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This paper proposes a new decentralized data-driven load res-toration (DDLR) scheme for transmission and distribution (TD) systems with high penetration of wind power. Robust DDLR models are constructed in order to handle uncertainties and ensure the feasibility of decentralized schemes. The Wasserstein metric is used to describe the ambiguity sets of probability distributions in order to build the complete DDLR model and realize computationally tractable formulation. A data-driven model-nested analytical target cascading (DATC) algorithm is developed to obtain the final load restoration result by iteratively solving small-scale mathematical models. The proposed DDLR scheme provides load restoration results with adjustable robustness, and performance efficiency is independent from the amount of data. The DDLR scheme makes full use of the available data while respecting information privacy requirements of independently operated systems, and ensures the feasibility of the decentralized load restoration strategy even in the worst-case condition. The effectiveness of the proposed method is validated using a small-scale TDS and a large-scale system with the IEEE 118-bus TS and thirty IEEE-33 DSs, showing high computational efficiency and superior restoration performance.

The paradigm shift in the configuration of the power system in Europe and the United States away from large conventional synchronous generators to small generating units distributed over large geographical areas, many of which are powered by intermittent renewable resources, has a major effect on various aspects of system operations, most importantly dispatch and commitment processes. This article discusses the challenges for power system restoration and how to meet those challenges.

Soft open points (SOPs) have the ability to regulate the power flow among their terminals in a continuous manner, which can solve the problems brought by the synergy of distribution networks and distributed generation, and improve the system reliability and power supply capability. To address the current lack of quantitative measurement on the effects of SOPs, the power supply capability evaluation method for active distribution networks (ADNs) with four-terminal SOPs considering reliability is proposed. Firstly, the topology and configuration modes of four-terminal SOPs are studied, and their control modes are investigated in normal operation and supply restoration conditions. Then, using the feeder partition method, the effects of four-terminal SOPs on the power outage duration of different load areas after a fault are studied, and the reliability evaluation process for ADNs with four-terminal SOPs is developed based on the quasi-Monte Carlo method. Later, with reliability as the main constraint, the power supply capability evaluation model for ADNs with four-terminal SOPs is established, and the solution algorithm is proposed. Finally, the effectiveness and applicability of the method proposed are verified through a case study.

Current electricity market across the globe faces the power outage problems due to the various operating and maintenance issues. This paper presents a summary of the past and present literature which illustrates the various causes contributing to blackout. Throughout this article, the power system service restoration (PSSR) is explored in more depth regarding its limitations, operational restrictions and the problems present in the current PSSR schemes along with the numerous methodologies established by earlier researchers working in this area.

An advanced distribution management system (ADMS) is a software platform that supports grid management and decision support applications to address the growing operational challenges faced by power distribution systems to ensure reliable, resilient, and economic operations. In this paper, a fault location, isolation, and restoration (FLISR) application is developed and integrated with an open-source standards-based platform for ADMS application development viz. GridAPPS-D, developed by Pacific Northwest National Laboratory (PNNL). Also, a new distribution system restoration (DSR) algorithm, an integral part of the FLISR application, is proposed that utilizes backup feeders and distributed generators (along with intentional islanding features) to restore critical loads. The proposed application is developed in python and is tested on a modified IEEE 8500-node test system using the GridAPPS-D platform. The successful deployment of the FLISR application on the GridAPPS-D platform provides a proof-of-concept for the adoption of new and advanced ADMS applications to support future power distribution systems.

This article presents a new strategy of active synchronization of an island micro-grid and the utility grid (UG) without measurements at the point of common coupling (PCC). This strategy is based on the assistance of Ethernet communication, GPS pulse-per-second device synchronization, and droop control parameter shift. A strategy with Ethernet-assisted synchronization is used instead of synchronization with dedicated low-bandwidth communication. This strategy is based on exchanging data between two proposed devices: synchronization data sender (SDS) and synchronization data controller (SDC). The SDS calculates the UG voltage parameters and sends these data to the SDC device. The SDC is responsible for receiving synchronization data and calculating droop control parameter shift. The use of GPS-based device synchronization adds very stable and accurate measurements of synchronization parameters that correspond to the stable synchronization signal. As this strategy uses droop control method parameter change, all distributed generators share loads adequately. This strategy introduces the possibility to remove the need for measurement of voltage directly on the switch location. The proposed devices could be connected even a long distance from the PCC. The strategy also introduces the possibility of working in synchronism with the main grid despite the island mode of the micro-grid. This introduces the possibility to connect the micro-grid at the same moment as fault clear or maintenance end.

