舰船轴频电场产生机理及控制技术

Ship′s shaft-related electric field mechanism of production and countermeasure technology

为了减小舰船轴频电场信号,在深入分析尾轴结构的基础上,建立轴频电场等效电路模型,明确碳刷和滑环接触电阻的波动是轴频电场产生的主要因素。在对主动式轴接地(Active Shaft Grounding,ASG)系统原理进行分析的基础上,研制了原理样机,并进行了实验室船模试验和海上实船试验。试验结果表明:所研制的ASG系统能有效抑制滑环和碳刷接触电阻变化所引起的轴频电场信号,抵消效果可达90%以上,且当轴地等效电阻在回路中的比例较大时,ASG系统开启后,将导致静电场信号增加。对ASG系统输出电流的影响因素进行分析,结果表明:ASG系统的最大输出电流与阴极保护状态密切相关,与航速关系不大。

In order to reduce the vessel′s shaft-related electric field, the equivalent circuit of shaft-related electric field was established on the basis of the analysis of the ship aft end structure, and it proved that the fluctuating resistance between the carbon brush and slip ring is the main factor that produces shaft-related electric field. The principle of the ASG(active shaft grounding) system was studied, and the prototype ASG system was developed and tested by shrinkage ratio ship model and real vessel experiments. The results showed that the shaft-rate electric field can be reduced effectively by 90% when the ASG system is employed. In addition, the ASG system will make static electric field increase when the resistance between the carbon brush and slip ring counts much in the equivalent circuit. After analyzing the factors that affect the output current of ASG system, it was found that the maximal output current is firmly related with the cathodic protection state, but not the sailing speed.