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This work presents the modelling fundamentals to study the dynamics of inverter-based resources (IBRs) in weak distribution grids and derive disturbance performance characteristics describing how they should behave under different conditions. More specifically, with respect to small-signal disturbances we study the possible voltage violations following frequency response from IBRs due to low system strength and also propose specific design requirements for IBR d-q current control to guarantee a stable response. In the context of large-signal disturbances, we highlight how active power-voltage control may not be effective due to a delay imposed by the physical features of the distribution network. Further, we mathematically discuss how IBR reactive power control could enhance its phase-locked loop stability. The proposed disturbance performance characteristics are then integrated into the IBR converter control via a novel voltage-priority reference generation strategy. Simulation results on a real Australian network show the efficacy of the proposed operational and control design requirements, and highlight possible unexpected active/reactive power interactions in weak distribution grids.

Metal artifacts from the Paleometal Epoch (ca. 1100 BC–400 AD) of the Primorye (Russian Far East) have shed new light on the introduction of the earliest bronzes into the Pacific coastal areas of prehistoric Eurasia. However, little is known about raw material circulation and the role of metal in the context of inter-regional exchange. This paper investigates 12 copper artifacts from major Paleometal settlements using alloy composition, trace elements, and lead isotopes to explore the metal sources and distribution networks. The results suggest that most objects are made of a copper-tin alloy, but some have arsenic as a significant minor element . Geologically, copper is unlikely to have come from local ore sources, but rather from the Liaoxi corridor and Liaodong Peninsula in Northeast China. This may indicate an inland route of metal trade across Northeast China or alternately, a coastal route via the northern Korean Peninsula. Archaeologically, the combined study of artifact typology and chemistry indicates two possible origins for the metal: the Upper Xiajiadian culture in Northeast China and Slab Grave culture in Mongolia/Transbaikal. Remarkably, the connection with Upper Xiajiadian communities parallels the transport route along which millet agriculture spread from Northeast China to the Primorye during the Neolithic.

This paper presents the design proposal of distribution network monitoring unit based on dual-DSP. A detailed description of the hardware structure about the device is introduced which including signal scheduling, SPI communication, the serial human-computer communication and network communication. Additionally, the paper describes the software process about the master and slave DSPs. Then the analog precision test and the protection response test are carried out. The result shows that the design proposal is correct.

Elektrikli araçların (EA) sayısı arttıkça, EA’ların şarj yükünün güç dağıtım şebekelerine ilave yük bindireceği ve sorunlar yaşanabileceği güncel tartışılan bir konudur. EA’ların şarj maliyetini şebekenin yükünün düşük olduğu saatlere kaydırmaya yönelik akıllı mekanizmalar bir çözüm olarak değerlendirilmektedir. Bu çalışmada, EA’ların şebekeye entegrasyonu sonrası bu tür ihtiyaçlar ve çözümler analiz edilmiştir. Bu amaçla, 2030 yılında Türkiye’de sayıları önemli ölçüde artması beklenen EA’ların şebekeye etkilerine yönelik olarak, pilot bir dağıtım şebekesinde, senaryo bazlı simülasyonlar gerçekleştirilmiştir. EA’ların pilot dağıtım şebekesi üzerindeki etkilerini değerlendirmek için, ilk önce hedef yıl olan 2030 için bir referans şebeke modeli (EA şarj yükü olmayan) geliştirilmiştir. Daha sonra, farklı teknolojilerdeki (yavaş ve hızlı şarj) EA şarj noktaları, yoğunlukla evlerde şarj ve yoğunlukla işyerlerinde ve kamusal alanlarda şarj senaryoları için ayrı ayrı olmak üzere, bu referans şebeke modeline ilave edilmiştir. Rastgele değişkenler olan EA’ların şarj istasyonlarına varış zamanı ve varış zamanında şarj durumu (SOC) stokastik yaklaşımlar ile modellenmiştir. EA’ların şebekeye entegrasyonunun etkileri, ekipmanların (transformatör ve hatlar) yıllık doluluk oranı (%), aşırı yüklenme (%) ve aşırı gerilim düşümü (%) açılarından incelenmiştir.

Polyethylene (PE) gas pipes are introduced in Algeria in 1978 to substitute the old pipelines made by copper, steel and cast iron. These later were used for the distribution of natural gas with medium working pressure of four bars. In this study, the polyethylene pipes were extracted from the Algerian distribution gas network in order to study their characteristics after more than 30 years of use. Two different pipe diameters (O63 and O125) with different ages of use were characterized according to the specifications on the EN1555-2 standard. The dimensional, physical and mechanical tests were performed with the same parameters as a newly produced pipe. The results showed that most of the characteristics are still fitting the EN 1555-2 specifications except for the density and the oxidative induction time. These two later will be considered as two basic parameters for the future studies of the polyethylene aging.

