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Direct Electrical Heating (DEH) Subsea Flowline Calculator engineering
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Direct Electrical Heating (DEH) Subsea Flowline Calculator

Model single-phase 50/60 Hz AC power delivery, current division between pipeline and seawater, and active heating duty (W/m) to prevent hydrate plugs.

Pipeline & Electrical System Parameters

Typical subsea hold temp duty: 60-120 W/m
Includes steel skin effect at 50/60 Hz
Parallel return path through open sea
Uncompensated loop power factor

DEH Power & Sizing Results

Required Cable Supply Current:
Topside Supply Voltage:
Total Active Power:
Apparent Power (S_total):
Topside Capacitor Bank Required:
Pipe Current Share:

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Direct Electrical Heating (DEH) Architecture

Direct Electrical Heating is an advanced flow assurance system that prevents hydrate and wax deposition in long subsea tiebacks during unplanned production shutdowns. A single-phase AC current is driven down a piggyback cable strapped to the insulated pipeline and connected to the pipe steel at the far-end subsea template.

Current Division & Skin Effect

The return current naturally splits between the conductive carbon steel pipeline shell (typically 55% to 65%) and the surrounding seawater (35% to 45%). At 50/60 Hz, the ferromagnetic nature of steel concentrates current in an outer skin layer of only 1 to 3 mm, substantially increasing the effective AC resistance and generating Joule heat ($P = I^2 R$).

Frequently Asked Questions