Service Restoration In Distribution Networks Research Articles

Dynamic Service Restoration of Distribution Networks With Volt-Var Devices, Distributed Energy Resources, and Energy Storage Systems

Dynamic Service Restoration of Distribution Networks With Volt-Var Devices, Distributed Energy Resources, and Energy Storage Systems

Optimal Coordination of Transportable Power Sources and Repair Crews for Service Restoration of Distribution Networks Considering Uncertainty of Traffic Congestion

Optimal Coordination of Transportable Power Sources and Repair Crews for Service Restoration of Distribution Networks Considering Uncertainty of Traffic Congestion

Research on rolling co-optimization of fault repair and service restoration in distribution network based on combined drive methodology

Research on rolling co-optimization of fault repair and service restoration in distribution network based on combined drive methodology

Decentralized restoration scheme for distribution system with networked microgrids

Recent increases in the frequency of natural disasters and cyberattacks underscore the significance of enhancing outage management and service restoration in distribution networks. Traditionally, the distribution system operator (DSO) is responsible for service restoration, including locating damaged components, reconfiguring the network, and scheduling distributed generators (DG). However, the traditional single entity in the distribution network is being replaced by several individual entities with the growth of self-governed microgrids (MG), including the DSO and microgrid operators (MGO). Due to privacy concerns, these entities will schedule their resources in pursuit of their individual objectives, while still being physically connected. In this paper, a decentralized method is developed to model the independent service restoration of the DSO and MGOs while describing the interaction between them. Decision authority is given to each entity to autonomously schedule and operate the generation and load demand. Each entity solves its own optimization problem to maximize its own served loads based on the resources it possesses and the information it shares. The proposed algorithm uses an iteration procedure to negotiate among different entities and achieve consensus. A test case of an IEEE 33-node test system with multiple networked MGs is studied to investigate the feasibility and effectiveness of the proposed decentralized restoration scheme.

Resilience-Oriented Co-Deployment of Remote- Controlled Switches and Soft Open Points in Distribution Networks

Soft open points (SOPs) can perform load transferring and voltage support, helping to expand the range of service restoration in distribution networks (DNs) under fault scenarios. In addition, in the field of DN restoration, SOPs are usually controlled in coordination with switch actions (e.g., the network reconfiguration). However, in the planning level, the coordinated deployment of SOPs and remote-controlled switches (RCSs) has never been studied in the literature. To this end, for the first time, this paper proposes a co-deployment framework for SOPs and RCSs incorporating active management of flexible resources for resilience improvement in DNs, in which the coupled multiple recovery stages are also modeled and included. The objective is to minimize the investment cost of SOPs and RCSs, along with the cost caused by de-energized loads, with the consideration of exhaustive DN operation constraints over proactive islanding, degradation, isolation and restoration stages. Furthermore, resilience-cost tradeoff is analyzed to help DN managers determine equipment investment plans. The formulated model is further transformed into a mixed-integer second-order cone programming model that can be thus efficiently solved. Simulation results on modified IEEE 34-node and IEEE 123-node test systems verify the effectiveness of the proposed model.

A Hierarchical Restoration Mechanism for Distribution Networks Considering Multiple Faults

Service restoration of distribution networks in contingency situations is one of the highly investigated and challenging problems. In the conventional service restoration method, utilities reconfigure the topological structure of the distribution networks to supply the consumer load demands. However, the advancements in renewable distributed generations define a new dimension for developing service restoration methodologies. This paper proposes a hierarchical service restoration mechanism for distribution networks in the presence of distributed generations and multiple faults. The service restoration problem is modeled as a complicated and hierarchical program. The objectives are to achieve the maximization of loads restored with minimization of switch operations while simultaneously satisfying grid operational constraints and ensuring a radial operation configuration. We present the service restoration mechanism, which includes the dynamic topology analysis, matching isolated islands with renewable distributed generations, network reconfiguration, and network optimization. A new code scheme that avoids feasible solutions is applied to generate candidate solutions to reduce the computational burden. We evaluate the proposed mechanism on the IEEE 33 and 69 systems and report on the collected results under multitype fault cases. The results demonstrate the importance of the available renewable distributed generations in the proposed mechanism. Moreover, simulation results verify that the proposed mechanism can obtain reasonable service restoration plans to achieve the maximization of loads restored and minimization of switching operations under different faults.

