Distributed energy storage (DES) plays an important role in microgrid operation and control, as it can potentially improve local reliability and resilience, reduce operation cost, and mitigate challenges caused by high penetration renewable generation. However, to ensure an acceptable economic and technical performance, DES must be optimally sized and placed. This paper reviews the existing DES sizing methods for microgrid applications and presents a generic sizing method that enables microgrid planners to efficiently determine the optimal DES size, technology, and location. The proposed method takes into consideration the impact of DES operation on its lifetime to enhance the obtained results accuracy and practicality. The presented model can be used for both grid-tied (considering both grid-connected and islanded modes) and isolated microgrids.

Distribution network operators and planners face a significant challenge in optimizing planning and scheduling strategies to enhance distribution network efficiency. Using improved particle swarm optimization (IPSO), this paper presents an effective method for improving distribution system performance by concurrently deploying remote-controlled sectionalized switches, distributed generation (DG), and optimal network reconfiguration. The proposed optimization problem’s main objectives are to reduce switch costs, maximize reliability, reduce power losses, and enhance voltage profiles. An analytical reliability evaluation is proposed for DG-enhanced reconfigurable distribution systems, considering both switching-only and repairs and switching interruptions. The problem is formulated in the form of a mixed integer nonlinear programming problem, which is known as an NP-hard problem. To solve the problem effectively while improving conventional particle swarm optimization (PSO) exploration and exploitation capabilities, a novel chaotic inertia weight and crossover operation mechanism is developed here. It is demonstrated that IPSO can be applied to both single- and multi-objective optimization problems, where distribution systems’ optimization strategies are considered sequentially and simultaneously. Furthermore, IPSO’s effectiveness is validated and evaluated against well-known state-of-the-art metaheuristic techniques for optimizing IEEE 69-node distribution systems.

The sub-synchronous oscillation (SSO) phenomenon presents a significant risk to the overall safety and stability of power networks, as evidenced by numerous real-world incidents. This paper introduces a novel approach to mitigating SSO in series-compensated transmission lines by employing a resonant controller in conjunction with a control loop for the doubly fed induction generator (DFIG). To begin, the resonant controller is integrated into the converter controllers of the DFIG system to determine the optimal placement that yields enhanced damping characteristics. Subsequently, an analysis is conducted to explore the impact of different parameters associated with the resonant controller on system stability, with the goal of identifying the most suitable parameter configuration. The proposed control strategy is thoroughly evaluated through time-domain simulations and small signal stability analysis, considering various compensation levels, wind speeds, and sub-synchronous control interactions (SSCI). Furthermore, a comparative analysis is performed between the proposed method and a recent SSO damping technique to validate the efficacy and robustness of the proposed approach. The results of the comparison clearly demonstrate the superiority and effectiveness of the proposed control strategy in alleviating SSO. Specifically, the proposed method achieves the shortest SSO damping time across all feasible operational scenarios, thereby reinforcing its practical value and applicability.