基于等效无功弹性的变换器电压支撑能力评估

Evaluation of voltage support capability of transformers based on equivalent reactive power elasticity

针对现有电压支撑能力评估方法鲜有关注变换器控制动态和无功扰动期间电压变化速率,难以准确评估不同控制方式下变换器的电压支撑能力及其在快速扰动场景下的适用性,提出了一种基于等效无功弹性的变换器电压支撑能力评估方法.首先计及变换器控制策略,分别构建典型构网型和跟网型变换器的幅值运动方程.然后,基于幅值运动方程,提取了与电压变化速率关联的等效无功弹性JQ作为电压支撑能力的评估指标;通过分析JQ的幅频特性,对比评估了两类变换器在无功快速波动下的电压支撑能力及相关差异.最后,在Matlab/Simulink中搭建仿真模型,验证了分析的准确性.

A voltage support capability evaluation method based on equivalent reactive power elasticity was proposed to accurately evaluate the voltage support capability of converters under different control modes and their applicability in fast disturbance scenarios,as existing voltage support capability evaluation methods rarely focus on the dynamic control of converters and the rate of voltage change during reactive power disturbances.Firstly,considering the control strategy of the converter,the amplitude motion equations of typical grid-forming and grid-following converters were constructed separately.Then,based on the amplitude motion equation,the equivalent reactive power elasticity JQ associated with voltage change rate was extracted as an evaluation index for voltage support capability.By analyzing the amplitude frequency characteristics of JQ,the voltage support capability and related differences of two types of converters under rapid reactive power disturbance were compared and evaluated.Finally,a simulation model in Matlab/Simulink was built to verify the accuracy of the relevant analysis.