A comprehensive protection scheme for micro-grid using fuzzy rule base approach

Abstract

The paper presents a comprehensive primary and backup protection scheme for micro-grid using fuzzy rule base approach. The proposed scheme starts with pre-processing of the retrieved current and voltage signals at both ends of the faulted feeder and adjacent feeder to compute the differential features. The differential features are used to build two separate decision trees (DTs) for the primary and backup protection. The differential features between immediate buses of faulted feeder are considered for primary protection and differential features between far end buses of faulted and adjacent feeders are used to build decision tree for secondary protection. From the developed decision tree classification boundaries, the fuzzy membership functions are generated and the corresponding fuzzy rule base is formulated for final relaying decision. The proposed scheme is tested for numbers of fault and no fault events simulated in the studied micro-grid with wide variations in system parameters and fault parameters in different operating mode. The extensive test results show the efficacy of the proposed protection scheme to provide a reliable protection measure to both primary and backup protection of micro-grid.