Larry,
Can't say that I have dealt with one of these systems lately (within the last 2-3 years), but between the mid 1980's and Y2K (year 2000), I dealt with a few here and there.
The more "Common" System in the "Old School Days" I ran across, was the Ungrounded 3 Wire Delta.
I have some Schematics + data in the Technical Reference section, which may be of assistance to you + the E.C.
Check out the
Corner Grounded 3Ø 3 Wire Delta Topic for some assistance regarding the Corner Grounded Delta setup.
Scott35
https://www.electrical-contractor.net/ubb/Forum15/HTML/000078.html (same as link text above)
