Long Term Wind Turbine Performance Analysis Through SCADA Data: A Case Study

Performance monitoring of horizontal-axis wind turbines is a complex task because they operate under nonstationary conditions. Furthermore, in real-world applications, there can be data quality issues because the free stream wind speed is reconstructed through a nacelle transfer function from cup anemometers measurements collected behind the rotor span. Given these matters of fact, one of the objectives of the present work is applying an innovative method for correcting the nacelle wind speed measurements, which is based on the manufacturer power curve and statistical considerations. Three operating wind turbines, having 2 MW of rated power and owned by the ENGIE Italia company, are contemplated as test cases. Operation data spanning ten years (2011–2020) are studied: actually, this work aims as well at contributing to the methods for estimating the performance decline with age of wind turbines, basing on long term SCADA data analysis. The raw and corrected wind speed measurements are fed as input to a Support Vector Regression for the power curve: by selecting appropriately the training and validation data sets, it is possible to estimate the average yearly rate of performance decline. Using the corrected wind speed, the estimate obtained in this study is compatible with the most recent findings in the literature, which indicate a -0.17% decline per year

Voltage Control in Low-Voltage Grids Using Distributed Photovoltaic Converters and Centralized Devices

This paper studies the application of distributed and centralized solutions for voltage control in low voltage (LV) grids with high photovoltaic (PV) penetration. In traditional LV grids, the coordination of distributed PV converters and a centralized device would require massive investments in new communication and control infrastructures. The alternative of exploiting distributed PV converters for voltage control is discussed, showing that it can help to stabilize the voltage in the grid connection points also without coordination between them and/or with a centralized unit. The goal of this paper is to investigate how the setup of the voltage controllers inside PV inverters affects the operation of these controllers taking into account the limits for reactive power injection. In addition, the interaction of distributed PV converters with centralized devices (static var compensators and on load tap changers) is analyzed to assess whether additional benefits may come in these cases

Emergent In Situ Fenestration in the Ascending Aorta for the Endovascular Repair of a Large Pseudoaneurysm: A Technical Note

The purpose of this article is to describe an emergent in situ fenestration (ISF) technique in the ascending aorta for the endovascular repair of a large pseudoaneurysm using a trans-septal needle device through direct right common carotid artery access, in a patient with left ventricular assist device (LVAD)

Ageing effect on the performance of A-Si photovoltaic modules in a grid connected system: experimental data and simulation results

To test performance and ageing of amorphous silicon photovoltaic (a-Si PV) modules, an Italian Electric Company (AEM Spa-Torino) has installed a PV system (12 kWp) connected to a three-phase grid. As is well-known, the performance of a PV field depends on irradiance, module temperature and ageing. In order to separate the ageing effect from the irradiance and temperature influence, it is necessary to know the beginning of life (BOL) performance, at the irradiance and module temperature, measured during the life of the PV field. The deviations, between the experimental data and the BOL performance, provide the ageing of the PV modules. This paper proposes a simulation procedure that gives the BOL performance and allows determination of the monthly and yearly ageing of the PV field. The simulation results, related to the 12 kWp field, are reported. This procedure can be also applied to stand alone PV systems with modules of different technologie