Fuse vs Breaker substation cost

[Mbrooke]

How much cost is saved over using fuses and load break switches instead of breakers and their associated control equipment?

Scenario:

34.5kv-12kv substation with two 15MVA transformers. "H" arrangement. 3 34.5kv load break switches and 2 35kv fuse sets. 11 15kv load break switches and 8 15kv fuse sets. 8 outgoing 12kv feeders.

VS the same in breakers, isolators, VTs, ect.


40-60 year in service life.



Second question but on a similar note: Are on board tap changers available which are self power or only need a 120 volt source? Ie tap control in transformer compartment.

 

[bacon4life]

On your second question: I have not heard of substation transformer with integrated tap changers being self powered in the same way that standalone voltage regulators are self powered from an auxiliary winding. In that large of a transformer, I had assumed an auxiliary winding would add more cost that just buying a standalone station service transformer.

 

[Mbrooke]

But if I just ran 120 volt to it, I still could have the rest in the transformer? Or in the least do I still need buss VTs?