• Proceedings of the KIEE Conference
• /
• 2007.11b
• /
• pp.103-105
• /
• 2007

최근에 와서 유가상승, 화석에너지의 고갈문제, 환경 문제로 인해 분산전원에 대한 관심이 높아지는 추세에 있다. 소형 원자력을 동력으로 하는 전력시스템은 열병합발전과 같이 전기와 열을 동시에 생산하며, 분산전원 및 도서지역의 지역 에너지시스템으로 적용 가능한 다목적 에너지시스템이다. 본 논문은 소동력로가 울릉도 계통에 미치는 영향을 모의하였고, 모의를 위해 PSS와 RTDS를 사용하였다. 또한 울릉도 내의 디젤반전기와 소동력로의 전기적 특성을 비교 검토하여, 지역 에너지시스템의 유용성을 확인하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.95-104
• /
• 2003

The electric traction systems are quite differ from general power systems which is single-phase and heavy load. Therefore, there are inevitably power quality problems such as steady state or transient voltage drop, voltage imbalance and harmonic distortion. Among these problems, since steady-state volatge drop is the one of most important factor in electric power quality, many researches about on the compensation of volatge drop by using SVC(Static Var Compensator) and/or STACOM(Static Compensator) have been studied and proposed Also, it is expected that transient voltage drop(voltage sag) could affect the control and safety of high speed traction load. In this paper, voltage sag compensation of AT(Auto Transformer) feeding system are studied The detailed transient models of utility source, scott transformer, AT, and traction load are estabilished. The application of DVR(Dynamic Voltage Restorer) in electric traction system is proposed to compensate the voltage sag of traction network which is occured by the fault of utility source. It can be shown that application of the DVR in electric traction system is very useful to compensate the volatge sag from the result of related simulation works.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.3
• /
• pp.1288-1295
• /
• 2012

Korea Ministry of Knowledge Economy has estimated that wind power (WP) will be occupied 37% in 2020 and 42% in 2030 of the new energy sources, and also green energies such as photovoltaic (PV) and WP are expected to be interconnected with the distribution system because of Renewable Portfolio Standard (RPS) starting from 2012. However, when a large scale wind power plant (over 3[MW]) is connected to the traditional distribution system, protective devices (mainly OCR and OCGR of re-closer) will be occurred mal-function problems due to changed fault currents it be caused by Wye-grounded/Delta winding of interconnection transformer and %impedance of WP's turbine. Therefore, when Double-Fed Induction Generator (DFIG) of typical WP's Generator is connected into distribution system, this paper deals with analysis three-phase short, line to line short and a single line ground faults current by using the symmetrical components of fault analysis and PSCAD/EMTDC modeling.

• Science of Emotion and Sensibility
• /
• v.7 no.4
• /
• pp.51-56
• /
• 2004

This study was to estimate human response to different color light stimulation by measuring physiological parameters of human behavior, For both stimulations we used color lights with 6 color filters such as red, yellow, green, blue, violet, and white. The experiment was performed in a soundproof chamber. 30 young male and female subjects participated in the experiment, For physiological parameters, we measured electroencephalogram (EEG), electr ocardiogram (ECG). The result of EEG analysis showed that the relative power of $\alpha$ wave ratio increased in blue and green, In case of HRV spectrum analysis, HF/LF ratio increased in green and blue. From these results, we knew that the physical response was affected by color environment and it might be an indicator in the design of a color environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.7
• /
• pp.52-58
• /
• 2012

