Research on Channel Characteristics of Energy-Information Integrated AC Transmission System

With the rapid development of distributed generations, power-electronics based equipment is being widely deployed. Communication capability should be endued to these equipment to fulfill long-distance coordination. Considering the potential of digital signal modulation embedded in power electronics converters, the energy-information integrated transmission (EIT) technology is a promising approach to fulfill power transmission and signal communication with a unified circuit; however, the EIT technology is usually used in dc distribution systems since the ac system is more complex in high-frequency wave generation, signal separation and processing. For achieving practical implementation of EIT in ac systems and providing a reference for parameter and software design in EIT communication systems in smart grids, it is essential to analyze and model the characteristics of the ac transmission channel and evaluate the information-carrying capacity of ac systems. This article establishes a model of the ac transmission channel consisting of power electronic converters (PECs), power lines, and loads. The integral channel characteristics are derived after each component of the channel is analyzed. The models of the point-to-point channel and multipoint communication channel are conducted and analyzed from the perspectives of signal transmission and power harmonics. Simulation and experimental results demonstrate that the proposed model accurately describes the characteristics of the EIT channel in ac system.