This paper proposes a new multistage AC model for transmission expansion planning that finds an optimal combination of transmission lines, fault current‐limiting high‐temperature superconducting ...cables, and multiple distributed generations (DGs). On this basis, the proposed model, from a new perspective, allows for simultaneous improvement of the short‐circuit level and grid‐scale flexibility (GFLX) under both normal and fault conditions. The objective function to be minimized includes not only the net present worth of the total investment and operation costs but also the congestion‐induced GFLX degradation measure. This model also takes the AC power balance and flow relationships, equipment capacity limits, nodal voltage bounds, DG penetration level limit, as well as discrete logical and financial restrictions together into account with the short‐circuit level constraint. To overcome the complexity of solving the resultant non‐convex mixed‐integer non‐linear optimization problem, a multi‐objective integer‐coded melody search algorithm is employed, followed by a fuzzy satisfying decision‐making mechanism to obtain the final optimal solution. The exhaustive case studies conducted on the IEEE 24‐ and 118‐bus test systems verify the efficacy of the newly developed model in terms of cost‐effectiveness, flexibility, and short‐circuit level suppression when facing different normal and fault conditions.
In this paper, the authors propose a new multistage AC model for transmission expansion planning (TEP) that finds an optimal combination of transmission lines, fault current‐limiting high‐temperature superconducting (FCL‐HTS) cables, and multiple distributed generations (DGs).
In this paper, a new reliability‐based risk‐involved model is presented for multi‐period macrogrid expansion planning (MAGEP) by amalgamating the notion of community microgrids (CoMigs) within a ...market environment. The main targets of the proposed model are not only to develop a holistic framework for the MAGEP problem, but also to scrutinize the impacts of the macrogrid‐connected multi‐CoMigs on power supply reliability enhancement. To that end, the mathematical formulation of the proposed model falls into a nonconvex mixed‐integer nonlinear three‐level optimization problem. The lower‐level outlines a security‐constrained bid‐based‐pool electricity market aimed at providing an efficient platform for different CoMigs and market participants—generation companies (GenCos) and distribution companies (DisCos)—to freely trade electrical power across the macrogrid. The intermediate‐level represents an interactive decentralized multi‐period two‐stage microgrid expansion planning (MIGEP) problem in which optimal expansion plans of the CoMigs obtained in the first stage will be examined against the reliability restrictions in the second stage. The upper‐level, however, addresses a centralized multi‐period techno‐economic MAGEP problem, while handling the risks of planning arising from severe uncertainties in forecasted price, demand, and power generation of the CoMigs through a potent envelope‐bound information‐gap decision theory (IGDT). Due to its proper tackling of the non‐convex mixed‐integer nonlinear multi‐level optimization problems, the symphony orchestra search algorithm (SOSA) is widely employed for solving the proposed model. Effectiveness and capability of the newly developed model are numerically analyzed and verified using its implementation on the IEEE 30‐bus and IEEE 118‐bus test systems.
To develop a reliability‐based three‐level model for the centralized multi‐period techno‐economic MAGEP, considering the interactive decentralized multi‐period two‐stage MIGEP.
To model impacts of the macrogrid‐connected multi‐CoMigs on power supply reliability enhancement.
To provide a risk‐involved strategy to handle severe uncertainties of price, demand, and power generation of the CoMigs through a potent envelope‐bound IGDT.
In this paper, a new flexible load-reliant cost-driven framework is proposed for peer-to-peer decentralized energy trading of an industrial town in which demand response mechanism is modeled for all ...active energy consumers (hereinafter referred to as prosumers). In this industrial town, the prosumers employ multiple photovoltaic panels accompanied by battery and hydrogen energy storage systems (B&HESSs) to deliver the required energy to their own loads and sell the surplus energy to other neighboring prosumers. The objective function to be minimized includes: (i) cost of energy trading within the industrial town; (ii) cost of energy trading between the industrial town and neighboring microgrids; and, (iii) cost of energy trading with the upstream grid. The framework also considers power balance constraint for prosumers and microgrids, feeder capacity limits, allowable maximum capacity of energy trading among prosumers, admissible maximum capacity of energy trading among prosumers and microgrids, voltage bounds for prosumers and microgrids, charging and discharging restrictions of the B&HESSs, flexible load constraint, as well as logical constraints. The resulting non-convex mixed-binary linear optimization problem is solved using a linear programming solver. Case study using the IEEE 33-node distribution test system is presented here in order to illustrate the effectiveness of the newly developed framework. According to simulation results, several conclusions can be briefly drawn: (i) applying the B&HESSs brought about a decrease of 12.33% in the total cost of energy trading between the industrial town-owned prosumers and upstream grid; (ii) exerting the B&HESSs is accompanied by a decrease of 44.33% in the total cost of energy trading among the industrial town-owned prosumers; (iii) the utilization of the B&HESSs is associated with a decrement of 77.15% in the total cost of energy trading between the industrial town and neighboring microgrids; (iv) considering voltage security limits increased the willingness of the industrial town-owned prosumers to participate in demand response mechanism up to 27.53%.
