Beqirllari, Kristi ORCID: https://orcid.org/0009-0006-3912-5654 (2025) Innovative Power Line Communication Solutions for Enhancing Safety and Signal Integrity in Single Wire Earth Return Systems. PhD thesis, Victoria University.

Abstract

Given the increasing frequency of extreme weather events due to climate change, the robustness of the power infrastructure has never been more critical. When a powerline conductor breaks and falls to the ground, electric current flows through the contact surface, forming an electric arc causing bushfire hazards and posing a threat to human life. The detection of such disturbances has long been a challenge for engineers with no conclusive solution. This thesis seeks to develop a reliable method for identifying broken conductors in power networks using Power Line Communication (PLC) technology. The first significant outcome of this thesis is an innovative AC mains interface, specifically designed to enhance the efficiency and safety of PLC systems within Single-Wire Earth Return (SWER) networks. It incorporates a versatile board, allowing for precise impedance matching across various SWER configurations. Extensive simulations and field tests have demonstrated that the developed AC mains interface, when combined with optimized transformer turn ratios, significantly improves impedance matching across various SWER configurations. A second major contribution of this thesis is developing an advanced coupling circuit design approach, optimized using a MATLAB-based algorithm. This advanced method treats the matching circuit as a black-box model, systematically calculating the optimal values for inductors and capacitors to achieve precise impedance matching between the source and the load. This approach is easy to implement, and tested across various coupler configurations using different cost functions and target mean error levels. Another key innovation is a novel receiver signal-conditioning circuit, offering flexible signal control with variable attenuation, amplification, and a tunable band-pass filter. This design aims to overcome limitations in accessing lower frequencies in MV SWER networks, which stem from high low-frequency cut-off and substantial insertion loss in conventional coupling capacitor designs. The final major outcome of this thesis is a novel Auto-Regressive (AR) modeling framework that accurately captures complex noise dynamics in SWER networks, addressing limitations of traditional methods. Empirical tests confirm the model’s effectiveness, with a predictive accuracy rate exceeding 95 %. This thesis systematically presents the conducted research and findings. Chapter 1 introduces the study’s motivation, research objectives, and key contributions. Chapter 2 provides a comprehensive literature review, discussing impedance matching, coupling circuit design, and noise modeling in SWER networks while identifying critical research gaps. Chapter 3 explores SWER transformer access impedance and presents a novel impedance-matching interface to enhance PLC signal transmission. Expanding on this, Chapter 4 details the design and implementation of a wideband signal-conditioning circuit, improving transmission performance. Chapter 5 introduces an S-parameter-based optimization approach for coupling circuit design, employing a MATLAB algorithm to achieve precise impedance matching and minimize signal attenuation. Chapter 6 focuses on the development of an Auto-Regressive (AR) modeling framework for impulsive noise characterization in SWER networks. Finally, Chapter 7 summarizes the key findings, emphasizes research contributions, and outlines potential directions for future work.

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