scholarly journals Calculations of Electromechanical Eigenvalues Based on Generating Unit Instantaneous Power and Angular Speed Waveforms at a Step Disturbance

2015 ◽  
pp. 68-73 ◽  
Author(s):  
Piotr Pruski ◽  
Stefan Paszek
Keyword(s):  
Angular Speed ◽  
Instantaneous Power ◽  
Step Disturbance

scholarly journals Assessment of Polish Power System angular stability based on analysis of different disturbance waveforms

2015 ◽  
Vol 63 (2) ◽  
pp. 435-441
Author(s):  
P. Pruski ◽  
S. Paszek
Keyword(s):  
Power System ◽  
Angular Speed ◽  
Voltage Regulation ◽  
Rectangular Pulse ◽  
Angular Stability ◽  
Regulation System ◽  
Synchronous Generators ◽  
State Matrix ◽  
Instantaneous Power ◽  
Gradient Algorithms

Abstract The paper presents investigation results concerning assessment of the Polish Power System (PPS) angular stability based on power system state matrix eigenvalues associated with electromechanical phenomena, when using the angular stability factors calculated on the basis of these eigenvalues. The eigenvalues were calculated by analysis of the disturbance waveforms of the instantaneous power, angular speed and power angle of synchronous generators in PPS generating units when taking into account introduction of a disturbance to different units. There was assumed a disturbance in the form of a rectangular pulse introduced to the voltage regulation system of a generating unit. There was also analysed the effect of the duration of the introduced test disturbance on the calculation results of the eigenvalue influencing the measurement waveforms of the instantaneous power of generating unit no 5 in Rybnik Power Plant. The method for eigenvalue calculations used in the investigations consists in approximation of the disturbance waveforms in particular generating units with the use of the waveforms being a superposition of the modal components associated with the searched eigenvalues. The hybrid optimisation algorithm being a serial combination of the genetic and gradient algorithms was used for computations

scholarly journals Use of Pareto optimisation for tuning power system stabilizers

2012 ◽  
Vol 60 (1) ◽  
pp. 125-131
Author(s):  
S. Paszek
Keyword(s):  
Power System ◽  
Optimal Solution ◽  
Angular Speed ◽  
Power System Stabilizers ◽  
Instantaneous Power ◽  
Global Criterion ◽  
Terminal Voltage ◽  
System Stabilizer ◽  
Weighting Coefficients ◽  
Parameter Values

Use of Pareto optimisation for tuning power system stabilizers The paper presents a method for determining sets of Pareto optimal solutions (compromise sets) - parameter values of PSS3B system stabilizers working in a multi-machine power system - when optimising different multidimensional criteria. These criteria are determined for concrete disturbances when taking into account transient waveforms of the instantaneous power, angular speed and terminal voltage of generators in one, chosen generating unit or in all units of the system analysed. The application of multi-criteria methods allows taking into account the optimisation process of power system stabilizer (PSS) parameters, many sometimes contradictory requirements (criteria) without losing ability to reach the optimal solution. A choice of the compromise solution can be made by assuming the values of the weighting coefficients associated with particular components of the vector criterion and determining the equivalent, global criterion. A change of the values of those weighting coefficients in the equivalent criterion does not require, in the case of the Pareto optimization, carrying out repeated calculations.

Fault Diagnosis Method of Mine Motor Based on Support Vector Machine

2019 ◽  
Vol 13 ◽  
Author(s):  
Yan Zhang ◽  
Ren Sheng
Keyword(s):  
Support Vector Machine ◽  
Fault Diagnosis ◽  
Optimization Method ◽  
Support Vector ◽  
Optimal Parameters ◽  
Instantaneous Power ◽  
Practical Usefulness ◽  
Sample Data ◽  
Diagnosis Method ◽  
Fault Characteristic

Background: In order to improve the efficiency of fault treatment of mining motor, the method of model construction is used to construct the type of kernel function based on the principle of vector machine classification and the optimization method of parameters. Methodology: One-to-many algorithm is used to establish two kinds of support vector machine models for fault diagnosis of motor rotor of crusher. One of them is to obtain the optimal parameters C and g based on the input samples of the instantaneous power fault characteristic data of some motor rotors which have not been processed by rough sets. Patents on machine learning have also shows their practical usefulness in the selction of the feature for fault detection. Results: The results show that the instantaneous power fault feature extracted from the rotor of the crusher motor is obtained by the cross validation method of grid search k-weights (where k is 3) and the final data of the applied Gauss radial basis penalty parameter C and the nuclear parameter g are obtained. Conclusion: The model established by the optimal parameters is used to classify and diagnose the sample of instantaneous power fault characteristic measurement of motor rotor. Therefore, the classification accuracy of the sample data processed by rough set is higher.

