Question

In order of frequency of occurrence of short-circuit faults in three-phase power systems, list those: ________, ________, ________, ________.

Short answer

Answer

Single line-to-ground, line-to-line, double line-to-ground, balanced three-phase faults.

Step-by-step solution

Definition of short-circuit faults.

A short circuit faults is defined as the condition when an electric current does not pass through any wiring of the system of equipment because current choose a shorter path to flow, in this case the current flowing is of large amount and can damage whatever equipment comes in the conduction path.

Determine short-circuit faults in three-phase power systems.

In a three phase power system the highest frequency is of single line-to-ground fault due to ionization of air or physical touching of transmission lines. Second most occurring fault is short-circuit fault occurring in line-to-line due to lightning strikes or physical contact. Third kind of short-circuit fault occur in double-line-to-ground fault due to dust storm or flood coming. At last short-circuit fault occur in balanced three-phase faults due to all three lines being shorted to ground.

Therefore, theorder of frequency of occurrence of short-circuits faults in three-phase power systems is Single line-to-ground, line-to-line, double line-to-ground, balanced three-phase faults.