Distribution Network Restoration Research Articles

A two-layer economic resilience model for distribution network restoration after natural disasters

Improving the resilience of energy networks and minimizing outages is crucial, making the development of self-healing strategies essential for ensuring a continuous power supply and boosting resilience. As decentralized prosumers become more integrated into smart grids, innovative coordination methods are required to fully leverage their potential and improve the system's self-healing capabilities. Hence, in this paper, we present a decentralized two-layer model for active distribution networks (ADNs) incorporating commercial energy hubs, Parking lots (PLs), hydrogen refueling stations, and mobile units (MUs). This model aims to maximize the flexible capacities of flexible prosumers under emergencies and includes a dynamic mechanism for transporting hydrogen to refueling stations via trucks. In the first layer of the model, the AND operator provides the required services to flexible prosumers, including commercial energy hubs, PLs and hydrogen refueling stations. During this layer, the movement paths of mobile units, such as battery-based mobile storage units (MSUs) and mobile hydrogen units (MHUs), are determined. In the second layer, prosumers independently plan and decide the extent of their service contributions. Subsequently, with the actual service capacities established, the AND operator re-optimizes the initial planning to finalize the system schedule and precise movement paths of the mobile units. The proposed model was tested on a modified 83-bus distribution network using the CPLEX solver in GAMS. Simulation results demonstrate a 54.9 % reduction in forced load shedding (FLS) due to the dispatch of mobile units and a further 84.4 %% reduction in FLS from leveraging the flexible capacities of commercial energy hubs and PLs.

Power distribution system restoration based on soft open points and islanding by distributed generations

Abstract A powerful and efficient program for restoring the electrical distribution system by effectively utilizing the maximum capabilities within the system, including soft open points, distributed generation resources, and network configuration changes, can significantly reduce both the quantity and duration of lost loads caused by permanent faults. In this research study, we address the issue of distribution network restoration with a focus on soft open points (SOPs) and intentional islanding using distributed generations. This problem is formulated as a constrained optimization problem in order to determine the optimal distribution network configuration, quality of intentional islanding through DGs, control function of SOPs, and amount of load shedding. The objective is to minimize lost load while minimizing switching operations and preferably minimal islanding. Given that this problem involves multiple complexities such as combinatorial nature, mixed-integer variables, non-linearity, non-convexity along with numerous variables and constraints; we employ an evolutionary method known as simulated annealing (SA) algorithm to solve it without any simplifications or assumptions about convexity. To enhance efficiency during implementation of SA algorithm, Kruskal’s algorithm is utilized for generating radial solutions which restricts search space to feasible solutions resulting in quicker attainment of high-quality optimal solutions. Finally, the outcomes of implementing the suggested approach on the 69-bus IEEE distribution system are presented and examined. It is demonstrated that by leveraging the potential of soft open points in load transfer control and network voltage regulation, along with utilizing intentional islanding capability provided by distributed generation resources, the restoration capability of the distribution system can be greatly enhanced.

Distribution Network Restoration Strategy Considering Mobile Energy Storage Systems

Abstract The increasing occurrence frequency of disruptive extreme weather events and the growing share of distributed resources further enhance the importance of restoration of distributed resource-assisted distribution networks. However, most distributed sources are not spatially flexible in scheduling, severely impacting the restoration performance of distribution networks. The emergence of mobile energy storage systems (MESS) provides temporally and spatially flexible resources. Based on the mobility of mobile energy storage, this paper proposes a distribution network restoration strategy considering MESS and prioritized restoration of critical loads. The restoration strategy is established aiming at maximizing weighted loads while satisfying multiple constraints. Specific operating characteristics of MESS are modeled and incorporated into the restoration model. The established restoration model is then reformulated into a mixed-integer second-order cone program. Case studies on a modified IEEE 33-node system verify the proposed restoration strategy.

