• Title/Summary/Keyword: medium voltage (MV) line

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Impedance measurement and analysis of overhead medium voltage power lines for broad band power line communication (BPLC) ($1{\sim}30MHz$ 광대역 전력선 통신을 위한 고압 배전선의 임피던스 특성 측정 및 해석)

  • Park, Young-Jin;Lee, Jae-Jo;Kim, Kwan-Ho;Lee, Won-Tae
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2345-2347
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    • 2005
  • In this paper, impedance characteristics of overhead medium-voltage (MV) power lines is reported for power line communication (PLC) over an MV power line network. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the transmission line theory, reflection behavior and impedance of power lines are investigated. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power lines is between $200{\Omega}$ and $300{\Omega}$ and converges to a half of their characteristic impedance.

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Impedance Characteristics of Overhead Medium-Voltage Power lines for Power Line Communication (전력선통신을 위한 고압 배전선로의 임피던스 특성)

  • Chun Dong-wan;Park Young-jin;Kim Kwan-ho;Shin Chull-chai
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.11
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    • pp.67-78
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    • 2005
  • In this paper, impedance characteristics of overhead medium-voltage (MV) power line for power line communication (PLC) is analyzed. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the equivalent model and basic transmission line theory, input impedance at the signal induction part is calculated. And also calculated input impedance of power line itself that the medium voltage coupler and coaxial cable effect are removed. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power line itself is between $200\;{\Omega}\;and\;300\;{\Omega}$ and converges to a half of their characteristic impedance with increasing frequency. And also measured data is very similar to calculated data.

Development of Signal Coupler for Power Line Communication over Medium Voltage Distribution Line (고압 배전선로 전력선 통신 신호결합장치 개발)

  • Lee Jae-Jo;Park Young-Jin;Oh Hui-Myoung;Kim Kwan-Ho;Lee Dae-Young
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.6
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    • pp.409-416
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    • 2005
  • For broadband high-data-rate power line communication with the allocated frequency bandwidth from 2 to 30 MHz on medium voltage (MV) distribution power lines, a signal coupling unit is developed. The coupling unit is composed of a coupling capacitor for coupling communication signal, a drain coil, and an impedance matching part. The coupling capacitor made of ceramic capacitor is designed for transmission property of better than 1 dB in the frequency range. The drain coil is used for preventing low frequency high voltage from junction of medium voltage power line in case that a coupling capacitor is not working properly any more. Also, using ferrite core, a novel broadband impedance matching transformer is developed. A complete coupling unit with a coupling capacitor, a drain coil, and a matching transformer is housed by polymer for good isolation and distinguishing from high voltage electric facilities. Each is fabricated and its frequency behavior is tested. Finally, complete signal couplers are equipped in a MV PLC test bed and their performance are measured. The measurement shows that the coupling capacitor works excellently.

Field Trial of Power Line Communication Access Network over Medium Voltage Power Distribution Grid (고압 배전선로를 이용한 고속 전력선 통신 가입자망 구축 연구)

  • Lee, Jae-Jo;Oh, Hui-Myoung;Park, Young-Jin;Kim, Kwan-Ho;Lee, Dae-Young
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.3040-3042
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    • 2005
  • During the last several years, interest in broad-band power line communications (PLC) has been grown over medium voltage(MV) power distribution lines as well as low voltage lines. This paper introduces a medium voltage PLC test field that is set up in the suburbs of Euiwang city in Korea. This test field could be used not only for the measurement of communication channel environment but also for internet service. This paper shows the configuration of medium voltage test field with network devices like MV signal coupler and the results of channel environment like noise and impulse response. It also shows the service performance of PLC access network through network management system.

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Characteristics on the Neutral Point Potential of Line-to-Ground Voltage according to Line-to-Ground Fault in Resistance Ground System for Ships (선박의 저항접지 시스템에서 지락 고장에 따른 대지전압 중성점 전위 특성)

  • Lee, Yun-Hyung;Ryu, Ki-Tak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.689-696
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    • 2018
  • System grounding is applied to the neutral point of a power source to secure the from any abnormal voltage and/or grounding fault. System grounding, which is applied mainly in ships is an ungrounded and resistance grounded system. Vessels using the MV power system with 3.3kV, 6.6kV, and 11kV mainly adopt a high resistance grounding system among the resistance grounding systems. The ground fault accounts for 95% of all faults occurring in the electrical system and when a fault occurs, the line-to-ground voltage of the power system is increased excessively, which adversely affects the onboard insulation system. This study analyzed the variation characteristics of the line-to-ground voltage neutral point according to the degree of ground fault in a resistance ground system applied in vessels. For this purpose, the characteristics of the grounding system were first explained, and the modeling of the neutral point potential of the line-to-ground voltage of the resistance grounding system in the vessels was derived. Finally, this study examined how the line-to-ground voltage, line voltage, and neutral point change according to various variable environments through MATLAB simulations.

