Wind turbine generator protection

[Hoxton]

There is (to me) an interesting post in the Engineering Failures and Disasters forum, concerning a major grid blackout in Australia.

http://www.eng-tips.com/viewthread.cfm?qid=418158

It seems that wind turbine generators have protection on Fault Ride Through - Specifically Low Voltage Ride Through which trips the unit after successive fault events.

Questions:

1. Is this correct?
2. Is this specific to any generator / turbine types? I am specifically thinking of DFIG (Double Fed Induction Generators)
3. What reasons are there for this?

In my spare time, I am the Technical Secretary of the Association of Manufacturers of Power Generating Systems (AMPS) in the UK and this is relevant to our discussions on the RfG (requirements for Generators) Directive. AMPS is a sister organisation to EGSA in the USA

 

[Parchie]

DFIGs have weak fault ride-through capability compared to synchronuous generators. If your protections are set quick enough to isolate faulted sections, before the induction generators in the grid demagnitize, it is possible for those DFIG to re-excite successfully.

It is also important that these DFIG have loads in their area so that capacitances in the loads help in the re-excitation. The necessary, well-thought of fault ride-through settings of your system also helps.