Cable terminators or Bushings

[Humble2000]

Hi All,

I have seen pad mount transformers with different type of primary connections. Cable terminators or Bushings. What defines which type of system to use?
I also heared that the cable terminator is leaking?
Transformer is a 1500KVA 27.6KV/600V from Ferranti-Packard

 

[DTR2011]

Hi,

The difference in HV cable connections is generally based on safety concerns and switching. The cable terminations you are referring to are called "dead front". Utility workers have specialized hot stick tools which allows them to safely energize and deenergize the transformer.

The term dead front is derived from the fact that the actual cable to transformer connection is made inside the transformer tank. Theoretically, the cable termination is grounded, although I WOULD NEVER handle these connections without proper safety equipment. The benefits of the Dead Front Elbow connections is the easy of connecting and disconnecing to the HV terminals.

With bushing type connections, the HV is exposed, thus there are safety and clearance concerns. For a 27kV application, the cable to bushing connection should be taped or booted in order to minimize the effects of corona and improve clearance.

Hope this helps.