Non-linear Total Energy Optimisation of a Fleet of Power Plants

2007 ◽  
pp. 88-96
Author(s):  
Lars Nolle ◽  
Friedrich Biegler-König ◽  
Peter Deeskow
Keyword(s):  
Total Energy ◽  
Power Plants ◽  
Non Linear ◽  
Energy Optimisation

A Novel Non-Linear Programming-Based Coal Blending Technology for Power Plants

2000 ◽  
Vol 78 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Chungen Yin ◽  
Zhongyang Luo ◽  
Junhu Zhou ◽  
Kefa Cen
Keyword(s):  
Linear Programming ◽  
Power Plants ◽  
Non Linear Programming ◽  
Coal Blending ◽  
Non Linear

A Hybrid Fuzzy Controller for Industrial Power Plants

1995 ◽  
Author(s):  
A. de Sam Lazaro ◽  
W. Steffenhagan
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Fuzzy Controller ◽  
Control Process ◽  
Automated Control ◽  
Linear Behavior ◽  
Non Linear ◽  
Plant Operations ◽  
Control Decision ◽  
Computer Based

Abstract The automation of the control to a power plant is indeed a challenge mainly because of the occurrences of random and unpredictable variations in output demands as well as because of highly non-linear behavior of the system itself [1]. It is sometimes argued that the ‘best’ control for a power plant is the operators themselves. Experienced operators are capable of taking decisions on the basis of incomplete and imprecise information. The extent to which these decisions are correct is a matter of speculation. Erroneous conclusions, established post facto, are chalked up to the learning process and in fact, contribute to the forming of a good, experienced control team. The need to automate the control process for a plant is even more acutely felt when considering the complexity of the plants themselves and the volume of data that would have to be processed before a control decision can be taken. Factored into this decision would also be several governing parameters such as costs, reliability, other constraints and their interdependancy, as well as planned and unscheduled outages for maintenance and so on. In this paper, however, only one facet of a power plant operation is considered. It is intended to demonstrate that thermal efficiency may be improved by better techniques for automated control of throttle valves in the steam turbine of the plant. One of these options, fuzzy logic, is selected, and defended, as being the more effective than current techniques. A comparative analysis is conducted of control techniques for plant operations followed by a brief overview of fuzzy control and its application to control of non-linear systems. A method of applying this ‘new’ computer-based technique to control of non-linear, somewhat erratic plants is presented and discussed.

scholarly journals Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 357 ◽  
Author(s):  
Oz Sorkin ◽  
Eliyahu Farber ◽  
Moshe Averbukh
Keyword(s):  
Time Constant ◽  
Power Plants ◽  
Numerical Procedure ◽  
Voltage Regulation ◽  
Solar Irradiation ◽  
Approximation Procedure ◽  
Non Linear ◽  
Low Pass ◽  
Linear Circuits ◽  
Selection Of

Widespread use of photovoltaic (PV) small and middle-power plants close or inside existing townships and villages may cause significant deviations of the grid voltage. Owing to the oscillation of solar irradiation and corresponding power flows these voltage instabilities can damage equipment and must be prevented. Designated for the voltage regulation tap-changers in distribution transformers located in a significant distance of such settlements have a sluggish response time. As a possible answer for their delay is the smoothing energy of flows in PV power installation by intermittent capacitor low-pass filtering (LPF) located near those PV facilities. The application of ultracapacitors (UC) for LPF is remarkable due to their sustainability and relatively low costs of energy storage. The parameters selection of such appliances is a well-designed procedure for linear circuits. However, DC–AC inverters in PV facilities are represented by a power (instead of a voltage) source. As a result, the total circuit including such LPF becomes a non-linear and its transient process and consequently, its efficiency is difficult to assess requiring each time of development the UC storage an application complex numerical procedure. Engineers are usual to work with linear circuits that are describing fine by a time constant is designated as a multiplication of a capacitance times load equivalent resistance. In the case of PV DC–AC inverters, such an approach can be applied as well but a value of a time constant should be corrected. Considering a significant cost of UC storage, the non-optimal selection of a correcting coefficient may cause considerable loses. Submitted in the presented article is an original approximation procedure giving an efficiently approachable technique to select correcting coefficient for describing non-linear dynamic process by its linear analog. This way the development low-pass UC filtering in electrical systems with PV plants becomes more efficient and simpler task.

