基于谐波阻抗匹配的微电网互联线路谐振分析及抑制措施

相邻微电网之间往往通过长距离的输电线路互联.针对这类输电线路双端存在独立谐波源的系统,其谐波交互特性与谐波放大机理更为复杂,采用传统阻性有源电力滤波器方法抑制谐振并不适用.文中基于传输线理论分析互联线路的谐波传播机理,并提出基于谐波阻抗匹配的谐振抑制方案.为了克服线路参数与谐波源相角信息的不确定性,提出基于线路中点谐波电压检测的有源电力滤波器谐波阻抗协调控制策略,根据谐波电压含量在线调节线路两端谐波阻抗相角,实现谐振抑制目标.与此同时,提出一种有源电力滤波器改进控制策略,保证其谐波阻抗相角可以任意调节.仿真验证了控制策略的有效性.

Analysis and Suppression Measures for Resonance on Interconnection Line Between Mircogrids Based on Harmonic Impedance Matching

Neighboring microgrids are usually interconnected by long transmission lines. For the system where both sending and receiving ends of transmission lines have independent harmonic sources, the harmonic interaction characteristic and the harmonic amplification mechanism are more complicated, and the conventional resonance suppression method of resistive active power filter is not suitable. Based on the transmission line theory, this paper analyzes the harmonic propagation mechanism of interconnected lines, and proposes a resonance suppression method based on harmonic impedance matching. To overcome the uncertainty of line parameters and phase angle information of harmonic sources, this paper proposes a coordinated control method for harmonic impedances of active power filters based on the line middle-point harmonic voltage detection. According to the harmonic voltage content, the phase angles of harmonic impedance at both ends of the line are adjusted online to realize resonance suppression. Meanwhile, an improved control strategy of active power filters is proposed to ensure that the harmonic impedance phase angle can be adjusted arbitrarily. Simulation results verify the effectiveness of the proposed scheme.