(一)
7 D7 c7 R R- q1 d% S+ zFirst, high-voltage transmission lines take advantage of the power equation, that is, power is equal to the voltage times current. Therefore, increasing the voltage allows one to decrease the current for the same amount of power. Second, since transport losses are a function of the square of the current flowing in the conductors, increasing the voltage to lower the cur-
rent drastically reduces transportation losses.
Plus, reducing the current allows one to use smaller conductor sizes
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注:
the square of: 平方
Plus:另外,再者
take advantage of 利用
高压输电线high-voltage transmission line
times
( u3 }9 L+ h! @3 E& h; v- q4 Z9 T表示“乘以”的是times,不是time 而且times是介词(原句中的动词是equal) 再如:Five times two equals ten. 五乘二得十。Power = Voltage × Current:power is equal to the voltage times current. - W+ f5 G0 m5 I# w
(二)
# V1 L* L2 A1 }6 r) R+ E* ^4 z/ hThe static wires in this case do not have insulators; instead, they are directly connected to the metal towers so that lightning
strikes are immediately grounded to earth. Hopefully, this shielding will keep the main power conductors from experiencing a direct lightning strike.
- y# ?% o) e1 B: \, _keep from...experiencing 防止····被
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(三)
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Power = Voltage × Current
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From the power equation above, raising the voltage means that the current can be reduced for the same amount of power. The purpose of step-up transformers at power plants, for example, is to increase the voltage to lower the current for power transport over long distances. Then at the receiving end of the transmission line, step-down transformers are used to reduce the voltage for easier distribution.
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从以上公式可以看出:From the power equation above,
降压器 step-down transformer
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For example, the amount of current needed to transport 100 MW of power at 230 kV is half the amount of current needed to transport 100 MW of power at 115 kV. In other words, doubling the voltage cuts the required current in half.
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使···减半 Cut in half
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(五)
The cost due to losses decreases dramatically when the current is lowered.
由···引起的 due to
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! \! U6 R! l/ M9 \6 _" i2 V6 kA conductor heats up when current flows through it due to its resistance. The resistance per mile is constant for a conductor.
heat up 温度升高,变热
constant
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adj
% p( K- g/ ^9 Z9 ]1) fixed and invariable; unchanging0 z d( S1 B" e+ m5 {( z7 P: Y
- }( I }0 D) `' f" ? s+ a$ \ v2) continual or continuous; incessant
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1 S* ~ L( A4 f, Y& h; l+ \; Bconstant interruptions, {3 h9 K9 d3 |* l Q- M
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3) resolute in mind, purpose, or affection; loyal1 O* l3 U- i6 F o' o
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(七)Steel is a poor conductor when compared to copper and aluminum; however, it is very strong. Steel strands are often used as the core in aluminum conductors to increase the tensile strength of the conductor.
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Steel is a poor conductor 导电性差(定语译成表语)
6 ^) C+ Z) r1 m6 H% Ctensile % \+ k- [4 m3 c# `* H& j# l
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adj
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/ a' q9 ]: I5 Z6 J# V9 B# ^# g* i1) of or relating to tension
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2) sufficiently ductile to be stretched or drawn out
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