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Wang K.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Liu Y.,Shanghai JiaoTong University | Cui R.,Shandong Heze Power Supply Company | Jiang X.,Shanghai JiaoTong University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011

As an important part of the smart transmission line, dynamic line rating can improve the utilization of transmission equipment and help the operator to know about the current operation status of transmission line. In order to ensure the reliability and safety of the transmission line, a method based on Markov chain Monte Carlo (MCMC) is proposed to assess the operation risk of transmission line using dynamic line rating technology. The main principle of this method can be stated as follows. First, the random sequence of micro-climate monitoring parameters posterior distribution is used to create the wind direction, wind speed and ambient temperature probability distribution model. Secondly, Monte Carlo (MC) simulation is used to predict the distribution of conductor temperature with climate models and the line load current model. Finally, the operation risk indices of transmission line are calculated using the conductor temperature distribution. Typical summer and winter monitoring data are used to analyze the reliability of dynamic rating, the result showing that the operation risk is within the security range and meets the requirements of grid operation and dispatching engineering. © 2011 State Grid Electric Power Research Institute Press. Source

Hou H.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Sun Y.,Shandong Liaocheng Power Supply Company | Sun X.,Shandong Liaocheng Power Supply Company | And 2 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2014

This paper has analyzed the attenuation characteristics of the electromagnetic fields that the partial discharge radiated, and antenna sensitivity coefficient of the receiving antenna. And as these theoretical bases, this paper proposes a new localization algorithm based on the attenuation model of the electromagnetic fields radiated by partial discharge, which realizes the partial discharge positioning in the substation. This method constructs a 3-D space coordinate system in substation, deduces the relationship between the electromagnetic signal peak the antennas receives and the position of the partial discharge source and the antennas, and lists the equations of the partial discharge position. This algorithm only needs the peak of the signal, and does not need the time-delay of the signals, so the data acquisition system and the processing systems are greatly simplified. Finally, we analyze the electromagnetic wave signals that are obtained from electromagnetic wave simulation software, and tested from simulation of partial discharge signal in laboratory. Using the algorithm to calculate the position of partial discharge electrical source, veracity and feasibility of the algorithm is validated. Source

Haifeng Y.,Shanghai JiaoTong University | Yong Q.,Shanghai JiaoTong University | Gehao S.,Shanghai JiaoTong University | Jing C.,Shandong Heze Power Supply Company | And 2 more authors.
International Review of Electrical Engineering | Year: 2013

The basic principle of printed ellipse monopole antenna is discussed. A UHF sensor used for the spatial location of the partial discharge(PD) in substation is designed. With an elliptic microstrip patch structure, the sensor can effectively meet the PD detection requirements because of its advantages of omni-direction, broadband, high sensitivity, low standing wave ratio and good consistency in group delay. The UHF sensors array consisting of multiple sensors is able to undertake spatial location of PD. The spatial detection and location performance of the sensor are verified at the PDexperimental platform in a lab, and the sensors array consisting of such sensor is used for continuous monitoring of PD in the substation field. Laboratory experiment and field application results show that the sensor is able to satisfy requirements in spatial location of PD in substation effective. © 2013 Praise Worthy Prize S.r.l. - All rights reserved. Source

Liu Y.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Wang Y.,Shanghai JiaoTong University | Chen J.,Shandong Heze Power Supply Company | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

The load model for draw-out power winding is established according to operation principle of current transformer, the relationships among power output, second turns, load current and magnetization current is theoretically analyzed when current transformer core is not saturated. Furthermore, its correctness is verified by experiments. Then a novel design method for current transformer draw-out power supply based on power control is proposed. The power output of current transformer draw-out power supply is limited in a narrow range by controlling charge current of farad capacitor, so that current transformer draw-out power supply can adapt for larger range of wire current. Finally, the test result demonstrates that power output of current transformer draw-out power supply is near 1 W for wire current from 30 A~1000 A. © 2010 State Grid Electric Power Research Institute Press. Source

Long P.,Shanghai JiaoTong University | Sheng G.,Shanghai JiaoTong University | Liu Y.,Shanghai JiaoTong University | Lv M.,Shanghai JiaoTong University | And 3 more authors.
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2012

The effective assessment on the operation condition of power transformer is an important means to conduct the condition maintenance for transformer and to improve the reliability of power system. Based on the amount of information of all kinds of online monitoring conditions obtained from the transformer intelligent components, the assessment model for comprehensive condition of transformer is established in this study through the introduction of extension theory. First, with respect to the disadvantage that there is considerable subjectivity in constructing judgment matrix by the traditional analytic hierarchy process (AHP), a new method is adopted to construct the judgment matrix. The orthogonal experimental design method, finite element simulation as well as AHP are adopted to determine the weighting of condition information index with scientific and objective attitude; next, the framework for comprehensive assessment of transformer condition is established with the extension-based comprehensive assessment method to achieve the qualitative and quantitative assessment on the transformer condition. The method is proved to be correct and valid through analysis of examples. © 2012 IEEE. Source

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