• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.382-384
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• 2008

D-TRS is a method of wireless communication. This method will be able to use several frequency for multiple user used chanel together. TETRA of D-TRS technology is not rented network. Using TETRA network has the strong point which cost better than CDMA network of rental network. Master server of SCADA(Supervisory Control And Data Acquisition) system is realtime supervise control and a data acquire the control system or the RTU(Remote Terminal Unit). The present paper is developed and proposal the gateway platform for electronic power backbone network based on D-TRS. This gateway platform is converted DNP3.0 messages with TETRA PDU and converted TETRA PDU with DNP3.0 messages. Master server and FRTU will be able to send and receive DNP3.0 message via TETRA network using this gateway platform.

• Journal of Power Electronics
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• 제14권4호
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• pp.671-677
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• 2014

In this paper, a new basic unit is proposed. Then, a cascaded multilevel inverter basded on the series connection of n number of these new basic units is proposed. In order to generate all of the voltage levels (even and odd) at the output, three different algorithms to determine the magnitude of the dc voltage source are proposed. Reductions in the number of power switches, driver circuits and dc voltage sources in addition to increases in the numbr of output voltage levels are some of the advantages of the proposed cascaded multilevel inverter. These results are obtained through a comparison of the proposed inverter and its algorithms with an H-bridge cascaded multilevel inverter from the point of view of the number of power electronic devices. Finally, the capability of the proposed topology with its proposed algorithms in generating all of the voltage levels is verified through experimental results on a laboratorary prototype of a 49-level inverter.

• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.255-260
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• 2018

In recent years, increasing electricity use has led to considerable interest in green energy. In order to effectively supply, cut off, and operate an electric power system, many electric power facilities such as gas insulation switch (GIS), cable, and large substation facilities with higher densities are being developed to meet demand. However, because of the increased use of aging electric power facilities, safety problems are emerging. Electromagnetic wave and leakage current detection are mainly used as sensing methods to detect live-line partial discharges. Although electromagnetic sensors are excellent at providing an initial diagnosis and very reliable, it is difficult to precisely determine the fault point, while leakage current sensors require a connection to the ground line and are very vulnerable to line noise. The partial discharge characteristic in particular is accompanied by statistical irregularity, and it has been reported that proper statistical processing of data is very important. Therefore, in this paper, we present the results of analyzing ${\Phi}-q-n$ cluster distributions of partial discharge characteristics by using K-means clustering to develop an expert partial discharge diagnosis system generated in a GIS facility.

• 전력전자학회논문지
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• 제15권4호
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• pp.266-273
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• 2010

태양광 인버터(PCS)는 태양전지에서 발생된 전력을 계통에 연계시키는 장치이다. IEEE 1547 규격에 따르면 PCS에서 발생되는 고조파왜곡은 5% 이내여야만 한다. 일반적으로 PCS에서 계통으로 유입되는 고조파 검출은 전용 계측장치에 의해서 측정된다. 초기에 규격에 맞게 설계된 PCS의 고조파가 소자들의 노화나 제어기 고장에 의해 증가하게 될 경우 발전을 중지하거나 경보를 발생시켜야 한다. 기존의 상용화된 시스템에는 이러한 기능이 존재하지 않는다. 본 연구에서는 PCS 내부에 고조파왜곡을 실시간으로 측정하는 알고리즘을 내장시키는 방법에 대해 연구한다. 고성능 32-bit 부동소수점 DSP를 이용한 PCS를 제작하고 256-point DFT(Discrete Fourier Transform) 알고리즘을 이용하여 1[ms] 이내에 하모닉 계수를 계산하였다. 제어기 제작에 대한 설명과 실험 결과로서 연구의 타당성을 입증하였다.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1305-1309
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• 2013

The application of the superconducting fault current limiter (SFCL) in a power distribution system is expected to contribute the voltage-sag suppression of the bus line as well as the fault-current reduction of the fault line. However, the application effects of the SFCL on the voltage sag of the bus line including the fault current are dependent on its application location in a power distribution system. In this paper, we investigated the fault current limiting and the voltage sag suppressing characteristics of the SFCL due to its application location such as the outgoing point of the feeder, the bus line, the neutral line and the 2nd side of the main transformer in a power distribution system, and analyzed the trace variations of the bus-voltage and fault-feeder current. The simulated power distribution system, which was composed of the universal power source, two transformers with the parallel connection and the impedance load banks connected with the 2nd side of the transformer through the power transmission lines, was constructed and the short-circuit tests for the constructed system were carried out. Through the analysis on the short-circuit tests for the simulated power distribution system with the SFCLs applied into its representative locations, the effects from the SFCL's application on the power distribution system were discussed from the viewpoints of both the suppression of the bus-voltage sag and the reduction of the fault current.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2737-2743
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• 2015

