1 / 127

Formal PCM Training Program “The ABC to XYZ of PCM”

Formal PCM Training Program “The ABC to XYZ of PCM”. (And some ACCA and ACVG too) Radiodetection Developed/Presented by Gord Parker, C.E.T. Scope. Detailed course: basics to full comprehension Enough CP, GPS, NACE, ECDA to understand how PCM fits in amongst them.

futrell
Télécharger la présentation

Formal PCM Training Program “The ABC to XYZ of PCM”

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Formal PCM Training Program“The ABC to XYZ of PCM” (And some ACCA and ACVG too) Radiodetection Developed/Presented by Gord Parker, C.E.T.

  2. Scope • Detailed course: basics to full comprehension • Enough CP, GPS, NACE, ECDA to understand how PCM fits in amongst them. • Modeled after Dave Wulff's popular seminars • But with hands-on • Not marketed as generic, ALL PCM • Exam ?

  3. Time / Costs • 2 full days • Travel to several cities (5 CAN, 15 US?) • 500 / head? • GTI’s course U$1995 !!! • Logistics: venue, access to airport, hotel, meals, hands-on site, PPE • Need several Demo kits available • Need GPS eqmt.

  4. Itinerary • CP review • minimum detail, these are mainly CP pros • only to show how PCM fits in • NACE • ECDA Practice • ACCA • ACVG • DCVG (& strengths over) • Pearson (& strengths over)

  5. Itinerary 2 • Field Work • Interpretation • GPS Integration • PODS • SCM Introduction

  6. CP review • minimum detail, these are mainly CP pros • only to show how PCM fits in

  7. CP Theory • Buried steel  pipelines corrode. • How to protect ? • Coatings • ... but are never perfect • 1 Ampere for 1 year takes 1 kg of metal. • Reverse the electrochemical process  Apply a CP current !! • Rectifier, or ... • Sacrificial anodes (no AC required, no CPS).

  8. Cathodic Protection - CP • Keeping a pipe more negative then the dirt around it prevents most corrosion • Simple as a 12v battery charger • + (positive) to the Anode bed • - (negative) to the Pipe(s) • So CP reverses the current flow, adding enough current to zero out the metal loss.

  9. Typical Rectifier System Groundbed (anode) Current through the dirt. + ve cable (DC output) Rectifier AC supply minimum 110v - ve cable Pipe = Cathode = DC current

  10. Typical Rectifier • Wasps • 110 v plug • On/Off Breaker • - cable to pipe • + GroundBed NOTE !!! There are hazardous voltages present inside rectifiers. Accidents happen, an Alberta CP tech with years of experience was killed (electrocuted) just two years ago. Only qualified technicians (formal electrical and safety training) may open and work inside a rectifier. This is shown for reference and so you may assist a qualified electrician connect your transmitter inside a rectifier. Pictures compliments of: http://www.irtrectifier.com/

  11. Rectifier Connection Pull 1 or both wires off & connect transmitter. Red or white wire to Structure terminal. NOTE !!! There are hazardous voltages present inside rectifiers. Accidents happen, an Alberta CP tech with years of experience was killed (electrocuted) just two years ago. Only qualified technicians (formal electrical and safety training) may open and work inside a rectifier. This is shown for reference and so you may assist a qualified electrician connect your transmitter inside a rectifier.

  12. Junction Box / Multiple Output • You may have to disconnect and locate each circuit individually • Remember which wire went where • Or use clamp (explanation coming up) • Junction boxes elsewhere can affect you • Gets your locate current onto other pipes • May need to have them disconnected

  13. Sacrificial Anodes • A.K.A. ‘Mags’ (Magnesium) or ‘Zincs’ • Also supply current to reduce corrosion • By chemical action, not from 110v • NO CPS mode signal (perfect DC) • If they are at your Tx connection, they will suck LOTS of locate current to earth • Thus much less on your target pipe • May need to disconnect or use clamp

  14. Test Posts • A test post is always so techs can connect eqmt. to buried pipes • 4 typical reasons • Just a simple pipe • 2 wires (1 for backup) • Across an insulation joint • 1 or 2 wires to each pipe • Mg/Zn Anode • NO signal? This’d be why • Multiple pipes • Tx to each wire individ’ly & observe signal dir.

