Study On Photovoltaic Power Station Clustercoordination Control And Its Monitoring System

Photovoltaic(PV) power generation technology owns a long history, which take advantage of photovoltaic effect, converting solar radiation to electric energy. Recently, due to the industrialfossil fuelsburning, the environment got damaged and so that PV power generation attracted much more attention. However, PV technology has its own insurmountable defects:The volatility of power output is difficult to control, which hindered its popularization. The common practice andresearch direction on this issue is to use charging and discharging of battery or super capacitor to alleviate PV output fluctuations. But limited by characteristic of energy storage device, it is still difficult forwide range promotion. At the same time,on account ofthe low accuracy of photovoltaic power prediction nowadays, employ energy storage is difficult to fill a largerpower vacancy.For the sake ofmuch more PV plants workinggrid-connected, this thesis studied a method based on cluster coordinated control, stabilizing the PV power volatility via coordinate operation of multiple PV station in large areas. The core idea is:(1) BringPV plants together to optimize the overall control. (2) Each sub-station reserve amount of power regulation ability, to balance probably power gaps of other PV sub-stations. (3) Upgrade the current PV monitoring a digital system to achieve broadly interoperability between photovoltaic equipments and plants.To begin with, this thesis analyzed the basic theory and fundamental devices of PV generation, including the volt-ampere characteristic curve under different environmental conditions of PV modules, the DC voltage regulating device, inverter, and the energy storage device. Then, the control methods of PV power station are emphatically studied. It contains maximum power tracking control, differential control, inverter active and reactive power output control, short time mitigating power fluctuation control. Moreover, for the sake of the acquisition of PV cluster coordination control, this article proposecentralized and distributed coordinated control strategy. The centralized way is to gather all information of sub-station, and set minimum of energy storage output as the target, constrainted by storage capacity and power generationplan. Distributed coordinate control takes advantageof the communication between PV sub-stations in a cluster. Running distributedcontrolprotocol to realize the collaboration. Finally, this article designed a kind of PV cluster digital monitoring system,aiming at realize a broader compatibility. This part of study is mainly for digital PV devices and operation with digital equipments.The full text analyzed the control strategies and algorithms of PV power systematicly, proposed two kind of PV cluster coordinate control method:centralized optimization and distributed coordinate control. Studied and implemented the digital PV cluster monitoring according to the need of PV cluster control. The case studies in the text had shown the effectiveness of the two kinds of PV cluster control methods, and shown its worthy of further research.