scholarly journals Micro-Grid Design and Protection System under Several Fault Conditions

2019 ◽  
Vol 8 (6) ◽  
pp. 875-880
Keyword(s):  
Fault Analysis ◽  
Environmental Benefits ◽  
Protection System ◽  
Small Scale ◽  
Photovoltaic Module ◽  
Distributed Generator ◽  
Medium Voltage ◽  
Protection Scheme ◽  
Micro Grid ◽  
Design Protection

As distributed generators and renewable energies are now becoming the fastest growing technologies in the energy industries, the technical issues and environmental aspects are to studied and examined. The large number of small scale Micro grid components with their characteristics is a vital challenge for Micro grid modelling, operation, simulation and operation. Micro-grid gives clear, economic and environmental benefits for end users, utilities, and societies. However, their implementation faces lot of challenges, such as a protection of micro-grid. Micro-grid works in two modes, grid-connected and islanded mode that operates connected with medium voltage grid or islanded from the grid with controlled coordinate manner. The major goal of this thesis is to design protection for. First, the work is done to present the detailed description of the micro grid models and lines. Then the paper will discuss the distributed generator models that have been implemented in MATLAB/Simulink including photovoltaic module, fuel cell stack system with short term storage (Li-ion battery system). Then the fault analysis is done for the whole Micro-grid, whether the micro grid is working in fault condition or not. Then Micro grid protection is done for the grid connected modes and islanding modes of Micro grid. To design the protection system for the micro grid over current relay protection scheme is used.

Microgrid Viability for Small-Scale Cooling, Heating, and Power

2005 ◽  
Author(s):  
Lubomir A. Ribarov ◽  
David S. Liscinsky
Keyword(s):  
Net Present Value ◽  
Dimensional Space ◽  
Geographical Location ◽  
Geographic Location ◽  
Public Utility ◽  
Environmental Benefits ◽  
Cooling Power ◽  
Small Scale ◽  
Micro Grid ◽  
Chp System

Cooling, Heating, and Power (CHP) energy systems provide higher fuel efficiency than conventional systems, resulting in reduced emissions and other environmental benefits. Until recently the focus of CHP system development has been primarily on medium-scale commercial applications in a limited number of market segments where clear value propositions lead to short term payback. Small-scale integrated CHP systems that show promise of achieving economic viability through significant improvements in fuel utilization have received increased attention lately. In this paper the economic potential is quantified for small-scale (micro-grid) integrated CHP systems suitable for groups of buildings with aggregate electric loads in the 15 kW–120 kW range. Technologies are evaluated for community building groups (CBGs) consisting of aggregation of pure residential entities and combined residential and light commercial entities. Emphasis is on determination of the minimum load size (i.e. the smallest electric and thermal load for a given CBG that is supplied with electric, heating, cooling power from a CHP) for which a micro-grid CHP system is both technically and economically viable. In this paper, the operation of the CHP system is parallel with the public utility grid at all times, i.e. the grid is interconnected. Evaluations of CHP technology options using simulation studies in a “three-dimensional” space (CHP technology option, CBG load aggregation, and geographical location in the USA) were evaluated based on comparisons of net present value (NPV). The simulations indicated that as electric load increases, the viability of the CHP system (independent of the system’s size) becomes more favorable. Exceeding a system runtime (utilization) of 70% was shown to pass the break-even line in the NPV analysis. Finally, geographic location was found to have a relatively weak effect on the reported trends. These results suggest that micro grid CHP systems have the potential to be economically viable with relative independence of geographic location if adequately sized to match the load requirements.

scholarly journals Fault Analysis and Design of a Protection System for a Mesh Power System with a Co-Axial HTS Power Cable

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 220 ◽  
Author(s):  
Thai-Thanh Nguyen ◽  
Woon-Gyu Lee ◽  
Hak-Man Kim ◽  
Hyung Yang
Keyword(s):  
Power System ◽  
Fault Analysis ◽  
Protection System ◽  
Power Cable ◽  
Analysis And Design ◽  
Protection Scheme ◽  
System Protection ◽  
Protection Systems ◽  
Overcurrent Relays ◽  
System Characteristics

