An improved fault phase classification and location estimation technique for EHV transmission line with fsc based on fuzzy logic featuring capacitor voltage drop

Abstract

Protection of series compensated line is a challenging task due to non linearity involved in presence of series capacitance. The novelty of this research paper is the application of capacitor voltage drop signals of fixed series capacitors (FSC) over one cycle after occurrence of fault for faulted phase classification and to the fuzzy system for fault distance estimation in a 400 kV transmission line with FSC. Such application of capacitor voltage drop signals has never been implemented in any fault analysis schemes which makes this technique novel. Feasibility and reliability of the proposed technique has been tested for all ten types of shunt faults on power system model at different fault inception angles (FIA), realistic fault resistances over a range of fault locations. The proposed fuzzy logic based technique has less computation complexity. Real transmission system parameters of 400 kV Wardha - Aurangabad transmission line, India (400 km) with 40% compensation at one end are implemented for this research. Percent absolute error is calculated for performance evaluation of the proposed method. Large numbers of test cases are generated which provide complete distance protection scheme giving quite accurate results with percent absolute errors mostly within 2.75% demonstrating more accuracy as compared to previous fuzzy based fault location schemes, least complexity and robustness of the proposed technique.