Power Systems Fault Type Identification Based on Park´s Transformation Algorithm

Fault identification is necessary for system protection and the selection of suitable relays, which are required for the subsequent fault isolation. In this paper, fault identification is achieved using a simple and numerically efficient algorithm based on Park´s transformations. The algorithm uses two transformation matrices. The first matrix is used to filter out the dc offset and harmonics that contaminate the three-phase voltage signal. The second transformation is used to estimate the positive and negative sequence components. The zero sequence components are estimated from the first transformation matrix. Results based on detailed system models are presented in the paper. Having identified the positive sequence, negative sequence and zero sequence components, the fault type can easily be identified