Typical transformer X/R ratios 1

electrical429 · Sep 30, 2021

Is there a source of information that outlines typical transformer X/R ratios depending on MVA and voltage rating?

Also would be helpful to have the same information for underground cables.

RRaghunath · Sep 30, 2021

IEEE 141 the Red Book has curves indicating typical X/R ratios.

prc · Oct 2, 2021

For US market, the Red book gives X/R values. (Annexure 4A of IEEE 141-1993) But these values were taken from IEEE C 37.010 of 1979 -Application guide for HV circuit Breakers.C37.010 was revised in 1999. So, fig 17 of C37.010 will be more appropriate. For IEC areas, typical %Z values are given in IEC/TR 60909-2ed2.0-2008- Short circuit current calculation - Data of equipment for short circuit current calculation.

RRaghunath · Oct 2, 2021

Thanks prc for the insightful reply.
The current revision of IEEE C37.010 is dated 2016.
Not sure whether there is any further change in X/R value chart for transformers!

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Typical transformer X/R ratios 1

electrical429

Electrical

RRaghunath

Electrical

prc

Electrical

RRaghunath

Electrical

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