Network Reconfiguration Methodology Research Articles

A Two-Stage EV Charging Planning and Network Reconfiguration Methodology towards Power Loss Minimization in Low and Medium Voltage Distribution Networks

The topic of power loss reduction in distribution systems has gained significant attention over recent years. Despite the efforts of the European Union towards the minimization of power losses, the decarbonization of the transport sector has raised several concerns, since charging overlaps of Electric Vehicles (EVs) can cause extensive power losses and power quality issues. Considering these, the present paper proposes a two-stage EV charging planning and Network Reconfiguration (NR) methodology, addressing the problem of power loss minimization in both Low-Voltage (LV) and Medium-Voltage (MV) Distribution Networks (DNs), respectively. In the first stage, considering the key role of the aggregator, the EV charging planning is applied to LV DN. In the second stage, the NR technique is applied to the MV DN, by taking into account the hourly power demand of LV DNs as obtained by the aggregators. The proposed methodology has been applied on a benchmarked MV network for which each node is represented by a real LV network. The results indicate that the proposed methodology could yield up to a 63.64% power loss reduction, in respect to the base scenario, i.e., no charging planning and no NR are applied.

Short-Term Forecasting-Based Network Reconfiguration for Unbalanced Distribution Systems With Distributed Generators

This article proposes a network reconfiguration methodology using repository-based constrained nondominated sorting genetic algorithm with preference order ranking for an unbalanced distribution system. The algorithm can accommodate the variable nature of load demand and distributed generator output. A mathematical multiobjective model is formulated to obtain the optimal topology for a whole day considering minimization of daily energy loss, energy not supplied, and cumulative current unbalance factor under the constraint of minimum switching action. A wavelet transform-based ARIMA model is used for wind speed forecasting and is proposed for solar irradiance and load forecasting as well. Hourly network reconfiguration (NR) is also performed, and a comparison is performed between hourly and whole-day NR. The proposed approach has been implemented on IEEE 34-bus and IEEE 123-bus systems to evaluate the effectiveness of the developed methodologies.

An Outage Risk Oriented Dynamic Distribution Network Reconfiguration Methodology Considering the Effects of Weather Conditions on Power Line Failure Rate

A dynamic network reconfiguration methodology considering time-varying weather conditions is proposed. The aim of the proposed methodology is to minimize outage risk. To fully reflect actual weather severity, a classification method for weather states based on weather variables analysis is presented. Considering time-varying nature of weather, an approach to determine the optimal time for reconfiguration by comparing reliability change between adjacent intervals is provided. Then, applying the Quantum Genetic Algorithm to solve reconfiguration optimization problem is introduced. Simulation results on the IEEE 33-node test systems show that the proposed dynamic reconfiguration method can reduce distribution network's outage risk. In addition, weather conditions have impacts on outage risk of distribution network and should be considered in reconfirmation problems.

Reconfiguration and Capacitor Placement of Radial Distribution Systems by Modified Flower Pollination Algorithm

This article proposes a combined methodology for network reconfiguration and optimal placement of shunt capacitors in radial distribution systems to reduce real power loss and enhance bus voltages. The power loss is reduced by network reconfiguration and capacitor placement, which in turn reduces a utility's loss of revenue. To ensure radial structure and avoid islanding of nodes, feasible tie-switch combinations are formed prior to the optimization process using a graph theory based method. The modified flower pollination algorithm uses a flower pollination process, an improved local neighborhood search method, and a dynamic switching probability approach to enhance the global search for optimization. The performance of this approach is tested on standard 33-bus, 69-bus, and 118-bus radial distribution test feeders. Results have been compared with previous methods reported in the literature, indicating the effectiveness of the combinatorial approach in terms of loss reduction, voltage enhancement, and cost saving.

Hierarchical Decentralized Network Reconfiguration for Smart Distribution Systems—Part I: Problem Formulation and Algorithm Development

This paper presents a hierarchical decentralized agent-based network reconfiguration methodology to minimize power losses for smart distribution systems. A novel formulation of the network reconfiguration problem is given in which the switch states are the decision variables, and a single-loop branch-exchange heuristic algorithm is used to solve the optimization problem. The entire distribution system is decomposed into subsystems based on the connectivity of areas, and an individual agent is assigned to each decomposed subsystem. A two-stage method is defined for coordinating the reconfigurations of decomposed subsystems. The optimal configuration of the entire system results from collaborations of individual agents, and the decentralized approach significantly reduces the computation time. A 118-bus distribution system is used as the example to illustrate the implementation of the method. The development of a demonstration system and more detailed simulation studies are given in Part II to further illustrate the application of the proposed decentralized approach.

