CC006 LFI, earthing and fault current

Competency ID and title	CC006 LFI, earthing and fault current
Competency area	Corrosion control
Stream/s	Design, Operations	Level	Elective

Competency descriptor
This competency requires a pipeline engineer to have a sound understanding of the various mechanisms by which stray AC and DC currents and voltages can be applied to a pipeline and how these can be managed and mitigated, in particular low frequency induction and earth potential rise associated with earthing of proximate structures and associated fault currents.

Competency application
This competency enables a pipeline engineer to oversee specialist personnel undertaking the design for, and management while in operation of, pipelines that may be affected by a range of structures that can impose AC and DC currents and voltages. The engineer will understand what impacts may occur in respect of the public, operating personnel, the pipe and its cathodic protection system and be able to ensure that these are designed for, or ensure, appropriate procedures to provide protection are in place for operating pipelines. They will work with and commission electrical specialists, but do not need to have the capability to undertake the design or assessment work themselves.

Prerequisites
CC001 – Corrosion control fundamentals
CC002 – Cathodic protection systems

Competency elements

Element type	Element description
Knowledge	Types of interference and their nature and impact DC interference AC interference telluric interference lightning.
	Sources of interference AC and DC transit systems welding operations cathodic protection systems high voltage transmission systems AC & DC power generation fault currents earthing telluric (geomagneticly induced) currents lightning.
	Mechanisms low frequency induction continuous earth leakage earth potential rise capacitive coupling telluric induction.
	Impact of each form of interference including: personnel/public safety (touch voltages) AC corrosion pipeline and coating damage equipment damage – CP systems, telemetry, pipe monitoring equipment.
	AS/NZS 4853 – Electrical hazards of metallic pipelines Key elements o safety and risk o electrical hazard sources o design process o electrical hazard control o commissioning and maintenance of pipeline earthing o regulatory requirements.
	Design for electrical hazard control for each mechanism: design process including data gathering calculation of interference currents and voltages and limits mitigation methods testing and monitoring.
	Hazard control during operations and maintenance: assessment of risk sources preparation of procedures personal protective equipment other protective equipment.
Experience	At least 18 months in a role that includes a proportion of time working with specialists undertaking the assessment and management of LFI, capacitive coupling, EPR and telluric interference
Expertise	identifies the potential for LFI, capacitive coupling and EPR briefs and scopes work to be undertaken by electrical specialists designing mitigations for electrical interference consistent with AS 4853 understands and applies reports and recommendations by electrical specialists obtains advice on protection of personnel, pipelines and equipment that may be subject to electrical interference ensures mitigation methods are in place and maintained.

Resulting capabilities of competency

Capable of overseeing the assessment and design of, and provision of operational advice about, the full range of electrical interference types and mechanisms.

Capable of commissioning and scoping the work of electrical specialists in assessment of pipeline electrical interference and interpreting and applying the specialists’ reports and recommendations, either for design for a new pipeline or inspection and assessment of an operating pipeline.

CC006 LFI, earthing and fault current

Corrosion Control