  15. Here’s what it does to locate Current • Locate tone goes everywhere CP does. • You may need to remove jumpers • Remember where they all went. • Sometimes may be a ‘map’ inside lid.

  16. Typical Header • Current may or may not go everywhere • Depends if the flanges are electrically insulated to stop current.

  17. Flange Insulation Kit One of these on EVERY bolt. Extends through to an insulating washer under nuts.

  18. Insulated Flanges • To prevent current from flowing • Washers installed on ALL bolts • Make sure transmitter leads are on correct ‘side’ of insulation • No wires shorting Usually only on one side of flange Make sure is on ALL bolts

  19. Non-Insulated Flange • One or more bolts missing washers • Doesn’t matter where leads are clipped • Clips light up everything • If part of a header, CLAMP puts the most signal ONLY on target

  20. Insulated or Not ? Both washers on nuts & sleeves on bolts are present. But are they on all 16?

  21. Insulated Fitting - Wellhead • A wellhead will often have an insulated fitting • Use clips, • ground to well side - 1000’ ground rod !! • If it isn’t insulated 90% of locate current goes down casing. • Use Clamp, good ground means good current

  22. Insulated Fittings Elsewhere • Will affect your locates • No current will flow towards an ‘open circuit’ • What if you have to locate in Blue area ?

  23. Insulated Fittings Elsewhere • Simple Solution • Move transmitter to get signal in these areas • MUCH better fix than using a bigger hammer

  24. Casings • Misunderstood. • A casing is a larger pipe around the important pipe designed to take the brunt of mechanical loading from the road/RR. • The vent pipe is connected to the outer casing ONLY, it is usually NOT connected to the inner pipe. • Thus, connecting to vent does no good.

  25. Casing Cut-away Picture • Target pipe inside casing, supported by insulating ‘donuts’.

  26. Typical Casing If you’re lucky there will be a test post for the casing. Some wire(s) will go to the target pipe and wire(s) will go to the casing. Connect transmitter to each individually and observe.

  27. Another Casing

  28. Which frequency should I use ? Extremely Low Frequency ELF (98Hz) Very Long Range Won’t chase towards insulator Little "Spillage“ Good IDent 4 Hz (Near DC) Used in all PCM output modes Low Frequency LF (512 Hz.) Shorter Range More "Spillage“ Gets closest to insulators/stubs 8 Hz (↕) optional Provides F/B arrows Used in loops with ACCA And with ACVG and a-frame

  29. Which Frequency ? High frequency signal quickly escapes from target line and may return on an adjacent line. Lines in close proximity will readily accept signal. This can lead to field distortion and poor locate information.

  30. Which Frequency ? Higher frequency = shorter range (greater capacitive signal loss to ground). This frequency is better for induction onto small or short length conductors, or towards ends-of-mains.

  31. Which Frequency ? Low frequency = long range (minimum capacitance signal loss to ground). This frequency is better for connection and locating longer metal pipes or cables.

  32. Which Frequency ? High frequency may locate T’s or shorter stubs which are not grounded at the termination point. BUT range on main line is reduced and may induce (ghost) onto crossing services.

  33. Which Frequency ? Low frequency tends to keep to main line, does not induce onto crossing lines and bypasses T’s which are not grounded.

  34. NACE International • Started in 1943 with 11 engineers as the National Association of Corrosion Engineers • Now 15,000 members in 93 countries and a name reflecting their world wide presence. • www.nace.org • Covers ALL aspects of corrosion • Members write standards, offer courses, lobby government, publish findings, more.

