Modeling and Interference Evaluation of Overhead Medium-Voltage Broadband Power Line (BPL) Systems

We analyze the radio interference from a Broadband Power Line (BPL) system operating between 2 MHz and several tens of MHz. The overhead medium-voltage (MV) power line is modeled as a 3-phase set of parallel wires above a lossy earth. A near-exact solution, based on previous approaches for infinitely long lines, is presented for the fields from arbitrarily long lines. Emissions are computed by considering a specified BPL model of semi-infinite length, and the maximum allowable excitation voltage vs. frequency is computed by assuming compliance with FCC field strength limits. These calibration results are used to study the interference to local terrestrial services and to quantify both the theoretical capacity and practical throughputs for BPL systems operation over [2, 30] MHz and [32, 60] MHz. We conclude that practical BPL throughputs are attainable while meeting current FCC requirements, but that these limits may not be stringent enough to avoid serious interference to neighboring radio services.