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Modelling of Steam Turbine Generators from Heat Balance Diagram and Determination of Frequency Response
Issue:
Volume 2, Issue 1, June 2018
Pages:
1-15
Received:
21 July 2018
Accepted:
8 August 2018
Published:
5 September 2018
DOI:
10.11648/j.cse.20180201.11
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Abstract: In the power system, apart from ensuring the availability of Power, maintaining the power system frequency is of utmost important. The intent is to ensure stabilized frequency to the consumers at all times and maintain load frequency control of the power grid which requires necessarily the power load operators and regulators to manage generation and distribution services efficiently to maintain reliability of the power system frequency. In an interconnected power system the power load demand varies randomly which impacts both the frequency and tie-line power interchange. Hence, it is necessary to develop a methodology to make decisions synchronously and automatically by all grid connected generating units. The load frequency control along with restricted governor mode control address this issue and minimizes the deviations in the power grid frequency and tie-line power interchange bringing the steady state errors to zero and maintaining the balance between demand and supply in real time. Restricted governor mode control is a primary frequency control but with inclusion of a dead band of governor not exceeding + / - 0.03 Hz where primary control is blocked by the governor dead band unlike free governor mode. This ripple factor of + / - 0.03 Hz prevents continuous hunting in the governor due to very small frequency variation. Restricted governor mode control does not act in proportion to the frequency deviation like free governor and is not strictly a frequency controlling mode, rather this mode restrict sudden and large frequency deviation with an additional step load disturbance during drop of normal running frequency under contingency control which operate along with load frequency controller enhancing the generation of power. In order to ensure the same, the precision Restricted Governor Mode Control is necessary simultaneously for all the power grid connected generating stations and to define the methodology close to accurate derivation of the various parameters for the modelling of turbine is necessary. This paper describe the procedure for deriving the parameters of a steam turbo generator model of a typical 660 MW Ultra-supercritical machine from heat and mass balance diagram and the conceptual load frequency control with restricted governor mode control. The main focus of the work is to determine the various time constants and finding the frequency response of a typical steam turbine generator based on a realistic mathematical model using the heat and mass balance data with some thermodynamic assumptions. The simulated model response for various scenarios are also presented in this paper.
Abstract: In the power system, apart from ensuring the availability of Power, maintaining the power system frequency is of utmost important. The intent is to ensure stabilized frequency to the consumers at all times and maintain load frequency control of the power grid which requires necessarily the power load operators and regulators to manage generation an...
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Comparative Analysis of PID, IMC, Infinite H Controllers for Frequency Control in Hydroelectric Plants
Korassaï,
Yeremou Tamtsia Aurelien,
Haman Djalo,
Ngaleu Gildas Martial,
Ndzana Jean Calvin
Issue:
Volume 2, Issue 1, June 2018
Pages:
16-26
Received:
23 November 2018
Accepted:
18 December 2018
Published:
14 January 2019
DOI:
10.11648/j.cse.20180201.12
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Abstract: One of the most important criteria for the stability of electrical networks, is the frequency of the voltage produced. This frequency is subjected to the hazards of the load connected to the turbo generator group. Indeed, the balance of the frequency results from the balance between active power produced by the turbo alternator group and power demanded by the load connected to the network. This paper presents a comparative study of three methods of regulation to solve the problem of frequency fluctuations in hydroelectric plants: modified Proportional–Integral–Derivative (PID) control, Internal Model Control (IMC) and Infinite Horizon (H∞) Control. Simulation model in the presence of these has been established in Matlab / Simulink. The results of the simulation have subsequently revealed their robustness, which demonstrates once again their reliability.
Abstract: One of the most important criteria for the stability of electrical networks, is the frequency of the voltage produced. This frequency is subjected to the hazards of the load connected to the turbo generator group. Indeed, the balance of the frequency results from the balance between active power produced by the turbo alternator group and power dema...
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Numerical Method of a Class of Stochastic Delay Population Models
Changyou Wang,
Kaixiang Yang,
Xingcheng Pu,
Rui Li
Issue:
Volume 2, Issue 1, June 2018
Pages:
27-35
Received:
1 December 2018
Accepted:
19 December 2018
Published:
14 January 2019
DOI:
10.11648/j.cse.20180201.13
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Abstract: Our aim in this paper is to present the design and implementation of a new numerical method to solve a class of stochastic delay population models. Firstly, a stochastic predator-prey model with time-delay and white noise is established. And then, a numerical simulation method based on the Milstein method is proposed to simulate the stochastic population model. Finally, the numerical solutions of the population model are obtained by using MATLAB software. The simulation results show that the new numerical simulation method can truly reflect the persistence and extinction process of stochastic predator-prey model, and provide a reference for solving the numerical simulation of the similar population models.