La finalidad del articulo es presentar un diseño de conversión de redes de distribución de energía eléctrica aéreas públicas en medio y bajo voltaje, a redes de distribución de energía eléctrica subterránea en los alrededores de la Universidad Politécnica Salesiana sede Guayaquil, permitiendo la modernización del sistema eléctrico público, prevención de accidentes, cortes de energía por sistemas deteriorado y mejorar el impacto visual de la zona. Para la elaboración del proyecto se realizó el levantamiento de información del sistema eléctrico existente, se determinó la demanda actual y la demanda proyectada, además se estimó el consumo por cocina de inducción para cada usuario. Se realizó el estudio lumínico, el diseñó del sistema de distribución en medio voltaje, los centros de distribución de carga, centros de transformación, conductores y protecciones necesarias. De acuerdo a las proyecciones realizadas, el diseño planteado alimentará la carga actual y la que se incrementará en los próximos 10 años.

Charging stations not only provide charging service to electric vehicles (EVs), but also integrate distributed energy sources. This integration requires an appropriate planning to achieve the future sustainable distribution network. Real EV charging demand is stochastic and affected by many uncertainties, which pose challenges to the planning of a charging station. This study presents a stochastic planning model of the EV charging station with photovoltaic (PV), battery and transformer, mainly considering the uncertainties from charging demand and PV power generation. Firstly, a comprehensive EV charging demand model is established through reflecting the coupling among the EV stochastic charging behaviour, charger specifications and EV charging assignment model. Then, the planning model is formulated to minimise the total cost of the charging station, where the uncertainties arising from EV charging are addressed in various constraints. Using this model, the optimal sizing of the charging station is determined, together with the associated optimal operation strategy. Finally, the effectiveness of the proposed model is validated by multiple case studies.

Küçükkoç, İbrahim (Balikesir Author), This paper addresses to the facility location problem of ammunition stores considering the design of distribution network from stores to geographically dispersed army forces. The problem is to determine the construction sites of the ammunition stores among candidate sites and to give the decision on how many stores will be built from which kind. The problem also contains designing of a distribution network to concurrently determine the amounts of several military equipment transported from stores to army forces. A mathematical model is proposed to minimize the cost of the whole system, caused by the construction of the ammunition stores and the transportation of different equipment in diverse quantities from stores to dispersed army forces. The model is then improved progressively and several variants are presented to reflect the real-world conditions through a case study. Numerical results obtained from solving the case study using the proposed models coded in General Algebraic Modelling System (GAMS) are exhibited. The effect of the size of problem specific parameters on the model execution time is also investigated via experimental tests. The results demonstrate the promising problem-solving capacity of the proposed models, which can be applied practically.

© 2022 IEEE.This paper presents a novel two-stage optimization approach for the optimal sizing of static var compensators and their operational management to maximize the photovoltaic integration capacity of distribution systems. In the first stage, the optimal locations for fixed size photovoltaic (PV) systems are determined to minimize the sum of total voltage violations. In the second phase, the size of the PV units are resized and the optimal size, number, location, and operating strategy of the SVC units are determined to maximize PV hosting capacity. In both phases, the Marine Predators algorithm is used for the solution optimization equations. The performance of the proposed approach and solution method is validated on modified 33-node and 141-node radial distribution networks. The results are discussed from the point of view of the maximum hosting capacity and compared with the Grey Wolf optimization and Whale Optimization algorithms in terms of computational performance.

A primary requirement of a modern electric power system is reasonable ability to satisfy the customer load requirements. Electric utilities involve generation, transmission, and distribution facilities each one of which contributes its own inherent difficulties to the problem of satisfying customer requirement. A power system should be designed and expanded the facilities in order to perform its intended function with a reasonable risk. With increasing the electrical energy demand and the potential of disruption that may occur in the system, the distribution system must have high reliability and continues supply to customer. In this case, the reliability of the distribution system needs to be evaluated by monitoring and analyzing the level of distribution system failure in a certain period of time. A study on a practical distribution system with application of automatic circuit reclosers (ACRs) which plays an important role in enhancing the reliability index of system is presented. The reliability index assessment analyze the reliability index of the existing system before and after application of ACRs. From the simulation point of view, the system average interruption frequency index (SAIFI) is about 19.43% or decreased the failure frequent event from 11.4 failure/ customer.year to 9.25 failure/customer.year); while the momentary average interruption frequency index (MAIFI) has decreased from 6.72 failure/customer.year to 5.05 failure/ customer.year, or increase the reliability index of about 24.85%.

Corrosion deterioration is the predominant factor for a large number of cast iron (CI) water main breaks. The reliability of CI pipelines decreases overtime as corrosion growth on pipe wall...

Lowering the exergy content of heat required for heating purposes decreases the primary energy consumption. District heating systems are often an important link between facilities that generate heat with low exergy content and consumers. Exergetic efficiency of heat distribution is an important performance criterion in heat supply to consumers. It can serve as a criterion for optimization, towards a more sustainable distribution-network design and operation. This paper presents a methodology for an exergy-based distribution-network analysis in a district heating system. Criteria for performance evaluations are defined. They can be used to evaluate heat supply to different points in the network, or individual system components. A case study is performed on an existing district heating system. Energetic and exergetic efficiencies of supply lines are analyzed. Exergy destructions and exergy losses are studied. Large differences in efficiency of heat supply to different points in the network are discovered. Over-dimensioned parameters of the distribution network are investigated.