Power system restoration must be accomplished as soon as possible after a blackout. In this process, available black-start (BS) units are used to provide cranking power to non-black-start (NBS) units so as to maximize the overall power system generation capacity. This procedure is known as the generation start-up problem, which is intrinsically combinatorial with complex non-linear constraints. This paper presents a new mixed integer linear programming (MILP) formulation for the generation start-up problem that integrates non-conventional renewable energy sources (NCRES) and battery energy storage systems (BESS). The main objective consists of determining an initial starting sequence for both BS and NBS units that would maximize the generation capacity of the system while meeting the non-served demand of the network. The nature of the proposed model leads to global optimal solutions, clearly outperforming heuristic and enumerative approaches, since the latter may take higher computational time while the former do not guarantee global optimal solutions. Several tests were carried out on the IEEE 39-bus test system considering BESS as well as wind and solar generation. The results showed the positive impact of NCRES in the restoration processes and evidenced the effectiveness and applicability of the proposed approach. It was found that including NCRES and BESS in the restoration process allows a reduction of 24.4% of the objective function compared to the classical restoration without these technologies.

The share of renewables in the power system is increasing rapidly. Large offshore wind power plants (OWPPs) are developed at a high pace and conventional fossil fuel-based plants are decommissioned. Consequently, there will be a risk of insufficient amount of power plants providing black start functionality for system restoration after a black out. This paper proposes a STATCOM with a battery energy storage that is located at the point of common connection to an OWPP that together can provide a reliable black start service to the power grid. The concept is demonstrated by using time domain simulations in PSCAD. The STATCOM functionality provides fast and dynamic reactive power management and the battery unit provides active power balancing capability to maintain the frequency within a tolerable range specified by the system operator. The simulation results fulfill the success criteria for the black start and confirm its feasibility for practical implementation.

During power system restoration following a blackout, it is necessary to quickly restore as many generator units as possible to accelerate the speed of the system restoration. Considering that wind power of large capacity has the advantages of fast start-up speed, flexible access method etc., its participation in power system restoration can speed up grid recovery. However, due to wind power fluctuations, the integration of wind power during system restoration may impact the frequency of the restored system. In severe cases, the frequency of the restored system will exceed the limit, which will threaten the safety of the restored system. Consequently, the power reference of the wind farm needs to be optimised during the system restoration. Therefore, an optimisation model of power reference of the wind farm in power restoration based on the fuzzy chance constraints model was proposed in this study. The model maximises the power support of a wind farm on the basis of the safety of the restored system. Simulation results show that this method can provide more power under the condition that the system safety is guaranteed.

Single-clamp sub-module (SCSM) combining the cost and technological advantages has become one of the next modular multilevel converter (MMC) sub-module topologies in response to DC fault aspect. It describes the topological structure and working conditions based on SCMMC (Single-Clamp MMC) and proposes the three-stage start-up processes of SCMMC. The paper has made a detailed study on the black-start scheme of the blackout terminal converter when SCMMC-HVDC is used in grid black start. The active-side SCMMC orderly rotation trigger control strategy and the passive-side SCMMC orderly rotation bypass control strategy are proposed targeted. The paper proposes the corresponding start-up procedures for the SCMMC-HVDC system. At last, simulation models are established in PSCAD/EMTDC, the simulation results have validated the efficiency of the proposed black-start scheme for the converter of the blackout terminal.

Thanks to the solid standards and principles of design and restoration planning after a blackout, power systems in developed economies generally show a high level of resiliency. Nevertheless, this power system restoration practice stronglyrelies on conventional power plants, e.g. large thermal power plants. As future global goals aim at reducing the use of fossil fuels and lowering carbon-dioxide emissions, conventional power plants are often taken out of operation. These are characterised by slow start-up times and considerable use of fossil fuels. In this context, large offshore wind farms (OWFs) show potential as renewable-based black start (BS) service providers. These can be equipped with a self-starter, e.g. synchronous generators or innovative power-electronic-based converters, such as battery energy storage systems (BESSs) and/or grid-forming wind turbines in order to BS the system. Additionally, state-of-the-art complementary devices such as STATCOMs or synchronous condensers can help with dynamic regulation and support the OWF both in island operation and BS. In this paper, an overview of different system configurations for OWF BS is presented. Firstly, the requirements for BS from non-conventional power plants are outlined. Afterwards, the challenges faced by OWFs to fulfil these requirements are identified. Finally, different solutions for system configurationto equip OWFs for BS are proposed.

