• Title/Summary/Keyword: line impedance measurement

Search Result 138, Processing Time 0.022 seconds

Design of Channel Impedance Measurement Equipment for Indoor Power Line Communications (옥내 전력선 통신 채널 임피던스 측정 장치 설계)

  • Heo, Yun-Seok
    • The Journal of Information Technology
    • /
    • v.8 no.3
    • /
    • pp.25-33
    • /
    • 2005
  • This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency 30khz$\sim$1Mhz band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

  • PDF

Impedance Measurement and Matching Technique for Medium-Voltage Powerline Communication (고압전력선 통신을 위한 임피던스 측정 및 정합 방안 연구)

  • 이재조;유정훈;홍충선;이대영
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.53 no.5
    • /
    • pp.345-352
    • /
    • 2004
  • Currently, high data rate PLC(Power Line Communications), up to 100 Mbps, which use frequency bandwidth between 2 MHz and 30 MHz is investigated very hard, and commercial PLC modem for low voltage powerline network (indoor) is coming soon into communication market. For the purpose of developing a fit communication system which has little distortion of signal and attenuation, it is surely necessary to know about channel environments of powerline. Especially, the impedance measurement of the powerline and impedance matching are very important. As is known, since medium-voltage powerline (22.9 ㎸) is still working, it is not so simple to measure the powerline impedance. In our study, a portable impedance measurement equipment is developed. It consists of coupling capacitor, a drain coil and impedance matching transformer. The equipment is easily connected to medium voltage line and impedance of power line is measured using a network analyzer. Also, measurement results are used for impedance matching of PLC signal. In fact, matching transformer with several different impedances are used. The matching transformer is connected between coupling capacitor and signal port. In this paper, the developed portable impedance measurement equipment and impedance measurement results are presented. Also impedance matching technique using matching transformers will be explained. We showed the result of the improved performance by the impedance matching.

A study of measurement of the unknown load impedance using sectioned transmission line (${\lambda}/4$ 전송선로를 이용한 부하단 임피던스 측정방법에 관한 연구)

  • Hwang, Soo-Sul;Hong, Sung-Yong
    • Journal of Satellite, Information and Communications
    • /
    • v.6 no.2
    • /
    • pp.91-96
    • /
    • 2011
  • In this paper, we present measurement method of the unknown load impedance. Load impedance is continuously varied by external environment conditions. This arbitrarily varied load impedance can be calculated using 3-point voltage measurement on ${\lambda}/4$ sectioned transmission line. We derived several numerical formulas from 3-point voltage measurement results and drew load impedance selection algorithm from calculated load impedance results. These numerical formulas and load impedance selection algorithm are verified by ADS simulation. Simulation results showed that arbitrary load impedance can be correctly measured using above mentioned formulas and selection algorithm.

New Techniques for Impedance Characteristics Measurement of Islanded Microgrid based on Stability Analysis

  • Hou, Lixiang;Zhuo, Fang;Shi, Hongtao
    • Journal of Power Electronics
    • /
    • v.16 no.3
    • /
    • pp.1163-1175
    • /
    • 2016
  • In recent years, microgrids have been the focus of considerable attention in distributed energy distribution. Microgrids contain a large number of power electronic devices that can potentially cause negative impedance instability. Harmonic impedance is an important tool to analyze stability and power quality of microgrids. Harmonic impedance can also be used in harmonic source localization. Precise measurement of microgrid impedance and analysis of system stability with impedances are essential to increase stability. In this study, we introduce a new square wave current injection method for impedance measurement and stability analysis. First, three stability criteria based on impedance parameters are presented. Then, we present a new impedance measurement method for microgrids based on square wave current injection. By injecting an unbalanced line-to-line current between two lines of the AC system, the method determines all impedance information in the traditional synchronous reference frame d-q model. Finally, the microgrid impedances of each part and the overall microgrid are calculated to verify the measurement results. In the experiments, a simulation model of a three-phase AC microgrid is developed using PSCAD, and the AC system harmonic impedance measuring device is developed.

