scholarly journals Risk-Limiting Real-Time Economic Dispatch in a Power System with Flexibility Resources

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3133 ◽  
Author(s):  
Hongji Lin ◽  
Chongyu Wang ◽  
Fushuan Wen ◽  
Chung-Li Tseng ◽  
Jiahua Hu ◽  
...  
Keyword(s):  
Power System ◽  
Real Time ◽  
Value At Risk ◽  
Renewable Energy Sources ◽  
Economic Dispatch ◽  
Conditional Value At Risk ◽  
Operational Flexibility ◽  
Practical Applications ◽  
Start Up ◽  
The Impact

The integration of numerous intermittent renewable energy sources (IRESs) poses challenges to the power supply-demand balance due to the inherent intermittent and uncertain power outputs of IRESs, which requires higher operational flexibility of the power system. The deployment of flexible ramping products (FRPs) provides a new alternative to accommodate the high penetration of IRESs. Given this background, a bi-level risk-limiting real-time unit commitment/real-time economic dispatch model considering FRPs provided by different flexibility resources is proposed. In the proposed model, the objective is to maximize the social surplus while minimizing the operational risk, quantified using the concept of conditional value-at-risk (CVaR). Energy and ramping capabilities of conventional generating units during the start-up or shut-down processes are considered, while meeting the constraints including unit start-up/shut-down trajectories and ramping up/down rates in consecutive time periods. The Karush–Kuhn–Tucker (KKT) optimality conditions are then used to convert the bi-level programming problem into a single-level one, which can be directly solved after linearization. The modified IEEE 14-bus power system is employed to demonstrate the proposed method, and the role of FRPs in enhancing the system flexibility and improving the accommodation capability for IRESs is illustrated in some operation scenarios of the sample system. The impact of the confidence level in CVaR on the system operational flexibility is also investigated through case studies. Finally, a case study is conducted on a regional power system in Guangdong Province, China to demonstrate the potential of the proposed method for practical applications.

scholarly journals A Generalized Unit Commitment and Economic Dispatch Approach for Analysing the Polish Power System under High Renewable Penetration

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1952
Author(s):  
Marcin Pluta ◽  
Artur Wyrwa ◽  
Wojciech Suwała ◽  
Janusz Zyśk ◽  
Maciej Raczyński ◽  
...  
Keyword(s):  
Power System ◽  
Energy Policy ◽  
Power Plants ◽  
System Analysis ◽  
Unit Commitment ◽  
Renewable Energy Sources ◽  
Economic Dispatch ◽  
System Stability ◽  
Mixed Integer ◽  
The Impact

The achievement of carbon neutrality requires a deep transformation of the Polish power sector. This paper analyses the impact of increased electricity generation from wind and solar technologies envisaged in the newest version of the Energy Policy of Poland until 2040 on the operation of dispatchable generators in 2030. The analysis was carried out using the Model of Economic Dispatch and Unit commitment for System Analysis (MEDUSA) model, which solves a mixed integer problem related to unit commitment and economic dispatch in electrical power production. At first, the model was validated based on the real operation data from 2018. Next, five scenarios were built to analyse the operation of the system in 2030. The overall result of the study is that the safest solution from the point of view of power system stability is to extend the decommissioning of coal units of 200 and 300 MW classes, to invest in renewable energy sources (RES) according to the energy policy, to build new gas power plants with the total capacity of ca. 4 GW, and to enforce Demand Side Management (DSM) programs for shifting the electrical load. The proposed framework for the optimization of power system planning helps to avoid wrong investment decisions that would have a negative impact on energy prices.

OPTIMAL REINSURANCE FROM THE VIEWPOINTS OF BOTH AN INSURER AND A REINSURER UNDER THE CVAR RISK MEASURE AND VAJDA CONDITION

2021 ◽  
pp. 1-29
Author(s):  
Yanhong Chen
Keyword(s):  
Loss Function ◽  
Value At Risk ◽  
Numerical Study ◽  
Risk Measure ◽  
Convex Combination ◽  
Weighting Factor ◽  
Loss Functions ◽  
Conditional Value At Risk ◽  
Optimal Reinsurance ◽  
The Impact

ABSTRACT In this paper, we study the optimal reinsurance contracts that minimize the convex combination of the Conditional Value-at-Risk (CVaR) of the insurer’s loss and the reinsurer’s loss over the class of ceded loss functions such that the retained loss function is increasing and the ceded loss function satisfies Vajda condition. Among a general class of reinsurance premium principles that satisfy the properties of risk loading and convex order preserving, the optimal solutions are obtained. Our results show that the optimal ceded loss functions are in the form of five interconnected segments for general reinsurance premium principles, and they can be further simplified to four interconnected segments if more properties are added to reinsurance premium principles. Finally, we derive optimal parameters for the expected value premium principle and give a numerical study to analyze the impact of the weighting factor on the optimal reinsurance.

