Rafael B. Oliva
UNPA + L&R Ingeniería
Rio Gallegos – Santa Cruz – Argentina
Battery-charging applications using small wind power are an attractive solution for isolated rural systems with limited electric power consumption, specially in arid regions such as South Patagonia where the solar resource is less significant. Early wind power installations for battery charging using American Windchargers were popular in the first half of the twentieth century, although reliability problems and cheap petrol solutions relegated their use for decades. The first generation of machines using permanent-magnet generators and advanced electronic regulators were imported, but local technology for these systems has grown slowly since the mid-90’s, and today about 16 firms within Argentina are producing systems based on AC generators and rectifiers with furling power limitation, plastic or wood rotor blades, and increasingly complex regulator and inverter designs, with mixed economic results. After the 2001 devaluation in Argentina, substituting formerly cheap imports began to make sense and the industry expanded. Reliability and quality issues are still a problem, specially for systems installed in South Patagonia where strong summer winds cause mechanical and electrical failures. Cost is also a major barrier for industry expansion, because even for non-imported wind turbine and BOS (Balance of System) equipment, the price of the installed nominal kW remains in the usd 4K to 6K range, very high for local standards. In addition, some kind of alternative backup power source such as Diesel is normally required if the load supply is critical -specially in winter, when wind resource is weakest. Finally, lack of effective local maintenance structures and difficult replacement-parts supply further complicate wind machines’ performance record. All these issues make measurements performed on systems very important, if cost-effective and reliable wind powered chargers are to be developed. Since 2011 the INTI (National Institute for Industrial Technology) initiative for small-wind power has been supporting this industry, mostly composed of small firms, and results are promising.
This proposal presents experiences with measurement systems (including an integrated power-curve evaluation system for small wind turbines built by the author) that have been used during the last decade in local wind and hybrid (Wind-Diesel) isolated systems in South Patagonia, specially in Santa Cruz and Chubut provinces in Argentina and the XII Region of Magallanes in Chile. Most of these battery charging wind turbines are locally built by some of the small wind turbine manufacturers in Argentina. Also Wind resource assessment results with automatic loggers and some of the associated problems (specially harsh climate) are discussed. Some of the power, energy and wind measurement systems have operating since 1999 in the region, and their data has given an important insight regarding best practices for dimensioning criteria in local wind and climate regimes.
The more recent PWRC2 Small Wind Turbine – Power Curve Evaluation System (SWT-PCES) used at the INTI test site in Cutral-Có, Neuquén addresses the special requirements involved in power-curve measurement for small wind turbines, according to IEC 61400-12-1, Annex H. INTI seeks to become an accredited regional lab, and participates regularly of meetings organized by the Small Wind Association of Testers (SWAT) at IEA. Results from these campaigns have been shared within these meetings. The Cutral-Có systems were installed in mid 2012 and have been not only used to verify manufacturer power-curve claims for 6 models of wind turbines, but also have contributed to effective testing and manufacturing improvements on these models. The INTI initiative also contemplates a collective design and quality assessment effort, which has so far sponsored four manufacturer meetings in Argentina.