• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
• /
• pp.255-257
• /
• 1999

Fault location algorithms based on the current distribution factors under the one-phase to earth fault condition of a double-circuit line are presented. The derivation method for current distribution factors is showed, to calculate fault current, fault resistance and the zero sequence current of other parallel circuit which are unknown. As the proposed algorithms 1,2,3 embodies an accurate location by the voltage and the current of the relaying point.

• 동의신경정신과학회지
• /
• 제18권2호
• /
• pp.153-162
• /
• 2007

This study is designed to assess the effect of hypnosis on the pain disorder patient. We treated a patient by using hypnosis as well as traditional oriental therapy-acupuncture, herbal medicine, Chu-Na therapy. We divide the pain into four parts and then we checked the intensities of them comparing with those of the first treatment. The pain worsened by psychic factor was decreased after treatment. Especially, after hypnosis, the intensity of the pain is highly changed. Psychotherapy in oriental medicine can be helpful to treat patients who have psychic and physical disorders.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1990년도 하계학술대회 논문집
• /
• pp.162-166
• /
• 1990

This paper proposes a new method of the state reduction in dynamic equations of generators in large electric power system stability analysis. This method assumes study groups whose state trajectories we are interested in, coherency groups whose state trajectories are similar to the other state trajectories of generators in the same coherency group by a certain disturbance. By the weighted sum or the other method, the states of generators in one coherency group can be reduced to the equivalent states of an equivalent generator. This method is shown to be highly efficient in reducing the number of states with small error by the result of case study presented latter part of this paper.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권7호
• /
• pp.815-823
• /
• 1999

This study considers an implementation of artificial neural networks to the receding horizon optimal control and is applications to power systems. The Generalized Backpropagation-Through-Time (GBTT) algorithm is presented to deal with a quadratic cost function defined in a finite-time horizon. A decentralized approach is used to control the complex global system with simpler local controllers that need only local information. A Neural network based Receding horizon Optimal Control (NROC) 1aw is derived for the local nonlinear systems. The proposed NROC scheme is implemented with two artificial neural networks, Identification Neural Network (IDNN) and Optimal Control Neural Network (OCNN). The proposed NROC is applied to a power system to improve the damping of the low-frequency oscillation. The simulation results show that the NROC based power system stabilizer performs well with good damping for different loading conditions and fault types.

• 대한전기학회논문지:전력기술부문A
• /
• 제53권4호
• /
• pp.199-207
• /
• 2004

The 765(㎸) transformer is operated using two parallel tanks because of its high capacity. The protective relay (61) for the current phase balance of a 765(㎸) transformer would misoperate by excessively, circulation current of each tanks caused by a mismatch of ULTC Tap. In this paper, the phenomenon was analyzed, and the setting rules of relay for bank protection are studied. The result of analysis is verified by the simulation of 765(㎸) transformer with the Power Systems Computer Aided Design(PSCAD). Thereby an appropriate setting rule of the current phase balance relay is recommended.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.275-277
• /
• 2001

This paper presents a fault location algorithm using current distribution factors for distribution feeder systems. When a fault occurs in distribution system, an accurate fault distance is important for fast fault restoration. The proposed algorithm achieves a high accuracy using negative sequence circuit with various fault conditions.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.121-123
• /
• 2001

This paper presents a fault location algorithm using iterative method at unbalance condition for distribution feeder systems. Distribution feeders include single phase and three phase laterals. The proposed algorithm achieves a high accuracy by continuously updating voltage and current phasor using the phase components and admittance load model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.249-251
• /
• 2001

The two fuzzy criteria to distinguish the internal fault from the inrush for the power transformer protection have been identified. They are based on the terminal voltage, fundamental and second harmonic component of differential current. A systemetic way to determine the associated fuzzy membership function is also proposed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.278-281
• /
• 2001

Identifying the fault location has to deal with multiple possible candidates. It presents a new technique to diagnosis a fault region. The proposed diagnosis scheme identifies accurately the location based on the protective device operations and load current change at the substation. An Expert system is presented using these facts.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.25-27
• /
• 2001

To verify operation of relay is a difficult job for relay engineers. This paper reports the development of logic simulator. Fault data is generated from EMTP and system information generator. The developed system has a universal characteristics that can deal with any relay logic.