scholarly journals Reliability Worth Assessment in Composite Power System Planning and Operation

2014 ◽  
Vol 8 (5) ◽  
pp. 45
Author(s):  
Ali Khraiwish Dalabeeh ◽  
Eng.Hani Hasan Saleh Al-Hajbi
Keyword(s):  
Power System ◽  
Unit Commitment ◽  
Economic Effect ◽  
Cost Benefit ◽  
Electric Power System ◽  
Reliability Indices ◽  
Operational Solution ◽  
The Cost ◽  
Operational Constraints

This study presents a comprehensive procedure for evaluating the reliability indices incorporating reduction in interruption cost, and to relate reliability investments with customer’s benefits. An analytical algorithm is used to obtain the final optimal operational solution by determining unit commitment for each generating unit to reach the maximum profit (minimizing cost) subjected to operational constraints. The paper describes a method based on the complementing short-term planning with long-term planning take into account the cost benefit approach. The proposed method has been demonstrated on the RBTS to show the feasibility and the economic effect of the proposed method, and was applied to the Jordanian Electric Power System (JEPS) to show its application capability.

scholarly journals Unit Commitment Problem in Electrical Power System: A Literature Review

2018 ◽  
Vol 8 (3) ◽  
pp. 1357 ◽  
Author(s):  
Idriss Abdou ◽  
Mohamed Tkiouat
Keyword(s):  
Literature Review ◽  
Power System ◽  
Unit Commitment ◽  
Electrical Power ◽  
Mathematical Formulation ◽  
Electric Power System ◽  
Electrical Power System ◽  
Unit Commitment Problem ◽  
Commitment Problem ◽  
Operational Constraints

Unit commitment (UC) is a popular problem in electric power system that aims at minimizing the total cost of power generation in a specific period, by defining an adequate scheduling of the generating units. The UC solution must respect many operational constraints. In the past half century, there was several researches treated the UC problem. Many works have proposed new formulations to the UC problem, others have offered several methodologies and techniques to solve the problem. This paper gives a literature review of UC problem, its mathematical formulation, methods for solving it and Different approaches developed for addressing renewable energy effects and uncertainties.

scholarly journals A meliorated Harris Hawks optimizer for combinatorial unit commitment problem with photovoltaic applications

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ayani Nandi ◽  
Vikram Kumar Kamboj
Keyword(s):  
Power Generation ◽  
Power System ◽  
Electric Power ◽  
Unit Commitment ◽  
Renewable Energy Sources ◽  
Electric Power System ◽  
Unit Commitment Problem ◽  
Spinning Reserve ◽  
Commitment Problem ◽  
Sine Cosine Algorithm

AbstractConventional unit commitment problem (UCP) consists of thermal generating units and its participation schedule, which is a stimulating and significant responsibility of assigning produced electricity among the committed generating units matter to frequent limitations over a scheduled period view to achieve the least price of power generation. However, modern power system consists of various integrated power generating units including nuclear, thermal, hydro, solar and wind. The scheduling of these generating units in optimal condition is a tedious task and involves lot of uncertainty constraints due to time carrying weather conditions. This difficulties come to be too difficult by growing the scope of electrical power sector day by day, so that UCP has connection with problem in the field of optimization, it has both continuous and binary variables which is the furthermost exciting problem that needs to be solved. In the proposed research, a newly created optimizer, i.e., Harris Hawks optimizer (HHO), has been hybridized with sine–cosine algorithm (SCA) using memetic algorithm approach and named as meliorated Harris Hawks optimizer and it is applied to solve the photovoltaic constrained UCP of electric power system. In this research paper, sine–cosine Algorithm is used for provision of power generation (generating units which contribute in electric power generation for upload) and economic load dispatch (ELD) is completed by Harris Hawks optimizer. The feasibility and efficacy of operation of the hybrid algorithm are verified for small, medium power systems and large system considering renewable energy sources in summer and winter, and the percentage of cost saving for power generation is found. The results for 4 generating units, 5 generating units, 6 generating units, 7 generating units, 10 generating units, 19 generating units, 20 generating units, 40 generating units and 60 generating units are evaluated. The 10 generating units are evaluated with 5% and 10% spinning reserve. The efficacy of the offered optimizer has been verified for several standard benchmark problem including unit commitment problem, and it has been observed that the suggested optimizer is too effective to solve continuous, discrete and nonlinear optimization problems.

scholarly journals Can newborn screening be cost benefit procedure if preventing serious complications of cystic fibrosis?

