10-04-2017, 09:34 PM
Transformer is the vital component in the electric power
transmission and distribution system. The problem of
overloads, voltage variation and heating effects is very
common. It takes lot of time to its repair and also involves
lot of expenditure. This work is all about protecting the
transformer under overload condition. Due to overload the
efficiency gets reduced and the secondary winding gets
overheated or it may be burnt. So, by reducing the extra
load, the transformer can be protected. This can be done by
operating another transformer in parallel with main
transformer through comparator and change over relay. The
comparator compares the load on the first transformer with a
reference value. When the load exceeds the reference value,
the second transformer will automatically be connected in
parallel with first transformer and share the extra load.
Therefore, two transformers work efficiently under overload
condition and the damage can be prevented.
For home appliances, commercial and industrial
loads, the transmitted voltage must be steeped down to a
distribution level. This may happen in several phases. In
sub-stations the voltage gets stepped down from
transmission level (in the tens or hundreds of thousands of
volts range) to the distribution level (typically less than
10,000 volts).
In this work, a slave transformer shares the load of
master transformer in the case of over load and over
temperature. A sensor circuit is designed to log the data
from master transformer and if it is found to be in overload
condition, immediately the slave transformer will be
connected in the parallel to the master transformer and the
load is shared.
Initially when we switched ON the load that load
will be shared by the first transformer. Once load has been
increased on first transformer above its rated capacity then
the stand by transformer (second) will share the load
automatically.
Here, we used regulated 12V, 500mA power supply,
7805 three terminal voltage regulator is used for voltage
regulation. Bridge type full wave rectifier is used to rectify
the AC output of secondary of 230/12V step-down
transformer.
