scholarly journals TIDEA: A Control System Fine Tuning Software Tool Applied to a Large Power Station

2001 ◽  
Vol 34 (14) ◽  
pp. 273-278
Author(s):  
Francesco Pretolani ◽  
George Oluwande ◽  
Giambattista Garbossa ◽  
Megan Boardman
Keyword(s):  
Control System ◽  
Software Tool ◽  
Fine Tuning ◽  
Power Station ◽  
Large Power ◽  
Tuning Software

scholarly journals Electrical Damping Assessment and Sensitivity Analysis of a Liquefied Natural Gas Plant: Experimental Validation

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4084
Author(s):  
Lorenzo Bongini ◽  
Rosa Anna Mastromauro ◽  
Daniele Sgrò ◽  
Fabrizio Malvaldi
Keyword(s):  
Sensitivity Analysis ◽  
Control System ◽  
Natural Gas ◽  
Experimental Validation ◽  
Power Conversion ◽  
Liquefied Natural Gas ◽  
Fine Tuning ◽  
Simulation Platform ◽  
Electrical Damping ◽  
Conversion Stage

Liquefied Natural Gas (LNG) plants are commonly island-operated weak grids where the interaction of high-power Variable Frequency Drives (VFDs) with the Turbine-Generator (TG) units might cause Sub-Synchronous Torsional Interaction (SSTI) phenomena. SSTI phenomena can lead the LNG plant to instability conditions. Each LNG plant configuration is characterized by a risk level, which is considered high when the electrical damping at the TG Torsional Natural Frequencies (TNFs) is negative. Starting from a real case study, a detailed electromechanical model of an LNG plant is presented. The model is comprehensive of the control system of the power conversion stage and of the TG unit. Sensitivity analysis, performed on control system parameters, allows one to detect the parameters that impact the electrical damping and the stability of the overall LNG plant. A complete simulation platform is developed. Experimental results are carried out on a real LNG plant considering four different configurations. The theoretical model and the simulation platform allow one to estimate the electrical damping and the results are confirmed by the experimental validation. It is demonstrated that fine tuning of the power conversion stage control parameters can reduce the risk related to torsional instability.

Scale and Lag Effects on Control of Aerodynamic Power and Loads on a HAWT Rotor

2001 ◽  
Vol 123 (4) ◽  
pp. 339-345 ◽  
Author(s):  
P. J. Moriarty ◽  
A. J. Eggers, ◽  
K. Chaney ◽  
W. E. Holley
Keyword(s):  
Control System ◽  
Fatigue Life ◽  
Wind Speed ◽  
Open Loop ◽  
Time Lags ◽  
Large Power ◽  
Lag Effects ◽  
Mean Wind Speed ◽  
The Mean ◽  
High Control

The effects of rotor scale and control system lag were examined for a variable-speed wind turbine. The scale study was performed on a teetered rotor with radii ranging between 22.5m and 33.75m. A 50% increase in radius more than doubled the rated power and annual energy capture. Using blade pitch to actively control fluctuating flatwise moments allowed for significant reductions in blade mass for a fixed fatigue life. A blade operated in closed-loop mode with a 33.75m radius weighed less than an open-loop blade with a 22.5m radius while maintaining the same fatigue life of 5×109 rotations. Actuator lag reduced the effectiveness of the control system. However, 50% reductions in blade mass were possible even when implementing a relatively slow actuator with a 1 sec. time constant. Other practical limits on blade mass may include fatigue from start/stop cycles, non-uniform turbulence, tower wake effects, and wind shear. The more aggressive control systems were found to have high control accelerations near 60 deg/s2, which may be excessive for realistic actuators. Two time lags were introduced into the control system when mean wind speed was estimated in a rapidly changing wind environment. The first lag was the length of time needed to determine mean wind speed, and therefore the mean control settings. The second was the frequency at which these mean control settings were changed. Preliminary results indicate that quickly changing the mean settings (every 10 seconds) and using a moderate length mean averaging time (60 seconds) resulted in the longest fatigue life. It was discovered that large power fluctuations occurred during open-loop operation which could cause sizeable damage to a realistic turbine generator. These fluctuations are reduced by one half or more when aerodynamic loads are actively controlled.

