Investigation on Deposition Behavior of HVDC Water Cooling System Based on Electro-Mass Transfer-Velocity Coupling Model

The water cooling system plays an important role in the high-voltage direct current (HVDC) converter station. To reduce the leakage current among metal components, a certain number of platinum electrodes are installed at the distributary pipes. However, due to electric field distortion around the platinum electrode, over 66% faults of the cooling system are contributed by the frequently occurred sediment deposition on the platinum electrode. This paper proposed a method to predict the dynamic deposition behavior of the water cooling system through the built electro-mass transfer-velocity coupling model. Additionally, the deformation feedback effect of a sediment growth process is also included. An experimental water-cooling setup was established, and the simulated operation experiments were conducted to explore the deposition mechanism at first, then the mathematical coupling model was proposed to describe the corrosion and deposition characteristic. In addition, the arbitrary Lagrangian-Eulerian deformation method was adopted to count the feedback effect of the deposition product formation process on the multiple physical field model. The experiments and simulations were conducted to demonstrate the concept and verify the method. The results show that the proposed method can do well with the dynamic sediment deposition and radiator corrosion problem together. Meanwhile, the deposited sediment not only cause over 116-V voltage distortion around electrode but also induce another 3.2-mu A leakage current in radiators. As a result, the voltage balance ability of the electrode would be seriously destroyed and aggravate the deposition situation.