Study Of Operational Characteristics And Protection And Control Equipment Closed-loop Test Platform Of Microgrid

Microgrid integrates micro-sources, energy storage devices, load, control and protection relays together to form a single controlled distribution network unit. Since the microgrid includes a large number of power electronic devices and complex control strategies, comprehensive understanding and grasp its operational and fault characteristics are the basis to ensure the normal operation of the microgrid.This article has built a digital microgrid simulation platform on Real Time Digital Simulator. It has realized the comprehensive and in-depth simulation and analysis in operating and controlling of distributed power and microgrid. Research contents and results are as follows:(1) This paper introduces the models of major equipments of the microgrid on Real Time Digital Simulator, such as typical models for distributed generation, including the model of constant speed constant frequency wind power system, doubly-fed VSCF, direct-drive permanent magnet VSCF, PV and micro-gas turbine model, flywheel energy storage model, battery energy storage model, super capacitor energy storage model. These models provide a solid foundation for simulation of microgrid.(2) In the depth analysis of the control strategy of microgrid, the overall simulation system of microgrid contains variety of DG is built in the RTDS platform. Then we research on the operational characteristics in the grid-connected mode and the isolated operation mode. The above microgrid simulation system is about to be used for the simulation work of the actual microgrid system,and has been extended to Sino-Singapore Tianjin Eco-city(SSTEC), proved the significance of this study.(3) On the basis of simulation model of microgrid,fault feature in microgrid and the impact of the microgrid accession on the traditional network is analyzed, when microgrid operating in stand-alone or grid-connected mode. Through the combination of real devices and simulation model, built a grid-connected protection and control equipment closed-loop test platform of microgrid. On the basis of the platform, simulate the input-output characteristic of microgrid and carry out the test for grid-connected protection and control equipment.