Multiobjective Distribution Network Reconfiguration Considering the Charging Load of PHEV

Energy crisis and environmental pollution make the plug-in hybrid electric vehicle (PHEV) become a hot topic. This paper proposes a multiobjective network reconfiguration methodology based on quantum-inspired binary particle swarm algorithm that aims at alleviating the adverse impact of PHEV on distribution system. The methodology involves two steps: load level division and network reconfiguration for each load level. Two different charging patterns of PHEV are considered in this analysis: uncoordinated charging and coordinated charging. The simulation results show that the proposed methodology is an effective method to make the distribution network more flexible to accommodate PHEV.DOI: http://dx.doi.org/10.5755/j01.eee.19.5.1738

Network Reconfiguration for Electrical Loss Minimization

Increasing requirements of urbanization, industrialization and modernization demands further expansion and development of the national power grid and nonetheless, with a better efficiency and an enhanced voltage stability. The aim of this project is to conceptualize and realize an electric transmission and distribution network with improved efficiency and voltage stability that will contribute to the substantial reduction in the involved operational costs. Network Reconfiguration Methodology has been used. The study of this work was conducted on IEEE 14 bus network with Matlab tool using Newton-Raphson Method. The study also deals with how this technique can practically be implemented using Artificial Neural Network and sensors.

Extending market activities for a distribution company in hourly-ahead energy and reserve markets – Part I: Problem formulation

This work presents a novel hourly-ahead profit model for an active distribution company ( DISCO), a DISCO with high capacity level of connected DGs that can make selling proposals for the markets, in a pool-based system. The presented model engages DSICO in both energy producing and reserve providing activities. DISCO’s earnings from reserve market include the remuneration both for real-time generation and ready-for-service capacity. To achieve the optimal decisions for an active DISCO in the energy and reserve markets, a two-stage optimization model and associated mathematical formulations have been developed. The first subproblem extracts a single operating profile (a lumped financial model) of the whole distribution system, including DGs and ILs, at the connecting point to the upstream network. The second one determines the optimal values of decision variables (power and reserve commodities) to maximize the DISCO’s profit, in case such variables are accepted in the markets. In other words, it aims to optimally allocate the DISCO’s generating capability for proposing into the energy and reserve markets, from the DISCO’s perspective. It also proposes a profit-based network reconfiguration methodology for a multi-substation multi-feeder DISCO to increase DISCO’s ability to gain more benefits from the market activities. It conducts DISCO’s generating capabilities towards the proper substations to reap more probable benefits. It also introduces fast, simple, and straightforward algorithms for recognition and removal of configurations having loop and/or islanding parts in. Simulation results are given at the second part of the present work.

Extending market activities for a distribution company in hourly-ahead energy and reserve markets—Part II: Numerical results

The present work is to show the application and implementation of the algorithms and models proposed in part I. It also represents the simulation results of (a) extracting a lumped financial model (the aggregated model) of the distribution system with distributed generations ( DGs) and interruptible loads ( ILs), (b) distribution company’s ( DISCO’s) process of decision-making, based on the created financial model, on allocating its generating capability for internal usage and proposing to the hourly-ahead energy and reserve markets, and (c) a profit-based network reconfiguration methodology that increases the DISCO’s technical ability and directs its financial affairs towards more profitable transactions in the upcoming markets. The function of the algorithms used for detecting unfeasible configurations, namely loop path and/or isolated part in the network are shown and well exemplified. Influential factors in DISCO’s generating capability and in the coefficients of DISCO’s internal cost function (ICF) are investigated. The present study substantiates the ICF-based optimization method by comparing the relevant results with the results obtained based on the use of total cost function ( TCF). Several scenarios on market prices of energy and reserve and on the contingency probability factor pertaining to the real-time generation in reserve market are considered. Simulation results indicate that getting more economical benefits, DISCO may necessarily play different roles in the market and change the network configuration, at different hours.

05/02137 Supply- and demand-side effects of power sector planning with demand-side management options and SO 2 emission constraints

This work presents a novel hourly-ahead profit model for an active distribution company (DISCO), a DISCO with high capacity level of connected DGs that can make selling proposals for the markets, in a pool-based system. The presented model engages DSICO in both energy producing and reserve providing activities. DISCO’s earnings from reserve market include the remuneration both for real-time generation and ready-for-service capacity.To achieve the optimal decisions for an active DISCO in the energy and reserve markets, a two-stage optimization model and associated mathematical formulations have been developed. The first subproblem extracts a single operating profile (a lumped financial model) of the whole distribution system, including DGs and ILs, at the connecting point to the upstream network. The second one determines the optimal values of decision variables (power and reserve commodities) to maximize the DISCO’s profit, in case such variables are accepted in the markets. In other words, it aims to optimally allocate the DISCO’s generating capability for proposing into the energy and reserve markets, from the DISCO’s perspective.It also proposes a profit-based network reconfiguration methodology for a multi-substation multi-feeder DISCO to increase DISCO’s ability to gain more benefits from the market activities. It conducts DISCO’s generating capabilities towards the proper substations to reap more probable benefits. It also introduces fast, simple, and straightforward algorithms for recognition and removal of configurations having loop and/or islanding parts in. Simulation results are given at the second part of the present work.