# Special Issue on Microgrids/Nanogrids Implementation, Planning, and Operation
## 2 Special Issue Contributions  
This section briefly presents the special issue published papers' main contributions. [PERSON] et al. in [2] addressed the issues of operation cost and energy waste caused by wind and light abandonment. Indeed, energy management systems efficiency is a major concern for wind-PV and storage electric vehicle systems, where optimized operation and flexible scheduling are coordinated with the power grid. In this context, a time-sharing scheduling strategy has been proposed based on the storage system's state of charge and flexible equipment. A quantum mayfly algorithm has also been designed to implement the strategy. The scheduling results have shown that the proposed time-sharing scheduling strategy can reduce the system cost by 60%, and the method decreases energy waste compared with ordinary scheduling methods when using the quantum mayfly algorithm. [PERSON] et al. in [3], consider power quality problems such as voltage sag, swell, and harmonics can significantly affect the systems performance. To address these issues, thedynamic voltage restorer became very popular while to become effective fast responsive-operating, fast and accurate detection of sag and swell is essential. However, calculating the voltage magnitude, for comparison purposes, can be tricky in the presence of nonlinearities such as harmonics. In this context, a single-phase quasi-type-1 phase-locked loop, including a pre-loop filter composed of a frequency-fixed delayed signal cancellation method, and a two-stage all-pass filter has been proposed. This pre-loop filter is easy to implement and can provide rejection of any measurement offset thanks to the frequency-fixed nature. The carried out experiments have shown that the proposed method is fast in detecting and compensating any grid voltage anomalies to maintain constant load voltage despite voltage sag, swell, and harmonic distortions. [PERSON] et al. in [4], analyzed the benefits of sharing two stand-alone facilities from a reliability standpoint. In this context, a random sequential Monte Carlo simulation was applied to a cooperative microgrid to evaluate the impact of a simple cooperative strategy on cluster reliability. It was found that the reliability of the system increases when cooperation is allowed. Furthermore, at the design stage, this allows for more cost-effective solutions than individual sizing with a similar level of reliability. The proposed study should be beneficial in optimizing energy consumption, generation, and storage in neighboring communities with distributed energy resources. [PERSON] et al. in [5], addressed the problem of microgrids distributed generations optimal sizing and sitting with the objectives to minimize the resources generation cost and mitigate power losses. In this context, it has been proposed to use the lightning attachment procedure optimization It has been shown that this procedure outperforms the artificial bee colony approach in terms of convergence speed and the accuracy of solution-finding. In addition, to handle PV generation and load forecasting uncertainties, the lognormal distribution model and the Gaussian process quantile regression (GPQR) approaches have been adopted. [PERSON] et al. in [6], addressed the issues of microgrids stability and performance optimization for different types of loads, including the problem of harmonic cancellation and output voltage disturbance mitigation of distributed generation resource systems caused by nonlinear loads. In this context, robust proportional-resonant controllers with a harmonics compensator based on the internal model principle have been proposed. These controllers ensure robust tracking of sinusoidal reference signals in distributed energy resource systems subject to load variation with respect to sinusoidal disturbances. [PERSON] et al. in [7], proposed to address microgrids challenge of optimal design of the hybrid system while considering both economic cost and location installation feasibility.