• Title/Summary/Keyword: Distance Relay

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A Probabilistic Approach to the Protection Capability Evaluation of Distance Relay in Transmission Systems

  • Zhang, Wen-Hao;Lee, Seung-Jae;Choi, Myeon-Song
    • Journal of Electrical Engineering and Technology
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    • v.5 no.3
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    • pp.407-414
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    • 2010
  • This paper proposes a probability measure for the evaluation of relay performance from two aspects, namely, correct trip and no-unwanted trip. They are developed based on the relationship between relay settings and relay measurements, which follow a Gaussian probability model. The proposed method based on strict mathematical derivation is applied to protection capability evaluation of distance relays under various settings. Considering the specific attributes of each protection zone, the optimal settings are also determined accordingly. The protection capability could demonstrate clearly the relay performance under various settings and the optimal settings could provide good references for engineering applications.

A Study on Distance Relay Modeling Using EMTP (거리 계전기의 EMTP 모델링에 관한 연구)

  • Shim, Jae-Chul;Ryu, Chang-Won;Kang, Yu-Won;Yim, Wha-Yeong
    • Proceedings of the KIEE Conference
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    • 1997.07c
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    • pp.997-999
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    • 1997
  • This Paper presents a relay modeling technique to deal with the relay transient characteristics. Existing relay models are based on steady-state concepts. The ninth-order state space mathematical model of the Mho distance relay has been constructed. Computer modeling of a typical distance relay is done within the Transient Analysis of Control System(TACS) subsection of the ElectroMagnetic Transient Program(EMTP).

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A Study on the Development of the Digital Distance Relay Simulator for Education using GUI (GUI를 이용한 교육용 디지털 거리계전기 시뮬레이터 개발에 관한 연구)

  • Kim Dong-Su;Kim Chul-Hwan;Lee Ki-Teak;Park Nam-Ok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.8
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    • pp.388-395
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    • 2005
  • It has always been of great importance in the electrical power system to educate an algorithm on the digital relaying, but it is difficult to educate an algorithm of a digital distance relay on power system because of exclusiveness of the relaying algorithm on power system. Therefore, we need a digital distance relay simulator, which can simulate the algorithm of the digital relaying on transmission line. In this Paper, we extract fundamental components using digital signal processing from data which are a variety of the simulated faults by EMTP. Then this simulator represents instantaneous values, ms values and symmetrical components that are calculated by fundamental components of voltages and currents. The Simulator also represents the zones of a digital distance relay and the locus of an impedance using GUI. Consequently, the developed simulator is particularly useful for understanding of the fundamental concepts of a distance relaying algorithm from a power system engineer points of view.

Improved Coordination Method for Back-up Protection Schemes Based on IEC 61850 (IEC 61850 기반 후비보호계전시스템 보호협조 개선방안)

  • Kim, Hyung-Kyu;Kang, Sang-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.1
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    • pp.43-49
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    • 2011
  • A distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, Zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome this problem clearly, this paper describes an improved backup protection coordination scheme using an IEC 61850-based distance relay for transformer backup protection. IEC 61850-based IED(Intelligent Electronic Device) and the network system based on the kernel 2.6 LINUX are realized to verify the proposed method. And laboratory tests to estimate the communication time show that the proposed coordination method is reliable enough for the improved backup protection scheme.

The Real-Time Distance Relay Algorithm Using fault Location Estimation Information for Parallel Transmission Line (병행 2회선 송전선로에서 고장점 위치 추정정보를 이용한 실시간 거리계전 알고리즘)

  • 이재규;유석구
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.3
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    • pp.183-192
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    • 2003
  • This paper presents the real-time implemented distance relay algorithm which the fault distance is estimated with only local terminal information. When a single-phase-to-earth fault on a two-parallel transmission line occurs, the reach accuracy of distance relay is considerably affected by the unknown variables which are fault resistance, fault current at the fault point and zero- sequence current of sound line The zero-sequence current of sound line is estimated by using the zero sequence voltage which is measured by relaying location Also. the fault resistance is removed at the Process of numerical formula expansion. Lastly, the fault current through a fault point is expressed as a function of the zero-sequence current of fault line, zero-sequence current of sound line, and line, and fault distance. Therefore, the fault phase voltage can be expressed as the quadratic equation of the fault distance. The solution of this Quadratic equation is obtained by using a coefficient of the modified quadratic equation instead of using the square root solution method. After tile accurate fault distance is estimated. the mote accurate impedance is measured by using such an information.

