Key Interlocks in MV Switchgear

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Anonymous Poster #1	Key Interlocks in MV Switchgear 12/19/2023 10:12 AM
	Can someone explain the operation sequence of these key interlocks in a MV switchgear? Why there is no key in the third lock in the picture?
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33317 Good Answers: 1810	#1 Re: Key Interlocks in MV switchgear 12/19/2023 10:44 AM
	This is a failsafe switch configured to prevent accidental switch engagement...so it depends on your setup... https://library.e.abb.com/public/864a16db4c0d4dcea1d2ac6210ba8c48/CA_POWERCUBE-PBF(EN)F_1VCP000253.pdf https://library.e.abb.com/public/6af12cf0888c4352baf9a917dc4c8cae/Cat_PowerCubePB6_en_DigiPrint.pdf https://library.e.abb.com/public/bd17da3c724f8701c1257b13005738c5/CA_POWERCUBE(EN)C_1VCP000091.pdf __________________ All living things seek to control their own destiny....this is the purpose of life
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raghun Power-User Join Date: Jan 2010 Location: Hyderabad Posts: 343 Good Answers: 22	#2 Re: Key Interlocks in MV switchgear 12/19/2023 10:59 AM
	I believe the subject MV switchgear has two incomers and one bus coupler. The design is such that the two incomers cannot be paralleled. The key interlock ensures that no more than two breakers can be ON at any given point of time. For example, if two incomers are closed, the two keys are locked in the respective positions. Bus coupler can only be closed, if one of the incomers is switched off and the key thus released is inserted in the bus coupler position. This is a positive way of ensuring that the switchgear fault level is not exceeded (by paralleling two incomers) at any given point of time. __________________ Raghunath
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32119 Good Answers: 838	#3 Re: Key Interlocks in MV Switchgear 12/30/2023 7:50 AM
	Yes. The organisation that designed and built it can, and it should have made it available in the Operation and Maintenance Manual for the installation. If it is not to hand for whatever reason than a couple of phone calls to it may well precipitate the arrival of a replacement. The phone number may well be attached to it on a label. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32119 Good Answers: 838	#4 Re: Key Interlocks in MV Switchgear 01/02/2024 6:56 AM
	How did those calls to the equipment manufacturer go, please? __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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gideon Power-User Join Date: Jan 2007 Location: Johannesburg, South Africa Posts: 215 Good Answers: 14	#5 Re: Key Interlocks in MV Switchgear 01/03/2024 1:58 AM
	Some good answers here. Usually your first call for an answer would be to your responsible plant engineer (or even the HV electrician) - they know these things, don't be shy!
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gideon (1); PWSlack (2); raghun (1); SolarEagle (1)

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