scholarly journals Повышение астатизма системы автоматического управления путем введения положительной обратной связи

2020 ◽  
Vol 43 (2) ◽  
Author(s):  
ANDREY KHANNANOV ◽  
KIRA CHUPINA ◽  
VALERY USOLTCEV
Keyword(s):  
Automatic Control ◽  
Control Systems ◽  
Positive Feedback ◽  
Power Plants ◽  
Proportional Integral ◽  
Automatic Control Systems ◽  
Non Linear ◽  
Additional Positive Feedback

Подчиненные системы автоматического управления (САУ) широко используются в технике, в том числе в судовых энергетических установках. Необходимость ограничения параметров объекта управления, таких как синхронный генератор или судовой электропривод, делает их нелинейными. Применение пропорционально-интегральных регуляторов создает проблему «интегрального насыщения», возникновения свободных движений в САУ при сходе регуляторов с ограничения. Авторами предлагается повысить астатизм САУ и решить проблему «интегрального насыщения» путем введения дополнительной положительной обратной связи с выхода объекта управления в пропорциональный канал регулятора. Эффективность таких САУ исследовалась нами с помощью анализа математических моделей нелинейных САУ и их цифрового моделирования. Результаты исследования: описана математическая модель одного из контуров САУ с дополнительной положительной обратной связью. Доказано, что введение такого вида связи позволяет увеличить астатизм САУ и исключить эффект «интегрального насыщения» при астатизме первого порядка, что повышает точность САУ при отработке управляющих сигналов. Предложен новый способ исключения эффекта «интегрального насыщения» в широкодиапазонных регуляторах напряжения судовых синхронных генераторов промысловых систем освещения без применения аппаратных защитных средств. Таким образом, доказана эффективность введения дополнительной положительной обратной связи на увеличение точности САУ и исключения эффекта «интегрального насыщения». Отмечена низкая чувствительность эффекта введения положительной обратной связи к изменению параметров САУ. Subordinate automatic control systems (SACS) are widely used in engineering inclusive of ship power plants. The need to limit specific parameters of the object makes them non-linear. The use of proportional-integral regulators leads to the problem of integral saturation, the emergence of free movements in SACS when the regulators descend from the limit. The authors propose to increase astatism of SACS and solve the problem of integral saturation by introducing additional positive feedback.

Total Energy Investment in Nuclear Power Plants

1975 ◽  
Vol 26 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Charles T. Rombough ◽  
Billy V. Koen
Keyword(s):  
Total Energy ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Energy Investment

scholarly journals Non-Linear Stability Analysis of Real Signals from Nuclear Power Plants (Boiling Water Reactors) based on Noise Assisted Empirical Mode Decomposition Variants and the Shannon Entropy

2017 ◽  
Author(s):  
Omar A. Olvera-Guerrero ◽  
Alfonso Prieto-Guerrero ◽  
Gilberto Espinosa-Paredes
Keyword(s):  
Empirical Mode Decomposition ◽  
Shannon Entropy ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Boiling Water ◽  
Boiling Water Reactors ◽  
Mode Decomposition ◽  
Non Linear ◽  
Water Reactors

There are currently around 78 Nuclear Power Plants (NPP) in the world based on Boiling Water Reactors (BWR). The current parameter to assess BWR instability issues is the linear Decay Ratio (DR). However, it is well known that BWRs are complex non-linear dynamical systems that may even exhibit chaotic dynamics that normally preclude the use of the DR when the BWR is working at a specific operating point during instability. In this work a novel methodology based on an adaptive Shannon Entropy estimator and on Noise Assisted Empirical Mode Decomposition variants is presented. This methodology was developed for real-time implementation of a stability monitor. This methodology was applied to a set of signals stemming from several NPPs reactors (Ringhals-Sweden, Forsmark-Sweden and Laguna Verde-Mexico) under commercial operating conditions, that experienced instabilities events, each one of a different nature

