Research On The Technology Of Islanding Detection For PV System Grid-connected

Energy is supplied to the high-speed development of the world economy.Not only limited for the reserves of conventional fossil energy sources,physical deterioration of the ecological environment will be generated in the process of energy consumption.It seems imminent to develop clean and renewable energy.World vision was put into solar energy,as the world's most abundant clean energy,because it being not subjected to geographical restrictions,easy to collect,no mining and transport,etc.However,with the growing capacity of photovoltaic power generation in each regional power grid,great challenges have been brought to the power system.Especially when islanding occurs,it will be a huge threat to bring the electrical equipment and maintenance personnel.Therefore,it has a very important social and economic value to carry out islanding detection technique for photovoltaic power generation system grid connected.Firstly,some fundamental questions on islanding have been studied,such as the mechanism of islanding,islanding detection standards,islanding detection methods with its performance evaluation,anti-islanding detection,etc.Then,islanding detection method is divided into two categories,depending on whether destructive,and various methods are briefly introduced.After that,the starting point of islanding detection theory was summarized,binding studies trends of islanding detection methods.Secondly,it pointed out that the literature did not analysis the mechanism of negative sequence voltage of the PCC and the selection of positive feedback coefficient in the negative sequence voltage positive feedback.And from these two points of view,the mechanisms of negative sequence voltage of the PCC and the selection of positive feedback coefficient have been analyzed in detail.Then,the islanding detection method base on adaptive negative sequence voltage positive feedback is presented.Negative-sequence disturbance proved to be the smallest,through theoretical analysis and simulation,during adaptive negative sequence voltage positive feedback process,to ensure that every moment is to meet the requirements of islanding detection.Thirdly,anti-islanding detection system design scheme is introduced,and development processes of the transformer control room container,load container,control system has been analyzed in detail.Anti-islanding test program has been developed,with field testing being performed.Finally,the work has been summarized and its shortcomings has been pointed out in this paper,and future research directions are suggested.