Fault detection and classification for TCSC compensated transmission lines using wavelet energy

The installation of Thyristor Controlled Series Capacitor (TCSC) in a transmission line affects both steady-state and transient components of the current and voltage signals. As a result the traditional algorithms based on steady-state components find difficulty in accomplishing fast and reliable detection and classification of faults in such lines. This paper presents a fast and reliable fault detection and classification technique for a TCSC compensated line by employing the effective time-frequency analysis based on discrete wavelet transform (DWT) on the measured three-phase current signals. In this work, the features (detail coefficients of level-1, cD1) of currents signals are extracted by DWT using `db4' mother wavelet. The fault detection and classification task is accomplished using the spectral energy (SE) of cD1. The extraction of the new efficient feature; the spectral energy of cD1 is the main contribution of the proposed work. The performance of the proposed fault detection and classification scheme is tested for a wide variety of fault scenarios by generating data on a 400 kV double circuit TCSC compensated transmission line through EMTDC/PSCAD software. The results clearly show that using the proposed method fast and reliable detection and classification of faults on TCSC compensated transmission lines can be accomplished.