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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Some Aspects of Distribution System Planning in the Context of Investment in Distributed Generation

Wong, Steven M. January 2009 (has links)
A paradigm shift in distribution system design and planning is being led by the deregulation of the power industry and the increasing adoption of distributed generation (DG). Technology advances have made DG investments feasible by both local distribution companies (LDCs) and small power producers (SPPs). LDCs are interested in finding optimal long term plans that best serve their customers at the lowest cost. SPPs, as private entities, are concerned about maximizing their rates of return. Also keenly interested in distribution design and planning is the government, which, through an electricity regulator, strives to meet DG penetration and emissions reduction goals through policy implementations. This thesis first examines the distribution system planning problem from the LDC's perspective. An innovative hierarchical dynamic optimization model is proposed for the planning of distribution systems and the energy scheduling of units that is also capable of reconciling uncoordinated SPP investments in DG. The first stage of the two-stage framework consists of a siting-cum-period planning model that sets element sizing and commissioning dates. The second stage consists of a capacity-cum-production planning model that finalizes element capacities and energy import/export and production schedules. The proposed framework is demonstrated on a 32-bus radial distribution system. Four case studies encompassing different policy sets are also conducted, demonstrating that this model's usefulness also extends to predicting the impact of different energy policies on distribution system operation and economics. The analysis of different policy sets is further expanded upon through the proposal of a new mathematical model that approaches the distribution design problem from the regulator's perspective. Various case studies examining policies that may be used by the regulator to meet DG penetration and emissions goals, through DG investment, are constructed. A combination of feed-in-tariffs, CO$_2$ tax, and cap-and-trade mechanisms are among the policies studied. The results, in the context of Ontario, Canada and its Standard Offer Program, are discussed, with respect to achieving objectives in DG investment, participation by SPPs, consumer costs, and uncertainty in carbon market prices. In jurisdictions such as Ontario, the LDC cannot invest in its own DG capacity but must accommodate those of SPPs. With the successful implementation of DG investment incentives by the regulator, there is a potential for significant investments in DG by SPPs, which may exceed that of the LDCs ability to absorb. This thesis proposes a novel method that can be used by the regulator or LDC to fairly assess, coordinate, and approve multiple competing investments proposals while maintaining operational feasibility of the distribution system. This method uses a feedback between the LDC and SPPs to achieve maximum investor participation while adhering to the technical operational limits of the distribution system. The proposed scheme is successfully demonstrated on a 32-bus radial distribution system, where it is shown to increase SPP-DG investments and production, improve the system's voltage profile, and reduce losses.
82

Some Aspects of Distribution System Planning in the Context of Investment in Distributed Generation

Wong, Steven M. January 2009 (has links)
A paradigm shift in distribution system design and planning is being led by the deregulation of the power industry and the increasing adoption of distributed generation (DG). Technology advances have made DG investments feasible by both local distribution companies (LDCs) and small power producers (SPPs). LDCs are interested in finding optimal long term plans that best serve their customers at the lowest cost. SPPs, as private entities, are concerned about maximizing their rates of return. Also keenly interested in distribution design and planning is the government, which, through an electricity regulator, strives to meet DG penetration and emissions reduction goals through policy implementations. This thesis first examines the distribution system planning problem from the LDC's perspective. An innovative hierarchical dynamic optimization model is proposed for the planning of distribution systems and the energy scheduling of units that is also capable of reconciling uncoordinated SPP investments in DG. The first stage of the two-stage framework consists of a siting-cum-period planning model that sets element sizing and commissioning dates. The second stage consists of a capacity-cum-production planning model that finalizes element capacities and energy import/export and production schedules. The proposed framework is demonstrated on a 32-bus radial distribution system. Four case studies encompassing different policy sets are also conducted, demonstrating that this model's usefulness also extends to predicting the impact of different energy policies on distribution system operation and economics. The analysis of different policy sets is further expanded upon through the proposal of a new mathematical model that approaches the distribution design problem from the regulator's perspective. Various case studies examining policies that may be used by the regulator to meet DG penetration and emissions goals, through DG investment, are constructed. A combination of feed-in-tariffs, CO$_2$ tax, and cap-and-trade mechanisms are among the policies studied. The results, in the context of Ontario, Canada and its Standard Offer Program, are discussed, with respect to achieving objectives in DG investment, participation by SPPs, consumer costs, and uncertainty in carbon market prices. In jurisdictions such as Ontario, the LDC cannot invest in its own DG capacity but must accommodate those of SPPs. With the successful implementation of DG investment incentives by the regulator, there is a potential for significant investments in DG by SPPs, which may exceed that of the LDCs ability to absorb. This thesis proposes a novel method that can be used by the regulator or LDC to fairly assess, coordinate, and approve multiple competing investments proposals while maintaining operational feasibility of the distribution system. This method uses a feedback between the LDC and SPPs to achieve maximum investor participation while adhering to the technical operational limits of the distribution system. The proposed scheme is successfully demonstrated on a 32-bus radial distribution system, where it is shown to increase SPP-DG investments and production, improve the system's voltage profile, and reduce losses.
83

