Effect of couplers and line branches on PLC communication channel response

For Smart Grid and Power Quality measurements, a communication system is required to sent tariff information and measure Voltage, Current and Power as well as reading a smart electricity meter. James Cook University is carrying out research on using Power Line Communications (PLC) signals on Single Wire Earth Return (SWER) lines for Smart Grid applications and Power Quality assurance. For SWER lines, the characteristic impedance of the line changes with frequency and the radiation losses sharply increase with frequency. This paper describes an accurate SWER line model, which incorporates these frequency dependencies to demonstrate the severe signal channel degradation that can occur due to line branches and coupling networks. This model is applicable to any power line. The model is verified with measurements from two sites. Data rates at 22.8 kbps with more than 14 dB excess CNR were obtained on a 14 km SWER line.