• KIEE International Transactions on Power Engineering
• /
• 제4A권3호
• /
• pp.129-133
• /
• 2004

This paper deals with the design and implementation of a TCSC (Thyristor Controlled Series Capacitor) simulator, which is a module for an analog type power system simulator. Principally, it presents configuration of controller hardware/software and its experimental results. An analog type power system simulator consists of numerous power system components, such as various types of generator models, scale-downed transmission line modules, transformer models, switches and FACTS (Flexible AC Transmission System) devices. It has been utilized for the verification of the control algorithm and the study of system characteristics analysis. This TCSC simulator is designed for 50% line compensation rate and considered for damping resister characteristic analysis. Its power rate is three phase 380V 20kVA. For hardware extendibility, its controller is designed with VMEBUS and its main CPU is TMS320C32 DSP (Digital Signal Processor). For real time control and communications, its controller is applied to the RTOS (Real Time Operation System) for multi-tasking. This RTOS is uC/OS-II. The experimental results of capacitive mode and inductive mode operations verify the fundamental operations of the TCSC.

• Journal of Electrical Engineering and Technology
• /
• 제7권3호
• /
• pp.304-311
• /
• 2012

So far, the importance for an accurate load model has been constantly raised and its necessity would be further more emphasized. Currently used load model for analysis of power system in Korea was developed 10 years ago, which is aggregated by applying the statistically estimated load compositions to load models based on individual appliances. As modern appliances have diversified and rapidly changed, the existing load model is no longer compatible with current loads in the Korean power system. Therefore, a measurement based load model is more suitable for modern power system analysis because it can accurately include the load characteristics by directly measuring target load. This paper proposes a ZIP model employing a Kalman-filter as the estimation algorithm for the model parameters. The Kamlan-filter based parameter identification offers an advantage of fast parameter determination by removing iterative calculation. To verify the proposed load model, the four-second-interval real data from the Korea Energy Management System (K-EMS) is used.

• KEPCO Journal on Electric Power and Energy
• /
• 제5권4호
• /
• pp.343-347
• /
• 2019

When referring to weight, volume, and efficiency, a SuperConducting Synchronous Generator (SCSG) is definitely superior to conventional generators as a large-scale wind power generation system. The SCSG is connected to a full power converter that transmits the energy from the SCSG to the power grid. To reduce the current stress and system cost, the SCSG which has nine-phase armature windings with three converters is used. This paper deals with a comparative analysis of 10 MW superconducting wind power generators with three-phase and nine-phase armature windings. The stator windings of SCSGs are of various types. Using the finite element method, SCSGs are analyzed and compared in terms of the weight and volume of SCSGs, the total length of the superconducting wire, harmonics, torque performance, and efficiency. The analyzed results will be effectively utilized to design large-scale superconducting generators for wind power generation systems.

• 디지털융복합연구
• /
• 제14권6호
• /
• pp.143-150
• /
• 2016

본 논문의 목적은 지상작전 시 피아간 상대적 전투력을 분석하는데 전문가 시스템을 이용하는 방안을 제시하는 것이다. 상대적 전투력 분석은 지휘관 및 참모들이 부대를 어떻게 운용할 것인가에 대한 방향을 설정할 수 있기 때문에, 그 절차는 신속하고 이성적인 의사결정의 과정을 필요로 한다. 여러 애플리케이션들이 탑재될 수 있는 전술정보통신체계가 10년 동안 개발되고 있지만, 상대적 전투력 분석의 절차는 의사결정에 관여한 일부인원들에 의해 수작업으로 진행되어왔다. 본 연구에서는 이론적으로 3가지 상대적 전투력 분석방법을 고찰하고 이를 시스템에 지식(Knowledge)롤 사용될 수 있도록 수치적으로 표현하고, 유형뿐만 아니라 무형의 전투력도 지식에 포함될 수 있는 방안이 연구되었다. 기존의 대대급 전투력 지수와 수치적으로 표현된 지식을 이용하여 상대적 전투력 분석을 위한 전문가 시스템은 EXSYS Corvid로 구현되었다. 의사결정의 오류를 줄이고 빠른 의사결정을 가능하게 하며 유형뿐만 아니라 무형의 전투력까지 의사결정에 반영할 수 있을 것으로 기대된다. 향후에는 전투력 분석뿐만 아니라 인사분야나 정보 분석 분야에도 전문가 시스템을 도입하는 방안이 연구되어 객관적이고 합리적인 군 의사결정체계에 기여해야 한다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제36권7호
• /
• pp.942-947
• /
• 2012

As electricity has been used in ship's propulsion, it is necessary to increase the system voltage and current for the electrical distribution system. So it is required to improve the system safety and efficiency, the power stability, the efficiency of the generation through various analysis of ship's electric power system. In this paper, the electrical service reliability of the power distribution system of semi submersible drilling rigs has been analysed and discussed using ETAP.

