Power System Restoration Plans Research Articles

Survey of Power System Restoration Documents Issued from 2016 to 2021

More than thirty-six partial or whole blackouts, from 2016 to 2021, prove that neither the probability of blackouts can be ignored nor the required plans and the readiness of the utilities for power system restoration can be forgotten. To properly deal with blackouts and minimize the social and economic costs, utilities should prepare a suitable restoration plan in advance to quickly restore the system to the normal state and minimize the restoration time and loss of energy. In this paper, after summarizing major blackouts occurred from 2016 to 2021, the progress in the research reports, industrial documents, and books in the context of power system restoration is reviewed to show and classify the different aspects of power system restoration plans and strategies presented during these years. This review indicates that although there are many published methods and techniques which have tried to give more autonomous solutions, there are still more complexities in power system restoration. However, this paper respects all efforts and attempts and tries to illustrate the achievements, up to now, in power system restoration, as well as research gaps.

The Importance of Power Generation Plants with Blackstart on Power System Restoration after Blackout

Güç sistemleri, elektrik enerjisinin kesintisiz bir şekilde tüketiciye ulaştırılmasını sağlayan ve birbiriyle koordineli çalıştırılan ekipmanların toplamı şeklinde ifade edilen kompleks yapılardır. Ancak bazı durumlarda güç sisteminde tam ya da kısmi olarak sistem çökmesi meydana gelebilmektedir. Bu sistem çökmesi bazen hemen giderilebilirken bazen de giderilmesi uzun sürmektedir. Uzun süren kesintiler sonrasında toplumsal yaşam, gündelik faaliyetler ve üretim faaliyetleri sekteye uğramakta; bu durum maddi olarak büyük bir kayba yol açmaktadır. Güç sisteminin tamamında meydana gelen bir sistem çökmesi sonrasında özenilerek hazırlanmış olan güç sistem restorasyonu planları hemen uygulanmaya başlanmalıdır. Güç sisteminin restorasyonunda kritik bir rol oynayan yeniden toparlanma özellikli güç üretim ünitelerinin konumu ve kapasitesi, sistem çökmesi sonrasında uygulanacak olan restorasyon stratejisine karar vermede büyük bir öneme sahiptir. Yapılan bu çalışmada güç sisteminin tam çökmesi sonrasında yeniden toparlanma özellikli güç üretim santrallerinin sistem restorasyonunda önemini anlamak için gerçek veriler kullanılarak simülasyon çalışması yapılmıştır. Yapılan çalışmada sistem çökmesi ve sistem restorasyonunun uygulama safhalarında güç üretim birimlerinin davranışları incelenmiştir. Güç sistem restorasyon planları hazırlanırken dikkat edilmesi gereken hususlar ile ilgili bilgi verilmiştir.

Advanced extended-term simulation approach with flexible quasisteady-state and dynamic semi-analytical simulation engines

Power system simulations that extend over a time period of minutes, hours, or even longer are called extended-term simulations. As power systems evolve into complex systems with increasing interdependencies and richer dynamic behaviors across a wide range of timescales, extended-term simulation is needed for many power system analysis tasks (e.g., resilience analysis, renewable energy integration, cascading failures), and there is an urgent need for efficient and robust extended-term simulation approaches. The conventional approaches are insufficient for dealing with the extended-term simulation of multi-timescale processes. This paper proposes an extended-term simulation approach based on the semi-analytical simulation (SAS) methodology. Its accuracy and computational efficiency are backed by SAS's high accuracy in event-driven simulation, larger and adaptive time steps, and flexible switching between full-dynamic and quasi-steady-state (QSS) models. We used this proposed extended-term simulation approach to evaluate bulk power system restoration plans, and it demonstrates satisfactory accuracy and efficiency in this complex simulation task.

Power System Restoration Using Multilayer Perceptron

In recent years, power systems are being operated nearer to their limits due to economic competition and deregulation. Also, nowadays the challenge is to include large and ever increasing amounts of decentralized generated power into the existing transmission network and at the same time comply with the electricity market transmission demands. Both factors increase the risk of blackout. After which, power needs to be restored as quickly and reliably as possible and, accordingly, detailed power system restoration plans are required. The multilayer perceptron network is chosen for a more precise examination.

A comprehensive literature review report on basic issues of power system restoration planning

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.

Electrical power system restoration planning in southern area of Lao PDR

Electrical power system restoration planning in southern area of Lao PDR

Power System Restoration Planning Strategy Based on Optimal Energizing Time of Sectionalizing Islands

Common power system restoration planning strategy is based on a ‘build up’ approach, where a blackout system is sectionalized among several islands for parallel restoration prior to resynchronization. In order to speed up the resynchronization of the islands, each island must have similar energizing times. However, there is a huge number of possible combinations of islands that can be formed. Thus, this paper proposes a method to determine optimal islands that have similar energizing times. The method involves identifying transmission lines that should not be connected to form the islands. The proposed method is based on the combination of heuristic and discrete optimization methods. The heuristic technique is proposed to find initial solution that is close to the optimal solution. This solution will guide the optimization technique, which is the discrete Artificial Bee Colony optimization method, to find the optimum solution. The proposed method also considers restoration constraints including black start generator availability, load-generation balance, and the maintenance of acceptable voltage magnitude within each island. The proposed method is validated via simulation using IEEE 39, 118-bus and 89-bus European systems. The advantage of the proposed method in terms of restoration time is demonstrated through a comparison with other literature.

