检索结果-内蒙古大学图书馆

The State Monitoring Method of Electronic Voltage Transformer Based on L-M Algorithm

JOURNAL OF ADVANCED COMPUTATIONAL INTELLIGENCE AND INTELLIGENT INFORMATICS 2019年第3期23卷 385-389页

作者： Lian, Han Henan Polytech Inst Sch Elect Informat Engn Nanyang 473009 Henan Peoples R China

In the traditional method of monitoring the state of electronic voltage transformer, there are problems of large monitoring error and weak robustness. Therefore, a new state monitoring method of electronic voltage transformer based on L-M algorithm is proposed. The relationship between input voltage and output voltage of capacitor voltage divider in electronic voltage transformer is obtained by using Laplasse transform. The transfer function model of electronic voltage transformer is constructed based on the relationship result and L-M algorithm. The transfer function model is used to analyze the frequency characteristics of the electronic voltage transformer and the range of normal measurement frequency, and then the partial pressure ratio of the electronic voltage transformer under the high frequency condition is derived. On this basis, by calculating the over voltage amplitude on the two sides of acquisition card in the electronic voltage transformer, the capacitance value between the two adjacent coaxial cylindrical cylinders of the capacitance divider in the electronic voltage transformer is obtained, thus the monitoring of the state of the electronic voltage transformer is completed. The experimental results show that the proposed method has low detection error and strong robustness, and can effectively improve the reliability of electronic voltage transformer.

关键词： L-M algorithm electronic voltage transformer transfer function model overvoltage amplitude degenerative feedback

来源：评论

学校读者我要写书评

暂无评论

Study on the second-order transfer function models for dynamic tests of flat-plate solar collectors Part I: A proposed new model and a fitting methodology

引用

SOLAR ENERGY 2015年第Apr.期114卷 418-426页

作者： Deng, Jie Yang, Xudong Wang, Pengsu Tsinghua Univ Dept Bldg Sci Beijing 100084 Peoples R China Chinese Acad Sci Inst Elect Engn Key Lab Solar Thermal Energy & Photovolta Syst Beijing 100190 Peoples R China

The existing second-order transfer function models (TFMs) for solar collector dynamic tests are reviewed in light of the heat transfer principles, their inherent relationship, and limitations. Then, another form of TFM in terms of the collector heat removal factor F-R is put forward in this study. And the equivalent relationships among different forms of TFMs are elucidated. Strict error analysis and the weighed least square (WLS) method are used to construct model coefficients in the TFMs due to random measurement errors of data points in dynamic tests. Accuracy levels of the three TFMs will be validated with experimental data in the companion paper (Deng et al., 2015). (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Flat plate solar collector Dynamic thermal performance transfer function model

来源：评论

学校读者我要写书评

暂无评论

A Data-driven Approach to Grid Impedance Identification for Impedance-based Stability Analysis under Different Frequency Ranges

A Data-driven Approach to Grid Impedance Identification for ...

引用

IEEE Milan PowerTech Conference

作者： Li, Chendan Molinas, Marta Fosso, Olav Bjarte Qin, Nan Zhu, Lin Norwegian Univ Sci & Technol NTNU Dept Elect Power Engn Trondheim Norway Norwegian Univ Sci & Technol NTNU Dept Engn Cybernet Trondheim Norway Energinet Dk Fredericia Denmark Univ Tennessee Dept Elect Engn & Comp Sci Knoxville TN USA

ISBN: (纸本)9781538647226

The instability caused by inappropriate damping design of grid-connected converters under specific grid impedance makes the grid impedance estimation a crucial issue. To guide the system controller design toward a stable and adaptive system under various operating conditions, a three-stage data-driven approach for grid impedance identification with three different frequency ranges is proposed by taking advantage of massive data coming from measurement and/or simulation. In the case study, Monte-Carlo simulation is adopted for obtaining the grid impedance data under different operating conditions. K-means clustering is used to partition the processed impedance data, and a high order grid impedance model is generated for each frequency range, in accordance with the practice of resonance mitigation design. The estimation results show that with this approach, the grid model in different frequency ranges can be reduced without losing accuracy while having the potential of being more accurate for impedance-based stability analysis.

关键词： data-driven grid impedance data Monte-Carlo simulation identification K-means clustering transfer function model impedance-based stability

来源：评论

学校读者我要写书评

暂无评论

Oscillation Damping Controller Design Using Ring-down Measurements for the Italian Power Grid

Oscillation Damping Controller Design Using Ring-down Measur...

