Analysis and Diagnosis of Offset and Water Leakage in Main Water Pipes Between Valve Tower Layers of Converter Station

Converter valves are the core equipment of converter stations in high-voltage direct current transmission systems, responsible for converting electrical energy between AC and DC systems. Currently, converter valves in operational projects generally adopt a suspended air-insulated water-cooled valve tower structure, which requires a large number of cooling water pipes to be arranged in the valve tower for heat dissipation. This paper introduces a case of water leakage caused by uneven stress and damage to the sealing ring after long-term operation, resulting from improper alignment of the main water pipe during the installation of the valve tower at a ±800 kV UHV converter station. Through extensive investigation and analysis of the fault phenomena, the mechanism of the fault occurrence is explored. Based on the conclusions of the fault analysis, standardized installation processes and inspection methods have been formulated, and suggestions for subsequent hidden danger investigation and analysis in operational projects have been put forward.