Do you mean why did we ground the neutral?
We normally have the grounded wye on the load side of the transformer so the grounded neutral gives us a good source of zero sequence current for tripping. We mainly serve residential and light commercial so we really aren't that familiar with heavy...
Thank you all, I've been reading all weekend and now see the issue. We are investigating a number of possibilities to compensate.
1. Supervise the ground trip with a directional element.
2. Float the high side neutral separate from ground.
I'm leaning towards floating the neutral for...
I've got a bit of a head scratcher on my hands. Last night I had a ground fault trip on a substation caused by a fault on an adjacent feeder. See Pic below for diagram.
The station that tripped for the ground fault is a medium voltage 14.4kV to 2.1kV station (Grounded Wye Primary / Delta...
So I've broached the idea of replacing the Delta with a high resistance grounded wye and we are going to consider it. I've been reading everything I can find on the subject however I have a few questions about converting the current Delta system to high resistance wye.
The current substation...
Waros,
The reason I fear changing the service to the customer is mainly fault current. My knowledge in this area is limited, but in general, it's my understanding is that delta 3 wire will have low fault current compared to grounded wye. Additionally the facility is a prison that was built in...
Magoo see answers below.
Let me ask some stupid questions so I don't waste your time.
What I understand from what you've said is the existing substation site has 25 kV on the high side. I assume this is a 4-wire multi-grounded neutral circuit or supply. Correct?
(That is correct.)
You...
Changing the customers facilities is not an option. Their system was designed to be fed by a delta when it was built in the 60's. The substation replacement is a project we've initiated to improve reliability and serviceability. For better or worse, we're stuck with the setup as is.
Tom
We are replacing our existing substation. It's a high value account so we decided to maintain an actual substation for service instead of just setting an auto transformer. We always build substations with regulation to ensure proper voltage.
Tom
I'm designing a small 25kV to 4.14kV distribution substation for a customer who needs a delta service. We don't typically supply a delta service so I do not have much experience with it. The station transformer will be a 5/7.5 MVA wye - delta and will be too small for an LTC on the tank. For...
I've had a question posed by one of my construction crews regarding a 115kV to 69kV station we are converting to all 115kV. All the bus work is designed to meet 115kV standards already, but the low side switch currently on site is a 115kV switch spaced at the 69kV separation of 6'. We are in the...
