From reviewing some responses on other threads from forum user PRC and also reviewing some modeling data I have access to, it appears that the impedance between two secondary windings of a 3 winding transformer is roughly 0.95 the summation of the impedances between the primary and each of the...
I'm reviewing a project where there is a 270MVA 161/34.5kv transformer and no main circuit breaker on the 34.5kv bus. (I don't know of any circuit breaker for 34.5kv that is higher than 3000A which is a force air cooled switchgear breaker)
The 34.5kv bus has (8) 600A breakers. (7) of the...
We have a 325MW renewable site that was studied with a Y-g 345kv / Delta 34.5kv 350MVA two winding transformer but we are kicking around the idea of changing it to a three winding transformer to reduce the secondary current. If we kept the impedance the same between the primary and the two...
From reading the excerpt below from IEC 60076-8, I'm interpreting Z0 to be .85-0.9 the value of Z1. Is this a correct interpretation? I've recently seen utilities/ISOs requesting Z0 data on transformer during the interconnection studies and I can't seem to get a good understanding on this...
Has anyone ever seen a 345kv GIS underground connection where two sets of conductors are paralleled into the same position? I believe this can be done with AIS equipment based on my review of some substations in NYC but didn't know if it was possible with GIS. I have the question going into...
Anyone ever seen these before? I've only seen up to 275kV systems. What I'm trying to figure out is how far could a 345kv submarine cable go without charging current being a problem. *Edit: The system size is 1200MW
I've been looking into this a bit and it seems like the highest ampacity of readily available equipment you can get for 34.5kv is 3000A. I'm looking at a collector substation for a renewable projects where they are trying to produce 200MW and I'm wondering if there are alternative solutions to...
Sorry to start another one of these threads but I've gone through some of the old threads where Cuky2000 has responded and have a few questions. For a 345kv/34.5kv transformer is there a reasonable way to estimate the impedance and X/R? I've been looking at the Cuky2000 table named "Standard...
Does anyone have a recommendation for EMF study software besides using CYME? We are having a hard time justifying 30k for a software license and looking for some good alternatives. Thanks!
Hi everyone, I've been tasked with trying to figure out a way to extend an existing air insulated 345kV ring bus in a congested substation. There is not enough room to extend it with air insulated equipment so I'm left wondering if it could be done with exterior GIS equipment. Each end of the...
I'm looking a project where the owner has a switchboard lineup of |Dist-A|CT-Cab-A|Main-A|Tie|Main-B|CT-Cab-B|Dist-B|
Dist-A is rated at 3000A while all other bus sections, main breakers, and tie breakers are 4000A.
The switchboard already has a load side PV connection tapped into CT-Cab-A...
Hey everyone. I was looking at Pyrotenax MI cables earlier today and it appears that they offer an online voltage drop calculator on their website. It requires a quick signup to use. What I ended up doing was taking their online voltage drop calculator and back calculating the impedance of a...
Hi everyone, first post here. I recently changed jobs where I went from <600V to MV/HV. I reviewed the free resources on this site and was a little overwhelmed on where to start. Does anyone have a good recommendation on what to read first? I'm interested in learning more on relaying...
