The operating experience of several domestic converter stations indicated that the corrosion of the aluminum heat sinks is the leading cause of sediment deposition on grading electrodes

water pipe blockage and leakage in the inner cooling system of HV converter valves. In order to study the stay-current corrosion of heat sinks caused by electrolytic current in the inner cooling water

a simulating experimental platform is established in the laboratory.Through simulating experiments

the electrolytic currents in distributary pipes are detected. Using software simulation

the distribution of electrolytic current in the heat sink is revealed. Based on related theories

the stay-current corrosion quantity and non-electric corrosion quantity are calculated and comparatively analyzed. The experimental results show that the stray-current corrosion may occur only when the heat sink is at a higher electric potential than the medium potential of the valve section where it is installed. The main corrosion area in a heat sink is about 3.7 mm inward from the interface between the heat sink and the plastic pipe joint. In the field situation when the cooling water conductivity is strictly maintained below 0.5 μS/cm

the stay-current corrosion is probably not the leading cause of the corrosion in heat sinks.