Methodology to evaluate contribution of thermal power plant flexibility to power system stability when increasing share of renewable energies: Classification and additional fuel cost of flexible operation

Fuel ◽  
2021 ◽  
Vol 292 ◽  
pp. 120352
Author(s):  
Fumihiko Yoshiba ◽  
Yuji Hanai ◽  
Isamu Watanabe ◽  
Hiromi Shirai
Author(s):  
Zulfiqar Ali Shahani

Electrical power system without interruption is the need of every consumer. Therefore, supplying electrical power which must be efficient, reliable and secure from any disturbance is the priority of power supply companies. But, due to changes in weather conditions and continuous load variations, small disturbances arise which may lead to severe disturbance. All electrical generating stations are interconnected, so a failure in any one unit can affect other generating units, therefore analysis is compulsory to solve the problem in the least time, and avoid a further big loss. Analysis of steady-state stability or transient stability plays a key role in a power system which helps to understand the behavior of a dynamic system. The stability problem is concerned with the behavior of the generating station when the system puts on either small or large disturbance. In this work, the steady-state stability (SSS) analysis of the Jamshoro thermal power plant (JTPP) is analyzed by using the eigenvalue method and linearization technique at four different reheat gain values. We develop a nonlinear mathematical model of JTPP and discuss its linearized form, and examine the behavior of the system stability using eigenvalues. The eigenvalue method analyzes the behavior of synchronous machine when system load varies continually. Numerical values of eigenvalues consist of either real part or real as well as imaginary parts. These eigenvalues help to understand the stability of the system, as to whether the system is stable or not.


Author(s):  
Muhammad Nizam Kamarudin ◽  
Nabilah Mohd Shaharudin ◽  
Mohd Hafiz Jali ◽  
Sahazati Md. Rozali ◽  
Mohd Shahrieel Mohd Aras

Tehnika ◽  
2021 ◽  
Vol 76 (4) ◽  
pp. 447-456
Author(s):  
Zdravko Milovanović ◽  
Valentina Janičić-Milovanović ◽  
Dejan Branković

Determining the reliability of a thermal power plant as a whole or in its individual components often requires long and very expensive tests under special operating modes on a very large number of samples or gathering the required exploitation data, which is even more difficult because of the choice of a general mathematical method (different forms of curves which quantitatively define reliability with different failure density functions and the high dependence of such curves on changes in the operating modes of components and environmental conditions). The introduction of approximate calculations, in order to overcome these problems, gives an insight into the basic reliability characteristics of the observed system as a whole, but also insufficiently exact final parameters, due to a whole series of larger or smaller approximations, as well as the inability to take into account all existing influences (development of new technologies, specifics newly developed disorders, etc.). Calculating the reliability of a complex system is only the first initial phase of verifying quantitative characteristics, that is, the hypothesis itself that we have more or less confidence in. Their final acceptance or rejection is a verification of reliability through the control of certain quantitative system indicators for the given technical conditions of operation. For these reasons, alternative terms are often used to verify reliability in the literature, such as reliability control or hypothesis testing. Designing a reliability model, through the application of simulation methods, to select the best parameters for the functioning of components and systems as a whole, in technological terms, should be supported by appropriate experimental methods (using collected data and stored data from the past). This paper provides an analysis of the application of the Markov process to assess the reliability of a complex thermal power system, with the aim of scheduling appropriate decisions on maintenance actions based on the required level of reliability. The optimum timing of replacement / repair of parts of a complex thermal power system is defined before its failure or the need to act correctively. Also, these models serve to provide a level of reliability by carrying out adequate maintenance actions on complex units within the thermal power plant.


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