Research On Fault Detection Of PV Array

Hot Spot is a main problem of PV arrays. It may not only reduce the power output of photovoltaic power generation system, but also bring about problems about security and reliability. It is internationally recognized that connecting the PV cells in parallel opposed bypass diodes can avoid Hot Spot. Bypass diodes can extend the life of components, but it may cause some other problems, such as the requirement of a number of cell monomers and the power loss of PV arrays associated with the current passed through bypass diodes. At present, detecting the occurrence of Hot Spot commonly bases on the infrared image analysis. However, this method presents some unavoidable shortcomings, such as its inferior discernment in the minor temperature differences, poor real-timeliness, hamstrung malfunction analysis and alarm online, low accuracy and efficiency at present stage.Based on the comparison and analysis of four basic structures about Photovoltaic arrays, this paper presents an improved connecting type of solar array - CTCT (complex-total-cross-tied array) structure and puts forward a photovoltaic array fault detection system. Fault detecting results can be got through the introduction of data fusion theory to fault detection algorithm to process the data. In addition, this paper studies this system costs and the detection accuracy, proposes the formula used to demonstrate the relationship between current sensor number and resolution. This study is useful for cost control on the basis of sufficient detection accuracy in the actual fault detection system.By Matlab/Simulink, fault detection algorithm on the PV array simulation experiments confirms the validity of the algorithm. Finally, through building the hardware circuit, experiments were carried out on partial shade and all light outdoor conditions. Experimental results show that the processed data obtained from the fault detection algorithm can detect the location of partial shade. Correctness of this new fault detection algorithm is proved by the experimental results.