Investigation of resynchronisation process and its influence on microgrid components

摘要

One of the most challenging aspects regarding the control of microgrids is the reconnection with the bulk power system. During this process, high stresses can occur for the microgrid components, depending on the alignment of the voltages of the two systems. How deviations in frequency, amplitude and angle of the voltages, as well as a time delay in the switching of the control of the grid-forming generators in the microgrid to grid-feeding control affects these stresses is investigated in this work. Simulations are carried out in two real MV networks with power electronic-based and synchronous generators. It is shown that an angle deviation can strongly affect the stresses of synchronous generators, while delays in the switching of the control mode result in high loads for inverter-based generators. The results can be used to determine the dimensioning of generators in microgrids as well as the layout of the protection system.