This paper presents a model for the study of bottom-up power system restoration tests. The model is built for quick and suitable validation of power-frequency correlation during a restoration test, the most stressed process into a system with low regulation energy. All involved components are modelled by SISO systems describing both power generation controls and load behaviours. The simulation results are widely discussed through the analyses of four load scenarios, with the aim of scanning all possible worst cases in terms of load steps.

In this paper, a procedural approach for studying the feasibility of a restoration backbone is presented. The approach uses a Simulink model for the study of frequency and voltage dynamic behaviors in order to obtain a backbone simulation for different load scenarios. The method is then applied to a restoration path involving a portion of Italy transmission grid, focusing on the study of power-frequency behavior. Some details on the modeling of load and distributed generation are given, so to represent the real behavior of a primary substation in terms of active power transit.

Several parallel restored subsystems exist in the last stage of the build-up restoration process of bulk power systems. The whole system restoration is completed when these subsystems are reconnected and their internal loads are recovered. This paper proposes a robust distributed coordination scheme to achieve reconnection and load recovery of parallel restored subsystems in wind power penetrated transmission systems. First, robust distributed restoration models are constructed considering individual subsystems under uncertain conditions. Then, an inner-outer nested upper-lower (IOUL) iterative algorithm is developed to solve the constructed models. The robust distributed coordination can be realized according to convergence. The proposed algorithm solves the complex non-convex model with uncertain variables by iteratively solving the small-scale mixed-integer linear programming (MILP) problem. The robust distributed restoration scheme allows independent decision-making within subsystems and ensures the feasibility of the distributed restoration strategy under uncertain conditions. The effectiveness of the proposed method is validated using three interconnected 6-bus systems and the IEEE 118-bus system, showing improved computational efficiency and restoration acceleration.

The increasing penetration of wind energy poses great challenges to the operation of power systems in normal and emergency states. However, energy storage technologies can help accommodate wind power uncertainty and variability due to their flexible characteristics. This paper focuses on the restoration phase, and provides a novel coordination strategy of wind and pumped-storage hydro (PSH) units for a faster and reliable self-healing process. The wind-PSH assisted power system restoration is formulated as a two-stage adaptive robust optimization problem. The first-stage problem determines the start-up sequence of generators and the energization times of transmission paths; and the second-stage problem decides load pickup sequences, wind power dispatch levels, and PSH units’ operating modes. The column-and-constraint generation decomposition algorithm is applied to solve the two-stage adaptive robust optimization problem, which has a mixed-integer optimization in the inner-level problem. The developed coordination strategy is tested on the modified IEEE 39-bus system. Numerical results demonstrate that the coordinated wind and PSH units can increase the total energy served, enhance wind power dispatchability, and reduce wind power curtailment.

With increased penetration of wind power units and plug-in electric vehicles (PEVs), their control flexibility and quick response potentially provide an alternative way to fulfil the need for rapid restoration. A two-stage restoration strategy optimisation approach is presented with the coordination of PEVs and wind power units considered. The optimisation model is to maximise the restored generation capability and minimise the fluctuation of cranking power. In the first stage, the aim is to provide reliable cranking power remotely for black start generators through coordinated dispatch of PEVs and wind power units and quadratic programming (QP) models for dispatching electric vehicle aggregators (EVAs) subject to wind power fluctuations, and for dispatching numerous PEVs within each EVA are developed. To ensure close coordination between these two dispatching procedures, bi-level programming-based hierarchical decomposition approach is used to solve the QP models in an iterative way. In the second stage, an integer linear programming model is proposed to optimise the restoration schedules through an effective transformation of the original non-linear formulation, so as to reduce the computing time and effort significantly. Finally, a case study is presented to demonstrate the effectiveness and essential features of the developed models and methods.

Twenty-five years ago, J.D. Willson was the control center manager with one of the United States's largest utilities-the Pennsylvania, New Jersey, Maryland Interconnection (PJM)-and also served as chair of the IEEE Power System Restoration Training Task Force. M.E. Long was a training manager at Pepco and chair of the IEEE Working Group on Operator Training (WGOT). PJM was a pioneer in studying ways in which utilities could interconnect their power systems to increase reliability while reducing overall costs and also led efforts to improve system operator training.

