Synchronizing systems

[charlierod]

Is there something like a standard specifying maximun voltage differences before closing breakers when attempting to interconnect two systems?

As far as i'm concerned this depends on voltage level (230 kV is not the same as 4,16 kV). I would like to know if current operating practices applied to our 4,16 kV and 480 V systems will or not shorten equipment life.

Thanks for your comments!

 

[jbartos]

Suggestion: The sought voltage differential is somewhat flexible. It can be specified when you are ordering synchronizing system.

 

[jbartos]

Suggestion: Visit

http://www.beckwithelectric.com

for: Suggested Specifications for Synchronizing Check Relays

 

[rsherry]

You may find in practice the limit is determined by the values that equipment manufacturers are willing to specify or warrant their equipment good for. Most check synch relays (transmission) default to 20 degrees with maximum settings of 40 to 60 degrees. Distribution voltages (33kV and below) can be trickier - air break manufacturers seem less willing to guarantee the equipment if there is an angle across it on opening/closing. A search on 'arcing horns' may yield some useful info for distribution equipment.

 

[Rodmcm]

In general voltage difference is not a problem it is phase difference that gives the problems. On small 480V systems then the voltages are usually only 5-10% difference ( no load to full load voltages on the transformer say), but for higher voltages tap changers can take the range difference well out. It is not unusual to have 5 to 20% taps, hence synchronisers and thier voltage limits to force the operator to rectify voltage difference. The limits of the settings are usually to do with what constraints you have, ie weak systems.