The most serious consequence of a major uncleared short-circuit fault could be fire.
All the three phases-to earth
The results in a symmetrical fault is All the three phases-to earth.
Overhead lines of the transmission system is more prone to faults.
Alternator of the power system is least prone to faults.
Both (a) and (b)
The magnitude of fault current depends upon Total impedance up to fault and Voltage at the fault point.
The most common type of fault is Single-phase-to ground.
Three-phase bolted fault
The maximum short-circuit current occurs in the case of Three-phase bolted fault.
Bring down the fault level within the capacity of the switchgear
Series reactors are used to Bring down the fault level within the capacity of the switchgear.
Any of the above
Current limiting reactors may be the following types 1. Air-cored air-cooled, 2. Oil immersed magnetically shielded, 3. Oil immersed non-magnetically shielded.
Unbalanced 3-phae fault
Symmetrical components are used in power system for the analysis of Unbalanced 3-phae fault.
In a star-connected system without neutral grounding, zero sequence currents are Zero.
Positive-sequence currents only
A balanced 3-phase system consists of Positive-sequence currents only.
Equal to Negative sequence current
The Positive sequence current of a transmission line is Equal to Negative sequence current.
Positive and Negative sequence impedances are equal.
For a fully transposed transmission line Positive and Negative sequence impedances are equal.
Only (a) and (b)
The negative-and zero-sequence voltages are maximum.
All sequence networks are connected in series.
Double-line-to ground fault.
Zero sequence fault current is absent when fault is Double-line-to ground fault.
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