Aeromechanical Characterization of a Last Stage Steam Blade at Low Load Operation: Part 2 — Computational Modelling and Comparison

2020 ◽  
Author(s):  
Lorenzo Pinelli ◽  
Federico Vanti ◽  
Lorenzo Peruzzi ◽  
Andrea Arnone ◽  
Andrea Bessone ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Computational Modelling ◽  
Test Facility ◽  
Nonlinear Phenomena ◽  
Aerodynamic Damping ◽  
Low Load ◽  
Non Linear ◽  
Last Stage ◽  
Load Conditions

Abstract This paper is part of a two-part publication that aims to experimentally and numerically evaluate the aerodynamic and mechanical damping of a last stage ST blade at low load operation. A three-stage downscaled steam turbine with a snubbered last stage moving blade LSMB has been tested in the T10MW test facility of Doosan Skoda Power R&D Department in the context of the FLEXTURBINE European project (Flexible Fossil Power Plants for the Future Energy Market through new and advanced Turbine Technologies). Aerodynamic and flutter simulations of different low load conditions have been performed. The acquired data are used to validate the unsteady CFD approach for the prediction of the aerodynamic damping in terms of logarithmic decrement. Numerical results have been achieved through an upgraded version of the URANS CFD solver, selecting appropriate and robust numerical setups for the simulation of very low load conditions, such as increased condenser pressure at the exhaust hood outlet. The numerical methods for blade aerodamping estimation are based on the computation of the unsteady pressure response caused by the row vibration. They are usually classified in time-linearized, harmonic balance and non-linear approaches both in frequency and time domain. The validation of all these methods historically started in the field of aeronautical low-pressure turbines and has been gradually extended to compressor blades and steam turbine rows. For the analysis of a steam turbine last rotor blade operating at strong part load conditions, non-linear methods are recommended as these approaches are able to deal with strong nonlinear phenomena such as shock waves and massive flow separations inside the domain. Experimental data have been used to separate the contributions of mechanical and aerodynamic damping, extrapolating to zero mass flow the total measured damping. Finally, the comparisons between the aerodynamic damping coming from measurements and CFD results have been reported in order to highlight the capability to properly predict the last stage blade flutter stability at low load conditions. Such comparisons confirms the flutter free design of the new snubbered LSMB blade.

scholarly journals A Non-Linear Rainfall-Runoff Model with a Sigmoid Gain Factor to Simulate Flow Frequency Distribution Curves for Amazon Catchments

2011 ◽  
Vol 59 (3) ◽  
pp. 145-156 ◽  
Author(s):  
Marco Vinagre ◽  
Claudio Blanco ◽  
André Amarante Mesquita
Keyword(s):  
Frequency Distribution ◽  
Power Plants ◽  
Gain Factor ◽  
Performance Criteria ◽  
Rainfall Runoff ◽  
Process Data ◽  
Non Linear ◽  
Flow Frequency ◽  
Rainfall Runoff Model ◽  
Runoff Model

A Non-Linear Rainfall-Runoff Model with a Sigmoid Gain Factor to Simulate Flow Frequency Distribution Curves for Amazon Catchments The objective of this paper is to simulate flow frequency distribution curves for Amazon catchments with the aim of scaling power generation from small hydroelectric power plants. Thus, a simple nonlinear rainfall-runoff model was developed with sigmoid-variable gain factor due to the moisture status of the catchment, which depends on infiltration, and is considered a factor responsible for the nonlinearity of the rainfall-runoff process. Data for a catchment in the Amazon was used to calibrate and validate the model. The performance criteria adopted were the Nash-Sutcliffe coefficient (R2), the RMS, the Q95% frequencyc flow percentage error, and the mean percentage errors ranging from Q5% to Q95%.. Calibration and validation showed that the model satisfactorily simulates the flow frequency distribution curves. In order to find the shortest period of rainfall-runoff data, which is required for applying the model, a sensitivity analysis was performed whereby rainfall and runoff data was successively reduced by 1 year until a 1.5-year model application minimum period was found. This corresponds to one hydrological year plus the 6-month long "memory". This analysis evaluates field work in the ungauged sites of the region.

Sign in / Sign up

Export Citation Format

Share Document