Budget distribution over water network segments is one of the challenges that face municipalities worldwide. Most water distribution networks (WDNs) are deteriorating, and thus they require...

This paper presents small signal stability analysis of distribution networks with electric springs (ESs) installed at the customer supply points. The focus is on ESs with reactive compensation only. Vector control of ES with reactive compensation is reported for the first time to ensure compatibility with the standard stability models of other components such as the interface inverter of distributed generators (DGs). A linearized state-space model of the distribution network with multiple ESs is developed which is extendible to include inverter-interfaced DGs, energy storage, active loads, etc. The impact of distance of an ES from the substation, proximity between adjacent ESs and the R/X ratio of the network on the small signal stability of the system is analyzed and compared against the case with equivalent DG inverters. The collective operation of ESs is validated through simulation study on a standard distribution network.

This paper presents a new method to determine the optimal number and locations of autorecloser and sectionalizer switches (AR/S) in distribution networks. The costs of AR/S investment, switch maintenance, and undistributed energy as well as reliability coefficients are considered in the objective function. Reliability parameters such as SAIFI, SADI, MAIFI, and ENS are evaluated in the case study system. As a new method, the weights of the reliability parameters are obtained by decision-makers using the analytical hierarchy process (AHP). The optimal size, type, and location of automatic switches are determined by minimizing the objective function using the particle swarm optimization (PSO) algorithm. The effectiveness of the proposed method is tested by implementing it on two feeders of Isfahan's electric distribution network. The results indicate the efficiency and applicability of the proposed method.

This paper proposes a novel three-stage robust inverter-based voltage/var control (TRI-VVC) approach for high photovoltaic (PV)-penetrated distribution networks. The approach aims at coordinating three different control stages from centralized to local VVC to reduce energy loss and mitigate voltage deviation. In the first stage, capacitor banks and an on-load tap changer are scheduled hourly in a rolling horizon. In the second stage, PV inverters are dispatched in a short time-window. In the third stage, the inverters respond to real-time voltage violation through local droop controllers. A new PV inverter model for voltage control is developed to support both the centralized var dispatch and the local var droop control. To address uncertain PV output and load demand, a robust optimization (RO) model is proposed to optimize the first two stages while taking into account the droop voltage control support from the third stage. A linearized distribution power flow model with power loss is developed and applied in the RO. The simulation results show high efficiency and robustness of the proposed TRI-VVC strategy. Ministry of Education (MOE) This work was supported in part by the Singapore Ministry of Education under an Academic Research Fund Tier 1 Project, and in part by the China Southern Power Grid Company under Project WYKJ00000027. The work of C. Zhang was supported by Australian Government Research Training Program Scholarship. The work of Y. Xu was supported by the Nanyang Assistant Professorship Award from Nanyang Technological University, Singapore. Paper no. TSG-00343-2017. (Corresponding author: Yan Xu.)

Uncertainty in power system planning problems can be categorized into two types: exogenous and endogenous (or decision-dependent) uncertainty. In the latter case, uncertainty resolution depends on a choice (the value of some decision variables), as opposed to the former case in which the uncertainty resolves automatically with the passage of time. In this paper, a novel stochastic multistage planning model is proposed that considers endogenous uncertainty around consumer participation in demand-side response (DSR) schemes. This uncertainty can resolve following DSR deployment in two possible ways: locally (at a single bus) and globally (across the entire system). The original formulation is decomposed with the use of Benders decomposition to improve computational performance. Two versions of Benders decomposition are applied: the classic version involving sequential implementation of all operational subproblems and a novel version, specific to problems with endogenous uncertainty, which allows for the parallel execution of only those operational subproblems that are guaranteed to have a unique contribution to the solution. Case studies on 11-bus and 123-bus systems illustrate the process of endogenous uncertainty resolution and underline the strategic importance of deploying DSR ahead of time.

In addition to the day-ahead congestion management in distribution networks, the real-time congestion management is very important because many unforeseen events can occur at the real operation time, e.g. loss of generation of distributed energy resources (DERs) or inaccurate forecast of energy consumption or production. Flexibility service from demand will be a good option to solve the real-time congestions if the cost of activating the flexibility service is fully addressed. This paper proposes a new method, namely “swap”, to employ the flexibility service from electric vehicles (EVs) and heat pumps (HPs) for real time congestion management. The swap method can maintain the power balance of the system and avoid the imbalance cost of activating the flexibility service. An algorithm for forming swaps through optimal power flow (OPF) and mixed integer linear programming (MILP) is proposed to implement the swap method. Case studies were carried out to validate the efficacy of the proposed swap method for real time congestion management and the proposed algorithm for forming swaps. The settlement process for the swaps in different markets is analyzed.

