15KV CABLE SHEATH GROUNDING

[ISMAEL VEGA]

[FONT=&quot]Hi all:[/FONT]
[FONT=&quot]I know there are several ways to ground the sheath on 15KVunderground systems. I know that many utilities use what is called singlepoint grounding. In this option, the cable sheaths are supposed to bejoined together and to ground in one end and on the other end, they're supposedto be connected to ground individually through a Sheath Voltage Limiter. In this option, a ground continuity conductor is needed to connect bothends. What I have saw is that utilities ask to solidly ground the sheatsat both ends and also to run the ground continuity conductor. This willcreate current loops that generates heat around the cable which limits thecapacity of the cable. Do utilities take this into account or does thiscurrent around the cable is negligible?[/FONT]
[FONT=&quot]I'll appreciate your explanation.[/FONT]
[FONT=&quot]Ismael[/FONT]

 

[Ragin Cajun]

The last one I dealt with the shield was grounded on only one end. The shield was not rated for fault current so there was a separate ground wire. You sure don't want a through fault frying the shields.

RC

 

[ISMAEL VEGA]

What about the ungrounded end?

 

[meternerd]

The way CA does it....All primary 12,470/7200 has the shield (neutral) connected to the system grounded primary neutral. At the padmount transformer, the shield is connected to a driven ground rod and the case of the transformer. The primary and secondary transformer winding neutrals are connected to the cases as well, but they are connected via a removable jumper. That is to allow the temporary removal of the grounds for testing. No separate ground conductors are installed with either primary or secondary.