AC Interference on Pipelines and Buried Metallic Structures
Alternating Current (AC) interference is one of the most important integrity threats for buried pipelines and other metallic structures located near high-voltage power lines, electrified railways and industrial electrical installations.
Even when a pipeline is protected by a cathodic protection system, induced AC voltages and currents may create safety hazards for personnel and significantly increase the risk of AC corrosion.
Italcorr provides professional AC interference assessment, field measurements and mitigation solutions for pipelines, storage facilities and industrial infrastructures.
What is AC Interference?
AC interference occurs when alternating electromagnetic fields generated by high-voltage transmission lines induce electrical voltage on nearby buried metallic structures.
The induced voltage depends on several factors:
- distance from the power line;
- parallel exposure length;
- operating current of the electrical line;
- soil resistivity;
- coating resistance;
- pipeline geometry;
- grounding conditions.
If not properly controlled, AC interference may affect both personnel safety and pipeline integrity.
Typical Sources of AC Interference
The most common sources include:
- High Voltage Power Lines;
- Electrical Substations;
- Railway Traction Systems;
- Industrial Power Distribution Networks;
- Wind Farms;
- Solar Power Plants;
- Parallel Buried Metallic Structures.
Risks Associated with AC Interference
High AC voltage may result in:
- AC corrosion;
- accelerated coating degradation;
- electric shock hazards;
- interference with cathodic protection systems;
- increased maintenance costs;
- reduced asset life.
AC Corrosion
Unlike conventional electrochemical corrosion, AC corrosion may develop rapidly under specific conditions and produce deep localized pits.
The risk is generally influenced by:
- coating defects;
- soil resistivity;
- AC current density;
- moisture content;
- cathodic protection level.
Italcorr Services
Our services include:
- AC voltage measurements;
- AC current density measurements;
- Structure-to-Electrolyte Potential Measurements;
- ON/OFF Potential Surveys;
- Soil Resistivity Measurements;
- AC/DC Interference Assessment;
- Data Logger Installation;
- Continuous Monitoring;
- Technical Reports;
- Mitigation System Design.
Investigation Methods
Depending on project requirements we perform:
- AC Voltage Survey;
- DC Potential Measurements;
AC Mitigation Solutions
Depending on site conditions we design:
- grounding systems;
- gradient control wires;
- zinc ribbon grounding;
- decoupling devices;
- polarization cells;
- grounding electrodes;
- optimized cathodic protection systems.
Industries Served
Italcorr provides AC interference services for:
- Oil & Gas Pipelines;
- Water Pipelines;
- District Heating Networks;
- Refineries;
- Petrochemical Plants;
- Fuel Storage Terminals;
- Above Ground Storage Tanks;
- Underground Storage Tanks;
- Industrial Facilities;
- Power Transmission Corridors.
Benefits
Proper assessment and mitigation of AC interference allows operators to:
- improve personnel safety;
- reduce AC corrosion risk;
- extend pipeline service life;
- improve cathodic protection performance;
- comply with international standards;
- reduce maintenance costs.
Applicable Standards
Activities are performed according to internationally recognized practices including:
- EN 15280
- EN 12954
- ISO 15589-1
- ISO 15589-2
- NACE SP0177 / AMPP
- IEEE 80 (where applicable)
- IEC 60479 (electrical safety)
Why Choose Italcorr
Italcorr combines corrosion engineering, cathodic protection expertise and non-destructive testing to provide comprehensive AC interference investigations.
Our engineers perform on-site measurements, identify interference sources, evaluate corrosion risks and develop effective mitigation solutions for industrial assets throughout Italy.