L-C band pass impedance matching coupling circuit for high voltage PLC applications

Abstract

This paper proposes a novel L-C band pass impedance matching circuit for PLC applications coupled to a Single Wire Earth Return (SWER) network via a 1.1 nF High Voltage (HV) Coupling Capacitor (CC). The work begins with characteristic impedance prediction of various SWER conductors followed by an analysis of the theoretical LC-resonant based coupling arrangements. A key finding is that high inductance and capacitance values are required for such LC-resonant based arrangements increasing the cost of solutions. An HV CC is then analysed and its effective capacitance is demonstrated, to be impacted by its internal protection circuitry. An L-C band pass matching circuit is then designed, built and tested as per the derived capacitance of the chosen HV-CC. The proposed coupling circuit produces only −4 dB insertion loss over the targeted 50 kHz to 150 kHz band and includes off-the-self components for a commercially viable solution. The design is based on the capacitance of an HV-CC and uses of off-the-shelf components setting this work aside from comparative works, which only considered hypothetical designs using unviable component values.