Electrical Properties of Electrospun Nanofibers of PEO/Carbon Black Composite

2009 ◽  
Vol 151 ◽  
pp. 67-71 ◽  
Author(s):  
Wai Kit Li ◽  
Y.W. Wong
Keyword(s):  
Electrical Properties ◽  
Carbon Black ◽  
Polyethylene Oxide ◽  
Electrospun Nanofibers ◽  
Angular Speed ◽  
Polymer Fibers ◽  
Fiber Direction ◽  
Fiber Morphology ◽  
Polarized Ftir ◽  
Specific Orientation

Electrospinning is an efficient technique for the fabrication of polymer nanofibers. The charges inside the polymer jet tend to repel each other so as to stretch and reduce the diameter of the polymer fibers. By rotating the collector at a fast angular speed, nanofibers with specific orientation can be obtained. In this study, nanofibers of Polyethylene oxide (PEO) with carbon black were prepared by electrospinning. PEO was dissolved in a mixture of water and ethanol. PEO is known as an electrolytic polymer. With the blending of carbon black powders, its electrical properties along the fiber direction were investigated. The fiber morphology and characteristics were studied by SEM and polarized FTIR.

scholarly journals Spread of Entanglement in Non-Relativistic Theories

2018 ◽  
Vol 2018 ◽  
pp. 1-27
Author(s):  
Sagar F. Lokhande
Keyword(s):  
Broad Class ◽  
Entanglement Entropy ◽  
Time Dependent ◽  
Quantum Field Theories ◽  
Strongly Coupled ◽  
Conformal Field ◽  
Instantaneous Power ◽  
Holographic Entanglement Entropy ◽  
Quantum Quenches ◽  
Good Order

We use a simple holographic toy model to study global quantum quenches in strongly coupled, hyperscaling-violating-Lifshitz quantum field theories using entanglement entropy as a probe. Generalizing our conformal field theory results, we show that the holographic entanglement entropy of small subsystems can be written as a simple linear response relation. We use this relation to derive a time-dependent first law of entanglement entropy. In general, this law has a time-dependent term resembling relative entropy which we propose as a good order parameter to characterize out-of-equilibrium states in the post-quench evolution. We use these tools to study a broad class of quantum quenches in detail: instantaneous, power law, and periodic.

ON THE HYBRID-DRIVEN LINKAGE MECHANISM WITH ONE INPUT CYCLE CORRESPONDING TO TWO OUTPUT CYCLES

2015 ◽  
Vol 39 (3) ◽  
pp. 637-646
Author(s):  
Ren-Chung Soong
Keyword(s):  
Kinematic Analysis ◽  
Angular Speed ◽  
Motion Trajectory ◽  
Dimensional Synthesis ◽  
Reciprocating Motion ◽  
Linkage Mechanism ◽  
Output Link ◽  
Input And Output ◽  
Single Input ◽  
Selection Of

A hybrid-driven five-bar linkage mechanism with one input cycle corresponding to two output cycles is presented. The proposed linkage mechanism is driven by a constant-speed motor and a linear motor, respectively. The output link can generate two same required output cycles during a single input cycle, while the rotational input link rotates with a constant angular speed, and the linear input link follows a reciprocating motion along a specified linear guide fixed on the rotational input link. The configuration, displacement relationship between the input and output links, and conditions of mobility of this proposed mechanism were studied, and a kinematic analysis was performed. The selection of the instantaneous motion trajectory of the linear input link and an optimal dimensional synthesis are also described. An example is provided to verify the feasibility and effectiveness of this methodology.

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