SU1453330A1 - Magnetooptic method of measuring current intensity - Google Patents

Abstract

This invention relates to electrical measuring technology. The purpose of the invention is to expand the range of measured currents. The light beam divider 7 forms, from the optical radiation of the radiation source 8, beams which are transmitted through the 1.2 Farad cells. The latter are made of materials with different Cond verd. The analyzed radiation beams are converted into an electrical signal by photodetectors 13–16. Performing Farade cells from materials with different constant Verde allows using the computing unit 17 to determine the measured current by the difference of the angles of rotation of the polarization plane of the radiation. 1 il. i (/)

Description

The invention relates to electrical measuring equipment, in particular, to magneto-optical converters based on the Farad effect, and can be used to measure the current in high-voltage power plants.

The purpose of the invention is to expand the range of measured currents.

Two start-ups of linearly polarized optical radiation are formed and passed, respectively, through the first and second magneto-optical media with a different constant Verde, which are placed in the magnetic field of the measured current. The sines of the deflection angles of the planes of polarization of the beams of linearly polarized optical radiation transmitted through the first and second magneto-optical media are measured. The difference between the angles of deflection of the planes of polarization of the beams of the linearly polarized optical jKoro radiation is calculated, and the strength of the measured current is determined from this difference.

The drawing shows a block diagram of a device that implements the proposed method.

Farad cells 1 and 2, the working bodies of which are made of magneto-optical media with) Verde's various constants, are marked (in the magnetic field of the measured current. The inputs of Farada cells 1 and 2 are optically coupled through polarizers 3 - 6 and divider 7 of the light. flow with radiation source 8. The transmittance planes of polarizers 3-6 are installed parallel to one another. The outputs of cells 1 and .2 Faradus are optically connected through analyzers 9-12 to photoreceivers 13-16, which are connected to the inputs of the computing unit 17. The transmittance planes of the first 9 and third 11 The analyzers are installed parallel to the transmission planes of polarizers 3-6, and the transmission planes of the second 10 and fourth 12 analyzers are installed at an angle of 45 to the transmission planes of polarizers 3-6.

A device that implements the magneto-optical method for measuring current strength works as follows.

The radiation of the source 8 is divided by a divider 7 of the light flux into four parts, converted by polarizers 3-6 into four linearly polarized radiation fluxes, the plane

five

0

five

0

five

0

five

0

five

the polarizations of which are set parallel to each other, and enter the cells 1 and 2 of Farad. The polarization planes of the radiation flux transmitted through the Farad cells 1 and 2 are rotated by angles proportional to the strength of the measured current and the Verde constant of the working bodies of the Farada cells 1 and 2. After analyzers 9-12, the rotations of the polarization planes are converted into variations in the intensity of the fluxes, which are converted by the photoreceivers 13-16 into electrical signals. The transmittance planes of the first 9 and third 11 analyzers are installed parallel to the transmittance planes of polarizers, and the transmittance planes of the second 10 and fourth 12 analyzers are set at an angle of 45 to the plane, passing polarizers, therefore, the expressions for the voltages at the outputs of the first 13 K, and third 15 uj photodetectors have the form

and, Ф, 3, COS2IV, | Ф, 8, (1 + cos2IV,) k, (1 + cos2IV);

Uj 1 ФЗЗ cosz P} Sj (H-cos2lVj)

k3 (1 + cos2lVj),

a at the outputs of the second 14 Uj and fourth 16 U4 photodetectors

u1 | f232C08CH1U, - |) | Pr8L1 + - 1 + sin2IV,) k, j (1 + sin2IV,);

(P4S4COs4.IV, - 1), (1 + + sin2IV, i) k4 (1 + sin2lVi),

where (P,, g, Pj, are the intensities of the flows coming out of polarizers 3-6; S ,, 84,8,84 are the sensitivity of the photoreceivers 13 13; V, V, and V are Verde constants

working bodies of cells 1 and 2 Farad; I - force measured

current;

k 9; S; / 8 - proportionality coefficient (i 1,2,3,4).

Computing unit 17 processes the output signals of photodetectors 13 - 16 according to the algorithm

N

D)

Usb.2 (v: iv:) (- -t-) .-

where N is the proportionality factor of the computing unit 17. From the expressions for U, jUj ,, jU it follows that the output voltage of the computing unit 17 is related to the measure e-b

my current expression

Narcsinfsin | 2I (V, -Vj D v.kh- 2 (V, -VjJ) If the difference in the rotation angles of the polarization plane in cells 1 and 2 of Farad is within ± 45 °, i.e. -AZ I (V, - Vj) 64–45% This output voltage of the computing unit 17 is proportional to the measured current Ug N1.

Formula

the invention

The magneto-optical method for measuring the current, which consists in forming a beam of linearly polarized optical radiation, passes it through the first magneto-optical medium placed in a magnetic field.

. five

ten

3330

of the measured current, the sine of the deflection angle of the polarization plane passed through the first magneto-optical medium of the linear polarization optical radiation, which is characterized by the fact that, in order to expand the range of the measured currents, the second beam of the linear polarized optical radiation, in the magnetic field of the measured current is placed a second magneto-optical medium with a constant Verde, different in magnitude from the Vertical first Verde of the first magneto-optical medium, the second beam is passed linearly polar optical radiation through the second magneto-optical medium and the sine of the deflection angle .20 of the polarization plane passing through the second magneto-optical medium of a beam of linearly polarized optical radiation, calculate the intensity of the deflection angles of the polarization plane of linearly polarized optical radiation and From the difference obtained, the strength of the measured current is determined.

Claims (1)

Claim The magneto-optical method of measuring current strength, which consists in forming a beam of linearly polarized optical radiation, passing it through a first magneto-optical medium placed in a magnetic field of the measured current, measuring the sine of the angle of deviation of the plane of polarization transmitted through the first magneto-optical medium of a linearly polarized optical beam radiation, characterized in that, in order to expand the range of measured currents, a second beam of linearly polarized optical radiation is formed, in ma The second field of linearly polarized optical radiation is transmitted through the second magneto-optical medium and the sine of the angle of deviation of the plane of polarization passing through the second magneto-optical medium of the beam linearly polarized optical radiation, calculate the difference between the angles of deviation of the plane of polarization25 beams of linearly polarized optical radiation values and the resulting difference determine the strength of the measured current.