Search results for "distribution networks"

A Compensation Based Method to Model PV Nodes in Backward/Forward Distribution Network Analysis

2007

PurposeThis paper proposes to identify a new model of the fixed voltage nodes (PV nodes) for medium voltage distribution systems analysis. The model is used within backward/forward (b/f) analysis method applied to solve radial and weakly meshed systems.Design/methodology/approachThe model is based on the compensation currents method for multi‐port systems which has been extensively used, within b/f analysis methods, to take into account the presence of meshes and PV nodes.FindingsTest results prove the approach to be more efficient and precise than previous methodologies and put into evidence the good performance of the proposed model in terms of speed and convergence properties.Research li…

Evaluation of statistical sampling for the assessment of residential consumption totals in water distribution networks

2014

The paper provides insights into stratified sampling, a standard statistical technique that may be employed to assess domestic water use in water distribution networks. The basic idea is to use only a few meters to provide inference on the total water consumption of a network or of a district metered area through the knowledge of some additional stratification variables, such as household typology, size and occupants number. Since any sampling procedure assumes that the variance of the variable at stake is known, either a suitable amount of past consumption data is necessary, or a specific preliminary survey must be carried out, in order to define the sampling plan. An application with real…

A mathematical model to evaluate apparent losses due to meter under-registration in intermittent water distribution networks

2013

Apparent losses consist of water volume drawn from the network, consumed by users but not paid for. Those due to water meter under-registration were evaluated by means of a mathematical model able to analyse the complexity of intermittent supply systems with private tanks. This supply scheme is very common in the Mediterranean area where unexpected water shortage often happens and intermittent water supply is a common practice. In order to analyse such complex systems, a demand model, reproducing the effect of private tanks, and an apparent losses module were developed and coupled with an hydraulic network model based on the Global Gradient Algorithm (GGA). In distribution networks pressure…

A Package for the Analysis of Automated MV Distribution Networks

2005

Secondary substation power line communications for medium voltage smart grids

2012

In this paper a performance analysis is carried out, in order to evaluate the possibility to employ power line communication (PLC) between secondary substations of a medium voltage (MV) distribution networks in a smart grid. The study is focused on the analysis of PLC technologies and the evaluation of the influence quantities on the communication performance in the most common case of by-pass connection at MV bus-bars of secondary substations. Different quantities have been analyzed as modulation techniques, requested bandwidth and bitrate, coupling device and system attenuation versus frequency in order to find the best solution for a reliable communication system. A complete model of a r…

Energy Recovery in Water Distribution Networks. Implementation of Pumps as Turbine in a Dynamic Numerical Model

2014

In complex networks characterized by the presence of private tanks, water managers usually apply intermittent distribution, thus reducing the water volumes supplied to the users, or use Pressure Reduction Valves (PRV) for controlling pressure in the network. The application of Pump As Turbines (PATs) appears as an alternative and sustainable solution to either control network pressure as well as to produce energy. In the present paper, the hydrodynamic model, already presented by De Marchis et al. (2011) was further developed introducing the dynamic analysis of PATs. The model was applied to a district of Palermo network (Italy) characterized by intermittent distribution and by inequities a…

A new model for a safety analysis in a system of earthing systems interconnected through bare‐buried conductors

2009

PurposeThe purpose of this paper is to present a mathematical model for studying the effects of the interconnection through bare‐buried conductors (BBC) of the secondary substations' earthing system of an urban area.Design/methodology/approachThe developed methodology is based on three main points: the solution of the transmission lines' equations for the formulation of a lumped parameters model of a BBC considering the conductive effect; the division of the distribution network into simpler sub‐systems; and the calculation of all the voltages and currents of the medium voltage (MV) network and of the earthing systems using a multiport approach.FindingsThe methodology has been applied to va…

Investigating the effect of distributed generators on traditional protection in radial distribution systems

2013

The recent changes in power network structure, development in green energy technologies and increased attention on environmental concerns have led to increase the installation of renewable energy based distributed generations (DG) in distribution networks. The increasing penetration of distributed generation in the distribution power system creates new technical and economical challenges; protection is one important topic of these challenges. High penetration of DG will have unfavorable impact on the traditional protection methods; the impact depends on the number, location and size of injected DG. To ensure safe and selective protection devices coordination, the impact of DG should be take…

Planning Rehabilitation Actions on Water Distribution Networks in Condition of Data Scarcity

2011

The paper shows a viable approach to the selection of water networks rehabilitation actions, in condition of data scarcity and uncertainty, based on the use of four concise performance literature indices, allowing the analysis and identification of efficient, reliable and robust rehabilitation alternatives, even if assessed on the basis of a relatively small amount of data. A promising statistical sampling method of water consumptions is also described, that may be fruitfully employed within the proposed approach for drafting water balances at network district scale in order to quantify the extent of leakages. The illustrated case study shows that the selected indices are capable to describ…

Service restoration in compensated distribution networks using a hybrid genetic algorithm

1998

In this paper a genetic algorithm (GA) based approach to the service restoration (SR) problem in automated distribution networks is presented. Normal operation within the network comprises both automatic reconfiguration and compensation so as to reduce power losses, allow load balancing and improve the voltage profile. In the restorative state, the reconfiguration is performed together with compensation, taking mainly into account the load supply requirement and secondarily, the losses reduction requirement. After a general discussion on the restoration problem together with a short review of recent papers on the topic, a solution strategy is proposed. Then, a short account about classical …