Research On Multifunction Measurement And Control Device For Microgrid

In recent years, technology of distributed generation(DG) based on clean renewable energy has developed rapidly, due to the highlight of energy crisis and environmental problem. Microgrid is a new type of technology for the access of DG to power system. Microgrid effectively reduces the negative impact of DG on power system and meets the requirements of reliability and diversity on power supply. The formulation of microgrid energy management strategy, safe and stable operation of microgrid are based on a large number of real-time monitoring data. Measurement and control devices are installed where the main equipment of microgrid are connected to the grid, which can measure, control, model and communicate.In this paper, a multifunction measurement and control device for microgrid is designed. First, this paper proposes a layered microgrid comprehensive monitoring system, analyzes the role of multifunction measurement and control device in the monitoring system.Then, this paper analyzes the function and design of multifunction measurement and control device, secondly, introduces the hardware circuit design and software realization principle of multifunction measurement and control device. Finally, a microgrid experimental platform is set up, the function of the measurement and control device are verified. The research content of this paper mainly includes the following aspects:(1)Based on the research on the application of microgrid technology industry, the value of research on multifunction measurement and control device is analyzed, and the development status of multifunction measurement and control device for microgrid is reviewed.(2)A microgrid comprehensive monitoring system is proposed, including the multifunction measurement device, the micro grid central controller(MGCC), energy management system(EMS). The functions of measurement and control device are analyzed, including data acquisition and power quality analysis, protection and control, network communication and human-computer interaction(HCI).Also, hardware and software architecture of multifunction measurement and control device for microgrid are analyzed.(3)Hardware system architecture of multifunction measurement and control device for microgrid is proposed, including data analysis and processing system, measurement and control system, network communication system and HCI system.The circuit implementation of each hardware modules is analyzed. The CPU module adopts dual-core processor F28M35H52C from TI, including power supply module, reset circuit and JTAG interface. The memory module includes internal memory of processor and external extended memory SDRAM. The communication module includes Ethernet interface and serial communication interface. The analog signal acquisition module includes signal conversion module and AD converter, using the electric energy metering chip ADE7878. The HCI model is based on touch screen. The control module uses the optocoupler to isolate high voltage.(4)The software architecture of multifunction measurement and control device for microgrid is proposed, mainly including embedded real-time operating system (RTOS) and application software, and the double system debugging process is analyzed. The principle of realization of each software model is analyzed.In aspect of data acquisition and power quality analysis function, the specialty of the microgrid power quality is analyzed, the detection method of power quality is introduced, ADE7878 is adopted for data acquisition of electric power. In aspect of protection and control function, this paper analyzes how to select a fault protection, and a networked microgrid protection scheme is proposed. In aspect of network communication function, the principle of Ethernet communication and inter-processor communication (IPC) are introduced. In aspect of HCI function, the development process of software for touch screen and human-machine interface are analyzed.(5)Functional tests are implemented on multifunction measurement and control device for microgrid based on experimental platform. A microgrid experimental platform is built, the main experimental equipment and topology structure of experimental platform are introduced. In aspect of power quality analysis function test, the frequency measurement, voltage measurement, current measurement, harmonic measurement, three-phase imbalance measurement and flicker measurement are done. In aspect of protection and control function test, through the simulation of short circuit, the feasibility of microgrid network protection scheme based on communication is verified.In aspect of network communication function test, the device sends and receives data through Ethernet. In aspect of human-computer interaction function test, by measuring the bus voltage and current, the touch screen display normally.All the functional tests show that measurement and control device satisfies the requirement of the engineering application in microgrid.