Measurement Methods of Outdoor Low-Voltage Cable Characteristics for Narrowband Power Line Communication

A total of three measurement methods are presented for low-voltage cables characterization in the frequency band used for power line communication (9-500 kHz). In this paper, the cables are considered as composed of a set of simple transmission lines free from mutual coupling. The characteristic impedance and propagation constant as a function of the frequency have been assessed. In the first method, an LCR meter has been used to measure the input impedance of the cable, while the output is step-by-step short and open circuited. In the second method, a network analyzer in a reflection mode is used to measure the input impedance. The third method consists of measuring the scattering matrix (S-matrix) of the cable using a network analyzer. These measurement methods have been validated and compared using a well-known coaxial cable. In addition, the measurement reproducibility and the drift of the measuring devices are evaluated. Finally, two power low-voltage cable technologies, underground cable and overhead line twisted cable, are characterized by the most accurate method. The cables losses have been also investigated.