STRAY CURRENT
ICG STRAY CURRENT DATA LOGGING AND MONITORING
Over the past 5 years, Infinity Corrosion has helped utility owners and light-rail transit (LRT) system operators work cooperatively to develop a Stray Current Data Logging and Monitoring Program. Long-term data logging is an effective way to monitor dynamic stray currents providing the following benefits:
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Identifying improvements from system upgrades
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Identifying LRT or pipeline component failure
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Improve field data consistency
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Detect the effects of LRT system operational changes and maintenance activities on stray currents
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Assess pipeline cathodic protection levels
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Identify patterns and the duration of adverse effects on pipelines caused by stray currents due to seasonal weather and precipitation effects
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Document the impact and effectiveness of a stray current program
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Provide graphical presentation of data that enables non-technical management and decision makers to better understand the effectiveness and value of the stray current program.
Stray current is caused when current intended for return along the rails, leaks or discharges from the rails to the ground. Current discharged into the ground flows along paths of least resistance which can occur through highly conductive (low resistivity) soils and metallic conductors such as pipelines. Once current is picked up on the unintended conductor it can travel along and discharge from the conductor to return to the traction power substation.
The stray current process not only impacts the integrity of utilities but also light-rail components at the points of discharge. While most light-rail transit agencies integrate common industry practices during construction in an effort to limit stray current, this problem can still occur. Train movement, utility types, utility configurations, soil resistivity, and lack of regular maintenance can all be contributing factors to the increase in stray current and degradation of a system.