SVC附加闭锁控制提高双馈风电场高电压穿越研究

Additional locking control of SVC improving high voltage ride through of DFIG based wind farm

为缓解风机高电压脱网对电网安全稳定运行造成的严重威胁,文中解析了集群风电基地广泛应用的静止无功补偿器(SVC)引发电压过冲的机理。SVC响应滞后及其自身物理特性缺陷,使其在电压跌落时难以提供有效容性无功支撑,而在电压恢复期向系统输出冗余容性无功。为克服SVC控制性能的这种局限性,提出一种SVC附加闭锁控制策略,主要适用于外部故障引起SVC接入点出现严重低电压的场景。该控制策略给出SVC闭锁判定条件及闭锁后SVC重新投入条件,避免"错位补偿",有效降低SVC引发非故障风机并网点高电压的威胁,保障风场安全稳定运行。最后仿真验证了所提控制策略的有效性,并对后期风电场的建设与运行提出指导性建议。

For the sake of easing the threat to the safe and stable operation of power system, control performance of static var compensator, widely used in cluster wind farms, and their triggering process of voltage overshoot are analyzed detailedly in this paper. The combined action of response lag and physical property defects, produces malposition compensation effect in SVC, which supports no effective reactive power output during voltage drip, while exports surplus reactive power during recovery process after fault resection. In order to overcome the limitations of SVC control performance, an additional locking control embedded in the SVC controller, is put forward, which comes into action merely under the condition of lower voltage.The judging criteria of SVC locking control and reoperating after shutting is given, to avoid malposition compensation, to effectively reduce high voltage threat triggered by SVC, thus ensuring the safety and stability of wind farm. Lastly, simulation has verified the effectiveness of the proposed control strategy. In addition, this tip offers some guidance for late construction and operation of wind farm.