Electric distribution system risk assessment using actual utility reliability data

Feng, Zhe 21 April 2006 (has links)
This thesis describes the research conducted on the use of historical performance data in assessing the financial risk for a power distribution utility in a performance based regulation (PBR) regime. The historical utility data used in this research are taken from the Canadian Electrical Association (CEA) annual reports. The individual utility data in these reports are confidential and only provided to the participating utilities. Thirteen utilities that participate in the CEA data reporting activity agreed to provide their individual utility data for the research described in this thesis. These utilities are anonymous and are referred to by numerical designations in accordance with the CEA protocol. This research could not have been conducted without the support of these utilities. The objectives of the research described in this thesis are to examine and analyze the variations in the annual performance indices of the thirteen participating utilities and the aggregated systems including the overall indices and the cause code contributions, and to examine the possible utilization of historic utility reliability indices to create suitable reward/penalty structures in a PBR protocol. The potential financial risk and actual financial payment analyses for these selected utilities are conducted using their historical performance data imposed on a number of possible reward/penalty structures developed in this thesis. An approach to recognize adverse utility performance in the form of Major Outage Years (MOY) is developed and the influence of the MOY performance in PBR decision making is examined.
84

Distribution Situations Concerning Transportation and Environmental Impact;   Multiple Case Studies of Medical Manufacturers in China. : Transportation and Environmental Impact reduction

Mughal, Muhammad Riaz, Zhao, Zhe January 2011 (has links)
Background: The environmental aspect of transportation has got a lot of attention over the past years. It has its origin in the growing awareness of environmental problems such as the global warming. In Europe the transportation industry is responsible for 21 per cent of the total emission. While studies of the subject show that an environmental friendly distribution and transportation is considered a success factor for many companies, there is a lack of interest from them to invest to obtain it. Purpose: The purpose of this paper is to find the current distribution situations and the factors that influence the transportation and environmental impacts while maintaining the same customer service level, as well as how these factors will influence distribution situations in some Chinese medical instrument manufacturing companies. Method: To gather data the authors will conduct a qualitative multiple case studies in the form of interviews at couple of medical equipment manufacturing companies to create the deep understanding needed to comprehend a company’s distribution system. Results, conclusion: Initially, the current situation of distribution system in Chinese medical instrument manufacturing companies has been found according to the cases companies’ analysis. Second, the four factors which would influence transportation and the environmental impact while keeping the same customer service level have been identified. They are fill rate, consolidation, standardization and postponement. Furthermore, benefiting how these factors will influence distribution situation through efficiency in transportation has been given as the suggestion and recommendation to some Chinese medical instrument manufacturing companies.
85

Alleviations of Substation Congestions by Distributed Generations ¡V An Optimal Location and Reliability Analysis

Melvin, Galicia 18 July 2011 (has links)
With increased load demands from the customers, substation congestion problems have become inevitable to the utility companies. Instead of expanding related system installations to alleviate the short-term overloads on the facilities, feasibilities of integrating distributed generator (DG) units to defer the possible congestions are of much concern. This thesis presents an optimal location and reliability analyzing scheme for distribution system integrated with DG units, and provides the systematic guidance to utility companies for related operations. The methodology focuses on the substation capacity constraints and provides the optimal DG locations that can alleviate the congestion problem with highest reliability indices. The proposed analyzing scheme can supply valuable assistance to the utility companies and small independent power producers (IPP) for determining the installations and integrations of DG units to defer possible emerging substation expansions.
86

Design of D-STATCOM for Voltage Regulation in Radial Feeders

Chan, Yu-Hung 21 October 2011 (has links)
Distributed generation (DG) has received much attention recently due to environmental consciousness and rising of the energy efficiency. However, DG interconnecting to low-voltage distribution system may cause voltage variation, and a lot of single-phase DG or single-phase load may result in voltage unbalance. This thesis presents a distributed-STATCOM (D-STATCOM) to alleviate variation of both positive-sequence and negative-sequence voltages at the fundamental frequency. The D-STATCOM operates as susceptance and conductance at the fundamental positive-and negative-sequence frequency, respectively. The susceptance and conductance commands are dynamically tuned according to voltage fluctuation at the installation location. Therefore, the positive-sequence voltage can be restored to the nominal value as well as the negative-sequence voltage can be suppressed to an allowable level. Computer simulations and experimental results verify the effectiveness of the proposed control strategy.
87

