A non-unit adaptive pilot protection for HV transmission line interlinked with off-shore grid scale wind energy and controllable series compensator
Year: 2025
Type: article
Abstract: Conventional non-unit distance relays often malfunction when protecting transmission lines integrated with large-scale wind farms and series Flexible AC Transmission System (FACTS) controllers such as the Thyristor-Controlled Series Capacitor (TCSC). These mal-operations, commonly over-reaching and under-reaching, are primarily caused by the variable fault current behavior, low zero-sequence impedance of wind farms, and the nonlinear dynamics of Doubly Fed Induction Generator (DFIG) systems and series compensation modes. To overcome these limitations, this paper proposes a simple and robust protection scheme that performs fault detection, classification, and location estimation using synchronized measurements from both line ends. Fault detection is achieved using a Disturbance Gradient Index (DGI) derived from negative-sequence current signals. A rule-based classifier utilizes the Moving Variance Index (MVI) and phase angle features of the superimposed sequence components for fault type identification. Finally, a double-ended traveling wave-based fault location algorithm is implemented using Park’s (DQ0) transformation and Dual Tree Discrete Wavelet Transform (DTDWT). The scheme was validated using a 500-kV, 300-km two-bus transmission line model in MATLAB/Simulink under a wide range of fault types and system conditions. The proposed method achieved 100% fault detection accuracy, 98% classification accuracy, and fault location error below 1.1%, with a total decision time under 8.1 ms. Performance remained stable under high-resistance faults (up to 250 Ω) and noise levels as low as 10 dB. Comparative analysis with previous methods confirms the proposed scheme’s effectiveness, speed, and noise robustness for real-time protection of modern transmission systems.
Source: Results in Engineering
Authors: Andaleeb Ali, Attaullah Khawaja
Institution: NED University of Engineering and Technology
Language: English
Subfield: Control and Systems Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,940
OpenAlex ID: W4413289914