Steady-State Security Region Calculation for a Multi-Energy Microgrid

Maintaining operational security is an essential requirement for a multi-energy microgrid (MEMG). This paper proposes a method for calculating the steady-state security region (SR) for the MEMG. Firstly, the steady-state model and security constraints for a MEMG are constructed. From the perspective of multi-energy supply capability, the SR is defined as a set of all system states (multi-energy loads) that satisfy security requirements, which is enclosed by several security boundaries. Then, indicators of the volume (area), security distance and critical distance of the SR are adopted to measure the energy supply adequacy and security margin of the MEMG. Finally, based on the proposed SR, security assessment for the MEMG under both grid-connected mode and islanded mode is conducted in case studies, where the impact of changes of load and photovoltaic (PV) output is also analyzed. The results verify the effectiveness of the proposed SR for MEMG.