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View Full Version : Three-phase transformers formulas.


clsmooth
Nov 8, 2009, 07:20 PM
I have two three phase rnasformers connected by a transmission line. I know transmission-line impedance is j100 ohms, and the load impedance is 4+j1 ohms. I need to find the generator current, the transmission-line current, the load current, the load voltage, and the power delivered to the load.

I do not know the formulas I need to use to calculate each of the previously stated currents and power.

KISS
Nov 9, 2009, 06:46 PM
Been a while, but I think you can assume that:

1. transmission line Z is a lumped Z
2. Generator output is Vs @ 0 deg is going to be a complex voltage source

You have a series circuit consisting of 100J and 1J

I think you do Kirkcoff's law assuming a complex voltage source.
and a complex current.

e.g. Vs @ x deg = (4+101j)*I at y deg

Since Vs is the reference, assume 0.

Power is V*I * cos theta

It's been a while. Like 35 yrs.

SO, find V @ 0 deg and find I t theta deg and do the math with the parts.

Homework, I'm sure.