Synchroniztion

[tavaero]

Hi all

I would like to know the technical reasons for prefering synchronization on MV side of a step up transformer infront of a generator rather than the low voltage side.

Also why it is prefered that when generators start up in case of loss of normal power it is prefered to switch power factor correctors off

Any web site will be an asset.

 

[RalphChristie]

Current lower on MV side of trsf.

 

[Skogsgurra]

Yes, and sometimes/often there's no breaker on the generator side. So it would be difficult doing it on the generator side.

Power correction is switched off because you need the right frequency, phase and voltage to synchronize. The PF controller acts on the excitation, which influences the voltage - that's why you must switch it off (or switch to AVR) to be able to synchronize with the correct voltage.

 

[busbar]

 
Some less sophisticated generator-excitation controls can interact with shunt capacitors in an undesirable manner. The same is true for gensets, capacitors, and some line-sensing capabilities of low-bid UPSs.