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The quality of electricity is one of the most discussed issues in the regulatory context, structured by guidelines that allow the assessment of efficiency in electricity supply. Regarding electricity distribution systems, it is essential to highlight the aspects associated with the definition of continuity indicators to measure the service provided by the utilities. The parameters used to calculate the indicators are set by specific agencies in each country based on studies and their characteristics. With the growth in demand for electricity, debates associated with reducing greenhouse gas emissions in the atmosphere, and the increase in Distributed Energy Resources (DERs) connected to the grid, a new trend related to the energy supply is verified. Given these new scenarios, this paper presents a literature review in the regulatory field of existing distribution systems in South American countries. The research proposes to analyze, compare, and expose the current models to evaluate their methods and indicators, including a complete case study in Brazil. This paper seeks to illustrate and point out perspectives, challenges, and future perspectives through the collected and analyzed data. [ABSTRACT FROM AUTHOR]

In the present work the problem of Optimal Placement of remote controlled switches, through the replacement of installed manual switches, in Electric Power Distribution Systems with radial configuration is approached, considering economic, technical, operational and social aspects. The approach used for the identification of strategic points is based on the implementation of meta-heuristic algorithms for optimization with multiple objectives. For the evaluation of each solution, an evaluating function based on the Monte Carlo method is implemented, which estimates the defined indices through the simulation of failures in the network, whose probabilities are obtained using the Reliability Block Diagram method. Three different multi-objective algorithms were implemented and their results compared using the hypervolume metric, having the Generalized Differential Evolution 3 algorithm the best performance. [ABSTRACT FROM AUTHOR]

Distribution network is an essential part of electric power system, which however has higher power losses than transmission system. Distribution losses directly affect the operational cost of the system. Therefore, power loss reduction in distribution network is very important for distribution system users and connected customers. One of the commonly used ways for reducing losses is distribution system reconfiguration (DSR). In this process, configuration of distribution network changes by opening and closing sectional and tie switches in order to achieve the lowest level of power losses, while the network has to maintain its radial configuration and nodal voltage limits, and supply all connected loads. The DSR aiming loss reduction is a complex mixed-integer optimization problem with a quadratic term of power losses in the objective function and a set of linear and non-linear constraints. Accordingly, distribution network researchers have dedicated their efforts to developing efficient models and methodologies in order to find optimal solutions for loss reduction via DSR. In this paper, an efficient mathematical model for loss minimization in distribution network reconfiguration considering the system voltage profile is presented. The model can be solved by commercially available solvers. In the paper, the proposed model is applied to several test systems and real distribution networks showing its high efficiency and effectiveness for distribution systems reconfiguration.

The quality of electricity is one of the most discussed issues in the regulatory context, structured by guidelines that allow the assessment of efficiency in electricity supply. Regarding electricity distribution systems, it is essential to highlight the aspects associated with the definition of continuity indicators to measure the service provided by the utilities. The parameters used to calculate the indicators are set by specific agencies in each country based on studies and their characteristics. With the growth in demand for electricity, debates associated with reducing greenhouse gas emissions in the atmosphere, and the increase in Distributed Energy Resources (DERs) connected to the grid, a new trend related to the energy supply is verified. Given these new scenarios, this paper presents a literature review in the regulatory field of existing distribution systems in South American countries. The research proposes to analyze, compare, and expose the current models to evaluate their methods and indicators, including a complete case study in Brazil. This paper seeks to illustrate and point out perspectives, challenges, and future perspectives through the collected and analyzed data.

The increasing penetration of photovoltaic (PV) generators installed in low voltage networks has raised concerns about the potential impacts of these devices in overcurrent protection. As these generators are installed in a wide-scale and widely dispersed fashion in low voltage networks, they may require new study methods by utility engineers, which traditionally deal with few large synchronous generators connected at medium voltage level. To clarify whether new study methods are in fact needed or not, this paper provides a detailed analysis of the potential impacts of PV generators on the network overcurrent protection. Coordination and selectivity among circuit breaker, recloser, lateral and service transformer fuses are assessed by considering high levels of PV penetration. The full protection scheme, installed in substation, main feeder, feeder lateral, and service transformer is evaluated. Results reveal that, even under high PV penetration scenarios, the contribution of PV generators to short-circuit currents is not large enough to affect the protection scheme of the studied system. [ABSTRACT FROM AUTHOR]

The popularity of electric springs (ESs) has been grown in the last years mainly due to the boost in the growth of smart grids (SGs) and micro‐grids (μGs), as well as the high penetration of renewable energy sources. In general, ESs have a hardware structure similar to other compensator devices such as distributed flexible AC transmission systems or active filters. ESs offer the exchange of active and reactive powers with the electrical grid and the demand‐side load management. Their ability to simultaneously perform multiple tasks without the need of modifying their hardware structure classifies them as smart loads, distinguishing them from other types of compensators such as active filters, hybrid filters, dynamic voltage restorers, and distribution static VAR compensators, among others. In this work, an exhaustive review of ESs is carried out to cover their three main research trends, i.e. hardware structure evolution, different types of controllers, and applications in electric power distribution systems, SGs, and μGs. Moreover, their main advantages, disadvantages, and contributions in the power quality improvement are discussed. This review clarifies future research trends that have to be explored to advance the subject. [ABSTRACT FROM AUTHOR]