Parallel power system restoration planning using heuristic initialization and discrete evolutionary programming

This paper proposes a sectionalizing planning for parallel power system restoration after a complete system blackout. Parallel restoration is conducted in order to reduce the total restoration process time. Physical and operation knowledge of the system, operating personnel experience, and computer simulation are combined in this planning to improve the system restoration and serve as a guidance for system operators/planners. Sectionalizing planning is obtained using discrete evolutionary programming optimization method assisted by heuristic initialization and graph theory approach. Set of transmission lines that should not be restored during parallel restoration process (cut set) is determined in order to sectionalize the system into subsystems or islands. Each island with almost similar restoration time is set as an objective function so as to speed up the resynchronization of the islands. Restoration operation and constraints (black start generator availability, load-generation balance and maintaining acceptable voltage magnitude within each island) is also taken into account in the course of this planning. The method is validated using the IEEE 39-bus and 118-bus system. Promising results in terms of restoration time was compared to other methods reported in the literature.

An Integrated Approach for Power System Restoration Planning

Power system outages/blackouts, especially weather related, are becoming more and more frequent, incurring significant economic and social costs. The ability to restore power services quickly after a blackout is crucial for power system resilience. Power system restoration is an extremely complicated process, involving multiple steps, highly combinatorial operational decisions, and highly nonlinear technical constraints, which make restoration planning an exceptionally challenging task. This paper will first introduce the restoration process and operations, examine important issues in restoration, and survey the state of the art in the research and practice of power system restoration planning. Then, we will focus on the commonly used buildup restoration planning strategy, in which the system is sectionalized into smaller subsystems with initial power sources, and then the subsystems are restored in parallel. Due to the complexity, existing approaches treat the sectionalization and restoration separately, leading to a suboptimal restoration plan. We will introduce an integrated restoration planning approach to improve the quality of restoration plans globally (such as shorter overall restoration time) by using mathematical programming and simulation in an interactive and iterative way. Case studies will be provided to illustrate the effectiveness of the proposed approach.

Ancillary Service Requirement Assessment Indices for the Load Frequency Control in a Restructured Power System with Redox Flow Batteries

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.

PI2 controller based coordinated control with Redox Flow Battery and Unified Power Flow Controller for improved Restoration Indices in a deregulated power system

Abstract The nature of power system restoration problem involves status assessment, optimization of generation capability and load pickup. This paper proposes the evaluation of Power System Restoration Indices (PSRI) based on the Automatic Generation Control (AGC) assessment of interconnected power system in a deregulated environment. The PSRI are useful for system planners to prepare the power system restoration plans and to improve the efficiency of the physical operation of the power system with the increased transmission capacity in the network. The stabilization of frequency and tie-line power oscillations in an interconnected power system becomes challenging when implemented in the future competitive environment. This paper also deals with the concept of AGC in two-area reheat power system having coordinated control action with Redox Flow Battery (RFB) and Unified Power Flow Controller (UPFC) are capable of controlling the network performance in a very fast manner and improve power transfer limits in order to have a better restoration. In addition to that a new Proportional–Double Integral (PI2) controller is designed and implemented in AGC loop and controller parameters are optimized through Bacterial Foraging Optimization (BFO) algorithm. Simulation results reveal that the proposed PI2 controller is that it has good stability during load variations, excellent transient and dynamic responses when compared with the system comprising PI controller. Moreover the AGC loop with RFB coordinated with UPFC has greatly improved the dynamic response and it reduces the control input requirements, to ensure improved PSRI in order to provide the reduced restoration time, thereby improving the system reliability.

Judgment of Temporary over Voltages during Transformer Refurbishment

In this research work Radial Basis Function (RBF) Neural Network (NN) and Regression models are used to estimate Temporary over Voltages (TOVs) that are occurred during the reenergization of lightly loaded transformer. Assessment of the TOVs are carried out in order to control the high peak voltage up to a safe operating point to ensure the safety of the power system equipments. The proposed approaches are applied to the standard IEEE 30 bus test system to evaluate its efficacy. The statistical approach is applied to examine the robustness of the forecasting results. Results show that the methods conveyed in this research are better and could be helpful for power system restoration planning.

Permutation-based Power System Restoration in Smart Grid Considering Load Prioritization

In the smart grid environment, a power system restoration plan with flexibility is needed to improve reliability and efficiency in an automated way. Traditional system restoration methods based on fixed time intervals may not meet the requirement. This article proposes a new permutation-based model for power system restoration within an optimized flexible duration considering available generator capability and load prioritization. By utilizing this new model, power system restoration is formulated as a permutation-based combinatorial optimization problem to maximize the restored load per unit time. Finally an action-by-action flexible time schedule is obtained for generator startup. A novel quantum-inspired evolutionary algorithm, called the quantum-inspired differential evolutionary algorithm, has been applied to solve this problem due its to high population diversity and fast convergence. The effectiveness of the proposed restoration approach has been validated using IEEE 39- and 57-bus systems.

