公开(公告)号：EP1482315A4

公开(公告)日：2008-04-23

申请号：EP03707182

申请日：2003-02-28

申请人： TOKYO ELECTRIC POWER CO ,  NAMIKI PRECISION JEWEL CO LTD

发明人： KUROSAWA KIYOSHI ,  HIROKI YOSHIHARU ,  KONNO YOSHIHIRO ,  SASAKI MASARU

IPC分类号： G01R15/24

CPC分类号： G01R15/246

摘要： A current measuring device comprising a current detector (10) and a photoelectric converter (20). The detector (10) is provided with an optical fiber sensor (11) installed to encircle the outer periphery of a conductor (30), and the sensor (11) is provided at one end side thereof with a reflection film (12) so as to effect reflection at the end thereof. The current detector (10) comprises a first Faraday element (13), a light-transmitting double refraction element (14), a first optical fiber (15), a second optical fiber (16), and a lens (17). The Faraday element turns the polarization surface of an incident light almost 22.5°. The double refraction element (14) has the functions of separating an output light from the sensor (11) into a normal light L1 and an abnormal light L2 mutually crossing perpendicularly, and transmitting linearly polarized light L0 emitted from a light source. The lens (17) is disposed between the element (13) and the double refraction element (14), with image forming points set at the incident end (11a) of the sensor (11) and at a core at one end surface (15a) of the first optical fiber (15). Accordingly, constituting parts are reduced in number to thereby reduce the size of the device.