The uses of high-temperature superconducting (HTS) cables pose a challenge of power system protection since the impedance of the HTS cable is varied during fault conditions. The protection systems should be designed properly to ensure the reliability and stability of the whole system. This paper presents a fault analysis of the co-axial HTS cable in the mesh system and proposes a coordinated protection system. In the proposed protection system, the main protection is the differential current relay whereas the backup protections are the overcurrent and directional overcurrent relays. The normal and abnormal relay operations are considered to analyze the transient fault current in the HTS cable and evaluate the performance of the proposed coordinated protection system. Characteristics of cable impedances and temperatures under various fault conditions are presented. The proposed protection scheme is validated by the simulation in the PSCAD/EMTDC program. Simulation results show that the coordinated protection scheme could successfully protect the HTS cables in both normal and abnormal relay operations.

THE LACK OF SEA TO SUPPORT AGRI-ENVIRONMENTAL OBJECTIVES IN IRELAND'S RURAL ENVIRONMENT PROTECTION SCHEME

2011 ◽  
Vol 13 (01) ◽  
pp. 101-127 ◽  
Author(s):  
JACKIE WHELAN ◽  
JOHN FRY
Keyword(s):  
Environmental Protection ◽  
Environmental Benefits ◽  
Small Scale ◽  
Large Area ◽  
Protection Scheme ◽  
Ex Post ◽  
Environmental Objectives ◽  
Policy Objectives ◽  
High Level ◽  
Local Farm

Proposals specifically aimed at environmental benefits or enhancements are often exempt from environmental assessment, despite evidence that they can be counter-productive. This is true of agri-environmental schemes where local farm-scale actions are expected to generate large-area cumulative effects on water quality, biodiversity or landscape. Evidence suggests benefits of schemes have often been assumed rather than planned for, necessitating ex-post assessment to justify continuance. This paper argues the need for the Irish Rural Environmental Protection Scheme (REPS) to be assessed using SEA. REPS promoted a range of small-scale improvements in a bottom-up approach intended to reflect several high-level policy objectives primarily concerning environmental protection. The paper is based on analysis of "landscape protection" under the REPS from inception in 1994 until its phasing out period in 2015 when all participants will have completed their plans. The paper investigates how linking SEA to REPS had potential for harmonising with other policy objectives and therefore avoiding administrative duplication. Comparison with the Water Framework Directive suggests opportunities to connect different environmental procedures.

scholarly journals Simulating Agroforestry Adoption in Rural Indonesia: The Potential of Trees on Farms for Livelihoods and Environment

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 385
Author(s):  
Beatrice Nöldeke ◽  
Etti Winter ◽  
Yves Laumonier ◽  
Trifosa Simamora
Keyword(s):  
Climate Change ◽  
Climate Change Scenario ◽  
Agroforestry System ◽  
Environmental Benefits ◽  
Small Scale ◽  
Change Scenario ◽  
Trees On Farms ◽  
Agroforestry Adoption ◽  
Mitigate Climate Change ◽  
Small Scale Farmers

In recent years, agroforestry has gained increasing attention as an option to simultaneously alleviate poverty, provide ecological benefits, and mitigate climate change. The present study simulates small-scale farmers’ agroforestry adoption decisions to investigate the consequences for livelihoods and the environment over time. To explore the interdependencies between agroforestry adoption, livelihoods, and the environment, an agent-based model adjusted to a case study area in rural Indonesia was implemented. Thereby, the model compares different scenarios, including a climate change scenario. The agroforestry system under investigation consists of an illipe (Shorea stenoptera) rubber (Hevea brasiliensis) mix, which are both locally valued tree species. The simulations reveal that farmers who adopt agroforestry diversify their livelihood portfolio while increasing income. Additionally, the model predicts environmental benefits: enhanced biodiversity and higher carbon sequestration in the landscape. The benefits of agroforestry for livelihoods and nature gain particular importance in the climate change scenario. The results therefore provide policy-makers and practitioners with insights into the dynamic economic and environmental advantages of promoting agroforestry.

