scholarly journals A Practical Formulation for Ex-Ante Scheduling of Energy and Reserve in Renewable-Dominated Power Systems: Case Study of the Iberian Peninsula

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1939 ◽  
Author(s):  
Miguel Carrión ◽  
Rafael Zárate-Miñano ◽  
Ruth Domínguez
Keyword(s):  
Stochastic Programming ◽  
Power Systems ◽  
Power System ◽  
Iberian Peninsula ◽  
Ad Hoc ◽  
Computational Time ◽  
Operational Practices ◽  
Mathematical Programming Problems ◽  
Time Required

Scheduling energy and reserve in power systems with a large number of intermittent units is a challenging problem. Traditionally, the reserve requirements are assigned after clearing the day-ahead energy market using ad hoc rules or solving computationally intense mathematical programming problems to co-optimize energy and reserve. While the former approach often leads to costly oversized reserve provisions, the computational time required by the latter makes it generally incompatible with the daily power system operational practices. This paper proposes an alternative deterministic formulation for computing the energy and reserve scheduling, considering the uncertainty of the demand and the intermittent power production in such a way that the resulting problem requires a lower number of constraints and variables than stochastic programming-based formulations. The performance of the proposed formulation has been compared with respect to two standard stochastic programming formulations in a small-size power system. Finally, a realistic case study based on the Iberian Peninsula power system has been solved and discussed.

A study of a rover wheel for Martian explorations, based on a flexible multibody approach

2019 ◽  
Vol 234 (2) ◽  
pp. 306-321 ◽  
Author(s):  
Stefano Sivo ◽  
Angelo Stio ◽  
Francesco Mocera ◽  
Aurelio Somà
Keyword(s):  
Ad Hoc ◽  
General Purpose ◽  
Design Stage ◽  
Computational Time ◽  
Multibody Model ◽  
Modelling Strategies ◽  
Pros And Cons ◽  
Time Required ◽  
Solution Accuracy

Vehicles for planetary exploration have to operate in completely different environments from Earth. For this reason, the design process of the exploration unit has an important role and can affect the requirements of the entire mission for the different space agencies involved. These operations are very expensive and time consuming, so that, over the years, ad hoc CAE methods have been developed to help engineers in the design stage. These methods are used to simulate several working conditions, evaluating which manoeuvres robots can safely perform during their mission. In this framework, a study was performed by Politecnico di Torino and Thales Alenia Space Italia. The goal was to find an efficient way to implement flexibility properties of a special wheel of a Rover for Martian explorations in a commercial (general purpose) MTB code. The ExoMars Rover was considered as case study of this work. When dealing with manoeuvres feasibility analysis, the best compromise between solution accuracy and computational time required must be found. The aim of this study was to explore pros and cons of several techniques which could allow modelling a complex flexible wheel using a commercial general-purpose MTB code. The absolute nodal coordinate formulation was compared with the other reduced-order modelling strategies proposed by the authors to implement the flexibility of a wheel in a multibody model of the full vehicle. Numerical results show good performance of the reduced morphing model in terms of computational time versus numerical accuracy.

scholarly journals Voltage Coordination via Communication in Large-Scale Multi-Area Power Systems. Part I: Principal

2012 ◽  
Vol 433-440 ◽  
pp. 7175-7182
Author(s):  
Mohammad Moradzadeh ◽  
René Boel
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electricity Market ◽  
Large Scale ◽  
Electric Power Systems ◽  
Coordination Control ◽  
Coordination Problem ◽  
Control Actions ◽  
System Operator

This two-part paper deals with the coordination of the control actions in a network of many interacting components, where each component is controlled by independent control agents. As a case study we consider voltage control in large electric power systems, where ever-increasing pressures from the liberalization and globalization of the electricity market has led to partitioning the power system into multiple areas each operated by an independent Transmission System Operator (TSO). Coordination of local control actions taken by those TSOs is a very challenging problem as poorly coordinated operation of TSOs may endanger the power system security by increasing the risk of blackouts. This coordination problem involves many other issues such as communication, abstraction and last but not least optimization. This first part of the paper is devoted to the principals of the coordination control, addressing some of those issues using as a case study the problem of coordination control for avoiding voltage collapse in large-scale multi-area power systems.

scholarly journals An Interval Mathematic-Based Methodology for Reliable Resilience Analysis of Power Systems in the Presence of Data Uncertainties

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6632
Author(s):  
Antonio Pepiciello ◽  
Alfredo Vaccaro ◽  
Loi Lei Lai
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transition Probabilities ◽  
Transient State ◽  
Data Uncertainty ◽  
Transition Matrices ◽  
Power Networks ◽  
Novel Approach ◽  
Impact Events

Prevention and mitigation of low probability, high impact events is becoming a priority for power system operators, as natural disasters are hitting critical infrastructures with increased frequency all over the world. Protecting power networks against these events means improving their resilience in planning, operation and restoration phases. This paper introduces a framework based on time-varying interval Markov Chains to assess system’s resilience to catastrophic events. After recognizing the difficulties in accurately defining transition probabilities, due to the presence of data uncertainty, this paper proposes a novel approach based on interval mathematics, which allows representing the elements of the transition matrices by intervals, and computing reliable enclosures of the transient state probabilities. The proposed framework is validated on a case study, which is based on the resilience analysis of a power system in the presence of multiple contemporary faults. The results show how the proposed framework can successfully enclose all the possible outcomes obtained through Monte Carlo simulation. The main advantages are the low computational burden and high scalability achieved.