scholarly journals Transient Impact Analysis of High Renewable Energy Sources Penetration According to the Future Korean Power Grid Scenario

2018 ◽  
Vol 10 (11) ◽  
pp. 4140 ◽  
Author(s):  
Seungchan Oh ◽  
Heewon Shin ◽  
Hwanhee Cho ◽  
Byongjun Lee
Keyword(s):  
Renewable Energy ◽  
Power System ◽  
Electric Power ◽  
Power Plants ◽  
Transient Stability ◽  
Impact Analysis ◽  
Renewable Energy Sources ◽  
Electric Power System ◽  
Energy Sources ◽  
The Impact

Efforts to reduce greenhouse gas emissions constitute a worldwide trend. According to this trend, there are many plans in place for the replacement of conventional electric power plants operating using fossil fuels with renewable energy sources (RESs). Owing to current needs to expand the RES penetration in accordance to a new National power system plan, the importance of RESs is increasing. The RES penetration imposes various impacts on the power system, including transient stability. Furthermore, the fact that they are distributed at multiple locations in the power system is also a factor which makes the transient impact analysis of RESs difficult. In this study, the transient impacts attributed to the penetration of RESs are analyzed and compared with the conventional Korean electric power system. To confirm the impact of the penetration of RESs on transient stability, the effect was analyzed based on a single machine equivalent (SIME) configuration. Simulations were conducted in accordance to the Korean power system by considering the anticipated RES penetration in 2030. The impact of RES on transient stability was provided by a change in CCT by increasing of the RES penetration.

scholarly journals Operational Planning and Bidding for District Heating Systems with Uncertain Renewable Energy Production

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3310 ◽  
Author(s):  
Ignacio Blanco ◽  
Daniela Guericke ◽  
Anders Andersen ◽  
Henrik Madsen
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Electricity Markets ◽  
Electricity Market ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Operational Planning ◽  
Solution Approach ◽  
The Impact

In countries with an extended use of district heating (DH), the integrated operation of DH and power systems can increase the flexibility of the power system, achieving a higher integration of renewable energy sources (RES). DH operators can not only provide flexibility to the power system by acting on the electricity market, but also profit from the situation to lower the overall system cost. However, the operational planning and bidding includes several uncertain components at the time of planning: electricity prices as well as heat and power production from RES. In this publication, we propose a planning method based on stochastic programming that supports DH operators by scheduling the production and creating bids for the day-ahead and balancing electricity markets. We apply our solution approach to a real case study in Denmark and perform an extensive analysis of the production and trading behavior of the DH system. The analysis provides insights on system costs, how DH system can provide regulating power, and the impact of RES on the planning.

ASSET CORRELATIONS IN TURBULENT MARKETS AND THE IMPACT OF DIFFERENT REGIMES ON ASSET MANAGEMENT

2011 ◽  
Vol 28 (01) ◽  
pp. 1-23 ◽  
Author(s):  
GERMAN BERNHART ◽  
STEPHAN HÖCHT ◽  
MICHAEL NEUGEBAUER ◽  
MICHAEL NEUMANN ◽  
RUDI ZAGST
Keyword(s):  
Risk Aversion ◽  
Asset Management ◽  
Value At Risk ◽  
Conditional Value At Risk ◽  
Dependence Structure ◽  
The Us ◽  
The Mean ◽  
Asian Market ◽  
Asset Classes ◽  
The Impact

In this article, the dependence structure of the asset classes stocks, government bonds, and corporate bonds in different market environments and its implications on asset management are investigated for the US, European, and Asian market. Asset returns are modelled by a Markov-switching model which allows for two market regimes with completely different risk-return structures. Using major stock indices from all three regions, calm and turbulent market periods are identified for the time period between 1987 and 2009 and the correlation structures in the respective periods are compared. It turns out that the correlations between as well as within the asset classes under investigation are far from being stable and vary significantly between calm and turbulent market periods as well as in time. It also turns out that the US and European markets are much more integrated than the Asian and US/European ones. Moreover, the Asian market features more and longer turbulence phases. Finally, the impact of these findings is examined in a portfolio optimization context. To accomplish this, a case study using the mean-variance and the mean-conditional-value-at-risk framework as well as two levels of risk aversion is conducted. The results show that an explicit consideration of different market conditions in the modelling framework yields better portfolio performance as well as lower portfolio risk compared to standard approaches. These findings hold true for all investigated optimization frameworks and risk-aversion levels.

