Power System Operator in Mexico Reveals Millions in Savings by Updating Its Short-Term Thermal Unit Commitment Model

2016 ◽  
Vol 46 (6) ◽  
pp. 493-502 ◽  
Author(s):  
José L. Ceciliano-Meza ◽  
Juan Álvarez López ◽  
Armando De la Torre Sánchez ◽  
Rolando Nieva Gómez ◽  
Isaías Guillén Moya ◽  
...  
Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 716
Author(s):  
Karol Wawrzyniak ◽  
Endika Urresti Padrón ◽  
Wojciech Jaworski ◽  
Roman Korab

Risk-based redispatch optimization is proposed as a methodology to support the Transmission System Operator (TSO) with preventive remedial actions obtained by extending the security-constrained unit commitment/economic dispatch with constraints resulting from the risk assessed for the power system. Although being heuristic, the methodology is based on comprehensive dynamic security assessment as time-domain simulations are used, allowing to express the degree of all types of instabilities, e.g., caused by contingencies, in monetary terms. Therefore, the risk is assessed as the expected value of the cost incurred by the TSO. Such an approach forms a new pathway to including risk in planning procedures already used by TSOs. Results obtained for the IEEE39 dynamic power system, with costs assigned to load shedding and generator tripping due to single transmission lines short-circuits, are shown as a reference case.


Author(s):  
Amit Tiwari ◽  
Adarsh Dhar Dubey ◽  
And Devesh Patel

The term load forecast refers to the projected load requirement using systematic process of defining load in sufficient quantitative detail so that important power system expansion decisions can be made. Load forecasting is necessary for economic generation of power, economic allocation between plants (unit commitment scheduling), maintenance scheduling & for system security such as peak load shaving by power interchange with interconnected utilities. With structural changes to electricity in recent years, there is an emphasis on Short Term Load Forecasting (STLF).STLF is the essential part of power system planning & operation. Basic operating functions such as unit commitment, economic dispatch, and fuel scheduling & unit maintenance can be performed efficiently with an accurate forecast. Short term load forecasting can help to estimate load flows & to make decisions that can prevent overloading. Timely implementations of such decisions lead to improvement of network reliability & to the reduced occurrences of equipment failures & blackouts. The aim of short term load forecasting is to predict future electricity demands based, traditionally on historical data and predicted weather conditions. Short term load forecasting in its basic form is a statistical problem, where in the previous load values (time series variables) and influencing factors (casual variables) are used to determine the future loads.


2021 ◽  
Author(s):  
Yu Peng

Power systems worldwide are embracing diverse supply mixes that incorporate a significant portion from renewables such as wind and solar energy. Wind energy is characterised by reliable equipment, but with an output that is uncertain and intermittent. In addition to equipment unreliability (system N-1 criterion), output uncertainties of wind electric generators (WEGs) introduce risk into daily power system schedules. This risk from the uncertainty of output from WEGs can be quantified as expected energy not served (EENS). Furthermore, the introduction of new forms of generation changes the methods of operating transmission systems, further necessitating the use of transmission security constraints in power systems optimization algorithms. This dissertation explores new approaches to stochastically model the real power output of WEGs and to efficiently tackle AC transmission system security constraints for power system optimization algorithms such as optimal power flow (OPF) and day-ahead unit commitment (UC). Usually, normal probabilistic distribution is used to model uncertainty in short-term wind power output forecast and compute EENS. In this dissertation, a new triangular approximate distribution (TAD) model is proposed which is a linear approximation of normal probabilistic distribution to model short-term wind power output forecast and compute EENS. This TAD model is used to formulate a practical risk-constrained fast OPF for transmission systems to simultaneously minimize: 1) risk due to uncertainties in power output from WEGs, and 2) the total operating cost. The integration of new energy resources causes transmission systems to operate in new, challenging, and often unforeseen operating states. Thus, it is imperative that UC algorithms incorporate AC transmission system security constraints and stochastically model output of WEGs to ensure reliable operation of transmission systems. As a first step, a successive mixed integer linear programming (MILP) method is proposed for AC transmission system security constrained unit commitment (SCUC) challenge. Fuzzy sets theory is used to model infeasible constraints in this MILP formulation. As a next step, the TAD model of WEGs is integrated into the MILP formulation of SCUC to create a fast security and risk constrained probabilistic UC algorithm. The two UC algorithms are tested on large systems.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8529
Author(s):  
Dhanuja Lekshmi J ◽  
Zakir Hussain Rather ◽  
Bikash C Pal

With diminishing fossil fuel resources and increasing environmental concerns, large-scale deployment of Renewable Energy Sources (RES) has accelerated the transition towards clean energy systems, leading to significant RES generation share in power systems worldwide. Among different RES, solar PV is receiving major focus as it is most abundant in nature compared to others, complimented by falling prices of PV technology. However, variable, intermittent and non-synchronous nature of PV power generation technology introduces several technical challenges, ranging from short-term issues, such as low inertia, frequency stability, voltage stability and small signal stability, to long-term issues, such as unit commitment and scheduling issues. Therefore, such technical issues often limit the amount of non-synchronous instantaneous power that can be securely accommodated by a grid. In this backdrop, this research work proposes a tool to estimate maximum PV penetration level that a given power system can securely accommodate for a given unit commitment interval. The proposed tool will consider voltage and frequency while estimating maximum PV power penetration of a system. The tool will be useful to a system operator in assessing grid stability and security under a given generation mix, network topology and PV penetration level. Besides estimating maximum PV penetration, the proposed tool provides useful inputs to the system operator which will allow the operator to take necessary actions to handle high PV penetration in a secure and stable manner.


2013 ◽  
Vol 392 ◽  
pp. 586-592
Author(s):  
Xiao Hui Wang ◽  
Li Zi Zhang ◽  
Zhuo Xin Sun ◽  
Shi Jun Cheng

This paper proposed an approach to evaluate the economics of pumped-storage unit from the perspective of the power system. An MIP-based unit commitment model with multi-type units was established, which integrated thermal, CCGT, hydro, wind, nuclear and pumped-storage units. Based on the model the net present value of pumped-storage per megawatt was calculated and compared with the capital cost per megawatt, which produce the economic result of pumped-storage. The case study proved the feasibility of the above model and approach. Furthermore, the change of economic result of pumped-storage over system variables like nuclear capacity, wind capacity and regulating capacity of thermal unit was analyzed. The case study showed that with the increase of nuclear capacity, wind capacity and minimum output of thermal units, the economics of pumped-storage was improved.


1982 ◽  
Vol 15 (1) ◽  
pp. 589-594
Author(s):  
D.P. Kothari ◽  
I.J. Nagrath ◽  
J. Nanda

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