近年来，电力负荷的构成出现了新的趋势，非线性、大功率冲击性及不对称性负荷的广泛使用对电网电能质量造成了不可忽视的影响，同时大批对电能质量非常敏感的新兴产业，如微电子、计算机、IT、数控自动化生产线等的迅速崛起，对暂态电能质量提出了更为苛刻的要求。要解决电能质量问题，就必须进行深入研究，对电网电能质量参数进行实时的监测。 本文首先介绍了电能质量的定义，并根据电力系统的运行状态和电能质量扰动现象的特点，将电能质量分为稳态和暂态两种，其中稳态电能质量以电压偏差、频率偏差、三相不平衡、谐波以及电压波动与闪变，暂态电能质量以电压暂升、电压暂降、短时电压中断作为本文的主要研究对象；对各项电能质量问题产生的原因、危害以及国家标准做了详细的分析说明，并在此基础上设计电能质量监测系统。 其次，由于FFT检测谐波时存在泄露和栅栏效应，本文采用加窗双峰插值修正算法来提高检测的准确度，并利用小波变换的奇异性检测原理实现对暂态扰动的识别和定位。同时，确定把小波变换和FFT相结合作为实现电网的稳态信号和暂态扰动信号检测的方法。该方法先利用小波分析的多分辨率特性对信号进行暂、稳态分离，然后对暂态信号进行扰动分析，对稳态信号进行谐波分析。 最后，结合虚拟仪器“软件就是仪器”的理念，利用LabVIEW强大的函数库和数据流编程能力，完成对电能质量指标进行监测的功能模块的设计，并采用MicroSoftwara Access数据库技术实现对监测和分析数据的存储、查询和删除。经实验室测试，本文所设计的监测系统精确度高，能够实现比较理想的电能质量监测。

In recent years, the power load that make up the emergence of new trends, the influence on power quality caused by non-linear, high-power impacting, unbalanced load can not be ignored. At the same time a large number of very sensitive to power quality emerging industries, such as micro-electronics, computer, IT, CNC automation production line, and etc.develop rapidly and bring forward a more rigorous request on transient power quality. In order to solve this problem, it is necessary to research on power quality in depth and monitor the power quality parameters in real time. First of all, introduces the definition of power quality, and according to the characteristics of power quality and the operating status of power system, power quality is divided into two kinds of steady-state and transient. The steady-state power quality includes voltage deviation, power frequency deviation, three-phase unbalance, voltage fluctuation and flicker, and harmonics; transient power quality includes voltage sags, swells and short voltage interruption as the main object of study. The cause, hazards and national standards of power quality problems have made a derailed analysis, and as the basis for the design of on-line power quality monitoring system. Then, for the problems of leak and fence effect due to FFT to the harmonic detection, Windowed Bimodal Interpolation Correction Algorithm was used in this paper to improve detection accuracy, and by using wavelet transformation of the singularity detection principle to achieve the disturbance of transient recognition and positioning. An effective method through combination of Wavelet Transform and FFT is putting forward. In this way, transient and steady-state signal are de-noised by wavelet method and segregated through Wavelet multi-resolution function firstly, then transient signal is analyzed in the disturbing surroundings and harmonic analysis uses the stead-state signal. Last, combined with the concept of virtual instrument “software is the instrument”, the outstanding developing platform of LabVIEW is used to the development of the functional module, for its flexible dataflow programming ability and abundant functions, and to adopt MicroSoftwara Access database technology for data storage, inquires and delete. Through laboratory testing, the design of the monitoring system has high precision and will be able to achieve the ideal power quality monitoring.