Dynamic Equivalent Modeling for Black-box Microgrids Under Multi-operating-point by Using LSTM

Since the high penetration of distributed energy sources complicates the dynamics of electrical power systems,accurate dynamic models are indispensable for study on the transient behavior of the microgrid(MG).In some practices,the lack of full detailed information results in failure of dif-ferential equation based dynamic modeling,which leads to a demand for a black-box MG modeling method.It is a critical challenge to maintain the effectiveness of the black-box model under a wide operating range and various fault conditions.In this paper,inspired by the mathematical equivalence between the recurrent neural network(RNN)and differential-algebraic equations(DAEs),a dynamic equivalent modeling method,using long short-term memory(LSTM),is presented to tackle this challenge.At first,the modeling equivalence and advantages of our basic idea are explained.Then,modeling procedures,including data preparation and design guidelines,are presented.Finally,the proposed method is applied to a multi-microgrid testing system for performance evaluation.The results,under various scenarios,reveal that the proposed modeling method has an adequate capability for representing the dynamic behaviors of a black-box MG under grid fault and operating point changing conditions.Index Terms-Deep learning,dynamic behavior,dynamic equivalent model,microgrid,neural network.

Applying the Principle of Dynamic Equivalence in the Translation of the Heading of News Report

Nida's famous notion of Dynamic Equivalence in translation process is characterized by three stages - analysis, transfer and restructuring, which are explained in detail. The application of these principles are illustrated by providing step-by-step explanation on the translation process of headings of two news reports, which are selected from Far Eastern Economic Review.

Sub-synchronous frequency domain-equivalent modeling for wind farms based on rotor equivalent resistance characteristics

The equivalent simplification of large wind farms is essential for evaluating the safety of power systems.However,sub-synchronous oscillations can significantly affect the stability of power systems.Although detailed mathematical models of wind farms can help accurately analyze the oscillation mechanism,the solution process is complicated and may lead to problems such as the“dimensional disaster.”Therefore,this paper proposes a sub-synchronous frequency domain-equivalent modeling method for wind farms based on the nature of the equivalent resistance of the rotor,in order to analyze sub-synchronous oscillations accurately.To this end,Matlab/Simulink is used to simulate a detailed model,a single-unit model,and an equivalent model,considering a wind farm as an example.A simulation analysis is then performed under the sub-synchronous frequency to prove that the model is effective and that the wind farm equivalence model method is valid.

The Application of Dynamic Equivalence in the English Translation of Chinese Idioms

Chinese idioms are hard to translate.The aim of this thesis is to analyze Nida's Dynamic Equivalence and apply it to the translation of Chinese idioms.

An Analysis of the Three Translated Versions of Youth from the Perspective of Dynamic Equivalence

Inspired by Eugene Nida's dynamic equivalence theory,this thesis takes the translation of Samul Ullman's work Youth as a case study.It explores the three translated versions of Mrs.Zhang Aiqing,Mr.Huang Ren and Mr.Xu Hanlin respectively.These versions are analyzed at the levels of lexicology,syntax,rhetoric,semasiology and style.Then it points out that the same effect on the target language readers are as the original text has done on the source language readers,in other words,it proves the efficiency of dynamic equivalence in the translation of Youth.

The Application of Dynamic Equivalence and its Limitations in Translation for Poetry

This essay explores the notion of dynamic equivalence proposed by Nida and its practical usage as well as limitations in translation for poetry,and all the examples are drawn from the Story of the Stone,translated by David Hawkes from Chinese into English.

Analysis of the Features of Children's Picture Book and Discussing the Possible Strategies of Translating Children's Picture Story Book from English to Chinese

Translation of children's literature has developed so quickly in recent years that many scholars have turned to research it. However, as special readers, children's reading ability are limited. This thesis analyzes and discusses the features of children's book and the possible strategies on translation of children's book.

From Equivalence to Skopos: A Theoretical "Dialogue" between Nida and the Functional School

Dynamic Equivalence and Skopos Theory are two important translation theories in the fields of translation, which many scholars spare no efforts to research on. This short essay intends to compare and complement between Nida's Dynamic Equivalence and Skopos theory after briefly reviewing these two translation theories. It is aimed for helping readers improve their translation skills via stimulating them to consider translation issues from different angles, such as the nature of translation, the target of translation, translation market, cultural constrains, translation process, translation effects, and etc. And this essay focuses on Nida's Dynamic Equivalence and Skopos theory, a part of functional theories via comparing and harmonizing these two translation theories.

The Analysis of “Feng Qiao Ye Bo” on the Basis of Nida's Translation Theory

"Feng Qiao Ye Bo" has been translated into many different English versions,a systematic translation analysis using Nida's two types of equivalence-formal equivalence and dynamic equivalence-has not been undertaken.This thesis thus aims at translating " Feng Qiao Ye Bo" by using two important translation theories of Nida and trys to search for their differences.

A General Model for Analysis of Sound Radiation from Orthogonally Stiffened Laminated Composite Plates

A general theoretical model is developed to investigate the sound radiation from an infinite orthogonally stiffened plate under point excitation force. The plate can be metallic or composite, and fluid loading is also considered in the research. The first order shear deformation theory is used to account for the transverse shear deformation. The motion of the equally spaced stiffeners is examined by considering their bending vibrations and torsional movements. Based on the periodic structure theory and the concepts of the equivalent dynamic flexibility of the plate, the generalized vibro-acoustic equation of the model is obtained by applying the Fourier transform method. The generalized model that can be solved numerically is validated by comparing model predictions with the existing results. Numerical calculations are performed to investigate the effects of the location of the excitation, the spacing of the stiffeners, the plate thickness, the strengthening form and the fiber orientation on the sound radiation characteristic of the orthogonaUy stiffened plate, and some practical conclusions are drawn from these parameter studies.

