The Research On Reliability Of Power Line Communication In Smart Distribution Grid

To be the most important part of smart distribution grid, the construction ofcommunication system influence directly to the smart distribution grid. For thereasons as the communication media of power line communication is power line it self,and the communication performance is improving as the technical level, power linecommunication is an excellent communication mode of the communication system ofsmart distribution grid. But as the power line communication channel features ofimpedance, signal attenuation, noise suppression and multipath effects, the reliabilitythreatened the use of this communication mode.First, the paper integrates the communication modes of smart distribution gridand the application respects of power line communication, and current research statusof power line communication. The paper integrates the theory of power linecommunication and the concept of reliability and its evaluation indicators. After thatthe paper analyzes the communication channel of power line communication,especially the features of power line network, impedance, signal attenuation,apparatus noise. And then the paper establishes the channel model of power linecommunication.In order to grasp the noise characteristics of the power line communicationchannel, the paper measures several situations actually. Such as the noisecharacteristics of frequency conversion apparatus turn on, running, and turn off;Apparatus classified according the impulse noise they made, such as single pulsesperiodic pulses and continuous pulses, and measure the noise of these apparatus;attenuation characteristics of noise between different distances with the apparatus; thereal measurement of power line communication signal with background noise and soon.Then analyzes these measurement results with MATLAB.For the purpose of the enhancement of power line communication reliability,thepaper discusses automatic network at network layer and Error handling mechanism atdata link layer, focus on the analyzing of power line communication modulation modeat the physical layer.A kind of modulation mode combine both spread spectrumcommunication and OFDM. Spread spectrum communication has the advantage ofovercoming the noise interference. OFDM has the ability of mitigating theinter-carrier interference, anti-fading and anti-multipath interference. OFDM is themodulation mode that widely used nowadays in power line communication. The paper discusses the situation that to combine the CDMA technology witch based on spreadspectrum and OFDM. The new modulation mode MC-CDMA has the advantages ofthose two modulation modes, so that the ability of OFDM could be enhanced. At lastthe paper simulate the performance of MC-CDMA modulation modes with differentsignal-to-noise, the simulation results shows that MC-CDMA has the betterperformance than OFDM, the reliability of power line communication could beenhanced by the using of this modulation mode.