On-Line Evaluation of Voltage Transformer Accuracy

2012 ◽  
Vol 433-440 ◽  
pp. 6071-6076 ◽  
Author(s):  
Xiao Hui Yang ◽  
Dong Yan ◽  
Kai Xie ◽  
Yong Wang
Keyword(s):  
Evaluation System ◽  
Current Transformer ◽  
Test Results ◽  
Voltage Transformer ◽  
Ratio Error ◽  
Key Factor ◽  
On Line ◽  
Power Metering ◽  
Site Test ◽  
Key Techniques

The accuracy of voltage and current transformer (VT and CT) is a key factor in electric power metering. Ratio error and phase displacement calibration of VT and CT is traditionally carried out off-line. As a result of the expansion of the power grid and the increasing metering quality requirements from customer side, the off-line metering of VT and CT becomes more and more difficult. In this paper, a VT accuracy on-line evaluation system is developed, which can evaluate the accuracy of VT under on-line operating status. The principle and adopted key techniques in the development of the VT accuracy on-line evaluation system is introduced. Some on-site test results are also presented and analyzed as application demonstration.

The Current Transformer Accuracy On-Line Evaluation System

2012 ◽  
Vol 433-440 ◽  
pp. 6880-6885
Author(s):  
Dong Yan ◽  
Kai Xie ◽  
Yong Wang ◽  
Xiao Hui Yang ◽  
Fei Ma ◽  
...  
Keyword(s):  
Evaluation System ◽  
Current Transformer ◽  
Power Lines ◽  
Accuracy Evaluation ◽  
Ratio Error ◽  
System Protection ◽  
Standard Part ◽  
On Line ◽  
Line Test ◽  
Monitoring And Measurement

The accuracy of current transformer (CT) is important guarantee of power system protection, monitoring and measurement. A new method based on live working technique for CT accuracy evaluation is proposed in this paper. Through constructing standard part, which is on-line insert into power lines, and comparing the data of standard part with the data of the measured part, the system can calculate the ratio error and phase displacement of the measured CT. The results of on-line test have shown that the proposed method is feasible and effective, and the accuracy of proposed system achieves 0.1 grades.

Simulation and Analysis for Current Transformers with DC Bias and Remnant Flux

2013 ◽  
Vol 765-767 ◽  
pp. 2430-2434
Author(s):  
Xiao Qian Tian ◽  
Bao Shu Li ◽  
Lu Shen
Keyword(s):  
Error Compensation ◽  
Current Transformer ◽  
Scientific Basis ◽  
Current Transformers ◽  
Ratio Error ◽  
Full Wave ◽  
Accuracy Of Measurement ◽  
Dc Bias ◽  
Power Metering ◽  
Fourier Algorithm

The transfer characteristics of current transformers (CT) change due to DC bias, which directly impacts the accuracy of measurement and power metering. Based on equivalent circuit models and core magnetizing characteristic, qualitatively analysis current transformer saturation increase errors of CT. Transfer errors under DC bias and remnant flux are also obtained based on J-A model of CT in PSCAD/EMTDC and full-wave Fourier algorithm to show that the ratio error and phase displacement increase with the DC bias. Based on FFT spectrum analysis to identify remnant flux and DC bias provides scientific basis for error compensation of CT.

Research on Three-Phase Calibration Method of HV Three-Phase Combined Transformer and its Implementation

2014 ◽  
Vol 568-570 ◽  
pp. 1191-1195 ◽  
Author(s):  
Hua Yun Yang
Keyword(s):  
Mutual Influence ◽  
Calibration Method ◽  
Current Transformer ◽  
Test Results ◽  
Error Performance ◽  
Voltage Transformer ◽  
Test Circuit ◽  
Three Phase ◽  
Phase Calibration ◽  
Working Principle

In this paper, a three-phase calibration method which is that the three-phase voltage transformer or current transformer of HV three-phase combined transformer is calibrated in the same time with simulating real running state is proposed. And a standard calibrating apparatus which is used to implementation three-phase calibration method is designed. The structure, working principle, technical characteristics, test circuit and test results of standard calibrating apparatus are given out. The large test results show that the error performance in real running state of 10kV-35kV HV three-phase combined transformer can be calibrated accurately and the error caused by the mutual influence between the voltage transformer or current transformer can be detected out with the proposed three-phase calibration method and apparatus.

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

scholarly journals Local Government Competition and Regional Green Development in China: The Mediating Role of Environmental Regulation

2020 ◽  
Vol 17 (10) ◽  
pp. 3485 ◽  
Author(s):  
Na Zhang ◽  
Jinqian Deng ◽  
Fayyaz Ahmad ◽  
Muhammad Umar Draz
Keyword(s):  
Local Government ◽  
Environmental Regulation ◽  
Regional Differences ◽  
Evaluation System ◽  
Measure Data ◽  
Scale Efficiency ◽  
Fiscal Competition ◽  
Green Development ◽  
Key Factor ◽  
Investment Competition

Green development is an important way to meet the challenges of ecological and environmental protection and economic growth, as well as an inevitable choice to realize China’s sustainable development in the new era. The Chinese economic system is such that local government competition has become a key factor affecting regional green development under the current leadership. Based on the inter-provincial panel data of 30 provinces in mainland China from 1997 to 2017, this paper uses the total-factor non-radial directional distance function and slack-based measure data envelopment analysis (SBM-DEA) to measure the green development efficiency of the provinces. Additionally, it also uses the Malmquist–Luenberger (ML) index to decompose green development efficiency and analyzes its internal driving factors. Finally, taking environmental regulation as a mediating variable, this paper empirically analyzes the influence mechanism of local government competition on green development efficiency from three perspectives including growth competition, fiscal competition and investment competition. The study found that: the green development efficiency of Chinese regions showed a downward trend, with significant regional differences; technological progress is the key factor to improve the efficiency of green development, and its role gradually decreases from eastern to western and central regions; pure technical efficiency has become a bottleneck restricting the improvement of green development efficiency, while scale efficiency shows significant regional differences; the growth competition, fiscal competition and investment competition of local government all have a significant inhibitory effect on the efficiency of green development. This paper puts forward policy suggestions supporting enterprise technology research and development, optimizing energy conservation and emission reduction as well as improving the local government performance evaluation system for green development.

