Reliability and Resilience Analysis and Comparison of Off-Grid Microgrids

The desire of achieving good reliability and resilience levels in power grid design procedure, has given a central role to the study of off-grid microgrids as feeding alternative in case of catastrophic weather conditions. These phenomena, characterized by a High Impact with Low Probability of occurrence (HILP), can result in disastrous effects on power system assets, e.g., distribution lines and towers. This paper proposes a probabilistic resilience assessment technique based on a Sequential Monte Carlo, Optimal Power Flow simulation in order to study the economic and the energetic feasibility of off-grid microgrids in case climatic event create blackout on the network. Generally, the reliability considerations on the electrical network are made using average probability values of outage occurrence and they do not consider the effect of HILP. In order to overcome this issue, a Conditional Value at Risk simulation is proposed and the response of the network to catastrophic phenomena is studied. Considering as test network the bus 2 of the Reliability Test System (RBTS) firstly introduced by Roy Billinton in 1997, a CHP based microgrid and a PV+BESS+DG microgrid are compared in order to understand which technology is more resilient in case of HILP. As key outputs, the results have shown the strong relation between the Reliability of the network and the location of the source of energy and have demonstrated that if the interest is to increase the response of the network to HILP phenomena, is better to operate the grid providing energy with the CHP microgrid.