Improvement of System Reliability and Public Safety Using Covered Conductors for Overhead Distribution Systems
| Autor: | Ming-Bin Li, 李名濱 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 The overhead distribution system has been constructed using mainly bare wires, and the bare wire is not insulated. The accidents occurred in overhead distribution lines are mostly caused by external contact faults which the public electric shock accident is one of reasons. These accidents will lead to reduce the reliability and the public safety of distribution systems. A modern distribution system should not only be concerned about how much economic benefit can be obtained from improving reliability, and must be able to give a guarantee of the safety level about the public lives. The reliability index is a time series to be observed and collected per year in distribution systems. In addition, another time series is to be concerned about the public safety on the occurred number of public received electric shocks per year in this dissertation. The covered conductors used in overhead lines have achieved in positive results during the recent years. For overhead distribution systems, the reliability of covered overhead lines could potentially be improved using various alternative technologies. Overhead distribution lines using the covered conductors can effectively reduce the number of the external contact faults, thus improve the reliability. Therefore, this dissertation tries to reflect on the effect of the reliability and the public safety for distribution systems using the covered conductors. The basic approaches of reliability assessment in power distribution systems are the analysis and the probabilistic simulation. This dissertation defines a set of endangered-life indices for public safety. The statistical two-sample t significance test presented in this dissertation can be used to determine the cause-and-effect relationships that exist between the covered rates and the reliability indices including public safety. In overhead distribution lines with different covered rates, the Poisson distribution, a probability statistics method, is used to analyze the probability distribution of the occurred numbers of endangered-life indices and to compare with simulations using discrete inverse transform method. Moreover, because outage events occur at unpredictable times and for different reasons, the Monte Carlo simulation approach (MCS) is a useful method that can use a computer to rapidly generate a large number of trials to simulate outage events. A practical test system is employed to analyze and simulate the reliability and safety indexes in this dissertation. The study results show that covered rates must increase greatly enough (approximately 40%) to improve the public safety. As covered rates increase, the levels of reliability and economic benefits increase. Thus, contact fault events in which a person receives an electric shock will decrease for distribution systems. Therefore, the effect of covered overhead lines cannot be described simplistically by economic quantification — the reduction in the annual number of people electrocuted is the most significant result of improving the public safety. Finally, this study focuses on how to predict the reliability and the public safety with respect to covered rates using time series modeling for the distribution system of TPC. We focus on how to forecast the reliability indices and public safety on covered rates using two regression models which are the logistic regression and dynamic regression models. The dynamic regression model is to combine the logistic regression model with time series errors in autoregressive-moving average analysis process. Results of the two fitted regression models for system reliability and public safety of TPC are presented with the square of the correlation, which are useful for planners to make decisions. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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