# what are the advantages of transmitting electric power at high voltage levels?

Relevance

Think of voltage as the "Push" of the electricity, the higher the better for long distances.

• 4 years ago

When you step up the voltage in long distance transmission, you reduce the current for the same power. So you can transmit more power with the same size wire. And in distribution it is necessary to drop the voltage so AC is the way to go. AC can be transformed because the fluctuation of the voltage allows for transforming. In the transformer a magnetic field is induced into the core and then this field is tapped by a different number of coils in order to increase or decrease the voltage. Since DC does not reverse itself, the magnetic field stays constant and there is no fluctuation of the field. Current is induced in a conductor by the conductor moving within a magnetic field or the field moving with respect to the conductor. This does not happen with DC.

• Anonymous

The power loss in the high transmission grid is the resistance of the grid wires times the square of the current through them.This means if you multiplty the grid voltage by 2 then the grid current is halved and the power loss is reduced by the factor (1/2)squared =1/4 of the original.If you change the transmission voltage from 1000v to 100,000 volts the power loss will fall by the factor 1/100 x 1/100 = 1/10,000.If this wasn't done people living under power grid lines would be able to sit in their gardens ,and make toast by pointing a slice of bread at the overhead lines.

Say ur gen is supplying 250V at 100MW to cables.The current will be substantial and the power loss in the transcable=I^2*R as miles of copper/aluminium cable have large resistance. If you step up the voltage using a transformer to say 425kV, you step the current down in the inverse ratio.ie by 1/1700..so the power/energy loss in the cable is now (1700)^2 times less, by a factor of about 3million! ..just remember to step the voltage back down at the consumer end.otherwise customers will get a bigger shock than their electricity bill!

Oh aye! well dun Paul my man..the wires can be made much thinner as they need to carry less current saving on money and materials..PS why am I still paying Scottish Power £1000 pa after all these economies??

• Paul F
Lv 6

Not only the savings because the cross-sectional area of the conductors and therefore the weight of copper can be made significantly smaller, but it allows the distance between towers to be increased, having to support much less weight. So less towers are needed.

There are always pros and cons, the insulators have to be much larger and costly. In addition step-down transformers have to be added down the line.

Lower line losses and lower cost of equipment. An example is that a 4/0 wire will carry maybe 200 amps. At 120v that will power a house. At 69KV it will power 100 homes.

• Anonymous

It reduces transmission losses.

If the dissipation is I^2 x R, then lowering the current (by increasing the voltage) means less heat waste. It also saves on expensive copper conductors.

Less I squared r loss

Lower amperage higher voltage

say a fixed fixed load =2mw @.8 power factor

at 400VAC it will draw 3612 amps

at 11 KV AC it will draw 131 amps

now imagine the cable you need to supply the load, and the further away it is the bigger the cable will need to be to avoid volts drop