2024 Stray Current Remediation Construction and Anode Groundbed Maintenance Project

Through data analysis of the cathodic protection remote monitoring system, special stray current investigations and quarterly cathodic protection inspections, Guangdong Dapeng LNG Company Limited identified 4 pipeline segments along the entire route with AC interference voltage exceeding the standard limit (≥15 V), and 11 segments with current density surpassing the threshold (≥100 A/m²).

A 1 cm² corrosion coupon was buried for long-term monitoring (over 15 days), followed by continuous 24-hour measurement. The test results showed the average interference current density reached 171 A/m², with a peak value as high as 413 A/m². In addition, the instant off-potential of 2 sections failed to comply with specifications, measuring -0.813 V and -0.772 V respectively.

Targeting the above non-compliant conditions, construction for AC and DC stray current mitigation was immediately carried out after on-site verification to effectively reduce pipeline corrosion risks. Meanwhile, two additional anode wells were constructed to improve protection performance, addressing the excessive grounding resistance of the external anode groundbed at Meishi Station.