• Title/Summary/Keyword: State Assessment System

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Computer Program Development for Station Reliability Assessment using System State Transition Sampling (시스템상태천이 샘플링을 이용한 변전소 신뢰도평가 컴퓨터 프로그램 개발)

  • Kim, Gwang-Won;Woo, Kyoung-Hang;Hyun, Seung-Ho;Sohn, Jin-Man;Han, Jin-Hee;Shin, Yong-Hark
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.1
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    • pp.104-112
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    • 2008
  • This paper presents the computer program for station reliability assessment. The developed program is based on Monte-Carlo simulation using system state transition sampling, which has the merit of rapid assessment compared to state duration sampling. One of the contributions of this paper is introduction of exclusiveness among events, which makes non-exponential probabilistic distribution be utilized in modeling repair time. The developed program is applied to well-blown sample system, and its assessment results are listed in this paper to show the reliability of the program.

Transmission Network Expansion Planning Using Reliability and Economic Assessment

  • Kim, Wook-Won;Son, Hyun-Il;Kim, Jin-O
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.895-904
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    • 2015
  • This paper presents a probabilistic approach of reliability evaluation and economic assessment for solving transmission network expansion planning problems. Three methods are proposed for TNEP, which are reorganizing the existing power system focused on the buses of interest, selecting candidates using modified system operating state method with healthy, marginal and at-risk states, and finally choosing the optimal alternative using cost-optimization method. TNEP candidates can be selected based on the state reliability such as sufficient and insufficient indices, as proposed in this paper. The process of economic assessment involves the costs of construction, maintenance and operation, congestion, and outage. The case studies are carried out with modified IEEE-24 bus system and Jeju island power system expansion plan in Korea, to verify the proposed methodology.

Online automatic structural health assessment of the Shanghai Tower

  • Zhang, Qilin;Tang, Xiaoxiang;Wu, Jie;Yang, Bin
    • Smart Structures and Systems
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    • v.24 no.3
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    • pp.319-332
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    • 2019
  • Structural health monitoring (SHM) is of great importance to super high-rise buildings. The Shanghai Tower is currently the tallest building in China, and a complete SHM system was simultaneously constructed at the beginning of the construction of the tower. Due to the variety of sensor types and the large number of measurement points in the SHM system, an online automatic structural health assessment method with few computations and no manual intervention is needed. This paper introduces a structural health assessment method for the Shanghai Tower that uses the coefficients of an autoregressive (AR) time series model as structural state indicators. An analysis of collected data indicates that the coefficients of the AR model are affected by environmental factors, and the principal component analysis method is used to remove the influence of environmental factors. Finally, the control chart method is used to track the changes in structural state indicators, and a plan for online automatic structure health state evaluation is proposed. This method is applied to long-term acceleration and inclination data from the Shanghai Tower and successfully identifies the changes in the structural state. Overall, the structural state indicators of the Shanghai Tower are stable, and the structure is in a healthy state.

Reliability Evaluation of Power System Operations Considering Time-Varying Features of Components

  • Hu, Bo;Zheng, Ying;Yang, Hejun;Xia, Yun
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1422-1431
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    • 2015
  • The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.

Development of an Intelligent Power Plant Operating State Monitoring System (발전소 설비 운영상태 지능감시 시스템 개발)

  • Hong, Chang-Ho;Kim, Seok-Hyun;Lee, Seung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.1
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    • pp.38-43
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    • 2012
  • For safe and stable operations of power plants, it is essential to monitor closely crucial measurement values related to power plant trips. In this paper, an intelligent power plant operating state monitoring technique enabling the operating crew member to monitor conveniently the status of the important measurement values and to perceive almost instantly the significance of the implications of those measurement values is developed. The proposed technique is called a "POST(Plant Operating State Tracking) Chart" technique and provides the foundations in developing an intelligent and integrated power plant operating state monitoring support system called the "P-OASIS"(Plant Operation Assessment and Support Intelligent System). The P-OASIS is applied to a thermal power plant of 500[MW] capacity and exhibited impressive performances.

