Impact of Photo Voltaic Cells on Hybrid Microgrid

Abstract

In order to reduce the green house gas emissions all over the world the investment on renewable energy infrastructure is increasing particularly in the distribution network. It is also observed that the power generated by distributed system is not only supplied through distribution system but also fed to the grid by appropriately transforming the voltage. It has the advantage that the power generated through distributed generation system is utilized in the grid for other users. The PV cell generates voltage at the distribution level. At the end of distribution line a 1 MVA three phase load is connected. In the absence of the generation from the PV cells, the voltages and currents at various lengths of the line are calculated with a single load of three phase 1 MVA. With the inclusion of PV cells, the improvement in voltage dip is also estimated. This estimate provides the power supplied by the PV cell and improvement in voltages. In order to determine the effect of additional load on voltage profile, a three phase load of 1 MVA was connected to intermediate point in the transmission system. This causes the dip in voltage at various nodes of the distribution line. Several combinations of source and loads have been examined to determine the effect on voltage and power. The above work has been carried out using Electro Magnetic Transient Program (EMTP), free version developed by university of British Columbia, Canada and made available through Indian EMTP user group. In order to simulate the system, 8.98 kV 5 km long line is divided into 5 sections of 1 km each. The sections are represented in the form of Pi-network by its series inductance, resistance and capacitance to ground. Loads are represented by R and L of appropriate magnitude and through EMTP program the calculations are done. The PV cell is represented by a source stepped up to 8.98 kV system. Both single phase and three phase lines have been examined through the above program. The results obtained for various conditions are presented in the paper.