What is the max. allowable phase difference between two sources before synchronizing (parallel operation)? If a quick transfer device is used for changeover, is there a condition for max. phase difference?
2006-11-17 21:07:23 · 2 answers · asked by ehab_ibraheem 1 in Science & Mathematics ➔ Engineering
As already mentioned, the maximum phase angle difference is dependent on the device; however, it is ALSO dependent on the "stiffness" of both the system and the generator being switched on.
A large, stable electrical grid can tolerate a generator coming online with a larger phase difference, because the system will "pull" the generator into line with itself. If the generator is significantly large compared to the system, though ... both will go offline.
It is not uncommon to require that a generator be within a limit of phase difference around +/- 0.5 degrees (electrical) before switching into the grid. Some discrete locations will allow more (Hoover Dam is one).
If you're trying to do this by matching up a pair of dials by eye, really try to get them spot on before closing the switch!
2006-11-17 23:50:49 · answer #1 · answered by CanTexan 6 · 0⤊ 0⤋
It depends on the equipment and how much surge it is capable of absorbing without damage. At Hoover Dam they manually align to within 1 degree before dropping the generator across the mains. And a 1 degree phase difference makes the entire generator building 'twitch' when the generator is switched online. It's real impressive and it gives you a whole new appreciation for the amount of energy involved âº
Doug
2006-11-18 05:40:18 · answer #2 · answered by doug_donaghue 7 · 0⤊ 0⤋