Research on Rolling Co-Optimization of Fault Repair and Service Restoration in Distribution Network Based on Combined Drive Methodology

Research on Rolling Co-Optimization of Fault Repair and Service Restoration in Distribution Network Based on Combined Drive Methodology

Service Restoration in Distribution Networks Using Available Data Including Uncertainty

The growth in penetration of photovoltaic generation systems (PVs) makes it difficult to reconfigure electrical power distribution networks, including service restorative operations. This is because distribution network operators cannot monitor or control the PVs, and this brings an additional uncertainty in available data that the operators must rely on. The authors focus on the service restorative operations and propose a problem framework and its solution method that finds the optimal restoration configuration under extensive PV installation. The traditional service restoration problems require accurate data on load sections; however, it is not practical in the distribution networks where PVs are extensively installed. Based on this background, the robust optimization and the two-stage stochastic programming are applied in the proposed formulation to address the PV-originated uncertainty using only readily available data. Through numerical simulations and discussion on their results, the validity of the proposal is verified.

Multi-Objective User Preference Enabling Method for Service Restoration in Distribution Networks with High Renewable Energy Penetration

Service restoration (SR) in distribution networks by nature is a multi-objective optimization problem. To solve the multi-objective SR and to ensure sufficient available delivery capability for delivering renewable energy, a user preference enabling (UPE) method is proposed in this paper. The proposed method is user-oriented, allowing a user’s preferred solution over a range of each objective function value to be achieved. The proposed UPE method can adopt each user’s specific preference over each objective function, allowing the user to directly place a preference for each objective function without compromising their independence from each other. If the user preference problem has no solution, the proposed method will identify the non-existence of a solution and suggest a remedy scheme to recover a solution. To achieve its computational efficiency, the proposed UPE method contains a discrete optimization stage and a relaxation and correction stage to solve the multi-objective SR problem, which has a large number of binary variables. A user-preferred solution that truly meets the user's needs for each objective is thus fast obtained. The effectiveness and flexibility of the proposed UPE-based method is evaluated on large distribution networks with multiple scenarios.

A systematic approach to service restoration in distribution networks

The progressive automation of distribution networks, along with the large amount of information gathered by smart devices, allow Distribution Management Systems (DMS) to be endowed with decision-making tools aimed at optimizing the service restoration process. This article presents an algebraically-assisted, heuristic procedure intended to guide the DMS operators in the selection of switching maneuvers during fault isolation and supply restoration of faulted MV feeders. At each step, the proposed methodology determines, among the possible switching sequences, the one that minimizes the impact of the interruption on unserved loads. The probabilistic character of the addressed problem involves the use of several statistical parameters, such as equipment failure rates, expected traveling times between network nodes, etc. The procedure is illustrated on a tutorial example and a real distribution system. The results are very close to those obtained with more exhaustive search procedures, at much shorter execution times, which makes the proposed approach also suitable for reliability-centered investment analysis.

系統情報の不確実性を考慮した配電ネットワーク事故復旧に関する研究

系統情報の不確実性を考慮した配電ネットワーク事故復旧に関する研究

Voltage Control Method Utilizing Solar Radiation Data in High Spatial Resolution for Service Restoration in Distribution Networks with PV

AbstractThis paper proposes a voltage control method during service restoration in the distribution networks with photovoltaic (PV) generator systems. In the current distribution automation system (DAS) process in Japan, voltage dips and surges occur during service restoration because PVs are disconnected simultaneously after a fault and subsequently reconnected after service restoration. However, in the current DAS, voltage regulators such as an on-load tap changer (OLTC) and step voltage regulators (SVRs) are not controlled during service restoration. The proposed DAS estimates the voltage in a distribution network during service restoration, and it controls the tap position of OLTC and/or SVRs according to the predicted voltage. The numerical simulation results using a real-world distribution system model on a real map and PV output profiles derived by actual square kilometer solar radiation data will be shown. Those results indicate that the proposed DAS prevents voltage deviation that occurs as long ...

Consideration of healthy MV busbar feeders in the service restoration of distribution networks

The service restoration application for severe power outages involving the consideration of the healthy medium voltage (MV) busbar feeders of the HV/MV substation in de-energised area is presented in this paper. The MV busbar feeders consideration is achieved by introducing additional coefficient to the heuristic graph-based service restoration algorithm. Minimisation of unsupplied load is the primary objective of the proposed service restoration application. Secondary objective is the reduction of the number of switching actions. The proposed approach involves the assignment of the weighting coefficients de-energised distribution network branches. The consideration of the healthy MV busbars feeders significantly improves the service restoration algorithm performance.

