Photovoltaic (PV) Grid Power Generation System Island Detection Scheme

With the rapid development of current world economy,energy and environment problem is increasingly serious,make photovoltaic power generation with its advantages,the attention of more and more countries.In the next few years photovoltaic power generation will become the main operation of the electric power industry,its development speed is growing.Photovoltaic power generation but distributed power grid security problem such as large-scale grid of islanding,also more and more aroused people's attention.To put forward a lot of the world to the islands of the research plan of detection,to make the big progress,but there are a lot of problems to be solved such as: detection scheme,low efficiency of the blind area is too large,most studies of island detection scheme is only applicable in the single-phase system,and is not applicable to three phase.To solve these problems,this paper addresses the island detection scheme of photovoltaic grid power generation system research,the main content includes.(1)Firstly introduces the research background and significance of this topic,the general situation of the research and development at home and abroad,combined with a large number of references about the island detection at home and abroad,put forward in this paper,the main research contents and innovative points.(2)Photovoltaic power generation system are introduced,the basic component of understanding the important component of the structure of the classification of grid inverter,combined with the overall classification of grid-connected power generation system,topological structure and interconnection model parameters,establish internal structure model of photovoltaic power generation system to replace the traditional model of the dc power supply to generate electricity.(3)Introduces detection principle and the advantages and disadvantages of these methods of passive and Active,understanding of single-phase and three-phase systems applied in all kinds of detection methods on the difference and the causes of the difference,by analyzing the application in a three-phase system Active Frequency shift detection method of the essence,so as to put forward a kind of Active phase shifting type detection method instead of Active Frequency shift test three-phase system island.(4)In three-phase system adopts the combination of initiative and passive island detection scheme is effective,and traditional sliding Mode Frequency shift method of the proposed method algorithm of offset Angle is improved,the advantages of improved method are elaborated.And of the MATLAB simulation carried out to verify the above twoproperties.This article's innovation mainly has two points:According to in the single-phase system proposed by the combination of initiative and passive detection scheme,try using this detection scheme in a three-phase system,and successfully detect the island,to verify the effectiveness of the scheme.Combined with active phase shift method in simplified three-phase active frequency shift type detection scheme and the advantages of three phase current harmonic distortion,puts forward a kind of active phase shifting type sliding mode frequency deviation method to detect the island in a three-phase system;Innovation put forward an improved type of SMS again detection method,the principle of this method are introduced in detail,the algorithm and performance improvement,through MATLAB simulation test and verify the superiority of the improved method.Damage caused by islanding itself,and this study can clean energy on a large scale in the current grid environment,timely and effective to detect the island in a three-phase system,guarantee the safe operation of the photovoltaic grid system,has the vital significance.