Estimating Hurricane Outage and Damage Risk in Power Distribution System

Han, Seung Ryong 15 May 2009 (has links)
Hurricanes have caused severe damage to the electric power system throughout the Gulf coast region of the U.S., and electric power is critical to post-hurricane disaster response as well as to long-term recovery for impacted areas. Managing hurricane risks and properly preparing for post-storm recovery efforts requires rigorous methods for estimating the number and location of power outages, customers without power, and damage to power distribution systems. This dissertation presents a statistical power outage prediction model, a statistical model for predicting the number of customers without power, statistical damage estimation models, and a physical damage estimation model for the gulf coast region of the U.S. The statistical models use negative binomial generalized additive regression models as well as negative binomial generalized linear regression models for estimating the number of power outages, customers without power, damaged poles and damaged transformers in each area of a utility company’s service area. The statistical models developed based on transformed data replace hurricane indicator variables, dummy variables, with physically measurable variables, enabling future predictions to be based on only well-understood characteristics of hurricanes. The physical damage estimation model provides reliable predictions of the number of damaged poles for future hurricanes by integrating fragility curves based on structural reliability analysis with observed data through a Bayesian approach. The models were developed using data about power outages during nine hurricanes in three states served by a large, investor-owned utility company in the Gulf Coast region.
88

Influences of distribution system and advanced treatment technology on drinking water quality

Lee, Wei-li 14 June 2006 (has links)
The purposes of this study include: (1) investigating the reasons why drinking water quality degrades during transportation in the distribution system and developing an easy and effective tool to evaluate the status of distribution system; (2) investigating residents¡¦ satisfaction with advanced treated drinking water. It is found that the main reason of drinking water degradation is that most people don¡¦t flush the drinking water storage facilities routinely. It is also found that although most respondents are satisfied with advanced treated drinking water, nearly 40% of local residents still buy bottle water instead of drinking tap water. Therefore, Taiwan Water Supply Corp. (TWSC) should let people know the importance of flushing water storage facilities routinely and what TWSC has done to improve drinking water quality. The LSI (Langelier Saturation Index) of most water samples is negative, which means that the drinking water is corrosive when too much hardness is removed to comply with the regulations. A simple, efficient and cost-effective method is developed to provide TWSC sufficient information to solve the problems regarding water quality degradations in distribution systems. By using contour maps of different water quality parameters, TWSC can easily identifies locations with potential problems and easily assesses the necessity and appropriate locations of building re-chlorination stations, even though the lack of information regarding pipeline material, hydraulic conditions, thickness of biofilm¡Ketc.
89

Losses In Electric Distribution System

Ozel, Kerem 01 December 2006 (has links) (PDF)
The purpose of this thesis is to examine the technical losses in Electric Distribution Systems, the sources of the losses, minimum levels of the losses, ways to decrease the losses and current applications in Turkey. The wrong and weak parts of the current applications are determined and emphasized. Ways to decrease losses in Distribution Systems are advised. The energy resources in the world are decreasing rapidly. There is a rapid growth in consumption. It is a must to use existing resources in most efficient way because there is no unlimited energy source. Losses in the electric distribution systems are one of the most important subjects because the most of the technical losses in electric systems occur in the distribution systems.
90

Water System At The Upper City Of Hasankeyf And Its Impact On Urban Settlement

Oguz, Eser Deniz 01 February 2007 (has links) (PDF)
Hasankeyf, located in Upper Mesopotamia, southeastern Turkey with its environs at the floodplains of Tigris, welcomed many cultures in different periods. It has a very unique status with its difficult topography and distinctive outlook where spatial urbanization in almost every period must have been extraordinary, as well. The aim of this thesis is to study the water distribution system, specifically its relation to natural and man-made environment, at the Upper city of Hasankeyf, in order to identify the impact of utilization of water on the urban structure, with a new perspective. The thesis tries to explain the designation of urban patterns and understand possible late settlement strategies in the light of cistern-incentive and available canal data collected at the Upper city. The identification of 185 cisterns and their various characteristics helps to make different analyses to establish links between the water system and settlement areas at macro and micro levels, which go hand in hand with mapping studies. Notwithstanding the abovementioned objectives, this study endeavors to find some common denominators with Roman water practices, which are considered to be comparable to those of Hasankeyf, thus unveil some clues for Hasankeyf water features. It now appears that water and urban settlement are two sides of a coin where water can not be treated as the sole determinant on the development of settlement patterns in which case the urban settlement also has impact on the water distribution at the Upper city.

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