We study the charging control of plug-in electric vehicles in distribution networks with capacity constrained feeder lines. It is usually challenging to design an effective decentralized method to implement the optimal solution for the formulated constrained optimization problems due to the coupling relationship of charging behaviors on the constrained distribution network system. Alternatively, in this brief, in order to avoid possible overloading on the feeder lines, we propose a gradient projection-based decentralized method such that the step size is properly adjusted. We show that by applying the proposed method, the system converges and the implemented solution satisfies the capacity constraints of feeder lines. Simulation results show that the proposed method can effectively avoid possible overloads on the feeder lines in distribution networks.

DOI: 10.26650/electrica.2018.02248In this paper, simple approximate formulasare established to estimate active and reactive power losses in distributionnetworks. The developed formulas based on load profiles are derived fromElgerd’s power loss formulas. A simple model is also proposed to estimate theload profile while considering several parameters, such as the average loaddemand and the load limitations. Derivation of the load model and the lossformulas are presented along with their applications on two distributionnetworks. The results show that the loss formulas, which depend on the proposedload profile, can estimate the power losses in distribution networks with highprecision., DOI: 10.26650/electrica.2018.02248In this paper, simple approximate formulas are established to estimate active and reactive power losses in distribution networks. The developed formulas based on load profiles are derived from Elgerd’s power loss formulas. A simple model is also proposed to estimate the load profile while considering several parameters, such as the average load demand and the load limitations. Derivation of the load model and the loss formulas are presented along with their applications on two distribution networks. The results show that the loss formulas, which depend on the proposed load profile, can estimate the power losses in distribution networks with high precision.

The development of decentralized sources of power out of renewable sources of energies has been triggering far-reaching consequences for Distribution System Operators over the past decade in Europe. Our paper benchmarks across 23 European countries the impact of the development of renewables on the physical characteristics of power distribution networks and on their investments. It builds on a large spectrum of databases of quantitative indicators about the dynamics of installed capacity of renewable energy resources and the power generation out of them, electricity independence, quality of electricity distribution, smart grids investments, Network System Operators capital expenditures, length of the distribution networks, overall costs of power networks paid by private agents, and electricity losses, all in relation with the development of decentralized generation. The heterogeneity of these indicators across Europe appears to be wide notably because of physical constraints, historic legacies, or policy and regulatory choices. A cluster analysis allows for deriving six groups of countries that display statistically homogenous characteristics. Our results may provide decision makers and regulators with a tool helping them to concentrate on the main issues specific to their countries as compared to the European median, and to look for possible solutions in the experience of other clusters which are shown to perform better for some indicators.

Web and Internet technologies for education of university students and for engineering staff (continuing education) on electrical engineering are considered. The Web and Internet technologies form an important part in modern curricular as a subject for learning as well as a means of organization of education process. A set of specific subjects for students is presented.

In the near future, home energy management systems (HEMSs) will become common in reaction to time-varying pricing, and residential electricity customers’ striving to minimize their energy costs. However, if many residences connected to a common pole-top transformer are all optimizing their electricity consumption based on the same electricity tariff, their aggregated demand may result in large, short-lived peaks. Traditional demand peaks would be reduced since the electricity prices are high, but early morning (low price periods) demand peaks would be increased. Since high demand increases transformer temperatures and degrades their insulation, managing these peaks extends transformer life and reduces network upkeep costs. This paper presents an approach for managing the rollout of HEMSs on a distribution feeder. Several heuristic strategies for incentivizing customer adoption of HEMSs are investigated and compared to the optimal adoption strategy. A case study using representative data is conducted and the results show that transformer aging costs can be reduced by an order of magnitude by managing adoption rates and strategies. When incentivization costs are included, the optimal HEMS penetration and net benefit are reduced, but a value proposition still exists for targeted HEMS adoption.

In this paper, fast capacitor assignment algorithms capable of finding a decoupling solution scheme with a minimum number of components that meets a predefined target impedance with a semi-arbitrary shape within a few seconds to an hour for a given power distribution network (PDN) are proposed. The proposed algorithms also provide identification of shadowed decap ports in a PDN based on an inductance matrix extraction from the given PDN model. Elimination of those shadowed decap ports with the proposed algorithms enables more effective layouts and cost savings on PCB designs.

In the present research, the application of a proposed, modified, central force optimisation method for multi-objective optimisation of water distribution systems is examined. This new method is based on a central force optimisation algorithm in which the non-dominated sorting plus crowding distance calculator mechanisms produce optimal Pareto solutions in objective functions trade-offs. Minimising pipe-sizing cost and maximising new reliability measures are considered as objective functions. The method is written in Matlab and linked with Epanet water distribution software. Employing the method to solve the Kadu and Khorramshahr water distribution networks shows its capability to produce well-distributed optimal Pareto solutions for cost and reliability. Also, by utilising a fuzzy ranking method, a best compromise solution for two objectives can be extracted from the optimal Pareto set.

