The BGCMAP corrosion system has been designed to help develop effective maintenance schedules for the electrical power industry.
The system provides a rapid and reliable way of assessing the potential life of steelwork using the Linear Polarisation Resistance (LPR) technique to determine the rate or corrosion.
Powered by rechargeable batteries, the system integrates GPS technology to provide an accurate location, date and time stamp for every test result.
The BGCMAP system glossary has been designed specifically for the power line industry and can be classified in terms of structure, component, line, segment, circuit and street. The user is also able to enter details of the inspector as well as soil and weather conditions.
The unit will automatically apply a current to the structure and determine Ecorr, from which the operator can then choose the best fit line to measure Rp.
Benefits of the BGCMAP corrosion system:
- On-site measurement of full LPR curve, ECorr and polarisation resistance
- Integrated GPS provides location date and time stamp for every test result
- Transmission line terminology
- Storage for over 700 results
- Battery operated, rugged unit for use in remote locations
- Lightweight and easy to transport
- User friendly Windows based software for reporting
- James Fisher Testing Services' complete testing package available
All of our equipment is supplied fully calibrated to UK national standards.
|BGCMAP system specifications|
Rugged site logger with waterproof connectors
|Keypad||Sealed colour coded and full alphanumeric keypad, tactile and audio feedback|
|Operating temperature||0 to +50°C|
|Screen||Monochrome LCD transflective with backlight
Contrast keypad adjustable
Display area 122mm x 77mm
Protective anti-reflective glass
|Connectors||Uniquely configured waterproof lemo type|
|Acquisition||2 channel, 16 bit acquisition at 10Khz sample rate
Pre-trigger on both channels
|Data transfer||USB-PC cable|
|Storage||700+ results, including full LPR curve, ECorr, Rp with full header information including site, structure, line, segment, weather, soil condition, date, time, latitude and longitude|
|Voltage range||ECorr +/- 20mV|
|GPS||Trimble Lassen SQ module with integral embedded antenna
Protocols are TSIP and NMEA 0183
Accuracy of the GPS is -
|Power||Battery: 1.2V NiMH rechargeable AA cells
Auto power off and battery indicator
|Battery life||8 hours + operation on full charge|
|Charge time||Approx 6 hours|
|Charging||External wall plug-in charger for 100/110/250VAC inputs (trickle charge)
External cigar plug-in charger for 12VDC inputs (fast charge)
|Dimensions||L 218mm x W 187mm x D 55mm|
|Type||Commercial CuCuSO4 half-cell fitted with porous ceramic plug and supplied ready filled with crystals|
The BGCMAP software operates under Windows XP and follows all of the usual file handling protocols. Files are downloaded from the site unit and are automatically entered into a report table.
From the table each file can be viewed independently and site data reviewed. The 'best fit' slope can be chosen to determine the polarisation resistance.
Corrosion of a steel element embedded in the ground is an electrochemical process. It acts as a galvanic cell in a similar way to a battery producing an electric current. This current can be measured on the surface as an electric field and compared with an electrode at a standard potential.
The BGCMAP operates by applying a current (ΔΙ) and recording the change in electric potential (ΔΕ) that occurs between the half-cell and the corroding sample. These values are plotted against each other. For small values around the free corrosion potential (Ecorr), the plot is assumed to be linear, the slope of which is the polarisation resistance (Rp).
Application to transmission tower legs
Carrying out the test on transmission tower legs is easy and rapid. The electrode spike is driven into the ground within 1m of the component, to a depth of at least 200mm.
The BGCMAP unit is connected to the component and the electrode using heavy duty steel clips. Any surface coating at the point of contact is removed beforehand. The copper / copper sulphate half-cell is then inserted firmly into the ground, in a small hole excavated alongside the component being tested.
The test is carried out automatically by the BGCMAP, which applies a current and records the voltage. The GPS co-ordinates and the date and time of the test are also recorded.