Concept of manual control in the AVR of Generator

[PAP]

Dear All
I've ever known that some excitation systems can switch from automatic voltage regulator(AVR) operation to manual control operation when the main controller of AVR is failed. Please give me any suggesstions about this concept and applications used.
Thank you
PAP

 

[jbartos]

Suggestion: Visit

http://www.cim-logic.com/cimu09a/Logical_View/Wires/SynchronousMachine.html#aVRToManualLag

http://www.kestrelpower.com/Docs/doc20951128452.pdf

http://www.basler.com/downloads/altrxfly.pdf

etc. for more info

 

[jwerthman]

The manual regulator is a DC regulator that keeps the DC field current at a constant value. It is a way of continuing to run a generator if the AVR has failed. However, if the load is varying, an operator must manually adjust the excitation to keep the terminal voltage constant (or the vars or power factor constant if operating in that mode). Modern exciters and regulators should include automatic tracking functions to keep the DC regulator in step with the AVR so that if the AVR fails and the exciter transfers to the manual DC regulator, there is no significant change in excitation to the generator. Older machines generally have a transfer voltmeter that compares the DC regulator output to the AVR output and allows an operator to manually keep the DC regulator in step with the AVR.

 

[bigamp]

A manual regulator is of most use during generator testing and commissioning. If you need to do a short circuit test you can gently turn on and apply excitation with a manual system, not all automatic systems will allow this.

It is also desirable to use the manual excitation system for the first synchronising of the generator, mostly to keep it simple and one less automatic system to go wrong!

Other than for commissioning, you would normally always use the automatic system.

Regards

 

[PAP]

As jwerthman (Electrical) explained ,I'd to ask for additional information as follow:
-What're the inputs of DC regulator which work parallel with the AVR, and how it work (What's "in step with the AVR&quot?
- In the old AVR system which have the main control unit only ,can it be modified to add this function for more reliability.

Thank you everybody for this chance.
Regards
PAP