ALBERT

Description: The remarkable growth of distributed generation (DG) penetration inside electrical power systems turns the familiar passive ‎distribution networks (PDNs) into active distribution networks (ADNs). Based ‎on the backward/forward sweep method (BFS), a new power-flow algorithm was developed in this paper. The algorithm is flexible to handle the bidirectional flow of power that characterizes the ‎modern ADNs. Models of the commonly used distribution network components were integrated with the developed algorithm to ‎form a comprehensive tool. This tool is valid for modeling either balanced or unbalanced ADNs with an unlimited number of nodes or laterals. The ‎integrated models involve modeling of distribution lines, losses inside distribution transformers, automatic voltage regulators ‎‎(AVRs), DG units, shunt capacitor banks (SCBs) and different load models. To verify its validity, the presented algorithm was first applied to the unbalanced IEEE 37-node standard feeder in both passive and active states. Moreover, the algorithm was then ‎applied to a balanced 22 kV real distribution network as a case study. The selected network is located in a remote area in the western desert of Upper Egypt, far away from the Egyptian unified national grid. Accordingly, the paper examines the current and future situation of the Egyptian electricity market. Comparison studies between the ‎performance of the proposed ADNs and the classical PDNs are discussed. Simulation results are presented to demonstrate the ‎effectiveness of the proposed ADNs in preserving the network assets, improving the system performance and minimizing the ‎power losses‎.

Description: The integration of wind energy systems (WECS) into the power grid through power electronic converters should ensure the high performance of the control system. In spite of several advantages of conventional Finite control set-model predictive controller (FCS-MPC), variable switching frequency and high computational burden are considered its main drawbacks. In this paper, a fast FCS-MPC of a machine side converter (MSC) of direct-driven permanent magnet synchronous generator (PMSG) based wind turbines for wind energy conversion system is proposed. The wind energy conversion system has been realized using a direct driven PMSG and a full-scale back-to-back power converter. The proposed controller is designed to reduce the required calculations in each horizon. In addition, the performance of conventional FCS-MPC is compared with the proposed method, and an improvement in total harmonic distortion spectra and simulation time required even when imposing a lower sampling frequency was found. To overcome the variable switching frequency problem, a modulation algorithm is introduced in the minimization process of modulated FCS-MPC. To keep the proposed system attached to the utility during a fault, a coordinated pitch angle control and low voltage-ride through (LVRT) algorithm is designed and inserted in the vector control of the grid side converter (GSC) to supply reactive power to the grid during fault for ensuring safe operation of the inverter and meeting the grid code requirements. The effectiveness of the proposed controller is illustrated using simulation results under different operating conditions.