Surge Protection 1

[snorks]

Hi,
I'm doing a system computation for surge protection sizing and I have a question about the E and I values when the surge is moving through a step transformer. The surge voltage will pass through the transformer until its windings are destroyed.

I know the BIL of the transformer, but will the surge voltage and current be altered by the ratio of the transformer windings?

Thanks

 

[davidbeach]

To the extent that the surge is inductively coupled through the transformer, it will be affected by the ratio. To the extent that the surge is capacitively coupled through the transformer, the ratio will be irrelevant. You need a detailed LRC model of the transformer that is good over a wide range of frequencies to get good results.