B

From what I can tell reading the old elementaries, the frequency window was >.12hz and <.24hz differential as compared to line frequency which correlates to a window >100.2% speed and <100.4% speed (assuming line freq was 60hz). FSNL setpoint was 100.3% speed so that falls right in the middle. I realize that you want to synch a little fast but this seems a little too fast.

With our new control system, the time to auto-synch after FSNL takes much longer than it used to(30-40 seconds). The new freq window is >0hz and <.1hz differential as compared to line freq. This correlates to a window of >100.0% speed and <100.17% speed. FSNL setpoint is 100.1% speed which barely falls into this window and sometimes requires speed decreases to satisfy the auto-synchronizer.

My main question is: Is it safe to synchronize these units at a frequecy as much as .2hz above line frequency. It seems that it was doing that for 25 years before we replaced the control system. Can this be allowed because they are such small generators(80 mw)? I would like to widen our frequency differential window to >0hz and <.2hz on our new system to allow a faster auto-synch.

Basically we would still auto synch at 100.1% speed or 60.06hz (assuming line freq is 60hz) but a wider window will hopefully eliminate speed decreases. Thanks for your help.