The connection of offshore wind farms (OWFs) via diode rectifier-based- high-voltage direct current (DR-HVdc) transmission requires the use of wind turbine (WT) converters with grid-forming (GFM) capability. However, active and reactive power coupling and oscillation issues have been revealed in WTs employing reactive power frequency ( Q/f ) droop-based control schemes. This paper proposes a GFM control for OWFs based on remote active power regulation. The proposed scheme remotely regulates the active power of the DR-HVdc link by adjusting the dc voltage of the onshore modular multilevel converter (MMC). As a result, the voltages of offshore point of common coupling and WT converters are freed from being controlled for active power. On this basis, the WT converters can be equipped with classical GFM control schemes that incorporate active power frequency ( P/f ) and reactive power voltage ( Q/V ) droop relationships. The offshore frequency acts as an indication of the OWF active power balance and it is measured and transmitted to the onshore MMC through a communication channel to close the remote active power control. Comparative studies of power coupling characteristics and stability reveal that the proposed control scheme can achieve efficient decoupling control of active and reactive power in WT converters, prevent oscillation risks, and significantly enhance the system's stability. The feasibility and advantages of the proposed control scheme are verified through comparative time-domain simulations.

中文翻译：

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基于远程有功功率调节的二极管高压直流链路海上风电场并网控制

通过基于二极管整流器的高压直流（DR-HVdc）输电连接海上风电场（OWF）需要使用具有并网（GFM）能力的风力涡轮机（WT）变流器。然而，在采用无功功率频率的WT中已经暴露出有功和无功功率耦合和振荡问题（ Q/f ) 基于下垂的控制方案。本文提出了一种基于远程有功功率调节的 OWF GFM 控制。所提出的方案通过调节陆上模块化多电平变流器（MMC）的直流电压来远程调节DR-HVdc链路的有功功率。结果，公共耦合离岸点和小波变换器的电压不受有功功率的控制。在此基础上，WT变流器可以配备经典的GFM控制方案，其中包含有功功率频率（ P/f ) 和无功功率电压 ( Q/V ) 下垂关系。离岸频率作为 OWF 有功功率平衡的指示，对其进行测量并通过通信通道传输到陆上 MMC 以关闭远程有功功率控制。功率耦合特性和稳定性的对比研究表明，所提出的控制方案可以实现小波变换器中有功功率和无功功率的高效解耦控制，防止振荡风险，并显着增强系统的稳定性。通过比较时域仿真验证了所提出控制方案的可行性和优点。