Complex Distribution System Research Articles

Layered Model Algorithm and its Application in Fault Detection of Power Distribution Network

In the case that a single fault occurs on a power feeder in the one-source distribution system, the directional layered model of the network which reflects the layered topological characteristic of the network was built up. Then a new algorithm for fault detection in power distribution network was proposed to locate the faulty sections in distribution feeder network. The algorithm itself as well as its program design is simple. It can be applied to complex distribution systems with multi-sources. It is proved correct by an example.

Impact of Pipe Roughness on Pumping Energy in Complex Distribution Systems

As water utilities undertake pipe rehabilitation and replacement programs, the increase in energy efficiency through the reduction of pipe roughness is often cited as an important driver. To assess the impact of roughness coefficient changes associated with pipe rehabilitation, energy calculations were made using the hydraulic model for a large water distribution system. For a given flow rate, improving pipe roughness resulted in an energy savings from 0.70% to -0.20% and the results were highly dependent on the specific pipes that were replaced or rehabilitated. This approach can be used by water utilities to effectively target pipe rehabilitation activities.

Transient Behavior in Complex Distribution Network: A Case Study

Water distribution systems typically contain large numbers of pipes joining sources of supply to consumers; in addition they include a number of ancillary devices such as pumping stations, valves, storage reservoirs and surge suppression devices. These ancillaries and potential flow control points create systems with complex, varied dynamic conditions. Presented here are the results of a field monitoring case study that evidences propagation of transients within complex distribution system. The outcomes test the common assumption that damping and dissipation of transient occurs due to system complexity while travelling through a network. Ultimately such work improves understanding of dynamic pressure behaviors in complex networks which may help assess vulnerability to transients.

Improved Algorithm for Complex Distribution System Reliability and its Programming

In this paper, a new kind of recursive algorithm has been raised. It optimized the distribution network system reliability calculations, improved some efficiency, and met the user's needs closely. This algorithm needs no network equivalence process,has no complex principle and brings no difficulty to programming.Through its failure analysis, can be more easily identify key equipment of distribution systems for customers to adjust. This algorithm can easily cooperate with fault reconfiguration.No adjacency matrix and special chain table will be formed during searching procedure; it takes advantage of basic table of node data and branch data to do searching work, and easily to get access with field data. The algorithm uses recursive search also reduces programming greatly.

On the Reclose Operation of Superconducting Fault Current Controller for Smart Power Grid With Increasing DG

At present, the operation of protection coordination in a complex and uncertain power distribution system is satisfied through the use of a recloser and fuse. Due to the increased adoption of renewable energy resources, distributed energy resources as well as expanded electric transportation and dynamic demand response technologies in the power industry confront significant challenges during grid operations. As a result, protection coordination may be broken due to an increase in the current level in a power system. In general, once the protection is well coordinated by a fault current controller (FCC), the previously installed recloser on the existing power distribution system becomes useless because the FCC plays the role of the recloser. In this work, we propose an operating strategy of protection coordination for the FCC, which is capable of replacing the recloser in an environment where various types of distributed generation are introduced simultaneously due to the proliferating demand of renewable energy sources. Specifically, the suggested method based on PSCAD/EMTDC is investigated.

Reliability evaluation of ring and triple-bus distribution systems – General solution for n-feeder configurations

Reliability of power distribution schemes can always be improved at the expense of cost and size. The addition of extra paths proves to increase the continuity of supply but it adds more complexity to the system and the system structure may become very complex. In complex distribution system, there are several difficulties in reliability evaluation: reliability, availability and MTBF. Subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient and reliability test sample sizes tend to be small. Hence, simplification for the reliability inputs, electrical parameters and load data are needed.In this paper, a simple reliability-oriented method to calculate some complex distribution system reliability such as ring and triple-bus systems is presented. The major purpose is to simplify the reliability inputs, electrical parameters and load data. The simplification assumes that the repair time here is a random variable, and certain values of repair times are usually so small that can be neglected at each load point. Therefore complete reliability analysis with repair time omission and modified availability (reliability) and unavailability (h/year) can be obtained at each load feeder point using the simple methods of probability and the theory of sets. This approach is dealt with in this paper and a general formula for calculation of n-feeder ring-bus reliability is developed and applied to some practical distribution schemes.In an n-feeder ring-bus system, it is found that the reliability of each feeder is decreased by increasing the number of the outgoing feeders, so it is recommended that the total number of the outgoing feeders in this scheme should be carefully decided.A meshed network (triple-bus scheme), which makes it possible to serve the consumers from three sources is also considered. With this scheme, the reliability of the outgoing feeders is largely improved as compared with the ring-bus system.

