Asynchronous grid interconnection using brushless Doubly Fed Induction Machines: Assessment on various configurations

Electric power systems are commonly interconnected for cost effiective robust delivery purposes. Transmission interconnection benefits from load diversity, variety of sources and fuel prices. In addition; nation-level grid interconnection offers increased reliability, reduction of power interruption and generation-cost minimization. Various techniques are applicable for grid interconnection like High Voltage Direct Current links (HVDC), Variable Frequency Transformer (VFT) and Doubly Fed Induction Machine (DFIM). The development in machine construction enhances their capability. Various DFIMs are currently available such as the brushless twin stator cascaded doubly fed induction machines (BTDFIM) and the single frame brushless doubly fed induction machine (BDFIM). This paper discusses the application of grid interconnection using various doubly fed induction machines illustrating machine construction, operation and limitations.