Tie Breaker Used In Power Control Center Arrangement

6 comments

Rate

Anonymous Poster	Tie Breaker Used In Power Control Center Arrangement 01/10/2011 5:02 PM
	I have seen PCC with tie breakers NC. This one is depicted as NO. What would be the advantages of doing one or the other. Also, how having this tie breaker is better than not having one at all? Any references, opinions etc are welcome. Primary voltage is 4.16 kV secondary voltage 480 (At the PCC where the tie is located) Secondary feeders provide power to Distribution boards, MCC etc.
	Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

These comments received enough positive votes to make them "good answers".

Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#1 Re: tie breaker used in power control center arrangement (load side of TX in picture 01/10/2011 5:19 PM
	It depends on the installation. If the transformers are to be paralleled, they need to be the same (or at least compatible) vector group, so that they will be in phase. If not, the bus tie breaker needs to be interlocked with the other two so that it can be closed only when one of the others is open. There are many cute slider-bar tricks for doing this mechanically among various breaker combinations. If one transformer is down, the bus tie allows a subset of loads on either side to run on the remaining transformer. __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
	Reply

kwcharlie Power-User Join Date: Jan 2010 Location: Houston off/on-shore @ Oil Patch Posts: 223 Good Answers: 2	#2 Re: tie breaker used in power control center arrangement (load side of TX in picture 01/10/2011 5:47 PM
	OR the load can be split between the two transformers/generators when the tie is open. This is usually done for a ship with an infrequent high load mode (like jacking) that is divided with two HPU's on each MCC and the TIE Breaker open when all 4 HPU's would overload a single Feeder __________________ Why do they make manhole covers round? so they won't fall in [before asking "Who is John Galt?"]
	Reply

kvsridhar Guru Join Date: Sep 2009 Location: Temporarily at Ashburn, VA Posts: 2744 Good Answers: 164	#3 Re: Tie Breaker Used In Power Control Center Arrangement 01/10/2011 8:48 PM
	Two good answers. Additionally, my thought is that a Circuit Breaker is a protective device and will do its function of protecting when it is ON, and will trip very quickly in the event of a fault. So, i would rather use it in the Normally Open mode. __________________ Nothing worthwhile can ever be taught, it can only be learnt.
	Reply

vijaymail_electrical Commentator Join Date: Jan 2011 Location: India Posts: 98 Good Answers: 2	#4 Re: Tie Breaker Used In Power Control Center Arrangement 01/10/2011 11:08 PM
	it may be indicating that it can be closed when only one incomer is closed. Its similar to interlock scheme of 2 incomer+1 B/C. If two incomers are closed, it is not necessary to share the load. __________________ You don't understand anything until you learn it more than one way.
	Reply

ramvinod Guru Join Date: Jun 2007 Location: chennai,India Posts: 592 Good Answers: 19	#5 Re: Tie Breaker Used In Power Control Center Arrangement 01/10/2011 11:25 PM
	This type of Distribution arrangement is followed for continuous process industry/Software parks/Data centers.. The transformer and PCC is designed for Full load of the Plant.But in operation Both the transformers/ Incomers will be kept on with tie breaker off.Each of the transformer is partially loaded In case of emergency ,transformer maintenance or failure, tie breaker will be made on and one transformer will feed all sections of the load. Generally, parallel operation of two transformers is avoided , as otherwise the short circuit capacity of the switch gear ,PCC and down stream Switch gear to be increased. It is a practice to have interlock the three breakers (2 incomers and one Tie ) such that only any two breakers can be switched on. __________________ Ramesh,Freelance Electrical/automation Consultant
	Reply Good Answer (Score 2)

kvsridhar Guru Join Date: Sep 2009 Location: Temporarily at Ashburn, VA Posts: 2744 Good Answers: 164	#6 In reply to #5 Re: Tie Breaker Used In Power Control Center Arrangement 01/11/2011 3:23 AM
	That is quite correct. GA. __________________ Nothing worthwhile can ever be taught, it can only be learnt.
	Reply Off Topic (Score 5)

These comments received enough positive votes to make them "good answers".

Copy to Clipboard

	Got Something to Say?
	Ask a Question Start a Discussion

	Aerospace
	BioMech & BioMed
	Chemical & Material Science
	Civil Engineering
	Communications & Electronics
	Education and Engineering Careers
	Electrical Engineering
	General Discussion
	Instrumentation
	Manufacturing
	Mechanical Engineering
	New Technologies & Research
	Software & Programming
	Sustainable Engineering
	Transportation

	Site Directories
	Forum Directory Blog Directory User Group Directory RSS Feeds CR4 Rules of Conduct CR4 FAQ Site Glossary Who's Online (110 right now) Show Members