Line–Line Fault Analysis and Protection Challenges in Solar Photovoltaic Arrays

2013 ◽  
Vol 60 (9) ◽  
pp. 3784-3795 ◽  
Author(s):  
Ye Zhao ◽  
Jean-Francois De Palma ◽  
Jerry Mosesian ◽  
Robert Lyons ◽  
Brad Lehman
Keyword(s):  
Fault Location ◽  
Short Circuit ◽  
Fault Analysis ◽  
Small Scale ◽  
Solar Photovoltaic ◽  
Pv System ◽  
Safety Hazards ◽  
Point Tracking ◽  
Pv Inverter ◽  
Power Point

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to protect PV modules from damage and to eliminate risks of safety hazards. This paper focuses on line-line faults in PV arrays that may be caused by short-circuit faults or double ground faults. The effect on fault current from a maximum-power-point tracking of a PV inverter is discussed and shown to, at times, prevent overcurrent protection devices (OCPDs) to operate properly. Furthermore, fault behavior of PV arrays is highly related to the fault location, fault impedance, irradiance level, and use of blocking diodes. Particularly, this paper examines the challenges to OCPD in a PV array brought by unique faults: One is a fault that occurs under low-irradiance conditions, and the other is a fault that occurs at night and evolves during “night-to-day” transition. In both circumstances, the faults might remain hidden in the PV system, no matter how irradiance changes afterward. These unique faults may subsequently lead to unexpected safety hazards, reduced system efficiency, and reduced reliability. A small-scale experimental PV system has been developed to further validate the conclusions.

scholarly journals Dynamic Economic Dispatch On Micro Grid Electrical Systems Using Quadratic Programming

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Heri Suryoatmojo
Keyword(s):  
Power Generation ◽  
Quadratic Programming ◽  
Electric Power ◽  
Renewable Energy Sources ◽  
Economic Dispatch ◽  
Small Scale ◽  
Distributed Power Generation ◽  
Optimal Capacity ◽  
Micro Grid ◽  
Dynamic Economic Dispatch

Currently the needs of electric power increased rapidly along with the development of technology. The increase in power requirements is contrary to the availability of sources of energy depletion of oil and coal. This problem affects the national electrical resistance. To meet the needs of large electric power with wide area coverage is required small scale distributed power generation. This distributed generation (DG) of renewable energy sources sought to minimize the use of energy resources such as oil and coal and connected to the micro grid and use the battery as a power balance. Because of there are many DGs and the use of batteries, therefore it is important to determine the optimal power generation of each plant as well as the use of battery based on the optimal capacity so that requirement of electric power can be met with minimal cost each time. This optimization is known as Dynamic Economic Dispatch. In this study, the methods of Quadratic Programming is required to solve the optimization problem.

scholarly journals Microgrid system including PV generation and hybrid backup system

2021 ◽  
Author(s):  
Hooman Samani
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Energy Flow ◽  
Storage Systems ◽  
Photovoltaic Module ◽  
Energy Storage Systems ◽  
Hybrid Energy ◽  
Hybrid Energy Storage ◽  
Backup System ◽  
Micro Grid

This Master’s thesis project introduces a micro-grid system that includes a hybrid power storage backup system and photovoltaic module power generation system, which is connected to the grid and supports the hybrid backup system. The first section presents a solution or algorithm to an existing problem in an energy flow management strategy for the hybrid energy storage system. In the second section, power is provided from the photovoltaic arrays by the convenience of the Maximum Power Point Tracking (MPPT) for each photovoltaic module. The generated power will charge the storage backup system. The micro-grid is capable of selling the surplus power to the utility grid. A master controller optimizes integration, dispatching and control over the whole micro-grid operation. There have been many different control strategies and topologies presented over the years to manage the energy flow for hybrid energy storage systems; however, there are some aspects that differentiate some from others, such as real-time prediction, cumbersome architecture, full spectrum control over recourses, and cost-effectiveness. The first section of this thesis proposes a control strategy on hybrid energy storage systems based on fundamental electrical principles. The low volume and simple algorithm make the controller easy to perform on the embedded systems and quickly responds within a tiny space. The control strategy is equipped with a load prediction method, which provides a fast response at the time of load current surge. The controller architect provides the full control over all the resources. The presented controller is cost-effective by increasing the battery life and by minimizing the power loss in the hybrid storage backup system. The simulation results in two different experiments validate the efficiency and performance of the offered control strategy for hybrid backup system.

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