The purpose of the thesis was to study on-grid system for a small 2 kW wind tur-bine. The control system was made of Vacon NXI frequency converters. The elec-trical model of the wind turbine studied was developed in the Technobothnia la-boratory. The aim of the thesis was to gather knowledge about the usability of the Vacon on-grid system in small wind turbine use and start development of the test-ing system.

Materials used in the thesis were mostly Vacon application manuals but also re-searches on wind power technology and control of wind turbines were used. The possibility of controlling frequency converters with an external programmable logic controller was applied in the laboratory tests. A squirrel cage motor con-trolled by NXP frequency converter was used in the simulation of the wind tur-bine. The process data controls and measured values used in the simulation were connected to a supervising system developed in the laboratory. A Profibus cable was used in the data transfer between the PLC and frequency converters.

As a result, electrical power was fed to the grid and performance tests for the sys-tem were made. The conclusion of the thesis was that Vacon on-grid system is suitable for small wind turbine use when all the protections and controls de-manded by the grid owner are appropriate.