Coordinating Supply Chain with Buy-Back Contracts in the Presence of Risk Aversion

2018 ◽  
Vol 35 (02) ◽  
pp. 1840008 ◽  
Author(s):  
Chunlin Luo ◽  
Xin Tian ◽  
Xiaobing Mao ◽  
Qiang Cai
Keyword(s):  
Supply Chain ◽  
Risk Aversion ◽  
Value At Risk ◽  
Performance Measure ◽  
Expected Profit ◽  
Conditional Value At Risk ◽  
Allocation Rule ◽  
Risk Averse ◽  
Buy Back ◽  
The Impact

This paper addresses the operational decisions and coordination of the supply chain in the presence of risk aversion, where the risk averse retailer’s performance is measured by a combination of the expected profit and conditional value-at-risk (CVaR). Such performance measure reflects the desire of the retailer to maximize the expected profit on one hand and to control the downside risk of the profit on the other hand. The impact of risk aversion on the supply chain’s decision and performance is also explored. To overcome the inefficiency due to the double marginalization and the aggravation resulting from risk aversion, we investigate the buy-back contract to coordinate the supply chain. Such contract can largely increase the supply chain’s profit, especially when the retailer is more risk averse. Lastly, we extend such risk measure to the widely-used business model nowadays — platform selling model, and explore the impact of the allocation rule on the manufacturer’s decision.

scholarly journals Dynamic economic dispatch of wind-storage combined system based on conditional value-at-risk

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Yi Zheng ◽  
Xiaoqing Bai
Keyword(s):  
At Risk ◽  
Energy Storage ◽  
Value At Risk ◽  
Economic Dispatch ◽  
Second Order ◽  
Mixed Integer ◽  
Conditional Value At Risk ◽  
Combined System ◽  
Dynamic Economic Dispatch ◽  
Bus System

AbstractWind power's uncertainty is from the intermittency and fluctuation of wind speed, which brings a great challenge to solving the power system's dynamic economic dispatch problem. With the wind-storage combined system, this paper proposes a dynamic economic dispatch model considering AC optimal power flow based on Conditional Value-at-Risk ($$CVaR$$ CVaR ). Since the proposed model is hard to solve, we use the big-M method and second-order cone description technique to transform it into a trackable mixed-integer second-order conic programming (MISOCP) model. By comparing the dispatching cost of the IEEE 30-bus system and the IEEE 118-bus system at different confidence levels, it is indicated that $$CVaR$$ CVaR method can adequately estimate dispatching risk and assist decision-makers in making reasonable dispatching schedules according to their risk tolerance. Meanwhile, the optimal operational energy storage capacity and initial/final energy storage state can be determined by analyzing the dispatching cost risk under different storage capacities and initial/final states.

Control of BESS Using Frequency-Linked Pricing with High Wind Penetration

2014 ◽  
Vol 511-512 ◽  
pp. 1099-1102
Author(s):  
Zhen Bao Sun
Keyword(s):  
Wind Speed ◽  
Real Time ◽  
Wind Power ◽  
Renewable Energy Sources ◽  
Storage System ◽  
Energy Storage System ◽  
Test System ◽  
High Wind ◽  
Battery Energy ◽  
The Impact

Recently, many countries have been pushing for a higher share of renewable energy sources, especially wind, in their generation mix. However, the intermittent and uncertain nature of wind power imposes a limit on the extent it can replace the conventional generation resources. In a high wind penetration scenario, the Battery Energy Storage System (BESS) offers a solution to the grid operation problems. The purpose of this paper is to evaluate the merits of price-based operation of BESS in a real-time market with high wind penetration using frequency-linked pricing. The authors propose a real-time market in which real-time prices are based on the grid frequency. A model for real-time price-based operation of a conventional generator and a BESS is presented. Simulations for different wind penetration scenarios are carried out on an isolated area test system. Wind speed sequence is generated using composite wind speed model. A simplified model of wind speed to power conversion is adopted to observe the impact of increase in wind power generation on the grid frequency and the real-time prices.

scholarly journals Application of Synchrophasor Measurements for Improving Situational Awareness of the Power System

2018 ◽  
Vol 55 (2) ◽  
pp. 3-10
Author(s):  
A. Obushevs ◽  
A. Mutule
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Real Time ◽  
Situational Awareness ◽  
Renewable Energy Sources ◽  
Electric Power System ◽  
Energy Sources ◽  
Scada Systems

Abstract The paper focuses on the application of synchrophasor measurements that present unprecedented benefits compared to SCADA systems in order to facilitate the successful transformation of the Nordic-Baltic-and-European electric power system to operate with large amounts of renewable energy sources and improve situational awareness of the power system. The article describes new functionalities of visualisation tools to estimate a grid inertia level in real time with monitoring results between Nordic and Baltic power systems.

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