•To design a large-scale industrial town incorporating the PV panels, BESSs and HESSs.•To improve both power sharing among prosumers and peak load of the upstream PDG.•To propose the multilateral interdependence among prosumers, MGs and upstream PDG.•To formulate a flexible load-reliant cost-driven framework for the P2P energy trading.
Popularization of renewable energy sources (RESs), driven by the goal of carbon footprint mitigation in urban areas, invites unprecedented uncertainties into power distribution networks (PDNs). The ...uncertainties stemming from intrinsic intermittency of the RESs force network planners to meet flexibility requirements. For handling this challenge, multiple energy storage systems have recently emerged as a pivotal component across the PDNs. In this sense, the authors of this current study present here a new urban-load density-dependent framework for multi-period distribution expansion planning (DEP) considering hybrid hydrogen/battery/wind/solar energy systems for both flexibility enhancement and transition toward low-carbon PDNs. The proposed framework, from a new perspective, aims to divide the PDNs into multiple zones, according to load density of different urban areas under two simultaneous incommensurable objective functions: (i) minimization of investment and operation and maintenance costs; and, (ii) maximization of the supply-demand-related flexibility (SDF) improvement metric minus network-related flexibility (NTF) degradation metric. As the resultant optimization problem formulation has a challenging non-convex mixed-integer nonlinear structure, a fuzzy-based symphony orchestra search algorithm (F-SOSA) was employed to determine the final optimal solution. The effectiveness of the newly developed framework was verified through simulation results on standard 54-node and realistic 95-node distribution test networks. The results illustrate that the integration of hydrogen/battery energy systems brought about an increase of 9.52% and a decrease of 14.96% for the SDF and NTF, respectively, in comparison to their absence. One can further stat that applying these multiple energy systems is associated with a reduction of 20.64% of the total investment cost.
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•To divide the PDNs into multiple zones according to load density of different urban areas.•To propose the SDF improvement metric together with NTF degradation metric.•To develop a multi-objective model to ensure cost-effectiveness and flexibility requirements.•To explore the impacts of the HESSs, BESSs, WTs and PVs on flexibility enhancement and carbon neutralization purposes.
•To present a resilient four-level framework for the centralized cost-effective multistage DNRP considering decentralized double-layer multistage MGRP.•To model different peak ground accelerations of ...moderate-to-strong earthquakes based on critical seismic parameters.•To provide a non-convex mixed-integer nonlinear formulation for jointly allocating substations, feeders, renewable DERs and ESSs.•To assess seismic vulnerability of substations, feeders and DERs according to their respective fragility curves.
In this paper, a new resilient framework is presented for distribution network reinforcement planning (DNRP) with the consideration of renewable-based multi-microgrids (RMGs) to mitigate seismic risks. For this aim, the proposed framework is formulated as a non-convex mixed-integer nonlinear four-level optimization problem. The first level outlines a short-term corrective measures problem to remedy seismic risks using feeder reconfiguration and distributed energy resources rescheduling. The second level represents an earthquake-related catastrophic failures problem in which peak ground acceleration and distribution component vulnerability are modeled through attenuation functions and fragility curves, respectively. The third and fourth levels, however, describe coordination of a decentralized double-layer multistage microgrid reinforcement planning (MGRP) problem and a centralized cost-effective multistage DNRP problem to characterize seismic-resilient optimal reinforcement plans. Due to its desirable handling of multi-level optimization problems having a non-convex mixed-integer nonlinear nature, the multi-computational-step, multi-dimensional, multiple-homogeneous improved melody search algorithm, referred to as a symphony orchestra search algorithm (SOSA), is used to solve the proposed framework. The performance of the newly developed framework is numerically analyzed through implementing it to the standard 33-, 54-, 119- and 136-node distribution test networks. The numerical results well corroborate the sufficiency and profitableness of the proposed framework in achieving low vulnerability and high resilience to seismic risks.
•To develop a new effective graph theory-based topology assessment strategy to check the radial structure-related limitation.•To improve the tedious testing process of the radial structure in terms ...of computational rapidity and memory considerations.•To scrutinize the effectiveness and practicality of the graph theory-based topology assessment strategy in the short- and long-term horizons.
Power distribution networks (PDNs) are principally operated and planned in a radial—open-loop—structure to satisfy several techno-economic goals. It is, therefore, indispensable to develop new practical strategies to rigorously investigate the radial structure-related limitation in the operation and planning of the PDNs. In this study, after a thorough and critical review of existing strategies in the literature, a new effective graph theory-based topology assessment strategy (GT-ToST) is outlined to examine the radial structure-related limitation. Then, both the distribution branch reconfiguration (DBR) problem and the multi-stage joint distributed generation and distribution network expansion planning (DG&DNEP) problem (most appropriate for the short and long-term horizons, respectively) are employed to explore the feasibility and practicality of the newly proposed strategy compared to the existing ones. The proficiency of the proposed strategy is investigated for the DBR problem with a modified 33-bus PDN and a modified real-world 177-bus PDN in Rio de Janeiro, as well as for the DG&DNEP problem with a modified 27-bus PDN and a modified real-world 104-bus PDN in the northeast part of Brazil. The obtained results from the illustrative examples and case studies prove the effectiveness of the proposed GT-ToST compared to the existing strategies.
