Opinions on remote breaker operation for 34.5kV Switchgear

[rockman7892]

Interested to hear others opinions on the added cost and complexity of including remote breaker operation for operation of breakers on 34.5kV Switchgear. Obviously Arc Flash is a concern with Switchgear and moving worker away from switchgear when operating breaker increases safety and there are several ways to accomplish this (remote control panel/HMI, remote breaker operator, umbellical cord w/pendant, etc...)

Looking to weigh cost and complexity vs practicality. In my opinion if you are going to design safety controls for operation of a breaker you'll also need to include remote racking option for breaker to be racked remotely since most Arc Flash incidents happen during breaker racking.

Main 34.5kV bus will have buss differential so will provide mitigation of Incident Energy bus faults occurring on bus or load side of main breaker.

How have others approached this application with a balance between cost and safety design?

Thanks for the feedback.

 

[cranky108]

Use Arc-resistant switchgear. Use remote rackers, and chicken switches for remote switching. Or just switch with SCADA.
Another way is use a bus differential in the gear.
One can also use a switchable 50 element.

 

[DTR2011]

Make sure the floor is level. Make sure when the gear is installed that the gear is properly shimmed and level and the breaker cradle accepts the breaker properly. If you have remote racking and poorly leveled gear you will have a whole new set of challenges to deal with if something gets stuck half way in.

 

[unclebob]

What's upstream of that breaker? A switch , a transformer?

It should be easy to use the existant open/close electrical wiring and switch and move them away near the access door. Your breaker is electrically operated already?
Best is to rack-in, rack-out on a de-energized bus, where an upstream electrically-operated switch would help.

 

[rockman7892]

cranky108

Gear will have bus differential and therefore reduce IE levels. Would you put as much thought into trying to switch remotely with Buss Diff in place?

I don't have much experience with ArcFlash cals at this voltage level (and is outside of IEEE 1584 range) but I'd venture to guess at this voltage level and fault current aproximately 10kA the incident energy levels will be fairly low to begin with?

@unclebob - This is service entrance switchgear so upstream is a pole mounted switch so no real help with switching from upstream. Yes breakers are electrically operated.

 

[unclebob]

Ok, it's pretty easy to open the breaker with a remote electrical switch, then remove voltage with the pole switch and then un-rack the breaker. All this without much AF hazard.
The pole-switch is outside and if something happens, the blast will propagate in all directions, meaning it's going to dissipate fast. The blast will not be going directly at you as if it was happening in an enclosed box, with only one opening. Opening the breaker is the worst step, but since your using a remote switch, you should be well away from the breaker.