In this study, we have investigated the effect of the solar power generation facilities on the power quality of interconnected solar power generation system. When the solar power generation facility was connected to the distribution system, whether the solar power generation is under operation or not, Peak factor of current was increased to 0.033[%], Frequency is deviated from $60{\pm}0.2$[Hz] and also Short term flicker indication($P_{st}$) increased to 0.213[p.u.] compare with the disconnected situation. Harmonic current [%] in orders was 11.42[%] maximum under 11th orders and was 7.861[%] between 11th and 17th orders. These values were about 3 or 4 times compared with "the power system interconnection technique standards" at the same situation above. Therefore, we could confirmed that the solar power generation facility, when it was connected to the existing distribution system, made bad influence on the power qualities such as the peak factor of current, frequency regulation, short term flicker indication($P_{st}$) and harmonic current [%] in orders etc.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.2
• /
• pp.810-818
• /
• 2021

A leakage current of ESS is classified mainly by the occurrence from a PCS(Power Conditioning System) section and an unbalanced grid current. The reason for the leakage current from the PCS section is a voltage change by IGBT (Insulated Gate Bipolar Transistor) switching and stray capacitance between the IGBT and heatsink. The leakage current caused by the grid unbalanced current flows to the ESS through the neutral line of grid-connected transformer for the ESS with a three limb iron type of Yg-wire connection. This paper proposes a mechanism for the occurrence of leakage current caused by stray capacitance, which is calculated using the heatsink formula, from the aspect of the PCS section and grid unbalance current. Based on the proposed mechanisms, this study presents the modeling of the leakage current occurrence using PSCAD/EMTDC S/W and evaluates the characteristics of leakage currents from the PCS section and grid unbalanced current. From the simulation result, the leakage current has a large influence on the battery side by confirming that the leakage current from the PCS is increased from 7[mA] to 34[mA], and the leakage current from an unbalanced load to battery housing is increased from 3.96[mA] to 10.76[mA] according to the resistance of the housings and the magnitude of the ground resistance.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1999.10a
• /
• pp.169-169
• /
• 1999

최근 산업 플랜트의 공정제어 시스템은 복잡하고 대규모화되어 고장 발생시 경제적 손실과 위험성이 증폭되어 규정된 안정서와 신뢰성 확보가 필수적이라 할 수 있다. 고장검출 및 진단기법은 시스템의 신뢰성을 높이기 위한 효과적인 방안을 연구하는 것으로 현대에 들어서 많은 학자들의 관심을 끌고 있으며 실제 계통에 점차적으로 응용되고 있다. 현재까지 개발된 고장검출 및 진단기법은 사용된 프로세스 모델의 형태, 고장검출 진단 알고리즘에 따라 다양하게 분류 될 수 있으며 일반적으로 사용된 모델에 따라 크게 1) 정량적 모델에 근거한 해석적 기법, 2) 정성적 모델에 근거한 기법, 3) 지식기반 진단 기법으로 구분 할 수 있다. 이중 정량적 모델 기법은 대상계통의 수학적 모델에 근거하여 운전 데이터를 분석함으로서 고장검출 진단을 수행하는 해석적 기법으로서 근본적으로 계통의 정확한 수학적 모델을 요구하므로 불확실성을 포함한 계통 및 비선형성이 강한 계통등에는 적용이 곤란하다. 정성적 모델 및 지식기반 기법은 정량적 진단 기법과는 달리 대상 프로세스에 대한 수학적 모델 대신에 운전자의 경험과 프로세스 변수간의 상호 작용 및 고장의 전파과정, 고장원인과 증상과의 직접적인 관계에 대한 구조적 지식에 근거한 것으로 고장원인에 대한 계통의 동작을 추론 할 수 있으며, 상황 변화에 따른 영향을 예측할 수 있다. 본 논문에서는 정성적 모델 및 지식기반 기법에 근거한 고장검출 및 진단 기술을 화력 발전소 보일로 프로세스에 적용하여 정성적 시뮬레이션에 의한 설비의 고장을 조기에 발견하여 고장 파급으로 인한 발전 정지 및 설비의 손상 확대를 방지하고 고장 발생시 신속한 원인 규명 및 후속 조치관련 정보들을 운전원에게 제공할 목적으로 현재 전력원에서 개발중인 지능형 경보시스템에 대하여 기술하고자 한다.음과 같이 설명하였다. 서로 상반되는 것들이 다음과 같이 설명하였다. 서로 상반되는 것들이 부딛힘이 없이 공존하고 일상의 논리가 무시된다. 부정, 의심이 없고 확실한 것이 없다. 한 대상에 가졌던 생각이 다른 대상에 옮겨간다(displacement). 한 대상이 여러 대상이 갖고 있는 의미를 함축하고 있다(condensation). 시각적인 순서가 무시된다. 마음속의 생각과 외부의 실제적인 일을 구분하지 못한다. 시간 상의 순서가 있다가 없다가 한다. 차례로 일어나야 할 일이 동시에 한꺼번에 일어난다. 대상들이 서로 비슷해지고 동시에 있을 수 없는 대상들이 함께 나타난다. 사고의 정상적인 구조가 와해된다. Matte-Blance는 무의식에서는 여러 독립된 대상들간의 구분을 없애며, 주체와 객체를 하나로 보려는 대칭화(symmetrization)의 경향이 있기 때문에 이런 변화가 생긴다고 하였다. 또 대칭화가 진행되면 무한대의 느낌을 갖게 되어, 전지(moniscience), 전능(omnipotence), 무력감(impotence), 이상화(idealization)가 나타난다. 그러나 무의식에 대칭화만 있는 것은 아니며, 의식의 사고양식인 비대칭도 어느 정도 나타나며, 대칭화의 정도에 따라, 대상들이 잘 구분되어 있는 단계, 의식수준의 감정단계, 집단 내에서의 대칭화 단계, 집단간에서의 대칭화 단계, 구분이 없어지는 단계로 구분하였다.systems. We believe that this taxonomy is a significant contribution because it adds clarity, completeness, and "global perspective" to workflow architectural discussions. The vocabulary suggested here