For nearly 20 years, the Test Feeder Working Group of the Distribution System Analysis Subcommittee has been developing openly available distribution test feeders for use by researchers. The purpose of these test feeders is to provide models of distribution systems that reflect the wide diversity in design and their various analytic challenges. Because of their utility and accessibility, the test feeders have been used for a wide range of research, some of which has been outside the original scope of intended uses. This paper provides an overview of the existing distribution feeder models and clarifies the specific analytic challenges that they were originally designed to examine. Additionally, this paper will provide guidance on which feeders are best suited for various types of analysis. The purpose of this paper is to provide the original intent of the Working Group and to provide the information necessary so that researchers may make an informed decision on which of the test feeders are most appropriate for their work.

© 2010-2012 IEEE. This paper presents a method to achieve optimal active and reactive power contributions from each energy storage system in an unbalanced distribution network to minimize power loss, while ensuring network current and voltage constraints are satisfied. By modeling loads as either constant current or constant impedance, the ac optimal power flow is transformed into a noniterative convex optimization problem. The application of capacity constraints, voltage constraints, and energy storage constraints in an unbalanced three-phase four-wire system is considered, addressing specific issues pertaining to unbalanced networks such as voltage unbalance and neutral voltage displacement. The proposed method is then used to demonstrate optimized dispatch of energy storage systems in a suitable four-wire unbalanced distribution test network. The contribution of losses in the neutral wire to the total losses is also determined for a test system under a range of operating conditions and various neutral earthing systems, highlighting the importance of considering this in a typical unbalanced distribution network.

Australia has likely the world's highest residential photovoltaic (PV) system penetration. In this paper, the impact of distributed PV on peak demand at different distribution network zone substations (ZSs) is assessed by upscaling 15 min PV generation data from 270 distributed PV systems across Sydney, Australia, and comparing it with load data from 138 ZS serving the Sydney region. Gross load (load had there been no PV) was estimated, allowing the impact of current and higher PV penetrations on the value and time of peak at the different ZSs to be assessed. A probabilistic assessment of the impact of PV on ZSs is conducted, based on the availability of PV during the peak demand periods. To better understand the impact of PV on peak demand, K-means clustering is used to group ZSs based on PV generation during peak periods as the clustering features. Mapping of PV availability across percentage of peak times for all ZSs highlights the interannual variability of peak reductions and the potential impact of short-term load shifting. The impact of different penetration levels of distributed PV on the peak demand of the entire distribution network is also assessed by aggregating the ZS loads.

Distribution expansion planning (DEP) is used to determine the best expansion plan of a distribution system. Considering the uncertainties of loads and of power productions of wind distributed energy resources (DERs) and incorporating AC power flow equations make the DEP problem increasingly challenging. In this context, this paper presents a new adaptive robust distribution expansion planning model to identify the timing of feeder reinforcements in addition to the location, capacity, and installation time of dispatchable and wind DERs. The proposed approach characterizes the uncertain nature of loads and power productions of wind DERs through polyhedral uncertainty sets and the robustness of the solution can be controlled by means of a budget of uncertainty. Since AC power flow equations rather than DC ones are considered, the proposed model is a nonlinear and non-convex min–max–min optimization problem, which cannot be solved directly by commercial optimization packages. Hence, a tri-level decomposition algorithm using both primal and dual cutting planes is introduced to solve the problem. Additionally, to attain a smoother optimization problem, the non-convex AC power flow equations are convexified. The working of the proposed model is illustrated using 33-bus and 123-bus distribution networks.

Renewable distributed generation (DG) is likely to be actively controlled in future distribution networks to mitigate voltage issues resulting from high penetrations. This requires under-standing the corresponding dependencies between voltage magnitudes and DG active/reactive power outputs. One approach to compute these dependencies is to use classical sensitivity methods such as those based on the Jacobian matrix inverse. However, updating the latter involves extensive remote monitoring. This paper presents a novel approach to produce voltage sensitivities applying the Surface Fitting technique on data based solely on the knowledge of network characteristics; making it suitable for decentralized DG control. To assess the benefits, comparisons with classical methods are carried out using the 16-bus UK GDS test network (1-min resolution simulations) considering a decentralized voltage control algorithm that simultaneously caters for the active and reactive power outputs of a single DG plant. The robustness of the proposed approach is also investigated considering changes in network parameters. Finally, the use of coordinated time delays is proposed to cater for multiple DG plants. Comparisons with a centralized optimization demonstrate that the combined use of the proposed voltage sensitivity approach and decentralized control algorithm is an effective and implementable candidate to actively manage renewable DG plants.

The planning of charging facilities (CFs) for electric vehicles (EVs) plays an important role for the extensive applications of EVs. Uncertainties existing in the development of future EV technology should be properly modeled to ensure the robustness of the planning scheme. The uncertainties concerned include EV development types, growth rate of load and traffic flow, and distributions of load and traffic flow in the smart grid. The existing single-stage planning model cannot fully evaluate the risks brought by all kinds of uncertainties. Given this background, the multistage CF planning problem considering uncertainties is studied in this work. First, several typical uncertainties in future smart grid with a high penetration of EVs are considered to generate development scenarios for multistage planning. Then, the well-established data envelopment analysis is utilized to evaluate the planning schemes while the novel EV expected energy not supplied cost is defined to measure the service ability of CFs. The final planning result obtained by the proposed framework will not only have good performance in the current stage but also exhibit robustness for all the considered scenarios in the future stage with respect to uncertainties. The application potential of the designed multistage planning framework is proved by an example with both the distribution network and traffic network included.

