Research On The Integration Of Distributed Photovoltaic Power Generation Into Distribution Line

With the development of new energy technology,more and more distributed photovoltaic power is incorporated into the distribution line,which changes the topology of the original distribution line,affects the power flow direction of the distribution line,changes the fault characteristics,and affects the protection configuration.Firstly,this paper investigates and analyzes the structure and principle of distributed photovoltaic power generation system,and then establishes the model.Secondly,after the distributed photovoltaic power is integrated into the 35 k V neutral ungrounded distribution line,the fault characteristics of short circuit fault before and after the distributed photovoltaic power is connected are analyzed,and the influence of the distributed photovoltaic power on the fault current is discussed,and the simulation model is built in PSCAD to analyze the influence of the fault characteristics combined with the actual situation.Due to the access to distributed generation,the fault characteristics of transmission lines have changed.Then,according to the changed fault characteristics and the requirements of State Grid documents,this paper proposes a no channel protection scheme,and verifies the effectiveness of the protection algorithm on the RTDS experimental platform.Finally,under the feeder protection platform of the relay protection research group of Tsinghua University,we participate in the development of the protection device and upper computer after the distributed photovoltaic grid connection,and meet the protection requirements after the distributed photovoltaic grid connection from the reality.The access of distributed photovoltaic power makes the fault current of single-phase to ground fault,two-phase to ground fault and two-phase to phase fault changed compared with the original distribution line.The distributed grid connected protection device is applied to Yulin distributed access distribution line.The test results show that the no channel protection scheme after distributed photovoltaic access can effectively and quickly remove the fault from both ends of the line.