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MICROGRID COMMUNICATION: HARDWARE AND SOFTWARE TECHNOLOGIES
Title
MICROGRID COMMUNICATION: HARDWARE AND SOFTWARE TECHNOLOGIES
Creator
GONG, WENLONG
Date
2019
Description
The Keating Nanogrid at Illinois Institute of Technology (IIT) was designed to be an islandable ac/dc hybrid nanogrid. The on-site rooftop...
Show moreThe Keating Nanogrid at Illinois Institute of Technology (IIT) was designed to be an islandable ac/dc hybrid nanogrid. The on-site rooftop solar and battery system are supporting the interconnected dc and ac subsystems. The nanogrid system at the ac bus is eventually interconnected with the IIT Microgrid. The battery storage system at Keating Nanogrid was designed to support its critical loads for about 8 hours daily. A battery management system (BMS) was employed so that it can monitor and report storage system status to the Keating Nanogrid controller for optimal decision making.The dc load including 94 fixtures controllable LED lighting system was designed to replace the original 189 fixtures ac florescent lighting system. The LEDs’ dc-dc driver was designed and built to enable the dc input provided by the rooftop solar photovoltaic system. The dc system control and communication module was designed and built to make the LED lights controllable individually by the Keating Nanogrid controller or sensor network.To enhance safety at night, 4 islandable LED streetlights were deployed on the east side of the Keating Nanogrid where grid connection was not available for lighting. The east-side streetlight is self-sustained with its own wind turbine, solar panel and battery. The real-time monitoring system was designed and built for the streetlights.The Keating Nanogrid was designed for multiple purposes including the monitoring and control of all elements via pertinent communication pathways. It exchanges the real-time information with the IIT Microgrid and together they make optimal operation decisions to enhance efficiency and reliability of the entire IIT Microgrid system.
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A Risk-Based Approach in Selecting Design Natural Hazard Loads for Temporary Structures
Title
A Risk-Based Approach in Selecting Design Natural Hazard Loads for Temporary Structures
Creator
Saleh, Eman
Date
2020
Description
Temporary structures are systems that are used for short period applications such as in maintenance and retrofit applications or for staged...
Show moreTemporary structures are systems that are used for short period applications such as in maintenance and retrofit applications or for staged performances. Examples of its applications are tents, scaffoldings, and other facilities that have a short service life. Structures under construction and structures under serviceability conditions also fall under this category of structures; because their service time period is only limited to the duration of the construction, which is much shorter than the lifetime of the finished structure. One of the main characteristics of these types of structures is their high vulnerability to stability. Most specifications rarely cover temporary structures. Designing these structures to appropriate levels of the dead and live load does not impose an issue, in which using the same load factors as in permanent structures is considered a reasonable choice. However, an issue is raised when choosing the appropriate wind, seismic and snow load levels, where using the same exposure levels as in permanent structures may not be a desirable economic decision. Thus, for temporary structures, it makes sense to reduce the extreme event design loads proportional to the intended design life. In this manner, it is imperative to have specific rules or guidelines that would address the design aspects and reliability of these structures especially against lateral loads such as wind and earthquakes. This study aims at establishing several decision-making processes that could help contractors, designers, and erectors of temporary works to decide upon safety factors and/or return periods for environmental loads, with emphasis on the wind load. This decision-making process can be used in temporary projects (e.g., bridge erecting) to establish a design criterion based on the nature of the project. The study shows that the optimal decision-making process depends on the willingness to take advantage of wind locality characteristics (e.g., seasonality factor) in certain construction period or region, type of information available for the decision-maker (i.e., precise or imprecise), the risk associated with the constructed facility or the temporary structure itself, a potential for recourse actions, and the decision-maker’s attitude toward the trade-off between losses and gains with respect to uncertainty. The suggested decision-making process proposed is Bayesian decision process, the fuzzy decision process; (3) a two-stage stochastic programming solution; and (4) case-based decision theory. Several practical examples are presented in this thesis to show how different situations may require varying decision-making processes in order to reach the optimal decision. The design of temporary structures can be altered in response to a forecasted hurricane; thus, we propose a three-stage stochastic programming solution to decide upon their optimal wind design load. In addition, we extend the hurricane catastrophe models for application in temporary structures. This enables contractors to forecast the hurricane losses as a basis for estimating the adequate catastrophe cover such as insurance premiums and reinsurance for temporary structures. This scheme is then illustrated in an example for deciding the required temporary bracings for a steel frame under construction during the hurricane season.To prevent temporary structures from collapse, it is important to investigate the performance quality of previous projects and remove any causes for potential mishaps. This can be done by continuous monitoring of different projects and an investigation of accidents, if any, to help prevent future failures. In this study, we use an audit evidence scheme based on commonly available evidence theories used in the construction industry. In one such theory, the evidence is represented via a tree structure, in which the propagation is toward the variables that represent the project as a whole and separate work packages within a project. For simplicity, we only consider the binary case of variables i.e. whether or not a project conforms to the quality standards. The formulation of the auditing tool relates belief functions to the assertion of the quality assurance and quality control (QA/QC) measures and provides formulas for human error risk. These formulas provide plausibilities of human error in a belief-function format. An auditor may use the belief values to assess the degree of quality performance and to identify the sources of the problem in temporary work. We further illustrate the method in a practical application to evaluate the shoring/reshoring operations for estimating the construction risk in a multistory concrete structure. This evaluation may be used to decide on an appropriate time for formwork removal, shoring/reshoring schedule, casting cycles, post-tensioning sequence, and the required number of reshoring levels given the available evidence. To reduce the computational burden, we describe the shoring/reshoring system as a multi-state system (MSS) where the universal generating function (UGF) was used to estimate the reliability of the system.
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