Question

Stability of power system can be improved by

1. Using series compensators

2. Using parallel transmission lines

3. Reducing voltage of transmission

Which of the above statements are correct?
1. 1 only
2. 2 only
3. 2 and 3
4. 1 and 2

Answer 1

Correct Answer - Option 4 : 1 and 2

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
• High speed circuit breakers help to clear the fault as quick 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 of a power system is

\({P_{max}} = \frac{{EV}}{X}\)

We can increase the steady state stability by decreasing the reactance X. In double circuit line the reactance is less than the single line circuit.

 

Series capacitors are used to compensate for the inductance of the transmission line. They will increase the transmission capacity and the stability of the line. These are also used to share the load between parallel lines.