DC Microgrid Load Shedding Schemes

This paper investigates and compares the performances of three different load shedding schemes in a direct current (DC) microgrid. Comprehensive time-domain simulation studies are conducted on a realistic DC microgrid study system using the PSCAD/EMTDC software. The study results indicate that (i) application of both voltage-based and timer-based load shedding schemes necessitates making a compromise between the voltage regulation performance and the power supply reliability, (ii) the voltage-based load shedding scheme may cause the critical loads to experience large and prolonged voltage sags (iii) the timer-based load shedding scheme may cause over-shedding of loads, which degrades the power supply reliability, and (iv) the combined load shedding scheme resolves the voltage sag issues of the voltage-based and timer-based schemes and also prevents over-shedding.