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Microgrid deployment in electric grids improves reliability, efficiency, and quality, as well as the overall sustainability and resiliency of the grid. Specifically, microgrids alleviate the effects of power outages. However, microgrid implementations impose additional challenges on power systems. Microgrid protection is one of the technical challenges implicit in the deployment of microgrids. These challenges occur as a result of the unique properties of microgrid networks in comparison to traditional electrical networks. Differential protection is a fast, selective, and sensitive technique. Additionally, it offers a viable solution to microgrid protection concerns. The differential zone protection scheme is a cost-effective variant of differential protection. To implement a differential zone protection scheme, the network must be split into different protection zones. The reliability of this protection scheme is dependent upon the number of protective zones developed. This thesis proposes a new differential zone protection scheme using a graph partitioning algorithm. A graph partitioning algorithm is used to partition the microgrid into multiple protective zones. The IEEE 13-node microgrid is used to demonstrate the proposed protection scheme. The protection scheme is validated with MATLAB Simulink, and its impact is simulated with DIgSILENT PowerFactory software. Additionally, a comprehensive comparison was made to a comparable differential zone protection scheme. / Master of Science / A microgrid is a group of connected distributed energy resources (DERs) with the loads to be served that acts as a local electrical network. In electric grids, microgrid implementation enhances grid reliability, efficiency, and quality, as well as the system's overall sustainability and resiliency. Microgrids mitigate the consequences of power disruptions. Microgrid solutions, on the other hand, bring extra obstacles to power systems. One of the technological issues inherent in the implementation of microgrids is microgrid protection. These difficulties arise as a result of microgrid networks' distinct characteristics as compared to standard electrical networks. Differential protection is a technique that is fast, selective, and sensitive. It also provides a feasible solution to microgrid protection problems. This protection scheme, on the other hand, is more expensive than others. The differential zone protection scheme is a cost-effective variation of differential protection that lowers protection scheme expenses while improving system reliability. The network must be divided into different protection zones in order to deploy a differential zone protection scheme. The number of protective zones generated determines the reliability of this protection method. Using a network partitioning technique, this thesis presents a new differential zone protection scheme. The microgrid is divided into various protection zones using a graph partitioning algorithm. The proposed protection scheme is demonstrated using the IEEE 13-node microgrid. MATLAB Simulink is used to validate the protection scheme, while DIgSILENT PowerFactory is used to simulate its impact. A comparison of a similar differential zone protection scheme was also done.

A substation must be properly protected against lightning and other external effects to the equipment in the station or staff, for that we use relay protection. They should also protect against internal errors which may occur as ground faults. There are different types of protection relays, but most common are overcurrent-, distance-, residual current- and differential protection. The purpose of this thesis was to deepen our knowledge of relay protection and to use the theoretical knowledge we got from the university studies in the work process. In the process we discovered which parameters were the most essential and calculated these for all relay protections on the substation. We also carry out a comparison between two brands of relay protection, ABB and Alstom. During our work we will test and simulate the over-current relays in a program called NEPLAN, the program will also calculate the fault currents. It was also supposed to test the other protection types, but we were limited to over-current protection when the software license didn´t apply to the other. In our work we will include much theoretical material with information about the components around the protections and substation and the calculations that’s included.

https://vimeo.com/142533096</p Every time I am on an elevator or an airplane there is always someone right behind me, or beside me, that is coughing or sneezing. That is implied in the film with the use of, among other sounds, a sneeze, that speaks about the uncontrollable. So there are definitely contradictions with these railings, as they are an idea of a support structure that in practice doesn’t really work. And this recurs in the video work where you’re trying to clean a piece of acrylic glass which, in itself, is an impossible task. As soon as you try to clean it you get marks on it. It’s an unprotected surface as soon as you pull off the plastic film and even if you leave it on when the pane is scratched marks build up under it. / SIX MINUTES OF FRESHNESS

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In recent decades, concerns about potential health effects resulting from exposure to contaminants that cause indoor air pollution have dramatically increased. The purpose of this study was to assess the indoor air quality of three buildings at Western Kentucky University and to examine and characterize indoor levels of basic comfort parameters, carbon dioxide, and fungi as well as occupants' perceptions of poor indoor air quality and the role of fungi on reported health symptoms. The three buildings included in the study were: Tate Page Hall (TPH), Jones Jagger Hall (JJH) and Science and Technology Hall (STH). Fifty-three questionnaires were completed by faculty and staff in the three buildings. The questionnaires, in addition to a walkthrough inspection and information from the Environmental Health and Safety Director and building coordinators formed the basis for classification of the three buildings (TPH and STH as complaint and JJH as noncomplaint). Comfort parameters, CO2, and fungi were measured indoors at selected offices for approximately five hours each day in summer of 2004. Measurements were also made outdoors for comparison of indoor samples. Airborne samples for viable fungi were collected onto malt Extract Agar using a single-stage Impactor calibrated at a flow rate of 28 liters per minute (L/min) for five minutes. Air samples for non-viable fungi were collected with Air-O-Cell Cassettes using the SKC Bio-Pump at a flow rate of 15L/min for ten minutes. Additionally, bulk samples were collected from areas with visible molds. The fungal samples were sent to two contract and accredited laboratories for analysis. The basic parameters were analyzed using descriptive statistics and analysis of variance. The results of the questionnaires showed response rates of 35 % for STH and TPH, and 30 %, for JJH. The most common indoor air quality (IAQ) complaints were allergies (27%), mold (27%), dust in the air (17%), temperature (13%), lack of airflow or stuffiness (10%), and physical symptoms (7%). The average indoor levels of basic parameters were within the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE's) recommended limits for both complaint buildings. ANOVA results showed that the levels of environmental measurements differed significantly across buildings. Airborne indoor concentrations of fungi were significantly higher than the outdoor in STH and TPH. Whereas JJH had less than 50% indoor fungi compared to outdoor. The most prevalent fungi were Aspergillus, Acremonium Cladosporium, Penicillium, and Yeast. However, certain toxin producing fungi (Penicillium, Aspergillus, and Stachybotrys species) that have been associated with human health effects such as asthma and allergies were isolated from a number of indoor samples at higher levels in the complaint buildings than the non-complaint building. The presence of higher indoor (compare to outdoor) levels and more species of toxigenic fungi would indicate inadequate ventilation and poor indoor air quality. Poor indoor air quality resulting from allergic diseases has been associated with increased rate of Absenteeism and reduced productivity. Remedial actions are recommended for improved building design, operation and maintenance with a view to improving indoor air quality, occupants comfort, and public health.

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