Thanks. I suppose the best way to visualize this by drawing the symmetrical components for a fault on 24.5kV system and see that the fault current has path through zero transformer in zero sequence network regardless of generator is connected or not. At least I think this is the way I explained...
Looking at an application where a new 24.9kV - 12.47kV transformer is being added for interconnection of wind farm to utility 24.9kV distribution line. Transformer is 15MVA and will have delta side facing generation (with grounding transformer on that side) and the wye side facing 24.9kV...
To follow this simple example lets say receiving system in C is pulling load at a .85 lagging pf. Are you saying that the voltage between A & B could be adjusted to that B had a higher voltage than A to the extent necessary to offset lagging reactive power from A and thus make unity PF on B...
Thanks for all the input, this has been an interesting read and learning experience.
To add to my earlier example here in FL, given that FPL seems to be the transmission owner/operator in most of the state i'm assuming they'd be the one wheeling the power in example of power purchase...
So it seems like cross bonding is essentially bonding at both ends which results in no build up voltage and also does not cause reduced cable ampacity due to circulating currents with shield bonded at both ends.
When cables are not sectionalized for cross bonding and are only a single run...
Thanks for the responses, very helpful. No what I understand the figure and reading through the standard it appears that the standard only addresses single point bonding and cross bonding but not an application where the shield is simply bonded to ground at the end of each cable run.
It...
Thanks for reply. I was able to get my hands on IEEE Std 575 which has a lot of good info.
One thing I don't quite follow in the standard is how they define multiple single point grounding. I'm used to terminology of "grounded at one end" or "grounded at both ends" when it comes to discussion...
This is a question which I've wondered about for quite some time and although I think the answer comes down to commercial agreements as opposed to flow of electrons I was curious to hear from some of the experts here.
As an example I've heard of scenarios where a new generation plant or...
One other observation I had on several large scale renewable projects (BESS, Wind) is that on the 34.5kV collector system feeders from HV substation out Wind/BESS modules had both a concentric neutral as well as separate equipment ground conductor (typically #2AWG).
Have others found that to...
After looking into this a bit further I believe I've found some better understanding to my above questions.
From what I can see, anything inside of a HV substation yard that has a ground grid utilizes the ground grid for ground fault current between fault location and source in substation (or...
I know that the NEC requires additional Equipment Ground Conductors (ECG's) to be run with any feeders between equipment and Supply Side Bonding Conductors (SSBJ) to be run between transformers of separately derived system and downstream equipment.
My question is in a HV substation environment...
I’m looking at a project where customer is looking to install temp 138kv-34.5kv transformer in existing substation in order to repair existing transformer. Plan is to locate tramp transformer in separate location in yard and reconnect HV and MV bushings to existing buses work to minimize...
I've never quite gotten my head around the concept of "GPR". Is GPR the voltage difference between equipment in substation and local earth, equipment to remote earth, or difference between local and remote earth.
If someone has a basic example, they can share to help solidify I'm sure that will...
I know that for applying a PT on a 4.16kV impedance grounded system (non-rigidly grounded)the PT needs to be a 2400/4160Y PT as opposed to a 2400/4160GY PT due to the fact that the neutral bushing needs to be a fully rated bushing for when neutral floats to line voltage during certain fault...
@wcaseyharman
For detection of utility side faults would the PT's for volage detection need to be on the utility side or could they be on the gen side of transformer (delta side)? Would PT's need to be connected in wye-gnd/wye-gnd config or would this be wye-gnd/broken delta for use with 59N...
In looking at this application a bit further I'm not certain that I need the new 24.7kV high side recloser that I have shown on one-line. In looking at most distributed generation applications connected to utility distribution I found that there is only a breaker on low side (DG side) of...
What about a situation when the existing recloser detects loss of utility, utility fault, or collector circuit fault and opens thus leaving the generation collector circuit ungrounded until wind turbines are shut down. Assuming that each turbine has a step-up transformer to 12kV with delta side...
For some reason SLD didn't attach to previous post so trying again here. https://files.engineering.com/getfile.aspx?folder=a6db0ec2-587f-48b5-9a28-4039659e4351&file=One-Line.pdf
Attached is SLD. The black is what is currently there today and the red is what is being added for transformation to 25.9kV. I Appreciate any feedback.
@protoslash thanks for your explanation on purpose of grounding transformer, that makes sense now.
