背靠背直流互联系统主动频率响应控制策略

An Active Frequency Response Control Strategy for Back-to-back DC Interconnection System

相较于交流同步互联电网,低快速频率响应能力的直流异步互联电网频率稳定形势更为严峻。基于主动频率响应控制思想及其框架,提出大功率缺失下的背靠背直流互联系统主动频率响应控制策略。建立了背靠背直流互联系统网络结构模型及背靠背换流站控制系统模型,计及扰动后背靠背直流互联系统及频率响应动态特性,提出了一种基于模型预测算法的主动频率响应控制策略:频率下降阶段迅速调节非同步电网间直流传输功率;频率恢复阶段平抑和缓解频率振荡。算例分析表明:所提出的主动频率响应控制策略能够充分发挥背靠背直流互联系统调频能力,提高非同步电网间的频率响应支援能力。

Compared with AC synchronous interconnected power grids,the frequency stability of DC asynchronous interconnected power grids with low inertia and low frequency response capability is more severe.Based on the idea and framework of active frequency response control,an active control strategy for back-to-back DC interconnected power grids under high power loss is proposed.The network structure model of back-to-back DC interconnection system and the control system model of the back-to-back converter station are established.The dynamic characteristics of the back-to-back DC interconnection system and the frequency response after the disturbance are taken into account,and an active control strategy based on the model prediction algorithm is proposed as follows:in the frequency drop phase,the DC transmission power between non-synchronous grids is quickly regulated;in the frequency recovery phase,the frequency oscillation is smoothed and alleviated.The analysis of the calculation example shows that the proposed active control strategy can give full play to the frequency modulation ability of the back-to-back DC interconnection system,and improve the frequency response support capability between asynchronous power grids.