Natural disasters such as hurricanes damage power distribution systems by low probability- high impact events. Other infrastructures such as water networks will be disrupted due to their dependency on the power network. In this situation, a city or region experiences critical conditions. In this paper, a new resilience index based on social welfare concept is presented to decrease unserved loads, restore the distribution system rapidly and decrease the dependency of water network operation to power network failures. The new resilience index is optimized with effective strategies including: upgrading distribution poles, DG placement with different capacities and distribution system automation. The problem is formulated as a stochastic two-stage optimization. The first-stage decisions are the number of each resilience improvement strategy limited to a predetermined budget. Genetic algorithm is applied to solve the first stage. The objective of the second stage is maximizing the social welfare which is solved by an innovative approach. Numerical simulations are performed on the IEEE 33-bus radial distribution system and designed water network related to it. The results demonstrate the effectiveness of the proposed method.

This is a study of a combined load restoration and generator start-up procedure. The procedure is structured into three stages according to the power system status and the goal of load restoration. Moreover, for each load restoration stage, the proposed algorithm determines a load restoration sequence by considering renewable energy such as solar and wind park to achieve objective functions. The validity and performance of the proposed algorithm is demonstrated through simulations using IEEE-39 network.

Boosting the resilience of power systems is one of the core requirements of smart grid. In this paper, an integrated resilience response framework is proposed, which not only links the situational awareness with resilience enhancement, but also provides effective and efficient responses in both preventive and emergency states. The core of the proposed framework is a two-stage robust mixed-integer optimization model, whose mathematical formulation is presented in this paper as well. To solve the above model, an algorithm based on the nested column-and-constraint generation decomposition is provided, and computational efficiency improvement techniques are proposed. Preventive response in this paper considers generator re-dispatch and topology switching, while emergency response includes generator re-dispatch, topology switching and load shedding. Several numerical simulations validate the effectiveness of the proposed framework and the efficiency of the solution methodology. Key findings include the following: 1) in terms of enhancing power grid resilience, the integrated resilience response is preferable to both independent preventive response and independent emergency response; 2) the power grid resilience could be further enhanced by utilizing topology switching in the integrated resilience response.

Since failure of high- to medium-voltage (MV) transformers affect a large number of consumers, they are usually built with a redundancy to guarantee service restoration in the case of a single contingency. The redundancy can be provided by a backup transformer or by transferring the load to a neighbouring substation in case of failure. While a load transfer allows for more efficient use of transformers in normal operation, it also requires the MV network to be dimensioned with redundant transmission capability for the contingency case. In this study, the authors present their approach to determine if it is profitable in the long term to remove a backup transformer in intrinsically safe substations and handle resupply with load transfer to neighbouring substations instead. To this end, they compare the cost of the necessary network expansion to the costs of a backup transformer. They introduce an iterated local search algorithm for the calculation of emergency switching plans as well as expansion of the MV network. The methodology is applied to a large real MV network group, where reinforcing the network to allow a load transfer is cost efficient compared with the existing backup transformer in three of four substations.

Top-down power system restoration following a widespread blackout begins with energization of the backbone transmission network. All interconnected regions will be restored as a whole, which needs collaboration of multiple operators. The parallel control and integrated restoration planning issues have to be addressed. In order to conduct an efficient top-down restoration process and guarantee the operational security, a hierarchical coordination mechanism and an online decision support system-based self-healing approach are proposed. Considering the multiple decision-making problems involved, an associated bi-level optimization model is built, which integrates the planning problems of backbone reconfiguration, sub-transmission system restoration, and non-black-start units start-up. Then, a solution methodology is developed to provide online decisions based on the model. Simulation results of Shandong Power System in China show that the restoration performance is significantly improved using the proposed control approach. Additionally, the decision method is proved to be efficient enough for online applications.

Rapid restoration of power systems is vitally important following an outage; however, existing optimal objectives and models to start up all the generators may cause problems where by some generators are ramping while others are waiting shown in the calculation results. To address this problem considering the generator regulation characteristics, a variable-constrained maximum-value minimisation model is proposed in this study to describe the practical problem. By introducing the time variable t, the variable-constrained optimisation problem is converted to a constrained optimal power flow problem, which can be solved using common optimisation approaches. Applying the proposed model and method, the optimisation method is discussed considering the characteristics of generators during power system black start. Numerical results show that the algorithm is effective and can significantly reduce the restoration time. The algorithm described here is applied to the Guangdong power grid self-healing decision-making system.

The theme of shocking tales describes some unexpected power system events. It is the intention to offer ways in which power engineers can learn from these unintended events and apply lessons learned by thinking beyond the usual routinized system contingencies. Attention to standards, procedures, and training are vital to the operation of the system. System planners and engineering departments should carefully consider the addition of needed facilities that can improve the robust design and operation of the system.

