Research On Modeling And Grid Connected Capacity Of Photovoltaic Power Generation System

With the developing of photovoltaic(PV) power generation and grid connected technology, the permeability of PV power is getting higher and higher. If the capacity of PV power generation is too large, the instability of distribution network will be caused. Therefore, under the premise of no effect of the stability of the distribution network and provide an effectively guide for the future operation and planning of power, a model of PV system need to be established, the capacity of grid connected PV power generation system need to be analysed. On this basis, this paper carried out the following researchs:(1)Based on the equivalent circuit of the PV battery established corresponding mathematical model, and a practical simplified; Comparative analysis of the three kinds of maximum power point tracking control method, the incremental conductance method was been choosen; Using Park transformation, obtain the three-phase bridge inverter circuit rotating coordinate system of PV grid connected inverter mathematical model.(2)Based on DIgSILENT, the PV power generation system was integrated in the static generation. This PV power system simulation model has the functions such as output power with the change of environmental parameters, maximum power point tracking, active power dispatch and low voltage across. Through the simulation of environmental parameters changing, the node voltage changing and network fault, the validity of the model has been verified.(3)Take IEEE39 bus system for example, according to the safty of distribution network and stable operation of the constraints. The maximum grid connected capacity of PV generation system is simulated under the condition of different network and grid connected quantity and different distribution network topology. The main factors that affect the access capacity of PV power supply are network load, short circuit capacity and distribution network structure.(4)In the network of Turpan area, accessing PV station to three substations include Tuo Kexun, Da Langkan and Xiao Caohu to simulate. The largest PV capacity to the three were 46.5MWp, 47.5MWp and 48 MWp. Corresponding network loss were 20.54 MW, 21.23 MW and 20.25 MW. The capacity of PV access is the biggest in the Xiao Caohu substation and the network loss is the least. It can be used as the best grid connected point.