Measurement and cognitive detection method of broadcast radio stations in distribution networks

Power Line Communication (PLC) plays a major role in smart grid applications. However, when the frequencies of above 500 kHz are used, mutual interferences between the PLC access system and Medium Wave (MW)/Short Wave (SW) broadcast radios may occur. To cope with this issue, one of the promising solutions is cognitive PLC. In this paper, MW/SW broadcast radio frequency allocation and their usage conditions in China are reviewed first, to get experience with their potential frequency collisions with PLC. Then the results of a measurement campaign performed in the typical Low Voltage (LV)/Medium Voltage (MV) distribution networks in China are shown and analyzed in detail. Besides individual measurement snapshots, more statistical results are investigated to reveal the variation of the radio interference level with different measurement places and times. All these efforts contribute to obtaining the Reception Factor (RF) of the measured distribution networks, in conjunction with the narrow-band noise peak level over the power line noise floor. On that basis, a threshold-based cognitive detection method is proposed to identify radio stations on the distribution lines. Finally, the paper ends with brief discussions of the impact on PLC throughput when dynamic notching is employed.