How do you calculate the unsymmetrical fault current in a circuit?

Line-to-Ground (L-G) fault: Occurs when one conductor (line) of a three-phase system comes in contact with the ground or an object at ground potential.

Line-to-Line (L-L) fault: Occurs when two conductors (lines) of a three-phase system come in contact with each other.

Double Line-to-Ground (LL-G) fault: Occurs when two conductors (lines) of a three-phase system come in contact with each other and the combination comes in contact with the ground.

To calculate the unsymmetrical fault current, you typically follow these steps:

Fault Analysis: Determine the type of fault (L-G, L-L, or LL-G) that has occurred in the circuit.

Pre-Fault Conditions: Collect necessary information about the circuit, such as the pre-fault voltage, impedance of different components, and system configuration.

Post-Fault Impedance: Calculate the post-fault impedance for each phase. During a fault, the impedance of the faulted path changes, affecting the current flow.

Sequence Impedances: Find the positive, negative, and zero sequence impedances of the system. These sequence impedances represent the impedance seen by positive, negative, and zero sequence currents during the fault.

Applying Symmetrical Component Method: Use the symmetrical component method to calculate the unsymmetrical fault currents in each phase. This involves transforming the fault currents and impedances into positive, negative, and zero sequence components and solving the equations.

Calculation: Finally, use the appropriate equations based