The four misses of agricultural water husbandry in the Maghreb

AbstractRecurrent droughts plaguing the Maghreb geography have impacted dramatically on the yet scarce renewable water resources. This situation intensified tensions between water users, namely urban, industrial and agricultural sectors. At this point, agricultural water management in large‐scale irrigated schemes is under scrutiny since more than two‐thirds of the Maghreb mobilized water resources are used for agricultural purposes. However, this sector's performance is undermined by mismanagement, misuse, mispricing and misgovernance of agricultural water. From low irrigation water transport efficiencies, low water use efficiency at field level and low valuation of irrigation water by farmers, to nonreasoned pricing policies and lack of good governance, agricultural water husbandry is suffering a number of setbacks. This situation endangers the sustainable development of large‐scale irrigation schemes and could deprive Maghreb countries of the contribution of irrigated agriculture to countries' GDP and food security. These constraints were thoroughly analyzed, and a set of remedies was discussed that included restoration of water transport canals and water distribution networks, improvement of cropping systems, crop water use efficiency, extension services, reasoned subsidies and irrigation water pricing. Only by redirecting water husbandry in the large‐scale irrigation schemes, Maghreb countries can achieve sustainable development.

Research on distribution network restoration based on ant colony algorithm

Research on distribution network restoration based on ant colony algorithm

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

Transportable energy storage assisted post-disaster restoration of distribution networks with renewable generations

More frequent extreme weather events due to climate change impose significant challenges on the post-disaster restoration of distribution systems with significant penetration of renewable generations. To address this challenge, this paper investigates a restoration scheme for distribution networks integrated with renewable generations, and transportable energy storage systems moving along a transportation network, such as railway or road network, are used to support the network restoration after the fault event. To achieve this, for given fault conditions, topological reconfiguration is first facilitated via the soft open point (SOP) technology, and local renewable generators and loads are rapidly regrouped to form microgrids for post-disaster restoration. Then, assisted with transportable energy storage, the resources within the microgrids can be dispatched more efficiently, facilitating a more efficient post-disaster recovery process. To enable a cost-effective restoration of the distribution network, an economic model is formulated with the aim of minimizing the economic losses during the post-disaster restoration process. Case studies considering a significant number of failure scenarios show that the proposed transportable energy storage-assisted restoration scheme can effectively minimize costs during the post-disaster period considering various load types across different areas. This scheme not only achieves cost-effective post-disaster restoration but also ensures compliance with the constraints of the electrical networks, achieving up to 93.3% recovery cost reduction and 74.25% increase in critical load restoration.

Dynamic Restoration of Active Distribution Networks by Coordinated Repair Crew Dispatch and Cold Load Pickup

Dynamic Restoration of Active Distribution Networks by Coordinated Repair Crew Dispatch and Cold Load Pickup

Impact on Long Duration of Overvoltage Due to Back-Feed Restoration of Distribution Network

In power system, power outages can be critical; if the environment and public safety within risk situation. Therefore, restoration power is needed to respond on system distribution to reduce the power restoration time and making the system reliable and efficient. Backfeeding using a nearby feeder in a power system is proposed in this research. When a power outage occurred, the faulted area is isolated from the system and searching available nearby feeders that can restore the outage area without any violation. However, analysing the effects of using a nearby feeder for back feeding is needed to avoid voltage violations. This paper analyses the voltage during the healthy and faulted condition, the impact of using a nearby feeder for backfeeding for a full load, half load and during no-load conditions are examine and also determine the maximum increment limitation of a load during back-feed if a qualified feeder is selected. Newton Raphson method is applied to calculate the power flow in the system and observe the stability of backfeed configuration. The results show the highest voltage supply occur during no load followed by half load and lastly during full load. The maximum voltage increment of load on backfeed is determined to be 0.95pu as an ideal voltage value.

Coordinated Islanding Partition and Scheduling Strategy for Service Restoration of Active Distribution Networks Considering Minimum Sustainable Duration

Coordinated Islanding Partition and Scheduling Strategy for Service Restoration of Active Distribution Networks Considering Minimum Sustainable Duration

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

Evaluation of fixed assets of electric power enterprises-operators of the distribution system under the conditions of the post-war reconstruction of Ukraine

