舰船极低频电场的产生机理及其防护

Generation mechanism of ship′s ELFE and its protection

舰船极低频电场由于能在海水中传播到很远的距离,而且很容易被探测到,已成为舰船的一个重要目标特性.螺旋桨转动调制舰船腐蚀电流和外加电流阴极保护系统在海水中产生的电流是舰船极低频电场的2个重要来源.质量较差的阴极保护系统(ICCP)中的电源滤波器也会导致极低频电场的产生.电磁场防护结构工艺、被动轴接地系统、主动轴接地系统和电场抵消系统是目前降低舰船极低频电场的主要方法.

The ship′s extremely low frequency fields (ELFE) transmitted to a far distance and easily detected in the sea-water, has became an important characteristic of a ship. The corrosion currents of propeller revolution modulation and the currents which results from impressed current cathodic protection system (ICCP) are two important sources of ELFE. The power supply filter of poor quality which is often used in ICCP can also lead to ELFE. The main methods used to reduce ELFE include electromagnetic field protection technology, driven shaft earthing system, drive shaft earthing system and electric field counteracting system.