J. Marcos

Dynamic ramp-rate control to smooth short-term power fluctuations in large photovoltaic plants using battery storage systems

The changeability in the power produced by utility-scale PV plants caused by passing clouds can compromise power quality and reliability. Hence, some kind of energy storage systems (ESS) are required to reduce power variations below the limits imposed by new grid codes regulations. Here, we propose a novel control strategy to smooth out the fluctuations by using an energy storage system, namely dynamic ramp-rate control, which provides simultaneously a simple state of charge (SOC) control and 30 % less cycling degradation than classic ramp-rate control, as only is triggered when a fluctuation takes place. In addition, the strategy parameters can be tuned in order to reduce the capacity requirements by only modifying the SOC band values wherein the strategy is active. The novel techinque has been shown to work effectively with 5-s real power measurements recorded at the Amareleja PV plant (45.6 MWp, Portugal).

A tool for the performance evaluation and failure detection of Amareleja PV plant (ACCIONA) from SCADA

This paper describes a tool developed for the performance evaluation and failure detection in a 45.6 MWp PV plant installed by the company Acciona in Amareleja (Portugal). The paper describes the PV plant configuration and its SCADA (Supervisory Control And Data Acquisition), the measured variables and the main functionalities of the software. Some of these functionalities are the automatic and accurate PSTC (Power under standard test conditions1) calculation for each generator and for the whole PV Plant, the reference production that would be delivered by the PV plant assuming a 100% availability, the hierarchy of SCADA alarms, the detection of long-term trends and degradation in PV generators, possible hidden problems in the different equipment and systems composing the PV plant, etc. This tool entered into operation in 2011 and is working properly since then.