The PCM survey uses a low frequency 4 hertz (Hz) signal current to measure
current attenuation characteristics as well as to locate pipeline electrical contact (shorts) to other buried metallic structures.
* PCM
current attenuation across casing, which measures the magnetic field caused by AC current flow.
An excellent working were at IGBT that have a greater commutation times as MOSFET, which didn't present tops of voltage on charge during frequency rising, represented only voltage and
current attenuation on charge.
A pipeline's electrical characteristics of
current attenuation and distribution in response to this very low frequency (4Hz) signal are virtually the same as they are for an interrupted cathodic protection current.
Expertise in, among others, the areas of pipeline construction (conventional radiography, portable radiography, X-ray pipeline crawlers, automated ultrasonics AUT--girth weld, certified welding inspectors and asset integrity management); pipeline integrity (close interval potential survey, direct current voltage gradient survey, pipeline
current attenuation survey, pipeline depth of cover and survey, pipe line right-of-way GPS survey, pH soil analysis and continuous resistivity surveys, chemical and mechanical pipeline cleaning, MFL inline inspection tools and deformation/caliper tools).
In addition to confirming that the pipeline coating system is appropriate for the application of linear anodes, the linear anode system design must take into consideration the critical issue of voltage drop and its effect on
current attenuation.
JW's Pipeline Integrity Services offer the following services to the pipeline industry: Training, Field Supervision and Inspection,
Current Attenuation (such as PCM), Alternating Current Voltage Gradient (ACVG), Close Interval Survey (CIS), Direct Current Voltage Gradient (DCVG), Short Locating, Stray Current Mapping, Locating with sub-meter GPS, and Electronic Depths of Cover and data analysis for all services.