COMPUTER-BASED MODEL FOR STUDYING THE OPERATION OF THE PHOTOVOLTAIC STATION WITH FUZZY REGULATOR OF THE GRID INVERTER
Computer-based model of 250 kW photovoltaic station, consisting of 88 parallel strings, each of which contains 7 serially connected modules of SunPower SPR-415E-WHT-D type, connected to the local electric grid was developed, applying Matlab programs. Such model enables to carry out the study of the operation of the station with fuzzy regulator of the grid inverter, based on the mathematical model of the electric energy generation process optimization in the grid at photovoltaic station, applying fuzzy sets tool.
For the verification of operation adequacy of the photovoltaic station fuzzy regulator the modeling was performed for two cases of electric station operation: with fuzzy regulator and without it. The following condition was met - the loading, climatic conditions and their change was identical for both cases. The greatest impact in the process of electric energy generation by photovoltaic station has the sudden cloud coverage, that leads to the decrease of the amount of solar radiation per unit of the surface area. As a result, electric energy generation drastically drops. That is why, in the process of modeling this parameter played the most important role. Besides the climatic factors, the carrying capacity of the grid has great impact on the process of photovoltaic station generation. Thus, in the process of modeling such modes as electric energy consumers load drop, load increase and simulation of drastically changing climatic factors, for instance, sudden cloud coverage were simulated.
Modeling was performed in the time interval from 0 to 0.2 sec. This was sufficient for the assessment of photovoltaic power plant operation in the above- mentioned modes. In the computer model active-inductive loading was used for obtaining the conditions, maximally close to real conditions, in its turn, this enabled to obtain information, regarding the generation of active and reactive power by photovoltaic power plant. For the correct assessment of the grid parameters phase currents and linear voltage of photovoltaic power plant were evaluated.
The obtained results prove the efficiency of the fuzzy regulator application, the correctness of the mathematical model and the necessity of taking into consideration the impact of the climatic factors, carrying capacity of the grid on the control of the process of the electric energy transmission by the power plant into the grid.