Protection Technique for Complex Distribution Smart Grid Using Wireless Token Ring Protocol

Distributed generation is expected to increase sharply as more and more renewable are integrated to power system with the realization of smart grid, consequently complex distribution smart grid is given. The traditional protection devices cannot be able to protect complex power system configuration due to many fault current loops will feed the fault point. Relays based on standalone decisions cannot provide reliable and correct action when used on a complex distribution system. This paper proposes new protection philosophy using wireless technology. Data sharing among relays to obtain reliable and accurate decision are introduced. Wireless Token Ring Protocol (WTRP) as a wireless local area network (LAN) protocol inspired by the IEEE 802.4 Token Bus Protocol is used for data sharing. WTRP is selected to improve efficiency by reducing the number of retransmissions due to collisions. WTRP architecture and protocol are described to verify operation. MATLAB simulation program is used to simulate the data exchange protocol between relays in a ring for a specified amount of time.

Modelling formation of disinfection by-products in water distribution: optimisation using a multi-objective evolutionary algorithm

Research Article| May 01 2012 Modelling formation of disinfection by-products in water distribution: optimisation using a multi-objective evolutionary algorithm Mohanasundar Radhakrishnan; Mohanasundar Radhakrishnan 1Department of Urban Water Supply and Sanitation, UNESCO-IHE Institute for Water Education, Delft, The Netherlands E-mail: Mohanasundar@gmail.com Search for other works by this author on: This Site PubMed Google Scholar Assela Pathirana; Assela Pathirana 2Department of Water Science and Engineering, UNESCO-IHE Institute for Water Education, Delft, The Netherlands Search for other works by this author on: This Site PubMed Google Scholar Kebreab Ghebremichael; Kebreab Ghebremichael 3Patel School of Global Sustainability, University of South Florida Search for other works by this author on: This Site PubMed Google Scholar Gary Amy Gary Amy 1Department of Urban Water Supply and Sanitation, UNESCO-IHE Institute for Water Education, Delft, The Netherlands4King Abdullah University of Science and Technology, Saudi Arabia Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2012) 61 (3): 176–188. https://doi.org/10.2166/aqua.2012.179 Article history Received: November 03 2010 Accepted: March 09 2012 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Mohanasundar Radhakrishnan, Assela Pathirana, Kebreab Ghebremichael, Gary Amy; Modelling formation of disinfection by-products in water distribution: optimisation using a multi-objective evolutionary algorithm. Journal of Water Supply: Research and Technology-Aqua 1 May 2012; 61 (3): 176–188. doi: https://doi.org/10.2166/aqua.2012.179 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Concerns have been raised regarding disinfection by-products (DBPs) formed as a result of the reaction of halogen-based disinfectants with DBP precursors. In order to appreciate the chemical and biological tradeoffs, it is imperative to understand the formation trends of DBPs and their spread in the distribution network. However, the water at a point in a complex distribution system is a mixture from various sources, whose proportions are complex to estimate and requires advanced hydraulic analysis. To understand the risks of DBPs and to develop mitigation strategies, it is important to understand the distribution of DBPs in a water network, which requires modelling. The goal of this research was to integrate a steady-state water network model with a particle backtracking algorithm and chlorination as well as DBPs models in order to assess the tradeoffs between biological and chemical risks in the distribution network. A multi-objective optimisation algorithm was used to identify the optimal proportion of water from various sources, dosages of alum, and dosages of chlorine in the treatment plant and in booster locations to control the formation of chlorination DBPs and to achieve a balance between microbial and chemical risks. biological risk, chemical risk, disinfection by-products, genetic algorithm, multiple objective optimisation, particle back tracking algorithm This content is only available as a PDF. © IWA Publishing 2012 You do not currently have access to this content.

Classifier System and Co-evolutionary Hybrid Approach to Restoration Service of Electric Power Distribution Networks

The method proposed by the author is intended for assistance in decision-making (concerning changes of connections) by operators of complex distribution systems during states of malfunction (particularly in the events of malfunctions, for which the consequences encompass extended parts of the network), through designation of connection action scenarios (creating substitute configurations). It is the use by the classifying system working with the co-evolution algorithm that enables the effective creation of substitute scenarios for the Medium Voltage electric power distribution network. The author also completed works concerning the possibility of using cooperation of the evolutionary algorithm and the co-evolutionary algorithm with local search algorithms. The method drawn up may be used in current systems managing the work of distribution networks to assist network operators in taking decisions concerning connection actions in supervised electric power systems.

