Steady-state performance analysis of an integrated wind turbine generating system in a DC transmission system with thyristor inverter

Steady-state performances of an integrated wind turbine generating system connected to a DC transmission system with an externally commutated thyristor inverter are discussed. The relationships between the DC transmission line voltage and the powers at the connecting points for the grids are revealed. It is shown that the operating range of the DC transmission line voltage, which is varied with fluctuations in the wind velocities, is determined by the power at the receiving-end grid. Then, we discuss DC power control methods to obtain maximum utilization from wind power and to compensate the fluctuation in the power at the receiving-end grid in the above-stated operating range. A comparative study of the DC power control by either the firing angle for the sending-end rectifier or the leading angle of the inverter is investigated. Finally, a combined DC power control method with the firing angle and the leading angle is explored.