what happens when d cexcitation given to alternator is
removed while it is running or what happens when dc
excitation is failed in alternator while running?

Answer Posted / nishad

Generator will not produce any output voltage and it will trip the generator output breaker by the loss of excitation monitor protection relay or under voltage relay. If the breaker not trips by these relay, it will trip by reverse power relay. Due to the presents of Reverse Power relay, it will not allow the Generator to run as an induction generator and will trip the Generator breaker, thus it protect the generator from further severe fault. Again, if it not trips by these all protections, alternator will work as induction generator due to the residual magnetism in the field core when it is running in parallel and it will give the over load to another generator as a result, it will trip entire system. Also, as an alternator typically isn't designed to operate as an induction machine, the windings on these machines will heat up and damage. Therefore, need to make sure the reliability of protection relays to avoid such faults.

Is This Answer Correct ?    3 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What is the requirement of grounding the neutral of single phase generators on load? If the neutral is not grounded, what will be the effect?

1632


What is the Current equation in series RLC circuits.

627


what is is the potential diffrence between two phase ?

5389


How relay works, reverse relay, master relay, os relay, earth fault relay and what is its setting point

1209


why the difference arise between HT reading & LT reading (submeters fixed in complexes, apartments etc)if the power factos exceed from 0.9 to 1 can the ht meter reads fast?

2208






how current is reverse from its normal direction during the fault?

2006


Under wat condition statcom operates as an inductor for the transmission line?

1440


why power not passes in plastic and rubber material

1551


IF 8255 CONTROL WORD IS 94H,Tell the chip port work mode ?

2177


Q.1:What protection will be used on HT and LT side of 33/0.4 KV, MVA transformer. Indicate capacities of protective device to be used. Q.2:Which types of back-up protections are used in the power transformers? What do you understand by the term over travel in the relay? Q.3:How star and delta connected winding transformer are provided from earth fault

1716


What is George phenomena to start the synchronus machine?

3655


Why is water motor not taking the pressure? what is the problem?

1119


We have 90mX100m hangar with 16 no.of supporting pillar. It is required to provide power supply on all pillars. what is suggested earthing scheme for hangars.

1616


what is the min and max ohmic resistance for the earthing rod installed for lighting poles for street light network

3053


If any HVDC line is going with positive & negative(the negative usually have return path of current with earthing electrode). Now the question is if this HVDC earthed electrode which is using as return path and earthed any nearby 400kv or 220kv AC substation equipments. which will be the impact of this on AC substation & its equipment, how severe may be this and what should be the minimum distance require between HVDC earthed electrode and AC substation equipments? It's really an high engineering level question...Dare to answer and increase your knowledge.

1482