Decision tree‐induced fuzzy rule‐based differential relaying for transmission line including unified power flow controller and wind‐farms

The paper presents a decision tree (DT) induced fuzzy rule‐based intelligent differential relaying scheme for transmission lines including unified power flow controller (UPFC) and wind‐farms. The conventional distance relaying scheme fails miserably in protecting transmission lines including flexible AC transmission systems controllers such as UPFC and further, the protection issues become more challenging when wind‐farm is integrated. The proposed protection scheme extracts features from the instantaneous voltage and current signals from both ends of the transmission line using discrete Fourier transform based pre‐processor and computes corresponding differential features. The differential features are used to build the fault classification tree using a data‐mining algorithm known as DT. Further, the fuzzy membership functions are drawn using the DT thresholds and the corresponding fuzzy rule‐base is developed for final relaying decision. The proposed technique has been extensively tested (in MATLAB environment) for single circuit and double circuit transmission lines including UPFC and wind‐farms with wide variations in operating conditions. The test results indicate that the proposed DT‐induced fuzzy rule‐based relaying scheme is highly reliable and robust for protection of complex transmission line including UPFC and wind‐farm.