• Title/Summary/Keyword: Switching Surge

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A Study on the Measuring System of the Switching Surges in the 22.9 kV Distribution Lines (22.9 kV 배전용 계폐기의 개폐서지 측정시스템 구성에 관한 연구)

  • Park, Sang-Man;Yoon, Tae-Sang;Roh, Hwang-Nai;Han, Yong-Hee;Lee, Heung-Ho
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.3094-3096
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    • 2000
  • In the distribution systems, there are generally two sources of transient over-voltages. One is the capacitor switching surge and the other is the lightning surge. This paper is written about the measuring and analysis of switching over-voltages in the 22.9 kV multi-grounded distribution systems. The measurement was performed in the Kochang distribution test line in January, 2000.

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Detailed Study on Insulation Coordination of a 25kV Power System Connected with a VCB and Transformer

  • Baek, Byung-San;Kim, Yong-Han
    • Journal of Electrical Engineering and Technology
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    • v.12 no.3
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    • pp.1245-1249
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    • 2017
  • Recently, unusual transformer failures have been reported in 25kV power systems connected with a VCB and transformer. In this study, performance of the protection system, dielectric strength of the transformers, characteristics of switching surges and resonance phenomena were analysed and assessed. All investigations regarding the insulation breakdown of the transformers were carried out by simulations, laboratory tests, factory tests and on-site measurements in order to thoroughly investigate the root causes. Furthermore, experimental methods for investigating the resonance phenomenon were derived and tests were conducted applying the derived method to recreate the phenomenon in the transformer. It is found that resonance between the transformer and switching surge generated by closing a VCB can initiate the breakdown of internal windings of a transformer.

Analysis of Switching Surge Over-voltage in AC/DC Hybrid Transmission Lines (AC/DC 병가선로의 개폐서지 과전압 해석)

  • Yoo, Seong-Soo;Shin, Koo-Yong;Moon, Chae-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.3
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    • pp.459-466
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    • 2022
  • Switching surges are a common type of phenomenon that occur on any sort of power system network. These are more pronounced on long transmission lines and in high voltage converter stations. At AC/DC hybrid transmission lines, the insulation coordination of such lines is mainly dictated by the peak level of switching surges, the most dangerous of which include three phase line energization and AC/DC converter station. The power system structure consist of AC/DC hybrid transmission lines which is combination of AC 765kV and ±500kV HVDC 1 bipole system for contingency analysis. The power system under study and its components are simulated using EMTDC software package, the effects of the various AC/DC mixing power lines are reviewed. The developed models of EMTDC conversion lines based on combination of AC/DC system are simulated and the characteristics of switching surge over-voltage from its results are discussed.

A study on the Conducted Noise Reduction in Random PWM (Random PWM 기법을 이용한 전도노이즈 저감)

  • Jeong, Dong-Hyo
    • Proceedings of the KIEE Conference
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    • 2006.10b
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    • pp.154-158
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    • 2006
  • The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. Random Pulse Width Modulation (RPWM) is peformed by adding a random perturbation to switching instant while output-voltage regulation of converter is performed. RPWM method for reducing conducted EMI in single switch three phase discontinuous conduction mode boost converter is presented. The more white noise is injected, the more conducted EMI is reduced. But output-voltage is not sufficiently regulated. This is the reason why carrier frequency selection topology is proposed. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300v/1kW with $5%{\sim}30%$ white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with LISN, which are connected to the spectrum analyzer respectively.

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The Effect of VCB's Multiple Reignition Surge being Affected due to Circuit Parameters (진공차단기 다중재발호 써지에 미치는 회로 파라메터의 영향)

  • Kim, Jong-Gyeum;Jeong, Jong-Ho;Cho, Hyoun-Gil;Lee, Eun-Woong
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.15-17
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    • 1994
  • As VCB has many advantages which is an excellent interruption capability, compact structure, easy maintenance and light weight, it has been widely used as a load breaker. But steep-fronted surge voltage due to high frequency extinguishing capability in switching has been occurred. If it impinges into induction motor, it acts on the electrical stress, and causes to deteriorate winding insulation. In this research, in order to protect motor insulation from the steep-fronted reignition surge, the occurring condition, the cause of the reignition surge and the influence of circuit parameters which have been an effect on the occurrence of reignition and multiple reignition surge has been also analyzed.

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A Study on the Electromagnetic Transients at Switching Capacitor Banks in a Electric Distribution Electric Power Distribution Substation (배전변전소에서 캐패시터 뱅크 투입시 일어나는 전자과도 현상에 관한 연구)

  • 김경철
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.1
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    • pp.92-99
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    • 2002
  • Transient in an electric distribution system are mainly generated by switching. This paper presents analysis of switching surge and means of limiting the voltage magnification transient for high voltage power systems by using the EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor contraction capacitor banks to harmonics filters. An inductance in series with the capacitor bank was used to decrease the transient voltage at the customer bus to acceptable levels. And also simulation results used the EDSA harmonics analysis program show the effect of harmonics reduction.

A study on the Conducted Noise Reduction in Three-Phase Boost Converter using Random Pulse Width Modulation (Random PWM 기법을 이용한 3상 승압형 컨버터 전도노이즈 저감에 관한 연구)

  • Jung, Dong-Hyo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.51 no.3
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    • pp.120-125
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    • 2002
  • The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. In the switching-mode power converter, the output voltage is generally controlled by varying the duty ratio of main switch. When a converter operates in steady state, duty ratio of the converter is kept constant. So the power of switching noise is concentrated in specific frequencies. Generally, to reduce the EMI and improve the immunity of converter system, the switching frequency of converter needs to be properly modulated during a rectified line period instead of being kept constant. Random Pulse Width Modulation (RPWM) is performed by adding a random perturbation to switching instant while output-voltage regulation of converter is performed. RPWM method for reducing conducted EMI in single switch three phase discontinuous conduction mode boost converter is presented. The more white noise is injected, the more conducted EMI is reduced. But output-voltage is not sufficiently regulated. This is the reason why carrier frequency selection topology is proposed. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300V/1kW with 5%~30% white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with LISN, which are connected to the spectrum analyzer respectively.

Comparison of Active-Clamp and ZVT Techniques Applied to Tapped-Inductor DC-DC Converter with Low Voltage and Bigh Current

  • Abe, Seiya;Ninomiya, Tamotsu
    • Journal of Power Electronics
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    • v.2 no.3
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    • pp.199-205
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    • 2002
  • This paper compares three kinds of soft-switching circuits from viewpoints of surge suppression, load characteristic, and power efficiency for a tapped-inductor buck converter with low voltage and high current. As a result, these soft-switching techniques have achieved much higher efficiency of 80 % when compared with a hard-switching buck converter for the output condition of 1V and 20A.

Development of a Surge Protective Device for Signal Lines on Shipboard (선박 신호회로용 서지방호장치의 개발)

  • Seo, Hwang-Dong;Song, Jae-Yong;Han, Ju-Seop;Kim, Yoon-Sik;Kil, Gyung-Suk
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.1161-1165
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    • 2005
  • Due to the miniaturization of electrical components and assembles on signal circuits, transient overvoltages caused by switching operation or lightning surges have become more interesting concern to the field of electrical engineering. In this paper, the development of surge protective devices(SPDs) that can protect sensitive signal device on shipboard from overvoltages are described. Two kinds of SPDs are designed and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}s$ 2.1kA according to the IEC 61000-4-5 standard. From the simulation and experimental results, it is confirmed that the proposed SPDs have an enough protection performance with a low insertion loss and a low clamping voltage.

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