• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.228-228
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• 2002

The DLS(Data Link System) is located in the PDTS(Payload Data Transmission Subsystem) of KOMPSAT-II, and its main function is to provide communication link with Ground Segment as a space segment. DLS receive the data of MSC, OBC from DCSU(Data Compression Storage Unit) and transmit to the Ground Station by X-Band RF link. DLS is consist of CCU(Channel Coding Unit), QTX(QPSK Transmitter, ASU(Antenna Switch Unit) CCU makes a packet for communication after several kind of data processing such like Ciphering, RS Coding. QTX transmit PDTS data by OQPSK. Modulation. ASU is the unit for reliability of antenna switching. So, DLS's function is consists of ciphering, RS coding, CCSDS packetizing, randomizing, modulation and switching to antenna. These DLS's functions are controlled by PMU(Payload Management Unit). All commands to DLS are sent by PMU and all telemetries of DLS are sent to the PMU. The PMU receives commands from OBC and sends telemetries to the OBC. The OBC communicates with Ground Station by S-Band RF link. This paper presents the on-orbit DLS operation concept through the ground segment.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.593-596
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• 2005

The MSC is a remote sensing instrument with very high performance that is to be installed on KOMPSAT2 satellite. The MSC consists of EOS (Electro-Optic Subsystem), PMU (Payload Management Unit) and PDTS (Payload Data Transmission Subsystem). PMU controls and monitors all the other payload units by sending commands and collecting telemetry. PMU is in charge of interfacing between payload system and satellite bus system. PMU gets commands from ground-station via OBC (On-Board Computer) that is a main controller of the satellite bus system and sends telemetry to the ground-station via OBC. There is a processor module, called SBC (Single Board Computer) in the PMU. The SBC is a main controller of the MSC system. The main roles of the SBC are payload mission management, command validation and execution, telemetry collection and monitoring, ancillary data handling, event reporting, power control of payload sub-units and communication with these units. Intel's 80486DX2 processor has been used for the SBC. Due to the fact that the SBC plays important roles for imaging mission execution and handles a lot of control data that is required for payload operation, it is required to make analysis of the CPU load when it is in maximum operation mode. In this paper, the analysis and measurement results of the SBC throughput in the maximum operation mode.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.218-219
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• 2011

한전계통에서는 대규모 발전단지 인출 송전선로 고장 시발전기 과도 안정도 향상을 위한 발전기 제어 대책을 수립하여 운영하고 있다. 이러한 대책을 SPS(Special Protection System)이라고 한다. SPS는 인출 송전선로 고장정지에 따른 과도안정도 평가를 오프라인을 통하여 사전에 모의 분석하여 수립된다. 그러나 대상 계통은 보수적 운영을 위해 가장 가혹한 조건을 선정하여 검토한다. 그러나 차단 대수는 검토 대상 계통에 따라 달라질 수 있다. 그래서 필요한 기술이 실시간과도안정도 평가 기술이다. 본 논문에서는 PMU기반의 실시간 과도 안정도 평가시 고려해야할 사항에 대하여 검토하였다.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.451-456
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• 2009

Through the development of phasor measurement units (PMU), various aspects of power system dynamic behavior could be monitored and diagnosed. Monitoring dynamic voltage stability has become one of the achievements we can obtain from PMUs. It is very important to select the most appropriate method for the Korea Electric Power Corporation (KEPCO) system since there are many voltage stability indices. In this paper, we propose an advanced WAVI (Wide Area Voltage Stability) that is well suited for the purposes of monitoring the dynamic voltage stability of KEPCO's PMU installation plan. The salient features of the proposed index are: i) it uses only PMU measurements without coupling with EMS data; ii) it is computationally unburdened and can be applied to real-time situations. The proposed index is applied to the KEPCO test system and the results show that it successfully predicts voltage instability through comparative studies.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.193-195
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• 2005

전력계통의 안정적인 운용을 위해서는 현재 운전 중인 계통의 운용데이터를 수집하여 분석하고 그에 따라 적절한 제어를 하는 것이 매우 중요한 일이다. EMS가 이러한 일을 처리하고 있으며, 여기서 상태추정기는 정확한 계통 운용 데이터베이스를 제공하는 역할을 한다. 지금까지 모든 데이터는 동시에 측정이 되었다는 가정 하에 상태추정 연산을 하였으나, 실제로 모든 데이터 측정의 동기성을 확보하는 것은 사실상 불가능하다. 최근 인공위성에 의해 동기화된 PMU(phasor measurement unit)가 전력계통 운용에 사용되고 있다. 본 논문에서는 PMU로부터 얻을 수 있는 전압 및 전류 데이터를 상태추정에 이용하는 방법을 개발하였다. 위성에 의해 동기화된 페이저 측정데이터는 데이터 측정의 동기성 확보뿐만 아니라, 데이터의 정밀도 및 위상각의 직접적인 측정이라는 둥의 여러 가지 면에서 매우 효용성이 높은 데이터이다. 본 연구를 통해 개발된 상태추정 프로그터은 IEEE 30모선 시험계통을 이용하여 그 타당성을 검증하였다.

• JOURNAL OF ELECTRICAL WORLD
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• s.397
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• pp.51-51
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• 2010

• Defense and Technology
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• no.7 s.209
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• pp.38-45
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• 1996

• Defense and Technology
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• no.8 s.210
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• pp.46-55
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• 1996

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1387-1392
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• 2012

These days people use a lot of electric power, because industry advancement and a standard of living is elevated. So voltage stability analysis and control problems are very important in these days. U.S.A has already developed voltage stability analysis program, and use it on power transmission scheme such as generator overhaul, transmission line off and so on. So voltage stability analysis is more and more interested in Korea, too. In this paper, we introduce a standard theory of voltage stability analysis and real time voltage stability analysis program that use sPMU(Satellite Phasor Measurement Unit). And we also introduce the calculation result about voltage stability in Jeju power transmission system.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.643-652
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• 2021

Accidents or faults in the transmission and distribution system are never completely avoidable, and short-circuit and earth faults are occurs despite the efforts of the TSO and DSO. Recently, the connection to the transmission and distribution system of large-capacity new and renewable distributed power has increased rapidly and has various effects on the operation of the system. In order to minimize this, connection standards such as FRT (Fault-Ride-Through) have been established to provide wind turbines or solar inverters. In the event of a major faults of the power system, the operation support shall be provided so that the operator can stably operate the system by smoothly performing connection maintenance or rapid system separation. In this paper, in order to appropriately determine whether the FRT condition, which is the grid connection criterion for a representative DERs, is sufficient, a detection system using a PMU (Phasor Measurement Unit) that measures a synchro-phasors was designed and deployment and a system accident due to a generator step-out to analyze and evaluate the proposed system based on the case.