In our power plant we are using CAT diesel generators for generation. Now we are facing problem in auto synchronization of the grid through Woodward MPU2 multifunction relay. The voltages,phase difference and frequency are exactly same with the grid but synchronization is not happening with the grid and no errors. The same multifunction unit is working on the other engines, but it was not allowing to synchronize on one particular engine. We had checked all the parameters and found that there is one missing output at terminal 15 of multifunction unit. For the output from relay we had checked all the conditions and found it is intact and also checked all the signals from relays and everything is intact. But we are unable to synchronize with the grid.
When did this problem start?
Had the module been working for some time previously and then just stopped working?
Did some event (trip) occur just prior to the start of the problem?
Many times there are other permissive or conditions which must be satisfied before the synchronization module output can get through to the breaker Close coil. If you have a schematic drawing of the generator breaker close circuit have you verified all the contacts (permissives) in the entire circuit?
Was some work done on the synchronization circuit (breaker close circuit; VT (or PT) or CT circuits)?
Have you verified the synchronization module contacts close at the appropriate instant during the synchronization attempt?
Please write back to let us know what you find!