Research And Design Of Distributed Monitoring And Communication System For Photovoltaic Power Station

Photovoltaic industry has been rapid development in recent decades,as well as the research in photovoltaic power generation monitoring system has also made a lot of advanced results.In order to monitoring the actual operation state of each solar PV module in the PV plant,it is necessary to develop a PV module monitoring module which communicating with each other by the DC single wire between the PV modules,On this account to realize PV monitoring and communication system at the module level.In this paper,by analyzing the equivalent circuit model of solar PV module and PV modules in series,the paper discusses the possibility of the DC and AC channels existing in the solar PV module and PV modules in series.On the basis of the possibility,this paper presents a communication method which utilizes the DC single wire between the PV modules as the channel of carrier communication.The overall design scheme of photovoltaic monitoring module based on DC single wire carrier communication is expounded.The influence of the parasitic parameters on the carriers signal transmission is studied emphatically.Based on the study of the impedance characteristics,noise characteristics and channel characteristics of the solar PV module and PV modules in series,it is proved that carrier communication on the solar PV module and PV modules in series is completely feasible.And the best signal frequency of the carrier communication on PV modules is 200kHz.On the basis of the design of the AC carrier signal coupling circuit,the DC single wire carrier transmission test between the solar PV modules is carried out.According to the experimental measurement results,the AC carrier transmission model on the PV modules is established,and the theoretical simulation and analysis about the model is carried on.At last,the hardware circuit of the PV module monitoring module is designed and verified experimentally.The PV module monitoring module which designed to monitor every PV module in the PV plant is of great significance for PV power plant to reduce the operation and maintenance cost,and also improve the operating stability of the PV power plant.