Question

In a power system, which of the following is/are critical clearance time of a fault related to?

1. Transient reactance

2. Sub-transient reactance

3. Reactive power limit

4. Transient stability limit

1. 1 and 2
2. 2 only
3. 3 and 4
4. 4 only

Answer 1

Correct Answer - Option 4 : 4 only

• The critical clearance time of a fault is related to maximal fault duration for which the system remains transiently stable.
• Transient stability means the ability of a power system to experience a sudden change in generation, load, or system characteristics without a prolonged loss of synchronism.
• To maintain transient stability, a power system fault must be cleared quickly enough so that the fault on transient remains inside the stability boundary.
• The critical clearing time exceeds, stability is lost by generators using synchronism.