多直流馈入背景下江苏电网的直流换相失败问题评估及动态无功协调控制方法

Evaluation of DC Commutation Failures and Dynamic Reactive Power Coordination Control Method in Jiangsu Power Grid with Multi-Infeed DC Systems

在以新能源和直流馈入为主的新型受端电网中,常规直流换相失败问题常威胁着系统的安全运行。为此,归纳和提出了三项用于评估直流换相失败问题严重程度的指标,并以江苏电网为例分析了直流换相失败严重程度。然后,针对严重换相失败问题,提出了一种用于加强直流系统恢复能力的动态无功协调控制方法。该方法先根据潮流控制目标确定系统运行边界和柔性直流换流站等设备出力,再基于电压交互因子筛选出与目标直流系统强相关的动态无功源,进而通过动态无功协调控制策略加强目标直流系统换相失败后的恢复能力。最后,在江苏电网实际算例中进行了测试,验证了所提动态无功协调控制方法的有效性。

The safe operation of new receiving-end power grids that rely heavily on renewable energy and DC systems is often threatened by commutation failures within the DC systems.Therefore,three indicators used to evaluate the severity of these commutation failures are summarized and proposed in this study.For illustrative purposes,the severity of the DC commutation failures in the Jiangsu Power Grid are analyzed based on these parameters.Subsequently,a reactive power coordination control method is proposed to enhance the DC recovery ability in response to serious commutation failures.The following is an outline of the phases involved in our study.First,the operating state of the system and the output of some devices,such as MMC-DC converters,were obtained by considering the power flow control objectives.Second,dynamic reactive power sources strongly related to the concerned DC systems were identified based on voltage interaction factors.Third,the dynamic reactive power coordination control method was employed to enhance the recovery ability of the DC systems.Finally,the effectiveness of the proposed coordination control method was verified in a case study of the Jiangsu Power Grid.