Correct Answer - Option 2 : Transient stability
Transient stability: Transient stability is the ability of the power system to maintain synchronism when subjected to a severe transient disturbance.
Transient stability of the system can be improved by
- Increasing the system voltage
- Increase in the X/R ratio
- Using high-speed governors on machines
- Series capacitance
- Excitation control
- High-speed circuit breakers help to clear the fault as quickly as possible
- By turbine fast valving
- High-speed excitation
- Use of auto re-closing breakers
- 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).
Steady-state stability limit = \(\frac{{{V_1}\;{V_2}}}{X}\)
More steady-state stability represents more transient stability of the system.
Steady-state stability limit of the system can be increased by the following methods:
-
Upgrading voltage on the existing transmission system or opting for higher voltages on the new transmission system.
-
The use of an additional parallel transmission line reduces transfer reactance X, thereby increases it.
-
The use of a transformer with lower leakage reactance improves a steady-state stability limit.
- Series capacitive compensation of transmission line reduces transfer reactance X and hence steady-state stability limit increases.
-
The use of bundled phase conductors reduces the reactance thereby increasing the stability limit.