引用

IEEE Milan PowerTech Conference

作者： Zhu, Lin Zhao, Yi Liu, Yilu Farantatos, Evangelos Patel, Mahendra Dattaray, Papiya Ramasubramanian, Deepak Michi, Luigi Carlini, Enrico Giannuzzi, Giorgio Zaottini, Roberto Univ Tennessee Knoxville TN 37996 USA Oak Ridge Natl Lab Oak Ridge TN USA Elect Power Res Inst EPRI Palo Alto CA USA Terna Rome Italy

ISBN: (纸本)9781538647226

This paper presents the design and demonstration through simulations of a wide-area oscillations damping controller (WADC) for the Italian grid. A simple, linear transfer function model is built using collected ring-down measurements to capture the system's oscillatory behavior. This constructed transfer function model is utilized for the controller design, instead of a complicated dynamic grid model. A tneasurement-driven approach is used to tune the parameters of the controller, thus the transfer function model can be updated online to track the variations of the system operating condition. The proposed approach is validated through a case study on the Italian power grid. The optimal observation signal for the controller is selected using Fast Fourier Transform (FFT) analysis of ring-down measurements. Two Compensation Devices (CDs) are selected as the actuators for the WADC. The control effect of the designed controller is shown for an actual undamped oscillation event that took place in December 2017.

关键词： Low-frequency oscillations Wide-area damping controller Ring-down measurements System identification transfer function model

来源：评论

学校读者我要写书评

暂无评论

Study on the second-order transfer function models for dynamic tests of flat-plate solar collectors Part II: Experimental validation

引用

SOLAR ENERGY 2017年 141卷 334-346页

作者： Deng, Jie Yang, Xudong Wang, Pengsu Tsinghua Univ Dept Bldg Sci Beijing 100084 Peoples R China Chinese Acad Sci Key Lab Solar Thermal Energy & Photovolta Syst Inst Elect Engn Beijing 100190 Peoples R China

In order to validate the accuracy levels of three forms of transfer function models (TFMs), dynamic thermal performance tests of a flat-plate solar air collector with louvered fin structure are conducted. model coefficients in the TFMs are constructed by strict error analysis and the weighed least square (WLS) method. Comparing with the experimental data, it is verified that the three forms of TFMs perform well and have the similar level of accuracy. It is further demonstrated that, the second-order differential TFMs have the same accuracy as the reduced first-order differential models with the present temperature measurement accuracy using thermocouples. Whilst the collector thermal storage quantities of the second-order differential terms in the TFMs are very small. In order for the second-order TFMs to perform better in the dynamic tests, the measured accuracy of temperatures should be improved. Otherwise, the combined standard uncertainties of the second-order differential terms of temperatures could be larger than the second-order differential terms of temperatures and the second-order terms in the three forms of TFMs would become meaningless. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Flat plate solar collector Dynamic thermal performance transfer function model

来源：评论

学校读者我要写书评

暂无评论

System identification black box approach for modeling performance of PEM fuel cell

引用

JOURNAL OF ENERGY STORAGE 2018年第Aug.期18卷 327-332页

作者： Chavan, Sudarshan L. Talange, Dhananjay B. Coll Engn COEP Dept Elect Engn Pune Maharashtra India

A polymer electrolyte membrane (PEM) fuel cell is very useful for distributed generation and for portable users like electric vehicles because it is very efficient, emission free and operated at low temperature. However, it is not so easy to find direct experimental estimates of the actual performance of PEM fuel cell through various phenomena and operating conditions like chemical reactions, fuel pressure, working temperature and fuel humidity. Mathematical modeling, therefore, plays an important role in understanding operational performance of PEM fuel cell. The actual operating performance of PEM fuel cell depends on a number of parameters, therefore developing an accurate model that includes its dynamic behavior is most important. In this paper, first time, the system identification black box approach is used to develop a number of simple but more realistic mathematical model structures for a PEM fuel cell. The performance of each model structure is compared with the data from a 25 cm(2) active area practical PEM fuel cell for result validation. The presented models can be used to predict polarization behavior of the PEM fuel cell under different loading conditions.

关键词： PEM fuel cell System identification transfer function model State space model Autoregressive model

来源：评论

学校读者我要写书评

暂无评论

transfer function Analysis: modelling Residential Building Costs in New Zealand by Including the Influences of House Price and Work Volume

引用

BUILDINGS 2019年第6期9卷 152页

作者： Zhao, Linlin Mbachu, Jasper Liu, Zhansheng Zhang, Huirong Beijing Univ Technol Coll Architecture & Civil Engn Beijing 100091 Peoples R China Bond Univ Fac Soc & Design Gold Coast 4226 Australia

An accurate cost estimate not only plays a key role in project feasibility studies but also in achieving a final successful outcome. Conventionally, estimating cost typically relies on the experience of professionals and cost data from previous projects. However, this process is complex and time-consuming, and it is challenging to ensure the accuracy of the estimates. In this study, the bivariate and multivariate transfer function models were adopted to estimate and forecast the building costs of two types of residential buildings in New Zealand: Low-rise buildings and high-rise buildings. The transfer function method takes advantage of the merits of univariate time series analysis and the power of explanatory variables. In the dynamic project conduction environment, simply including building cost data in the cost forecasting models is not valid for making predictions, because the change in demand must be considered. Thus, the time series of house prices and work volume were used to explain exogenous effects in the transfer function model. To demonstrate the effectiveness of transfer function models, this study compared the results generated by the transfer function models with autoregressive integrated moving average models. According to the forecasting performance of the models, the proposed approach achieved better results than autoregressive integrated moving average models. The proposed method can provide accurate cost estimates that can help stakeholders in project budget planning and management strategy making at the early stage of a project.

