A New Zone Selection Scheme For Transmission Line Protection

In transmission lines, the identifying and differentiating faults from stressed states is extremely crucial. Generally, protection from faults in power systems is accomplished with the use of a distance relaying scheme. The Relaying scheme operates the Circuit Breaker (CB) using the ratio of transmission lines voltage to current. However, the traditional relaying schemes have a poor accuracy in differentiating the faults from power system stressed conditions like Power Swings and Load Encroachment. Transmission line protection plays a crucial role in ensuring the stability and reliability of power systems. Traditional zone selection schemes often suffer from inaccuracies due to dynamic system conditions and measurement errors. This paper presents a novel zone selection scheme for transmission line protection, integrating a Phase-Locked Loop (PLL)-based Phasor Measurement Unit (PMU) with Fast Fourier Transform (FFT) analysis. The proposed approach enhances fault detection and classification by accurately estimating voltage and current phasors in real time. The PLL-based PMU ensures precise synchronization and phase angle measurement, while FFT helps in identifying fault characteristics by analyzing harmonic content. By leveraging both techniques, the scheme improves the selectivity and speed of fault zone identification, reducing maloperations and enhancing the reliability of protective relays. Simulation results demonstrate the effectiveness of the proposed method in various fault scenarios, confirming its superiority over conventional zone selection techniques.