Analysis on the Effects of the Induced Noise Voltage with the Impedance Changes of Telecommunication Line in the Power Inducting Situation (전력 유도 장애 발생 시 통신 선로의 접지체 임피던스 크기가 유도 잡음 전압에 미치는 영향 분석)

  • Choi, Mun-Hwan;Lee, Sang-Mu;Cho, Pyoung-Dong
    • 한국정보통신설비학회:학술대회논문집
    • /
    • 2007.08a
    • /
    • pp.227-230
    • /
    • 2007
  • In this paper, we have analyzed the change characteristics of induced noise due to the impedance change of the ground in both ends of telecommunication line. As what affects the induced noise, there are power influence or longitudinal transverse voltages and its weighted filtered voltage. In the result of measurement, we can see the noise level change due to the change of the ground impedance, that is, as the ground impedance at either end of the telecommunication line become grower, the noise level is increased, and as the ground impedance at either end of the telecommunication line become smaller, the noise level is decreased. However, we can't define the relation between ground impedance size and PIF in these measurement results, so we will have to carry out the measurement more deeply and more practically with various conditions in environmental viewpoint and/or experimental viewpoint to establish the definition between ground impedance size and PIF.

  • PDF

Analysis of Channel Noise and Impedance Characteristics for High-Speed Power-Line Communication (고속 전력선 통신을 위한 전력선채널 잡음 및 임피던스 특성 분석)

  • 김정훈;김선효;김상태;이영철;신철재
    • Proceedings of the IEEK Conference
    • /
    • 2001.06a
    • /
    • pp.37-40
    • /
    • 2001
  • Subject of this paper is analysis of channel noise and impedance characteristics for high speed power line communication to concerned noise of transmission line and impedance in the frequency range up to 30MHz. Parameters of transmission line was inducted from experimentally power line channel measurement. Moreover, Analysis of compared based on measurement of channel characters with simulation test for appear characters.

  • PDF

Measurement of Channel Impedance Characteristics for Indoor Power Line Communications (옥내 전력선 통신 채널 임피던스 특성 측정)

  • Heo Yoon-Seok;Kim Chul;Hong Bong-Hwa;Lee Dae-Young;Jun Kye-Suk
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.42 no.11
    • /
    • pp.79-86
    • /
    • 2005
  • This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency $30khz\~1Mhz$ band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

Measurement and Analysis of Line Impedance in Underground Cables (지중케이블 선로 임피던스 실측 및 분석)

  • Ha, C.W.;Kim, J.N.
    • Proceedings of the KIEE Conference
    • /
    • 2003.07a
    • /
    • pp.205-207
    • /
    • 2003
  • The line impedance is important data that is applied in all analysis fields of electric power system like power flow, fault current, stability and relay calculation etc. Usually, impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding wires, and earth resistance. Therefore, if there is a fault in cable system, these terms will severely be caused much error to calculation of impedance. Therefore, the line impedance were measured for this study in an actual power system of underground cables, and were analyzed by a generalized circuit analysis program EMTP for comparison with the measured value. These analysis result is considered to become foundation of impedance calculation for underground cable.

  • PDF

Precise Impedance Measurement of Coaxial Loads using Air Line Impedance Standards (Air Line 임피던스 표준을 이용한 동축형 부하의 임피던스 정밀 측정)

  • 강진섭;김정환
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.11 no.5
    • /
    • pp.788-795
    • /
    • 2000
  • In this paper, a method for the precise impedance measurement of coaxial loads using an offset open and short as the reflection standards and reference air lines with different lengths as the impedance standards is proposed. Measured input impedances of power sensors and thermistor mounts obtained from SWR bridges(5~400MHz) and a vector network analyzer(100~1,000MHz) are presented in the frequency range of 5MHz to 1,000 MHz.

  • PDF

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
    • /
    • 2005.07c
    • /
    • pp.2345-2347
    • /
    • 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.

  • PDF