Impedance Method Short Circuit Calculation

Impedances upstream and downstream a transformer are required to be transformed into their respective voltages using the following equations:

1. Primary Impedances
   Primary impedances when referred to the secondary of the transformer need to be transformed using the following equation:

   

   where:
   Primary impedances referred to secondary
   Transformer primary voltage
   Transformer secondary voltage

   Note: Above equation applies to resistance and reactances.

2. Secondary Impedances
   Secondary impedances when referred to the primary of the transformer need to be transformed using the following equation:

   

   where:
   Secondary impedances referred to primary
   Transformer primary voltage
   Transformer secondary voltage

   Note: Above equation applies to resistance and reactances.