Decentralized Control of Large Power System by H ∞ Control Based Excitation Control System

1999 ◽  
Vol 32 (2) ◽  
pp. 7370-7375
Author(s):  
Shigen Cui ◽  
Hiroyuki Ukai ◽  
Hisashi Kando ◽  
Koichi Nakamura ◽  
Hideki Fujita
Keyword(s):  
Control System ◽  
Power System ◽  
Decentralized Control ◽  
Excitation Control ◽  
Large Power

scholarly journals A novel measurement-based procedure for dynamic equivalents of electric power systems for stability studies using improved sine cosine algorithm

2019 ◽  
Vol 70 (6) ◽  
pp. 454-464
Author(s):  
Omar Benmiloud ◽  
Salem Arif
Keyword(s):  
Power Systems ◽  
Dynamic Properties ◽  
Specific Area ◽  
Pattern Search ◽  
Fine Tuning ◽  
Large Power ◽  
Area Of Interest ◽  
Starting Point ◽  
Sine Cosine Algorithm ◽  
Dynamic Equivalent

Abstract Dynamic equivalent (DE) is an important process of multi-area interconnected power systems. It allows to perform stability assessment of a specific area (area of interest) at minimum cost. This study is intended to investigate the dynamic equivalent of two relatively large power systems. The fourth-order model of synchronous generators with a simplified excitation system is used as equivalent to the group of generators in the external system. To improve the accuracy of the estimated model, the identification is carried in two stages. First, using the global search Sine Cosine Algorithm (SCA) to find a starting set values, then this set is used as starting point for the fine-tuning made through the Pattern Search (PS) algorithm. To increase the reliability of the model’s parameters, two disturbances are used to avoid the identification based on a specific event. The developed program is applied on two standard power systems, namely, the New England (NE) system and the Northeast Power Coordinating Council (NPCC) system. Simulation results confirm the ability of the optimized model to preserve the main dynamic properties of the original system with accuracy.

Depth from Dichoptic Edges Depends on Vergence Tuning

Perception ◽  
1983 ◽  
Vol 12 (4) ◽  
pp. 425-438 ◽  
Author(s):  
Jodi D Krol ◽  
Wim A van de Grind
Keyword(s):  
Spatial Distribution ◽  
Control System ◽  
Normal Subjects ◽  
Fine Tuning ◽  
Fixation Disparity ◽  
Low Contrast ◽  
Fixation Distance ◽  
Depth Vision ◽  
Opposite Contrast ◽  
Paradoxical Results

Small but reproducible fixation disparities occur in normal subjects when they view certain types of dichoptic stimuli. During dichoptic as well as stereoptic stimulation the motor fusion process determines first the average vergence state of the eyes. The subsequent fine tuning of vergence is shown to depend on the spatial distribution of contrast edges both of the same contrast sign (‘stereoptic edges’) and of opposite contrast sign (‘dichoptic edges’). Stereoptic edges tend to induce superposition attempts of the vergence control system and dichoptic edges tend to antagonise this process. If a single low-contrast dichoptic edge is presented with zero disparity and within a stereoptic reference frame, a fixation disparity of several minutes of arc results. This influences depth vision since dichoptic edges are perceived (as monocular edges) at the actual rather than at the intended fixation distance. The findings explain previous paradoxical results of eg Kaufman and Pitblado who reported seeing depth in opposite-contrast stereograms. Their results seemed to contradict the well-established ‘same-sign rule’ (SSR) which states that the stereoptic system only detects disparities of edges with the same contrast sign. It is concluded that (i) the SSR holds; (ii) dichoptic (and monocular) edges are seen at the horopter; (iii) the vergence fine tuning prevents superposition of dichoptic edges even if this causes a fixation disparity.

Design of a fast frequency modulation control system based on photovoltaic power station

2021 ◽  
Author(s):  
Ye Hairui ◽  
Ao Bing ◽  
Bai Song ◽  
Deng Xingyan ◽  
Xu Dongshu ◽  
...  
Keyword(s):  
Control System ◽  
Frequency Modulation ◽  
Power Station ◽  
Photovoltaic Power ◽  
Modulation Control

Smart Polygeneration Grid: Control and Optimization System

2012 ◽  
Author(s):  
Maximiliano Bozzo ◽  
Francesco Caratozzolo ◽  
Alberto Traverso
Keyword(s):  
Control System ◽  
Working Conditions ◽  
Minimization Problem ◽  
Power Supply ◽  
Supply And Demand ◽  
Software Tool ◽  
Test Cases ◽  
Urban District ◽  
Constrained Minimization Problem ◽  
Different Levels

This study aims at the development of a software tool for supply and demand matching of electrical and thermal energy in an urban district. In particular, the tool has been developed for E-NERDD, the experimental district that TPG-DIMSET is going to build in Savona, Italy. E-NERDD is an acronym for Energy and Efficiency Research Demonstration District. It is one of the districts that will be used within the project to demonstrate how different software tools and algorithms perform in thermodynamic, economic and environmental terms. The software tool originally developed for and implemented in this work, called E-NERDD Control System, is targeted on enabling the operation of the hardware, when connected in a district mode. Supply and demand are matched to reach a thermoeconomic optimum. An optimization algorithm is organized into two different levels of optimization: a first level that resolves a constrained minimization problem in planning power supply for each generator on the basis of day-before forecasting; and a second level that distributes among the different machines the gap between planned and real-time demand. The algorithm developed is demonstrated in four test cases in order to test it in different working conditions.

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