GOAB on Transmission Line

[s1490]

I am the structural transmission line design engineer for my utility. For the first time, we will be using a 3-way GOAB at one our taps as part of a rebuild. I reached out to Protection and Control, as well as Communications for a recommendation on the switch as electrical/comms wasn't my forte, and figured I'd design a pole to hold whatever they recommend and handle the structural loads.

They came back and said they did not really have anything to do with that. I figured modern GOAB's could have some SCADA integration or some other uses applicable to protection or comms.... is that not the case?

 

[Paulsey88]

Definitely a thing. Modern GOAB's can be fitted with motor operation(MOAB) and can be remotely operated. You can also install metering/SCADA only equipment and feed that into protection and supervisory systems. Tons of factors, tons of choices. The Utility I work the most for rarely installs motor operated. Meanwhile the rural electric co-ops and transmission/generation co-op that feed them use MOABs w/ remote operation all the time. Differing philosophies and resources.

 

[cuky2000]

SCADA integration is an optional feature that can be implemented in any disconnect switch for remote operation, monitoring and/or status.

Often, three-way switches (3-way GOAB. click Link for illustration ) are used for line taps, ties, and sectionalizing. Phase-over-phase arrangements are especially helpful where restricted right-of-way or difficult terrain makes another switch/structure configurations unworkable.

From the structural perspective, this can be installed in appropriate wood, concrete or steel pole. If misalignment is an issue, there is an option to have the switch assembly in a steel C-channel and them bolted to the pole.

 

[Mbrooke]

They may have remote control or they may not. Depends on their purpose.

 

[crshears]

I had to Google this to confirm it wasn't the Grandmother Of All Bombs...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[jghrist]

I had to Google this to confirm it wasn't the Grandmother Of All Bombs...

If it was remotely controlled, it would have to be motor operated. Then it would be the Mother of All Bombs (MOAB).

 

[crshears]

Some people's kids...

What does the OP call transmission voltage? My utility once used a GOAB at 230 kV to split a circuit with multiple dual supply tapped stations on it, the idea being to reduce the impact to our customers from circuit outages by 75%; only half of the stations would be on a single supply instead of all of them, and since the work was performed with two separate outages instead of one big one the exposure duration was cut in half for each. Our Protection and Control department would work out in advance what needed to be done as far as making zones instantaneous, blocking transfer/remote tripping, modifying cascading tripping schemes, altering echo/permissive status etc., and these changes would be built right into the sequence of the outage plan as a matter of course.

More recently we have begun installing sectionalizing junctions with MOABs in our 230 kV circuits; in a few the required protection mods that accompany each circuit configuration may still have to be performed manually, in some instances the prot mods are driven by pallet switches connected to the switch's motor mechanism box, and in still other cases the SCADA system display and control screens have "radio buttons" that the transmission system operators/controllers must manipulate manually to alter the prot schemes. The variances in design are generally driven by the availability of the necessary comm paths more than anything else...

As Paulsey88 stated: "Tons of factors, tons of choices."

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[cuky2000]

Definitely 230 kV is considered a transmission voltage.

Most Independent System Operators (ISO's) consider a transmission voltage above 100 kV (>115 kV[sub]rms[/sub]).

Voltages in the range of 34.5 to 69 kV could be considered as a sub-transmission voltage and usually not monitored by the ISO.

[sub]NOTE: Should be noted that some deviation of this rule was granted by FERC to one utility in the East coast based in a grandfathering status for special conditions to qualify as a transmission asset for better return of the investment that may not be so attractive if considered a distribution project
[/sub]