采用电阻链滤波的变压器过励磁谐波抑制方法

为解决负荷低谷时段、电压偏高情况下变电站谐波指标超出国家标准问题，由变压器铁芯的励磁原理出发分析谐波的产生机理；利用PSCAD平台上搭建的变电站仿真模型，得到不同额定磁密、工作电压、电网阻抗特性下的5、7次谐波含有率变化特性；提出利用单调谐滤波器过滤变压器产生的主要谐波分量，通过电阻阻尼特性消除滤波器谐振现象的变压器过励磁谐波抑制方法。YNd11和Dyn11 2种类型的变压器谐波抑制效果仿真分析结果表明，带电阻链的单调滤波器组能有效抑制变压器产生的5、7次谐波分量，抑制后的总谐波含量降至国家标准允许范围内，滤波方法有效。

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In order to solve the problem that the harmonic index of the substation exceeds the limit of the national standard at low load and high voltage,a method for suppressing over excitation harmonics of transformers based on single tuned filtering of resistor chains is proposed,using a single tuned filter to filter the main harmonic components and damping properties through resistors to eliminate filter resonance,based on analysis of the generation mechanism of the harmonic by the excitation principle of the transformer core and characteristics of the 5th and 7th harmonic content ratios with rated magnetic densities,working voltages and grid impedances using the simulated substation model on the PSCAD platform.Harmonic suppression effect is simulated and analyzed on PSCAD platform with transformers of YNd11 and Dyn11.The results show that the installation of a single tuned filter bank with a resistor chain can effectively suppress the 5th and 7th harmonic components generated by the transformer,and the suppressedl harmonic content is reduced within the allowable range of the national standard.The method has proved effective.