Search results for "Distribution networks"

Pumps as turbines (PATs) in water distribution networks affected by intermittent service

2013

A hydraulic model was developed in order to evaluate the potential energy recovery from the use of centrifugal pumps as turbines (PATs) in a water distribution network characterized by the presence of private tanks. The model integrates the Global Gradient Algorithm (GGA), with a pressure-driven model that permits a more realistic representation of the influence on the network behaviour of the private tanks filling and emptying. The model was applied to a real case study: a District Metered Area in Palermo (Italy). Three different scenarios were analysed and compared with a baseline scenario (Scenario 0 – no PAT installed) to identify the system configuration with added PATs that permits th…

Leaks Analysis in Pipeline Systems by Means of Optimal valve Regulation

1999

Direct solution of compensated radial distribution networks with constant impedance/current loads

2009

In this paper, a methodology to solve radial distribution networks, with constant current and/or impedance loads as well as shunt capacitor banks, is proposed. The techniques currently available to solve such systems are based either on iterative methods or on the bus impedance matrix. In both cases, the elaboration times are quite high since these are related, for iterative methods, to the overall number of iterations, and, for those methods based on the impedance matrix, to the inversion of the admittance matrix. The method developed here is the extension of a technique that is valid to solve networks made of impedances with one supply point. The methodology can also be applied in the sol…

Impact of diffusion and dispersion of contaminants in water distribution networks modelling and monitoring

2019

Abstract In recent years, there has been a need to seek adequate preventive measures to deal with contamination in water distribution networks that may be related to the accidental contamination and the deliberate injection of toxic agents. Therefore, it is very important to create a sensor system that detects contamination events in real time, maintains the reliability and efficiency of measurements, and limits the cost of the instrumentation. To this aim, two problems have to be faced: practical difficulties connected to the experimental verification of the optimal sensor configuration efficiency on real operating systems and challenges related to the reliability of the network modelling …

Prosumer’s impact on low voltage distribution networks

2019

The use of renewable energy, within nowadays energy policy, has increased considerably all over the world in order to respond to the increasing energy consumption and to reduce the environmental impact of the electricity generation. At the beginning, the relatively low penetration levels of distributed generation does not produce problems, however, the nowadays massive increase of local power generation have led to new integration challenges in order to ensure the reliability and quality of the power supply. This paper also highlights some aspects regarding the use of the active distribution networks of low voltage to which electric energy producers are connected-the prosumers: advantages a…

Networks of Manufacturers and Retailers

2005

We study the endogenous formation of networks between manufacturers of differentiated goods and multi-product retailers who interact in a successive duopoly. Joint consent is needed to establish and/or maintain a costly link between a manufacturer and a retailer. We find that only three distribution networks are stable for particular values of the degree of product differentiation and link costs: (i) the non-exclusive distribution and non-exclusive dealing network in which both retailers distribute both products is stable for intermediate degree of product differentiation and small link costs; (ii) the exclusive distribution and exclusive dealing network in which each retailer distributes a…

Decoupled solution of radial and weakly meshed distribution networks through a backward method

2008

A methodology for the analysis of radial or weakly meshed distribution systems supplying voltage dependent loads is developed. The solution process is iterative and, at each step, the loads are simulated by means of impedances. The network is divided into two sub-networks which must be solved separately and sequentially; in the first, named RP-net, only the lines resistances and the loads shunt equivalent resistances are considered; in the second, named XQ-net, only the lines reactances and the shunt equivalent reactances are taken into account. After a brief presentation of the b/f method, which is currently the most commonly used technique to solve distribution networks, the proposed meth…

An Integrated System for Efficient Management of Distribution Networks: The System's Architecture and the Telecommunication Infrastructure

2006

Modern distribution systems must keep up with high power quality standards due to the new regulations of the European Community and of the different national legislations. Efficient faults management is one of the basic tasks utilities must accomplish and this objective can be attained if and only if automation is present and efficient diagnostic procedures have been implemented in the centralized or distributed units all over the network. In this paper, the architecture of an integrated system for management of modern distribution systems is presented. The system includes routines for normal on-line optimal operation of distribution systems and for outage management, the latter including f…

Who Uses Intermediaries in International Trade? Evidence from Firm-level Survey Data

2013

The present paper uses data from the World Bank Enterprise Survey conducted in Turkey in 2005 to shed light on the firms that use intermediaries in international trade. It lends robust empirical support to recent theories which suggest that indirect exporters are mostly small firms that are not profitable enough to cover the high fixed costs of building an own distribution network abroad. Manufacturers who develop new products are more likely to use trade intermediaries, as are firms that produce low-quality goods. In contrast, neither foreign ownership nor credit constraints are correlated with the choice of export mode. Moreover, firms that rely on trade intermediaries to sell their goods…

Evaluation of the Water Scarcity Energy Cost for Users

2013

Abstract: In systems experiencing water scarcity and consequent intermittent supply, users often adopt private tanks that collect water during service periods and supply users when the service is not available. The tank may be fed by gravity or by private pumping stations depending on the network pressure level. Once water resources are collected, the tank can supply users by gravity if it is located on the rooftop or by additional pumping if underground. Private tanks thus increase the energy cost of the water supply service for users by introducing several small pumping structures inside the network. The present paper aims to evaluate this users’ energy cost for different private tank con…