A Study on Methods of Interference Avoidance between Power Line Communications and Radio Communications (고속전력선통신과 무선통신간의 간섭 회피 방법에 대한 연구)

  • Jang, Dong-Won;Lee, Young-Hwan
    • 한국정보통신설비학회:학술대회논문집
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    • 2007.08a
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    • pp.223-226
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    • 2007
  • This paper first outlines the technology used in Power Line Communications(PLC) systems, and the political support being offered to the technology, from the point of view of its effect on electromagnetic compatibility (EMC). The radio spectrum needs protection from other interferers, and there is a regime in place to provide this interference avoidance/mitigation. Nevertheless, PLC has several features that mean that it is capable of creating such interference. These features are discussed, and some published field trial results are reviewed. Difficulties in achieving compatibility between the requirements for radio protection and the requirements for operation of the PLC system mean that there is no consensus as yet as to how PLC system components can be made compliant with EMC requirements. It is concluded that there is little prospect of an accommodation between the competing demands, so that if PLC is to become widespread it will be at the expense of the radio environment.

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Analysis and Control of a Modular MV-to-LV Rectifier based on a Cascaded Multilevel Converter

  • Iman-Eini, Hossein;Farhangi, Shahrokh;Khakbazan-Fard, Mahboubeh;Schanen, Jean-Luc
    • Journal of Power Electronics
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    • v.9 no.2
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    • pp.133-145
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    • 2009
  • In this paper a modular high performance MV-to-LV rectifier based on a cascaded H-bridge rectifier is presented. The proposed rectifier can directly connect to the medium voltage levels and provide a low-voltage and highly-stable DC interface with the consumer applications. The input stage eliminates the necessity for heavy and bulky step-down transformers. It corrects the input power factor and maintains the voltage balance among the individual DC buses. The second stage includes the high frequency parallel-output DC/DC converters which prepares the galvanic isolation, regulates the output voltage, and attenuates the low frequency voltage ripple ($2f_{line}$) generated by the first stage. The parallel-output converters can work in interleaving mode and the active load-current sharing technique is utilized to balance the load power among them. The detailed analysis for modeling and control of the proposed structure is presented. The validity and performance of the proposed topology is verified by simulation and experimental results.

Design of low-power OTP memory IP and its measurement (저전력 OTP Memory IP 설계 및 측정)

  • Kim, Jung-Ho;Jang, Ji-Hye;Jin, Liyan;Ha, Pan-Bong;Kim, Young-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.11
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    • pp.2541-2547
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    • 2010
  • In this paper, we propose a design technique which replaces logic transistors of 1.2V with medium-voltage transistors of 3.3V having small off-leakage current in repetitive block circuits where speed is not an issue, to implement a low-power eFuse OTP memory IP in the stand-by state. In addition, we use dual-port eFuse cells reducing operational current dissipation by reducing capacitances parasitic to RWL (Read word-line) and BL (Bit-line) in the read mode. Furthermore, we propose an equivalent circuit for simulating program power injected to an eFuse from a program voltage. The layout size of the designed 512-bit eFuse OTP memory IP with a 90nm CMOS image sensor process is $342{\mu}m{\times}236{\mu}m$. It is confirmed by measurement experiments on 42 samples with a program voltage of 5V that we get a good result having 97.6 percent of program yield. Also, the minimal operational supply voltage is measured well to be 0.9V.

Partial Discharge Measurement of Power Cables for Nuclear Power Plant (원자력발전소 전력케이블 부분방전 진단 사례)

  • Ha, Che-Wung;Ju, Kwang-Ho;Lim, Woo-Sang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1632-1638
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    • 2011
  • Electric cables are one of the most important components in a nuclear power plant since they provide the power needed to operate electrical equipment. Despite their importance, cables typically receive little attention since they are considered passive, long-lived components that have been very reliable over the years when subjected to the environmental conditions for which they were designed. The operating experience reveals that a defect of the insulator or poor construction causes the initial failure of cable. However, the number of cable failures increase with plant aging, and these cable failures are occurring within the plants' 40-year licensed period. These cable failures have resulted in plant transients, shutdown, loss of safety functions or redundancy, entries into limiting conditions for operation, and challenges for plant operators. Therefore, diagnosis of MV cable installed in NPPs has become one of the most urgent issues in recent years. In accordance with PSR, condition maintenance for cables is also continuously required. Recently, HFPD tests have been widely performed to diagnose cable in the transmission and distribution cable system. However, on-line HFPD wasn't used in the NPPs because of the danger of plant shutdown, measurement sensitivity and application problems, etc. In this paper, HFPD measurement with portable device was performed to evaluate the integrity of the 4.16kV & 13.8kV cable lines. The test results show that HFPD is highly attractive to the diagnosis of MV cables in NPP by high detection sensitivity on-site.