Spatio-temporal assessment of food safety risks in Canadian food distribution systems using GIS

While the value of geographic information systems (GIS) is widely applied in public health there have been comparatively few examples of applications that extend to the assessment of risks in food distribution systems. GIS can provide decision makers with strong computing platforms for spatial data management, integration, analysis, querying and visualization. The present report addresses some spatio-analyses in a complex food distribution system and defines influence areas as travel time zones generated through road network analysis on a national scale rather than on a community scale. In addition, a dynamic risk index is defined to translate a contamination event into a public health risk as time progresses. More specifically, in this research, GIS is used to map the Canadian produce distribution system, analyze accessibility to contaminated product by consumers, and estimate the level of risk associated with a contamination event over time, as illustrated in a scenario.

Suitability of Chlorine Bulk Decay Models for Planning and Management of Water Distribution Systems

Effective disinfection planning and management in large, complex water distribution systems requires an accurate network water quality model. This model should be based on reaction kinetics, which describes disinfectant loss from bulk water over time, within experimental error. Models in the literature were reviewed for their ability to meet this requirement in real networks. Essential features were identified as accuracy, simplicity, computational efficiency, and ability to describe consistently the effects of initial chlorine dose, temperature variation, and successive rechlorinations. A reaction scheme of two organic constituents reacting with free chlorine was found to be necessary and sufficient to provide the required features. Recent release of the multispecies extension (MSX) to EPANET and MWH Soft's H2OMap Water MSX network software enables users to implement this and other multiple-reactant bulk decay models in real system simulations.

Near-optimal scheduling of device activation in water distribution systems to reduce the impact of a contamination event

This paper proposes an innovative procedure for identifying, in the event of accidental or intentional contamination of a water distribution system, the optimal scheduling of activation of a pre-selected set of flow control devices which will serve to minimise the volume of contaminated water consumed by users after the detection of the contaminant in the system. The constraints are represented by the number of available response teams and the maximum speed at which these teams can travel along the roadway. The optimal scheduling of device activation is sought by means of an optimisation process based on a genetic algorithm (GA) which interacts with a mixed integer linear programming (MILP) solver in order to ensure the feasibility of the scheduling identified. The optimisation procedure is coupled to a hydraulic and quality simulator, which enables a calculation of the volumes of contaminated water consumed by users, and a dynamic cache memory, which, by storing information on the system's behaviour as the optimisation process progresses, serves to limit the computational times. The application of the procedure to a highly complex real water distribution system shows that the optimisation process is robust and efficacious and produces a smaller volume of contaminated water consumed by the users than when the activation of all the devices was completed in the shortest amount of time.

Micro-light distribution system via optofluidic cascading prisms

This article reports a micro-light distribution system realized by altering the reflective indices of two optofluidic cascading prisms. Different micron scale light distribution configurations can be tuned via the imposed flow rates of the microfluidic mixers. The variable optical interface’s reflectivity of the cascading prisms is based on the tuning of refractive indices of micromixed fluids within the cascading prisms. The microscale light distribution is achieved via total internal reflection and partial refraction occurs at the fluid–solid optical interfaces. 1 × 3 light switching denotes one optical inlet while the light can be guided via any one of the three optical outlets. The 1 × 3 light switching capability is demonstrated. The light splitting capability to achieve different proportion of light power distribution is also demonstrated and characterized. The optofluidic cascading prisms are integrated with micromixer, prolonging the working life of the optical compartment considerably as the fluids are only consumed when optical tuning is required. The proposed technique eliminates the disadvantage of optofluidic compartments based on liquid–liquid interfaces as liquid–liquid interface possess weaker mechanical stability than solid–liquid interface. The proposed design also does not require continuous supply of fluids as in optofluidic compartments based on liquid–liquid interfaces. The optofluidic cascading prisms can be cascaded further to form a complex planar light distribution system for seamless light distribution in lab-on-a-chip excitation and sensing applications.

Voltage Sag Data Utilization for Distribution Fault Location

Fault location in distribution systems is an important function for outage management and service restoration directly impacting feeder reliability. In this paper, a fault location method based on matching calculated voltage sag data and data gathered at some nodes in the network is proposed. A method for characterization of voltage sags is utilized to reduce amount of transferred data. The proposed method can pinpoint fault location precisely, and is applicable to any complex distribution systems with load taps, laterals, and sub-laterals, single-phase loads, as well as networks with heterogeneous lines. The performance of the proposed method is demonstrated on the IEEE 123-node distribution test system via computer simulations in Alternate Transients Program software.