This paper proposes various design procedures for computing Power System Ancillary Service Requirement Assessment Indices (PSASRAI) for a Two-Area Thermal Reheat Interconnected Power System (TATRIPS) in a restructured environment. In an interconnected power system, a sudden load perturbation in any area causes the deviation of frequencies of all the areas and also in the tie-line powers. This has to be corrected to ensure the generation and distribution of electric power companies to ensure good quality. A simple Proportional and Integral (PI) controllers have wide usages in controlling the Load Frequency Control (LFC) problems. So the design of the PI controller gains for the restructured power system are obtained using Bacterial Foraging Optimization (BFO) algorithm. From the simulation results, the PSASRAI are calculated based on the settling time and peak over shoot concept of control input deviations of each area for different possible transactions. These Indices are useful for system operator to prepare the power system restoration plans. Moreover, the LFC loop coordinated with Redox Flow Batteries (RFB) has greatly improved the dynamic response and it reduces the control input requirements and to ensure improved PSASRAI, thereby improving the system reliability.

Power system dispatchers throughout the Eastern Interconnection (EI) of the United States regularly observe unusual frequency movements during the Super Bowl championship game of American football. While these movements have not been a threat to security to date, they are large enough to warrant explanation. We have found the explanation for these frequency movements through load and frequency monitoring, together with careful observation. Two mechanisms are at work. First, television viewers defer load-producing activities during periods of high interest and then carry out these activities during periods of lower interest. Second, changes in the brightness of a televised image result in appreciable changes in the load of television sets. During the Super Bowl, there is an unusually large number of televisions all displaying the same programming and an unusually large number of television viewers whose activities are synchronized to this programming. The outstanding example of the aggregated impact of changes in television image brightness occurred following a partial power outage at the Superdome stadium during Super Bowl XLVII in New Orleans on 3 February 2013.

Many weather disasters can adversely impact the power system: thunderstorms initiating a blackout of New York City on 13 July 1977, an ice storm severely damaging the transmission system in southern Quebec in 1998, and countless hurricanes and tornadoes that have knocked out service to customers for weeks at a time. The reverse can also happen: the power system is capable of creating a weather disaster. This happened in southeastern Missouri in the early morning of 14 December 2005, when so much water was pumped into the upper reservoir of the Taum Sauk pump storage plant that it overflowed, resulting in a devastating flood that destroyed a house, stranded three motorists, and did significant damage in and around a state park. Luckily, no one was killed, and most of the water ended up in the plant's lower reservoir, which was largely able to contain the flow and prevent further damage downstream.

Reducing the power system restoration time has always been an important topic in power system research. For AC/DC hybrid systems, if the rapid regulation ability of HVDC is utilized in the early stage of black start, the restoration time can be reduced. This paper proposes a HVDC startup strategy while considering HVDC lines and explores their control flexibility in the black start process. The requirement on the minimum short-circuit ratio (SCR) is presented based on the concept of critical short-circuit ratio (CSCR) under non-rated state. The maximum transmittable power of HVDC is obtained using the short-circuit ratio of the system. The feasibility of the proposed HVDC startup strategy is proved through numerical simulation on the IEEE 24-bus test system and the black-start scheme that including HVDC startup can significantly reduce the system restoration time.

Electricity outages and large scale blackouts due to natural disasters have been observed commonplace recently. Therefore, it is urgently needed to develop an efficient restoration strategy to ameliorate a grid-scale capability for restoration. With increasing penetration of renewable energy resources, it is a great potential to include wind power into the system restoration planing processes. This paper develops an efficient restoration strategy considering wind energy participation to achieve an enhanced grid resilience in response to widespread emergencies. The proposed strategy is formulated as a mixed-integer linear programming (MILP) model. In order to verify the applicability of the proposed method, the vulnerability of power elements is taken into account following a high-impact low-probability (HILP) event. The developed strategy is comprehensively tested on the modified IEEE 118-bus test system and the numerical results illustrate the efficiency of the proposed method.

The increasing wind power penetration makes it necessary for wind power to participate in system restoration, while the maturing wind power control technology makes it possible. To characterise the security level of the system accommodating a certain amount of wind power during black start, the security margin evaluation indexes of wind power particpating in black start were put forward, based on the influence of wind power on the system recovery. Then, the law of wind speed prediction error was analysed, the representative sample set of future wind conditions was generated by historical simulation method, the worst future wind conditions were obtained at a certain level of confidence, and the solution method of the security margin based on time-domain simulation was given. Additionally, with a specific black-start scheme, general steps to solve the security margin were demonstrated, the ‘wind power integration capacity – security margin’ curves were obtained, and the influence of wind power on system restoration security was analysed from multi-views. At last, the impact of wind speed prediction accuracy on system security margin was explored, and other applications of the presented method were given.

