kana Posted July 22, 2009 Report Share Posted July 22, 2009 Hi, I'm working in small power plant where 4 low voltage generators rated at 625kVA, 415V, 50Hz will operate in parallel. The neutral of each generator is connected via a reactor (reactance 86ohm) to common neutral busbar. Can someone please tell me what is the use of this reactor? Regards, Kana Link to comment Share on other sites More sharing options...
Clayts Posted July 25, 2009 Report Share Posted July 25, 2009 This makes for a good read http://www.qualtecheng.com/ngrdrx.htm Your job sounds interesting..wanna swap Link to comment Share on other sites More sharing options...
kana Posted July 26, 2009 Author Report Share Posted July 26, 2009 Hi Clayts, Thanks for the information. It was stated that the neutral reactor is used to reduce earth fault and 3rd harmonics current. Isn't this applicable only for high voltage generators? I'm not sure with this. If the phase voltage of a 3 phase low voltage generator is 240V and the neutral reactance is 86 ohms, the fault current would be 240/86 = 2.79A. This fault current is too low that a 6A MCB could not even trip. How can a 1000A Air Circuit Breaker with an earth fault relay set at 10% of rated current trip for such a small fault current? Isn't that going to be dangerous to operate? Regards, Kana Link to comment Share on other sites More sharing options...
Clayts Posted July 26, 2009 Report Share Posted July 26, 2009 Hi Kana. Sorry, I don't know the specifics of your reactor and can't give you an answer. I thought your generator/s where greater than 400VAC and in parallel.? Why bring up 240V and a 1000A ACB? This topic is out of my league, I'm quite specific to electric motors in a very practical sense. Hopefully somebody else can answer your question. Maybe I'll learn something new also. After all, thats why I frequent this site. Clayts Link to comment Share on other sites More sharing options...
kana Posted July 28, 2009 Author Report Share Posted July 28, 2009 The generator is rated at 415V phase-phase and 240V phase-neutral. 1000A is the size of the ACB. Hope someone could clear my doubt. Link to comment Share on other sites More sharing options...
kana Posted August 4, 2009 Author Report Share Posted August 4, 2009 Hi, Anyone have any idea of the generator neutral reactor? Regards, Kana Link to comment Share on other sites More sharing options...
tioga Posted January 11, 2016 Report Share Posted January 11, 2016 The neutral reactances are used to prevent circulating currents in the neutrals of generators operating in parallel. Circulating currents are caused basically by different winding pitches.The best answers you can get is to "Google" "Neutral Reactor". You will find an entire education on neutral reactors with excellent "White Papers". Tioga "USS Hornet" Link to comment Share on other sites More sharing options...
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