2021 ◽  
pp. 020-023
Author(s):  
Šubat-Dežulović Mirna ◽  
Pelčić Gordana ◽  
Valković Ana ◽  
Flajšman-Raspor Sanja ◽  
Pelčić Goran ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Metabolic Alkalosis ◽  
Cost Benefit ◽  
Inherited Disease ◽  
Eu Countries ◽  
Life Threatening ◽  
Long Term Prognosis ◽  
The Cost

Cystic Fibrosis (CF) is a common inherited disease with reported mean prevalence of 0.737/10,000 in 27 EU countries (Farrell J Cyst Fibros. 2008). Still, many EU countries have not implemented CF in the Newborn Screening (NBS) programme, including our country. We report the case of a 7-month-old boy whose presenting signs of CF were life-threatening neurological symptoms caused by severe metabolic alkalosis and hypoelectrolytemia. By presenting this case, we argue hoping to persuade the authorities in any country that the available newborn screening for CF is the cost benefit procedure in preventing life treating consequences with the obvious impact on the long-term prognosis of this chronic disease.

scholarly journals Unit commitment based on modified firefly algorithm

2020 ◽  
Vol 53 (3-4) ◽  
pp. 320-327 ◽  
Author(s):  
Balasim M Hussein ◽  
Aqeel S Jaber
Keyword(s):  
Power System ◽  
Firefly Algorithm ◽  
Unit Commitment ◽  
Second Step ◽  
Priority List ◽  
Load Demand ◽  
List Method ◽  
The Cost ◽  
Commitment Problems ◽  
Modified Firefly Algorithm

Optimization technologies have drawn considerable interest in power system research. The success of an optimization process depends on the efficient selection of method and its parameters based on the problem to be solved. Firefly algorithm is a suitable method for power system operation scheduling. This paper presents a modified firefly algorithm to address unit commitment issues. Generally, two steps are involved in solving unit commitment problems. The first step determines the generating units to be operated, and the second step calculates the amount of demand-sharing among the units (obtained from the first step) to minimize the cost that corresponds to the load demand and constraints. In this work, the priority list method was used in the first step and the second step adopted the modified firefly algorithm. Ten generators were selected to test the proposed method, while the values of the cost function were regarded as criteria to gauge and compare the modified firefly algorithm with the classical firefly algorithm and particle swarm optimization algorithms. Results show that the proposed approach is more efficient than the other methods in terms of generator and error selections between load and generation.

scholarly journals Cost-Effectiveness of a Problem-Solving Intervention Aimed to Prevent Sickness Absence among Employees with Common Mental Disorders or Occupational Stress

2020 ◽  
Vol 17 (14) ◽  
pp. 5234
Author(s):  
Marijke Keus Van De Poll ◽  
Gunnar Bergström ◽  
Irene Jensen ◽  
Lotta Nybergh ◽  
Lydia Kwak ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Problem Solving ◽  
Mental Disorders ◽  
Sickness Absence ◽  
Common Mental Disorders ◽  
Cost Benefit ◽  
Cost Effective ◽  
Production Loss ◽  
The Cost

