2006-09-28 10:08:51 · 7 answers · asked by lito 1 in Science & Mathematics ➔ Engineering
The power lost in the transmission lines is equal to the current (I) squared times the resistance (R). Cut the current in half, and you cut the power lost by a factor of four. Cut the current by four, and the power lost is cut by a factor of sixteen. (P= Isquared x R). Follow the math?
How do you reduce the current transmitted without reducing the total amount of power transferred? Power transferred is the current times the voltage. You can transmit large amounts of power at a low current if you have a high voltage. (P = I x V)
You step down the voltage for residential use for safety reasons, and to increase the amount of current at the output end (more current provides more torque for electric motors).
Follow that?
2006-09-28 10:18:06 · answer #1 · answered by Randy G 7 · 1⤊ 0⤋
Electrical power is calculated by multiplying the voltage by the current. The resistance in a wire opposes the flow of current (amperes). Power consumed (as heat) in a conductor is the current (squared) multiplied by the resistance (ohms). To reduce power loss in a wire, reduce the current flowing through it. So if you need X-megawatts of power transferred, use the highest voltage available (which results in the least current). But high voltages are hazardous to consumers. So we use multi-kilovolts to transfer power long distances, then reduce it back to 220 volts for consumers.
2006-09-28 12:40:56 · answer #2 · answered by Scoop81 3 · 0⤊ 0⤋
Because of the power loss of transmitting over long distances.
From Wikipedia: Electrical power is invariably partially lost during transmission. This applies to short distances such as between components on a printed circuit board as well as to cross country high voltage lines. Loss power is proportional to the resistance of the wire and the square of the current.
Ploss = RI2
Because of this relationship, it is favourable to transmit energy with voltages as high as possible. This reduces the current and thus the power lost during transmission.
2006-09-28 10:18:27 · answer #3 · answered by Glenn N 5 · 0⤊ 0⤋
We step it up to carry it long distances because of the resistance in the wires. Resistance in wires causes voltage to drop. This doesn't matter when large amounts of volts are sent, but it would matter if low volts are sent.
2006-09-28 10:19:17 · answer #4 · answered by Anonymous · 0⤊ 0⤋
I often spend my half an hour to read this blog's posts daily along with a mug of coffee.
2016-08-23 07:46:26 · answer #5 · answered by ? 4 · 0⤊ 0⤋
Well, the first three hit it dead on. It's definitely because of I squared R losses.
2006-09-28 10:30:21 · answer #6 · answered by JKKIII 2 · 1⤊ 0⤋
Not sure how to answer this one
2016-08-08 16:03:32 · answer #7 · answered by ? 3 · 0⤊ 0⤋