Coaxial with 250KV

[tryinghard]

I have a unique situation in a high voltage buss were the plan is to install RG59 coaxial cable from PDA devices to a remote test location. The PDA devices mount horizontally inside a 250kv buss way. These three devices each individually terminate on a phase (144kv) of 250kv 3ph, the signal then leaves on a coaxial cable. My concern is that the coaxial cable enters into the 250kv buss way for about 3' and it is not rated for high voltage. I would think these devices can be purchased to enable HV on one side and LV to the outside of the buss way but this is not the case.

I am not familiar with mixing low voltage signal cable in a high voltage area; it is AC so I would imagine there could be induction? Any other advise?

I notice 300-3(C)(2) but is there another section or code to pay attention to?

 

[jatrottpe]

Can you provide additional information on the PDA device.
Is it a protective relay device or sensor of some type?
Is it possible to get the device or sensor with Fiber Optic transmission capabilities as the High voltage would not effect the light transmission.

On our 230KV system we have CT's on the bus coming back to protective relays. All of our interfaces are in a control house at the high voltage bus.

If the instruments (pda) are designed for use on the high voltage system, the installation instructions should give some more information regarding acceptable wiring methods for the particular application.

API 552 has good information regarding recommended seperation distances for different types of signals to power cables.

 

[tryinghard]

...Is it a protective relay device or sensor of some type?

These are sensors

Is it possible to get the device or sensor with Fiber Optic transmission capabilities as the High voltage would not effect the light transmission...If the instruments (pda) are designed for use on the high voltage system, the installation instructions should give some more information regarding acceptable wiring methods for the particular application.

API 552 has good information regarding recommended seperation distances for different types of signals to power cables.

It would be best if these devices could accept fiber but they don't, they were actually installed by others and the signal side is with the HV bussing. I would think these could be purchased to allow the signal side to be external through the housing of the buss way.

Thanks for the reference I'll check it out.