The main purpose of this paper is to present the grid requirements for the integration of wind farms into the Spanish Transmission System. In the particular case of voltage support capability, the Spanish Transmission System Operator (TSO), Red Electrica de Espana (REE) has defined a set of conditions to be met at the point of common coupling of a wind farm, not at terminals of a single wind turbine. A Verification, Validation, and Certification Procedure (VV&CP) to check compliance at terminals of a wind farm has been developed with the contribution and common agreement of all different wind power players and distribution system operators, leaded by the Spanish Wind Energy Association and supervised by REE. The VV&CP solves the problem defining a "Particular Procedure" based on testing or a "General Procedure" based on the simulation of the wind farm behaviour. It is the scope of Energy to Quality in this paper, to discuss and confirm the VV&CP reliability and validity, supported by field testing, validated models of wind turbines and simulation of wind farms. Conclusions are drawn on our efforts towards worldwide harmonization, on the development of a common VV&CP based on the Spanish and German experience.
