DG Set Synchronization with Grid

A lot of things could be wrong. The alternator voltage must be equal to the bus voltage. Both the frequency and phase must be matched between the alternator and bus. If done properly (voltage, frequency, and phase) there should be very little current or KW when the alternator is connected.

Has the alternator recently been serviced? I once saw a case where the phases were not properly connected after servicing and the rotation was reversed.

Is this is a new installation, has the machine undergone any maintenance, or has it operated correctly in the past?

How do you know these are circulating currents; i.e., where are they circulating between? Are there any other local generators that are also running on the mains bus? What is the vector group of the transformer, how is the equipment grounded?

What happens after 10 seconds; normal operation, unit trip, voltage settles, etc???

When connecting after synchonising, you may have the voltage too high and you are taking too much sudden load. The prime mover might be complaining.....

Thats about all I can think of.

What is indicating the circulating current of 500 amps?

See that little knob over there? Turn it about 10 degrees to the left.

My left or your left?

What if I push it in or pull it out?

How about if I just jiggle the handle a bit like when the toilet sticks?

What's the company safety procedure book say?

Or what would that old engineer guy they fired last week because no one in upper management could figure out what he did here, but knew how everything worked, say to do?

Unless you're inside the panel looking out, your left and mine will be the same. I have yet to see a push/pull or up/down genset control pot, but who knows?--I am no longer currently in that field (please excuse puns.)

Simply, <..we...> do not know what <...we...> are doing, because instead of having a qualified Electrical Engineer on site, <...we...> have chosen to go to an anonymous international Engineering forum instead.

Synchronising generator sets is proverbially "nothing new under the sun", nor is it the much acclaimed proverbial "Rocket Science". So, as the installation cannot be seen from here, consult a qualified Electrical engineer locally.

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