Distribution System In Order Research Articles

A Framework for Optimal Planning in Large Distribution Networks

Large scale distribution system planning is a relatively complex and reasonably difficult problem. This paper proposes the application of improved genetic algorithm (GA) for the optimal design of large scale distribution systems in order to provide optimal sizing and locating of the high and medium voltage (HV and MV) substations, as well as medium voltage (MV) feeders routing, using their corresponding fixed and variable costs associated with operational and optimization constraints. The novel approach presented in the paper solves hard satisfactory optimization problems with different constraints in large scale distribution networks. This paper presents a new concept based on loss characteristic matrix introduced for optimal locating of MV substations, followed by new methodology based on graph theory and GA for optimal locating of the HV substations and MV feeders routing in a real size distribution network. Minimum spanning tree algorithm is employed to generate set of feasible initial population. In the present article to reduce computational burden and avoid huge search space leading to infeasible solutions, special coding methods are generated for GA operators to solve optimal feeders routing. The proposed coding methods guarantee the validity of the solution during the progress of the genetic algorithm toward the global optimal solution. The developed GA-based software is tested in a real size large scale distribution system and the well satisfactory results are presented.

Organic characterisation tools for distribution system management

In this investigation, high-performance size exclusion chromatography (HPSEC) was used to characterise organic matter in treated drinking water at key sampling locations along two selected distribution systems (chlorinated and chloraminated). Other water quality parameters such as colour, UV254, dissolved organic carbon (DOC) and assimilable organic carbon (AOC) as measured by bacterial regrowth potential (BRP), were also determined. One of the aims of this work was to develop new tools to monitor organic character change along the distribution system in order to identify impacting factors and develop management strategies based on water quality change. This study used samples from two contrasting distribution systems with different disinfection regimes and organic characteristics together with samples generated from laboratory simulations. System 1 is a chlorinated distribution system and generally requires elevated chlorine dosage to meet the demand due to the high DOC level. System 2 is a chloraminated system with stable water quality, low DOC and low chloramine dose (mild oxidation). Molecular size distribution determination using HPSEC is a very informative technique in assessing treatment processes and in this study the appearance of a molecular peak at 1,700 Da that can be used as an indicator of biological activity in distribution systems was confirmed. The use of BRP values, for upstream and downstream samples in the distribution system, was found to be a good approach to assess biological impacts on water stability. The observed biological impact from the biofilms between the studied systems were particularly useful in confirming the organic characterisation results.

A Theoretical Solid Oxide Fuel Cell Model for System Controls and Stability Design

As the aviation industry moves toward higher efficiency electrical power generation, all electric aircraft, or zero emissions and more quiet aircraft, fuel cells are sought as the technology that can deliver on these high expectations. The hybrid solid oxide fuel cell system combines the fuel cell with a microturbine to obtain up to 70% cycle efficiency, and then distributes the electrical power to the loads via a power distribution system. The challenge is to understand the dynamics of this complex multidiscipline system and the design distributed controls that take the system through its operating conditions in a stable and safe manner while maintaining the system performance. This particular system is a power generation and a distribution system, and the fuel cell and microturbine model fidelity should be compatible with the dynamics of the power distribution system in order to allow proper stability and distributed controls design. The novelty in this paper is that, first, the case is made why a high fidelity fuel cell model is needed for systems control and stability designs. Second, a novel modeling approach is proposed for the fuel cell that will allow the fuel cell and the power system to be integrated and designed for stability, distributed controls, and other interface specifications. This investigation shows that for the fuel cell, the voltage characteristic should be modeled, but in addition, conservation equation dynamics, ion diffusion, charge transfer kinetics, and the electron flow inherent impedance should also be included.

H∞ Static Control Law for a Three-phase Shunt Active Power Filter

The aim of this work is to design a static feedback gain used to force a three-phase shunt active power filter to act as a current source capable of delivering the appropriate harmonics demanded by non-linear loads. This filter is connected in parallel to a three-phase power distribution system in order to keep the current supplied by the latter almost sinusoidal. The control design is performed using the H ∞ suboptimal control theory based on linear matrix inequalities (LMIs), with both partial and full state feedback. Numerical simulations will be presented in order to investigate the advantages of the full state feedback structure over the partial state feedback one, and to compare the performances of the corresponding H ∞ static control laws.

A study of delivery distribution in the central area by Tokyo Metropolitan Freight Survey

In this Paper, we showed the outline of the Tokyo Metropolitan Freight Survey. And we clarified the actual situation of delivery and measures of delivery.The survey found out that delivery causes traffic problems in CBD. The problems related to delivery distribution are divided into 3 types. There are 1) Concentration of Delivery Trucks 2) Parking at Road side 3) Goods Conveyance.It is important to improve the Delivery Distribution system in order to solve traffic problems in CBD. Therefore for so lving traffic problems, delivery measures have to be improved.

