Synchronism Protection

Dear friend

You need to syncronize two different systems, in order to avoid a circulating current either for phase shift, frequency difference or voltage unmatch.

If those conditions are not reached, large strenghts in your generating machines will occur or either you come into the risk of damaging your transmission line devices, such as the power transformer or even the line itself.

The result will be loss of synchronism between the two systems and consequently separation of them to avoid harm to the components of the systems.

For further good information, please refer to, for instance, the following link:

http://www.selinc.com/techpprs.htm

and look for an adequate paper relating to this matter.

Regards

This is done by a 'sync check relay' (25). But you should make decisions what are the incoming and running sources you have. If you have one source coming from utility and the other source coming from your local generator, the PT signal from the utility shall be the running input to the relay and the signal from the generator bus will be your incoming signal input to the relay. (why the generator is incoming? because for your own generator you have capability to adjust voltage, frequency, etc. parameters, but you will not be able to adjust the utility parameters, so the utility is always be running and the generator side always be incoming).

After programming the relay like the voltage, frequency, dead bus or live bus options etc. when you are in the bandwidth of the matching parameters between the two sources, the relay alows you to close the breaker.

If you are synchronizing between two utility sources it does not matter which one is running and which one is incoming (one will be running and the other incoming). But you do not have any capability to adjust any parameters, except to make sure the phase reversal situation. always you will depend on the utility incomings to close the breaker. If you are the big customer to the utility they will help you to match the two incoming lines.

For more information go to the basler web site, or any other sync-sheck relay manufacturer.