摘要
本文关注模块化三电平静止无功补偿器因为并联台数变化引起的电网等效阻抗的变化,并据此提出了针对传统有源阻尼策略的改进策略。首先,建立了单台小信号等效模型,并从PCC处将单台等效模型拓展到多台并联模型。通过对谐振电流特性的分析,得出结论,在N台并联系统中,单台等效网侧阻抗扩大了N倍。同时分析了系统并联台数对谐振特性的影响,并提出了针对模块化三电平静止无功补偿器的新型有源阻尼策略。最后,通过实验研究,验证多台并联系统建模和谐振特性分析的正确性,所提出的新型有源谐振阻尼策略能够很好地抑制并联系统谐振。
In this paper,the variation of equivalent impedance of grid due to shunt number of modular three level static var compensator is concerned and,on this basis,the improvement strategy to the traditional active damping strategy is proposed.Firstly,single unit small signal equivalent model is set up in this paper,and it is expanded to multiple units of shunt models from PCC.It is concluded from the analysis of the feature of resonance current that in the N units of shunt system the equivalent grid side impedance of single unit is expanded N times.At the same time,the influence of shunt unit numbers of the system on the resonance feature is analyzed and the new active damping strategy of modular three level static var compensator is proposed.Finally,the correctness of the modeling and resonance feature analysis for the multiple units of shunt system is verified by the experimental study and that the proposed new active resonance damping strategy can suppress effectively the resonance of the shunt system.
引文
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