A rigid approach of generalized power flow analysis for distribution systems

The novel approach developed in this paper is for the accurate determination of power flow in both normal and faulted unbalanced distribution systems. Based on a hybrid compensation method, the proposed methodology has three distinguishable enhancements compared with the existing algorithms. First, the internal impedance of power source is discussed in detail, and a revised power flow algorithm is introduced accordingly. Second, various types of single or multiple faults are simulated in a complete uniform model without any extra processing for a certain fault. At the same time, both direct short circuits and faults through impedance are under full considerations. Third, a novel Thevenin equivalent is developed when the source transformer is ungrounded. In addition, the influence of shunt capacitance of lines is studied, which is especially important for single line-to-ground faults in an ungrounded system. A computer program has been developed based on this methodology. Numerical tests on a Chinese large real distribution system verify the validity and efficiency of the presented algorithm