27-12-2012, 06:58 PM
Auto-Reclosing On Transmission Systems
Auto-Reclosing On Transmission.ppt (Size: 476.5 KB / Downloads: 105)
1 Higher power transfer limit.
2. Reduced power swing amplitude.
3. Reduced switching overvoltages due to reclosing.
4. Reduced shock to generators. Sudden changes in mechanical output are less
High Speed Auto-Reclose
1. Single transmission links.
2. 3Ø A/R.
3. 1Ø A/R for E/Fs
Lockout for multiphase faults.
4. 1Ø A/R for E/Fs
3Ø A/R for multiphase faults.
1. Separate control of circuit breaker poles.
2. Protection must provide phase selection.
3. Mutual coupling can prolong arcing and require de-ionising time.
4. Unbalance during dead time
(i) Interference with communications
(ii) Parallel feeder protection may maloperate
5. More complex and expensive than 3Ø A/R
Protection
High speed not critical for system stability
desirable to limit fault damage
improves probability of successful A/R
Dead Time
Allow for power swings and rotor oscillations to die down.
Different settings for opposite feeder ends.
Typically 5 to 60 secs.