Abstract: Our aim in this paper is to present the design and implementation of a new numerical method to solve a class of stochastic delay population models. Firstly, a stochastic predator-prey model with time-delay and white noise is established. And then, a numerical simulation method based on the Milstein method is proposed to simulate the stochastic popu...
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Synthesis of a Digital Corrector for Frequency Control in Hydroelectric Power Plants
Korassaï,
Yeremou Tamtsia Aurelien,
Haman-Djalo,
Samba Aimé Hervé,
Ngaleu Gildas Martial
Issue:
Volume 2, Issue 1, June 2018
Pages:
36-49
Received:
26 November 2018
Accepted:
17 December 2018
Published:
22 January 2019
DOI:
10.11648/j.cse.20180201.14
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Abstract: The safety and reliability of an electricity grid is defined by the quality of the power supplied to consumers. One of the important criteria for the stability of electrical networks is the frequency of the voltage produced. The aim of this paper is to develop digital corrector applied to the speed control system correcting on turbines to resolve the frequency variations problems in the output of the alternator caused by the imbalance between the active power produced by the turbo-generator and the power required by the load connected to the grid in the hydroelectric plants. First, a modeling of the turbine, the servo valve - servomotor assembly, the valve - flow function, the power chain as well as the alternator of the power station is presented. Then, three controllers (Proportional–Integral–Derivative, Internal Model Control and Robust Structure Theory) are studied, simulated and their performances were tested and compared in terms of instruction tracking and robustness. The simulations were realized by MATLAB/Simulink software. For the hydroelectric power plant studied, the RST controller has the best performance.
Abstract: The safety and reliability of an electricity grid is defined by the quality of the power supplied to consumers. One of the important criteria for the stability of electrical networks is the frequency of the voltage produced. The aim of this paper is to develop digital corrector applied to the speed control system correcting on turbines to resolve t...
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Optimizing a Cloud Model for Effective and Efficient Collaboration in a Virtual World
Chinedu Paschal Uchenna,
Ariagiegbe Ambrose,
Adegher Pascal,
Okoye Echezona Dozie
Issue:
Volume 2, Issue 1, June 2018
Pages:
50-65
Received:
26 November 2018
Accepted:
17 December 2018
Published:
22 January 2019
DOI:
10.11648/j.cse.20180201.15
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Abstract: The challenge of how organisations can establish global connection or alliance under the backbone of an ICT intensive infrastructure to leverage on the core competences of other organisations for effective and efficient operation in a virtual world in order to create virtual values to serve its corporate objectives has created the opportunity for the rise of the global Cloud champions with different cloud services to meet organisations technological and business needs. Harnessing this concept, organisations are able to exist without the bricks and mortar by taking advantage of technology by using the Internet as well as its offspring- cloud, for collaboration, communication, gathering information, e-Commerce, and marketing. Thus, this research paper responds to the concern on how an organization can be enabled to collaborate in a virtual organization (VO) so as to operate effectively and efficiently under an ICT intensive cloud platform to create value or enhance corporate visibility and competitiveness in the globally digitised business environment. This research develops a novel hybrid cloud-based framework (tagged: Cloud VO) that integrates existing cloud computing models with the VVC Framework of Virtual Organisation (VO) for effective and efficient collaboration to ensure corporate visibility and competitiveness in the virtual environment. Further, a hypothetic deductive methodology (quantitative approach) involving survey approach was advanced to meet the establish objectives, as well as derive a mathematical model for effective and efficient VO operations within the proposed cloud-based framework. The model, if deployed would create corporate value or enhance corporate visibility and competitiveness in the globally digitised business environment. It would further ensure customer satisfaction, shareholder wealth creation and overall stakeholder value creation through optimised collaborative virtual world.
Abstract: The challenge of how organisations can establish global connection or alliance under the backbone of an ICT intensive infrastructure to leverage on the core competences of other organisations for effective and efficient operation in a virtual world in order to create virtual values to serve its corporate objectives has created the opportunity for t...
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