The Research Of Reverse Power Detecting Method At Grid-Connected Photovoltaic System Based On Transient Wave

Solar energy as a clear renewable new energy gets the increasing favour of people, and that converting solar power into electrical energy is an important way to solve the energy problem. The grid generation method is worth to be considered to make solar power system play a practical value. However, the uncertainty of the load power in the power grid system may cause risk of solar electric power flow to the mains.Given that the problem of reverse power could be produced in the process of the Grid-connected Photovoltaic System, a new idea, characteristic wave detection and control using the transient process theory and transient protection theory in the power system is suggested. Namely, transient waves of all kinds of load can be captured by the sample processing system with a core of F28335DSP when some loads change their current situation. Using FFT algorithm for sample data can get typical feateures carried by the transient waves of all kinds of load, and the relationship between transient waves and loads change event can be confirmed. The reverse power event can be judged with characteristic waves model library by checking electric power signal.In the small Grid-connected Photovoltaic test platform, a relay circuit controlled by key operation is designed to control the action of loads.Sampling circuit is designed to capture the transient wave when one load changes its switching state. FFT algorithm is designed to analysis the sampling data. Matching and positioning algorithm based on statistical indicators is designed to establish model library. The model realized 100% correct recognition rate for load change event and 80% correct recognition rate for specific load change event when it is tested in the test platform.