Effect of Spectrum Analyzer's Impulse Bandwidth on the Measurement of EM Waves Emitted from Partial Discharges in Multipath-Rich Environment

IEEJ Transactions on Electrical and Electronic Engineering (TEEE)


Locating Partial Discharge Source Occurring on Distribution Line by Using FDTD and TDOA Methods

IEEJ Transactions on Fundamentals and Materials


Estimation of the Number of Partial Discharge Sources Using Multichannel Blind Deconvolution of Electromagnetic Waves

We propose a method to estimate the number of partial discharge sources in multipath environment using the multichannel blind deconvolution method called the super-exponential deflation method. Blind deconvolution is a method of recovering transmitted signals from only observed signals without any a priori knowledge of the source signals. The deflation approach can extract a source signal which is non-Gaussian from the observed signals one by one. The deflation approach is repeated until all non-Gaussian signals are extracted, in which case the input signals become close to Gaussian noise. The eigenvalues of the spatial correlation matrix of the input signals indicate whether the input signals are Gaussian noise or not. Thus, the proposed method estimates the number of PD sources by repeating the deflation approach and analyzing the eigenvalues.


Development of Recursive Interpolated D/FFT for On-line and Highly Accurate Frequency Analysis


電磁調理器からの中間周波漏れ磁界による体内誘導電流の解析と平均化処理

電磁調理器からの中間周波漏れ磁界による体内誘導電流の解析と平均化処理

The Journal of the Institute of Electrical Installation Engineers of Japan


Time-Frequency Visualization of Vibration Phenomena generated on Turbine Model using Wavelet Transform

タービンモデルにおける振動現象のウェーブレット変換による時間周波数可視化

In this paper we presented results of fundamental study to introduce the wavelet transform to vibration diagnosis for a turbine. It is required to detect typical vibration of the turbine accurately. The wavelet transform is used in many fields because it is able to visualize a phenomenon in a time-frequency domain. Modern power plants usually use one-high pressure and one or two lower pressure turbines. We made a turbine model with 3 rotors supported with journal bearings to simulate contact vibration, oil whip, and clearance vibration. The vibration phenomena were measured with vertical and horizontal displacement meters at the rotors, and with vertical and horizontal accelerometers at the bearings. The vibration phenomena were visualized in the time-frequency domain by the wavelet transform. This paper especially shows the results of the acceleration signals. It is found that the dynamic spectra obtained by the wavelet transform of the acceleration signals are different for each vibration. Therefore, this method is able to distinguish the vibration phenomena. And furthermore, the contact point is localized by the proposed method.

電気学会論文誌B (電力・エネルギー部門誌)


Analysis of induced current density inside human model which stands on conductive ground layer in uniform electric field

The introduction of extremely low frequency electric fields with human body has become an increasingly important subject since potential health hazards due to the electric fields emitted by extremely high-voltage power lines. The health effect of the weak current induced in the human body as a result of the interaction between human body and power frequency electric fields has been investigated. In this paper, the finite element method is applied to the analysis of the current density distributions in the human model which stands with erect position on the conductive ground layer in the uniform electric field, and the characteristics of such internal current density distributions are clarified.


表面電荷法と有限要素法による非接地人体モデル内の誘導電流密度解析

表面電荷法と有限要素法による非接地人体モデル内の誘導電流密度解析

The Authors have developed a method for the analysis of the induced current density in the three-dimensional shape model by a two-step process consisting of: (1) the derivation of the induced current flowing in from the surface of the human model by the surface charge method; and (2) the application of these values as the boundary values of the finite-element method using an isoparametric hexahedral element.

電気学会論文誌B (電力・エネルギー部門誌)


スイッチング変調技術による三相零相出力成分の生成と活線絶縁診断システムへの適用

スイッチング変調技術による三相零相出力成分の生成と活線絶縁診断システムへの適用

This paper deals with a power supply using switching modulation technique, and its application to the hot-line insulation diagnosis. One of the distinct features of the switching modulation techinque employed in this study is that the zero-phase-sequence voltage with arbitary frequency is generated easily in the three-phase power system. Basic composition is just to add a switching modulation device to the commercial power supply or charged indoor main line. Therefore, it is not necessary to feed a signal current from the signal power supply to the grounding conductor via a pouring transformer as required by current hot-line insulation diagnosis system. When a power supply using switching modulation technique is used to hot-line insulation diagnosis, it is not necessary to modify or change existing commercial power facility. Therefore, there is a possibility that this may advantageously be used as a power supply for mobile type diagnosis. This paper deals with basic theory of switching modulation technique, and the phase rotation characteristics which play a basic role in three-phase power supply, and summarizes basic composition and performances of a trial manufactured experimental device. Furthermore, results of discussion are introduced concerning the conditions and method of its apllication to indoor wiring of fatories and buildings.

