scholarly journals Adaptive Control for Energy Exchange with Probabilistic Interval Predictors in Isolated Microgrids

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 375 ◽  
Author(s):  
Jiayu Cheng ◽  
Dongliang Duan ◽  
Xiang Cheng ◽  
Liuqing Yang ◽  
Shuguang Cui
Keyword(s):  
Energy Exchange ◽  
Programming Model ◽  
System Stability ◽  
System Capacity ◽  
Mixed Integer ◽  
Sufficient Information ◽  
Exchange Method ◽  
Optimal Dispatch ◽  
Optimization Stage ◽  
The Stability

Stability and reliability are of the most important concern for isolated microgrid systems that have no support from the utility grid. Interval predictions are often applied to ensure the system stability of isolated microgrids as they cover more uncertainties and robust control can be achieved based on more sufficient information. In this paper, we propose a probabilistic microgrid energy exchange method based on the Model Predictive Control (MPC) approach to make better use of the prediction intervals so that the system stability and cost efficiency of isolated microgrids are improved simultaneously. Appropriate scenarios are selected from the predictions according to the evaluation of future trends and system capacity. In the meantime, a two-stage adaptive reserve strategy is adopted to further utilize the potential of interval predictions and maintain the system security adaptively. Reserves are determined at the optimization stage to prepare some extra capacity for the fluctuations in the renewable generation and load demand at the operation stage based on the aggressive and conservative level of the system, which is automatically updated at each step. The optimal dispatch problem is finally formulated using the mixed-integer linear programming model and the MPC is formulated as an optimization problem with a discount factor introduced to adjust the weights. Case studies show that the proposed method could effectively guarantee the stability of the system and improve economic performance.

scholarly journals Analysis of transport system stability

2021 ◽  
Vol 326 ◽  
pp. 00028
Author(s):  
Svetlana Borodulina ◽  
Ekaterina Tabachnikova
Keyword(s):  
Transport System ◽  
Road Transport ◽  
Transport Infrastructure ◽  
System Stability ◽  
System Capacity ◽  
Transport Systems ◽  
Transport Sector ◽  
Regional Transport ◽  
The Stability ◽  
Definition Of

The article considers the description of the internal sustainability of regional road transport systems through parameters that reflect potential and realised opportunities in regional freight transport operations. There is the author’s vision of the regional road transport system for the transport of goods by road as a target-oriented set of elements, including vehicles, transport infrastructure, technical devices, equipment, and employees, organisational structures that ensure the achievement of management objectives in the transport sector of the region. They conclude that an important element in the management of the functioning and developing road transport in the region is considering the factors that determine the internal sustainability of the system. The paper provides the author’s definition of the internal sustainability potential of the regional road transport system. It proposes an approach to assess the internal sustainability of regional road transport systems based on the elements of regional transport system capacity, such as infrastructure capacity, operational capacity and freight demand capacity in the region. Researchers developed a system of indicators to assess each capacity element from the perspective of the internal sustainability of the system. The article focuses on the study of system stability based on the assessment of deviations from equilibrium states that ensure the stability of the system within its baseline parameters and characteristics, and its adaptability to deviations from the baseline values. It uses regional statistics to assess the internal sustainability of regional road transport systems and describes their internal instability factors. The authors present a visualisation of a model for assessing the internal sustainability of a regional transport system.

scholarly journals Integrated Energy System Configuration Optimization for Multi-Zone Heat-Supply Network Interaction

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3052 ◽  
Author(s):  
Tang Bo ◽  
Gao Gangfeng ◽  
Xia Xiangwu ◽  
Yang Xiu
Keyword(s):  
Programming Model ◽  
Clean Energy ◽  
Energy System ◽  
Collaborative Optimization ◽  
Energy Utilization ◽  
System Capacity ◽  
Mixed Integer ◽  
Heat Network ◽  
Network Interaction ◽  
Integrated Energy System

The integrated energy system effectively improves the comprehensive utilization of energy through cascade utilization and coordinated scheduling of various types of energy. Based on the independent integrated energy system, the thermal network interaction between different load characteristic regions is introduced, requiring a minimum thermal grid construction cost, CCHP investment operation cost and carbon emission tax as the comprehensive optimization targets, and making overall optimization to the configuration and operation of the multi-region integrated energy systems. This paper focuses on the planning of equipment capacity of multi-region integrated energy system based on a CCHP system and heat network. Combined with the above comprehensive target and heat network model, a mixed integer linear programming model for a multi-region CCHP system capacity collaborative optimization configuration is established. The integrated energy system, just a numerical model solved with the LINGO software, is presented. Taking a typical urban area in Shanghai as an example, the simulation results show that the integrated energy system with multi-zone heat-suply network interaction compared to the single area CCHP model improved the clean energy utilization of the system, rationally allocates equipment capacity, promotes the local consumption of distributed energy, and provides better overall system benefits.

