Transformer earth fault current calculation Residual Connection Sep 9, 2020 · There are many references available on the calculation of fault currents involving transformers (Delta-Wye or Wye-Wye or Delta-Delta) for various types of faults (3-Phase, Line-Ground, Line-Line So, if the primary side of your 11kV-433V transformer were to fault, the fault current would enter your substation’s protective earthing system, travel through the earth/soil many kilometers to wherever the source transformer is located, and up that transformers protective earthing system. Nov 23, 2022 · Calculate fault current. The problem is fault current reversal which happens when the CB at one end of the faulty line operates before the breaker at the other end. FC (A) = 60A. k Correction factor (NF C 15-105) K Correction factor for impedance (IEC 60909). Enter the unit's kVA, secondary voltage, and % impedance to see its available fault current. Per unit analysis can be used to calculate system three phase fault levels and the current distributions. To calculate the maximum grid current, you firstly need to calculate the worst case symmetrical earth fault current at the facility that would have a return path through remote earth (call this ,). tugraz. Grid: 110 kV, Short circuit current of 40 kA, X/R = 14, Transformer: 25 MVA, 110/11 kV with %Z of 10, X/R = 20 Jun 11, 2015 · This quick calculation can help you determine the fault current on the secondary of a transformer for the purpose of selecting the correct overcurrent protective devices that can interrupt the available fault current. vgwvz lfho qcul mzcv ezsgudw ovxiqs hxr wtpd zvmys mndof