Sinosoidal Voltage

For synchronization you need to acheive 1. same voltage phasing and same frequency, then you can close the breaker

Voltage phasing in the sense R to R, YtoY, BtoB. I didnt asked that sir.

If your synchronoscope sensors are misaligned r-r, y-b, b-y for example, then when the feeder comes online you will get reduced power on y and b and increased on r. This is only one of all possible mis-combinations, but perhaps it describes what is happening in your situation. Of course the fault is most likely to be in the instruments connection to the grid, but it could also be a fault within the instrument.

If you are using a synchroscope, then the phasing must be correct if you haven't screwed up the wiring, the only other possibility is that the voltages are badly mismatched.

Cheers

Martin

As I believe Martin said that your voltage and phase must be in Sync, otherwise you will not get the indicated result you need to parallel the two sources. When this occurs there should never be a possibility for a negative half cycle matching a positive half from the second machine. Even a dummy like me has done this numerous times, just using lamps. If you are getting out of sync, something may be really wrong. Do you hsave access to a qualified electrician?

Bill Pilgrim

for synchronization all alternators must have:

1. same frequency

2. same voltage

3. same phase connection, red to red etc...

4. no phase difference between same phases

all the things are done in sync controllers in these days, also in case of synchronoscope assembly we need lamp arrangement which shows that at particular time there is no phase difference between same phases at that particular time we can only turn on the breaker.

Regards,

Baqir Gillani

Observe the following

Phase sequence and stable voltage especially from feeder side

Frequency must be the same and stable

Good voltage regulation by your generator- must have fast response to load demand

Then you cannot make a mistake

NB NO DETAIL IS TRIVIAL IN ENGINEERING- the trivial adds up to a big head ache.

JOSEPH

If you are using a Synchronoscope:

1- ADjust voltage of genset to be the same as the grid, before anything else.

2- Use the synchronoscope to adjust the frequency so that the lamps blinking slows down to zero and lamps go OFF

3- close breaker to grid.

When this is done (and happens), your fequency & voltages will be the same and there will be no opposite cycles as you mentioned: Otherwise, the lamps will not go OFF ALL AT THE SAME TIME! You will not achieve OFF on all the lamps if the condition is not met!

After closing the breaker, the grid will force the Genset to follow and stay synchronised UNLESS the Prime Mover (Engine) fails to keep the speed for any reason (then the reverse current protection should kick in and drop the breaker off the grid). You can still adjust the voltage on the genset after closure of the breaker but not recommended: let the voltage regulator do the job if properly set to share the load...