Power quality assessment of grid-connected photovoltaic plant

Abstract

In the twenty-first century, the cost of production of electrical power from solar and wind energy has become highly competitive to the power from conventional sources of energy. Besides the stand-alone and comparatively smaller photovoltaic systems, large photovoltaic plants for the generation of electrical power have become quite common. These large sources integrate the electrical power with existing power grid. In this work, an assessment of the quality of electrical power was made by the measurement supplied by two 50-kW gridconnected photovoltaic plants at IIT Jodhpur. The requirements of power quality by International Electrotechnical Commission (IEC) have been taken into consideration. Parameters, for example, total harmonic distortion (THD) and crest factor (CF), and AC indices such as apparent power, real power, and power factor are analyzed with the help of power analyzer. The quality of DC power delivered by PV module and measured at DC/DC boost converter was also analyzed. It is a great concern for the operation of DC/DC microgrid. It was found that the quality of power supplied to the grid was highly affected by inverter design. The maximum THD in the voltage supplied to the grid was measured to be within the limits. The voltage swells and sags were found to be absent at both the plants. The ripple in DC power delivered by the PV modules was measured to be greater than the permissible limits.