Design Of Real-time Power Quality Monitoring System For Grid Connected Inverter

With the rapid development of modern social economy, energy demand and consumption is increasing. Traditional fossil energy almost has been consumed. In order to solve this energy problem, more and more countries in the world are developing renewable energy and new energy as a new way to solve the energy problem. With renewable energy and clean source exploited, for the foundation of distributed generation has got rapid development. But within the process of distribution system with distributed generators appeared a series of power quality problems. Have a great threat to the safe operation of power grid, it is necessary to monitor the power quality of distribution power in real time, so as to ensure the security of power network operation.On the basis of consulting relevant literature, combining with the research status of power quality at home and abroad, based on the characteristics of distributed generation system, the power quality of the national standard, analysis and detection methods were deeply studied. And according to the characteristics of grid inverter output power quality research developed a set of power quality monitoring system based on Lab VIEW. The system adopts a data parallel processing structure, the basic parameters of electrical energy quality, steady power quality and transient power quality detection and analysis of data storage and processing, and can be remote real-time monitoring of power station operation.Compared with the traditional power quality detection system, the hardware is the core of the system, the system has great advantages in real-time and scalability, and the detection parameters are more comprehensive.This paper studies the power quality monitoring system mainly includes the following modules, data acquisition module, steady state power quality monitoring module, transient power quality monitoring module, data storage module, network communication module of several parts. The steady-state power quality detection module mainly completes the voltage deviation, frequency deviation, three-phase unbalance, harmonic, Detection of the voltage fluctuation and flicker. Transient power quality detection module uses the method of mixed programming with MATLAB to build the program, mainly to complete the detection and analysis of voltage sag, voltage sag, voltage interruption, voltage transient four parts. The data storage module uses its own ADO interface to connect with the database, and realize the data storage and reading, The module of network communication protocol using TCP program to build and complete the data receiving and transmitting.Finally, this paper uses Lab VIEW to build the signal generator, Generate signal of voltage and current of each part of the system for simulation and testing, Experimental results show that the system is the successful implementation of the multi-channel parallel processing, high accuracy of the test result, good real-time performance, various electric energy measurement results meet the national standard requirements, effect is ideal, to achieve the desired objectives and requirements, with a good prospect of application.