In the high voltage transmission line whose neutral point is grounded, if there occur an accidental ground on one of the conductors, a heavy short circuit current will flow through the earth, inducing a voltage in the neighbouring communication lines by the electromagnetic action. In some cases, the voltage thus induced in the communication lines may reach to such a dangerous amount as to destroy the apparatus connected to the communication lines or to effect a heavy accoustic shock to the telephone operators. In Japan, especially, the geographical circumstances does not permit to leave a sufficient distance between both the power and the communication lines.
The investigation and field surveys have been continued for more than ten years by many electrical engineers under the auspices of the Engineer in Chief, Bureau of Electricity, Ministry of Communications, together with those of the various power companies, whenever the main transmission lines have been completed ; the results thus obtained will be described in this paper, having the contents as follows,
(1) The reasons why this problem must be considered as an important one in our country,
(2) The formulae for the calculation of the electromagnetic incuced voltage in the communication line are stated, quoting the Dr. Shibusawa's⁽¹⁾ formulae and the formula proposed by the Verband⁽²⁾ Deutcher Elektrotochnikers,
(3) The method of actual measurement of the electromagnetic induction and the result are shown,
(4) In our test results, these are several points of which we must take care, for examples, the relations between the magnitude of the electromagnetic induced voltage and that of the inducing current through the earth, or the frequency of the inducing current,
(5) Comparison of the actual results with the calculated ones,
(6) Conditions of proximity between both the power and the communication lines in our country are described,
(7) The magnitude of the electromagnetic induction is seemed to depend on the geological circumstances and the localities where the power and the communication lines pass,
(8) Considering the relations shown in (7). and from our test results the author proposes a new formula for a time being which would become to be modified in the future by the further experiments,
V=KfI∑l₁/b₁
where V=the induced voltage in the communication line, in volts,
f=the frequency of the current through the earth or the inducing current,
l₁=the length of a portion of the power line, in meters,
b₁=the distance between both the lines, in meters, when they are parallel. If they are not parallel, the arithmetic mean of the extreme two distances perpendicular to the power line, as shown in Fig. 13,
K=a constant depending on the geological conditions of the district where both the power and the communication lines pass, and it will be approximately as follows in our country,
i. Mountain district K=(0.5 to 0.8)×10^-3
ii. Plain district K=(0.25 to 0.4)×10^-3
but the magnitude of the induced voltage is seemed to be different according to the localities where the lines pass, in the numerical values of K shown above, 0.5 and 0.25 are the values in the mountain and the plain districts respectively in one locality, while the values 0.8 and 0.4 are those in another locality,
I=the short circuit current through the earth of the power line, in amperes,
(9) In Japan, we have not met with difficulties of the electromagnetic disturbances on the communication lines due to the power lines.
(This paper has the same contents as those in the "Report on the Electromagnetic Disturbance on the Communication Line due to an Accidental Ground of the Power Line" by S. Mayebare and E. Fukawo, presented to the Fourth Session of the International Congress of Extra High Tension Network, which will be held in Paris this year)

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本篇は最近市場に現はれたジヨンソン、ウツド及デユフールの三種の陰極線オツシログラフの得失を前二者に對する筆者經驗に基き比較對照したものてある。是等のオツシログラフの中電氣感度高きものは寫眞感度低く、これに反し寫眞感度高きものは電氣感度低く何れも一長一短未だ以て理想的と言ふ事は出來ぬ。是等の兩感度を同時に良好ならしむるは陰極線の本質上頗る難事ではあるが、現在の陰極線オツシログラフは此要求を充す事餘りに不充分にて夫々非常に限られたる用途にしか使用する事が出來ない。
猶ウツド型陰極線オツシログラフによつて得られた寫眞の異常現象に就いて一言してある。

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變壓器が今日の商取引に於て注文せらるゝ場合に、仕樣書によりて與へらるゝ所の條件の下に於て設計せらるゝ場合に於ては、最小價格變壓器を定むべき範圍は極めて小範圍に局限せらるゝ者なる事を述べてある。

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普通型三相鉛被ケーブルの全誘電體損失を測定するには、使用状態即三相電壓を加へて測定するのが一番良いのである。もし簡單のために單相電壓により心線鉛被間及心線相互間で測定して、其等の和をとつた場合には、如何なる程度の差があるかは、實驗に待たねばならない。此の報告には電力計法を用ひ、数種のケーブルを種々の電壓の下に於て、此の兩方法によつて測定せる結果が比較されてある。

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直流發電機は其磁路の残留磁氣のため定まれる極性を有するは今更申す迄もなし。廻轉變流機は交流自己起動に於いて、其磁路の殘留磁氣は廻轉磁界の交番磁化によつて壞滅せらるるを一般とするを以て、同期後生ずる直流電壓の極性は不定なり。筆者は其磁路に保〓力強き磁氣質を使用し、交流自己起動に際し磁路は其殘留磁氣を殘存し恰も極めて弱き勵磁の如くはたらき、或る條件の下に於ては直流電壓が常に正しき極性を呈する如く同期する變流機を考案し、依て變流機も亦直流發電機と同樣に成極せしめ得ることにつき研究を加へり。

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同期電動機の亂調が其電動機に及ぼす電磁的影響を實驗的に調べだ。其結果亂調は流入電流の増加と力率の降下とを招き、且の亂調を機械的に測りし値と電流増加程度との間には磁化曲線と似た曲線に示さるる關係あるを知つた。筆者は此現象は、亂調により勵磁の實効値が減ずる爲であると論じ、其爲に數種の實驗を擧げた。其他亂調に関する諸現象を測定して、其説明を試みた。

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歐洲及米國に於ける三萬ヴオルト以上の超高壓地中電纜に關する概況を述べH型及普通型地中電纜の比較に及び架空線條に關しては超高壓架空送電線路に於ける硬銅撚線鋼心アムミニユーム撚線及中空線使用の實況を略述したのである。

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