Model for Estimating Acute Health Impacts from Consumption of Contaminated Drinking Water

Disease transmission models predict the spread of disease over time through susceptible, infected, and recovered populations, and are commonly used to design public health intervention strategies. A modified disease model is linked to flow and transport models for water distribution systems in order to predict the health risks associated with use of contaminated water. The proposed framework provides information about the spatial and temporal distribution of health risks in distribution systems and is useful for understanding the vulnerability of drinking water systems to contamination events, as well as for designing public health and water utility strategies to reduce risks.

An application of interdependent lot size and consolidation point choice

The efficiency of consolidation points in a distribution system is driven both by the total volume transported and by the lot size in which the product travels. We examine a finished goods distribution system for a major automobile manufacturer that is setting policy concurrently for consolidation points and for the lot size of transport. Through simulation of the distribution system we show the impacts of consolidation on product holding time, volume volatility and customer service. Our results show a significant reduction in total system inventory from consolidation; however, some customers’ service is adversely affected. We then develop a methodology for determining the best combination of consolidation, direct shipment and lot size for all origins and destinations in the distribution system in order to minimize inventory holding time while simplifying operations and maintaining customer service. Preliminary results are shown which demonstrate the potential for substantial reductions in the total finished vehicle holding time in the system.

Meet Distribution Water Quality Regs

This article discusses an effort by the city of Toronto, Ontario, Canada to install permanent, dedicated sampling stations throughout broad cross sections of its distribution system in order to meet regulatory requirements for delivering consistently high‐quality water. The article describes dedicated sampling stations, how they work, and lists criteria for selecting sampling sites.

의료실의 비접지 배선방식 회로해석 및 적용에 관한 연구

오늘날 의학 및 간호학 분야는 입원 환자의 생명보존을 위하여 전기적인 의료장비에 점점 더 많이 의존해가고 있다. 그러므로 의료실의 전기 배선방식은 예기치 않은 누설전류로부터 환자 및 의료진의 안전을 위하여 정전 및 감전 대한 안전한 회로구성이 요구되고 있다. 특히 생명 유지를 위한 전기 기기를 사용하고 있는 의료실에는 지락시에도 전로의 차단 없이 전원은 계속적으로 공급 되어야 한다. 본 논문에서는 비접지 배선회로의 해석을 통하여 비접지 배선회로의 안전성과 적용 방법을 제시하였다.

A spatial decision support system for pipe-break susceptibility analysis of municipal water distribution systems

Municipal water distribution maintenance is very important for sustainable urban development. Water pipe-breaks result not only in disrupting service but also in significant loss of water, which otherwise could have been sold to the consumer. In countries where water is scarce, such as South Africa, water losses can be detrimental to the living standard of people. Water pipe-breaks can furthermore cause extensive damage to nearby lower-lying properties. Existing decision support systems available in the field of water distribution system maintenance mainly focus on leak detection and pipe rehabilitation/replacement strategies. These existing systems, however, do not address the actual causes of pipe-breaks. This paper reports on the development of a spatial decision support system (SDSS) for pipe-break susceptibility analysis. The engineer (or public works administrator) can apply the SDSS to model the complex pipe-break phenomena in a municipal water distribution system in order to identify pipes susceptible to breaking. This should promote more informed decision-making on preventative maintenance measures to be taken and their prioritisation. The SDSS has already been successfully applied to the water distribution system of Paarl (a medium-sized town in South Africa). Water SA Vol.30(1): 71-79

Discussion of "Active voltage correction for industrial plants"

The author comments on the paper by D. Ezer et al. (see ibid., vol.38, p.1641-6, 2002), briefly reviewing the proposals put forward. The author discusses the proposal to use active voltage conditioners (AVCs) as a solution to mitigate the effect of voltage sags in industrial plants, pointing out that this seems to be effective for the case studies mentioned but not, in his opinion, for a general case. The author also points out an apsect not considered in the paper which is the synchronization of the additive voltage injected by the series transformer with the voltage supply in the distribution system in order to mitigate phase jumps.

Epidemiology of endemic gastrointestinal and respiratory diseases: incidence, fraction attributable to tap water and costs to society

Since 1989, prospective epidemiologic studies have been undertaken to evaluate if tap water can be a significant source of illness. These studies have compared groups of families consuming tap water to families drinking tap water further processed by reverse osmosis to eliminate microorganisms that could have evaded treatment. Studies have focused on a single water treatment plant and distribution system in order to reduce confounding factors. The water produced by the treatment plant meets all North-American regulations (Québec, Canada and United States). All studies are based on long observation periods (16 to 18 month) of randomly chosen families distributed randomly in the observation groups. The rate of gastrointestinal illness average was 0.7 episodes/person-year and varied between 0.2 and 3.0 episodes/person-year according to the observation periods. We have observed that 10 to 30% of gastrointestinal and respiratory symptoms were apparently associated to the consumption tap water. The annual rate of hospitalisation for gastrointestinal or respiratory diseases was 0.7% and the medical visit rate was 19%. Furthermore, 25% of the participants lost at least one day of work due to these symptoms. The costs associated to these health effects could reach several millions of dollars each year for Canada with a population of 30 million people.

