The International Electrotechnical Commission (IEC), an organization that prepares and publishes international standards for electrical, electronic and related technologies based in Geneva, has published the second edition of its standard for measuring the power quality of wind turbines.
Developed by IEC Technical Committee 88, IEC 61400-21 sets out the tests that can be used to compare both wind turbines of different types or makes and different electricity grid requirements. The latter are complex, as they typically consider the capability of a wind farm rather than that of a single wind turbine.
Modern wind farms may control the reactive power or voltage just like any other power plant and may also control active power or frequency, as long as wind conditions permit. Therefore, connecting modern wind power plants to the grid presents very similar challenges to those of connecting any other power plant, according to the report.
Different wind turbine types have different power quality characteristics. IEC 61400-21 provides a uniform methodology to ensure consistency and accuracy in the presentation, testing and assessment of power quality characteristics of grid-connected wind turbines. The power quality characteristics described in the IEC standard include wind turbine specifications, voltage quality (emissions of flicker and harmonics), voltage drop response, power control (control of active and reactive power), grid protection and reconnection time.
SOURCE: International Electrotechnical Commission
