POSITIVE URBAN INTEGRATION
The future of our buildings and intercity structures will require the integration of induction generators. These were often used for wind power projects in the 1980s and 1990s, and require reactive power for excitation so substations used in wind-power collection systems include substantial capacitor banks for power factor correction. Different types of wind turbine generators behave differently during transmission grid disturbances, so extensive modelling of the dynamic electromechanical characteristics of a new wind farm is required by transmission system operators to ensure predictable stable behavior during system faults. Induction generators support the system voltage during faults, unlike steam or hydro turbine-driven synchronous generators.
Today most turbines use variable speed generators combined with partial or full scale power converter between the turbine generator and the collector system, which generally have more desirable properties for grid interconnection and have Low voltage ride through-capabilities. Modern concepts use either doubly fed machines with partial-scale converters or squirrel-cage induction generators or synchronous generators (both permanently and electrically excited) with full scale converters. These will have a profound effect on the overall sustainability of intercity energy. Transmission systems operators will supply the intercity with a grid code to specify the requirements for interconnection to the transmission grid. This will include power factor, constancy of frequency and dynamic behavior of the wind turbines during a system fault.