The article is devoted to the assessment of the fixed assets of electric power companies-operators of the distribution system under the conditions of the post-war reconstruction of Ukraine. Attention is focused on areas of criticism of the concept of historical costs. Considerable attention has been paid to the advantages and disadvantages of the approaches of researchers to fair value asset valuations and cost asset valuations. The advantages and disadvantages of using fair value when making management decisions are highlighted. The sectoral features of the assessment were considered for the purpose of forming investment projects in the renewal of fixed assets of electric power enterprises-operators of the distribution system and the development of the distribution system. The majority of electric power enterprises-operators of the distribution system choose a revaluation model for classes of fixed assets and carry out revaluations of fixed assets. The algorithm for determining the asset valuation base with the aim of transitioning to stimulating regulation (RAB-regulation) was studied. It was found that the basis of asset valuation can be the market value or the residual value of replacement (reproduction). The expediency of applying the concept of asset impairment assessment in electric power enterprises-operators of the distribution system has been established. A method of testing for the reduction of utility of fixed assets of electric power companies-operators of the distribution system is proposed, with the help of which internal users will make decisions regarding their further safe operation and the need to find sources of investment in the restoration of distribution networks.

Distribution network restoration supply method considers 5G base station energy storage participation

This paper proposes a distribution network fault emergency power supply recovery strategy based on 5G base station energy storage. This strategy introduces Theil's entropy and modified Gini coefficient to quantify the impact of power supply reliability in different regions on base station backup time, thereby establishing a more accurate base station's backup energy storage capacity model that can fully utilize the base station's energy storage resources to participate in the emergency power supply of distribution network faults. First, the optimal Copula function in each cycle is determined through the Akaike information criterion and squared Euclidean distance to establish a wind power-photovoltaic output scenario. Secondly, the traditional Gini coefficient is modified using the weighted average node degree and influence rate indicators. A comprehensive vulnerability model is established through the modified Gini coefficient and Theil's entropy indicators. Based on the comprehensive vulnerability model, a backup energy storage time model and a modified backup energy storage capacity model of the base station affected by power supply reliability are established. Thus, the callable energy storage capacity of base stations in different areas is obtained. Finally, a two-stage robust optimization model is introduced to minimize system operating costs to solve the volatility of 5G base station communications and wind-solar output, thereby establishing an emergency power supply recovery model for base station energy storage and wind-solar output. Simulated with the improved IEEE-33 node model, the results show that the proposed base station's energy storage model improves the utilization of the base station energy storage resources and, at the same time, effectively reduces the loss of load during the fault phase of the distribution network and improves the absorption of the PV output.

Distributed Optimization for Autonomous Restoration in DER-Rich Distribution System

Autonomous service restoration (ASR) of active distribution network (ADN) reduces service restoration time with the help of measurement devices, smart switches and distributed energy resources (DERs) considering the system's operational and radiality constraints. Restoration scheme can be deployed in both centralized and distributed manner. However, with increasing data points, the requirement for measurement availability at the control center for the decision support makes centralized optimization challenging. The decomposition and coordination scheme of distributed algorithms enhances its ability to solve large scale optimization problems. Moreover, distributed optimization enables robustness, scalability and resiliency compared to centralized optimization. In this work, a) the distributed ASR problem is solved using a novel penalty-driven distributed alternating direction method of multipliers algorithm (PD-ADMM), b) a switch level decomposition and coordination technique is proposed, c) load restoration, DER utilization are considered directly and radiality of ADN is enforced using commodity flow model. The applicability of the algorithm is validated using modified IEEE 33-bus, IEEE 123-bus and 1069-bus test systems for contingency cases, communication failure, scalability, accuracy and sensitivity to number of partitions, starting points, change in DER / solar generation.

Stochastic restoration of distribution networks with high penetration of solar PV systems through a generic switching order mechanism

The process of fault isolation and service restoration (FISR) is an essential component of the implementation of distribution automation. By using FISR to determine the switching order, whether manually or remotely, the network's reliability is significantly enhanced in comparison to that of conventional switching. On the other hand, it is impossible to refute the exponential development of distributed energy resources such as photovoltaic (PV) generators. This paper introduces a general FISR for distribution networks with high penetration of solar PV systems. The proposed FISR strategy is an optimum switching sequence with the goal of reaching the best restoration hour before any likely fault occurrence. The proposed framework takes into account the inherent uncertainty in network demand and renewable generation in addition to the innovative mathematical programming model for the switching order. In addition, this stochastic programming handles the radiality constraint in the restoration process by creating a fictional layer as a means of reducing the complexity of the modeling. Moreover, the impact of PV penetration level on the optimal switching order for heavy-loaded distribution feeders is addressed and investigated.

