Pipeline Current Mapper PCM+

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1 Pipeline Current Mapper PCM+ Radiodetection PCM

description

Radiodetection PCM. Pipeline Current Mapper PCM+. Radiodetection PCM. The PCM can…. Find contacts with other structures Evaluate Pipe Coating for defects Perform periodic Pipeline surveys Find defective Insulation joints. Radiodetection PCM. What is different about PCM. - PowerPoint PPT Presentation

Transcript of Pipeline Current Mapper PCM+

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Pipeline Current MapperPCM+

Radiodetection PCM

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The PCM can….

• Find contacts with other structures

• Evaluate Pipe Coating for defects

• Perform periodic Pipeline surveys

• Find defective Insulation joints

Radiodetection PCM

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What is different about PCM• High output power Transmitter

• Low Frequency signal

• Current Direction of applied signal

• Data logging of current measurements

• A Frame pinpointing of coating holidays

Radiodetection PCM

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Benefits of low frequency

Radiodetection PCM

testpoint

AC Tx

signalstrength(dBmA)

distance

DC

4Hz

1KHz

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Benefits of low frequency

Radiodetection PCM

1A (1KHz)

400mA

600m

A200mA

400m

A

1A (4Hz)

40mA

960m

A900mA

60m

Afault

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The Transmitter utilises..

• High output power (150W)

• Very low frequency

• This helps to…. increase range reduce coupling to other

services reduce field distortion

Radiodetection PCM

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The Transmitter

• Can be powered from… 110/240Vac The D.C output of a

rectifier (20 to 50vD.C) External Automotive

batteries (24v to 48V)

Radiodetection PCM

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PCM Receiver provides..• Pipe location and

depth

• Current measurement of survey current

• Stores up to 999 readings for download to a PC or PDA

Radiodetection PCM

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Transmitter connection• Typical rectifier

installation.

• Provides a perfect pipe connection point

• Anode provides perfect ground connection point

Radiodetection PCM

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Transmitter Connection

• Disconnect the rectifier output from both pipe and Anode

• Connect the PCM transmitter in place of the rectifier

Radiodetection PCM

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Setting the Transmitter

• Three output settings

4Hz and 98Hz

4Hz, 8Hz and 98Hz

4Hz, 8Hz and 512Hz

Radiodetection PCM

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Setting the Transmitter

• Set Current switch to desired current

• The PCM transmitter is a constant current source, this ensures stable survey readings.

Radiodetection PCM

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Taking current reading

• Ensure both PCM receiver is set to the same frequency as the Transmitter

• Pinpoint the pipe in the peak Mode

Radiodetection PCM

100%95%

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Taking Current Readings• Hold the Receiver

Steady on the ground, press and hold the PCM Key.

• Current is displayed after approximately 3 seconds

Radiodetection PCM

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PCM current v Line Drops

Radiodetection PCM

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34

56

78

910

LOCATION Nr

000001111

AMPS

LINEAR COMPARISONS

Data obtained during comparative tests on site

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Current Direction• This tells you in which direction the

Current is flowing – Aids fault analysis

Radiodetection PCM

Transmitter

short

target line

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Datalogging

• 999 readings can be stored• Stored readings can be

reviewed on PCM+ or downloaded to PC

• Downloaded files are in text format and can be displayed using Excel or 123 speadsheets

Radiodetection PCM

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Pinpointing Coating Defects

• For accurate coating defect location use the A Frame

Radiodetection PCM

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Finding Coating Defects

Radiodetection PCM

TransmitterA-Frame

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Case Histories

Radiodetection PCM

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Radiodetection PCM

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Defects found by PCMCut away ready for repair

Radiodetection PCM

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Close up view of cutaway showing area of metal loss

Radiodetection PCM

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Cables in contact with pipe

Radiodetection PCM

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Sheet pile in contact with pipe

Radiodetection PCM

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Current Attenuation GraphActual PCM Results

3 steps are different looking in mA but nearly identical in dB

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AC Voltage Gradient• Can be part of Current tools• Becoming very popular• Extreme sensitivity• Rejection of interference• Very accurate location of faults

– typically better then 6"

• Sometimes part of Current Attenuation equipment• This method deserves to be considered as a solid

tool for integrity and the ECDA process.

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ACVG in Operation• Both signal

strength and direction arrows lead user to holiday.

• Fault value is proportional to holiday size and

soil resistivity.

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Pool of PotentialIs AC, but at any instant in time, there is a direction.Is AC, but at any instant in time, there is a direction.

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ACVG Receiver Theory

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ACVG Tuning

• Older systems used a simple DMM– Does not tune to any one frequency– 60 Hz, cable earth faults, telecom noise Rx’d

• Very tight tuning in the signal generator and receiver effectively increases sensitivity as it ignores current from other sources– SNR improves

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• In this case the next fault was quite close (20-30m) which is why the left side of graph climbs quickly.

• Other cases may show 100s of meters of signal at 30 and under..

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Dig Pictures