Direct interconnection of offshore electricity generators

Stringent grid codes imposed by transmission system operators (TSOs) have led wind turbine manufacturers to overdesign their products. As an individual power generator, each single wind turbine has to meet those regulations. However, in a “farm” like configuration, a different approach can be taken. This paper describes how renewable energy generator units can be simplified in order to bring manufacturing and maintenance costs down and increase reliability. Synchronisation challenges were addressed using special control algorithms to overcome issues not present in the case of synchronising generators having controllable prime movers (diesel engine, turbines etc.). In the case of wind turbines, the wind is the prime mover and is not controllable. A brief description of a prototype is given and data has been extracted from the rig as well as from modelling.

Research highlights
► 3 permanent magnet generators connected in parallel simulating a wind farm.
► A system control and data acquisition facilitate the synchronisation.
► Generators connected to a local bus without power converters.
► Synchronisation and energy transfer managed by several algorithms.
►  Results from analysis proves that generators do not need converters in-situ.