Optimal partitioning of unbalanced active distribution systems for supply‐sufficient micro‐ grids considering uncertainty

AbstractThis paper presents the impact of optimal location and sizing of renewable and non-renewable-based distributed generators in the AC/DC micro-grid system using the latest optimizer called butterfly optimization algorithm with an aim to minimize power loss. Generally, hybrid AC/DC micro-grids systems are modeled by separating AC and DC feeders with the help of high-power converters (HPC).AC grids sustained by substation and DC grids are maintained by their individual DG units. While planning of DGs in the hybrid AC/DC systems, the power loss incurred by HPCs is not considered avoiding complexity by many authors. In this paper, the sizing of DGs is determined by the operational area required by the type of DG technology as one variable and all possible candidate buses in the respective zones of AC/DC micro-grid system are another variable with due consideration of HPC losses in AC/DC micro-grid system. A hybrid AC/DC MG system is developed by classifying the existing benchmark 33-bus and 69-bus radial distribution systems into various AC/DC zones. To evaluate the proposed approach, it is implemented on aforementioned micro-grid systems and the obtained results are verified with other existing approaches in the literature. The results proved that the proposed approach is better than the other approaches in technical aspects.

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Comparing Utility Connected to Stand Alone Micro-Grids: From the Viewpoint of a Utility Engineer

ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C ◽

10.1115/es2011-54833 ◽

2011 ◽

Author(s):

Mike Hoffman ◽

Brian Russo

Keyword(s):

Real World ◽

Distribution Systems ◽

Modeling Tools ◽

Electrical Distribution Systems ◽

Modeling Software ◽

Micro Grid ◽

Smooth Transitions ◽

Micro Grids ◽

Financial Issues ◽

Broad Overview

This paper presents project examples of grid and grid-isolated micro-grids. It discusses micro-grid drivers; economic, environmental, and financial issues; and tools to plan and design micro-grids. Tools covered include modeling software resource options, generation types, fuel options, and services to provide smooth transitions (including required equipment and software controls), ranging from those of minimal expense to maximum functionality. The need for, and construction of, real-time operational interfaces is also addressed, with a focus on real world complications and guidance regarding implementation of planning design and of a micro-grid. This paper attempts to present a broad overview of micro-grids, including project examples, modeling tools, technology options, and practical and business insights to enable interested parties to quickly come up to speed on micro-grid basics. The included information should give interested parties the tools and resources to move forward on their own projects, assuming these parties have sufficient knowledge and experience with electrical distribution systems.

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Reduction of harmonic distortion in micro grids and distribution systems with photovoltaic generators

2017 International Conference on Computation of Power, Energy Information and Commuincation (ICCPEIC) ◽

10.1109/iccpeic.2017.8290466 ◽

2017 ◽

Cited By ~ 1

Author(s):

K. Prasanna Kumar ◽

R. Vanitha ◽

S. Sai Hemesh

Keyword(s):

Distribution Systems ◽

Harmonic Distortion ◽

Photovoltaic Generators ◽

Micro Grids

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Feasibility Analysis of a DC Distribution System for a 6 kW Photovoltaic Installation in Ireland

Energies ◽

10.3390/en14196265 ◽

2021 ◽

Vol 14 (19) ◽

pp. 6265

Author(s):

Meshari Alshammari ◽

Maeve Duffy

Keyword(s):

Distribution System ◽

Distribution Systems ◽

High Efficiency ◽

Renewable Energy Sources ◽

Annual Data ◽

The West ◽

Dc Distribution ◽

National School ◽

Recent Developments ◽

Micro Grids

Recent developments in micro-grids have led to increased interest in DC distribution due to its high efficiency in distributing energy from renewable energy sources to DC loads. This paper seeks to analyse the performance of AC and DC systems in a relatively large-sized 6 kW PV installation to determine the level of improvement in efficiency provided by DC distribution and to identify methods for further improvement. Baseline annual data for the AC system were collected from a live installation on a national school in Inis Oirr, an island off the west coast of Ireland. The results indicate that usage of a DC distribution system has the potential to reduce system losses by up to 50% as well as the ability for an annual saving in grid energy of 5% compared to the existing AC system. Moreover, the analysis reveals that DC outperforms AC distribution more in spring and autumn, when power consumption is comparable to the system production, but there is less impact in summer, when PV production is significantly higher than demand. These findings provide insights into the benefits of future DC distribution systems in individual buildings and in larger-scale micro-grids.

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Robust Linear Control of Boost and Buck-Boost DC-DC Converters in Micro-Grids with Constant Power Loads

Energies ◽

10.3390/en13184829 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4829 ◽

Cited By ~ 1

Author(s):

Christos Yfoulis ◽

Simira Papadopoulou ◽

Spyridon Voutetakis

Keyword(s):

Power Distribution ◽

Distribution Systems ◽

Dominant Role ◽

Renewable Energy Sources ◽

Power Electronic ◽

Constant Power ◽

Constant Power Loads ◽

Micro Grids ◽

Mixed Load ◽

Load Conditions

Power distribution systems nowadays are highly penetrated by renewable energy sources, and this explains the dominant role of power electronic converters in their operation. However, the presence of multiple power electronic conversion units gives rise to the so-called phenomenon of Constant Power Loads (CPLs), which poses a serious stability challenge in the overall operation of a DC micro-grid. This article addresses the problem of enhancing the stability margin of boost and buck-boost DC-DC converters employed in DC micro-grids under uncertain mixed load conditions. This is done with a recently proposed methodology that relies on a two-degree-of-freedom (2-DOF) controller, comprised by a voltage-mode Proportional Integral Derivative (PID) (Type-III) primary controller and a reference governor (RG) secondary controller. This complementary scheme adjusts the imposed voltage reference dynamically and is designed in an optimal fashion via the Model Predictive Control (MPC) methodology based on a specialized composite (current and power) estimator. The outcome is a robust linear MPC controller in an explicit form that is shown to possess interesting robustness properties in a wide operating range and under various disturbances and mixed load conditions. The robustness and performance of the proposed controller/observer pair under steady-state, line, and mixed load variations is validated through extensive Matlab/Simulink simulations.

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