電気学会論文誌B (電力・エネルギー部門誌)


屋内配線の活線絶縁診断装置の開発(第2報)

屋内配線の活線絶縁診断装置の開発(第2報)

In order to test the hot-line insulation of low-voltage house wiring, we usually measure the earth leakage current with a clamp-type current transformer (CT) through which a bunch of main line (two wire line) is placed at the service entrance. In this method, however, the measured value includes not only the effective component to be measured, but also the inductive components of the current due to the capacitance of house wiring to the earth and the load current. Generally, the effective component is small compared to the sum of the inductive component. Therefore, in order to obtain correct measured values, it is essential to develop a technique to remove these inductive components.In order to remove the inductive component due to the load current, we have developed a bypass function element (hereinafter called as breaker attachment) that is applied to a circuit braker equipped at service entrance or branch points. As for the removal of the capasitive current to the earth, the DFT method has been introduced to the measurement using the so-called hyperbolic function method that was developed before. This hot-line insulation measurenent equipment is capabable of measuring the insulation measurement of 10 MΩ within the error of less than ± 5% under the conditions of load current of 10A and capacitance to the earth of 0.08 μF.

電気学会論文誌B (電力・エネルギー部門誌)


屋内配線の活線絶縁診断装置の開発

屋内配線の活線絶縁診断装置の開発

電気学会論文誌B (電力・エネルギー部門誌)


超高圧送電線下の楕円体状人体モデル内部の誘導電流密度解析

超高圧送電線下の楕円体状人体モデル内部の誘導電流密度解析


Analysis of induced current density in grounded and ungrounded prolate spheroid models in concurrent ELF electric and magnetic fields


電界中の絶縁性円板上に直立する人体モデル内電流密度分布

電界中の絶縁性円板上に直立する人体モデル内電流密度分布

The Transactions of The Institute of Electrical Engineers of Japan


組織膜を考慮した生体モデル内における磁気的低周波誘導電流特性

組織膜を考慮した生体モデル内における磁気的低周波誘導電流特性


Analysis of Induced Current Density in Grounded and Ungrounded Prolate Spheroid Models in Coucurrent ELF Electric and Magnetic Fields

極低周波電磁界内の接地および非接地の回転楕円体状生体モデル内部の誘導電流密度解析


Quantification of coupling between two-dimensional low-frequency magnetic fields and a sperical model of biological substance

Electronics and Communications in Japan (Part II: Electronics)


互いに平行および直交する低周波電界·磁界内の球状導体モデル内部の誘導電流密度解析


電界中の非接地人体モデル内に誘導される電流密度分布

電界中の非接地人体モデル内に誘導される電流密度分布


電力周波数の電界により人体モデル頭部脳内に誘導される電流密度分布

電力周波数の電界により人体モデル頭部脳内に誘導される電流密度分布


ELF磁界による2媒質偏心球生体モデル内の誘導電界分布特性の解析

ELF磁界による2媒質偏心球生体モデル内の誘導電界分布特性の解析


2次元低周波磁界と球状生体モデルのカップリング現象の定量化

2次元低周波磁界と球状生体モデルのカップリング現象の定量化

The Transactions of the Institute of Electronics, Information and Communication Engineers B

電子情報通信学会論文誌(B)


Study on magnetically induced current densities in spherical model of biological object under power lines

Bulletin of Faculty of Engineering, The University of Tokushima


磁界密度の不平等性が単媒質生体モデル内の誘導電界に及ぼす影響

磁界密度の不平等性が単媒質生体モデル内の誘導電界に及ぼす影響


電界中に置かれた導電率の異なる内部および外部組織からなる円柱モデル内の電流分布

電界中に置かれた導電率の異なる内部および外部組織からなる円柱モデル内の電流分布


位相差を有する低周波水平·垂直磁界内の球状人体モデル内部の誘導電流密度解析

位相差を有する低周波水平·垂直磁界内の球状人体モデル内部の誘導電流密度解析


インピーダンス法による低周波磁界中に置かれた生体モデル内の誘導電界解析手法

インピーダンス法による低周波磁界中に置かれた生体モデル内の誘導電界解析手法


Induced current characteristics of square probe placed level in a parallel DC and AC lines-to -plate electrode system

Proceedings of the Institute of Electrost


表面電荷法と有限要素法の2段階手法による人体モデル内誘導電流密度の解析

表面電荷法と有限要素法の2段階手法による人体モデル内誘導電流密度の解析

電子情報通信学会英文論文誌(B)


Numerical method of the ion flow field calculation using the up-wind approximation


Measurements of power frequency electromagnetic environments and consideration into exposure evaluation


交流電界中の人体モデルに誘導される電流密度の解析

交流電界中の人体モデルに誘導される電流密度の解析

電子情報通信学会論文誌(B)


