information deposited in the database can be inquired, showed and printed expediently. The system is verified to be steady in operation and rigorous in results by a typical example.