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| Do you use remote operation? i.e. racking/switching? https://brainfiller.com/arcflashforum/viewtopic.php?f=33&t=4440 |
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| Author: | Jim Phillips (brainfiller) [ Sun Sep 17, 2017 11:17 am ] |
| Post subject: | Do you use remote operation? i.e. racking/switching? |
Does your company / client(s) use any remote operation of devices i.e. racking/switching Yes No |
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| Author: | bbaumer [ Mon Sep 18, 2017 3:56 am ] |
| Post subject: | Re: Do you use remote operation? i.e. racking/switching? |
Yes, we do. In our substations we have 3 separate Pederson/Eaton switchgear houses all with remote switching buttons to open/close. The buttons are inside the gear house but off to the side very far away from the gear. We also have a remote racking motor with a long cord a man can plug into/hang on the front of the breaker cubicle and then stand far away, even outside of the gear house if he chooses to while racking in/out. Two of the gear houses are 12,470 set up for main-tie-main with 8 feeder breakers. One gear house if 4,160V, also main-tie-main with 8 feeder breakers. |
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| Author: | Gary B [ Mon Sep 18, 2017 8:19 am ] |
| Post subject: | Re: Do you use remote operation? i.e. racking/switching? |
Using a portable remote racking device was problematic in getting things lined up properly and then having confidence the breaker was properly engaging in 13.8kV gear, with little or no feedback on tork required (there were indicating lights provided for tork feedback, but there also was too much potential for confusion on this). The effort was abandoned and racking is accomplished using full arc flash PPE. Remote controls were added to one substation, and this too was problematic with the large amount of inter cabinet wiring not fitting well into the remote panel, and providing potential problems or exposure to wiring defects. It is working now but remains to be determined if this will be attempted on future substations, perhaps with better marshaling of control conductors. |
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| Author: | PaulEngr [ Mon Sep 18, 2017 10:07 pm ] |
| Post subject: | Re: Do you use remote operation? i.e. racking/switching? |
Missed the remote "racking" vs. "switching". I would have answered yes if I noticed the switching reference. They are two entirely different subjects. Remote open (ie, trip) is really simple to do. It is basically "for free" with microprocessor relays (Multilins, SEL's, Basler, even URC AC-Pro's). A lot of operations have it but often don't use it. Even old electromechanical relays often supported "mimic" panels which is really just yet another shunt trip in parallel. However with the traditional breaker mechanism, remote close is a horse of an entirely different color. A trip coil is in a lot of ways a very simple latch/hair trigger that requires a small amount of energy to activate. The charging function on the other hand is the mechanism that stores that energy. Most older breakers use a motor for this. It adds considerable cost to the breaker so it wasn't often done in industrial plants. I've really only seen it commonly used in fairly complicated automatic transfer and load shed schemes, especially with ties involved. Utilities with remote control substations also use these extensively. However the new kid on the block is the magnetic actuator. This is a completely different approach to breaker operation. It uses a rare earth magnet, two coils, and 2-3 springs. Theoretically it actually only needs one moving part (the magnet) and no springs but that doesn't seem to be the prevalent design which uses two springs to sort of balance and control movement, and the ABB version also has a teeter-totter that adds considerably more moving parts. With this design though the big thing is that tripping and closing are basically almost identical operations so implementation of tripping and closing is again almost "for free", so breakers using this mechanism come with both trip and close electronic signals. As to remote racking...it's a nice concept but I haven't seen it used very often partly because implementation is very problematic. I have however seen a lot of promoting of the idea of getting away from racking entirely and this definitely has it's merits. Bolt on equipment is a lot more reliable and the number of times where racking equipment off allows for repairs is really small (think panelboard requiring little to no maintenance vs. open cast frame ANSI breakers requiring frequent maintenance). And the number of conditions where the online replacement practice can be used doesn't make up for the loss in reliability. In other words draw out gear is attractive because effectively you CAN maintain it but panelboards and switchboards are attractive because with switchgear you HAVE to maintain it. And by those terms i don't mean that bolt in gear doesn't need maintenance and similarly that many sites haven't gotten away with not maintaining their switchgear (that's a little debatable) but the concept holds true. |
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