Bi-orthogonal Wavelet Function-Based Transmission Line Protection to Improve Grid Reliability

Transmission line protection becomes more complicated because of grid complexity and variability in system parameters. Due to huge coverage of transmission lines in the power system, the fault may be bound to occur with various causes. Recently due to the involvement of distribution generation (DG) in transmission lines, network complexity has vitally increased. This paper presents a protection algorithm for three-phase transmission lines utilizing wavelet transform (WT) to improve fault detection and classification. The algorithm utilizes the Bi-Orthogonal 5.5 wavelet at level 1 decomposition. It considers factors such as fault resistance, series compensation, phase angle, and fault location. Fault detection relies on the analysis of detailed coefficients magnitude. Healthy phases exhibit low values, while faulty phases display high values of this detailed coefficient. Classification is achieved through threshold values applied to these coefficients. The proposed algorithm is validated on a 500 kV, 400 km and 50 Hz transmission line, demonstrating its effectiveness in detecting and classifying faults across various conditions. Results of the simulation show high accuracy and robustness, positioning the algorithm as a promising tool for ensuring the reliability and protection of transmission lines against different faults.