• 전기학회논문지
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• 제67권9호
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• pp.1141-1145
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• 2018

Generally, in nuclear plants, distance relay (21R) has adapting to protect and to operate main protective of transmission lines and backup protective of main generator. Operation of 21R was required and based on exactly accurate calculation and criteria. But presently method of 21R setting has applied according to protection devices operation guide of KPX, excepting IEEE and ISA standards, which have a difference review directions, consider parameters and devices, also consideration factors were affected to relay operations by uncertain guides. therefore this paper proposed new protection relay setting method and unvague criteria from IEEE 741 and ANSI/ISA 67.04.01, and reviewed a different results through numerical calculation results for methods and criteria including previous and established 21r setting by IEEE, ANSI/ISA Technical standards.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.31-33
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• 2000

This paper discusses the operational characteristic analysis of distance relay depending on the power system parameters in transmission line including FACTS devices. Distance relay requires protective coordination because the FACTS devices change power system parameters to increase power transmission capacity. In this paper, the dynamic operational characteristics of distance relay are analyed for the effect of fault resistance and operation mode of FACTS devices according to the installed points of these devices.

• 대한전기학회논문지:전력기술부문A
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• 제53권3호
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• pp.161-167
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• 2004

Zone 3 of the distance relay is used to provide the remote back-up protection in case of the failure of the primary protection. However, the risk lot mal-operations under stressed conditions such as heavy loading, voltage and transient instability is usually high. Zone 3 is used in combination with the derivatives of the voltage, and current, etc to prevent mal-operations. Sometimes, the impedance characteristics that restrict the tripping area of relay are used to avoid the mal-operations due to load encroachment. This paper presents a novel Zone 3 scheme based on combining the steady-state components (i.e. 60Hz) and the transient components (TCs) using a state diagram that visualizes the sequence of studies that emanate from the sequence of events. The simulation results show that the novel zone 3 distance relay elements using the proposed method operates correctly for the various events.

• Journal of Power Electronics
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• 제11권6호
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• pp.890-896
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• 2011

In this paper the impact of a SSSC and a STATCOM on the impedance calculated by a distance relay is investigated. Both analytical analysis and simulations are provided. The STATCOM/SSSC control systems are modeled in detail. It is demonstrated that a SSSC has a greater impact on the calculated impedance by an A-G distance relay element. Several scenarios are considered in the simulations like the impact of the fault conditions, the compensator settings, the power system conditions and so on. All the simulations are carried out in MATLAB/Simulink with detailed models of the SSSC and the STATCOM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.334-336
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• 2003

This paper describes the influences of the large scaled wind farm interconnected with 154 kV power networks on the operational characteristics of distance relay applied in the transmission line. The wind farm composed of wind turbine generators are one of the great energy sources: they can supply the power into an interconnected network not only the normal conditions, but also the fault conditions of power network. Therefore, the distance relay applied in the transmission tine may mal-operate due to the contribution of wind farm. This paper presents the operational characteristics of distance relay for the fault occurred in the transmission line interconnected with wind farm. Simulation results show that it is difficult to recognize the fault location due to the power output of wind farm.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.40-46
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• 2014

The development of the superconducting fault current limiter (SFCL) to apply into a power transmission system where makes larger fault current compared to the power distribution system has been performed. Among various SFCLs, the trigger-type SFCL is suitable for application into the power transmission system due to the effective reduction on power burden of the high temperature superconducting element (HTSC) for the larger fault current. To protect the power transmission line in the power grid, the distance relay, which decides to interrupt fault section where can be calculated by the measured voltage and current from sound grid, is one of important protective devices in the power transmission system. However, the operation of the distance relay from the impedance of the fault point on the transmission line is affected by the impedance of the trigger-type SFCL. Therefore, the analysis on the operational characteristics of distance relay considering the application of the SFCL is required. In this paper, the effect on the operation zones of the distance relay by the impedance of the SFCL in a power transmission system was analyzed through the PSCAD/EMTDC simulation.

• 한국산업정보학회논문지
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• 제17권3호
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• pp.19-26
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• 2012

RFID 시스템에서 중계 공격에 저항하기 위해 리더와 태그 간의 시도와 응답에 소요된 1비트의 왕복 여행시간 측정을 이용한 거리 한정 프로토콜이 주로 사용된다. 이러한 프로토콜에서 1비트 시도와 응답에 대한 중계 공격의 성공확률을 줄일 수 있으면 효율적인 거리 한정 프로토콜을 만들 수 있다. 본 논문에서는 Hancke와 Khun이 제안한 1비트 시도와 응답 기반의 RFID 거리 한정 프로토콜을 2비트 시도와 응답 기반으로 수정한 효율적인 RFID 거리 한정 프로토콜을 제안한다. n번의 시도와 응답에 대한 중계 공격의 성공확률이 제안된 프로토콜에서는 (7/16)n으로 (3/4)n인 Hancke와 Khun의 프로토콜보다 훨씬 낮다.

• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.236-242
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• 2004

Previous research results indicated that the designed current reduction device could effectively reduce the sheath circulating current and that its RDP protection device could shield it against both fault and lightning strokes. In this paper, cable impedance is analyzed using wavelet analysis and distance relay algorithm following the installation of these devices so that the operation of distance relay can be estimated. The test results confirm that in these devices, the fault inception angle and SVL bonding types have no impact on the change of cable impedance. In other words, the conventional distance relay can be used without a new relay setting. Thus we can finally assert that the designed current reduction device and its protection device are effective and can be safely installed on the cable transmission system without disturbance.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.533-540
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• 2017

Distance relay identifies the type and location of fault by measuring the transmission line impedance. However any other factors that cause miss calculating the measured impedance, makes the relay detect the fault in incorrect location or do not detect the fault at all. One of the important factors which directly changes the measured impedance by the relay is series capacitive compensation (SCC). Another factor that changes the calculated impedance by distance relay is fault resistance. This paper provides a method based on the combination of distance and differential protection. At first, faulty transmission line is detected according to the current data of buses. After that the fault location is calculated using the proposed algorithm on the transmission line. This algorithm is based on active power calculation of the buses. Fault resistance is calculated from the active powers and its effect will be deducted from calculated impedance by the algorithm. This method measures the voltage across SCC by phasor measurement units (PMUs) and transmits them to the relay location via communication channels. The transmitted signals are utilized to modify the voltage signal which is measured by the relay. Different operating modes of SCC and as well as different faults such as phase-to-phase and phase-to-ground faults are examined by simulations.

• 대한전기학회논문지:전력기술부문A
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• 제52권10호
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• pp.593-601
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• 2003

Distance realy is tripped by the line impedance calculated at the relay point. Accordingly the accurate operation depends on the precise calculation of line impedance. Impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding resistance, and sheath voltage limiters(SVLs). There are also several grounding systems in cable systems. Therefore, if there is a fault in cable systems, these terms will severely be caused much error to calculation of impedance. Accordingly the proper compensation should be developed for the correct operation of the distance relay. This paper presents the distance calculating algorithm in combined transmission line with power cable using wavelet transform. In order to achieve such purpose, judgement method to discriminate the fault section in both sections was proposed using D1 coefficient summation in db4. And also, error compensation value was proposed for correct calculation of impedance in power cables section.