1.電気の種類による分類Classifications based on electric kinds
There is a classification based on an electric kind (alternating or direct current) in the one of the classification methods of the power transmission line.
Most power transmission lines are power transmission lines of the alternating current method.
2.交流の種類による分類Classifications based on kinds of alternating current
There is a classification based on a kind of alternating current in the one of the classification methods of the power transmission line.
Most power transmission lines are 3 phase alternating current methods.
There is extremely a few it, but the single-phase alternating current power transmission lines are built, too.
alternating current of the frequency of 50 or 60Hz are used for most power transmission lines.
3.回線数・電線配列による分類Classifications based on kinds of "the number of circuit and the conductor sequence"
In the one of the classification methods of the power transmission line, there is a classification to be based on a numerical difference of circuit to put on one support.
With 3 phase alternating current power transmission lines, one circuit consists of three conductors.
Therefore, we call the power transmission line "2 circuit power transmission lines" if six conductors are done an overhead wire of by a power transmission line steel tower.
And we call " 3 circuit power transmission lines", if 9 conductors are done an overhead wire of by a support.
And we call the power transmission line that three conductors are arranged horizontally "a horizontal sequence power transmission line".
In addition, we call the power transmission line that three conductors are arranged perpendicularly "a perpendicular sequence power transmission line".
In Japan, 2 circuit perpendicular conductor sequence power transmission line is facilities of the standard shape.
5.電線構造による分類Classifications based on conductor structure
One conductor is usually used for conductors of one phase.
We call the power transmission line which uses one conductor for one phase "single conductor power transmission lines".
However, with the power transmission line of the large-capacity high voltage, as for the conductor of one phase, there are many cases which plural conductors are used for.
We call the power transmission line which uses plural conductors (2,3,4,6 or 8) for one phase "bundled conductor power transmission lines".
1.送電電圧の違いによる規模の大小The change of the scale based on a difference of the power transmission line voltage
The overhead power transmission line uses air as an insulator.
Naked electric wires are put on the air as a power transmission line.
As we raise the power transmission line voltage, we must let conductor ground height increase and must enlarge the space of conductor aspect each other.
Therefore, naturally the supports height rises and opens at the interval of conductor aspect each other when the transmission voltage rises.
And the power transmission line of the high voltage becomes the large-scale facilities.
上記の「または」は、地域によって二つの内どちらか片方の電圧が採用されていることを示す。
国の制定した技術基準では、これら電圧はすべて「特別高圧」に分類されるが、架空送電線専門分野では170KV以上を「超高圧」と呼んでいる。
また、1000KV送電線のことを特に「超超高圧:UHV (Ultra High Voltage)」と呼んでいる。
なお、欧米では、公称電圧345KV~700KV送電線のことを、EHV(Extra High Voltage)と呼んでいる。
2.送電容量による規模の大小The change of the scale based on a difference of the transmission capacity
In the case of a power transmission line of the same voltage, we must set up big conducting wire to make transmission electricity big.
When we make a conductor big, we will use an extreme strong big member for a steel tower.
Therefore, with the power transmission line of the same voltage, scales of the structure are different with size of the transmission capacity (the thickness of the conductor).
As for the power transmission line that the voltage is low, a conductor to use is thin, and the transmission capacity is small, and the scale is generally small.
As the voltage of the power transmission line rises, the used conductor is big, and the transmission capacity tends to grow big drastically, and the scale is big drastically.
3.回線数による規模の大小The change of the scale based on a difference of the number of circuit
The power transmission line has basically most "2 circuit power transmission lines", and it is a standard form in Japan.
However, there is the thing that we put the conductor of plural routes on the same support from the viewpoint of "utilization of the land" and "construction costs reduction".
The power transmission line is seen a lot in the area where right of way security in the suburbs of the city is difficult.
We call it "4 circuit power transmission lines" if we grind two "2 circuit power transmission lines" together.
The facilities become large.
There are not many 6-8 circuit power transmission lines, but it is built in Japan.
最古の超高圧送電線 The oldest extra-voltage power transmission line
The Southern California Edison company in U.S.A. built the world's first voltage 220KV power transmission line to 386km between Big creek power station - Los Angeles in 1923.
220kVピッククリーク-ロサンゼルス線(アメリカ)
アメリカ、Southern California Edison会社が、電圧220KV、ピッククリーク発電所~ロサンゼルス間386Kmに建設し、1923年5月6日(大正12年)に運転開始した送電線(ピッククリーク線)が世界初(世界最古)の超高圧送電線である。
(詳細は当HP「世界初の超高圧(220KV)送電線誕生の物語」に掲載)
The world's longest span (the length 5,376m) was built by the power transmission line which crossed the Ameralik fjord of the Nuuk neighborhood in Greenland.
The power transmission line was built in voltage 132KV in 1993.
The 500KV power transmission line which crossed the Yangtze River in Jiangsu in China was built in 2004.
The steel tower built at the Yangtze River crossing recorded the highest length (346.5m) in the world.
最も長い送電線 (最長距離送電線) The longest power transmission line
The longest power transmission line was built in Brazil in the world and started use on november, 2013.
This power transmission line is the voltage of HVDC±600kV, and the length is 2,397km.
長距離送電線の限界は、技術的制約以上に経済的制約によるところが大きく、如何に安い電力単価(建設費および維持管理費合計の評価)で長距離送電できるか、が問われる。
この限界は、直流で約7,000Km、交流で約4,000Kmであろうとの検討がなされている。(CIGRE:1984Session,”PRESENT LIMITS OF VERY LONG DISTANCE TRANSMISSION SYSTEM” by L.Paris etc)
送電線(鉄塔)規模 The power transmission line of the biggest scale
In the world most the big power transmission line of the scale is West Gunma main line (1000KV design -500KV driving) in Japan.
本送電線の特徴は、ルートの殆ど全ての地域が人の全く住んでいないジャングル地帯であり、送電線設備に不具合・故障が生じた場合には調査、点検、復旧に多大な時間と労力を要することとなる。
したがって、立木の倒壊、山火事、その他強風による設備被害などを極力受けないよう送電線専用用地(Right of Way)の幅を約80mと広く確保するとともに樹木をほとんど全て伐採している。
また、万一設備被害が発生した場合には、その影響範囲を押さえ込むため「+極電線」と「-極電線」を別々の支持物に架線し、電線間隔を約40m離して同時に被害を受けることがないようにして、何れか片方の鉄塔が被害を受けても健全側の片極送電は可能なように配慮している。