Use of HVDC links for power system restoration

Power system restoration plans worldwide have often been based on black start units capable of supplying cranking power to bulk generation plants. The increase in the number and size of CCGT plants and other forms of generation with low regulating capacity and requiring a restless growing power for the cranking phase needs that new strategies and tools be developed for facing the unlucky event of a black-out. The study presents the possibility of using HVDC links with a synchronous compensator at the receiving end. Such systems have high regulating capacity and reliability which are precious characteristics during the critical phases of the restoration. A detailed stability analysis is developed for checking the correct size of the compensator. Electromagnetic simulations prove the validity of the solution.

Power system restoration plan using the characteristics of scale‐free networks

AbstractA reliable electricity supply infrastructure is fundamental to modern living. An interruption to electricity services has such far reaching impact to our everyday lives to various industries compared to other service interruptions, thus to build in significant redundancy and various preventive measures to electric power system operation and planning is needed. Just as important as to incorporate redundancy and preventive measures however, an effective restoration plan needs to be in place since the possibility of electricity service interruption cannot be eliminated completely.In this paper, a novel power system restoration plan that utilizes the characteristic of so‐called scale‐free networks is proposed. For a scale‐free network, the importance of each node is determined based on the number of connections made to other nodes in that the nodes with many connections, thus important, are called “hubs.” A scale‐free network is a special complex network which follows a power law distribution, that is few hubs and many nodes with few connections at various system sizes. In the proposed plan the hubs are restored before other insignificant nodes in the system. It is shown that by doing so, the total restoration time can be reduced considerably, and notable improvements can be achieved with respect to the objective function in the mathematical formulation of electric power system restoration problem with a few constraints introduced in this paper. The effectiveness of proposed plan is tested with one of the planning problems such as valuation of black‐start capable generators using IEEE‐30 bus system. Copyright © 2008 John Wiley & Sons, Ltd.

Visualization of Power System Restoration Plans Using CPM/PERT Graphs

The risk of blackouts is inherent in complex power systems, despite all efforts to prevent their occurrences. To mitigate the consequences of major blackouts, better restoration plans have been demanded. Commonly, these plans consist of a set of actions textually described. In order to enhance the operating staff comprehension about the restoration plan, this paper proposes a methodology, based on CPM/PERT graph theory, that allows power system restoration plans to be graphically visualized. This approach permits to clearly see the precedence relations among activities and to graphically follow the restoration process during its execution. The methodology can also take advantage of calculations involved with CPM/PERT methods to evaluate the restoration duration and the plan critical path. The application of the proposed approach is illustrated using the IEEE 30-bus network and the restoration plan developed for a portion of the Brazilian interconnected power system.

Modelagem de planos de recomposição de sistemas elétricos como grafos CPM/PERT

Esse trabalho formaliza um modelo de grafos CPM/PERT para viabilizar a representação de planos de recomposição de sistemas elétricos e expõe uma metodologia para derivação automática do mesmo a partir da lista de atividades de um procedimento de recomposição. Essa técnica de montagem automática foi aplicada com sucesso a uma instrução operativa de recomposição pós-blecautes do sistema interligado nacional (SIN), referente a uma porção da rede elétrica do sul do Brasil, que compreende as usinas hidrelétricas de Capivara e Taquaruçu, o corredor de transmissão associado a essas usinas e as subestações de Assis e Londrina.

Interactive long-term simulation for power system restoration planning

The problem of restoring a power system following a complete blackout is complex and multi-faceted, Many control actions have to be performed on time, while constraints such as power balance and system stability have to be carefully respected, In this paper, the application of long-term dynamic analysis in studying frequency and voltage responses due to load and generation mismatches in isolated systems or during extension of the existing system in the restoration phase is presented. Simulation results covering the main steps of the Hellenic power system restoration process following a recent total blackout are presented and discussed.

A systematic method for power system restoration planning

This paper describes a systematic method for power system restoration planning. System restoration at Hydro-Quebec is performed according to a set of detailed emergency instructions. The basis for these instructions is a restoration plan that is prepared off-line by operation planners. This plan includes a switching scenario with a set of values for the control variables-generator voltages, shunt reactors and load levels-that satisfy the operating constraints. Finding a suitable set of control variables usually requires many load-flow runs in a trial-and-error process. However, the problem can be formulated as a nonlinear optimization problem. The optimization algorithm which solves that problem provides values for the control variables automatically. This algorithm is linked to a user interface which constitutes a powerful tool for system restoration planning. >

Power system restoration planning

Power system restoration, as an extraordinary mode of system operation, requires careful planning and operator training. The generic tasks of restoration include determination of system and equipment status, preparation of plants and network for systematic restoration, reenergization of the network, and system rebuilding. The procedures for developing an effective restoration plan include formation of a qualified planning team, review of relevant system characteristics, formulation of assumptions regarding blackout scenarios, agreement on restoration goals, development of strategy and tactics, validation of the plan, training, and documentation. >