Enhancing inter-area steady-state stability margins with microgrids

This paper addresses the benefit of microgrids to enhance the inter-area steady-state stability margins. This is being achieved by means of frequency droop control of the microgrid. The latter is a small-scale energy system that can operate in island mode or in a grid-connected mode via converters while providing electricity and heat energy to a local load. We investigate the steady-state stability of a two-area 3 machine 9-bus system with and without microgrid. The microgrid is connected to a load bus and is provided with droop controls acting on the inverter. We showed that the gain of the frequency controller of the inverter changes the location of the system eigenvalues. With sufficient high gain, the eigenvalues move to the left-hand side of the complex plane, stabilizing the system.