JPH01120668U

JPH01120668U -

Info

Publication number: JPH01120668U
Application number: JP1475688U
Authority: JP
Priority date: 1988-02-05
Filing date: 1988-02-05
Publication date: 1989-08-16

Description

[Brief explanation of the drawing]

第１図は本考案の零相電流検出装置の原理構成
図。第２図はフアイバ型偏光子の波長―損失特性
グラフ。第３図は従来の零相電流検出装置の原理
構成図。Ｓ_ａ，Ｓ_ｂ，Ｓ_ｃ……フアラデー素子、Ｃ_ａ，
Ｃ_ｂ，Ｃ_ｃ……コア、Ａ，Ｂ，Ｃ……電線、Ｉ_ａ，Ｉ_ｂ，Ｉ_ｃ……電線を流れる電流、Θ_ａ，Θ_ｂ，Θ_ｃ……各フアラデー素子でのフアラデー回転
角、Ψ_ａ，Ψ_ｂ，Ψ_ｃ……隣接フアイバ型偏光子
のオフセツト角、Ｆ１〜Ｆ_４……フアイバ型偏光
子、１……発光素子、２……受光素子、５……モ
ニタ、６……バンドパスフイルタ。 FIG. 1 is a diagram showing the principle configuration of the zero-sequence current detection device of the present invention. Figure 2 is a wavelength-loss characteristic graph of a fiber polarizer. FIG. 3 is a basic configuration diagram of a conventional zero-sequence current detection device. S _a , S _b , S _c ... Faraday element, C _a ,
C _b , C _c ... Core, A, B, C ... Electric wire, I _a , I _b , I _c ... Current flowing through the wire, Θ _a , Θ _b , Θ _c ... Faraday rotation angle in each Faraday element, Ψ _a , Ψ _b , Ψ _c ... offset angle of adjacent fiber polarizers, F1 to F ₄ ... fiber polarizer, 1 ... light emitting element, 2... Light receiving element, 5... Monitor, 6... Bandpass filter.

Claims

[Scope of utility model registration request]

Zero-sequence current I _o = I a + of three-phase alternating current I _a , I _b , I c flowing through three electric wires A, B _, and _C separated from each other
A zero-sequence current detection device for detecting I _b + I _c , which includes equivalent gapped ferromagnetic cores C _a , C _b , C _c that are provided to surround each wire and generate magnetic flux density proportional to the current. Then, the light emitting element 1, the light receiving element 2, and the light emitting element 1 provided on the ground side are connected to the first
a second fiber polarizer _F2 that guides light emitted from _the output end of the Faraday element _Sa to the input end of the second Faraday element _Sb _; A third fiber polarizer F3 guides the light emitted from the output end of the Faraday element _Sb to the input end of the third Faraday element _Sc , and a third fiber polarizer _F3 guides the light emitted from the output end of the Faraday element _Sc to the ground side. The fourth fiber polarizer F ₄ leads to the light receiving element 2, and the offset angle _{Ψ a} of the characteristic polarization direction of the adjacent fiber polarizers F ₁ and F ₂ , F ₂ and F ₃ , F ₃ and F 4 , Zero-sequence current detection characterized in that Ψ _b and Ψ _c are all equal and not 0, the light receiving element 2 converts the intensity of light into an electrical signal, and the zero-sequence current is determined from the fundamental frequency component of this signal. Device.