| In modern power system, more and more power electronic devices are widely used, following by a variety of power quality problems. Including some steady-state problems such as harmonics, voltage three-phase unbalance, voltage fluctuation, which has long plagued by power quality staff. In recent years, short pulse,voltage fluctuation, oscillation transient,voltage swells and sudden drop which called transient power quality appeared in the power system more and more, causing a serious of economic losses. Therefore, in the face of the worsening of transient power quality problems,the staff is looking for some new ways to accurate monitoring, to control and governance ultimately become a recent focus of research of scholars from various countries.On the basis of analyzing the present situation of power quality monitoring at home and abroad, this paper analyzes the effect of three phase voltage unbalance, harmonics, voltage fluctuation and flicker, voltage deviation, frequency deviation and transient voltage on power quality. The system of power quality signal generator and monitoring system is developed based on Lab VIEW.This paper provides a power quality signal generator and detection platform. The two function blocks can be worked together, or can be used independently. By adjusting the signal frequency and amplitude, the output of signal generator can be set easily. Via data acquisition device, the output of signal generator is connected to the controlled equipment based on the individual applications. Based on disturbance detection platform, disturbance detection and the actual signal can be connected directly to Data Acquisition. By this way, the power disturbance can be detected without any delay.The monitoring system hardware design was completed by using NI PXI virtual instrument platform. Under the environment of NI LabView we designed and integrated all the algorithms in power quality disturbance analysis and detection, and also developed the soft power quality monitoring system based on PC resources. The tests showed some advantages such as results accuracy, user-friendly interface, stable performance, high reliability and scalability, etc. The method can reflect the power quality status of distribution network integrated and comprehensively, and provide scientific and accurate data support for improving the operation quality of power distribution network. |