풍력발전은 풍력단지가 전력계통과 접속되는 모선의 전압을 유지 또는 제어하기 위한 충분한 무효전력을 공급할 수 있어야 한다. 하지만 풍력단지와 계통 접속점(POI - Point of Interconnection) 모선을 연결하는 선로의 무효전력 손실 때문에 풍력터빈의 무효전력공급은 접속점의 전압을 제어하기에는 불충분하다. 이 문제는 접속점에 STATCOM(Static Synchronous Compensator)과 같은 부수적인 무효전력 보상장치를 설치하여 해결할 수 있다. 본 논문에서 제시하는 STATCOM과 Switched-Shunt, 탭변환 변압기와 같은 기존의 무효전력 보상장치의 협조제어를 사용하면 더욱 효과적으로 접속점 모선의 전압을 제어할 수 있다. 본 논문에서 제시한 방법을 이용하여 초기부하에 대하여 임의의 부하 변동률을 가지는 모의 시스템에 적용한 결과 접속점 모선의 전압강하는 60%이상 개선되었고 부하 모선의 전압은 정격전압의 95%이상을 유지하였다.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.53-64
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• 2024

울산인근을 중심으로 한 영남 남동부 지역은 대규모 부유식 해상풍력이 계획되어 있으며 원자력발전소의 신설과 기존 원자력발전소의 수명연장 등에 따라 전력망의 확충이 요구되고 있다. 정부에서는 10차 전력수급계획에 따라 이 지역의 전력계통 신설계획을 발표하였으나 경주 인근의 국립공원과 문화재 보호구역을 경과함에 따라 실제 건설단계에 어려움이 많을 것으로 예상된다. 이에 따라 본 연구에서는 기존 선로를 활용하고 신설을 최소화하는 방안을 제시하고 이 계통에 대해 PSS/E를 활용하여 과도안정도를 분석하여 타당성을 입증하였다.

• 한국산학기술학회논문지
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• 제16권6호
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• pp.4115-4120
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• 2015

풍력단지가 연계된 전력계통의 과도안정도를 보장하기 위해서는 전력계통과 풍력단지의 접속점에 풍력발전기가 충분한 무효전력을 공급할 수 있어야 한다. 하지만 개별의 풍력터빈은 안정도를 유지하기 위한 충분한 무효전력 공급능력을 가지지 못한다. 또한 풍력단지와 접속점 사이의 케이블은 리액턴스가 크고 이에 따른 무효전력 손실도 크다. STATCOM(Static Synchronous Compensator)은 고속으로 동작할 수 있고 충분한 무효전력을 공급할 능력을 가지고 있기 때문에 과도안정도를 향상시킬 수 있다. 본 논문에서는 풍력단지가 연계된 전력계통의 과도안정도 향상에 있어서 STATCOM의 유효성을 보인다. 접속점에 STATCOM을 설치하고 동적 모의를 한 결과 과도 안정도가 향상되는 결과를 얻을 수 있었다.

• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.43-48
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• 2022

Although the distribution system has been structured as complicated as a mesh in the past, the connection points for each line are always kept open, so that it is operated as a radial distribution system (RDS). For RDS, the line utilization rate is determined according to the maximum load on the line, and the utilization rate is usually kept low. In addition, when a fault occurs in the RDS, a power outage of about 3 to 5 minutes occurs until the fault section is separated, and the healthy section is transferred to another line. To improve the disadvantages of the RDS, research on the construction of a networked distribution system (NDS) that linking multiple lines is in progress. Compared to the RDS, the NDS has advantages such as increased facility utilization, load leveling, self-healing, increased capacity connected to distributed generator, and resolution of terminal voltage drop. However, when a fault occurs in the network distribution system, fault current can flow in from all connected lines, and the direction of fault current varies depending on the fault point, so a high-precision fault current direction determination method and high-speed communication are required. Therefore, in this paper, we propose an accurate fault current direction determination method by comparing the peak value polarity of the fault current in the event of a fault, and a communication-based protection coordination method using this method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.140-144
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• 1988

This paper describes requirements for cogenerating in parallel with utility. Cogenerating is the simultaneous generation of energy in two or more forms, usally electricity and heat. Cogeneration is most energy efficient when generating in paralled will the electric utility, but requires proper control and protection. When onsite generation and utility systems are operated in parallel, there are many factors. such as operation mode. point of connection, grounding, synchronizalion. protective relaying, metering, and the like, that must be considered to provide safe and efficient operation.