Research On Modeling Of The Medium-voltage Power Line Channel Noise Considering The Low-voltage Feedback Noise

Medium voltage power line communication (MV-PLC) technology is one of theimportant communication modes in the smart grid applications. The main factorsaffecting the reliability of power line communication are the noise interference,signal attenuation, and input impedance, etc., and the noise interference has thebiggest influence. So it is necessary to study and analyze the noise characteristics ofthe medium voltage power line and research on the modeling of power line channelnoise in depth.The characteristics of MV power line channel are elaborated in detail, includingnoise, attenuation and impedance. The measuring circuit is built and abundant actualnoise data is measured and analyzed. This paper first puts forward considering theLow-Voltage (LV) feedback noise coupling through distribution transformer in MVpower line when studying on the MV power line noise.The autoregressive model of power line background noise is established.Respectively, Levinson-Durbin method, Burg method, Improved covariance method,and Gram-Schmidt orthogonal method are applied to calculate the model parameters,and the characteristics and applicable conditions of these methods are analyzed andcompared. Based on the measured noise data, a complete Markov chain model ofrandom impulse noise is established. This model considers the main parameters ofimpulse noise, including the impulse noise amplitude, width, and time interval.In order to study the feedback noise coupling through distribution transformer inMV power line, the high frequency transmission characteristics and port impedancecharacteristics of distribution transformer are measured, and a high frequencytransformer model is set up. Through comparing the measured data and the Matlabsimulation results, the correctness of the model is verified. And according to the highfrequency transmission characteristics of the distribution transformer andtransformer’s own characteristics, feasible methods of feedback noise restrain areproposed to improve the noise environment of the MV power line channel.