How can stepping up and down the voltage save energy in power transmission?

In summary, the problem involves estimating the power saved by stepping up the voltage from 120 V to 1200 V and then down again, rather than transmitting at 120 V directly. The power dissipated can be calculated using the formula I^2*R and comparing the potential drop over the load and transmission lines. By making diagrams and working back from the load, the current and voltage at different points can be determined.
  • #1
Angie K.
108
1

Homework Statement



If 39.4 kW of power is to be transmitted from a generating station over two 0.141-Ω lines, estimate how much power is saved if the voltage is stepped up from 120 V(rms) to 1200 V(rms) and then down again, rather than simply transmitting at 120 V. Assume the transformers are each 95 percent efficient.

Homework Equations



Power dissipated = I^2*R

The Attempt at a Solution


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Would I find the current using Ohm's Law, of the 120 V and then of 1200 V ? Using .142 as the resistance?

The compare it to the given power?

Then I'm not sure what to do or even if that is the right approach.
 
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  • #2
Angie K. said:
Would I find the current using Ohm's Law, of the 120 V and then of 1200 V ? Using .142 as the resistance?
No. The power loss depends on the potential drop over the transmission lines, which is not 120 V and 1200 V. You need to compare the potential drop over the load and compare it to that over the transmission.
 
  • #3
In both cases 39.4 kW of power (at 120V) has to arrive at the load. I would make two diagrams (yes I know they are simple) and then starting at the load, mark them up with Voltages and current as appropriate based on what you know and can calculate. Work back to the source.
 

FAQ: How can stepping up and down the voltage save energy in power transmission?

1. What is transmission energy loss?

Transmission energy loss refers to the amount of energy that is lost during the process of transmitting electricity from power plants to homes and businesses. This can occur due to a variety of factors, such as resistance in power lines or inefficient transformers.

2. How does transmission energy loss affect the environment?

The loss of energy during transmission leads to an increase in the amount of energy that needs to be produced by power plants. This can contribute to air pollution and greenhouse gas emissions, which can have negative impacts on the environment and human health.

3. What causes transmission energy loss?

There are several factors that can contribute to transmission energy loss, including the distance that the electricity needs to travel, the quality of the power lines and equipment used, and the efficiency of the power generation and distribution systems.

4. How can transmission energy loss be reduced?

There are several methods that can help reduce transmission energy loss, such as using higher quality power lines and equipment, implementing energy-efficient technologies, and improving the overall efficiency of power generation and distribution systems.

5. What are the consequences of high transmission energy loss?

High transmission energy loss can lead to higher energy costs for consumers, increased strain on power grids, and potential power outages. It can also have negative environmental impacts and contribute to climate change.

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