Abstract: The power quality network monitoring system based on virtual instruments is a network virtual instrument system that combines network technology with virtual instruments. This paper introduces the network structure of the system, the overall design of the virtual instruments, discusses the software design for monitoring some power quality parameters, and finally discusses the method for realizing remote monitoring. Keywords: virtual instrument; network; database; remote monitoring [align=center][b]Realization of Power Quality Network Monitoring System Based on Virtual Instrument Wei Pei-yu Li Zhen-mei[/b][/align] Abstract: The power quality network monitoring system is based on virtual instrument, combining network technology and virtual instrument with a network virtual instrument system. This paper introduces the network construction of the system, the general design of the virtual instrument, the software design of monitoring some parameters, and presents an approach to realizing remote monitoring. Key words: virtual instrument; Network, database; remote monitoring The penetration of computer hardware and software has brought a new revolution to traditional testing technology. Supported by the continuous progress of computer, microelectronics, sensor, communication, and network technologies, and stimulated by the research needs of multiple fields, it clearly demonstrates deep integration with high technology. Combining network technology with virtual instruments to form a network virtual instrument system is the direction of virtual instrument system development. This paper introduces the system's network structure, functions, and the overall design of the virtual instrument, discusses the software design for monitoring some power quality parameters, and finally discusses the method for realizing remote monitoring. 1. System Network Structure and Functions This system adopts a client/server model to establish a computer network. Clients are connected to the server via network cards and cables to achieve network resource sharing. The system structure is shown in Figure 1. The front end consists of PCs forming virtual instruments, while the back end is the server. The virtual instruments are mainly used for real-time monitoring, displaying waveforms of three-phase voltage and current. After analysis and calculation, parameters such as system frequency, total harmonic distortion rate, and three-phase voltage imbalance are displayed. When any indicator exceeds the standard, the system will alarm. The collected raw data and analyzed data are written to a remote database server via the computer network. The server side uses a large database for data storage and management, and can analyze and process measurement results. It can not only observe real-time data from each test point (using ADO technology in LabVIEW software to access the large database and reproduce the virtual instrument panels of each test point), but also query historical data from each test point. It can analyze and summarize power quality data from each test point, generating daily and annual power quality reports, and manage the entire measurement network. The key technologies used in the system are described below. For details, please click: Implementation of a Power Quality Network Monitoring System Based on Virtual Instruments