Significant financial losses due to voltage sags, short duration interruptions (SDIs), and long duration interruptions (LDIs) have been reported over the past years. The methods proposed in the literature allow us to estimate the annual indices related to process trips, though, as they are confined to voltage sags and LDIs, they do not take into account SDIs. This paper proposes to estimate annual financial losses related to process trip (FLPT) for each customer in the distribution system. The methodology correlates the attempts of reclosers to clear nonpermanent faults along with the concept of process immunity time in order to separately estimate the annual FLPT due to voltage sags, SDIs, and LDIs. This division allows the utility to quantify the severity of each of them and identify geographic areas where mitigation solutions should be deployed to avoid customer complaints and penalties by regulatory agencies.

Due to the unique structure and special characteristics of electric distribution networks, along with the increase in the number and severity of the natural disasters in recent years, presenting a proper framework and procedure for evaluating the resiliency of these systems is more essential. In addition, it is obligatory to model the different capabilities and features of the smart grids components in order to provide a better knowledge about their expected performance in such circumstances. In response to these challenges, this paper addresses the concept of resiliency and its dimensions in distribution networks. A new model based on mixed-integer linear programming is proposed to properly model and evaluate the resiliency of smart distribution systems. In the proposed model, optimal formation of dynamic microgrids (MGs), their service areas, and the optimal management of different technologies such as energy storage (ES) units, demand side management programs and distributed generations (DGs) units are investigated. In addition, employing a two-stage framework based on stochastic programming, the impact of increasing penetration level of the renewable energy resources and their related uncertainties on system resiliency is examined. The efficiency and applicability of the proposed integrated model is verified by performing multiple simulations on the modified 118-bus test system and a real distribution network.

Nowadays, modern industrial processes are controlled by equipment highly sensitive to voltage sags and interruptions. Although the proposed methods in the literature allow utilities to estimate annual equipment trips due to voltage sags and permanent interruptions, they do not assess explicitly momentary interruptions. This paper proposes a probabilistic methodology that includes the attempts of reclosers to clear nonpermanent faults during the estimation of annual voltage sags and momentary interruptions at each busbar. Furthermore, voltage-tolerance ranges for each type of equipment are taken into account to quantify annual equipment trips due to voltage sags and momentary interruptions for each customer in the distribution network. The results allow the utility to identify a geographic area where sets of customers face high equipment trips during the year. The proposed methodology can be used by utilities to prioritize corrective measures to improve the quality of service to those customers most affected by annual equipment trips.

Plug-in Electric Vehicles (PEVs) are active loads as they increase the distribution network’s demand during charging and can have potential impacts on the network. This study discusses the impact of PEV charging on a distribution feeder serving commercial customers and proposes a mitigation strategy to make PEV penetration transparent to the grid. The proposed strategy relies on coordinated control of major loads in demand responsive commercial buildings, ice storage, along with strategically deployed solar photovoltaic (PV). A real world electrical distribution feeder serving a number of commercial buildings is used for analysis purposes. Rather than looking at individual building’s economic benefits, the proposed approach considers overall technical and economic benefits of the whole distribution network, focusing on enhancing distribution-level load factor and reducing feeder losses. Results indicate that by performing load control in selected commercial buildings, along with utilizing capability of existing ice storage units and strategically deployed PV, the proposed approach can absorb 100% PEV penetration, and result in 13.4% decrease in the peak load; 10.9% improvement in the load factor; and 11.6% reduction in feeder losses. Sensitivity analysis shows that both load control and PV are needed to absorb any PEV penetration above 50% level.

Islanding operation in a distribution network connected to Distributed Generations (DGs) has the advantage of being able to continuously supply power to the loads even when disconnected from the grid. However, there are technical issues that need to be solved in order to guarantee a successful islanding operation. The main challenge in the successful islanding operation is to ensure the stability of frequency and voltage of the distribution system. Commonly load shedding schemes are used as a mechanism to stabilize the magnitude of the frequency and the voltage by shedding some of the loads to ensure an adequate balance between generation and loads. This paper reviews recent load shedding schemes focusing on distribution system application. Their respective merits and demerits are presented. Moreover, this paper also highlights the application of Voltage Stability (VS) index for load shedding schemes. A brief overview of the DG with their respective advantages also presented at the beginning of this paper.

This paper presents a reliable protection scheme for high impedance fault (HIF) detection in large and complex electrical distribution networks. The proposed algorithm uses dynamic features extracted by stationary wavelet transform and feeds them to a support vector machine-based decision making system. HIF occurrence is detected according to the normalized changes of the features extracted from three post-disturbance data windows. To provide more security, the output of the main fault classifier is compared with the outputs of three other classifiers in a voting system for final decision making. The results of simulations of a real distribution system demonstrate that the proposed scheme is able to detect a wide range of arcing faults, from a few amperes to hundreds of amperes, with high level of security against non-HIF phenomena.

