11 results about "Optical current transducer" patented technology

The invention discloses a dual-polarization multi-layer optical current sensor and a multi-physical field disturbance resisting method thereof, and belongs to the technical field of current sensors of power systems. The sensor comprises a dual-polarization multi-layer sensor system and a dual-polarization multi-layer optical current sensor real-time signal processing system which are connected with each other, the output end of a double-layer diamagnetic photoelectric sensing signal processing unit and the output end of a temperature-resistant signal photoelectric sensing signal processing unit in the real-time signal processing system of the dual-polarization multi-layer optical current sensor are connected to the input end of a dual-polarization multi-layer signal processing unit; and the output end of the dual-polarization multi-layer signal processing unit is connected to the multi-physical field anti-interference signal output unit. According to the invention, the resistance of the straight-through optical path type MOCT to ambient temperature field fluctuation can be effectively improved, and the influence of external magnetic interference at any position and the influence of ambient temperature fluctuation interference can be resisted.

The present invention discloses a stacked optical current sensor and an anti-external magnetic interference method thereof, which belong to the technical field of electric power sensors. The stacked optical current sensor includes: a sensor device and a stacked optical current sensor real-time signal processor. This optical current sensor includes a lower layer and an upper layer sub-sensor, whose sensing magneto-optical optical path structure is placed on the long side or short side of a symmetrical polygon, and the upper layer sub-sensor is placed after the rotation angle is taken as the center of the lower layer sub-sensor. The anti-external magnetic interference method is that the current conductor to be measured is placed at the center of the stacked optical current sensor, and the interference current conductor can be located at any point outside the stacked optical current sensor. At this time, the magnetic field integrals of the interference current on the sensing magneto-optical optical path structures of the upper and lower layers of sub-sensors show the characteristics of being mutually inverted. The signal processor performs superposition and cancellation processing on the signals obtained from the two layers of sub-sensors to eliminate the influence of the magnetic field of the interference current, and thus obtain a high-precision current measurement result.

To provide a simple and highly accurate photocurrent sensor.SOLUTION: A photocurrent sensor comprises: a polarized light separation portion provided between a light source and an optical fiber; a reflection portion provided at the other end of the optical fiber to reflect measurement light transmitted through the polarized light separation portion and incident on the optical fiber and including an optical rotator for optically rotating incident polarized light by approximately 45 degrees; a sensor fiber provided between the polarized light separation portion and the reflection portion; a detector that converts the measurement light subjected to intensity modulation by reciprocating in the sensor fiber and passing through the polarized light separation portion again into an electric signal.SELECTED DRAWING: Figure 1

The present application relates to a kind of stress line birefringence compensation method of optical current sensor, the optical current sensor includes laser source, polarizer, magneto-optical film, nanometer ring-shaped radial polarization grating, image beam and CMOS area array camera sequentially arranged in same optical path, the method includes the following steps: utilize laser source to emit light signal, under the action of current to be measured, the output signal of optical current sensor is superposed with Faraday magnetic rotatory angle θ And stress line birefringence δ, form synchronous rotating annular light spot;Determine the zero-crossing moment of the measured alternating current, the rotation angle of corresponding annular light spot is stress line birefringence δ at zero-crossing moment by CMOS area array camera and record;Based on the stress line birefringence δ of record, utilize model-free adaptive iterative learning method to predict the stress line birefringence δ of future time, and according to the prediction result, the output signal of optical current sensor is compensated.

The application discloses a kind of independent double strip optical current sensor and its anti outside temperature fluctuation interference method belonging to the field of intelligent measurement and sensing technology of electric power system.The sensor includes mutually connected sensing unit and signal processing unit, wherein the output end of multi-frequency modal decoupling signal processing device is connected with the input end of double strip optical current sensor signal processing device, the output end of double strip optical current sensor signal processing device is connected with the input end of measurement signal output device;Sensing unit is provided with double strip sensing unit main structure including measurement sensing optical path structure and temperature compensation sensing optical path structure, the vertical distance of the midpoint of measurement sensing optical path structure and temperature compensation sensing optical path structure to the current to be measured is equal.The application can realize the measurement function of temperature resistance while ensuring the long-term operation stability of single straight-through optical path type optical current sensor, and the advantages of simple structure.

The invention discloses an independent double-strip-shaped optical current sensor and an external temperature fluctuation interference resisting method thereof, and belongs to the technical field of intelligent measurement and sensing of a power system. The sensor comprises a sensing unit and a signal processing unit which are connected with each other, the output end of a multi-frequency modal decoupling signal processing device is connected with the input end of a double-strip-shaped optical current sensor signal processing device, and the output end of the double-strip-shaped optical current sensor signal processing device is connected with the input end of a measurement signal output device; the sensing unit is provided with a double-strip-shaped sensing unit main body structure comprising a measurement sensing light path structure and a temperature compensation sensing light path structure, and the vertical distances from the midpoints of the measurement sensing light path structure and the temperature compensation sensing light path structure to the current to be measured are equal. According to the invention, the temperature-resistant measurement function can be realized while the advantages of high long-term operation stability and simple structure of the single straight-through light path type optical current sensor are ensured.