Service restoration in distribution networks using combination of two heuristic methods considering load shedding

Two heuristic methods are proposed to find an effective and fast solution in modern power distribution networks. For solving the service restoration problem in distribution networks, switch selection indices based on an analytic approach and a practicable heuristic graph-based method are given. The formulation of the problem includes four different objective functions: 1) maximizing the total load restored; 2) minimizing the number of switching operations; 3) maximizing the top priority restored load; 4) minimizing load shedding. A suitable evaluation of switch indices is used for all candidate tie switches (TSs) in the network to find the best solution and decrease the number of switching operations. A new graph-based approach is utilized for finding the best sectionalizes switch (SS) and minimizing the voltage drop. The accuracy and the validity of the approach are tested in two standard electrical distribution networks. The results of the approach are used for IEEE 69-bus and IEEE 119-bus test case.

Service Restoration of Distribution Networks Considering Switching Operation Costs and Actual Status of the Switching Equipment

Minimization of the de-energized consumers load and reduction of the service restoration costs are considered in the proposed heuristic graph-based approach for finding the solution of the service restoration in distributed networks. The approach is based on the logic of the modified Prim's algorithm that finds the minimum spanning trees (i.e., a forest). Operation costs including an actual status (“open” or “close”) of the switching equipment in a de-energized area is represented by the switching cost coefficients. The cost coefficients are assigned to all branches in a de-energized area. The switching action is performed by switching equipment with minimal switching costs coefficient in each iteration of the algorithm. The results confirm that the service restoration costs are decreased by the consideration of the actual status of the switching equipment.

Fast Service Restoration of Multi-Source Active Distribution Network with Microgrids and Electric Vehicles

The increasingly serious energy crisis and environmental pollution problems promote the large-scale application of microgrids (MGs) and electric vehicles (EVs). As the main carrier of MGs and EVs, distribution network is gradually presenting multi-source and active characteristics. A fast service restoration method of multi-source active distribution network with MGs and EVs is proposed in this paper for service restoration of distribution network, which takes effectiveness, rapidity, economy and reliability into consideration. Then, different optimal power flow (OPF) models for the service restoration strategy are constructed separately to minimize the network loss after service restoration. In addition, a genetic algorithm was introduced to solve the OPF model. The analysis of the service restoration strategy is carried out on an IEEE distribution system with three-feeder and eighteen nodes containing MGs and EVs, and the feasibility and effectiveness are verified

Multi-fault service restoration in distribution networks considering the operating mode of distributed generation

This article presents an electric power service restoration model for distribution networks considering distributed generation (DG). The optimization model is based on genetic algorithms (GA), using the fundamental loops of the network as the topology selection mechanism. The algorithm was tested on IEEE test systems with 17 and 33 buses. Results show the advantages of DG in the restoration process, the best operating mode of the DG and the effectiveness of the study technique.

A heuristic method for feeder reconfiguration and service restoration in distribution networks

A sequential switch opening method is proposed for minimum loss feeder reconfiguration in this paper. The algorithm is further extended for service restoration. The method is based on the branch power flow rather than the current flow as reported in earlier methods. The final algorithm arrives at opening of a branch in a loop carrying minimum resistive power flow to make the network radial causing minimum loss. The test results reveal that the proposed method yields optimal configuration with reduced computation burden and better restoration plan.

Multiobjective service restoration in distribution networks using an evolutionary approach and fuzzy sets

In this article, the service restoration (SR) problem in electrical distribution networks is dealt with using an evolutionary strategy (ES) with a fuzzy definition of the conflicting objectives. The normal operation status allows the remote control of tie-switches, of capacitor banks and load connection. When a permanent fault occurs, the same remote control actions can be performed with the aim of restoring the service in the concerned areas. The status of these remotely controllable elements is the boolean optimisation variables for the SR problem. Besides this, here the SR problem is dealt with in a multiple objectives (MO) formulation. Indeed, the power losses’ term is considered as a further objective to be minimised, together with the primary objective of maximising the number of supplied loads. Generally, the MO formulation of an optimisation problem requires a unique expression for the global objective function. In this particular case, the used ES approach necessarily requires the definition of a ‘global performance’ index, which is derived on the basis of the fuzzy sets theory, outperforming the weighed sum formulation of the same problem. After a brief discussion on the SR problem and a short review of the state-of-art on the topic, the proposed ES and the fuzzy MO formulation of the SR problem is presented in detail. Results obtained using this procedure applied to a test system are presented and discussed.

A new network reconfiguration technique for service restoration in distribution networks

Whenever a fault occurs in a particular section of a distribution network and on isolation of the fault, some of the loads get disconnected and are left unsupplied. Service should be restored to these affected load points as quickly as possible through a network reconfiguration procedure. A new and efficient technique is presented in this paper for this purpose. Network reduction and determination of the interested trees of the reduced network by a specially developed algorithm for finding the required restorative procedures, are the main contributions of this paper.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>