This paper proposes a new modified architecture for AC microgrid consisting of multiple grid-supporting master units (MUs) and multiple grid-feeding slave units (SUs). In this study, a coordinated four-layer hierarchal control (HC) approach is applied to the proposed structure for allowing the MUs, SUs and loads to be easily integrated as a microgrid and operated in both grid-integrated and standalone operation mode. The proposed structure of the AC microgrid enhances the system redundancy to prevent the single point of failure of MU and has more stability, efficiency, flexibility and reliability than the conventional structures. Furthermore, optimal design guidelines, based on a new hybrid Harries hawks and particle swarm optimization algorithm (H-HHOPSO) with the cooperation of different types of proposed multi-objective functions, are presented to fulfill the study objectives. The optimization constraints/objectives are employed for optimal parameters selection of HC controllers to improve the power quality, enhance dynamic and steady-state performance and guarantee a seamless transition between operation modes. To accomplish this work, the newly modified structure is modeled, constructed in MATLAB/SIMULINK and tested under the variations of generations and loads. This structure is also examined when the fault occurs at any one of the MUs and during the connecting and disconnecting of utility grid. This testing is to verify its flexibility and reliability, and confirm the effectiveness and robustness of the proposed optimal controllers. Additionally, the experimental work is carried out using the hardware-in-the-loop real-time emulation to prove the optimal controllers' feasibility. Finally, the experimental and simulation results are compared.

This paper proposes new analytical and optimal design procedures of the proportional‐resonant (PR) controller and its harmonic compensators (HCs) for three‐phase grid‐connected voltage source inverters (VSIs) powered by renewable energy resources. The modeling and analysis based on stationary reference frame are performed for VSIs collaborated with an L‐type filter. The theoretical verification and simulation validation of the proposed design guidelines are done to approve its effectiveness and robustness. Particle swarm, grey wolf and Harris hawks' optimization techniques are applied and compared for a proper selection of the parameters of the proposed PR controller and its HCs. To accomplish this study, multi‐objective error functions are employed and compared to minimize the total harmonic distortion of the grid output current. The proposed PR controller and its HCs are tested, using MATLAB/Simulink, along with the allowable changes of inverter output active and reactive powers, and also under the grid voltage distortion. Moreover, their performance is evaluated according to IEEE and IEC harmonics standards, and compared with the conventional PI controller based on reference frame. Furthermore, the experimental validation for the proposed controllers is done based on the hardware‐in‐the‐loop real‐time simulator using C2000TM‐microcontroller‐LaunchPadXL‐TMS320F28377S kit.

The proposed Remote SCADA System (RSS) is a smarter, faster and more reliable way to control high power machines and monitor their sensors, data, and failures. The proposed system focuses mainly on building our own complete SCADA software and not using open-source SCADA software. The proposed RSS can use unlimited number of added Remote Terminal Units (RTU) nodes and each of them can handling unlimited number of input/output and can be used under different operating systems like Windows and Android. Using RSS all machines can be monitored and controlled by a single click from anywhere at any time. By doing this a real-time response from RSS system can be achieved. It’s mainly based on standard communication techniques between remote nodes and single server-side application that talk to each node with its own ID and modify its instant database. So that every time accessing this web application, a real-time access to these nodes data and a virtual control room controls each General Purpose Input/Output (GPIO) in the selected node can be gotten. When a new event is happened in server-side program, it will be broadcasted to all related. On RSS there are two main points to deal with, the request latency and security of the system. This paper studied how the system latency and security are improved to obtain the needed values. The proposed RSS is a very secure program which have 4 security levels; authentication, authorization, RSA and CBC encryption system. Also, the encryption algorithms used in RSS are RSA and CBC block cipher encryption system. It is mixed way to prevent any attacker from breaking the cipher. First of all, RSA generates the public and private keys, and then CBC generates its Initialization vector and a random encryption key. Then a special function sends all of these keys encrypted with a pre-stored token in the data base and node memory which varied from node to another. Finally, node generates its private key from loaded public key. With this combination the speed of symmetric encryption system and the security of asymmetric encryption system can be achieved. On the other hand, the level of security firewalls needed to be Brocken by the attacker to brock the cipher is increased. The proposed system achieved low cost comparing with reported work; it is lower than Arduino + WIFI method by five times and 13 times lower than Raspberry-PI method. The proposed system is applied in educational systems, where it is used for teaching unlimited number of students Online.

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