Development of a Self-Healing Strategy to Enhance the Overloading Resilience of Islanded Microgrids

Abstract

This paper proposes a self-healing strategy for two neighboring islanded microgrids (MGs) that are connected together through a normally open interconnecting static switch (ISS). Each MG is expected to support the other during power deficiencies, which is facilitated by the developed self-healing agent. This agent operates based on either a centralized approach, when data communication system is available, or a decentralized approach, when data communication system does not exist or is temporarily unavailable. The necessity and possibility of the MGs interconnection or isolation is determined based on instantaneous power generation of the distributed energy resources in both MGs (in the centralized approach) and local frequency measurements at either side of ISS (in the decentralized approach). The dynamic performance of the MGs with the proposed strategies is evaluated by PSCAD simulation studies. Furthermore, the stability of the system of coupled MGs is investigated through small-signal stability and modal analyses in MATLAB.

A Two-Layer Distributed Cooperative Control Method for Islanded Networked Microgrid Systems

“…Thus, the three-level control architecture of MGs can be modified to fit the NMG system [13]- [15]. The two-layer architecture adds an extra NMG-control layer and considers the three-level control of MGs as the MG-control layer to form a two-layer architecture [16]- [29]. The two-layer architecture is inspired by the multi-layer and multi-area control concept in the bulk power system [30].…”

“…(20) where ω and p are positive control gains. Equation (19) is (16) with an additional quaternary control variable Ω . MG is generated as the frequency reference of (9).…”

A multilayer optimization scheme to retain the voltage and frequency in standalone microgrids

“…As an example, [7] proposes a probabilistic approach to optimally select the droop coefficients of DDGs while [8] proposes a method to combine the secondary controller of the MG with the primary controller of DDGs to solve the optimal power sharing problem by only focusing on minimizing the fuel cost and voltage variation. Another scheme is proposed in [9] which has also considered the power loss of the MG. Alternatively, control of BESs, demand response (DR) loadshedding (LS) and renewable curtailment (RC) has been separately used in [10][11][12][13] to resolve the VF violation problems in an MG. Alternatively, reconfiguration of the MG network is considered as a cost-effective technique in [14][15] while the possibility of eliminating the VF problem through an external entity (EE) such as a neighboring MG has been proposed in [16][17][18][19]. Many studies have focused on the optimal design of MGs at their planning stage while limited works such as [8][9] have focused on their short-term operational stage.…”

Power transaction management amongst coupled microgrids in remote areas

“…Recently, the concept of coupled MGs (CMGs) has been proposed in which two or more neighboring MGs of a remote area can interconnect provisionally to support each other during emergencies; e.g., when a fault occurs in a section of an MG, leading to the outage of one or some of its DERs, or when an MG is overloaded, or when an MG experiences excessive generation from its renewable energy-based non-dispatchable DERs (NDDs), or during normal conditions to minimize the levelized cost of electricity [5][6][7]. Let us consider the network of Fig.…”

“…Ref. [7] presents the conditions based on which the overloading of a PMG and the availability of excess power in the neighboring HMG can be detected. Ref.…”