Condition Assessment for Wind Turbines with Doubly Fed Induction Generators Based on SCADA Data

  • Sun, Peng;Li, Jian;Wang, Caisheng;Yan, Yonglong
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.689-700
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    • 2017
  • This paper presents an effective approach for wind turbine (WT) condition assessment based on the data collected from wind farm supervisory control and data acquisition (SCADA) system. Three types of assessment indices are determined based on the monitoring parameters obtained from the SCADA system. Neural Networks (NNs) are used to establish prediction models for the assessment indices that are dependent on environmental conditions such as ambient temperature and wind speed. An abnormal level index (ALI) is defined to quantify the abnormal level of the proposed indices. Prediction errors of the prediction models follow a normal distribution. Thus, the ALIs can be calculated based on the probability density function of normal distribution. For other assessment indices, the ALIs are calculated by the nonparametric estimation based cumulative probability density function. A Back-Propagation NN (BPNN) algorithm is used for the overall WT condition assessment. The inputs to the BPNN are the ALIs of the proposed indices. The network structure and the number of nodes in the hidden layer are carefully chosen when the BPNN model is being trained. The condition assessment method has been used for real 1.5 MW WTs with doubly fed induction generators. Results show that the proposed assessment method could effectively predict the change of operating conditions prior to fault occurrences and provide early alarming of the developing faults of WTs.

An Assessment on Harmonics Effect in Customer and the Distributed Power System during Grid Connection of Residential Fuel Cell System (가정용 연료전지 시스템의 계통연계 시 수용가 및 배전계통에서의 고조파 영향 평가)

  • Park, Chan-Eom;Jung, Jin-Soo;Han, Woon-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1280-1285
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    • 2011
  • Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.

The Development of a Risk Management System in the Field of Industrial Safety in the Republic of Kazakhstan

  • Kudryavtsev, Sergey S.;Yemelin, Pavel V.;Yemelina, Natalya K.
    • Safety and Health at Work
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    • v.9 no.1
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    • pp.30-41
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    • 2018
  • Background: The purpose of the work is to develop a system that allows processing of information for analysis and industrial risk management, to monitor the level of industrial safety and to perform necessary measures aimed at the prevention of accidents, casualties, and development of professional diseases for effective management of industrial safety at hazardous industrial sites. Methods: Risk assessment of accidents and incidents is based on expert evaluations. Based on the lists of criteria parameters and their possible values, provided by the experts, a unified information and analytical database is compiled, which is included in the final interrogation questionnaires. Risk assessment of industrial injuries and occupational diseases is based on statistical methods. Results: The result of the research is the creation of Guidelines for risk management on hazardous industrial sites of the Republic of Kazakhstan. The Guidelines determine the directions and methods of complex assessment of the state of industrial safety and labor protection and they could be applied as methodological basis at the development of preventive measures for emergencies, casualties, and incidents at hazardous industrial sites. Conclusion: Implementation of the information-analytical system of risk level assessment allows to analyze the state of risk of a possible accident at industrial sites, make valid management decisions aimed at the prevention of emergencies, and monitor the effectiveness of accident prevention measures.

Fuzzy Linguistic Variable Based Approach for Safety Assessment of Human Body in ELF Electromagnetic Field Considering Power System States (계통상태를 고려한 ELF 전자계의 인체안전평가를 위한 퍼지언어변수 접근법)

  • 김상철;김두현;고은영
    • Journal of the Korean Society of Safety
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    • v.12 no.2
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    • pp.70-79
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    • 1997
  • This paper presents a study on the fuzzy linguistic variable based approach for safety assessment of human body in ELF electromagnetic field considering power system states. To cope with the demand in modern industry, the power system becomes larger in scale, higher in voltage. The advent of high voltage system has increased the relative importance of field effects. The analysis of ELF electromagnetic field based on Quasi-Static Method is introduced while the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes. In order to analyze the power system, Monte Carlo simulation method and contingency analysis method are adopted in normal state and alert state, respectively. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a sample system(modified IEEE 14 bus system) to validate the usefulness.

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Fuzzy Based Approach for the Safety Assessment of Human Body under ELF EM field Considering Power System States

  • Kim, Sang C.;Kim, Doo H.
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 1997.11a
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    • pp.117-122
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    • 1997
  • This paper presents a study on the fuzzy based approach for the safety assessment of human body under ELF electric and magnetic(EM) field considering power system states. The analysis of ELF EM field based on quasi-static method is introduced. UP to the present, the analysis of ELF EM field has been conducted with the consideration of one transmission line, or a power line model only In this paper, however, the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes and the states are classified into two types, normal state resulting from normal operation and emergency state from outages. In order to analyze the uncertainty in the normal state, the Monte Carlo Simulation, a statistic approach was introduced and line current and bus voltage distribution are calculated by a contingency analysis method, in the emergency state. To access the safety of human body, the approach based on fuzzy linguistic variable is adopted to overcome the shortcomings of the assessment by a crisp set concept. In order to validate the usefulness of the approach suggested herein, the case study using a sample system with 765(kV) was done. The results are presented and discussed.

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