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Energy storage systems (ESSs) can improve energy management in distribution grids, especially with the increasing penetration of home energy management systems (HEMSs) that schedule household appliances and render them as smart loads. A large number of uncoordinated HEMSs can result in significant changes to the aggregated load profile of the distribution system. This paper proposes a framework and mathematical model for integrating ESS in the distribution grid to minimize the operation cost of the local distribution company (LDC) and alleviate the impact of uncoordinated HEMS operation on the distribution grid. A novel neural network (NN) based state of health (SoH) estimator for a lithium-ion (Li-ion) battery based ESS is proposed, which is incorporated within the LDC's planning problem. The results show that the proposed estimation model is an accurate estimation of the SoH of the ESS. The LDC's planning decisions are also compared, considering SoH of the ESS vis-á-vis linear degradation and no-degradation models. [ABSTRACT FROM AUTHOR]

One of the main advantages of smart grids is the presence of advanced communication technologies that facilitate grid operators and local distribution companies (LDCs) to communicate directly with customers. While at one end, the end-user customers seek to optimize their energy consumption by deploying home energy management systems (HEMSs), the LDCs on the other hand, seek to improve the grid operational efficiency and reduce losses. In this paper, a two-stage optimization framework is developed wherein multiple HEMS simultaneously optimize their respective energy consumption patterns, and determines their flexibility provision, which is communicated to the LDC. The LDC aggregates the controllable demand profile and the flexibilities of each HEMS to optimize its operational performance and hence the peak reduction signals which are sent to the HEMS. Studies are carried out considering a 33-bus distribution system coordinating with 1295 houses connected at different buses, and with varying customer preferences and objectives to demonstrate the applicability of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper describes the development of a freeware smart residential load simulator to facilitate the study of residential energy management systems in smart grids. The proposed tool is based on MATLAB-Simulink-GUIDE toolboxes and provides a complete set of user-friendly graphical interfaces to properly model and study smart thermostats, air conditioners, furnaces, water heaters, stoves, dishwashers, cloth washers, dryers, lights, pool pumps, and refrigerators, whose models are validated with actual measurements. Wind and solar power generation as well as battery sources are also modeled, and the impact of different variables, such as ambient temperature and household activity levels, which considerably contribute to energy consumption, are considered. The proposed simulator allows modeling of appliances to obtain their power demand profiles, thus helping to determine their contribution to peak demand, and allowing the calculation of their individual and total energy consumption and costs. In addition, the value and impact of generated power by residential sources can be determined for a 24-h horizon. This freeware platform is a useful tool for researchers and educators to validate and demonstrate models for energy management and optimization, and can also be used by residential customers to model and understand energy consumption profiles in households. Some simulation results are presented to demonstrate the performance and application of the proposed simulator. [ABSTRACT FROM AUTHOR]

Load characteristics play an important role in distribution systems, which are traditionally designed to supply peak load; hence, decreasing this peak can considerably reduce overall grid costs. Basic components of smart grids such as smart meters allow two-way communication between the utilities and customers; in this context, controllable smart loads are being introduced, which allow developing and implementing energy management systems for customers and distribution feeders. Therefore, this paper studies the impact of existing smart loads, in particular Peaksaver PLUS (PS+) loads in ON, Canada, to reduce summer peak loads for distribution feeders. A neural network model of controllable loads is developed and integrated into an unbalanced distribution optimal power flow (DOPF) model to optimally control tap changers and switched capacitors, as well as sent signals to programmable thermostats of air conditioners in residential buildings, in particular those associated with the PS+ program. The developed integrated DOPF is tested and validated using a practical system, demonstrating the benefits of using existing controllable loads to optimally operate distribution feeders. [ABSTRACT FROM AUTHOR]

This paper presents a queuing analysis-based method for modeling the 24-h charging load profile of a plug-in electric vehicle (PEV) charging station. The queuing model considers the arrival of PEVs as a non-homogeneous Poisson process with different arrival rates over the day. The first PEV charging load profile assumes customer convenience as the factor that influences the hourly arrival rate of vehicles at the station, while the second profile is developed assuming that customers would respond to PEV charging prices and arrival rates are accordingly affected. One of the main contributions of this paper is to model the PEV service time considering different factors such as the state-of-charge of the vehicle battery, as well as the effect of the battery charging behavior. The impact of PEV load models on distribution systems is studied for a deterministic case, and the impact of uncertainties is examined and compared using the stochastic optimal power flow and the model predictive control approaches. [ABSTRACT FROM PUBLISHER]

This paper presents a generic and comprehensive distribution optimal power flow (DOPF) model that can be used by local distribution companies (LDCs) to integrate their distribution system feeders into a Smart Grid. The proposed three-phase DOPF framework incorporates detailed modeling of distribution system components and considers various operating objectives. Phase specific and voltage dependent modeling of customer loads in the three-phase DOPF model allows LDC operators to determine realistic operating strategies that can improve the overall feeder efficiency. The proposed distribution system operation objective is based on the minimization of the energy drawn from the substation while seeking to minimize the number of switching operations of load tap changers and capacitors. A novel method for solving the three-phase DOPF model by transforming the mixed-integer nonlinear programming problem to a nonlinear programming problem is proposed which reduces the computational burden and facilitates its practical implementation and application. Two practical case studies, including a real distribution feeder test case, are presented to demonstrate the features of the proposed methodology. The results illustrate the benefits of the proposed DOPF in terms of reducing energy losses while limiting the number of switching operations. [ABSTRACT FROM AUTHOR]