Why transmission line has high
voltage?
Why electricity transmit at high voltages to us from grid station.
This is the most important and knowledgeable
question, but many people do not consider it, and many people wonder why the transmission
line transmit at high voltage, so now we will talk about this question.
transmission line |
Basically you know that one transmission line will carry a lot of load, because the whole city or more load is on "one line", so one transmission line carries a lot of load.
So if high load will run then high amount of
current will flow by a wire, as the current will flow several kilo amperes, so
the wire, from which the current will flow should be thick wire so that it can support
the current.
And if thick wires use in transmission line then
we need to many supporter tower for give support to wire, and will required to
high maintenance, so if thick wire used and many supporter tower, and its
maintenances, these things will be high costly and will impossible to maintain
heavy wire.
So we needs to reduce the flowing current, that
thin wire can support easily, and reducing current only possible by high
voltages.
This is the law of Electrical system that when
voltage will increase then current will decrease, and when voltage will
decrease current will increase. This is law, which everywhere can work such as both current "AC" or "DC".
Now understand this law by calculation.
Example:- We have a fan which has 50 watt power,
so this fan will run at 220v then it current will take 0.22 ampere.
Calculation:-
Fan Power = 50watt
Supplied voltage = 220
Current = ??
Power / Voltage = current
50/220= 0.22
Means this fan if run at 220v volt, it will take 0.22 ampere but this same fan if run at 12v then
its current will increase.
Like this:-
Same formula
Fan Power = 50watt
Supplied voltage = 12
Current = ??
50/12= 4.16 ampere
Now this same fan will consume 4.16 ampere current.
This remember that any appliances or equipment
has different fixed Power.
Such as power can be different of different
equipment, but it not can be change.
Example:- If a refrigerator's power is 500 watts its power will always remain
same, but if it run at different voltage then its current will be change.
In Easy words that voltages is effected on
current not on watt.
For this, we use high voltage in the
transmission line for transmit electricity, such as much voltages will increase
current automatically will decrease, this reason that transmission line has high
voltage that wire size can be reduce.
Benefits of high voltage in transmission:-
- Current can be reduced
- Wire size can be reduced
- Needs of only some Supporter tower
for wire supporting - Low maintenance
- No voltages loss
- Best efficiency
- Easy to transmit
- Low cost.
This is possible that much voltage we will increase
current will decrease, and wire size will reduce. But it is not case, as much
as we want to increase the voltage, we can increase, because much more voltage
increased, then this will make dangerous, and made difficult to handle and
maintain, for this we used only 11kv 33kv 66kv 132kv in transmission line.
Why high voltage will dangerous and
difficult to maintain?
When the electricity or current flowing through a wire or conductor then magnetic field will make around it, this magnetic field depending at voltages, if voltage is low then magnetic field will generate in low amount, and if voltage is high then magnetic field also will generate in high amount, and this magnetic field also will spread out side around wire, again it much spread its depends on voltage.
So if voltage is very high then its magnetic filed will more spread, which is dangerous, for this we will needs to use tall supporter tower, so if we use tallest tower then its cost will high.
And if voltage will very high then need to high rating of insulators, which used for wire holding at supporter tower.
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