Pipeline Current Mapper PCM

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Pipeline Current MapperPCM
Radiodetection PCM
Electromagnetic AC attenuation and ACVG
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PCM Application
Radiodetection PCM

• PCM will find
• Coating defects (holidays)
• Shorts to other structures

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Transmitter
Radiodetection PCM

• High power output
• (150 Watts)
• Very low frequency to
• increase range
• reduce coupling to other services
• reduce field distortion

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Transmitter
Radiodetection PCM

• Powered from a transformer/rectifier site.
• From either rectified DC (20 50 V) or 110/240
  VAC.

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PCM Receiver
Radiodetection PCM

• Identifies signal from Transmitter
• Converts to Current
• Log to 400 records and download to PC
• Connect to GPS

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A-frame
Radiodetection PCM

• Pinpoint holidays
• Known as ACVG
• ...but SAME results as DCVG.

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Transmitter Connection
Radiodetection PCM

• Typical Transmitter to pipe connection
• Provides a perfect pipe connection point
• Anode provides perfect ground connection point

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Transmitter Connection
Radiodetection PCM

• Disconnect Rectifier
• Use same connections to connect the PCM
  transmitter

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Transmitter Connection
Radiodetection PCM

• Always direct connect
• Always use an independent ground
• - Anode Bed
• - Ground Stake
• - Across an insulator?
• Always have a map of the facility
• Never use another utility as the ground return.
• Never assume anything.

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Radiodetection PCM

• Locating Shorts
• - First signal loss may not be the short.
• - There may be more than one short.
• - There may be an unknown source.
• Locating Coating defects
• - Take readings at the same intervals.
• - Make sure PCM and boot is perpendicular to
  the pipe.
• - Hold unit steady and upright when reading
  current.
• You do not always have to connect closest to the
  suspected short or coating defect.
• More is not always better.

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Setting the Transmitter
Radiodetection PCM

• Three settings available
• ELF (498 Hz)
• ELF CD (8 Hz)
• LF (512 H z) CD
• Normal set to ELF CD

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Setting the Transmitter
Radiodetection PCM

• Set Current switch to desired current

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Taking Current Readings
Radiodetection PCM

• If ELF and arrows selected on Tx then select ELF
  on the RX
• Locate pipe in conventional way

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Taking Current Readings
Radiodetection PCM

• Hold the Receiver Steady on the ground and press
  the PCM Key.
• Current is displayed after 4 s

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Taking Current Readings
Radiodetection PCM

• Unit automatically performs steps
• narrow band signal processing measures 4 Hz
  signal (magnetometer)
• proceed to calculate depth (twin aerials)
• calculate current
• determine CD (using 4 Hz 8 Hz shift).

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Current Direction
Radiodetection PCM

• Indicates which direction the Current is flowing
• Aids fault analysis

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Radiodetection PCM
Methodology using PCM for Current Surveys

• Use an independent ground and try to mimic your
  CP circuit when possible
• Make sure rectifiers are not influencing the
  signal (turn off AND disconnect if necessary)
• Isolate your circuit whenever possible
  (disconnect bonds for better surveys)
• Take readings at equal distances and record your
  distances
• Every 50 feet is a good standard (others can be
  used dependant on location)
• Use it as a macro tool and depth of cover tool
  (use A-frame for micro)
• Look for anomalies with more than a 5 change
  normally
• Make sure unit is upright and perpendicular to
  the pipe
• Use the peak mode. Check peak and null readings
  and verify depth when readings are suspect.
• Take multiple readings in one location if you
  suspect the accuracy.
• Know what is in the area of your pipe and what it
  is connected to it

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Datalogging
Radiodetection PCM

• 400 records can be stored.
• Records can be
• reviewed on PCM
• downloaded to a PC
• Records can be viewed on Excel

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Datalogging
Radiodetection PCM
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A-frame
Radiodetection PCM
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A-frame
Radiodetection PCM
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Radiodetection PCM
PCM with A-frame for Alternating Current Voltage
Gradient Surveys

• Used as a micro and a macro survey tool
• Can be used in various soil conditions but
  ground contact of the probes will affect the
  readings
• Rectifiers generally do not influence the ACVG
  survey
• In areas of high interference or where current
  survey does not give you answers, ACVG can still
  be used with more success
• Know what is in the area of your pipe and what
  is connected to it
• Larger holidays can mask smaller ones until the
  larger holidays have been repaired
• PCM displays A-frame readings in db or decibels.
  Remember every 10 db higher is twice as large
• Metal to dirt contact and soil resistance (not
  necessarily size of holiday) is what affects the
  db readings

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ACVG Methodology
Radiodetection PCM

• Use an independent ground and try to mimic your
  CP circuit when possible
• Take readings parallel and along the pipe. When
  you see an arrow reversal go perpendicular to the
  pipe and make sure arrow reverses over pipe
• You do not have to be right on top of the pipe
  when surveying
• On concrete and asphalt use wet sponges or rags
  on the probes or wet the ground around the
  probes.
• Take readings at equal distances usually about
  every two to three steps
• Use the largest db reading seen around the
  anomaly for you records
• Record all faults seen with db readings and
  footages or GPS coordinates.
• Once done, anomalies can generally be
  categorized into 4 areas
• 80db 100db large
• 65db 80db medium
• 50db 65db small
• 50db and below very small
• LOCAL CONDITIONS DETERMINE WHAT IS A DIG!

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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM
Graphing in Excel and Data Interpretation
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Radiodetection PCM