Sae-Hyuk Kwon

The Study of FACTS Impacts for Probabilistic Transient Stability

This paper proposes a probabilistic evaluation for the transient stability of electrical power systems incorporating FACTS devices. The uncertainties of the fault location and relay operation time play important keys in power system instability evaluation. The TCSC and SVC are employed for the reduction of system instability probability. This method is demonstrated by the WSCC test system and the results are compared with and without FACTS by means of Monte Carlo simulation.

A Study of Improving Regenerative Energy Utilization in Urban DC Railway Systems Through Sharing Substations

This paper deals with the power integration of large urban railway systems to improve regenerative energy utilization. Current regenerative energy utilization is low because there is no special plan for using this energy. If the railway system is integrated with other railway systems, the efficiency is expected to be improved. Through the case studies, to find the realistic effect of integrated operation, real system for the Seoul Metro lines, especially line 5 and 7, had been applied.

Development of Matlab/Simulink Module for Voltage Flicker Simulation in Distribution Power Systems

Power quality simulation plays an important role in many practical cases, for example, when deciding the capacity of the related mitigation devices, assessing the influence of installing a nonlinear load in the distribution part, dissolving the quality issues between utilities and customers, and so on. For these purposes, many dedicated tools have been used in order to assess the level of quality distortions by various kinds of PQ indices. However, there are few modules that can accurately simulate the flicker phenomenon, that is, P st and the nonlinear and chaotic behavior of the electrical arc furnace, which is one of the representative nonlinear loads. This paper deals with the useful and simple modules for the voltage flicker simulation in the distribution and transmission level under the environment of Matlab/Simulink. With these modules, the various conditions of distribution systems and the capacities of arc furnaces with the chaotic characteristic can be easily taken into account.

Enhancement of Interface Flow Limit using Static Synchronous Series Compensators

This paper addresses improving the voltage stability limit of interface flow between two different regions in an electric power system using the Static Synchronous Series Compensator (SSSC). The paper presents a power flow analysis model of a SSSC, which is obtained from the injection model of a series voltage source inverter by adding the condition that the SSSC injection voltage is in quadrature with the current of the SSSC-installed transmission line. This model is implemented into the modified continuation power flow (MCPF) to investigate the effect of SSSCs on the interface flow. A methodology for determining the interface flow margin is simply briefed. As a case study, a 771-bus actual system is used to verify that SSSCs enhance the voltage stability limit of interface flow.

Development of KEPCO equivalent systems for the KEPCO enhanced power system simulator

For real-time power system analysis, there exists a limitation of the scale of the system to be simulated; hence, it is necessary for real-time simulation to develop reduced equivalent systems that preserve the desired properties of the original system. In this paper, a procedure for developing equivalent systems whose scale is within the hardware capacity of the Korea Electric Power Corporation (KEPCO) real-time simulator is proposed. In addition, the KEPCO equivalent systems are developed by applying the proposed procedure. The comparison between the original system and equivalent systems illustrates the capabilities of the proposed procedure.

Experimental verification of 220V incandescent lamp characteristics for the IEC flickermeter

In IEC(International Electrotechnical Commission) flicker standards, only two representative cases for 120 V and 230 V are considered. To expend its applicability to other practical cases, it is necessary to manipulate the measuring algorithm, especially a weighting filter, which can be mathematically derived by changing the frequency characteristics of lamp. This paper presents the experimental procedure to obtain the lamp characteristics of 220 V incandescent bulbs, also known as lamp gain factor, which has never been dealt in the international standards. And the determined parameters of 220 V lamps are compared with those of other types of lamps.

Fiatmome analysis model based on PSCAD/EMTDC for Koman high-speed railway

This paper deals with the AC electric railway system modeling using EMTDC program. This system model is composed of Scott-transformers, auto-transformers, running rails, protection wires, feeders, catenary and contact wires, and so on. After obtaining the fundamental frequency model of the AC electric railway system and analyzing its behavior, we have analyzed and tested Korean high-speed railway system focused on the amplification o f harmonic current to verify the proposed model. The simulation results from the proposed approach and the measurement data from the test are described in the paper.

Power System Stability Prediction Using Line Power Flow

Abstract Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison among the contingencies. Also, this paper discusses a methodology to identify crucial transmission lines of which flows are related with small-signal stability by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict transient stability in real-time. Also, a procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system, and it shows capabilities of the proposed method.