a quasi-dynamic tool suitable for validation of power system restoration (PSR) strategies at distribution level is proposed. The tool contains detailed models of loads and renewable energy source (RES)-based generation units from normal to PSR conditions. The models are utilized as back-ends of static and dynamic calculation modules. The static calculation module aims to run power flow calculation periodically in time intervals of a few seconds, while in the meantime, the dynamic module calculates the dynamic network frequency with a few millisecond resolution. The tool is capable of investigating the frequency stability degree of any Build-Up PSR strategy at distribution level (but not limited to that) both statically and dynamically in reasonable computation time.

Power system restoration has attracted more attention and made great progress recently. Research progress of the power system restoration from 2006 to 2016 is reviewed in this paper, including black-start, network reconfiguration and load restoration. Some emerging methods and key techniques are also discussed in the context of the integration of variable renewable energy and development of the smart grid. There is a long way to go to achieve automatic self-healing in bulk power systems because of its extreme complexity. However, rapidly developing artificial intelligence technology will eventually enable the step-by-step dynamic decision-making based on the situation awareness of supervisory control and data acquisition systems (SCADA) and wide area measurement systems (WAMS) in the near future.

Power system restoration is a complex and vital task, which can be viewed as the repeated reconnection of de-energised elements of the network in blackout to re-energise them. However, the restoration process will be delayed if an excessive standing phase angle difference (SPAD) is detected across lines, and any delay in the restoration increases its economic and social costs. This paper proposes a two-step method for reducing excessive SPAD. In contrast to conventional techniques, this new approach optimally reschedules the machines to reduce the excessive SPAD, whilst avoiding abrupt changes in power output, and uses real-time information that enables operators to perform restoration in real-time. The method is tested using the IEEE 118-bus test system, and the results demonstrate that it can quickly determine a solution that decreases excessive SPADs to values below a user-defined threshold, whilst reducing operational cost and requiring changes in the power output of machines smaller than a given percentage of the nominal power output.

Parallel restoration is an efficient way to speed up the restoration process after a wide-area outage or a complete blackout of a power system. To implement efficient parallel restoration, an appropriate network partitioning method is necessary. Given this background, a two-step network partitioning strategy for parallel power system restoration is presented. In order to minimise the restoration time of generating units, a grouping model for non-black-start units is developed first. Based on the graph theory, a power network partitioning model is presented with the objectives of minimising the number of the interconnected lines and maximising the electrical distance of the interconnected lines among different restoration subsystems. The well-established AMPL/CPLEX is employed to solve the developed optimisation models. Finally, the IEEE New England 10-unit 39-bus system and a part of Zhejiang provincial power system in China are employed to illustrate the feasibility and effectiveness of the developed models.

The applications of battery energy storage systems (BESSs) in power systems have been paid increasing attention in recent years. Apart from all the benefits that BESSs can bring to the power systems, their potential applications in assisting power system restoration after a major blackout have not yet been systematically investigated. The flexible charging and discharging characteristics of BESSs could help maintain the balance between power supply and demand during the system restoration process, thus the recovery speed of the power system concerned after a blackout could be accelerated. Given this background, the applications of BESSs in power system restoration is investigated. First, the potential applications of BESSs during power system restoration process are discussed. A multi-objective optimisation model is next proposed, aiming at minimising the number of circuit breaker operations and outage durations of both the non-black-start generating units and the important loads. Meanwhile, the application of intermittent renewable energy sources for improving power system restoration is also discussed. The operation strategy of BESSs will also be optimised after the system restoration scheme is attained through the multi-objective optimisation. The proposed method is demonstrated by numerical tests on the IEEE 30-bus and 162-bus test systems.

Operator Training Simulators (OTS) have proven as a most useful restoration-training tool since years as they provide an utmost realistic control centre atmosphere and environment. With the change of the industry from a pure technically driven system towards a market dominated system new challenges in power system operation occur for control centre operators. To perform adequate and efficient training an OTS underlies these changes in various aspects especially with regard to data and information storage and handling as well as to modeling components required. The paper describes the ongoing development of an Operational training system, which development started at a University as a prototype and is nowadays operated by DUtrain - an independent training centre - used in well-designed operator training programs.

This work was conducted in part at NICTA and is funded by the Australian Government through the Department of Communications and the Australian Research Council through the ICT Centre of Excellence Program.