The integration of renewable energy (RE)‐based distributed generation (DG) with electric power distribution systems (DSs) in association with smart grid technology has numerous benefits, however, due to their intermittent nature, the utilisation of RE‐based DG may pose threats to the proper operation of conventional overcurrent (OC) protection schemes. The resulting threats, malfunctions, and non‐selective actions could occur by relays within the DS, and the development of efficient protection schemes is necessary. The objective of this study is to propose and simulate an adaptive OC protection scheme in DSs in the presence of doubly‐fed induction generator (DFIG) wind turbines based on wind speed forecast data with considerations for wind speed forecast uncertainty and a low‐voltage ride‐through requirement for wind turbines. In each time interval and possible operating mode, the output power of DFIG‐based wind turbines and relay setting parameters are determined offline. The results show that the proposed protection scheme prevents malfunctions and non‐selective operations of relays, and also provides faster fault isolations, as compared to the conventional OC protection scheme. [ABSTRACT FROM AUTHOR]

Accurate fault location in an electric power distribution system (EPDS) is important in maintaining system reliability. Diverse methods have been proposed in the past. These methods whither require measurements at each load point or use single-step loads compensation, which is hardly available in practical uses. In this paper, a simple technique to bypass the load problems is proposed. The method requires calculating an optimal load distribution using the total load seen from the substation (The rated power of distribution transformers) and the network topology. The optimal load distribution is used as a fictive distribution to replace the real unknown one in fault location (FL) algorithms. The effectiveness of the proposed technique is demonstrated using a mathematical formulation first, and next, by several simulations with a classic iterative fault location algorithm. The test results are obtained from the numerical simulation using the data of a distribution line recognized in the literature.

High penetration levels of electric vehicles (EVs) in distribution networks will create significant operational challenges to distribution system operators and demand robust methods to optimize the charging problem. This work addresses the problem of controlling the charging of electric vehicles in low voltage distribution systems using an optimization framework formulated as a scheduling problem. A computationally efficient procedure with a detailed modeling of the network is sought. The objective is to obtain a charging schedule for all the EVs connected to the network satisfying a set of network operational constraints. The approach uses a complete AC three-phase modeling of the network and deploys a time-series power flow coupled with a greedy heuristic to obtain a smart charging procedure over a fixed planning period considering the variable behavior of loads and EV connection patterns. Distribution network constraints consider phase unbalance, transformer and line limitations, and node voltage limits. The approach is tested on an IEEE low voltage distribution test feeder. [ABSTRACT FROM AUTHOR]

In the electrical power systems, load is one of the most difficult elements to be represented by an adequate mathematical model due to its complex composition and dynamic and non-deterministic behavior. Nowadays, static and dynamic load models have been developed for several studies such as voltage and transient stability, among others. However, on the issue of power quality, dynamic load models have not been taken into account in fault location. This paper presents a fault location technique based on sequence components, which considers static load models of constant impedance, constant current and constant power. Additionally, an exponential recovery dynamic load model, which is included in both the fault locator and the test system, is considered. This last model is included in order to consider the dynamic nature of the load and the performance of the fault locators under this situation. To demonstrate the adequate performance of the fault locator, tests on the IEEE 34 nodes test feeder are presented. According to the results, when the dynamic load model is considered in both the locator and the power system, performance is in an acceptable range.

This paper presents a time domain technique used to solve the fault location problem for power distribution systems considering the dynamic load model. The proposed technique uses the voltage and current signals during the transient and steady states, measured at the main distribution substation, through time and phasor domain iterative analysis. The load dynamics is considered by its estimation at each sampling step. The accuracy of the proposed technique is determined by using a fault database obtained from the IEEE 34 bus distribution system. The fault locator is tested considering uncertainties associated with the fault type, fault resistance, voltage magnitude and angle unbalance at the source, load magnitude, power factor and the power system frequency. The obtained results show that the fault locator accuracy depends on the time of data acquisition, and the obtained performance is adequate for utility applications. [ABSTRACT FROM AUTHOR]

