Relays at the breaker or in the control house?
Relays at the breaker or in the control house?
(OP)
Does anyone have some good references about why it is better to have relays in the control house than at the breaker?
I figure having it in the control house is better so that emergency maintenance on the breaker can happen safer and faster during rain or other inclement weather. Also I have doubts about microprocessor relays performing well in outdoor cabinets which could easily be exposed to water (especially if the cabinet isn't closed properly) or to extreme temperatures.
But construction sometimes sees the control house as an unnecessary cost (like when upgrading an old substation to microprocessor relays) so I'll need to make my arguments tighter. Or maybe I'm being overly concerned?
I figure having it in the control house is better so that emergency maintenance on the breaker can happen safer and faster during rain or other inclement weather. Also I have doubts about microprocessor relays performing well in outdoor cabinets which could easily be exposed to water (especially if the cabinet isn't closed properly) or to extreme temperatures.
But construction sometimes sees the control house as an unnecessary cost (like when upgrading an old substation to microprocessor relays) so I'll need to make my arguments tighter. Or maybe I'm being overly concerned?






RE: Relays at the breaker or in the control house?
You don't found some reference on the issue.
Your reasons are right reasons.
From other hand, GE show connections of the digital relays in the field.
From my point of view, protective relays must be in the control room.
Best Regards.
Slava
RE: Relays at the breaker or in the control house?
The micros we have in outdoor breaker cabinets have seemed to fair really well to date, but we always have heaters in the cabinets.
Alan
RE: Relays at the breaker or in the control house?
The addition of a wireless transceiver to breaker control cabinets with microprocessor relays could help with some maintenance during inclement weather. Some things could be done with a laptop computer in your truck.
RE: Relays at the breaker or in the control house?
I don't often see transformer protection relays located outside at substations, but feeder breaker relays outside is not uncommon. I'd not be too concerned about the microprocessor relays as long as the enclosures are kept non-condensing via space heaters.
This is also often a function of local climate.
David Castor
www.cvoes.com
RE: Relays at the breaker or in the control house?
I'm a relatively new protection engineer (three years). As we replace aging equipment and upgrade substations, there is often a discussion of whether we should put in a control house. It's good to see a few opinions on the matter.
RE: Relays at the breaker or in the control house?
RE: Relays at the breaker or in the control house?
The electronic reclosers work well, as long as someone dosen't leave the doors open. However, each recloser contained a battery, which needed maintenance, and replacment every 5 years.
The building allows more space, and easer access where more equipment is needed, such as for transmission panels, and relays, and comm gear.
On small substations it maybe possible to do without a building, but it may take a dozen or more boxes to do it.
RE: Relays at the breaker or in the control house?
In the US, tax treatment is different between a building and a piece of equipment. Buildings have a 20-30 year write off and pay property taxes, permits, etc. Equipment is written off much faster and may pay less property taxes be easier/faster to get building permits.
A small substation can afford a control enclosure with room for expansion when it can't afford a building.
One advantage of placing a microprocessor relay in the breaker or transformer control enclosure is it can act as a remote I/O for other alarms and status without having to pull more wires, assuming there is a communication link. For example, the relay might monitor SF6 pressure, spring charge state, operations counts, control box temperature, local/remote selector switch position, disconnect switch status, transformer tap position. Control power status, etc., etc. Wiring is all in the CB panel with a fiber back to a SCADA communication hub. Not much field wiring.
Things to think about as you decide chocolate or strawberry or tutti-frutti.
RE: Relays at the breaker or in the control house?
RE: Relays at the breaker or in the control house?
On breaker and a half schemes it would require CTs from one breaker to run to another breaker. Right now most of our breakers are fairly interchangeable, so it would require a different spare parts stratagy if each breaker was customized with relays, test switches and interconnected lockouts.
Living in western Washington, having instrumentation technicians working in the rain/weather would be pretty big change.
RE: Relays at the breaker or in the control house?
One must also always look at the application to determine what is the best overall solution.
I always prefer to have an indoor switchboard with the diffs and station OC protection/lockouts there and leave the feeder breakers completely local with respect to CT's and relay control circuits. Why....because that is my preference up front. Having said that, my most recent station did not allow for that....so it can depend on the application as well as the budget.
But with all else being equal, it still most often boils down to individual design preference.
Alan
RE: Relays at the breaker or in the control house?
RE: Relays at the breaker or in the control house?
RE: Relays at the breaker or in the control house?
RE: Relays at the breaker or in the control house?
h
RE: Relays at the breaker or in the control house?