Abstract
At the end of 1927, the Nihon Electric Power Company has completed the erection of its Tokyo Transmission Line, deemed to transmit the power developed at River Kurobe, toward Tokyo and. Yokohama. This line is of 154, 000 volts and 301.3 kilometres in length, one of the longest lines of the same class. The author, together with a few comrades, went to Yanagawara Power Station for the inspection and tests of the same line as well as the station. After routine tests having been finished, the following special tests were carried out:-
(1) Charging of each line against the earth.
(2) Measurement of the induced voltage in a neighbouring public telephone line, and also in the company's communication line.
(3) Measurements of line-to-earth impedances and admittances, line-to-line impedances and admittances.
(4) Charging various lengths of the line at three-phase normal tension.
As comparing the test results with those obtained by calculation bassd on the well-known theories and formulae, it is generally acceptable that the lineto-earth reactance of one conductor is approximately 0.75 ohm per kilometre at 60 cycle in spite of the diameter and clearance of the conductor, and that otherwise the test results meet fairly well with the calculation.
Making use of the observed data as much as possible, the author then tried the calculation to find the grounding current in case of one-line fault on any part of the line, for five different systems of neutral grounding. (i. e:-600ω-∞, 600ω-600ω, 0-0, ∞-0, 0-∞: here the figures represent the ohmage of the grounding resistors at generating station and at substation respectively.) Comparing these cases, he may conclude that the double dead-grounding (0-0) is most favourable for this line, taking both the inductive interference and protective-relay operation into consideration. However the "stability" of the transmission as affected by these modes of grounding is here entirely out of the question.
The conten's of this paper are as follows:-
1. A brief description of the Tokyo Transmission System.
2. Kinds of tests made.
3. Pressure test.
4. Measurements of induced voltage in communication lines.
5. Determination of various line constants.
6. Line charging test.
7. Maximum power transmitted by this line.
8. Calculation of grounding currents in case of one line fault.