Power system restoration (PSR) is a very important procedure to ensure the consumer supply. In this paper, a decentralized multi-agent system (MAS) for dealing with the microgrid restoration procedure is proposed. In this method, each agent is associated with a consumer or microsource (MS) and these communicate with each other to reach a common decision. The agents solve a 0/1 knapsack problem to determine the best load connection sequence during the microgrid restoration procedure and then the proposed MAS is tested in one specific scenario where the microgrid is subjected to a blackout that occurred. This means that all the resources and loads are disconnected. This work is developed in Matlab/Simulink environment and the results show its feasibility and effectiveness in the microgrid restoration procedure.

This paper proposes a multi-agent approach to power system restoration. So far, numerous studies have been conducted on power system restoration problems. From the view point of the system structures, these researches can be divided into two categories: centralized systems and decentralized systems. In this study, we have solved the distribution power system restoration problem by using multi-agent approach, which is categorized in the distributed approach. The solved solutions have been compared with the solutions which were solved by the mathematical programming approach. From the simulation results, it can be seen the proposed restoration method could reach the right solution by making use of only local information. The solution quality is equivalent to the quality of the centralized system. This means that the proposed multi-agent restoration system is a promising approach to more large-scale distribution network.

Outages and faults cause problems in interconnected power system with huge economic consequences in modern societies. In the power system blackouts, black start resources such as micro combined heat and power (CHP) systems and renewable energies, due to their self-start ability, are one of the solutions to restore power system as quickly as possible. In this paper, we propose a model for power system restoration considering CHP systems and renewable energy sources as being available in blackout states. We define a control variable representing a level of balance between the distance and importance of loads according to the importance and urgency of the affected customer. Dynamic power flow is considered in order to find feasible sequence and combination of loads for load restoration.

Traditional and current restoration strategies use top- down approach that rely on the use of centralised conventional generation such as hydropower plants and gas power plants to start up the network after a wide area blackout. Analysis of restoration steps is also based on AC networks with no involvement of DC schemes. The distribution network has also been assumed to be passive having to wait for the transmission scheme to be stable. Today and future restoration strategies should align with the changing network paradigm. Prediction of high penetration of renewable resources coupled with increasing DC schemes demands change in restoration strategies. A review of role of Wind Power Plants, HVDC, BESS, SST and WAMS in the restoration process is presented in this paper.

Fast restoration of critical loads and non-black-start generators can significantly reduce the economic losses caused by power system blackouts. In a parallel power system restoration scenario, the sectionalization of restoration subsystems plays a very important role in determining the pickup of critical loads before synchronization. Most existing research mainly focuses on the startup of non-black-start generators. The restoration of critical loads, especially the loads with cold load characteristics, has not yet been addressed in optimizing the subsystem divisions. As a result, sectionalized restoration subsystems cannot achieve the best coordination between the pickup of loads and the ramping of generators. In order to generate sectionalizing strategies considering the pickup of critical loads in parallel power system restoration scenarios, an optimization model considering power system constraints, the characteristics of the cold load pickup and the features of generator startup is proposed in this paper. A bi-level programming approach is employed to solve the proposed sectionalizing model. In the upper level the optimal sectionalizing problem for the restoration subsystems is addressed, while in the lower level the objective is to minimize the outage durations of critical loads. The proposed sectionalizing model has been validated by the New-England 39-bus system and the IEEE 118-bus system. Further comparisons with some existing methods are carried out as well.

The network reconfiguration is an important stage of restoring a power system after a complete blackout or a local outage. Reasonable planning of the network reconfiguration procedure is essential for rapidly restoring the power system concerned. An approach for evaluating the importance of a line is first proposed based on the line contraction concept. Then, the interpretative structural modeling (ISM) is employed to analyze the relationship among the factors having impacts on the network reconfiguration. The security and speediness of restoring generating units are considered with priority, and a method is next proposed to select the generating unit to be restored by maximizing the restoration benefit with both the generation capacity of the restored generating unit and the importance of the line in the restoration path considered. Both the start-up sequence of generating units and the related restoration paths are optimized together in the proposed method, and in this way the shortcomings of separately solving these two issues in the existing methods are avoided. Finally, the New England 10-unit 39-bus power system and the Guangdong power system in South China are employed to demonstrate the basic features of the proposed method.

