Voltage drop is always a problem for electrical
engineers. Every possibility is explored by electrical engineers to minimize
voltage drop to minimum level so to do effective utilization of generated
voltage and losses due to voltage drop.

We Know that Voltage= Current X Resistance

Now Resistance= Resistivity X length of conductor/ Area
of conductor

Now we get Voltage=

__Current X Resistivity X Length of conductor__
Area of conductor

Now we see that voltage has relation with length of conductor , current carried by conductor,
Area of conductor.

So by following means Voltage drop across a conductor can
be minimized :-

1.
Increasing the area of conductor

2.
Decreasing length of conductor

3.
Decreasing current across conductor

In additional to above there is fourth factor by which
voltage drop can be reduced i.e. by decreasing conductor temperature. Now that
factor comes from resistivity as resistivity decreases with decrease in
temperature. So there are four factors by which voltage drop across a conductor
can be minimized.

**1.**

__Increase the Area of conductor or by increasing Number of Conductors:-__
By using parallel conductors or by increasing area of
conductor resistance per unit length will be decreased, which ultimately leads
to decrease in voltage drop across conductor. With reduced voltage drop across
conductor will leads to increased efficiency across conductor. By using
parallel conductors will leads to lower the overall power losses which are
otherwise more in conductors of standard size

By limiting current across conductor voltage drop across
conductor get reduced proportionally. This can be achieved by reducing the load
connected to conductor. Usually capacitor bank is connected across the system
so to compensate reactive load current. This way current across conductor get
reduced which will leads to lower voltage drop across conductor.

But one should keep in mind that capacitor should not be
connected in oversize, otherwise it will leads to higher current across
conductor due to over compensation. Which will leads to higher voltage drop.

By reducing length of conductor during design stage voltage
drop can be minimized. It should be always practice to keep load near to panels
so that voltage drop can be minimized.

When conductor is heavily loaded then that will leads to
heating up the conductor, thus we can say that conductor temperature is dependent
on the factors listed above. As we know that conductor temperature is a
major factor in conductor resistance, and therefore in voltage drop.
The temperature coefficient of copper i.e., α, is 0.00323/°C, which
means resistance change of about 0.3% for each °C of temperature
change.

Temperature coefficient of resistance equation is as
below:-

R2 = R1 [1 + α · (T2 – T1)]

Where R1 is the resistance (Ω) at
temperature T1 and R2 is the resistance at
temperature T2.

Temperature T1 is often referenced at 75°C.
As noted, voltage drop is a particular concern at high conductor loadings,
where conductor temperatures will also be high.

**Table above shows the Maximum Recommended Lengths of Single-Phase Branch Circuits, as a Function of Load Current, Supply Voltage, and Conductor Size, for Both 3% and 1.5% Voltage Drops.**

**We can say that Voltage drop is necessary evil in electrical systems and great burden for electrical engineers.**

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