• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.190-193
• /
• 2001

In order to verify the efficiency or availability and stability of photovoltaic(PV) generation systems, huge system apparatuses are needed, in general, in which an actual size of solar panel, a type of converter system and some amount of load facilities should be installed in a particular location. It is also hardly possible to compare a Maximum Power Point Tracking (MPPT) control scheme with others under the same weather and load conditions in an actual PV generation system. The only and a possible way to bring above-mentioned problem to be solved is to realize a transient simulation scheme for PV generation systems using real weather conditions such as insolation and surface temperature of solar cell. The authors, in this paper, introduces a novel simulation method, which is based on a real-time digital simulator (RTDS), for PV generation systems under the real weather conditions. Firstly, VI characteristic equation of a solar cell is developed as an empirical formula and reconstructed in the RTDS system, then the real data of weather conditions are interfaced to the analogue inputs of the RTDS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme in this paper. The results shows that the cost effective verifying for the efficiency or availability and stability of PV generation systems and the comparison research of various control schemes like MPPT under the same real weather conditions are possible.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.1104-1111
• /
• 2014

The digital substations are being built based on the IEC 61850 network. The cooperation and protection of power system are becoming more intelligent and reliable in the environment of digital substation. This paper proposes a novel method to prevent the malfunction caused by the Transformer Magnetizing Inrush Current(TMIC) using the IEC 61850 based data sharing between the IEDs. To protect a main transformer, the current differential protection(87T) and over-current protection(50/51) are used generally. The 87T IED applies to the second harmonic blocking method to prevent the malfunction caused by the TMIC. However, the 50/51 IED may malfunction caused by the TMIC. To solve that problem, the proposed method uses a GOOSE inter-lock signal between two IEDs. The 87T IED transmits a blocking GOOSE signal to the 50/51 IED, when the TMIC is detected. The proposed method can make a cooperation of digital substation protection system more intelligent. To verify the performance of proposed method, this paper performs the real time test using the RTDS (Real Time Digital Simulator) test-bed. Using the RTDS, the power system transients are simulated, and the TMIC is generated. The performance of proposed method is verified in real-time using that actual current signals. The reaction of simulated power system responding to the operation of IEDs can be also confirmed.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.8
• /
• pp.665-670
• /
• 2014

In this paper, characteristics of a tidal current power generation system are analysis using power hardware-in-the-loop simulation (PHILS). A 10 kW motor generator set is connected to the real grid through a fabricated 10 kW back to back converter. A power control scheme is applied to the back to back converter. A 2 MW class tidal current turbine is modeled in real time digital simulator (RTDS). Generating voltage and current from the 10 kW PMSG is applied to a 2 MW class tidal current turbine in the RTDS using PHILS. The PHILS results depict the rotation speed, power coefficient, pitch angle, tip-speed ratio, and output power of tidal current turbine. The PHILS results in this paper can contribute to the increasing reliability and stability of the tidal current turbines connected to the grid using PHILS.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1094_1095
• /
• 2009

최근 분산전원 시스템들이 가정이나 공공기관 등에 많이 설치되면서 계통에 많은 문제점을 일으키고 있다. 이러한 문제점을 연구하기 위해서는 계통 등의 실제 시스템을 설치하여 실험을 하여야 하는데 학교 연구실 입장에서는 실제 시스템을 설치하여 실험하는데 한계가 있다. 그러나 실시간 전력 계통 모의장치 (Real Time Digital Simulator)를 이용하여 실시간으로 시스템을 시뮬레이션 할 경우 다양한 알고리즘의 적용이 가능하고, 고장, 전력계통 과도현상 등 계통에 일어날 수 있는 여러 가지 상황을 손쉽게 고려해 보는 것이 가능하다. 본 논문에서는 RTDS 내 계통 연계형 태양광 발전시스템을 실제 시스템과 유사하게 모델링하고, 실제 DSP (Digital Signal Processor) 를 이용하여 시스템을 실시간으로 운전하는 HILS (Hardware In the Loop System) 시스템을 구성하였다.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.1163-1165
• /
• 1987

A novel temperature difference-to-frequency converter using two resistance temperature detectors (RTDs) has been developed. The resistance difference of two RTDs is converted into its equivalent inductance to form the resonant circuit of the Colpitts oscillator. The conversion sensitivity of $16\;Hz/^{\circ}C$ and the residual nonlinearity less than 2.15% over the temperature difference range from $35^{\circ}C$ to $155^{\circ}C$ are obtained by the prototype converter. The frequency drift of oscillator itself is ${\pm}0.5\;Hz$. Thus, the minimum detectable temperature difference is estimated to be ${\pm}0.013^{\circ}C$. The proposed converter, except for two RTDs, can be fabricated in monolithic IC form.

• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.302-304
• /
• 2006

본 연구에서 개발한 실시간 시뮬레이터에 적용 가능한 발전단 사고 모의를 위한 정밀 모델 개발 목적은 발전단에서 발생되는 다양한 사고 중 전기적 형태로 모의 가능한 사고를 분류하고 실시간 시뮬레이터로 모의하도록 발전기 모델 및 보호계전요소 모델을 개발하여 이를 현장 실무 교육 및 훈련에 활용하기 위한 것이다. 본 연구에서는 RTDS/RSCAD로 구현 가능한 6가지 계전 요소(거리계전, 주파수, 역전력, 과여자, 과전압, 동기탈조)에 대해 모델링하였다. 그리고 보호계전기가 효과적인 보호계전을 수행할 수 있도록 계전기 신호 처리 모듈, 거리계전기 모듈, 역전력 모듈, 과여자 모듈, 주파수 모듈, 과전압 모듈, 동기탈조 모듈을 UDC를 이용하여 개발하였다. 그리고, 각 요소의 출력에 대해서 Flex Logic을 이용하여 최종적으로 계전기의 트립을 결정하는 모듈을 개발하였다. 또한 발전단 사고에 따른 발전기 보호 과정을 모의함으로써 발전회사 발전기 운전원들이 실제적인 발전기 동특성 및 발전기 보호계전기의 동작을 이해할 수 있도록 하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.6
• /
• pp.303-308
• /
• 2005

As the cost of photovoltaic(PV) generation systems continues to decrease, utility interactive systems are becoming more economically viable. Furthermore, increases in consumer awareness correspond to a willingness to pay a premium price for clean electrical energy generated using renewable energy resources. Especially, PV generation systems, in particular, is undergoing a rapid expansion-showing an industrial growth of approximately 40$\%$ per year in the worldwide, as PV cell and systems technology improve new markets become increasingly accessible. This has resulted in an increased demand for the simulation scheme and operational technologies of utility interactive PV devices and systems. The simulation schemes that can be applied to the utility interactive PV generation systems readily and cheaply under various conditions considering the sort of solar cell, the capacity of systems and the converter system as well are strongly expected and emphasized among researchers. So far, authors have been introducing the simulation method of PV generation systems with several papers. In this paper, authors introduce the simulation way of PV generation systems using EMTP type simulators; EMTP/ATP, EMTDC/PSCAD, RTDS, with each examples. And, by connecting the voltage amplifier to the RTDS a novel simulation method which is extremely close to the real condition of PV generation system is also introduced.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.7
• /
• pp.51-57
• /
• 1995

The theoretical analysis for AlInAs/GaInAs resonant tunneling diodes (RTDs), which have shown the improved negative differential resistance (NDR) characteristics, has scarcely been made in comparison with AlGaAS/GaAs RTDs. In this paper, the static current-voltage relation of Al$_{0.48}In_{0.52}As/Ga_{0.47}In_{0.53}$As RTDs were numerically estimated by using a self-consistent method. Assuming a simplified RTD with single quantum well structure and spacer layers, the peak current density (J$_{P}$) and the peak-to-valley current ratio (PVCR) were analysed as the function of the thickness of the well, the barrier and the spacer layer, and temperature. As the results, the peak current density and the peak-to-valley current ratio indicated a reciprocal relation roughly in respect to the thicknesses of the well and the barrier, and it was theoretically predicted that it be not attainable to provide a high peak current desity (J$_{P}$) over 1${\times}10^{5}A/cm^{2}$ as well as the large peak-to-valley current ratio (PVCR) over 10 that were the the critical conditions for the practical use.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.572-576
• /
• 2011

The operation of permanent magnet synchronous generator (PMSG) type wind power generation system (WPGS) can be affected by the utility condition. Consequently, transient condition of utility should be analyzed for the safe and reliable operation of WPGS. This paper presents transient analysis results of a PMSG type WPGS using real time digital simulator (RTDS). A fault condition was applied to the transient analysis of PMSG type WPGS as the transient grid condition. The simulation results were analyzed to show the operational characteristic of PMSG type WPGS under the transient phenomenon of utility.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.642-643
• /
• 2007

본 논문은 우리 전력연구원에서 보유하고 있는 실시간 시뮬레이터(RTDS)를 이용하여 산학연을 대상으로 하여 개발된 교육, 훈련 시스템 중 하나의 아이템인 변압기 과도현상 훈련코스데 대해 소개하고자 한다. 실계통 현장에서 자주 발생하는 변압기 내부고장을 RTDS/RSCAD 상에서 구현하여 변압기 과도특성을 파악한 후 계통해석에 이용하고, 변압기 돌입전류 현상과 포화현상 모의를 통하여 변압기 과도현상에 대해 명확히 이해할 수 있도록 하는데 본 훈련코스의 목적이 있다. 우리 전력연구원은 2002년부터 산학연을 대상으로 실시간 시뮬레이터 응용 계통해석 교육을 여러차례 시행해 오고 있으며, 2007년 3월 교육, 훈련 시스템 구축이 완료됨에 따라 앞르로 정기적인 교육을 시행할 예정이다.