What are Transients in a Power System?

What are Transients in a Power System?

Transient can be stated as the phenomenon’ when the change is significant but the duration of the change is not much’. But they are very important for power system because depending upon the intensity of the transient, fault occurrence in a network can be severe or less severe.

Transient phenomenon can be understood more easily by this instance. Any change in system network cannot take place instantaneously, some time is needed for this change. For example voltage build up across a circuit is not instantaneous, it needs some time to reach the peak value, and this period is known as transient period.
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Suppose a network is normally charged and carries load and suddenly a fault occurs. Then the main switch is closed or opened, this redistribution bound upon transient period, depending on which the severity of the fault is determined. Three facts makes this more understandable:

Current cannot change instantaneously.
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Voltage across a load cannot change instantaneously.
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Law of conservation of energy holds good for the compounds which stores energy (Inductors, Capacitors) and the transient phenomenon is widely seen on them.