Overloading conditions management in remote networks by coupling neighboring microgrids

Abstract

Remote area microgrids (MG) can experience overloading or power deficiency throughout their dynamic operations due to load and generation uncertainties. Under such conditions, load-shedding is traditionally considered as the first successful mechanism to prevent system instability. To minimize load-shedding, islanded neighboring MGs can be connected to each other in remote areas to provide a self-healing capability. For this, extra generation capacity needs to be available in the distributed energy resources (DER) of one of the MGs to supply the extra demand in the other MG. In this way, the total load in the system of interconnected MGs will be shared by all the DERs within those MGs. This process falls within the network tertiary controller functions. Therefore, the tertiary controller should have a self-healing algorithm that needs to be carefully designed to initiate the command for interconnection of the MGs. The self-healing strategy needs to consider the required criteria to prevent system instability. The MGs will then be interconnected through an interconnecting static switch (ISS). This strategy also needs to decide when two interconnected MGs should be isolated. This paper focuses on the self-healing strategy, its criteria and features. The efficacy of the developed strategy in interconnecting and isolating the neighboring MGs is validated through PSCAD/EMTDC simulations.