Epidemiology of endemic gastrointestinal and respiratory diseases: incidence, fraction attributable to tap water and costs to society

Since 1989, prospective epidemiologic studies have been undertaken to evaluate if tap water can be asignificant source of illness. These studies have compared groups of families consuming tap water to families drinking tap water further processed by reverse osmosis to eliminate microorganisms that could have evaded treatment. Studies have focused on a single water treatment plant and distribution system in order to reduce confounding factors. The water produced by the treatment plant meets all North-American regulations (Québec, Canada and United States). All studies are based on long observation periods (16 to 18 month) of randomly chosen families distributed randomly in the observation groups. The rate of gastrointeatinal illness average was 0.7 episodes/person-year and varied between 0.2 and 3.0 episodes/person-year according to the observation periods. We have observed that 10 to 30% of gastrointestinal and respiratory symptoms were apparently associated to the consumption tap water. The annual rate of hospitalisation for gastrointestinal or respiratory diseases was 0.7% and the medical visit rate was 19%. Furthermore, 25% of the participants lost at least one day of work due to these aymptoms. The costs associated to these health effects could reach several millions of dollars each year for Canada with a population of 30 million people.

The Pursuit of Marketing Productivity

Marketing realities in the packaged goods industry are changing rapidly as the channels of distribution become increasingly dominant in dictating both marketing strategies and process emphasis. Inevitably they require us to rethink both underlying concepts and practices. Seeking marketing cost‐efficiencies, especially in squeezing costs out of the distribution system in order to regain a measure of control, manufacturers are shifting away from the earlier acceptance of the broadly defined marketing concept to a narrower definition of a marketing productivity concept.

Evaluation of interrupted energy assessment rates in distribution systems

The authors illustrate how the concepts previously developed for generation systems and for composite generation and transmission systems can be extended to the area of distribution systems in order to obtain interrupted energy assessment rate (IEAR) indices for each customer load point and for the overall distribution system. The results of the proposed method are compared with those from a Monte Carlo simulation approach. The concepts involved in creating different customer sector IEARS by using appropriate customer cost functions are illustrated using an educational test system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

European Documentation Centres: Their role in EC information provision, with particular reference to the United Kingdom

European Documentation Centres (EDCs) were set up by the European Communities (EC) to facilitate the study of the EC and the European integration process in institutions of higher education. The use made of these large and rapidly expanding collections has been variable, but many EDC librarians have built up an expertise in EC documentation and have made considerable efforts to facilitate the use of these valuable centres of information by users. In the United Kingdom (U.K.) EDC librarians came together to form the Association of EDC Librarians in 1981. The Association has been active in promoting knowledge about EC documentation to its members and others interested in EC information. The association has also been instrumental in some of the improvements in the organisation of the EDC network and in EC documentation generally that has taken place in the 1980s. There has recently been considerable uncertainty amongst EDC librarians in the United Kingdom and other countries about their role in overall EC information provision. The European Commission has attempted to rationalise the EDC network by introducing a new selective distribution system in order to cut costs. This will seriously undermine efforts by EDC librarians to fully exploit their collections and to promote EC information services to a wider community than those in the academic institutions in which they are based. Can, or should, EDCs be seen as an integral part of EC information policy working in close cooperation with the institutions and the Press and Information Offices to promote Europe? If all, or some, EDCs are to carry out this function, there are implications in terms of finance (staffing, additional resources in equipment, and material) and attitudes (the Commission has to clarify its position towards EDCs, and librarians/documentalists have to move beyond being custodians of EC documentation to becoming experts in the information contained within the documentation). The involvement of EDCs in the Euro Info Centre (EIC) initiative provides one way forward.

The determination of the composition of aluminate ions in sodium hydroxide solution by anion exchange

A method with a low-crosslinked anion exchange resin for determining the charge number of a complex ion has been proposed. By the use of this type of resin, the charge analysis may easily be done under reasonable assumptions, because the experimental conditions where the concentration of ligand or the ionic strength is considered to be similar for the solution and the resin phase can be attained over a considerably wide region. In addition, a method for the determination of the polymerization number of a complex ion using the same resin has also been proposed. In this method an anion indifferent for the complex formation has been added to the distribution system in order to make the equilibrium analysis easy. These methods have been applied to the aluminum-hydroxo complex system. It has been presumed that the most of aluminate ions are present always in a monocharged and mononuclear form Al(OH) 4 − in ∼ 1 M sodium hydroxide solutions, although these species tend to precipitate gradually.

Short-circuit currents and recovery voltages

FIELD tests were made on a 7,200/12,470Y-volt multigrounded rural distribution system to check fault current calculations and to investigate transient recovery voltages experienced as a consequence of clearing fault currents. Tests were also made using a miniature circuit representation of a rural distribution system in order to investigate the effect of variations in circuit conditions incident to the fault. The use of the miniature system or transient analyzer made possible a determination of the order of magnitude of crest voltages and rates of rise that may be expected under most severe conditions. The work is expected to be of considerable value in the preparation of standards for the testing of such devices as expulsion lightning arresters and distribution fuse cutouts. In so far as the authors are aware, this is the first published information on transient recovery voltage tests on rural distribution systems and the correlation therewith of transient analyzer results.