Web design skills and competencies: an empirical analysis

2002 ◽  
Vol 21 (2) ◽  
pp. 115-128
Author(s):  
Francesca Sgobbi
Keyword(s):  
Information And Communication Technologies ◽  
Web Design ◽  
Communication Technologies ◽  
Knowledge Domains ◽  
Skill Gaps ◽  
Key Factor ◽  
Fast Pace ◽  
Information And Communication ◽  
On Line ◽  
Design Skills

The availability of proper human capital represents a key-factor in order to support the current fast pace of diffusion of Internet-based applications. The careful assessment of the skills and competencies required to manage and develop Internet technologies in different application domains represents a necessary step to solve the emerging skill shortage and skill gap problems. While most existing analyses of skill needs in information and communication technologies deal with broad professional categories, the paper focuses the attention on a specific professional figure, the Web designer. By resorting to an on-line questionnaire administered to a sample of Italian Web designers, the paper shows that jobholders recognise greater usefulness to organisational rather than technical knowledge domains. However, perceived skill gaps are larger in the case of technical skills and competencies. Moreover, specialisation paths are emerging.

Design and optimization for current transformer core based on magnetic field analysis

2021 ◽  
pp. 1-14
Author(s):  
Guoyong Zhang ◽  
Jing Luo ◽  
Lifu He ◽  
Xiudong Zhou ◽  
Shaosheng Fan
Keyword(s):  
Transmission Lines ◽  
Great Influence ◽  
Current Transformer ◽  
Magnetic Core ◽  
Field Analysis ◽  
Core Material ◽  
Design And Optimization ◽  
Magnetic Field Analysis ◽  
Acquisition Device ◽  
On Line

In order to ensure the safety and reliability of power system, more and more monitoring and maintenance equipment on transmission lines are being used. However, these equipment would not work without the supply of power. At present, the current transformer has been widely used in the on line power acquisition device. As an important part of the current transformer, the performance magnetic core has great influence on the power acquisition. In this paper, the core parameters of the current transformer in the on-line power acquisition device are designed, and the parameters such as core material and air gap length are optimized and verified by simulation as well.

scholarly journals The Study of Interoperability Test for Onboard Control System in Railway Condition

2011 ◽  
Vol 2-3 ◽  
pp. 785-790
Author(s):  
Jong Hyen Baek ◽  
Yong Kyu Kim ◽  
Jae Ho Lee ◽  
Hyen Jung Jo
Keyword(s):  
Control System ◽  
Control Systems ◽  
Data Systems ◽  
Test Results ◽  
Simulation Environment ◽  
Train Control ◽  
Interoperability Test ◽  
Critical Characteristics ◽  
Site Test ◽  
Onboard Equipment

For the purpose of improving the future domestic train control systems and securing interoperability, according to the global development trends of train control systems, it is presented that the test results of interoperability between wayside train control systems installed in existed line, and the onboard train control system. Due to the safety-critical characteristics of train systems, the site test in the section where the wayside equipment is installed may lead to a danger against safety. Therefore, by way of constructing a simulation environment of train control systems, the T/R data systems of the equipment for interoperability are confirmed and the interoperability test are obtained by applying these systems to onboard equipment.

Development of On-Line Monitoring System and Aging Characteristics Research of Switchgear

2013 ◽  
Vol 330 ◽  
pp. 364-367
Author(s):  
Shu Xin Liu ◽  
Yun Dong Cao ◽  
Chun Guang Hou ◽  
Yang Liu ◽  
Xiao Ming Liu
Keyword(s):  
Epoxy Resin ◽  
Monitoring System ◽  
Estimation Method ◽  
Current Transformer ◽  
Insulation Material ◽  
Electrical Characteristics ◽  
Infrared Transmission ◽  
Lifetime Estimation ◽  
Monitoring Method ◽  
On Line

For improving reliable operation of switchgear in power system, an approach for on-line monitoring the insulation characteristic and bus-bar temperature rising of the switchgear is proposed in this paper. Through comparing several existing temperature measurement methods for monitoring temperature rising elevation at bus-bas, a new design of temperature monitoring method is proposed. It adopts quick-magnetic saturated current transformer, temperature sensor and infrared transmission to solve the problem of high voltage isolation. The epoxy resin insulation material which is commonly used in switchgear its aging mechanism data is not complete, seriously restrict on-line monitoring for switchgear, so thousands hours of aging experiment is done on switchgear, systematic study various electrical characteristics variation law on the gradual aging process of epoxy resin insulation materials. Therefore, study on the aging characteristics of switchgearinsulation and its lifetime estimation method is the key technology to understand agingmechanism better, search for new fault diagnostic method and the way to extend theuseful lifetime of switchgear. At last, the system runs in real system and the result shows the on-line monitoring system is stable and reliable which can be provide reference for on-line monitoring system design of switchgear.

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