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.3
• /
• pp.201-208
• /
• 2015

The effects of dead-time and offset error, which cause output current distortion in single-phase grid-connected inverters are investigated this paper. Offset error is typically generated by measuring phase current, including the voltage unbalance of analog devices and non-ideal characteristics in current measurement paths. Dead-time inevitably occurs during generation of the gate signal for controlling power semiconductor switches. Hence, the performance of the grid-connected inverter is significantly degraded because of the current ripples. The current and voltage, including ripple components on the synchronous reference frame and stationary reference frame, are analyzed in detail. An algorithm, which has the proportional resonant controller, is also proposed to reduce current ripple components in the synchronous PI current regulator. As a result, computational complexity of the proposed algorithm is greatly simplified, and the magnitude of the current ripples is significantly decreased. The simulation and experimental results are presented to verify the usefulness of the proposed current ripple reduction algorithm.

• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.214-216
• /
• 2000

This paper presents an comparative study on the effect of STATCOM and UPFC to the power system static analysis. The effect of STATCOM can be analyzed with PSS/E program which is generally used in power system analysis, while UPFC model for static analysis is not provided yet. Thus, UPFC is equivalently represented as a synchronous condenser and load, while the active and reactive power of the specific transmission line and the voltage of the bus is controlled appropriately. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to control the bus voltage than STATCOM, because UPFC can control not only the bus voltage where the parallel inverter is installed but also the active and reactive power flow in the transmission line where the series inverter is installed.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.155-157
• /
• 2001

This paper presents an comparative study on the effect of SSSC and UPFC to the power system static analysis. SSSC is used to control active power flow in transmission lines by controlling the phase angle of the injected voltage source which is in rectangular to the line current. UPFC is used to control the magnitude and phase of the injected voltage sources which are connected both in series and in parallel with the transmission line to control power flow and bus voltage. To compare the effect of SSSC and UPFC in power system static analysis, the PSS/E simulation program is used. As the FACTS device model such as SSSC and UPFC is not provided in PSS/E yet, an equivalent load model is used. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to improve bus voltage than SSSC in power system static analysis.