Anybody here a cathodic protection guru?

[Dsg319]

Had to install a dairyland SSD (solid state decoupler) on a section of pipeline entering a compressor station.

I know from instructions to have the negative terminal of the ssd on cathodic protected side of the pipe.(which is the pipeline and not the station)

But I was also told to connect the station bonding/grounding system to the negative side of the SSD as well.

Wouldn’t this connect the whole station to the cathodic protection which we are trying to prevent?

 

[quantum]

Typically the incoming pipeline to the compressor station will have isolating flanges that will block the DC current from the CP system on the pipeline, but also block any AC faults. To remedy, the SSD is installed inline from the station grid to the pipeline (cp protected) side of the flange. Once a certain voltage threshold is exceeded (typically +/- 2V), then then current can flow.

From my experience, the station grid is always connected to the + terminal. I just reviewed the installation details from two recent projects that utilized these devices and confirmed both engineering groups had us hook the station grid to the + terminal. The question is, can the terminals be swapped since each end must hook to a different terminal and they are asking you to hook the station grid to the negative side. I'm almost certain the answer is no, but you can give Dairyland a call to confirm.