基于Hilbert滤波器的无功功率计量算法研究

Research on Reactive Power Measurement Algorithm Based on Hilbert Filter

针对目前常用的计算无功功率的方法在谐波含量不断提高的情况下存在较大误差,采用基于Hilbert数字滤波器的无功功率计量算法,将电压的基波及各次谐波成份都移相-90°并保持幅值不变,采用有功功率计量方法来计量无功功率;分别采用最优设计法和半带滤波器法设计了FIR型和IIR型Hilbert数字滤波器,仿真得出相应的幅频和相频特性,并比较得出在含有24次谐波的电网环境下,两种类型的无功功率计量系统具有相似的计量精度,而FIR型滤波器具有更佳的相位均衡性。

Considering the problem of large error for commonly used reactive power calculation methods on the condi-tion of continuous harmonic content increase,this paper adopts the reactive power metering algorithms based on Hil-bert digital filter. The fundamental wave and harmonic components of the voltage are - 90＆#176; phase - shifted while their amplitudes are retained constant,and then the active power metering method is used to meter the reactive power. Mo-reover,the optimal design method and the half - band filter method are respectively used to design FIR and IIR Hil-bert digital filters. The corresponding amplitude and phase frequency characteristics are simulated. The result shows that in the grid environment containing 24 harmonics,the two types of reactive power metering systems have similar measurement accuracy,and the FIR filter can obtain better phase balance.