【作者】 张杰；

【导师】 刘刚； 黄一；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2016， 硕士

【摘要】 柔性直流输电不需要依赖电网换相且无需无功补偿,可以向无源系统供电,占地面积小,适合于向导管架这样空间有限的无源系统供电。但当柔性直流输电系统发生换流器内部故障、直流电缆断线故障或直流电缆单极接地故障,或者电缆绝缘失效接地后继续柔性直流输电,会在海水中形成杂散电流,从而对导管架造成杂散电流影响。为了研究杂散电流对导管架及其阴极保护系统的影响,首先分析杂散电流电流路径并得到研究工况；对无阴极保护、外加电流阴极保护和牺牲阳极阴极保护三种保护状态导管架,在导管架接地流出杂散电流、导管架接地流入杂散电流、导管架处于杂散电流回路间和导管架处于杂散电流回路外四种情形下进行实海试验；对牺牲阳极阴极保护钢板在流出恒定和脉冲杂散电流进行实验室试验,研究杂散电流对钢板及其牺牲阳极阴极保护的影响。通过试验研究,得到了杂散电流对无阴极保护、外加电流阴极保护和牺牲阳极阴极保护导管架的影响规律,提出了判断存在杂散电流腐蚀的电流密度指标,比较了不同情形杂散电流对导管架的影响程度,同时也得到了杂散电流对牺牲阳极的影响规律；当外加电流阴极保护系统能够为导管架提供较为均匀保护电流时,通过调节外加电流阴极保护输出电流可以在一定程度上抑制杂散电流影响。更多还原

【Abstract】 HVDC-flexible doesn’t depend on line to commutate and doesn’t need reactive power compensation, so it can supply passive system and needs less space. It is fit for supplying passive system on the jacket where space is valuable. However, when voltage source converter fault, cable disconnection fault, cable grounding fault, or transmitting electricity after cable insulation breakdown occurs, there will be stray current in seawater which causes stray current corrosion of jacket. In order to research on stray current’s effect on jacket as well as its cathodic protection system, stray current path is analyzed, then research conditions are obtained. For jacket without cathodic protection, protected by impressed current, or protected by sacrificial anodes, experiments are done in the conditions that jacket discharges stray current, stray current flows into jacket, jacket lies in the path of stray current and jacket lies out of the path of stray current in the sea. For steel plate protected by sacrificial anode, laboratory experiments are done in the conditions that steel plate discharges constant and pulse stray current.According to experiment results, stray current’s effect on jacket without protection, protected by impressed current or sacrificial anodes, as well as sacrificial anodes is obtained, current density index which is used to determine whether stray current corrosion exists is proposed, stray current’s effect on jacket in different conditions is compared. When impressed current is uniform on the jacket, impressed current can be adjusted to be against stray current corrosion.更多还原