Short circuit analysis in the phase domain for distribution networks

Short circuit calculations in distribution systems are performed using the traditional method of symmetrical components. However, this representation losses accuracy when the system is intrinsically unbalanced, as it is recognized for the case of distribution systems. This paper describes a methodology - implemented in MATLAB - that makes possible the analysis of short circuit for distribution networks without the use of symmetrical components. The elements in the distribution system are represented in the "phase domain" by their corresponding three phase impedance matrices. These element-matrices are used to construct two topologically based matrices that represent the entire network. General relationships between different types of fault and these network matrices are presented allowing the calculation of short circuit in the phase domain. The proposed method has shown to be very fast and robust. It has been tested using modified IEEE benchmark distribution systems and compared against commercial products using symmetrical components.