Methods to Improve Transient Stability

Transient Stability:

Transient Stability is the ability of the power system to maintain the synchronism after the sudden large disturbance. These disturbances may be because of the application of faults, clearing of faults, switching ON and OFF surges in EHV system

Transient Stability Improvement methods:

• Transient stability of the system can be improved by increasing the system voltage. Increase in the voltage profile of the system implies increase in the power transfer ability.This helps in increasing the difference between initial load angle and critical clearance angle. Hence increase in power allows the machine to allows to rotate through large angle before reaching critical clearance angle.
• Increase in the X/R ratio in the power system increases the power limit of the line. Thus helps to improve the stability
• High speed circuit breakers helps to clear the fault as quick as possible. The quicker the breaker operates, the faster the fault cleared and better the system restores to normal operating conditions
• By Turbine fast valving: One of the main reason for the instability in the power system is due to the excess energy supplied by the turbine during the fault period. Fast Valving helps in reducing the mechanical input power when the generator is under acceleration during the fault and hence improves the stability of the system
• Use of Auto Re-closing: Majority of the faults in the power system will be momentary and can be self cleared.  Hence circuit breakers employed for fault clearance opens in sensing the fault with time delay of 2 cycles and re-closes after particular time to determine whether the fault is cleared. 
• Some of the other ways to improve the transient stability are by employing lightning arresters, high neutral grounding impedance, single pole switching, quick Automatic Voltage Regulators (AVRs).