I have been addressing for over 30 years but that seems to have been ignored by most other cathodic protection specialists.
If you are dealing with an intrinsically safe facility in the oil and gas industry there is always a requirement for an earthing ring that provides a common potential as a zero for all electrical equipment and telemetry .... including the cathodic protection transformer rectifiers.
This ring main is traditionally made of copper band about 1" wide and 1/8 thick simply buried around the perimeter fence and connected by spurs or thick copper cable to each piece of equipment.
The equipment and pipes that are earthed are made of a variety of metals thus forming bi-metalic or galvanic couplings submerged in a common electrolyte that in itself might differ from concrete to native soil.
This circuit must be defined in a drawing and then a schematic to show it as an integrated electronic circuit for analysis and to which data can be added together with historical information.
Electrical measurements should all be referred back to a single reference potential in a fixed position and then all voltages can be referred to a common zero. A copper copper-sulphate electrode can be used for this purpose as it has a known reaction potential.
You can then use a second copper copper sulphate electrode as a roving ground contact to obtain real voltages that will form a potential profile of the whole area. This can be displayed using three D graphic on Excel.
We then have to make sure that the pipelines and other buried plant are not acting as sacrificial anodes to the copper strip of the earthing system.
If you have gathered enough data you can calculate this using a spread sheet and I will tell you how to mitigate this problem if you are interested.
i ever had got problem for CP system at power plant, the pipeline contact with grounding system. so i gave a protection to pipeline and grounding system too.
You are correct as no one can separate the parts of what is effectively an integrated circuit. You should draw a schematic of the whole system using electrical symbols to make analysis clear.
I have been addressing for over 30 years but that seems to have been ignored by most other cathodic protection specialists.
ReplyDeleteIf you are dealing with an intrinsically safe facility in the oil and gas industry there is always a requirement for an earthing ring that provides a common potential as a zero for all electrical equipment and telemetry .... including the cathodic protection transformer rectifiers.
This ring main is traditionally made of copper band about 1" wide and 1/8 thick simply buried around the perimeter fence and connected by spurs or thick copper cable to each piece of equipment.
The equipment and pipes that are earthed are made of a variety of metals thus forming bi-metalic or galvanic couplings submerged in a common electrolyte that in itself might differ from concrete to native soil.
This circuit must be defined in a drawing and then a schematic to show it as an integrated electronic circuit for analysis and to which data can be added together with historical information.
Electrical measurements should all be referred back to a single reference potential in a fixed position and then all voltages can be referred to a common zero. A copper copper-sulphate electrode can be used for this purpose as it has a known reaction potential.
You can then use a second copper copper sulphate electrode as a roving ground contact to obtain real voltages that will form a potential profile of the whole area. This can be displayed using three D graphic on Excel.
We then have to make sure that the pipelines and other buried plant are not acting as sacrificial anodes to the copper strip of the earthing system.
If you have gathered enough data you can calculate this using a spread sheet and I will tell you how to mitigate this problem if you are interested.
i ever had got problem for CP system at power plant, the pipeline contact with grounding system.
ReplyDeleteso i gave a protection to pipeline and grounding system too.
am i right or false?
You are correct as no one can separate the parts of what is effectively an integrated circuit. You should draw a schematic of the whole system using electrical symbols to make analysis clear.
ReplyDelete