138kv Cable in Tray

[rockman7892]

I’m looking at a project where customer is looking to install temp 138kv-34.5kv transformer in existing substation in order to repair existing transformer. Plan is to locate tramp transformer in separate location in yard and reconnect HV and MV bushings to existing buses work to minimize downtime.

One option that is being explored for temporary HV connection to transformer is 138kv cable ran in cable tray elevated a couple of feet off ground. Idea would be to build 2 temporary riser structures at each end of run to get cable up to transformer bushings and existing bus on other end.

Anyone ever use 138kv cable or similar in substations in cable tray? Anything that limits use in tray? Does cable need to be an oil filled cable like I’ve seen in underground transmission circuits?

 

[thermionic1]

I worked in a GIS station that took in 138kV UG cables. The cables came in in the basement and were on cable trays while they made their way to the GIS, about 100' or so before they went up on risers to the gear. This is a permanent configuration.

 

[JJ_Roy]

Nexans makes temporary HV cables that were used on a project I worked before. (

https://www.powerandcables.com/wp-c...gy-Transmission-Flowing-110kV-132kV-220kV.pdf

)

They were just laid on the ground and clamped together in a tri-foil configuration with special clamps [not zip ties or tape]. They were also barricaded just so no one stepped on or drove on them!!

You need to be concerned with the short circuit forces as this clip shows.(

https://www.youtube.com/watch?v=WPiH5X-Dz54

)

 

[bacon4life]

Lots of drawbacks to using oil filled cables rather than solid dielectric at 138 kV. For shorter distances like this EPR can be an alternative to XLPE.

 

[7anoter4]

Before 50 years I used oil filled cables [low pressure oil] of 110 kV. The pressuring equipment -pumps, conduit and meters were supervising required, also. I think there are today manufacturer for XLPE cable insulation as ABB, Siemens, Nexans and others.
A problem is the cable tray. You may consult tray manufacturer as B-Line- or other-in order to build the tray. I agree with JJ Roy -you need clamps in order to avoid cable damage in a short-circuit case.
See-for instance-CMP Cable Cleats or Id-Technik or others.