Transmission characteristics of low-voltage distribution networks in China and its model

Communication over the low-voltage distribution networks is of great importance to the electrical engineering and networks engineering. The signal transmission characteristics over the distribution networks are the key factors to be considered in designing the communication systems. In this paper, the signal transmission, characteristics in frequency band of 100 kHz similar to 400 kHz over 220-V distribution networks in China is investigated and its mathematical models are derived from the measured data. After the procedure of transmission measurement based on HP4395A is discussed briefly, the measurement results including in-phase and cross-phase transmission are described and analyzed. The impulse response of the channel is estimated from the frequency domain measurement based on the linear minimum mean square error in which the measurement noise is reduced during the parameters estimation processes, the estimation shows that the channel could be well described by the 20-taps finite-impulse response model. On the basis of a large amount measurements, we believe the transmission channel is the stationary stochastic process and a stochastic channel model of in-phase transmission is discussed and a six-order autoregressive of the channel model was given out.