谐波监测式电气火灾监控系统设计

Design of harmonic monitoring electric fire monitoring system

针对传统设备大多无法检测电气线路中性线电流谐波的问题,设计三相四线制谐波监测式电气火灾监控系统。采用加汉宁窗插值处理的快速傅里叶变换算法分析谐波成分,构建基于主控芯片树莓派+三相计量芯片RN8302B+监测报警模块的系统架构。RN8302B通过串行外设接口向树莓派提供包含中性线电流在内的四组电流采样缓存数据,设计基于时域抽取法的快速傅里叶变换(DIT-FFT)和监测报警程序。利用LabVIEW仿真软件构造谐波源进行算法验证分析,再结合实物测试,结果表明:监控系统可以实现对中性线的谐波电流分析,加窗插值算法可以有效减少截断带来的FFT频谱泄漏,谐波电流检测精度高,系统报警响应速度快。

In order to solve the problem of current harmonics on neutral line which can not be detected by traditional equipment,a three-phase four-wire harmonic monitoring electric fire monitoring system is designed.The harmonic components are analyzed by a fast Fourier transform(FFT)algorithm with Hanning window interpolation,and a system architecture based on the main control chip Raspberry Pi and three-phase metering chip RN8302B with monitoring and alarm module is constructed.RN8302B provides four sets of current sampling buffer data including neutral line to Raspberry Pi through serial peripheral interface,and a decimation in time fast Fourier transform(DIT-FFT)and the monitoring alarm program are designed.The LabVIEW simulation software is used to construct the harmonic source for the algorithm verification analysis.Combined with the physical experiment test,the results show that the monitoring system can realize the harmonic current analysis on the neutral line,the window interpolation algorithm can effectively reduce the FFT spectrum leakage caused by truncation,and the detection accuracy of harmonic current is high.