过电压监测中电网频率微变检测方法

提出将互相关检测和混沌理论相结合应用于过电压监测中的频率跟踪,检测相对于中心频率极小的微弱信号.分析了Duffing方程在从混沌状态到大周期转变时表现出的良好的等Q共振频率特性,阐述了混沌相平面变化检测弱信号的基本原理.算例结果表明该方法具有较低的信噪比工作门限,测量噪声得到抑制,测量频率误差小等优点,通过仿真计算给出了Duffing混沌谐振子的临界值以及针对不同信噪比和信号情况所得到的检测结果,实现了对系统频率的准确检测,保障了过电压监测系统的同步采样.

Grid Frequency Micro-Variation Detection Method in Overvoltage Monitoring

The method which combines cross correlation detection with chaos theory to detect the weak signals relative to central frequency in overvoltage monitoring is proposed in the paper. The nonlinear Duffing equation shaves better equivalent Q resonant frequency locking property when system transits from chaotic to great periodic motion. The case indicates that the method has lower SNR threshold and small measuring error, and could control the measuring noise. The simulation gives the critical value of Duffing simple oscillator and detection results facing to different SNR and signals. The method realizes correct detection of system frequency and it secures the synchronized sample in over voltage inspecting system.