FAULT DETECTION OF PV SYSTEM USING ADVANCED SIMULATION

Abstract

The electricity from photovoltaic cells can be used for a wide range of applications, from power supplies for small consumer products to large power stations feeding electricity into the grid. For different applications PV modules are wired together into electrical circuits or arrays to provide the necessary PV-system voltage and/or current. In practice, all cells do not have identical characteristics. Therefore,• the cell with the lowest output would limit or control the module output. PV modules can be expected to fail in a number ways. The PV module characteristic changes due to different factors that make the PV module operate at fault modes. Some of these factors ; short-circuited cells or modules, open-circuited cells or modules, cracked cells, ground fault and shaded cells. The expected reduction in output power due to some of these fault modes is considered in this research. The shading of PV generator may occur on the cell in a module or the module in an array. The shade of a part of the cell is defined as partial shading. The partial shading is the most probable occurring in PV generator and it has a large effect on the produced power. Therefore, this type of fault is interesting for fault study to assessment the PV system perromance under fault operation. Modeling and simulation of PV generator under the shading effects are achived through advanced solar cell model to study one of fault losses in photovoltaic modules. An advanced model which is implemented in known a two-diode model, for the description of current and voltage characteristics of the solar cell. This model is able to describe the cell behavior in the generation region as well as in the breakdowns at positive and negative voltages. As the mathematical expression cannot be given in an explicit form, a MATLAB program is constructed to simulate the cell, module and array performance under different shading conditions. The effect of array configurations on the power loss at each shading level is determined. The 1-V curve of PV module is measured using implementation of the electronic circuit with a capacitor as a load. The simulation and experimental results for PV module show that the partial shading has cause high loss in performance. Shading of one cell reduces the power of the entire module by 70 % even though only 2% of the module area is shaded.