Navid Rezaei

A novel hierarchical energy management of a renewable microgrid considering static and dynamic frequency

The present paper addresses a novel energy management system to efficiently procure the frequency security requirements of an islanded microgrid. The static and dynamic behaviors of the microgrid frequency are modeled based on the droop control and virtual inertia concepts. Two novel frequency dependent indices are formulated and controlled via a centralized hierarchical energy management system. The main objective of the paper is to optimize the microgrid frequency security and also the rate of change of frequency indices by providing a sustainable strategy for managing the energy and reserve resources. It is aimed to schedule the daily primary and secondary frequency control reserves such that security is ensured subject to the techno-economic restrictions. The derived formulation is solved using a mixed integer linear programming approach regarding the comprehensive operational constraints of the microgrids which ensures the system sustainability. Meanwhile, an efficient scenario-based stochastic progr...

A novel frequency aware energy management system for a droop controlled microgrid

The present paper proposes a novel energy management system in islanded microgrids which considers static frequency. Microgrid frequency continuously deviates from the nominal value, subject to the unpredictable renewable and/or load variations. The small capacity and low inertia stack of the utilized inverter-based distributed energy resources intensify the importance of incorporating the frequency into the microgrid energy management system. Motivated by this need and owing to the direct coupling between the frequency and reserve scheduling, energy and reserve resources of an islanded microgrid are aimed to be scheduled such a way the frequency be managed securely. In this regard, first, the frequency dependent behavior of droop controlled distributed generations should be modeled in detail. Next, microgrid central controller can schedule the reserve resources in order to satisfy both economical and security issues by modification the reference power settings. Simulation results in a typical microgrid and over a daily period verify the effectiveness of the proposed frequency aware energy management system.

A Novel Current Injection Model of GCSC for Control and Damping of Power System Oscillations

The paper proposes the theory and the modeling technique of the new invention of the flexible AC transmission system (FACTS) device, i.e., Gate controlled series capacitor (GCSC) for power flow control of power transmission lines and damping of low-frequency oscillations. In this study, a current injection model of the GCSC is used for studying the effect of the GCSC on the low-frequency oscillations, which is incorporated in the transmission system model. To be sure of optimal adjustment of the applied damping controller, the particle swarm optimization algorithm is employed as an efficient heuristic optimizer to And out the near global optimum set of the damping controller parameters. The proposed model is applied to a damping controller design of a multi-machine power system. Detailed simulations are carried out with MATLAB/SIMULINK environment and the effect of the GCSC-based damping controller and the current injection model over the system stability is studied.

Diagnosis of impedance fault in distribution system with distributed generations using radial basis function neural network

In recent years, complexity of fault diagnosis in the advanced distribution networks, mainly due to the increased use of distributed generations and fault with impedance result in proposing of adaptive fault location technique using neural network. Radial basis function neural networks are used for fault diagnosis and fault location. The proposed approach reduces the complexity of the fault location in case of impedance fault. The predicted results prove the effectiveness of the proposed online automatic procedure for fast and accurate fault diagnosis of the system for a wide range of system conditions.