Adequately accounting for interactions between Low Carbon Technologies (LCTs) at the building level and the overarching energy system means capturing the granularity associated with decentralised heat and power supply in residential buildings. This paper combines dwelling/household archetypes (DHAs) combined with a mixed integer linear program to generate optimal (minimum cost) technology configurations and operation schedules for individual dwellings. These DHAs are scaled up to three socioeconomically differentiated neighbourhood clusters at the Output Area level in the UK. A synthetic distribution network generation and simulation assesses the required network upgrade costs for these clusters with different LCT penetration scenarios. Whilst the application here is to the United Kingdom (UK) setting, the method is largely based on freely available data and is therefore highly transferable to other contexts. The results show significant differences between the upgrade costs of the three analysed network types, and especially the semi-rural cluster has much higher costs. The employment of heat pumps together with photovoltaics (PV) has strong synergy effects, which can considerably reduce the network upgrade and carbon abatement costs if deployed in parallel. The determined CO 2 -abatement costs also suggest that decarbonisation measures with these two technologies should focus on semi-urban neighbourhoods due to the lower cost in comparison to the semi-rural case. This shows that such a socioeconomically differentiated approach to distribution network modelling can provide useful energy policy insights.

Water Distribution Networks (WDNs) are vulnerable to accidental or deliberate contamination. Such contamination can be detected and identified by deploying a network of sensors. If the sensor network detects the presence of a contaminant, it is also very important to take corrective response actions to minimize the effects of contamination on the population being served. One possible mitigation option is to prevent the contaminated water from reaching any customer, by shutting down the distribution network using shut-off valves placed in the WDN. The design problem considered in this work is to determine pipes where the shut-off valves can be optimally located such that it is possible to prevent the contaminated water from reaching any demand point, regardless of the source node from where the contamination has originated. We refer to this problem as the actuator network design problem. We map the problem of actuator design into a graph partitioning problem and the minimal set of actuators are identified for ensuring the total shutdown of the network.

Tertiary packaging is necessary for transportation in any production and distribution network because of the benefits in enhancing the logistics efficiency. However, in the meantime, it produces a lot of packaging waste every day. In fact, some tertiary packaging after transportation may still be in good condition and can be collected back for reuse. However, this has not been widely studied in the existing literature. The purpose of this research is to fulfill this research gap. Accordingly, the contribution of this paper is to propose a new optimization methodology, named modified Genetic Algorithm with Crossing Date heuristic, to maximize the collection of used tertiary packaging for reuse, meanwhile minimize the total operating cost by taking the advantages of simultaneous optimization of a multi-day planning. From the numerical experiments, it is found that the optimization ability of proposed new optimization methodology outperform the traditional genetic algorithm by a maximum of about 10%. In addition, the total operating cost is found can be reduced by using the proposed multi-day planning approach.

Ahybrid simulation-optimization approach is developed in this study foroptimally designing the booster chlorination systems in water distributionnetworks. In the developed approach, chlorine residuals in the demand locationsare determined by using the response matrix (RM) approach. The generated RM isthen integrated to an optimization model where a hybrid HS–Solver optimization approachis used. HS-Solver is a recently proposed hybrid approach which integrates the harmonysearch (HS) algorithm and a spreadsheet Solver as the global and localoptimizers, respectively. The objective of the HS-Solver in the developedapproach is for optimally designing the booster stations by maintaining thechlorine residuals within desired limits. The applicability of the developedapproach is tested on a real water distribution network. Identified resultsindicate that the developed HS-Solver based solution approach determined similar or better results thanthose obtained by using the different solution approaches in literature., Bu çalışmada, su dağıtımşebekelerindeki ek klorlama istasyonlarının optimum tasarımı amacıyla birhibrit simülasyon-optimizasyon yaklaşımı geliştirilmiştir. Geliştirilenyaklaşımda, talep noktalarındaki bakiye klor konsantrasyonları tepki matrisiyaklaşımı ile belirlenmiştir. Oluşturulan tepki matrisi ardından hibritHS-Solver optimizasyon yaklaşımının kullanıldığı bir optimizasyon modelineentegre edilmiştir. HS-Solver, armoni araştırması ile elektronik tablolamaprogramlarında kullanılan Solver eklentisinin sırasıyla global ve lokaloptimizasyon aracı olarak kullanıldığı yeni önerilmiş bir optimizasyon yaklaşımıdır.Geliştirilen yaklaşımda HS-Solver’ın amacı bakiye klor konsantrasyonlarını arzuedilen limitlerde tutacak şekilde ek klorlama istasyon sisteminin optimumtasarımını yapmaktır. Geliştirilen yaklaşımın uygulanabilirliği gerçek bir sudağıtım şebekesi üzerinde test edilmiştir. Elde edilen sonuçlar, geliştirilenHS-Solver tabanlı çözüm yaklaşımı ile literatürde verilenlerle uyumlu veya dahaiyi sonuçlar elde edilebildiğini göstermiştir.

