This paper presents resolutions to cathodic protection (CP) design restrictions at an Australian 1km
long steel-pile container wharf, requiring a 3,500A impressed current CP (ICCP) system. Rectifier
locations were confined to ends of the wharf, while all cablework from rectifiers to anodes and piles had
to be mounted underneath the dock. In a traditionally designed ICCP system using transformer-rectifier
units (TRUs) and low-voltage/high-current DC distribution, these restrictions would result in cable crosssections
of up to 120mm2 per anode leg. Instead, a novel DC power distribution system was utilized,
consisting of parallel channels of high-voltage/low-current Power Supply units (PSUs) feeding
adjustable constant current into Current Multiplier DC/DC converters located close to anodes. Thus,
power cables leading from PSUs could all be 1.0÷2.5mm2 twin-core cables, distributing 2A@300Vdc max towards each anode, where Current Multipliers transform it into 45A@9Vdc max. A single-anode prototype was developed as a proof-of-concept trial system, and then a full 77-anode ICCP system was constructed for the complete wharf corrosion protection. Major parameter values of the installed distribution cable network were considerably reduced – the average cable cross-section size by a factor of 30, the total cable weight by 12, and the total cable material and installation costs by 15÷20. Total
system power consumption from AC-mains was cut down by 55%.
Keywords: current multiplier, energy efficiency, impressed current cathodic protection,
marine corrosion, power distribution system