• 전기학회논문지P
• /
• 제53권3호
• /
• pp.103-109
• /
• 2004

This paper has presented, taking an example of a gas separation plant, dynamic analysis on frequency decline caused by the over-loading at the generator and the knee point causing voltage instability due to reactive power required by re-acceleration of large induction motors, resulting in phenomena of failure in the conventional frequency load shedding. In order to resolve the voltage instability problem, a design of load shedding system employing under-voltage relays has been proposed to the industrial power system containing large induction motors in addition to the conventional load shedding employing frequency relays. For the purpose of dynamic analysis, models of gas turbine and governor, synchronous generator, brushless exciter, and induction motor are introduced.

• 한국산업융합학회 논문집
• /
• 제23권1호
• /
• pp.65-71
• /
• 2020

Recently, interest in the DC transmission is rapidly increasing worldwide. In many countries and leading companies are prior to the aggressive development of HVDC technology and application. Especially, VSC-HVDC system has been widely applied to transfer power at long distance between power plant and power consumption area. Therefore in this paper, we analyzed the benefit-cost of VSC-HVDC system which has more advantages than existing transmission system. The proposed system is MMC(Modular Multilevel Converter) VSC-HVDC system that have stability of Power Grid, interconnect Large-scale New Power Generation Plants by prevents Blackout. And MMC VSC-HVDC system Reduced the loss importing foreign systems. And the benefits were calculated in four stages, and the costs were applied to the actual project. By evaluating the various avoidance costs compared to the benefit-cost, it was confirmed that MMC VSC-HVDC system was advantageous in system stability and economic and social benefits.

• 전기학회논문지
• /
• 제61권8호
• /
• pp.1210-1215
• /
• 2012

Traction motors for driving and power conversion devices using semiconductor switch are equipped with a transportation systems such as an electrical railway system. Power conversion devices have the possibility of malfunction by external electromagnetic waves. As a result, these could affect the safe operation of the railway. Moreover, the electromagnetic waves above safe limits will be harmful to the passengers inside the railway vehicles or anyone working around the rail-track. For this reason, the importance and need about the reliability check and complement of electromagnetic waves generated from the IPT(Inductive Power Transfer) system have been suggested for the safe application of the IPT system to the railway system. In this study, prediction for the electromagnetic wave properties was conducted through FEM(Finite Element Method) analysis of 5kW-class IPT system design model. Next, the 5kW IPT system prototype was made and then the small-scaled railway vehicle was made to mount the IPT system and the energy management system. Finally, the electromagnetic waves generated from the real small-scaled IPT system were measured and analyzed, and then the reliability check of predictions by FEM analysis were carried out.

• Journal of Power Electronics
• /
• 제15권1호
• /
• pp.86-95
• /
• 2015

An active clamp high step-up boost converter with a coupled inductor is proposed in this paper. In the proposed strategy, a coupled inductor is adopted to achieve a high voltage gain. The clamp circuit is included to achieve the zero-voltage-switching (ZVS) condition for both the main and clamp switches. A rectifier composed of a capacitor and a diode is added to reduce the voltage stress of the output rectifier diode. As a result, diodes with a low reverse-recovery time and forward voltage-drop can be utilized. Since the voltage stresses of the main and clamp switches are far below the output voltage, low-voltage-rated MOSFETs can be adopted to reduce conduction losses. Moreover, the reverse-recovery losses of the diodes are reduced due to the inherent leakage inductance of the coupled inductor. Therefore, high efficiency can be expected. Firstly, the derivation of the proposed converter is given and the operation analysis is described. Then, a steady-state performance analysis of the proposed converter is analyzed in detail. Finally, a 250 W prototype is built to verify the analysis. The measured maximum efficiency of the prototype is 95%.

• 신재생에너지
• /
• 제19권4호
• /
• pp.61-71
• /
• 2023

The necessity of energy utilization using livestock manure has been proposed with the decrease in domestic agricultural land. Livestock manure solid fuel has been investigated as a promising energy resource owing to its convenient storage and use in agricultural and livestock fields. Additional electricity production is possible through the integration of a biomass combustion boiler with the organic Rankine cycle (ORC). In this study, a mathematical system model of the cattle manure solid fuel boiler integrated with the ORC was developed to analyze the components' performance under variable operating conditions. A sensitivity analysis was conducted to confirm the electrical efficiency of the ORC turbine and the applicability of this system. The minimum required waste heat recovery rate was derived considering the system marginal price and levelized cost of electricity of the ORC. The simulation results showed that, in Korea, more than 77.98% of waste heat recovery and utilization in ORC turbines is required to achieve economic feasibility through ORC application.