VSDs stoppage after supply disturbance 1

[SA07]

Hi
Can you plz share what is done to avoid loads on VSD to stop/trip after a disturbance on the supply voltage?
We have several turbo-alternators + boilers connected to the national grid. Usually a disturbance on the grid causes VSD to stop/trip. We have set VSD with 3 restarts after fault, restart after power failure. But still sometimes we have some trips e.g on fans, coal feeders VSD. On compressors also we have this issue. Are there special VSD which can tackle this problem?
Whenever a critical VSD stops, the whole plant will stop. Thks

 

[RRaghunath]

VSDs do come with 'Voltage dip ride-through' and 'flying start' functions.
It may just be a matter of enabling and setting the already-available feature in the VSD.
Capture the voltage disturbance plot and discuss with the VSD vendor.

 

[LittleInch]

What sort of "disturbance"??

How big is the volt drop / frequency dip / seconds of lost power?

Is it the VFD or the switchboard itself which drops out the incomers?

There are some which no system can withstand.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[jraef]

First you must define "disturbances". Over voltage swells? Under voltage sags? Total power losses? Brief power losses, as in 2 seconds or under? What you are seeing determines how you approach a solution.



" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[SA07]

Plz see attached a doc with recordings and comments.

 

[RRaghunath]

The plot shows voltage dip was only for 100ms at the upstream 66kV bus due to an earth of fault in Blue phase.
It can be solved by enabling/setting the voltage dip ride-through feature in VSDs. As I mentioned in my previous post, approach VSD vendors with the details for support.

 

[jraef]

Not all VFDs offer that feature though, so it will depend on the brand and model.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden