Rasearch On The Improvement Scheme Of Distributed Photovoltaic Acess System

In today's society increasingly nervous energy, the environment pollution is serious, solar,wind and other renewable energy to get attention from all walks of life and study. After the PV power grid, however, will change the original distribution network topology structure, the direction and short circuit current trend, these changes are to have serious impact on the existing distribution network protection. Therefore, it is necessary to research into photovoltaic power supply distribution network after the new protection scheme.Firstly, this article summarizes the classification and main components of photovoltaic power generation system, build a model in the Matlab/Simulink simulation software, to verify the changes under the condition of the outside world the photovoltaic cells output characteristics and disturbance observation maximum power tracking performance of the algorithm.Theory analyses the action of the protection of traditional distribution three-step current conditions and scope of protection, in PSCAD simulation software with photovoltaic power supply of 10 kV distribution network model is established, the photovoltaic system in the traditional distribution network access to the three-step current protection and the effect of contrast analysis of the photovoltaic access before and after the change of the distribution of short-circuit current waveform, the results show that solar access system after the fault location and photovoltaic access position and the effect of the original three-step current protection can not reliable action.Finally, in view of distributed photovoltaic power grid, puts forward the adaptive current protection based on the composite sequence network, and in view of the specific example, the calculation of the set values for the adaptive improvement, building model in PSCAD simulation, contrast the set values for the improvement and the simulation results, the effectiveness of the scheme is verified, and can improve the reliability of protection.