•A new reliability-constrained cost-effective model is developed for optimal sizing of an AHRS.•A new non-deterministic framework is proposed to deal with uncertainty in load demand and inherent ...characteristics of solar and wind generations.•The practical considerations pertaining to the optimal sizing of an AHRS are considered.•A new hybrid of the MD-BAT and MCSM is used to solve the proposed model.
During recent years, the optimal sizing of an autonomous hybrid energy system for microgrids operation management has been extensively explored. In this paper, with a new point of view, a reliability-constrained cost-effective model is developed to identify optimal sizing of an autonomous hybrid renewable system (AHRS). The significant aims of the proposed model are not only to address an exhaustive model for the AHRS by incorporating solar panel, wind turbine, diesel generator, and battery storage components, but also to implement practical considerations on the AHRS by considering its probabilistic characteristics. To do so, the proposed model takes into account total investment cost, the total fuel cost of the diesel generator, total maintenance cost and total expected load shedding cost in the optimization as four problem objectives subject to technical and operational constraints. A modified discrete bat search algorithm is widely employed to obtain the final optimal solution and followed by a Monte Carlo simulation method to handle non-deterministic characteristics pertaining to load demand, solar and wind generations. The obtained results of the proposed model are given and meticulously evaluated. These results show the feasibility and capabilities of the newly proposed model in the optimal sizing of an AHRS when compared with other approaches.
In this paper, the authors propose a new multi-objective decision making approach for optimal augmentation and expansion of transmission network. Fundamental elements of the proposed approach are ...value of reliability and electricity market. Investment Cost (IC), Total Congestion Cost (TCOC) and Social Welfare (SW) and also Average Load Interruption Cost (ALIC) are the four objectives considered in the optimization, while short-term and long-term constraints, are modeled as constraints. The proposed model is one of complicated non-convex optimization problem having a nonlinear, mixed-integer nature. Therefore, a new and robust hybrid Improved Harmony Search Algorithm (IHSA) and Quadratic Programming (QP) is used and followed by a Fuzzy Satisfying Method (FSM) to determine the final optimal solution. The feasibility and capabilities of the proposed approach are tested on the 6-machine 8-bus test system. The detailed results of the case studies are presented and thoroughly analyzed. The obtained results illustrate the sufficiency and profitableness of the newly developed method in augmentation and expansion of transmission network when, compared with other methods.
•It enhances the fault-current limiting capability of the PDGs, using the FCL-HTSCs, as a desirable alternative with low space requirements upon installation and high capacity.•It is a ...cost-minimization, mixed-integer nonlinear DEP framework for jointly reinforcing and/or installing substations, feeders, PL-/FCL-HTSCs, and DGs.•It models the stochastic nature of load demand, power production of the DGs, and capital expenditure budget using a potent MH-FIGDT.•It handles complexities via a powerful ICMSA empowered with a multi-computational-stage multi-dimensional multiple-homogeneous structure.
In this paper, the authors present a new stochastic multiyear framework for distribution expansion planning (DEP) that integrates fault current-limiting high-temperature superconducting cables (FCL-HTSCs) and distributed generations (DGs). The proposed framework, from a new perspective, is capable of analyzing and comparing the efficiency of the FCL-HTSCs with other, more generic cables under different short-circuit conditions. The objective function to be minimized isthe net present value of the total investment costs for reinforcing and/or installing substations, feeders, FCL-HTSCs, and DGs, as well as operation and maintenance costs. The framework also considers Kirchhoff’s current and voltage laws, operational limits on equipment capacities, voltage limits, as well as financial and discrete logical constraints. As a comprehensive overview, the authors have developed: (i) a graph-based bi-conditional scheme to ensure radiality requirements and (ii) a multi-horizon fractional information-gap decision theory (MH-FIGDT) to address the stochastic nature of anticipated load demand, power production of the DGs, and a capital expenditure budget. The resulting mixed-integer nonlinear optimization problem is solved by an integer-coded melody search algorithm (ICMSA) empowered with a multi-computational-stage multi-dimensional multiple-homogeneous structure that offers better performance in diversification and exploration. Case studies using the standard 27-node and realistic, large-scale 104-node distribution grids are provided here in order to show the effectiveness of the proposed framework. Based on simulation results, several conclusions can be drawn: (i) the MH-FIGDT critical cost and/or MH-FIGDT critical deviation coefficient chosen by the distribution grid operator play a key role in achieving robust expansion plans against the given uncertainty set; (ii) the incorporation of the FCL-HTSCs into the DEP problem offers a satisfactory compromise between the required amount and capacity of the equipment and total investment costs; (iii) the functionality of the FCL-HTSCs outperforms the generic cables in mitigating feeder congestion and excessive fault currents under normal and short-circuit conditions, respectively; and, (iv) the variations in fault currents caused by rising DG penetration are keep below the nominal interrupt rating of the circuit breakers, which speaks to the suitability of the proposed framework.
