ENERGY LOSS CAUSED BY SHUTDOWNS AND STARTING IN GRID-CONNECTED PHOTOVOLTAIC INVERTERS

摘要

In this study, the performance of a 4.3 Kw_p grid-connected PV plant located at the CIBA (Low Atmosphere Research Centre) in the Region of Castile and Leon (Spain) was evaluated by means of the system yields and energy loss with regard to weather conditions, mainly in the form of available solar irradiation. A statistical study of the irradiances has been made when the inverters' starting and shutdown take place, obtaining an asymmetric frequency distribution. 90% of the values are between 40 and 90 W/m~2. As a result, energy losses have also been calculated. Loss has been studied as a function of the solar irradiation values and the results obtained are fitted to a function of the type: P (%) = Ah~(-b) where P are the losses in%,H the daily irradiation and a and b are two parameters of the function. Daily inverter output energy has been studied taking into account the global daily solar energy on the array plane, and a lineal regression for the variables has been obtained. The total energy loss is given by ordinate y-axis.