Grid code interrelation, wind generation evolution and reactive compensation, special topics inside a grid code

Abstract

By all appearances, the evolution of wind generation has been orientated to satisfy the requirements, every time inside narrower limits, imposed by the grid codes, standing out among all the determining ones, the administration of the reactive power. In the age of induction generator's fixed speed, the requirements to access to the network were lax, considering the lack, for any practical, end of the capability's curves. The advent of the DFIG's and the electronic switch (IGBT's) evolution, have allowed that a wind farm, in the first instance, can handle the reactive power by means of the availability of a capability curve and comply, this way, with the most restricted codes. The update has been given in very recent date, with a wind farm's activation of an integrated by DFIG's and full converter generators, whose capability's curve are similar to that of a conventional plant. Seeing to the future, probably let's be able attend the elimination of the gear's box. Nowadays the wind generators operate better with high speeds and, therefore, they need gear's box to reduce it. Considering all gear train's issues: cost, vibrations, noise, fatigue, lubrication and maintenance, eliminating the box would have big advantages. The recent versions of the grid code, authorizes the operator to treat the wind farm just like a conventional plant, using the capacity of reactive power inside the extended range of the capability curve. This is not just for reducing the limits inside which one must move the tension and the power factor; now the wind farms must satisfy polygon's critical points of operation, impossible to satisfy with the first generation machines. Under this new operation criterion, the good administration of reactive power is the result from a combination of machines contributions, switched capacitor banks and the reactive dynamic compensation get it using switch electronic devices. The grid code tacitly, yields the owner of the wind farm, the responsibility of solving extraordinary problems or out of the normal catalogue, like a subsynchronous resonance or torsional effects. Give an idea of the entail of all these factors is the purpose of this paper. (4 pages)