scholarly journals Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Guillermo Martínez-Lucas ◽  
José Ignacio Sarasúa ◽  
Juan Ignacio Pérez-Díaz ◽  
Sergio Martínez ◽  
Danny Ochoa
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Variable Speed ◽  
El Hierro

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

scholarly journals Using surface velocities to calculate ice thickness and bed topography: a case study at Columbia Glacier, Alaska, USA

2012 ◽  
Vol 58 (212) ◽  
pp. 1151-1164 ◽  
Author(s):  
R.W. Mcnabb ◽  
R. Hock ◽  
S. O’Neel ◽  
L.A. Rasmussen ◽  
Y. Ahn ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Computational Time ◽  
Ice Thickness ◽  
Thickness Change ◽  
Bed Topography ◽  
Surface Data ◽  
Direct Measurements ◽  
The Mean ◽  
Time Required

AbstractInformation about glacier volume and ice thickness distribution is essential for many glaciological applications, but direct measurements of ice thickness can be difficult and costly. We present a new method that calculates ice thickness via an estimate of ice flux. We solve the familiar continuity equation between adjacent flowlines, which decreases the computational time required compared to a solution on the whole grid. We test the method on Columbia Glacier, a large tidewater glacier in Alaska, USA, and compare calculated and measured ice thicknesses, with favorable results. This shows the potential of this method for estimating ice thickness distribution of glaciers for which only surface data are available. We find that both the mean thickness and volume of Columbia Glacier were approximately halved over the period 1957–2007, from 281 m to 143 m, and from 294 km3 to 134 km3, respectively. Using bedrock slope and considering how waves of thickness change propagate through the glacier, we conduct a brief analysis of the instability of Columbia Glacier, which leads us to conclude that the rapid portion of the retreat may be nearing an end.

Power systems expansion considering large wind farms. Case study: Western Romania power system

2011 ◽  
Author(s):  
Dan Jigoria-Oprea ◽  
Stefan Kilyeni ◽  
Constantin Barbulescu ◽  
Gabriela Prostean ◽  
Florin Claudiu Solomonesc ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Wind Farms ◽  
Large Wind ◽  
Western Romania

scholarly journals Simultaneous Inertia Contribution and Optimal Grid Utilization with Wind Turbines

2019 ◽  
Author(s):  
Clemens Jauch ◽  
Arne Gloe
Keyword(s):  
Power Systems ◽  
Power System ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Power Plants ◽  
Frequency Control ◽  
Negative Consequences ◽  
Realistic Case ◽  
Continuous Feed

This paper presents findings of a study on continuous feed-in management and continuous synthetic inertia contribution with wind turbines. A realistic case study, based on real measurements, is outlined. A wind turbine feeds into a weak feeder, such that its power has to be adapted to the permissible loading of this feeder. At the same time the wind turbine is to provide inertia to the grid by applying the previously published variable inertia constant controller. It is discussed that optimal grid utilisation and simultaneous inertia contribution are mandatory for the frequency control in power systems that are heavily penetrated with renewable energies. The study shows that continuous feed-in management can be combined well with continuous inertia provision. There are hardly any negative consequences for the wind turbine. The benefits for the grid are convincing, both in terms of increased system utilisation and in terms of provided inertia. It is concluded that wind turbines can enhance angular stability in a power system to a larger extent than conventional power plants.

scholarly journals The Effects of Social Distancing on Electricity Demand Considering Temperature Dependency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 473
Author(s):  
Mohannad Alkhraijah ◽  
Maad Alowaifeer ◽  
Mansour Alsaleh ◽  
Anas Alfaris ◽  
Daniel K. Molzahn
Keyword(s):  
Power System ◽  
Social Activity ◽  
Electricity Consumption ◽  
Electricity Demand ◽  
Electric Grid ◽  
Temperature Changes ◽  
Social Distancing ◽  
Novel Coronavirus ◽  
Time Required

To mitigate the spread of the Novel Coronavirus (COVID-19), governments around the world have imposed social distancing policies ranging from minor social activity suspensions to full curfews. These social distancing policies have altered electricity consumption behaviors in numerous countries. Many governments imposed strict social distancing policies during a temperature transition season where the impacts of temperature variations are particularly important for the operation of the electric grid. This paper studies how strict social distancing policies affect the relationship between electricity demand and ambient temperature. We first review the expected short- and long-term impacts of social distancing on the electricity demand. We then present a case study on the electricity demand of the Kingdom of Saudi Arabia during strict social distancing policies. The results of this case study suggest that strict social distancing policies result in a stronger correlation between temperature and electricity demand compared to previous years. Additionally, we observe a reduction in the time required for the electricity demand to respond to temperature changes. Power system regulators can use the results in this paper to better design energy policies. The results can also be used by power system operators to more accurately forecast electricity demands and avoid inefficient and insecure operation of the electric grid.

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