نتایج جستجو برای: directional protection

تعداد نتایج: 214574  

2016
A. Rahmati

Power transformers are protected by different relays that operate independently. Malfunction of each relay has a major role in reducing the reliability of the protection system. In order to mitigate the main drawbacks of the power transformer relays, an overall protection scheme is presented in this paper. This scheme proposes a novel multi criterion algorithm using decision-making based on fuz...

2015
K. NARENDRA N. PERERA ERLPhase Power

The paper presents the performance of a novel distributed bus differential protection scheme, which utilizes independent multi-principle advanced protection algorithms, including differential percent slope, delta phase directional comparison, rate of change of differential (ROCOD) currents, delta phase directional comparison on neutral current differential, and a check zone to secure the electr...

2010
A. Rathinam D. Sattianadan K. Vijayakumar

The main function of the protective devices in the power system is to detect and remove the selected faulty parts as fast as possible. Directional over current relays are commonly used for the protection of interconnected sub transmission systems, distribution systems, or as a secondary protection of transmission systems. For the systems having more than one source connected, that is meshed or ...

2013
Chengxi Liu Zakir Hussain Zhe Chen Claus Leth Bak

The increasing penetration of dispersed generation (DG) brings challenges to conventional protection approaches of distribution system, mainly due to bi-directional power flow and variable fault current contribution from different generation technology-based DG units. Moreover, the trend of allowing islanded operation of distribution systems necessitates the adoption of adaptive protection meth...

2009
Wen Chen

As the primary transportation tools for modern people, Autos are facing a tremendous transform. With shortcomings which couldn’t be overcome, Ancient animal-drawn vehicle had been replaced by motor vehicles. However, motor vehicles still have inextricable malpractices such as lower security, lower speed, dependent for energy sources, lacking of environmental protection, single purpose, lower ef...

2015
Mohamed Zellagui Almoataz Youssef Abdelaziz

1841 M. Zellagui & A.Y. Abdelaziz, Optimal Coordination of Directional Overcurrent Relays using Hybrid PSO-DE Algorithm  Abstract — This paper presents a new approach for the optimal coordination of IDMT directional overcurrent relays in meshed power systems using a hybrid particle swarm optimization based differential evolution algorithm (PSO-DE). In protection coordination problem the total ...

2016
Elham salahi M.Shahram M. Jayalakshmi S. N. Merchant Uday B. Desai

The authors propose a new hybrid watermarking scheme for copyright protection of color images using contourlet transform and singular value decomposition. The host color image and color watermark images are decomposed into directional sub-bands using contourlet transform and then applied Singular value decomposition to mid frequency sub-band

2004
Lukasz Kawulok Krzysztof Zielinski Michal Jaeschke

This paper presents Group Membership Service for JXTA extended with single or bi-directional authentication. The proposed solution exploits certificates and PKI (Public Key Infrastructure). All information about the system's users is kept in the LDAP. An attention has been also paid to the problem of a private key secure protection.

Journal: :journal of chemical and petroleum engineering 2014
abdolnabi hashemi afshin ghanbarzadeh siamak hosseini

the dogleg severity is one of the most important parameters in directional drilling. improvement of these indicators actually means choosing the best conditions for the directional drilling in order to reach the target point. selection of high levels of the dogleg severity actually means minimizing well trajectory, but on the other hand, increases fatigue in drill string, increases torque and d...

Journal: :transactions on combinatorics 2013
p.siva kota reddy u. k. misra

let $g=(v, e)$ be a graph. by emph{directional labeling (ord-labeling)} of an edge $x=uv$ of $g$ by an ordered $n$-tuple$(a_1,a_2,...,a_n)$, we mean a labeling of the edge $x$ such thatwe consider the label on $uv$ as $(a_1,a_2,...,a_n)$ in thedirection from $u$ to $v$, and the label on $x$ as$(a_{n},a_{n-1},...,a_1)$ in the direction from $v$ to $u$. inthis paper, we study graphs, called emph{...

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