Stability and eigenanalysis of a sustainable remote area microgrid with a transforming structure

Electrification of remote and rural areas is usually in the form of a standalone power system that operates self-sufficiently. Renewable energy resources, if available in such areas, are expected to have a large and ultimately, a full share of electricity generation in these areas to lessen the levelized cost of electricity for the operators. Thereby, the electric network of such remote areas can be considered as a sustainable microgrid (MG). Larger remote areas can be supplied by several MGs, each with a different operator (owner) and running independently. The occasional power deficiency and overloading of those MGs can be addressed by local support from the floating energy storages, or by importing power from a neighboring MG, after interconnecting the MGs temporarily. Thus, such MGs are expected to experience a transformation in their structure; a small change when new energy storage systems are connected and a significant alteration when it is coupled with another MG. Before such actions, the stability of the new system is vital to be cautiously examined to intercept the transformation, if instability is to occur. An eigenanalysis-based small signal stability evaluation technique is used in this research for an MG with a transforming structure. The analysis will be used as a decision-making process prior to a change in the MG. If the new system is defined to be unstable, the analysis can provide a range of control parameters for the energy resources to guarantee the stability of the new system. Through MATLAB-based analyses, the impact of the number and rating of the sources and loads, as well as the system topology of one MG on the stability of the system of coupled MGs, is evaluated. Moreover, the impacts of the number, energy capacity, rate of discharge and state of charge of the energy storage systems are assessed.