• 전기의세계
• /
• 제23권1호
• /
• pp.61-68
• /
• 1974

This paper attempts to develop the algorithms and computer program for load flow solution and faults analysis of large power system by small digital computer. The Conventional methods for load flow solution and fault analysis of large power system require too much amount of computer memory space and computing time. Therefore, this paper describes the methad for reducing the computer memory space and computing time as follows. (1) Load Flow Solution; This method is to store each primitive impedance of lines along with a list of bus numbers corresponding to the both terminals of lines, and to store only nonzero element of bus admittance matrix. (2) Faults Analysis: This method is to partition a large power system into several groups of subsystems, form individual bus impedance matrix, store them in the storage, and assemble the only required portion of them to original total system by algorithm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
• /
• pp.74-76
• /
• 2001

When a Bus voltage is low, the Load-Flour is generally blown up. If Bus voltage is normalized. the convergence of Load-flow is improved. This paper introduces virtual bus with tap. In that case, the Bus admittance will be considered. And the convergence of Load-Flow in applying virtual bus is debated.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
• /
• pp.251-253
• /
• 2001

This paper presents a fault location algorithm 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 symmetrical components and admittance load model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
• /
• pp.6-8
• /
• 1993

Short Circuit analysis is one of the most fundamental procedures for power system analysis problem. In order 10 solve the problem, In order to solve the problem, it's required to develop an advanced algorithm by which modified bus admittance matrix are easily computed for a large number of alternative network configuration. This paper proposes a new calculation method to efficiently modify the bus impedance matrix elements of large power system by method for removal of link, and presents its Practicality by applying the proposed method in the power system model.

• Journal of electromagnetic engineering and science
• /
• 제9권2호
• /
• pp.105-109
• /
• 2009

The problem of electromagnetic coupling between a slit fed by a flanged parallel-plate waveguide(PPW) and a slit in an infinite nearby conducting screen parallel to the flanged ground conductor is studied as a simplified problem for a near-field scanning microscopy(NSM). The method of moments isused to solve the coupled integral equations for the electric field distributions over the slits. The performance of the proposed apparatus as an NSM is tested by examining the effects of some geometrical parameters on the equivalent slit admittance and coupled powers through the slits.

• Journal of Advanced Marine Engineering and Technology
• /
• 제28권5호
• /
• pp.837-846
• /
• 2004

This paper presents a screening technique for greatly reducing the computation involved in determining the optimal location and types of Flexible AC Transmission System (FACTS) devices in a large power system. The first-order sensitivities of the generation cost for various FACTS devices are derived. This technique requires solving only one optimal power flow (OPF) to obtain sensitivities with respect to FACTS device control variables for every transmission line To implement a sensitivity-based screening technique, we used a new UPFC model, which consists of an ideal transformer with a complex turns ratio and a variable shunt admittance. A S-bus system based on the IEEE 14-bus system was used to illustrate the technique.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
• /
• pp.506-512
• /
• 1997

Ultrasonic knives have been successfully used for the surgery of many medical fields. However, the conventional ultrasonic knives for surgical operation cannot be controlled its resonant frequency. So if the material to cut has different characteristic impedance then different ultrasonic knife will be needed. Because the optimum driving frequency of ultrasonic knife is different by characteristic impedance of material. In this work, using a frequency variable ultrasonic transducer made of multi-layered PZT vibrator, a frequency controllable ultrasonic knife will be suggested. The design and computation principles will be also derived. For this work, firstly, the characteristics of this ultrasonic knife will be analyzed by transmission line model equivalent circuit, and the free admittance characteristics and vibrational velocity distributions will be obtained. Secondly, we will design and make the frequency controllable electrical oscillator for driving this ultrasonic knife.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
• /
• pp.433-434
• /
• 1988

Rectangular microstrip antenna with parasitic element is analyzed. Radiation admittance and equivalent circuit parameters between rectangular microstrip antenna and parasitic element are obtained by using equivalent ${\pi}$-network parameters of the slit in the wall of the parallel plate waveguide filled with homogeneous dielectric. The return loss is calculated and measured as a function of frequency with gap width 0.5mm between the patch and parasitic element. The experimental results are in fairly agreement with calculated values.

• 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.

• 전기의세계
• /
• 제29권10호
• /
• pp.653-659
• /
• 1980

The paper describes a new technique for the shape design of a bell-type porcelain locke insulator in contaminated environment. Early studies on the contamination performance of insulators indicated the need for an improvable shape to provide adequate insulation strength at normal operating voltages. In this paper, under lightly and heavily contaminated site severity, the variation of voltage distribution to leakage path at insulator surfaces analyzed by the complex admittance matrix using finite element method. By this results, the improvement of shape of insulators could be approached to the available condition in contaminated environments. In applicating to compare a standard disc type with a fog disc type insulator, this design technique is valid.