Ways to Translate a Newly-Introduced Concept

Translation is a complicated thinking and a practicing process,which involves many theories and skills.According to the theory of dynamic equivalence and based on literature studies as well as personal practical experiences,three viewpoints have been proposed in this article to discuss on how to translate a newly-introduced concept;namely,giving full consideration to the meaning of newly-introduced concepts,paying attention to the evolution of the concepts,and seeking for a similar meaning in the traditional classics of a nation,each of which is exemplified in order to facilitate understanding.

Discussion on Nida's Translation Theory and Applications Through MuLAN

Eugene Nida's Translation Theory has a profound influence both on global and Chinese translation circle.Although this theory is widely used,it also become a controversial topic in a certain extent.Through the movie MuLAN and some applications in useful areas to discuss whether Nida's Translation Theory is still applicable within translating field.

Comments on Eugene A. Nida＇s Translation Theory

This paper attempts to illustrate Nida's Dynamic Equivalence in translation from culture. Because of different cultural and historical settings, it's not easy to achieve absolute equivalent in translation. As a translator, one should have the knowledge of both the source language and the receptor language. Meanwhile one should respect different customs and traditions so as to provide a better version for the readers.

From Equivalence to Skopos:A Theoretical"Dialogue"between Nida and the Functional School

The aim of this essay is to analyze the theories of translation raised by Eugene Nida and the Functional School respectively.The focus is on the Dynamic Equivalence and Skopos Theory.This essay introduces the characteristics and deficiencies of the two theories and compares the differences between them.

Dynamic analysis of C/C composite finger seal

A seal device as an important component of aeroengines has decisive influence on per- formance, reliability, and working life of aeroengines. With the development of aeroengines, demands on the performance characteristics of seal devices are made strictly. Finger seal as a novel kind of sealing device, recently attracts more and more attentions in academic circles and engineer- ing fields at home and abroad. Research on finger seals has been extensively developed, especially on leakage and wear performances under dynamic conditions. However, it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization; in addition, the technology of dynamic analysis on finger seals is weak. Aiming at the problems mentioned above, a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper, the dynamic perfor- mance of 2.5 dimension C/C composite finger seal is analyzed with the model, and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal＇s dynamic performance are discussed, as well as compared with those of Co-based alloy finger seal. The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.

Dynamic Capture Method for Out-of-step Center of Power Grid Based on Measurement Information

This paper dynamically captures the out-of-step center for a bulk power system based on measurement information.First,the position characteristics of the out-of-step center are discussed from the perspective of triangular geometry under different potential and uniform impedance distributions based on a two-machine system.The correlation between the out-of-step center and the oscillation center is analyzed.Second,combined with analytical geometry,it is inferred that the distribution characteristics of the out-of-step center voltage vector ends are a circle or a straight line,and the position of the out-of-step center corresponds to the intersection between the voltage drop of the line and the distribution characteristics;then,the accurate location of the out-of-step center and the determination of the appearance moment is realized.Finally,a dynamic equivalence method for a power grid is proposed based on the electrical parameters of the transmission line,and an alternative iterative correction of equivalent parameters is carried out by trajectory sensitivity,which provides a new way for capturing the out-ofstep center dynamically in a multimachine system.The proposed method is validated using a three-machine system,the IEEE-39 system and the Northwest China Power Grid,and shows potential for online applications.

Sound Transmission Comparisons of Active Elastic Wave Metamaterial Immersed in External Mean Flow

Using the active feedback control system on the elastic wave metamaterial,this research concentrates on the sound transmission with the dynamic effective model.The metamaterial is subjected to an incident pressure and immersed in the external mean flow.The elastic wave metamaterial consists of double plates and the upper and lower four-link mechanisms are attached inside.The vertical resonator is attached by the active feedback control system and connected with two four-link mechanisms.Based on the dynamic equivalent method,the metamaterial is equivalent as a single-layer plate by the dynamic effective parameter.With the coupling between the fluid and structure,the expression of the sound transmission loss(STL)is derived.This research shows the influence of effective mass density on sound transmission properties,and the STL in both modes can be tuned by the acceleration and displacement feedback constants.In addition,the dynamic response and the STL are also changed obviously by different values of structural damping,incident angle(i.e.,the elevation and azimuth angles)and Mach number of the external fluid with the mean flow property.The results for sound transmission by two methods are compared,i.e.,the virtual work principle for double plates and the dynamic equivalent method corresponding to a single one.This paper is expected to be helpful for understanding the sound transmission properties of both pure single-and double-plate models.

PARAMETER ESTIMATION METHODOLOGY FOR NONLINEAR SYSTEMS:APPLICATION TO INDUCTION MOTOR

This paper deals with on-line state and parameter estimation of a reasonably large class of nonlinear continuous-time systems using a step-by-step sliding mode observer approach. The method proposed can also be used for adaptation to parameters that vary with time. The other interesting feature of the method is that it is easily implementable in real-time. The efficiency of this technique is demonstrated via the on-line estimation of the electrical parameters and rotor flux of an induction motor. This application is based on the standard model of the induction motor expressed in rotor coordinates with the stator current and voltage as well as the rotor speed assumed to be measurable. Real-time implementation results are then reported and the ability of the algorithm to rapidly estimate the motor parameters is demonstrated. These results show the robustness of this approach with respect to measurement noise, discretization effects, parameter uncertainties and modeling inaccuracies. Comparisons between the results obtained and those of the classical recursive least square algorithm are also presented. The real-time implementation results show that the proposed algorithm gives better performance than the recursive least square method in terms of the convergence rate and the robustness with respect to measurement noise.