How Does Imbalance in Transformer Secondary Affect Primary


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An imbalanced load on a transformer secondary in star arrangement with star point earthed, if there is an imbalance in the secondary phase currents due to load, how will this show up in the delta primary currents at 11kV? What are the equations/rules of thumb? We know a 'worst case' imbalance in the secondary and want to set imbalance protection on the 11kV feeder to the primary. I can't find any info on how this is calculated. It is a 2MVA transformer.

Any help much appreciated.
Now you really need a electrical specialist to address the analytical details, but once you start getting phase imbalances in the secondary, you also see phase current imbalances in the primary.

You don't want large imbalances. They can arise if you lose a winding on a motor (single phasing a motor), or various leakage currents to ground.

In the transformer core, the imbalanced phase currents affect the degree of saturation in different areas of the core and the transformer losses.
Imbalance can show up on the primary side of the transformer. The magnitudes of the imbalance depends on the connection type (star/star, delta/star) and cause of the imbalance.