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Control vs Relay Panel

03/21/2017 10:31 AM

In high voltage systems, say 220kv, the relays are all mounted in one cubicle called relay panel while the associated control, indication, and measuring instruments are mounted in a separate panel (called the control panel). This scheme is called duplex scheme. I need to know why people do not use just one panel for all functions associated with one specific protection. Any restriction besides one large cubicle?

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#1

Re: control vs relay panel

03/21/2017 10:45 AM

Is this you?

You are so clueless that you are dangerous to others.

Why don't you try for a safer job like traffic guard.

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#7
In reply to #1

Re: control vs relay panel

03/21/2017 11:14 PM

Maybe another potential Darwin Nominee looking for a quicker way to win the Award?

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#2

Re: control vs relay panel

03/21/2017 11:17 AM

On the drawings, documents and commissioning records marked "as built" for the specific installation, which the facility must surely have otherwise maintenance activity would become fraught with difficulty, are the initials if not the names of the people who carried out the design, construction and commissioning of the installation. These are the people to ask. With a bit of luck the telephone number of the organisation that carried out the work will be there too and if one cannot find those specific individuals using the telephone, one ought to be able to find a few follow-on Designers who know about this stuff that can help. So, make the call(s).

None of the drawings can be seen from here, so the forum will find it rather difficult to carry out this investigation.

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#3

Re: control vs relay panel

03/21/2017 11:35 AM

The forum doesn't even know in which country this installation will be found, never mind which suite of local electrical regulations are applicable. So it's not fair asking a bunch of anonymous strangers these sorts of questions.

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#8
In reply to #3

Re: control vs relay panel

03/22/2017 4:32 AM

He’s in Sri Lanka, far enough away from me to not worry.

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#10
In reply to #8

Re: control vs relay panel

03/22/2017 11:31 AM

Some might worry that the Border is permeable.

<unsubscribes>

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#4

Re: control vs relay panel

03/21/2017 1:12 PM

Remember the 13th commandment: Thou shalt not wipe out the PLC's memory with an EMF blast from thy high voltage contactors.

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#6
In reply to #4

Re: control vs relay panel

03/21/2017 1:14 PM

"But Mama, that's where the fun is..."

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#5

Re: control vs relay panel

03/21/2017 1:14 PM

As a general rule, the term "relays" used in the context of HV systems means protective relays, the term "control" generally refers to SCADA control. If you had them in the same cabinet and something went bad in the SCADA control equipment, it might damage or adversely affect the protective relays, which are your first (and often last) line of defense against catastrophic failures.

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#9
In reply to #5

Re: control vs relay panel

03/22/2017 8:10 AM

Really, SCADA?? From the wording of the original post, I doubt seriously whether this system he describes has anything close to a SCADA system and predates that by many years. It sounds like a description of a much earlier manual system. My guess is that the "relay panel" is in the substation yard in a small building with other protective relays and that the "control Panel" is in another small "operators control building" The protective relays are not that dangerous. The reason for the separate "control panel" is that if there are very many items to control the building or room would simply get to large. If the installation is small, just one or a few items to control, the Control panel and Relay panel might be side by side or across the room from each other. Most time the operators control room is somewhat conditioned environment and limiting that area reduces the amount of energy required to keep it cool or warm.

Far more of the world exits without SCADA, than with it, even here in the US. Sorry, but that is a fact. If you doubt it, you really don't have much experience in the real world.

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#13
In reply to #9

Re: control vs relay panel

03/22/2017 3:29 PM

Most modern power plants will have a sufficiently scaled control room to facilitate all controls and protections in a controlled environment of temperature and humidity.

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#11
In reply to #5

Re: control vs relay panel

03/22/2017 1:30 PM

Also, you may not want your relay calibration technician opening cases and drawout plugs and connecting test plugs in front of a switch that can plunge an entire town into darkness. Also older relays had many mechanical components, delicate bearings, spindles, where a mechanical shock could make a protective contact close. So the operators were kept to a separate panel where they could minimize contact with the protective devices.

I've put operations on one side, protection on the other, especially to reduce clutter for operators to figure out which breaker to throw.

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#12
In reply to #5

Re: control vs relay panel

03/22/2017 3:27 PM

As an expansion (or contraction) of what you have stated:

The relay cabinets are there to protect life, and to protect property. They act to open field breakers, shut down the prime mover, etc., purely on an emergency basis, and are isolated from electric faults, ground currents, voltage transients from other switches, and from RF interference for a damn good reason. Things are "twitchy" enough without tacking on a whole laundry list of false trips.

The control panel has its own specific functions, and has modules within the range of control functions specific to the type, size, model, and class of the prime mover operating unit. I am surprised that coolyaar would actually pose such a question.

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