On the usage of artificial neural networks in chlorine control applications for water distribution networks with high quality water

Artificial neural network (ANN) methodology has found some recent applications as efficient control tools for satisfying free residual chlorine ( FR C) levels at critical locations of water distribution systems. This particular research was started to critically investigate the potential and applicability of the ANN approach as a tool for controlling FRC levels for complex water distribution systems supplied by high quality waters with low chlorine demands. Konyaalti Water Distribution System, operated by Antalya Water and Wastewater Administration, Turkey, has been selected as a pilot. The selected system is complex in structure and supplied with raw water which has high quality and low decay rate of chlorine. The study has shown that ANN models with high predictive power and precision can be developed for such water distribution systems, and that these models can be utilized for forecasting purposes. The data for model building should be collected properly if the developed A NN models are to be utilized as control instruments for FRC levels within water distribution systems.

Simulation modelling of complex distribution systems

In many lines of business distribution enterprises take over the burden of synchronization of the demand and supply aspects of the supply chain. Their part increases especially on very dynamic markets, with variable demand and a short product life cycle. Then one of the strategy is to postpone production and shift its last stage from the part of industrial companies to distributional enterprises. The article will discuss the issue of network configuration for the needs of complex realization of non-standard orders. The investigation has been conducted on the basis on enterprises designing interorganizational relations in networks of cooperating enterprises.

Negative pressures in full-scale distribution system: field investigation, modelling, estimation of intrusion volumes and risk for public health

Abstract. Various investigations encompassing microbial characterization of external sources of contamination (soil and trenchwater surrounding water mains, flooded air-valve vaults), field pressure monitoring, and hydraulic and transient analyses were conducted in the same distribution system where two epidemiological studies showing an increase in gastrointestinal illness for people drinking tap water were conducted in the 1990's. Interesting results include the detection of microorganisms indicators of fecal contamination in all external sources investigated but at a higher frequency in the water from flooded air-valve vaults, and the recording of 18 negative pressure events in the distribution system during a 17-month monitoring period. Transient analysis of this large and complex distribution system was challenging and highlighted the need to consider field pressure data in the process.

Managing Distribution in Supply Chain Networks

This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additi...

Optimal Operation of Complex Water Distribution Systems Using Metamodels

Optimization of large and hydraulically complex water distribution systems (WDSs) is computationally expensive as simulation models are required to evaluate the performance of solutions to the problem at hand. Metamodels can act as a surrogate or substitute for these simulation models and provide significant speed-ups in the optimization process. The application of metamodels in the field of WDS optimization has been limited to date, and little guidance has been given in terms of constructing metamodels for hydraulically complex systems. While it is relatively straightforward to obtain satisfactory metamodel approximations to simulation models of simple WDSs, this is not necessarily the case for more complex networks. In order to reduce the complexity of the relationship that is to be approximated by the metamodels, a number of factors have to be considered, including the complexity of the hydraulic simulation model, the complexity of the decision space, and the locations at which outputs are required fro...

A multi-objective approach for detecting and responding to accidental and intentional contamination events in water distribution systems

The protection against contamination events in water distribution systems involves two distinct phases: detection of the presence of a contaminant and implementation of actions to isolate and/or expel it rapidly. The problem of detection is confronted by installing a series of monitoring stations, strategically placed across the distribution system and consisting of sensors to detect the presence of contaminants. The actions to be implemented may include operations on distribution system devices (valves and hydrants) or injection of reagents to eliminate the contaminant, or simply alert users. The procedure proposed here attempts to address the problems related to the two phases by means of two consecutive optimisation processes, both of them performed off-line and assuming a specific 24-hour water demand sequence in each network node, whereas the accidental/intentional injection of contaminant can occur in any node and at any hour of the day. With reference to this vast range of possible injection scenarios, the first multi-objective optimisation process defines the position of a pre-selected number ns of sensors across the distribution system in order to minimise the expected percentage of undetected contamination events and the expected volume of contaminated water consumed up to the beginning of the response operations following detection. A single configuration of stations is then selected from the Pareto front produced by this optimisation process (‘knee point’ of the Pareto front). At the end of this first optimisation process and with reference to the selected set of sensors, a potentially contaminated area in the network is associated to each sensor for each sub-period of the day. The second multi-objective optimisation process is then aimed to identify, with reference to each station and sub-period, and thus inside the corresponding potentially contaminated area, the hydrant-opening and valve-closing operations to be carried out in order to minimise both the number of operations and the expected volume of contaminated water consumed between the beginning of the response operations and the disappearance of the contaminant, assuming the availability of an unlimited number of response teams. Once these devices have been identified (‘knee point’ of the Pareto front relevant to the second optimisation process), an a posteriori analysis is performed to determine the sequence in which they should be activated based on the number of response teams actually available. In these optimisation processes, a hydraulic and quality simulator (EPANET) is linked to a multi-objective genetic algorithm (NSGA-II) in order to compute the value of the objective functions of the problem across different contamination scenarios. The results obtained applying the procedure to a real and complex water distribution system have shown it to be a robust and effective method for reducing the impact on the population.