商用周波数平等磁界中に置かれた金属平板周辺の磁束密度分布ー平板の寸法及び透磁率の影響

The Journal of the Institute of Electrical Installation Engineers of Japan


商用周波数平等磁界中に置かれた非磁性金属平板周辺の磁束密度分布の実験的検討

商用周波数平等磁界中に置かれた非磁性金属平板周辺の磁束密度分布の実験的検討


Total magnetic flux density meter developed for power frequency magnetic field characterization


Analysis of 60-Hz magnetic fields near ground level in 187-kV switchyard of a 187/66-kV AC substation


固体電位記憶素子を用いた携帯用ELFドシメータの開発

固体電位記憶素子を用いた携帯用ELFドシメータの開発


簡易磁界計算法を用いた電力用変電所構内におけるELF磁界分布推定法の検討

簡易磁界計算法を用いた電力用変電所構内におけるELF磁界分布推定法の検討


Development of real-time system for simultaneous observation of visual discharges and leakage current on contaminated dc indulators

IEEE Transactions on Electrical Insulation


A three-dimensional method for calculating currents induced in bodies by extremely low-frequency electric fields


電力周波数電界内に置かれた導電率が異なる二種類の組織を有する人体内部の電流分布

電力周波数電界内に置かれた導電率が異なる二種類の組織を有する人体内部の電流分布

The Transactions of The Institute of Electrical Engineers of Japan


Analysis of magnetic field profiles in electric blanket users


電気カーペットからの電力周波数磁界の解析

電気カーペットからの電力周波数磁界の解析


ELF electromagnetic environment in power substations


電力変電所構内の地表面近傍における磁界計算法

電力変電所構内の地表面近傍における磁界計算法


Power generator control by variable structure theory


ホットスポットによる絶縁破壊電圧の低下特性

ホットスポットによる絶縁破壊電圧の低下特性


複数の残存素線をもつビニルコードの溶断着火特性

複数の残存素線をもつビニルコードの溶断着火特性


Application of finite element method to analysis of induced current densities inside human model exposed to 60-Hz electric field

IEEE Transactions on Power Apparatus and Systems


交流送電線下の人体モデルに誘起される電界強度

交流送電線下の人体モデルに誘起される電界強度


A method of suppressing fault currents and improving the ground level electric field in a novel six-phase power transmission system


素線切れモデルビニルコードの着火電流範囲

素線切れモデルビニルコードの着火電流範囲


交流電界中の人体内に誘起される電界の解析ー有限要素法の適用

交流電界中の人体内に誘起される電界の解析ー有限要素法の適用


送電線用しゃへい線への電圧印加法

送電線用しゃへい線への電圧印加法


インパルス電流思畳による直流アークの消孤と再点孤

インパルス電流思畳による直流アークの消孤と再点孤


送電線下地表面近傍の電界分布の比較方法

送電線下地表面近傍の電界分布の比較方法


電力線と静電遮へい線との並列送電における直列コンデンサ補償の影響

電力線と静電遮へい線との並列送電における直列コンデンサ補償の影響


絶縁用ゴム手袋の貫通破壊に及ぼす開閉サージの影響

絶縁用ゴム手袋の貫通破壊に及ぼす開閉サージの影響


絶縁被服電線の劣化履歴と火災危険について

絶縁被服電線の劣化履歴と火災危険について


配電用エポキシ樹脂がいしの屋外曝露試験

配電用エポキシ樹脂がいしの屋外曝露試験


Development of leakage current monitor for indoor pollution study


Influence of dry band on flashover characteristics of polluted insulators

Bulletin of Faculty of Engineering, The University of Tokushima


がいし汚損面の吸湿現象に影響を及ぼす要因の解析

がいし汚損面の吸湿現象に影響を及ぼす要因の解析


汚損条件下における電力供給システムの絶縁信頼度

汚損条件下における電力供給システムの絶縁信頼度


汚損がいしのフラッシオーバ確率

汚損がいしのフラッシオーバ確率


がいし汚損面の吸湿密度，濡れ電流およびフラッシオーバ電圧の吸湿依存性

がいし汚損面の吸湿密度，濡れ電流およびフラッシオーバ電圧の吸湿依存性


衝撃電流による金属線の溶融爆発現象について

衝撃電流による金属線の溶融爆発現象について


汚損フラッシオーバ現象に対するがいし表面温度の影響

汚損フラッシオーバ現象に対するがいし表面温度の影響


モデルによる汚損面の吸湿，濡れ電流およびフラッシオーバ特性の解析

モデルによる汚損面の吸湿，濡れ電流およびフラッシオーバ特性の解析


Visualization of Electromagnetic Waves Emitted from Partial Discharge using the Constrained Interpolation Profile (CIP) Method

IEEJ Transactions on Electrical and Electronic Engineering (TEEE)