0000000000451870
AUTHOR
Salar Moradi
Energy Management System in Grid-Connected Small Scale AC/DC Microgrids Including Renewable Sources and Flexible Loads
The growth of small scale microgrids with diverse distributed generations has drawn attention to their effective energy management. In this paper, for various energy scenarios, an energy management system is adopted to minimize the energy purchased by a hybrid AC/DC microgrid from the upstream grid due to high peak-hour energy prices and maximise generation from renewable sources, while adjusting the most optimal charge/discharge control strategies for flexible loads such as electric vehicles and storage systems, and the supply of non-controllable loads. In addition, peak shaving is simultaneously implemented in this proposed model without considering minimum power deviation as an objective…
Dynamic Control of Static Converters for the Transition from Grid-on to Grid-off Operation of AC/DC Microgrids
In this paper, specific control logics defined for generators, controllable loads and electric energy storage systems are illustrated in order to improve the reliability of AC/DC hybrid microgrids in their grid-off operation following failure events such as short-circuits, line breaks, sudden disconnections of generating units or loads, etc. After defining specific control schemes, these were modelled in a digital environment and finally tested with dynamic simulations. Finally, the paper highlights the role of virtual synchronous machine control for the self-healing capacity of islanded hybrid microgrids.
A stochastic approach for self-healing capability evaluation in active islanded AC/DC hybrid microgrids
This paper aims to implement a resilience assessment in AC/DC hybrid microgrids using a stochastic simulation approach. Self-healing measures including load shedding, control of distributed generation and flexible devices, like Energy Storage Systems (ESS) and Electrical Vehicles (EVs), are simulated to enable AC/DC hybrid microgrids to supply critical loads in islanded mode, assuming a disconnection of these microgrids from the main AC grid due to a fault. To perform this analysis, a two-stage process is proposed: first, a Monte-Carlo simulation-based stochastic approach is adopted to generate samples to simulate intermittent loads, power generation from Renewable Energy Sources (RESs), an…
A Simulation Analysis for Assessing the Reliability of AC/DC Hybrid Microgrids - Part II: Port Area and Residential Area
This paper reports the second part of a simulation study with the aim of evaluating the ability of two portions of a hybrid AC/DC MV/LV network in maintaining their operation in off-grid mode during the loss of the main AC grid due to a failure. In particular, this paper follows a dual purpose: first, it analysis two microgrids in a residential area and a port zone capability of operating in islanded mode, applying a probabilistic approach, while there is different energy use cases, and second is to evaluate some reliability indicators.
A General Methodology for Short-circuit Calculations in Hybrid AC/DC Microgrids
In this paper, the issues related to short-circuit calculations in hybrid AC/DC microgrids are discussed. The reference standard for short-current calculations in DC systems is the IEC 61660, which provides a mathematical formulation of the problem. The standard only includes radial DC grids and does not consider a more complex system, such as meshed DC systems or a hybrid AC/DC microgrid. This paper proposes a generalized approach that can be used independently of the characteristics of the hybrid system. The proposed approach is applied to four test microgrids with different distributed sources and number of nodes and the results are compared with those obtained simulating the same grids …
Predictions in Resilient Hybrid AC/DC Grids Leveraged by an Interoperable and Secure ICT Platform
Power systems are undergoing a significant change and the main elements to address the new challenges is the new key-role played by the distribution grid and its transformation into a smart grid. While the distribution grid has traditionally operated with alternating current (AC), nowadays most devices operate with DC internally, and most distributed renewable resources generate power in DC. Furthermore, storage components, such as batteries and supercapacitors, have a DC character. DC seems to be the one of the most promising candidates to avoid stranded investments and to guarantee incredible saving for the community in Europe, making the transition to a fully decarbonised energy system a…