In this paper, the operation scheduling of future distribution network is discussed under assumption of multi-microgrids. The economic operation scheduling of distribution network operator in the presence of autonomous microgrids is formulated as a game problem. Due to participation of multiple players with different objective functions, the multi follower bi-level programming is intended in the energy management scheme. From the distribution network operator's perspective, the decision-making strategy seeks to minimize the operation costs of distribution network operator. Distribution network operator interconnecting with upstream grid and interaction with microgrids, schedules distributed energy resources and loads in economical matter to operate in optimal operation point. On the other hand, microgrid owners fed electrical loads interacting with the other microgrids and distribution network operator implementing demand response program during the scheduling horizon to acquire maximum profit. Therefore, the key focus of this approach is decision-making of distribution network operator which will be affected, not only by the reactions of microgrids, but also by the exchanging power between the microgrids. The paper discusses the theoretical background, architecture and algorithms of the proposed multi follower bi-level programming, and demonstrates the performance of distribution network operator and microgrids by means of simulation on the radial distribution test system.

Improved understanding of the development with time of pitting and corrosion of the external surfaces of buried cast iron water pipes is crucial for the management of water supply distribution networks. The present study reports observations of surface topography of cast iron pipes exposed between 34 and 129 years in clay soils. Pit depths, surface areas and widths associated with deeper pits are reported, including as functions of exposure period. Pitting appears to progress in a step-wise manner as also earlier reported for the corrosion of steels. While there is a relation between pit depth and lateral size of pits through the amalgamation of pits to form plateaus into which new pits tend to form, the predominant progression of material loss through corrosion and pitting is into the metal rather than laterally. The practical implications of these observations are discussed.

Recent research has presented a load scaling based real time state estimation (SE) approach for radial and multiphase distribution networks; the approach makes use of successive weighted least squares estimation and power flow to adjust forecasted load values so that they conform with the available real time measurements. This paper extends the load scaling based SE approach along two directions, while maintaining performance that is commensurate with real time computing requirements. First, the approach is extended to allow for meshes that are practically available in some distribution systems; this is achieved by embedding the power flow equations of the nodes that are part of the loops within the load scaling formulation. Second, a sensitivity-based technique is introduced to handle isolated line-to-ground voltage magnitude measurements in radial feeders; this technique is compatible with load scaling and is timely as many utilities have increased the monitoring of voltage measurements at pilot nodes to guard against voltage problems that are associated with distributed generation. The efficiency of the proposed estimator is demonstrated by comparison with the three-phase voltage based normal equations approach that handles both voltage magnitudes and meshes.

The technical planning process, performed by distribution network operators (DNOs) in order to determine the necessary reinforcements in the electrical distribution networks, is strongly affected by the demand forecasting methodologies adopted. Such methodologies aim to correlate consumers' behavior/environmental variables with the power necessary to supply the consumers. In this context, the level of connected distributed generation units (DGs) has been incorporated into the demand forecasting methodologies. Brazilian electricity policies allow DNOs to consider the DGs intrinsic limitations (for example, seasonality and reliability aspects) in their demand forecasting methodologies. However, the regulatory laws do not allow DNOs to consider the external aspects involved in distributed generation process. Therefore, this paper proposes an improvement in the technical planning process guidelines, in order to consider the external aspects mentioned above.

Municipalities in Canada have noted that 59% of their water systems need repair, and the condition of 43% of those systems is apparently intolerable. Hence, large volumes of rehabilitation projects are necessary to improve the performance of Canadian water systems. A reliability (R) and criticality index (CI) are crucial for prioritizing rehabilitation activities and distribute budgets efficiently. “R”is a function of failure rate, while“CI”is a function of economic, operational, social, and environmental factors. The research presented in this paper aimed to develop a performance index (PI) that considered the combination of “R” and “CI” for water networks. Sound techniques were utilized to generate the PImathematical model, such as reliability theory, simple multi-attribute rating technique (SMART), and Analytical Hierarchy Process (AHP). Data on water networks were collected from the city of Hamilton, Ontario, Canada. Four sub-networks were selected from the entire network to represent four types of land uses; undeveloped, residential, park, and commercial/industrial. The results showed that the PI value was 0.72, 0.93, 0.87, and 0.76 for these types of land uses, respectively. The developed models and tools are assumed to be beneficial for municipal engineers and managers as well as academics.

Today's electricity paradigm requires that the notion of active distribution systems be introduced at both undergraduate and graduate curricula. This involves not only the customary theoretical foundations but also a suitable power engineering laboratory, where flexible enough and affordable resources allow students and researchers to carry out hands-on experiments reinforcing the concepts explained in the classroom. This paper describes the smart grid laboratory of the Power Engineering Group at the University of Seville, composed of a scaled-down distribution system, along with the required control and monitoring equipment, designed to help its users easily grasp the major influence that distributed generation and storage devices exert in the operation of medium-voltage distribution systems.