• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.7
• /
• pp.1141-1149
• /
• 2008

Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. This paper proposed to a FI(Fault Indicator) generation algorithm in ungrounded system. The algorithm just using line-to-line voltage and zero-sequence current detects fault line, fault phase, fault section and FI(Fault Indicator) at terminal device, This paper also proposed to application plan for this algorithm. In the case study, the proposed algorithm has been testified in demo system by Matlab/Simulink simulations.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1297-1302
• /
• 2004

In DC power distribution system for urban rail transits potential relay, 64P, is used to detect the ground faults. The problem with this 64P is that though it detects the ground fault it cannot identify the faulted region. Therefore the faulted region cannot be isolated properly. It could results in power loss of the trains on the healthy regions and the safety of the passengers in the trains could be affected adversely. A new ground fault protective relaying scheme that can identify the faulted region is presented in this paper. The new concept uses the current differential scheme and the permissive scheme to identify the faulted region correctly. A device with similar characteristic to the arrestor is adapted to use the current relay for the ground fault detection. The role of the device is to block the ground leakage current in normal operating condition and enable the ground fault current to flow in ground fault condition. The algorithm of the new relay and the effect of the newly adapted device in the new relaying scheme are discussed.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1440-1443
• /
• 1999

This paper proposes fault detection method using a neural network & fuzzy logic on distribution lines. Fault on distribution lines is simulated using EMTP. The pattern of high impedance fault on pebbles, ground and short-circuit fault were take as the learning model. In this paper proposed fault detection method is evaluated on various conditions. The average values after analyzing fault current by FFT of even odd harmonics and fundamental rms were used for the neural network input. Test results were verified the validity of the proposed method

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.1114-1117
• /
• 1998

Recent applications of neural networks to power system fault diagnosis have provided positive results and have shown advantages in process speed over conventional approaches. This paper describes the application of neural network to fault detection and classification in distribution lines using the fundamental component, 2-5th harmonics index, even and odd harmonics index, and zero phase current. The Electromagnetic Transients Program (EMTP) is used to obtain fault patterns for the training and testing of neural networks. The proposed fault detection and classification method in distribution lines is obtained by analysing the difference among normal, HIF, ground fault, short circuit fault condition.

• Proceedings of the KIEE Conference
• /
• 2008.10c
• /
• pp.215-217
• /
• 2008

DC fraction system can damage human and other facilities due to the rising of rail potential. Therefore the earth fault detection relay protects system using rail potential induced in train operation and ground fault. However the conventional protection system cannot operate due to the fault resistance and might operate unwanted voltage rising due to the other substation ground fault. So this paper models DC traction system using PSCAD/EMTDC and simulates the rail potential rising. We can estimate the rail potential rising in DC traction system through the various simulation.

• Nuclear Engineering and Technology
• /
• v.48 no.1
• /
• pp.211-217
• /
• 2016

Most nuclear power plants now utilize solid grounded low voltage systems. For safety and reliability reasons, the low voltage (LV) high resistance grounding (HRG) system is also increasingly used in the pulp and paper, petroleum and chemical, and semiconductor industries. Fault detection is easiest and fastest with a solidly grounded system. However, a solidly grounded system has many limitations such as severe fault damage, poor reliability on essential circuits, and electrical noise caused by the high magnitude of ground fault currents. This paper will briefly address the strengths and weaknesses of LV grounding systems. An example of a low voltage HRG system in the LV system of a nuclear power plant will be presented. The HRG system is highly recommended for LV systems of nuclear power plants if sufficient considerations are provided to prevent nuisance tripping of ground fault relays and to avoid the deterioration of system reliability.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.53 no.3
• /
• pp.161-165
• /
• 2004

In this paper, we have designed the ground faults detection and interrupting controller at normal condition of AC 120v to 240v rating voltage. Ground faults in electrical network have the characteristics of low current, 60㎐ frequency to 2㎑frequency. The load condition are no load and 20A load. The trip level of the controller is 6㎃ with ground faults. The Controller algorithm is implemented using pic16c71 microprocessor.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.1205-1208
• /
• 2005

By adding user interface to the usual router, an improved functional router is implemented in this paper. Due to the massive amount of spatial data processing, spatial information processing area has been rapidly grown up in recent years based on powerful computer hardware and software development. Spatial index structures are the core engine of geographic information system(GIS). Analyzing and processing of spatial information using GIS has a lot of applications and the number application will be increased in the future. However, study on the under ground is in its infancy due to invisible characteristic of this information. This paper proposes the sub-surface fault detection system using the sub-surface layer information gathered from elastic wave. Detection of sub-surface fault provides very important information to the safety of above and sub-surface man made structures. Development of sub-surface fault detection system will serve as a pre-processing system assisting the interpretation of the geologist.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.463-468
• /
• 1987

In this paper, a high impedance fault detection on 22.9kV multigrounded distribution system that has been very difficult by any existing conventional protective relaying systems is studied. Because the fault current is very low, it cannot be distinguished from neutral current caused by load unvalanced on multigrounded distribution system. We developed the new and best algorithms of high impedance ground fault detection. This algorithms are 'the even order power method, even order ratio method', 'and even order ratio varience method'. Using this algorithms, a detection device for high impedance faults is constructed and tested in the laboratory. And continually, it is installed and has been tested in KEPCO substations.

• Journal of Electrical Engineering and Technology
• /
• v.3 no.4
• /
• pp.484-490
• /
• 2008

In this paper, an integrated fault section detection and isolation strategy is proposed based on the application of the Distribution Automation System(DAS) utilizing advanced IT and communication technologies. The Feeder Remote Terminal Unit(FRTU) has been widely used to collect data in the Korean distribution system. The achieved data is adopted in this method for detecting multiple fault types. Especially in the case of single phase-to-ground fault, the fault section is detected by comparison of the zero-sequence current phase angle. The test results have verified the effectiveness of the proposed method in a radial distribution system through extensive simulations in Matlab/Simulink. Furthermore, a communication-based demo system identical to the simulation model has been developed, and it can be applied as an online monitoring and control program for fault section detection and isolation.