• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.11
• /
• pp.647-654
• /
• 2003

As electrical power system has become complicated and enlarged to cope with the increasing electric demand, it has to be expected that higher speed, higher reliability, higher function and higher arithmetic ability in protective relay should be realized. Therefore, in this papers, by hardware design and implementation used DMA controller that transfer blocks of data to any location in the memory map without interfering with CPU operation, CPU utilization is increased effectively, as a result it made possible to implement multi-function digital protective relay which has high trust and high function of protection as well as control and metering for power transformers using single processor(DSP).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.32 no.4
• /
• pp.313-319
• /
• 2019

Induction motors connected with a three-phase AC system may malfunction due to reverse phase or open phase faults. Conventional overcurrent relays and overheating relays are used to prevent such accidents; however, their drawbacks include a low response speed and false operation. Therefore, in this study, a digital relay for the reverse-open phase was designed and fabricated. This relay can detect the reverse phase and open phase faults and send a trigger signal to the control circuit. The proposed relay was developed based on a microcontroller. The detection times of the reverse phase and open phase were verified as 320ms and 80ms, respectively. Compared with conventional relays that only protect the motor from one type of fault, the proposed relay can detect both, reverse phase and open phase faults. In addition, the fault detection, identification criterion, and trigger signal patterns can be modified by programming according to the requirements of users.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1229-1231
• /
• 2002

This paper presents the design of DC protection system of Light Rail Transit system. Especially, the composition and interface for DC Switchgear. Digital protection unit and sort of protection algorithm are focused. DC Switchgear (DCSWGR) for LRT testline consist of 5 different panels with peculiar characteristics are examined. Also Basic actuation principle for DC fault select relay (50F), Line Test Device (LTD), DC Overcurrent(OCR) relay are introduced.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.423-425
• /
• 2005

Te digital simulation of electric power system is a very important tool that can decide a proper protection systems from the design of the systems. Protection systems base on the wrong simulation results can cause a serious danger in the stability of the power system. So, the power system makes for simulation and the actual power system must be maximumly homologized. In this paper, protection relay models used in actual systems were developed in the PSS/E.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.3
• /
• pp.158-164
• /
• 2003

This paper proposes a percentage current differential relaying algorithm for bus protection using an advanced compensating algorithm of the secondary current of current transformers (CTs). The compensating algorithm estimates the core flux at the start of the first saturation based on the value of the second-difference of the secondary current. Then, it calculates the core flux and compensates distorted currents using the magnetization curve. The algorithm Is unaffected by a remanent flux. The simulation results indicate that the proposed algorithm can discriminate internal faults from external faults when the CT saturates. This paper concludes by implementing the algorithm into a TMS320C6701 digital signal processor. The results of hardware implementation are also satisfactory. The proposed algorithm can improve not only stability of the relay in the case of an external fault but sensitivity of the relay in the case of an internal fault.

• Proceedings of the KIEE Conference
• /
• 1988.11a
• /
• pp.95-97
• /
• 1988

A method of digital transmission line protection using travelling wave is presented. It is shown that the fault current appears as a difference of two quantities associated with the travelling wave at each terminal. The phasor of these quantities are extracted and transmitted to the other end via communication channel to detect the line fault.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.946-958
• /
• 2009

Lately, Seoul metro is changing transformation facilities which have been operated in subway line 1 and 2 for a long duration of time. Although the exiting protection relays in DC feeder system have such several functions as 76I, 50, 85, and 64P, the new protective relay have a great variety of functions such as 76I, 76D, DDL-I, DDL-T(Imin), 85, and 64P, as well as record and save various events and accident wave in order to review and analyze the working causes of the protective system. However, because the new digital relays are not used properly for protective propose, there are the cases that the electric accident is deteriorated more. Therefore, in this paper, we will describe that making the use studying installation intention, direction, and setting up value of the protection relay in DC breaker operation not only prevents from making the electric accident worse but also shows the efficient operation method of direct current protection system.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.625-626
• /
• 2007

This study is on the protection system of Korean power system applying superconducting power devices. We investigates firstly protection systems of Korean power system and then do a basic study on the impact of relay systems in the power system with superconducting devices. For the more reliable result, we will carry out relay operation tests in the power system applying superconducting facilities using RTDS(Real Time Digital Simulator) in the future.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.902-904
• /
• 1998

When the faults occur in power systems, the protective relay plays a roles of protecting power systems. It is important that the protective relay have high selectiveity and sencitivity performance in power system by correct setting the relays. This paper proposed a testing methods if the reliability of digital relay as simulating the response of relay at faults in the real power system operation environment.

• KIEE International Transactions on Power Engineering
• /
• v.2A no.3
• /
• pp.89-94
• /
• 2002

In this paper, a protection system using a Multi-Agent concept for power distribution networks is proposed. Every digital over current relay(OCR) is developed as an agent by adding its own intelligence, self-tuning and communication ability. The main advantage of the Multi-Agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent. In order to cope with frequent changes in the network operation condition and faults, an OCR agent, suggested in this paper, is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents. Through this kind of coordination and information exchanges, not only a local but also a global protective scheme is completed. Simulations in a simple distribution network show the effectiveness of the suggested protection system.