ThePunisher
Electrical
- Nov 7, 2009
- 384
The design proposed to use 3 x ABB SSVT-350 (IPC) Voltage Station Transformers. A wye-neutral solidly grounded secondary winding is made by interconnecting the X2 terminals to ground and using the X1 terminals for the line conductors (see attached image). Each primary H1 terminals are connected to the 72 KV phases and H0 are connected to earth via ground rods.
My concerns are as follows:
1. There is no primary fuse protection. At 318 kVA capacity, the equivalent primary fault for a 3 phase or line-line fault at the secondary will be too small to be sensed by the power line remote overcurrent protection. Therefore I would insist for a primary fuse protection. Is my concern valid?
2. Upstream 72kV is a resistance grounded system. Since the SSVT primary H0 is solidly grounded, will this pose any risk to the upstream resistance grounded system? With the connection shown in the attachment, a ground fault at the secondary will be reflected at the primary. Will it be possible to re-connect the primary as a DELTA instead?
I was informed that there are already old installations in the facility that have the same configuration but I am still not that convinced they did the right thing.
Can anyone help me get the guidance I need?
I attached the SSVT Installation and Maintenance Guide on the second post
Thank you in Advance,
My concerns are as follows:
1. There is no primary fuse protection. At 318 kVA capacity, the equivalent primary fault for a 3 phase or line-line fault at the secondary will be too small to be sensed by the power line remote overcurrent protection. Therefore I would insist for a primary fuse protection. Is my concern valid?
2. Upstream 72kV is a resistance grounded system. Since the SSVT primary H0 is solidly grounded, will this pose any risk to the upstream resistance grounded system? With the connection shown in the attachment, a ground fault at the secondary will be reflected at the primary. Will it be possible to re-connect the primary as a DELTA instead?
I was informed that there are already old installations in the facility that have the same configuration but I am still not that convinced they did the right thing.
Can anyone help me get the guidance I need?
I attached the SSVT Installation and Maintenance Guide on the second post
Thank you in Advance,