Performance Evaluation of D2D Advertisement Dissemination Algorithms with Maximum Distance and Transmission Efficiency Based Relay Selections (D2D 광고 확산을 위한 최대거리 기반 알고리즘과 최대효율 기반 알고리즘의 성능 분석)

  • Kim, Junseon;Lee, Howon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.2
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    • pp.287-292
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    • 2015
  • In this paper, we evaluated the performance of D2D advertisement dissemination algorithms with maximum-distance and transmission-efficiency based relay selections with respect to the total number of successfully received users and transmission efficiency. To assume more practical environment, we took into account pre-defined target-areas based on the information of user density and the limit for the maximum number of relay users. Through the simulations we compared the performance results of both D2D advertisement dissemination algorithms with maximum-distance and transmission-efficiency based relay selections according to increment of the number of sectors. And then, we analysed the superiority of algorithm with transmission-efficiency based relay selections more than maximum-distance based relay selections.

Examination with Transmission Line Distance Relay Setting Rule Considering Error (오차를 고려한 송전선 보호 거리계전 정정룰에 대한 고찰)

  • Cho, Seong-Jin;Choi, Myeong-Song;Hyun, Seung-Ho;Kim, Joung-Wook;Lee, Joo-Wang;Cho, Bum-Sub;Yoo, Young-Sik
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.12-15
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    • 2002
  • Korea Power System Protection Setting Rule was used from the rectify 1990's. Thereafter transmission voltage is raised the voltage into 765kV, and introduction to new technology of Power System, and was many of variation but, it is using. The present is using Digital type distance relay for 765kV transmission line protection. If impedance value of transmission line were to value lower than setting, this would be operating and relay setting rule is for 85% into Zone 1 self section, and Zone 2 is a 125%, Zone 3 is a 225%. Which's $15{\sim}25%$ include current transformer error 5%, potential transformer 5%, relay calculation error 5% and margin factor from the field experience. This paper is discussed transmission protective relay and relay setting rule of high voltage power system and we verify the correctness relay setting rule with distance relay using Matlab simulation.

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An Algorithm of Predicting the Zone 3 Trip Time of Distance Relay by using PMU Data when Power Systems Face Cascaded Event on Transmission System (송전 계통의 광역정전 징후 시 PMU 취득 데이터를 이용한 거리계전기 Zone3 동작시간 예측 알고리증)

  • Kim, Jin-Hwan;Lim, Il-Hyung;Lee, Seung-Jae;Choi, Myeon-Song;Kim, Tae-Wan;Lim, Seong-Il;Kim, Sang-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.12
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    • pp.2303-2310
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    • 2009
  • Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be attributed to improper operations of protective relays. Especially, it is the most dangerous problem that trips of backup relays by overload. In this paper, a new algorithm of predicting Zone 3 acting time of distance relay is proposed using the real time synchronized data from PMUs on the transmission system when the power system is danger. In the proposed, some part of the power system are outage when some unexpected fault in the power system, the algorithm will monitor the impedance locus of distance relay. At this time, if there is a big change of Impedance locus, the algorithm will calculate the Zone 3 acting time of the distance relay by the over load. In the case studies, the estimation and simulation network have been testified and analysed in Matlab Simulink.

RFID Distance Bounding Protocol to Secure Against Relay Attack by Using Full-Response (Full response를 사용하여 중계 공격에 안전한 RFID 거리제한 프로토콜)

  • Kwon, Hye Jin;Kim, Soon Ja
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.3
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    • pp.298-300
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    • 2016
  • We propose a RFID distance bounding protocol that RFID tag still responds when reader sends a void challenge in order to reduce the probability of a relay attack. We analyze the success probability of relay attack depending on the full challenge ratio. Our experimental results show that our protocol is secure to relay attack.

Development of An Expert System to Decide the Resetting Area of Protective Distance Relay in Power Transmission Systems (송전계통 보호 거리계전기 재정정 영역 판정 전문가시스템 개발)

  • 최면송;민병운;김기화;현승호;이승재
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.8
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    • pp.437-443
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    • 2003
  • In this paper an expert system is developed to decide the resetting area of protective devices in power transmission systems. A configuration change in power transmission networks from a substation extension such as new line or bus addition need resetting of protective devices around the point of configuration changes. To find the resetting area in complex power system is very difficult, especially when the distance protective relays are considered to be reset. The proposed expert system, in this paper to find the resetting area has many rules based on the changes of fault currents and apparent factors from the power system alteration. It solves the problem to find relay resetting area using the network information in the database and the rule-base. The case study shows a result of the problem to find relay resetting area in KEPCO system when there is any configuration change.