Research Of Medium Voltage Power Lines Channel Transmission Characteristics Based On Multi-conductor Transmission Line

As a unique means of communication in power system, power line communications can take advantage of existing physical network to communicate, with small investment, flexibility, high network reliability. Different from the traditional communication channel, medium voltage distribution network power line communication channel has the unfavorable factor of lossy, noisy, high impedance range and other. In order to meet smart grid’s requirements of high-speed, high reliability for distribution network power line communication, it is necessary to study the medium voltage power line channel characteristics.According to the analysis and measurement of the medium voltage power line channel attenuation characteristics, it indicates that the attenuation depends largely on line topology and high-frequency parameters of the main electrical equipment. A channel model based on multi-conductor transmission line theory and bottom-up method is proposed, and its accuracy is also verified with the help of MATLAB and PSpice simulation.The characteristic parameters of medium voltage power line is closely related to the primary parameters of the three-phase transmission line. A method of calculation the distribution parameters based on the power line network topology is described, its accuracy is also verified by actual measurement. Based on the model of the uniform transmission line and branch line, applying the network cascade principle, the overall model of medium voltage network is established. Comparing with the actual measurements to verify the accuracy of the model. Finally, the transmission characteristic of medium voltage power line network is analysed, which provides guidance for the actual communication system design.Channel noise is one of the important channel characteristic parameters. The noise of medium voltage power line is very complex and not Gaussian white noise. It mainly includes background noise, narrow-band noise and random impulse noise. Applying power spectrum estimation theory and Markov model theory, the medium voltage power line noise model is established.