Download REMOTE MONITORING of CP FOR PIPELINES AND TANKS

NACE International
Eastern Regional Conference
REMOTE MONITORING of CP
FOR PIPELINES AND TANKS
Presented by James B. Bushman, P.E.
Bushman & Associates, Inc.
Corrosion Consultants – Medina, OH
44256
www.bushman.cc
at the
2009 NACE International
Eastern Regional Conference
REMOTE MONITORING CP FOR PIPELINES & TANKS
 Why
use remote monitoring?
– Save money
– More accuracy
– More data
– Obtain readings we can’t easily take
– Increased frequency of readings
– Spend our time problem solving rather
than meter reading
REMOTE MONITORING CP FOR PIPELINES & TANKS
What do we want to read?
•Rectifier DC Voltage and Amperage
•Pipeline Potential
•Test Station and/or Coupon Readings
•Critical Bonds
REMOTE MONITORING CP FOR PIPELINES & TANKS
Rectifier Voltage:
00.0 VDC
Rectifier Amperage:
Across shunt resistor
(preferably 1 Ampere per Millivolt)
Measure mVs to 0.1 mV
Structure Potential
With permanent (??) reference electrode
On & Instant Off
Interrupt Capable (with GPS Sync)
REMOTE MONITORING CP FOR PIPELINES & TANKS
Rectifier AC Power:
XXX volts
Rectifier Temperature:
Thermocouple measured in mV
Read how often vs. report how
often?
Any Other Readings??
REMOTE MONITORING CP FOR PIPELINES & TANKS
Resolution:
•Digital Store and Transmit Resolution – Uses A to D
converter – generally uses XXXX bit resolution
– 12 bit resolution = 2^12 = 4096 segments over range
– 16 bit resolution = 2^16 = 65,536 segments over
range = 0 to 4 volt range can measure to 0. 1 mV
– +/- versus 0 to X
– Using 16 bit resolution and +/- 4 Volt range, can only
resolve to 1 mV
–If I instead use 20 bit A to D converter,
1,048,576 segments over range,
can read +/- 4 Volt range to 0.01 mV
REMOTE MONITORING CP FOR PIPELINES & TANKS
Accuracy:
•Digital Store and Transmit Accuracy
•e.g. 0.5% of reading or
0.1% of reading ±3 digits or whatever
Temperature & Environment Limits:
•Temperature Operating & Storage Limits for
stated Accuracy & for Failure
•Raintight
•Waterproof
REMOTE MONITORING CP FOR PIPELINES & TANKS

Power Supply
–Usually AC Powered
–Rechargeable battery backup
 How many hours operation while AC
out?
 Can send auto alarm?
 Stored Data & Operating Parameters
in non-volatile memory?
REMOTE MONITORING CP FOR PIPELINES & TANKS
Other desirable features for Rectifiers
•Synchronized Interrupter
•Time stamp for reading
•Temperature monitor
•Output adjustment
•Remote download of operating and monitoring
parameters
•Min/Max Error Reporting
•Alarm signals
•Any other suggestions?
REMOTE MONITORING CP FOR PIPELINES & TANKS
Test Stations
– On Potential
– Synchronized “Instant-Off” Potential
– Polarization Decay (leave impacting
rectifiers off for 4 or more hours?)
 Coupons
– On Potential
– Instant-Off Potential
– Polarization Decay

REMOTE MONITORING CP FOR PIPELINES & TANKS

Critical Bond Test Stations
– Current Flow in Bonds
 Measure in ± mV
 Measure to 0.01 mV
– Coupon (both On and Instant Off)
REMOTE MONITORING CP FOR PIPELINES & TANKS
 Test
Station Power
–Solar/Battery
–Long Life Battery
REMOTE MONITORING CP FOR PIPELINES & TANKS

Acquisition of Data
– SCADA
– Satellite
– Cellular Phone or Side Bands (Texting
Channels)
– Drive-By Radio
– Line of Site
 To high tower and then SCADA to Central
Area
 Unit to Unit to Central Monitor
REMOTE MONITORING CP FOR PIPELINES & TANKS

Transfer/Processing/Analyzing of
Data
–Who supplies software?
–What kind of Analysis?
–What format?
–How much customization is available
in preformatted form?
REMOTE MONITORING CP FOR PIPELINES & TANKS
What about
–Warranty
Reliability?
 How Long?
 On-Site
 What is included
 What is not included
 What about Software Upgrades
 What about Continued Support for
Installed System
REMOTE MONITORING CP FOR PIPELINES & TANKS
Questions