INDUCED AC interference
In cases where a structure, or tracer wires, parallel a high voltage AC (HVAC) power transmission circuit, significant AC potentials may be encountered. Hazardous AC potentials can occur on a structure as a result of induction, ground return currents, or faulted power circuits.
The close proximity of structures to AC power lines and their sharing parallel paths for relatively long distances is the principal cause of stray AC. A well-coated structure will normally result in higher induced voltages.
If the structure is remote from the power line(s), the interference can be virtually eliminated. Obviously, this method of mitigation is practical only at the pre-construction stage of either the power line(s) or the structure. Otherwise, the mitigation must be accomplished by alternative methods.
SITE SURVEYS
- Structure-to-Soil Potentials
- Synchronised Data Logging
- Coupon Measurements
- Soil Resistivity Surveys
- EMF (Electromagnetic Field) Measurements
- Longitudinal Electrical Field (LEF) Measurements
- HVAC Information Gathering - Liaison with HVAC Asset Owner
- Existing CP (Cathodic Protection) System Evaluation
MITIGATION MEASURES & INCREASED MONITORING
- Step & Touch Protection Systems
- Grounding / Earthing
- AC Discharge / Decoupling Devices
- Electrical Resistance (ER) Probes
- Real Time Corrosion Rates
- AC Current Densities
- Cathodic Protection System Effectiveness
- Isolation Joint / Insulating Flange Kit Protection
TECHNICAL CONSULTANCY
- Complete Modelling Suite
- Calculations
- Design Review
- Materials Specification & Evaluation
- Strategy & Policy Documents
- Ensure Compliance with Applicable Standards & Regulations