Transient Stability Analysis

The Transient Stability Analysis is done to determine the behaviour of a system during transients or sudden changes in a power system. 

Transients occur when there are power flows from one source to another.  They also occur during faults when a load or a generating point is cut off.  This can cause oscillations in the voltage or power.  Many of these oscillations will quickly get resolved and the system will return to its steady state operation.

However, in certain situations, the oscillations may can increase in severity and can cause fluctuations in the voltage or power which can affect the system and can cause trippings.  Hence, it is necessary to ensure that the system will be stable in the event of a transient.

The stability of a system is classified into

Steady State Stability and
Transient Stability

Steady state stability is the ability of the system to respond to small oscillations in the voltage or slow changes in the load.

Transient stability is the ability of the system to respond to sudden, unexpected changes such as the tripping of a power source or a fault in a tranmission line. 

Transient stability analysis is used in relay setting and in determining the clearing time of breakers.  They are also used to determine the voltage level of a power system and the power transfer capability between different systems.