  35. ECDA Practice The Pipeline Safety Improvement Act of 2002 • US signed into law on December 17, 2002 • Applies to nat. gas xmission (dist. coming) • Must ID "high consequence areas (HCA)" • conduct risk analyses of these areas • perform baseline integrity assessments of each pipeline segment • inspect the entire pipeline system according to a prescribed schedule and using prescribed methods

  36. Other provisions of the law include The Pipeline Safety Improvement Act of 2002 • Participation in one-call notification • Increased penalties • “Whistle-blower" protection • Operator Qualification for employees • Government mapping of the p/l system • Other Housekeeping Stuff

  37. BUT… • Some pipes have serious limitations to inspection • Not Pigable (small valves/openings, 90° fittings) • No redundant loops – had to stay in service • Hence, no hydro-testing either • Best Quote I’ve heard this year… “Congress is a little leery of engineering because you can’t barter, you can’t negotiate with it.”

  38. Direct Assessment • Direct Assessment came along • It seems to have been accepted & implemented fast • There are 3 types of DA (for 3 types of threats) • External Corrosion (ECDA) • Internal Corrosion (ICDA) • Stress Corrosion Cracking (SCCDA) • ECDA is the most mature of them. • RP0502 – 2002 is the defining NACE doc.

  39. ECDA is a 4 Step Process • Pre-assessment • Most important step • Indirect Inspections • Above-ground Tools • Direct Examinations • Verification Digs AND Mitigation • Post-assessment • Define Reassessment Period (US: 7 yr typ. max) • Assess Overall Effectiveness

  40. Important Definitions • ECDA Region – Section(s) of pipeline with similar physical characteristics and history in which the same indirect inspection tools are used • Segment – A portion of pipeline assessed using ECDA. Consists of one or more regions. • HCA – High Consequence Area (higher population density, limited mobility, gathering places, etc.)

  41. General Notes • There is some flexibility to chose suitable processes • Continuous Improvement Process • Compare successive applications to gauge effectiveness • Primary Purpose – Preventing future problems • RP0502 is for onshore, buried, ferrous pipelines • Stand-alone or compliment other tests (ILI, hydro) • Has limitations (like all assessments), use appropriately • Use under the direction of ‘competent persons’

  42. Step 1 – Pre-Assessment • Determine if ECDA is feasible and applicable • Collect ‘Soft’ Data (both current & historic) • Construction, Operating, Maintenance, CP survey, Adjacent Land Use (and changes to), and more • This is a big part – spend the time planning • Define Regions • Especially HCA • Select Indirect Tools appropriate for those regions

  43. Include each of these Data Elements • Pipe-Related • mat’l, diam.,thickness, year, seam type, coating • Construction Related • year, route, aerial photos, construction practices, valves, depth of cover, more • Soils/Environmental • soil, drainage, topography, use, frozen, wet • Corrosion Control • CP system, location, stray current, history, evaluation, coating • Operational Data • temperature, stress, fluctuations, excavations, accidents

  44. Which tools are applicable • Close-Interval Survey (CIS) • AC Voltage Gradient • DC Voltage Gradient • Pearson • Electromagnetic • AC Current Attenuation Surveys • Stray Current analysis • Different regions may require different tools

  45. Step 2 – Indirect Inspections • Identify and Define the severity of coating faults, other anomalies, and areas where corrosion may be • Requires at least two aboveground tools over the entire length of region • Then align & compare the data • More than 2 may be required

  46. Gathering Indirect Data • Quite expensive • Do it right the first time • Plan for traffic, access, problems, surveying • Conduct & Analyze with accp’d Industry Practices • Reading spacing must be suitably fine • Different tool (passes) done close in time as well • Precise Geographic References (GPS)

  47. Gathering Indirect Data • Compare Results • If indirect tool results vary greatly, reexamine (directly if need be) • Compare the results with Pre-Assessment

  48. Step 3 – Direct Examinations • Purpose: To determine which indirect indications are most severe and collect data to assess corrosion • Requires pipe surface exposure & testing • At least one dig is always required

  49. Steps Included • Prioritization of Indications • Excavations & Data Collection • Measurements of Coating Damage & Corrosion • Remaining Strength Calculations • Root Cause Analysis • Process Evaluation

  50. Prioritization (3) • Immediate Action Required • Ongoing corrosion likely • Multiple Severe Indications • Unresolved Discrepancies from Indirect Exams • Scheduled Action Required • Severe indications NOT in area of other severe • Suitable for Monitoring • Inactive or little likelihood of ongoing/prior corrosion

More Related