关键词： ARIMA transfer function model time series analysis short-term forecasts residential building costs

来源：评论

学校读者我要写书评

暂无评论

Frequency-coupled impedance model based subsynchronous oscillation analysis for direct-drive wind turbines connected to a weak AC power system

引用

JOURNAL OF ENGINEERING-JOE 2019年第18期2019卷 4841-4846页

作者： Liu, Wei Xie, Xiaorong Shair, Jan He, Jingbo Tsinghua Univ Dept Elect Engn State Key Lab Power Syst Beijing Peoples R China Natl Power Dispatching & Control Ctr Beijing Peoples R China

Recently, the emerging subsynchronous oscillation (SSO) issue caused by interactions between power electronic converters and weak grids has provoked serious stability concerns. Impedance modelling based method has been widely used to analyse the emerging SSO phenomenon. In this paper, a frequency coupled impedance model (FCIM) is proposed to analyse this interaction. The FCIMs at multiple frequencies are measured and then the transfer function model is identified. The modelling method is then applied to type-4 wind turbine based farms connected to a weak AC grid. The aggregated impedance of the whole system is obtained by combining the FCIMs of all components in the power system. The system stability is then investigated by varying the online number of wind turbines. Time-domain simulations using PSCAD/EMTDC are carried out to verify the proposed methods of impedance modelling and stability analysis.

关键词： wind power plants transfer functions oscillations power grids power generation faults time-domain analysis power electronics wind turbines aggregated impedance system stability stability analysis frequency-coupled impedance model subsynchronous oscillation analysis direct-drive wind turbines weak AC power system emerging subsynchronous oscillation issue power electronic converters weak grids serious stability concerns impedance modelling based method emerging SSO phenomenon frequency coupled impedance model FCIM multiple frequencies transfer function model modelling method type-4 wind turbine weak AC grid

来源：评论

学校读者我要写书评

暂无评论

PID controller design for load frequency control: Past, Present and future challenges

引用

IFAC-PapersOnLine 2018年第4期51卷 604-609页

作者： Hote, Yogesh V. Jain, Shivam Indian Institute of Technology RoorkeeUttarakhand247667 India

In this paper, a brief literature review for the design of a PID controller for load frequency control (LFC) in power systems is presented. The transfer function models for various configurations of power systems are developed. For a systematic presentation of the review, the PID tuning schemes are categorised into soft computing techniques, robust control schemes, fractional order based PID design and internal model control (IMC) based PID design approaches. Due diligence has been taken to include all the design schemes. Further, the paper also enlists various future challenges that are still unresolved and can form the basis of future research work. © 2018

关键词： Electric control equipment Controllers Disturbance rejection Electric frequency control Electric load management Mathematical models model predictive control Press load control Proportional control systems Robust control Soft computing Three term control systems Fractional order pid Internal model control Load frequency control (LFC) Load frequency control PID controller design Robust control scheme Softcomputing techniques transfer function model

来源：评论

学校读者我要写书评

暂无评论

The Effect of Prior Knowledge on the Least Costly Identification Experiment⁎

引用

IFAC-PapersOnLine 2018年第15期51卷 209-214页

作者： Birpoutsoukis, Georgios Bombois, Xavier Department of ELEC Vrije Universiteit Brussel Pleinlaan 2 Brussel1050 Belgium Laboratoire Ampère UMR CNRS 5005 Ecole Centrale de Lyon Ecully69134 France

Design of optimal input excitations is one of the most challenging problems in the field of system identification. The main difficulty lies in the fact that the optimization problem cannot always be formulated to be convex, therefore a globally optimal excitation for the dynamic system of interest cannot be guaranteed. In this paper, optimal input design (OID) for linear systems in the presence of prior knowledge is studied. Information related to exponential decay and smoothness is incorporated in the optimal input design problem by making use of the Bayes rule of information. Three different cases of modeling the linear dynamics are considered, namely Finite Impulse Response (FIR) model with and without prior knowledge, as well as the rational transfer function case. It is shown that the prior information affects the spectrum of the minimum power optimal input. The input with the least power is always obtained for the transfer function model case. © 2018

关键词： transfer functions Identification (control systems) Impulse response Linear systems Rational functions Religious buildings Exponential decays Finite impulse responses (FIR) Optimal experiment design Optimal input design Optimization problems Rational transfer functions Regularization transfer function model

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：