rcdallas
07-11-2011, 07:53 PM
I'm still not clear on this, and I'll show why...(this comes from two different threads)
A 3 pot grounding bank is is simply a wye delta bank with the wye grounded on the high side it is used on delta systems to provide that "neutral" connections for the concentric it is also used in ug that works with SWER. As to why it is used you answered your own question sir.
Above your saying to have the wye grounded on the high side, and the purpose of it is so that if you have a underground primary fault it'll blow a fuse.
Don't know what SWER means.
The big problem with delta primaries is that they have difficulty sencing phase to ground faults. Lets be honest.... in our line of work,,,, most faults are phase to ground. All the relays in the world wont pick up, and open a phase of delta primary laying in the dirt:( One way around this is two install a grounding bank as close as possible to the station breaker. Nothing more than a three phase bank with one leg of the secondary connected to ground. This gives the relay some sort of relationship to ground and allows it to trip the breaker during a fault.
Then here topgroove is saying to ground a leg of the secondary
See why it's as clear as mud to me right now?
Leif, I can see your talking about for going into a dip pole, and topgroove is talking about using one for relay use.
Either way I'm not sure if it's the same principal just using it for two different applications or what. I'm still not clear as to how your grounding either one of them.
I understand the concept of utilizing a grounding bank, top spelled it out; most of our faults are phase to ground.
Ya'll just running a jumper to the pole ground? Anyone got any diagrams? Both things written above are conflicting, 1 says ground high side, other talks secondary.
Ya'll just use 3 of the smallest kva transformers? Is there ever a reason to use large kva transformers (fault current closer to the sub, etc...)
For the record I've tried pickin some brains on this very thing before with someone very respectable on here over the phone and he didn't know too much about grounding banks...just enough to make me ask more.
...?
A 3 pot grounding bank is is simply a wye delta bank with the wye grounded on the high side it is used on delta systems to provide that "neutral" connections for the concentric it is also used in ug that works with SWER. As to why it is used you answered your own question sir.
Above your saying to have the wye grounded on the high side, and the purpose of it is so that if you have a underground primary fault it'll blow a fuse.
Don't know what SWER means.
The big problem with delta primaries is that they have difficulty sencing phase to ground faults. Lets be honest.... in our line of work,,,, most faults are phase to ground. All the relays in the world wont pick up, and open a phase of delta primary laying in the dirt:( One way around this is two install a grounding bank as close as possible to the station breaker. Nothing more than a three phase bank with one leg of the secondary connected to ground. This gives the relay some sort of relationship to ground and allows it to trip the breaker during a fault.
Then here topgroove is saying to ground a leg of the secondary
See why it's as clear as mud to me right now?
Leif, I can see your talking about for going into a dip pole, and topgroove is talking about using one for relay use.
Either way I'm not sure if it's the same principal just using it for two different applications or what. I'm still not clear as to how your grounding either one of them.
I understand the concept of utilizing a grounding bank, top spelled it out; most of our faults are phase to ground.
Ya'll just running a jumper to the pole ground? Anyone got any diagrams? Both things written above are conflicting, 1 says ground high side, other talks secondary.
Ya'll just use 3 of the smallest kva transformers? Is there ever a reason to use large kva transformers (fault current closer to the sub, etc...)
For the record I've tried pickin some brains on this very thing before with someone very respectable on here over the phone and he didn't know too much about grounding banks...just enough to make me ask more.
...?