Steady-state Characteristics of a Series LCC HVDC System with Power Compensators for Wind Farms

A series line-commutated converter-based (LCC) high-voltage direct-current (HVDC) system using power compensators for wind farms has been proposed. In the system, a power compensator is connected to a receiving-end of the system in parallel which can compensate output ac power and can eliminate harmonic distortions of the output ac current. In this paper, steady-state characteristics of the series LCC-HVDC system having wind farms are investigated. Steady-state equations are derived first and a simulation model of the system is developed. The steady-state characteristics of the system are discussed through experimental and theoretical investigations. It is shown that even if input dc power is changed due to changes in wind speed, ac output active and reactive power supplied to receiving-end grid can be kept constant with the power compensator. Furthermore, it is shown that the harmonic distortions of the output current can be eliminated. Finally, the operating range of the system for changes in wind speed is discussed.