The present invention proposes a stress line birefringence compensation method for an optical current sensor based on crystal cleavage interference and peak detection circuit, aiming at the problem that stress line birefringence is generated in the magneto-optical thin film and transmission optical fiber due to temperature change and vibration, and it is difficult to separate and compensate because it is aliased with the Faraday magneto-optical rotation angle. The present invention realizes that the optical current sensor can linearly demodulate the Faraday magneto-optical rotation angle based on crystal cleavage interference; when there is stress line birefringence, the output of the optical current sensor is the linear superposition of the Faraday magneto-optical rotation angle and the stress line birefringence; the peak detection circuit is used to determine the peak value of the alternating current to be measured. At this time, the Faraday magneto-optical rotation angle is 90°. The difference between the output signal of the optical current sensor and the Faraday magneto-optical rotation angle is the stress line birefringence, which can be detected and compensated.

The present invention provides an AC zero-crossing compensation method for stress line birefringence in an optical current sensor. The method comprises the following steps: Step S1: Light emitted by a light source passes through a polarizer to form linearly polarized light. Under the action of a magnetic field to be measured, the linearly polarized light passes through a magneto-optical film and forms a Faraday magneto-rotation angle, which is then analyzed by a Newton circular polarization grating. Step S2: When the environment in which the optical current sensor is located experiences temperature drift or vibration, the Newton circular polarization grating converts the Faraday magneto-rotation angle and the stress line birefringence generated by the optical element and the magneto-optical film into synchronous rotation of a light spot image, and outputs a linear superposition result of the Faraday magneto-rotation angle and the stress line birefringence. Step S3: When an AC current passes through zero, the current magnetic field is zero, causing the Faraday magneto-rotation angle to be zero. At this time, the output of the Newton circular polarization grating is the interference value corresponding to the stress line birefringence caused by the current temperature drift or vibration. The present invention can extract and compensate for the stress line birefringence when the AC current passes through zero.

This invention discloses a single-path dual-channel optical current sensor device and a self-compensation testing method. The method and device can achieve four-AD sampling and bidirectional demodulation of the same current sensor optical path, and automatically compensate for temperature-induced errors. The method includes an optical path unit, a circuit unit, and a data processing unit. The optical path uses a coupler to split the light source into two beams. Utilizing the symmetry of the sensing optical path, dual-channel demodulation is achieved, and an isolator is used to achieve unidirectional light output, avoiding bidirectional light interference with the light source and signal power. Each channel uses dual-AD differential demodulation, and a beam splitter ensures that the differential signals are of equal magnitude. Coupler 2 is used to monitor the light source power. The circuit unit includes a light source driver, temperature control and drive closed-loop control, a signal filtering and amplification unit, and a DSP or microcontroller for AD acquisition and signal processing. The data processing unit includes a current signal demodulation algorithm and a self-compensation method.

An optical fiber break detection method includes: acquiring multiple current sampling data of a photodiode in an optical current transducer; respectively performing wavelet transform on the multiple current sampling data to obtain a detail coefficient corresponding to each of the current sampling data; and determining an on / off state of an optical fiber in the optical current transducer according to the detail coefficients corresponding to the multiple current sampling data. This solution achieves the detection of an optical fiber break within a relatively short time, thereby reducing the occurrence of malfunction in a relay protection apparatus in case that an optical fiber break occurs. An apparatus and the relay protection apparatus are configured for implementing the method.

This invention relates to an AC zero-crossing compensation method for stress line birefringence in an optical current sensor. The optical current sensor includes a laser source, a polarizer, a magneto-optical thin film, and a radial polarization grating arranged sequentially on the same optical path. The method includes the following steps: emitting an optical signal using the laser source, which passes sequentially through the polarizer, the magneto-optical thin film, and the radial polarization grating. Under the influence of the current to be measured, the output signal is superimposed with the Faraday magnetostrictive rotation angle α and the stress line birefringence γ, forming a translated strip-shaped light spot; locating the position of the strip-shaped light spot using a position-sensitive detector and measuring the rotation angle of the polarization plane of the linearly polarized light; detecting the AC zero-crossing point of the current to be measured, and acquiring the rotation angle of the polarization plane measured by the position-sensitive detector at the zero-crossing point as the stress line birefringence γ; and compensating the output signal of the optical current sensor using the acquired stress line birefringence γ.