Critical loads restoration of distribution networks after blackout by microgrids to improve network resiliency

Critical loads restoration of distribution networks after blackout by microgrids to improve network resiliency

Evaluating stakeholder structure and private actor involvement on the distribution of relief goods considering a partly centralised decision

ABSTRACT Relief distribution involves numerous stakeholders with various roles and different structures regarding stakeholders’ coordination. This paper proposes a model to evaluate various stakeholder structures for distributing relief goods. Unlike previous research, this model evaluates the coordination structure, assuming no single centralised decision-maker exists. The proposed model is developed based on the decomposition-based framework, assuming a partly centralised decision. The proposed model also integrates road network restoration into the model by capturing the disrupted road network. The role of the private sector is elaborated by exploring the impact of private business involvement in food-related distribution and road network restoration. The proposed model is applied to an actual case, namely the Palu earthquake and tsunami in 2018. We found that the multifocal structure performs better in distributing relief goods. Furthermore, the involvement of the private sector succeeds in minimising the unsatisfied demand.

Co-Evolution Framework Between Humans and Simulations: Planning Post-Disaster Restoration of a Water Distribution Network

This paper developed a new framework for better knowledge management through computational simulations, enabling both human knowledge creation and updating simulation models. The framework was developed based on the concepts of the socialization, externalization, combination, and internalization (SECI) model, and it contains a structured workshop that includes the four types of Ba the model requires. To evaluate this framework, the planning of post-disaster restoration of water distribution networks was employed as a case study. In addition, a new optimization method was developed using empirical heuristics obtained from practitioners, aiming for meaningful feedback from the practitioners working in a water management company. Based on our simulation, three workshops were conducted to create new knowledge, and new features were added to the simulation. In these workshops, practitioners performed simulation-based training in planning the restoration and then discussed their decisions. Afterward, it was concluded that the proposed framework was sufficient for updating the simulation. However, it required additional methods to provide practitioners with opportunities to obtain new insights.

Coordination of network reconfiguration and mobile energy storage system fleets to facilitate active distribution network restoration under forecast uncertainty

The active distribution network (ADN) shows great potential for use in network restoration services, given its ability to actively control the network topology, distributed generation (DG) outputs, and demand response (DR) resources. However, its utility may be limited due to the geographical dispersion of DG and DR resources when applied to natural disasters such as windstorms, earthquakes, and floods. In addition, the increasing use of renewable energy creates fluctuations and uncertainties, hindering ADNs from realizing reliable energy scheduling during disasters. Mobile energy storage system (MESS) fleets can be used to economically provide flexible emergency power supply for network restoration services. MESSs can also hedge against load and DG output forecast risks. This article proposes a novel coordinated network reconfiguration and MESS fleets dispatching model considering the uncertainty in DG output and load forecasts to increase the resilience of the ADN after disasters. The MESS traveling strategy is modeled by an extended transit delay model. Then, a novel deterministic network restoration model incorporating the MESS, stationary energy storage system, DG, DR, and network reconfiguration is proposed and programmed using mixed-integer linear programming. Then, an ellipsoidal uncertainty set is employed to describe the uncertainty of load and DG output forecasts, and a robust network restoration model is proposed based on the deterministic one. The proposed deterministic and robust network restoration models are verified on a 59-bus rural distribution system in China.

A Tabu-search-based Algorithm for Distribution Network Restoration to Improve Reliability and Resiliency

Fault restoration techniques have always been crucial for distribution system operators (DSOs). In the last decade, it started to gain more and more importance due to the introduction of output-based regulations where DSO performances are evaluated according to frequency and duration of energy supply interruptions. The paper presents a tabu-search-based algorithm able to assist distribution network operational engineers in identifying solutions to restore the energy supply after permanent faults. According to the network property, two objective functions are considered to optimize either reliability or resiliency. The mathematical formulation includes the traditional feeders, number of switching operation limit, and radiality constraints. Thanks to the DSO of Milan, Unareti, the proposed algorithm has been tested on a real distribution network to investigate its effectiveness.