Research On Simulation Of PV Station Model And Grid-Connected Operating Characteristics

With the heavy investment and strong support our country devoted to PV generation industry, PV station connected to the utility grid at home has already widely developed and commercially operated, and will still remain a development tendency in the future. However, PV station connected to the utility grid brings impacts which cannot be ignored on the electric quality, power flow distribution, short circuit characteristic and so on. Thus, carrying out PV station connected to the utility grid technology research is of great importance.Based on the5-parameter model of PV module equivalent circuit, an equivalent correction algorithm is proposed in this paper to obtain the parameters of PV module5-parameter model. Just by using the actual experimental data provided by PV cell manufacturers, the five parameters will be determined after a few iterations and correction calculations. Acquire the5parameters of MSX60PV cell with the above algorithm, simulate the PV module model with the parameters obtained in previous step, and compare the simulation data with the measured data. As a result, the-mistake is relatively small. Accordingly, the accuracy and effectiveness of the equivalent correction algorithm of PV module5-parameter model are thus verified.Lambert-W function is brought in to make the implicit PV module I-U characteristic equation in form of transcendental equation explicit. PV array simulation model is established in Matlab/Simulink. Run the model with actual operating data of a certain array in a Qinghai PV station applied, and analyze the reasons that cause the mistakes between simulation results and actual measured data. As a result, the simulation model is validated to be accurate and feasible.The relationship between voltage and current of each part of the whole grid-connected PV system is analyzed and shown in form of equations. With the application of KVL (Kirchhoffs Voltage Law) and KCL (Kirchhoffs CurrentLaw) at the connection point, the equations are combined to form the entire grid-connected PV station system transient model expressions. In Matlab/Simulink simulation environment, grid-connected PV station system simulation model is built and run under various solar irradiance and cell temperature, having verified the simulation model’s correctness and feasibility.A grid-connected PV station system power flow calculation strategy is put forward, which applies PV station parameters to network parameters. Based on conventional current injection model Newton-Raphson (N-R) algorithm, some improvements are made, proposing a current/power hybrid injection-based model N-R power flow calculation algorithm. Applying several IEEE classic examples, the hybrid injection model power flow calculation algorithm is tested to be superior, accurate and effective. With parts of the PV arrays in a Qinghai PV station accessing to IEEE30system as testing case, the grid-connected PV station system power flow calculation strategy is validated to be feasible.Connect a PV station with certain quantity of power output to the NO.1bus of IEEE5system. Different kinds of short circuit fault are set respectively at PV station inner AC system and grid-connected point, exploring the grid-connected PV station system short circuit operating characteristics.