This preview shows page 1. Sign up to view the full content.
Unformatted text preview: of short-circuit current determines the size of the protective reactors which
must be inserted in the system so that the circuit breaker is able to withstand the fault current.
(iv) The calculation of short-circuit currents enables us to make proper selection of the associated apparatus (e.g. bus-bars, current transformers etc.) so that they can withstand the forces
that arise due to the occurrence of short circuits. 16.8 Faults in a Power System
A fault occurs when two or more conductors that normally operate with a potential difference come in
contact with each other. These faults may be caused by sudden failure of a piece of equipment,
accidental damage or short-circuit to overhead lines or by insulation failure resulting from lightning
surges. Irrespective of the causes, the faults in a 3-phase system can be classified into two main
categories v iz.
(i) Symmetrical faults (ii) Unsymmetrical faults
(i) Symmetrical faults. That fault which gives rise to symmetrical fault currents (i.e. equal
View Full Document
This note was uploaded on 11/12/2012 for the course MBA 101 taught by Professor Muhannad during the Spring '12 term at Bradford School of Business.
- Spring '12