基于Hilbert变换的断路器选相合闸技术的研究

Research on phase selection technology of circuit breakers based on Hilbert transformation

针对塑壳断路器瞬动校验试验中的选相合闸,提出采用基于希尔伯特(Hilbert)变换的选相合闸技术,对其基本原理以及算法实现进行了分析与阐述,该方法能够动态的测量电网电压、电流的实际频率、相位以及功率因数角,较之传统的基于FFT的计算方法,参数计算精度对电网频率波动不敏感,且在幅值波动及较高信噪比下测试效果良好;通过对采样信号进行加窗预处理,进一步提高了选相合闸参数的计算精度。最终给出了基于PIC单片机的选相合闸装置的设计方案。

For the technology of phase selection of instantaneous calibration test for molded case circuit breaker,this paper proposes the technology of phase selection based on Hilbert transformation. The basic principle and algorithm implementation of it are analyzed,and this method can dynamically measure the practical frequency,phase and power factor angle of grid voltage and current. Compared with the traditional FFT calculation method,parameter calculation accuracy is not sensitive to the grid frequency fluctuation and the testing effect is good under amplitude fluctuation or high SNR condition. By adding-window pretreatment to the sampling signal,it further improves the calculation accuracy of phase selection parameters. Finally,it provides the design scheme of phase selection equipment based on PIC microcontroller.