Frequency security constrained short-term unit commitment

Lei, Xianzhang; Lerch, E.; Xie, Congjun

doi:10.1016/s0378-7796(01)00177-8

Cited by 21 publications

(9 citation statements)

References 10 publications

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“…This problem is formally defined as the Unit Commitment (UC) and Economic Dispatch (ED) problems. The general objective of both is to minimize the total operating cost, while satisfying all of the constraints so that a given security level can be met [14,42,43]. The UC problem studies which generators must be in operation at certain time instant, while the ED studies, once the generators connected to the grid are known, the power that must be supplied by each of them.…”

Section: Problem Descriptionmentioning

confidence: 99%

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An Evolutionary Computational Approach for the Problem of Unit Commitment and Economic Dispatch in Microgrids under Several Operation Modes

et al. 2019

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In the last decades, new types of generation technologies have emerged and have been gradually integrated into the existing power systems, moving their classical architectures to distributed systems. Despite the positive features associated to this paradigm, new problems arise such as coordination and uncertainty. In this framework, microgrids constitute an effective solution to deal with the coordination and operation of these distributed energy resources. This paper proposes a Genetic Algorithm (GA) to address the combined problem of Unit Commitment (UC) and Economic Dispatch (ED). With this end, a model of a microgrid is introduced together with all the control variables and physical constraints. To optimally operate the microgrid, three operation modes are introduced. The first two attend to optimize economical and environmental factors, while the last operation mode considers the errors induced by the uncertainties in the demand forecasting. Therefore, it achieves a robust design that guarantees the power supply for different confidence levels. Finally, the algorithm was applied to an example scenario to illustrate its performance. The achieved simulation results demonstrate the validity of the proposed approach.

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Section: Problem Descriptionmentioning

confidence: 99%

“…Once the UC is solved, the Economic Dispatch (ED) is responsible for assigning the generation reference to the programmed units, satisfying the power demand together with the physical constraints of the grid [14]. Sometimes, this problem is tackled considering the possible uncertainty in the power generated of the RES or the demand.…”

Section: Introductionmentioning

confidence: 99%

An Evolutionary Computational Approach for the Problem of Unit Commitment and Economic Dispatch in Microgrids under Several Operation Modes

et al. 2019

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“…Therefore, a loss of generation will cause the system frequency to fall dramatically. In order to ensure a stable operation with the lowest impact on the system, the disturbed power balance must be equalized within a short-specified time by activating the reserve of on-line units or by load shedding or both [12].…”

Section: Introductionmentioning

confidence: 99%

Hydropower Plants Frequency Regulation Depending on Upper Reservoir Water Level

Platero

Sánchez

Nicolet³

et al. 2019

Energies

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This paper presents a novel method of hydro power plant operation, based on the control of the injectors’ or wicked gates opening time as a function of the upper reservoir level. In this way, a faster power injection, depending on the current water level on the upper reservoir, could be achieved. When this level is higher, the opening time could be shorter; hence, hydropower ramps could be steeper. Due to this control, frequency excursions and load shedding trips are smaller, thus the power quality is enhanced. This method has been tested and validated by computer simulations in a case study located in El Hierro island, Canary Archipelago (Spain). The simulations made show significant improvements, dependent on upper reservoir water level, in power quality.

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“…Incorporating transmission constraints into the UC optimization problem significantly increases the problem's size and the resulting computational burden. A literature survey shows that the DC model is widely used to model the transmission network constraints when solving the SCUC problem . Based on a DC‐based model, the decision variables in the binary commitment problem are the status of power units, the binary start‐up status, and the binary shutdown status.…”

Section: Introductionmentioning

confidence: 99%

“…A literature survey shows that the DC model is widely used to model the transmission network constraints when solving the SCUC problem. [6][7][8][9][10] Based on a DC-based model, the decision variables in the binary commitment problem are the status of power units, the binary start-up status, and the binary shutdown status. In addition, the decision variables in the operational problem are the voltage-phase angles and the active power generation.…”

Section: Introductionmentioning

confidence: 99%

A computational comparison of 2 mathematical formulations to handle transmission network constraints in the unit commitment problem

Hinojosa

Gutiérrez-Alcaraz

2017

Int. Trans. Electr. Energ. Syst.

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Summary Until recently, transmission network constraints have been incorporated into the unit commitment (UC) problem (security‐constrained UC [SCUC]) using the classical direct current (DC)–based equation. This paper proposes a new formulation to model network constraints in the UC problem by using the power transfer distribution factor (PTDF). The classical formulation uses the binary commitment status, the power generation, and the voltage‐phase angles as decision variables. For the proposed formulation, the nodal balance equality constraints are modeled using one equality constraint, and the transmission network constraints have been modeled using the PTDF and the active power generation (decision variables). The main advantage of this formulation is the reduction of decision variables in the operation problem in comparison with the classical DC formulation. Transmission losses, using a piecewise linear approximation, are included in the SCUC problem as well. Both formulations are validated and tested on the Institute of Electrical and Electronics Engineers (IEEE) 14‐bus, the IEEE 30‐bus, the IEEE 57‐bus, and the IEEE 118‐bus. The IEEE 14‐bus and IEEE 57‐bus systems are used to compare the loss and the lossless models. The results show that the PTDF‐based formulation, which requires fewer continuous variables and equality constraints than the classical DC formulation, reduces the simulation time without sacrificing optimality. The results also demonstrate the feasibility of the proposed formulation to address the SCUC problem and its potential applicability to medium‐scale and large‐scale power systems.

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Frequency security constrained short-term unit commitment

Cited by 21 publications

References 10 publications

An Evolutionary Computational Approach for the Problem of Unit Commitment and Economic Dispatch in Microgrids under Several Operation Modes

An Evolutionary Computational Approach for the Problem of Unit Commitment and Economic Dispatch in Microgrids under Several Operation Modes

Hydropower Plants Frequency Regulation Depending on Upper Reservoir Water Level

A computational comparison of 2 mathematical formulations to handle transmission network constraints in the unit commitment problem

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