The cost-benefit and cost-effectiveness of a work-directed intervention implemented by the occupational health service (OHS) for employees with common mental disorders (CMD) or stress related problems at work were investigated. The economic evaluation was conducted in a two-armed clustered RCT. Employees received either a problem-solving based intervention (PSI; n = 41) or care as usual (CAU; n = 59). Both were work-directed interventions. Data regarding sickness absence and production loss at work was gathered during a one-year follow-up. Bootstrap techniques were used to conduct a Cost-Benefit Analysis (CBA) and a Cost-Effectiveness Analysis (CEA) from both an employer and societal perspective. Intervention costs were lower for PSI than CAU. Costs for long-term sickness absence were higher for CAU, whereas costs for short-term sickness absence and production loss at work were higher for PSI. Mainly due to these costs, PSI was not cost-effective from the employer’s perspective. However, PSI was cost-beneficial from a societal perspective. CEA showed that a one-day reduction of long-term sickness absence costed on average €101 for PSI, a cost that primarily was borne by the employer. PSI reduced the socio-economic burden compared to CAU and could be recommended to policy makers. However, reduced long-term sickness absence, i.e., increased work attendance, was accompanied by employees perceiving higher levels of production loss at work and thus increased the cost for employers. This partly explains why an effective intervention was not cost-effective from the employer’s perspective. Hence, additional adjustments and/or support at the workplace might be needed for reducing the loss of production at work.

scholarly journals Risk-Based Active Power Redispatch Optimization

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 716
Author(s):  
Karol Wawrzyniak ◽  
Endika Urresti Padrón ◽  
Wojciech Jaworski ◽  
Roman Korab
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Unit Commitment ◽  
Load Shedding ◽  
Security Assessment ◽  
Reference Case ◽  
Dynamic Security Assessment ◽  
System Operator ◽  
Remedial Actions ◽  
The Cost

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.

scholarly journals Tail regeneration after autotomy revives survival: a case from a long-term monitored lizard population under avian predation

2017 ◽  
Vol 284 (1847) ◽  
pp. 20162538 ◽  
Author(s):  
Jhan-Wei Lin ◽  
Ying-Rong Chen ◽  
Ying-Han Wang ◽  
Kuen-Chih Hung ◽  
Si-Min Lin
Keyword(s):  
Cost Benefit ◽  
Predation Pressure ◽  
Natural Conditions ◽  
Tail Regeneration ◽  
Tail Loss ◽  
Avian Predators ◽  
Predatory Birds ◽  
The Cost ◽  
Caudal Autotomy

Caudal autotomy in lizards has intrigued scientists for more than 100 years. Because of the relative lack of literature under natural conditions, the complicated association among field autotomy rate, real predation pressure, the long-term cost of tail loss, and the benefit of regeneration remains equivocal. In this study, we conducted a 7-year capture–mark–recapture (CMR) programme with a wild population of a sexually dichromatic lizard, Takydromus viridipunctatus . We used autotomy indexes and a contemporary bird census mega-dataset of four predatory birds as predictors to examine the association between tail loss and predation pressure. We further estimated the survival cost of tail loss and alleviation by regeneration under natural conditions through CMR modelling. We found that large and small avian predators affect lizard survival through the following two routes: the larger-sized cattle egret causes direct mortality while the smaller shrikes and kestrels are the major causes of autotomy. Following autotomy, the survival rate of tailless individuals over the next month was significantly lower than that of tailed individuals, especially males during the breeding season, which showed a decline of greater than 30%. This sex-related difference further demonstrated the importance of reproductive costs for males in this sexually dichromatic species. However, the risk of mortality returned to baseline after the tails were fully grown. This study indicates the benefit of tail regeneration under natural conditions, which increases our understanding of the cost–benefit dynamics of caudal autotomy and further explains the maintenance of this trait as an evolutionarily beneficial adaption to long-term predator–prey interactions.

scholarly journals Development of Energy Systems Planning Methods

2020 ◽  
Vol 209 ◽  
pp. 02005
Author(s):  
Nikolay Belyaev ◽  
Andrey Egorov ◽  
Nikolay Korovkin ◽  
Vladimir Chudny
Keyword(s):  
Power System ◽  
Electric Power ◽  
Energy Systems ◽  
Electric Power System ◽  
Systems Planning ◽  
Planning Methods

The article is devoted to improving the methods of planning the development of an electric power system (hereinafter - EPS) for the long term. The list of tasks to be solved when planning the development of EPS, the formulation of the task of substantiating the development of EPS, and the features of its solution are considered. Within the framework of the study of the multicriteria formulation of the problem of substantiating the development of EPS, possible criteria for planning an EPS are proposed. Calculations were performed for two and four criteria. Based on the results obtained, conclusions were drawn about the prospects of a multicriteria approach to planning the development of EPS.

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