对 O.Chaari的复值小波进行了改进 ,提出了一种新型的半复小波 ,推导了半复小波的单向递推算法 ,从而提高了电力系统故障诊断的实时性 ;采用改进的半复小波对电力系统中各种典型的扰动信号进行了分析。仿真分析表明基于半复小波的电力系统故障实时检测方法 ,灵敏度高 ,具有很强的实时性 ,因而在提高电力系统的运行水平和供电质量方面 ,具有显著的社会经济效益 This paper improves O.Chaari’s complex-valued wavelet, proposes a new type of half-complex wavelet, and deduces one-way recursive algorithm of half-complex wavelet to improve the real-time performance of power system fault diagnosis. Wavelet analysis of various typical disturbance signals in power system. Simulation results show that the real-time detection method of power system fault based on semi-complex wavelet has high sensitivity and real-time performance, and thus has significant social and economic benefits in improving the operation level and power supply quality of power system