The increasing of distributed generators and high demand of customer service quality of recent years keep challenging the design and operation of electric power distribution systems. The future smart distribution grid is envisioned to be a large complex cyber‐physical distribution system (CPDS), where physical grid components are monitored and controlled based on the interactions on the cyber space. As sensors and controllers, smart feeder remote terminal units (FRTUs) transfer necessary data to the control centre for situational awareness, and receive orders from the control centre for dynamic controlling. This study introduces an analytical FRTU deployment approach for the reliability improvement of integrated CPDSs. The FRTU deployment problem is modelled as a mixed‐integer non‐linear programming problem, which aims to minimise the total cost with the reliability index of average service available index as the constraint. Two kinds of distribution feeders (overhead and underground) are considered. The total cost includes the life cycle cost of FRTUs in addition to customer interruption cost. The proposed model can be solved by large‐scale commercial solvers in an efficient manner. Test results of the RBTS‐BUS4 distribution system and a China Southern Power Grid 62‐bus distribution system validate the accuracy and effectiveness of the approach. Comparison with the genetic algorithm also shows its great efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a solution strategy for planning and project distribution system problems. This model applies concepts of Tabu Search (TS) metaheuristic to provide a complete solution for the problem, from distribution substations to individual consumers, making it able to be implemented by distribution companies. A 50-bus network was used to evaluate this method that obtained feasible and good solutions for planning and project distribution systems. [ABSTRACT FROM PUBLISHER]

Accurate Fault location in an Electric Power Distribution System (EPDS) is important in maintaining system reliability. Several methods have been proposed in the past. However, the performances of these methods either show to be inefficient or are a function of the fault type (Fault Classification), because they require the use of an appropriate algorithm for each fault type. In contrast to traditional approaches, an accurate impedance-based Fault Location (FL) method is presented in this paper. It is based on the voltage-sag calculation between two measurement points chosen carefully from the available strategic measurement points of the line, network topology and current measurements at substation. The effectiveness and the accuracy of the proposed technique are demonstrated for different fault types using a radial power flow system. The test results are achieved from the numerical simulation using the data of a distribution line recognized in the literature. [ABSTRACT FROM AUTHOR]

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• Practical method to determine whether shunt/series ESS can mitigate voltage sags. • Auxiliary chart obtained easily and analytically. • The method obtains Energy Storage System capacity required to mitigate voltage sags. • The method obtains the optimum power factor for operation of Energy Storage System. Energy storage systems (ESS) have attracted significant interest and investments. Despite this interest, industry and utility engineers have not widely considered this technology as a potential solution to improve the power quality supplied for critical loads. This is in part because of the high cost and in part because of the high complexity to assess this type of solution. This paper, therefore, proposes a practical approach to determine whether shunt/series ESS can mitigate voltage sags assuming the availability of system information, as short-circuit impedance and historical voltage sags, and load information. This is done by analyzing a chart obtained analytically, which can be easily constructed based on simple information from the system and load, without resorting to computer simulations. By inspecting this chart, engineers can quickly determine not only the ESS capacity required to mitigate specific sags, but also which is the optimum power factor for operation. Sensitivity studies are provided to reveal key factors affecting ESS capability to mitigate voltage sags and to validate the proposed approach. Results outline that the requirements of shunt ESS depend on the system short-circuit level and X / R ratio, whereas requirements of series ESS depend on the load demand and power factor. [ABSTRACT FROM AUTHOR]

In this paper, a technique based on nondominated sorting genetic algorithm-II (NSGA-II) is presented for solving the service restoration problem in an electric power distribution system. Due to the presence of various conflicting objective functions and constraints, the service restoration task is a multiobjective, multiconstraint optimization problem. In contrast to the conventional genetic-algorithm (GA)-based approach, this approach does not require weighting factors for the conversion of such a multiobjective optimization problem into an equivalent single objective function optimization problem. In this work, various practical distribution system operation issues, such as the presence of priority customers, presence of remotely controlled, as well as manually controlled switches, etc. have also been considered. Based on the simulation results on four different distribution systems, the performance of the NSGA-II-based scheme has been found to be significantly better than that of a conventional GA-based method. Besides, to reduce the software runtime of the NSGA-II algorithm, a faster version of NSGA-II has also been implemented. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a New Hybrid Multi-Objective Quick Service restoration (QSR) technique for Electrical Power Distribution Systems (EPDS). The main features of this new technique includes the development New Network Connectivity Method, objective function formulation with the consideration of various constraints in addition to the Priority Based Load Constraints and the incorporation of Service Restoration Time Estimation which helps the Electrical Power Distribution Engineers (EPDE) to restore the supply in minimum time. In order to satisfy various operational constraints while restoring the power supply to the consumer localities, the capacity of Transformer/Feeders in the post fault distribution network creates a serious problem to the EPDE and Distribution System Substation Operators (DSSO). Hence, the Electric Power Service Restoration Problem (EPSRP) becomes a nonlinear, combinatorial, non-differential and multi-objective optimization problem with several constraints. The solution to this multi-objective optimization problem has been obtained using a New Hybrid Method. A Computer program has been developed to solve this EPSRP. The validity of this new approach bas been tested on the various EPDS viz., 12-Bus, 15-Bus, 16-Bus, 26-Bus, 29-Bus, 33-Bus, 69-Bus, 79-Bus and 133-Bus systems. The fast and effective convergence of this approach helps to find the Optimal Operating Condition for the QSR of EPDS. The results reveal that it is a highly suitable technique for use in Service Restoration Procedures of Distribution Automation Systems (DAS). [Copyright &y& Elsevier]