advantages of power transformers
Blaz gave a logical and correct answer and I am pretty sure that is the answer you were looking for. But the real advantage of a power transformer over a regular transformer is it`s ability to handle large quantities of volt amps. A regular transformer can step up or step down an AC voltage just like a power transformer can but it can not handle the volt amps required of a cross country electrical power delivery system.
it is used to step-up or step-down the voltage when used to transfer electrical energy over long distances. to put it in simple terms - the voltage is stepped up from the power generation plant so that there is a minimal loss of electrical energy when it is being transferred through wires. and it is stepped down when it reaches the destination for usage.
1, less susceptible to parasitic thermocouples and pressure drop along the wire resistance and temperature drift of the transmission line can be very inexpensive twisted pair wire finer; 2, in the current source output resistance is large enough, the magnetic field sensor coupled to the wire the voltage loop will not have a significant impact, because the interference caused by the current is very small, usually using twisted pair can reduce the interference resistance; 3, the capacitive resistance of the receiver causes interference on the error, both for 4 ~ 20mA wire loop, the receiver resistance is usually 250 (sample Uout 1 ~ 5V) that resistance small enough to produce significant errors, therefore, can allow the cable length longer than the voltage telemetry system further; 4, each single display device or recording device can be read in the wire lengths between the different channels for access, not caused by wire length ranging between accuracy; 5, 4mA to zero level, to determine the open circuit or sensor is damaged (0mA state) is very convenient. 6, in the easy addition of two-line outlet surge and lightning protection devices, is conducive to safe mine explosion.
Another advantage can be, depending on the application, isolation between primary and secondary circuits.