The Distributed Generator (DG) based intentional islanding is very useful and improves the stability of power system. But the inverter based connection of DG leads to power quality related issues like harmonics injunction, voltage flicker and non-sine wave output. As a remedy, modeling and control of fuel cell based distribution generation system is studied and implemented for Thermal Power Station (TPS) for improving power system reliability. The TPS auxiliaries which are receiving power from station transformer during healthy system conditions, stop functioning during faulty grid conditions as it is difficult to fulfill their power demand. The paper proposes a novel method for running TPS auxiliaries during system disturbance using fuel cell as an alternative source of power. The voltage profile in the proposed method is maintained using power flow controller (PFC). The multi converter power flow controller is used for easy power and voltage profile control. It is observed that separate use of fuel cell as a DG and Generalized Unified Power Flow Controller (GUPFC) as a PFC fail to show desired results. The proposed method is studied and simulated with standard IEEE and real time test systems. It is observed that using proposed method uninterrupted working of TPS auxiliaries is possible during condition of system disturbance. This unaffected TPS system is identified as a source of power during system restoration which is followed by grid disturbance.

Multi agent system (MAS) is one of the most dominant research wings which consist of several agents who interact with each other to achieve a common objective. MAS has been developed for a wide range of applications in power systems. Power system restoration is a main application of that. Researchers present several architectures for fault identification, isolation and restoration of the power system. This paper presents a complete literature review on available architectures for power distribution restoration and future trends in MAS based power system restoration.

The fast network restoration is required to restore the Shipboard power system (SPS) to near pre-fault condition for proper functioning. This paper proposed an improved Particle Swarm Optimization for restoration of shipboard power system. Firstly, we proposed an improvement strategy of S-Curve Decreasing Inertia Weight. Secondly, the feedback mechanism was introduced to improve the algorithm rate of convergence. Particle swarm optimization algorithm enables to find the optimal combination of loads that can be supplied after the occurrence of the fault, considering the priorities of the loads and the constraint of balance between the total load and total generation. The proposed method is applied to a naval shipboard power system model.

The residual load power gradients over high-voltage-medium-voltage (HV-MV) power transformers after re-energization of long-lasting interrupted MV-grids are investigated. In this paper, the MV-grids are assumed to serve only residential areas with high thermal load capacities whose diversity factors are significantly influenced by power interruption durations causing the cold load pick-up (CLPU) phenomenon. Increasing shares of volatile renewable energy source (RES) generation with automatic-synchronization characteristics in MV-grids and their underlying grids influence the abovementioned residual load gradients. This paper investigates possible ways of regulating the residual load gradients especially for the frequency-sensitive HV-grid islands to reach a successful power system restoration.

Intentional Controlled Islanding (ICI) can prevent blackouts by splitting the system into islands following a severe disturbance. Post-islanding events, however, might lead to instabilities that can result into blackouts within one or more islands. Although it is critical to ensure that the islands can be restored in the case of local blackouts, this has not been addressed in the literature. To fill this gap, this paper proposes an ICI method that considers not only the typical ICI constraints, but also Parallel Power System Restoration (PPSR) constraints. The traditional islanding problem for minimal power-flow disruption ensuring the typical generator coherency constraint is extended to include at least one blackstart unit within each island and to exclude various branches from possible solutions. To understand the extent to which each island can be restored, the method quantifies the active and reactive power generation available within each island to determine the maximum load that can be picked up. By applying the proposed ICI method, the restoration process can be facilitated and speeded up. Simulation studies on two IEEE test systems are used to demonstrate the effectiveness of the method in determining an islanding solution that considers PPSR constraints with different network topologies and sizes. Las islas controladas intencionales (ICI, siglas en inglés) pueden evitar apagones de gran extensión mediante la división del sistema eléctrico en islas después de una perturbación severa. No obstante, eventos posteriores a la creación de estas islas podrían conducir a inestabilidades que pueden resultar en apagones dentro de una o más islas. Por lo tanto, garantizar que estas se puedan restaurar en el caso de apagones locales es fundamental, sin embargo, esto no se ha abordado en la literatura. Para llenar este vacío, este artículo propone un método de ICI que considera junto a sus restricciones típicas, la restauración en paralelo del sistema de potencia (PPSR, siglas en inglés). Se considera la mínima interrupción del flujo de potencia garantizando la coherencia de generadores, pero se amplía para incluir al menos una unidad de arranque autógeno dentro de cada isla y para excluir distintas líneas de las posibles soluciones. El método cuantifica la generación de energía activa y reactiva disponible dentro de cada isla para determinar la máxima demanda que puede ser incrementada. Utilizando el método propuesto, el proceso derestauración puede facilitarse y acelerarse. Para demostrar la eficacia del método propuesto en la determinación de una solución de islas considerando PPSR, fueron realizadas simulaciones en dos sistemas de la IEEE con diferentes topologías y tamaños.