Analysis on the Penetration Level of Wind Farm Considering Transient Stability Constraint and Uncertainty of Wind Power

2020 ◽  
Vol 13 (7) ◽  
pp. 1078-1086
Author(s):  
Bai Hao ◽  
Huang Andi ◽  
Zhou Changcheng
Keyword(s):  
Wind Power ◽  
Energy Function ◽  
Wind Farm ◽  
Transient Stability ◽  
Programming Model ◽  
Forecast Error ◽  
Credibility Theory ◽  
Mixed Integer ◽  
Stability Constraint ◽  
Level Problem

Background: The penetration level of a wind farm with transient stability constraint and static security constraint has been a key problem in wind power applications. Objective: The study explores maximum penetration level problem of wind considering transient stability constraint and uncertainty of wind power out, based on credibility theory and corrected energy function method. Methods: According to the corrected energy function, the transient stability constraint of the power grid is transferred to the penetration level problem of a wind farm. Wind speed forecast error is handled as a fuzzy variable to express the uncertainty of wind farm output. Then this paper builds a fuzzy chance-constrained model to calculate wind farm penetration level. To avoid inefficient fuzzy simulation, the model is simplified to a mixed integer linear programming model. Results: The results validate the proposed model and investigate the influence of grid-connection node, wind turbine characteristic, fuzzy reliability index, and transient stability index on wind farm penetration level. Conclusion: The result shows that the model proposed in this study can consider the uncertainty of wind power out and establish a quantitative transient stability constraint to determine the wind farm penetration level with a certain fuzzy confidence level.

scholarly journals Optimal Placement and Sizing of D-STATCOM in Radial and Meshed Distribution Networks Using a Discrete-Continuous Version of the Genetic Algorithm

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1452
Author(s):  
Cristian Mateo Castiblanco-Pérez ◽  
David Esteban Toro-Rodríguez ◽  
Oscar Danilo Montoya ◽  
Diego Armando Giral-Ramírez
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Programming Model ◽  
Distribution Networks ◽  
Optimization Method ◽  
Optimal Placement ◽  
Mixed Integer ◽  
Power Balance ◽  
Continuous Version ◽  
Discrete Part

In this paper, we propose a new discrete-continuous codification of the Chu–Beasley genetic algorithm to address the optimal placement and sizing problem of the distribution static compensators (D-STATCOM) in electrical distribution grids. The discrete part of the codification determines the nodes where D-STATCOM will be installed. The continuous part of the codification regulates their sizes. The objective function considered in this study is the minimization of the annual operative costs regarding energy losses and installation investments in D-STATCOM. This objective function is subject to the classical power balance constraints and devices’ capabilities. The proposed discrete-continuous version of the genetic algorithm solves the mixed-integer non-linear programming model that the classical power balance generates. Numerical validations in the 33 test feeder with radial and meshed configurations show that the proposed approach effectively minimizes the annual operating costs of the grid. In addition, the GAMS software compares the results of the proposed optimization method, which allows demonstrating its efficiency and robustness.

scholarly journals New general mixed-integer linear programming model for mobile workforce management

2021 ◽  
Author(s):  
András Éles ◽  
István Heckl ◽  
Heriberto Cabezas
Keyword(s):  
Programming Model ◽  
Time Windows ◽  
Mutual Exclusion ◽  
Parallel Execution ◽  
Mixed Integer ◽  
Management Problem ◽  
Routing Problem ◽  
Workforce Management ◽  
Computational Performance ◽  
Wide Range

AbstractA mathematical model is introduced to solve a mobile workforce management problem. In such a problem there are a number of tasks to be executed at different locations by various teams. For example, when an electricity utility company has to deal with planned system upgrades and damages caused by storms. The aim is to determine the schedule of the teams in such a way that the overall cost is minimal. The mobile workforce management problem involves scheduling. The following questions should be answered: when to perform a task, how to route vehicles—the vehicle routing problem—and the order the sites should be visited and by which teams. These problems are already complex in themselves. This paper proposes an integrated mathematical programming model formulation, which, by the assignment of its binary variables, can be easily included in heuristic algorithmic frameworks. In the problem specification, a wide range of parameters can be set. This includes absolute and expected time windows for tasks, packing and unpacking in case of team movement, resource utilization, relations between tasks such as precedence, mutual exclusion or parallel execution, and team-dependent travelling and execution times and costs. To make the model able to solve larger problems, an algorithmic framework is also implemented which can be used to find heuristic solutions in acceptable time. This latter solution method can be used as an alternative. Computational performance is examined through a series of test cases in which the most important factors are scaled.

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