96 results about "Optical current transducer" patented technology

The invention provides an optical current sensor, relating to current detection equipment. The optical current sensor mainly comprises four parts: a magnet collecting ring optical sensing head, a polarized light system, a signal detection system and a power supply; as the optical current sensor of the invention has the advantages of high sensitiveness, quick response, high measurement exactness, low cost, online monitoring changes of the current amplitude and frequency of conductors to be measured in real time, facilitating the connection with digitizer, realizing the real-time online monitoring of computer and the like, the optical current sensor of the invention can be widely applied to the detection of power system transmission currents and currents used for large mine enterprises, especially for the current detection of high voltage and ultra-high high voltage power network.

The invention discloses an optical current sensor based on the Faraday magneto-optic effect. The optical current sensor comprises a laser generator which is used to generate polarized laser of a set wavelength, an integrated probe which comprises a magneto-optical medium, a photodetector which is used to convert an optical signal into an electrical signal, and a data analyzing and processing device which filters out noise through the combination of hardware filtering and software filtering to acquire a good response effect. A polarizer and an analyzer are arranged on two ends of the magneto-optical medium respectively, and are insulatedly packaged on both ends of the magneto-optical medium respectively. The laser generator and the polarizer are connected through an optical fiber path, andthe photodetector and the analyzer are connected through an optical fiber path. The invention further discloses a current measurement method of the optical current sensor based on the Faraday magneto-optic effect.

The invention discloses a method for calibrating dynamic performances of an FOCT based on voltage modulation. Additional voltage modulation phases are introduced in a digital closed-loop signal processing process of the FOCT to simulate optical nonreciprocity Farady phases caused by power line currents, segment treatment is performed to output data of the FOCT by using a segment modulation phase method to calibrate scale factors of the FOCT, and the linearity, the symmetry and the repeatability of the scale factors of the FOCT are analyzed. According to the method, the method starts from a digital closed-loop signal processing process of the FOCT, dynamic performances of the FOCT are estimated overall, the method has the advantages of being simple and direct in testing process and high in calibration accuracy, and test calibration of a plurality of sets of FOCTs can be completed for one time.

Wiring in new and older aircraft use bundled insulated conductors that are subject to deterioration over time that can result in on-board fires, loss of in-flight control and eventual crashes of the aircraft. The present invention provides a diagnostic method which permits the on-line and non-destructive diagnosis of the insulation degradation in a portion of the wiring comprising: a) measuring the current flow at locations of the aircraft wiring utilizing an optical current sensor with a bandwidth of dc to 50 kHz; b) determining the current flow within a high frequency bandwidth; and c) analysing the results of the current flow differential determination and initiate the following: i) detect and locate the point of cable failure; ii) initiate an alarm annunciation; and iii) initiate an on-board sectionalized fire suppression system.

The invention discloses a method for online monitoring the state of a fiber-optical current transducer and conducting self-diagnosis. The method includes the following steps: using a second photoelectronic detector which is arranged at a port of a coupler of the fiber-optical current transducer to monitor the output light power of a superluminescent light-emitting diode (SLD) light source in the fiber-optical current transducer and transmit the output light power to a light source state control and self-diagnosis module; a current monitoring module monitoring drive current and transmitting the drive current to the light source state control and self-diagnosis module; a temperature monitoring module monitoring the working temperature of a chip of the SLD light source by measuring the resistance of a thermistor and transmitting the working temperature of the chip to the light source state control and self-diagnosis module; the light source state control and self-diagnosis module separately comparing the output light power of the SLD light source, the working temperature of the chip and the drive current with corresponding normal state working values in a database, and conducting self-diagnosis on the working state of the SLD light source on the basis of the result of the comparison, and acquiring self-diagnosis information.

An optical current sensor having a reflection interferometer (1, 10) has, in its fiber-optic lead (2), a polarization-maintaining first fiber branch (20) for two forward-traveling orthogonally polarized waves and a polarization-maintaining second fiber branch (20′) for two backward-traveling orthogonally polarized waves. In this case, the two fiber branches (20, 20′) are connected to one another via a coupler (8) on the sensor side. The first fiber branch (20) is connected to a light source (4) and the second fiber branch (20′) is connected to the detector (5). A means for phase shifting (7) is funcionally connected to at least one of the fiber branches (20, 20′). It is thus possible to achieve a quasi-static control of the phase shift of the waves, so that less stringent requirements can be made of the means for phase shifting than of the phase modulators that are usually used in current sensors of this type.

The object of the invention is to provide a method and a system for fixating a Faraday optical current sensor (12a, 12b, 12c) in a suitable measurement position for measuring the current in a 3-phase cable (14). The 3-phase cable (14) comprises 3 individual section-shaped phase conductors (16a, 16b, 16c) insulated in relation to one another and encapsulated inside an insulator (18). The method comprises the provision of a Faraday optical current sensor arrangement comprising 3 Faraday optical current sensors (12a, 12b, 12c), each Faraday optical current sensor being fixated in a specific position outside the section-shaped phase conductors (16a, 16b, 16c), and the provision of a processing unit for calculating a current value from a magnetic field value. The method is performed by measuring 3 magnetic field values by using each of the 3 Faraday optical current sensors (12a, 12b, 12c) and calculating the current in each of the section-shaped phase conductors (16a, 16b, 16c) by using the processing unit and the 3 magnetic field values.

The invention relates to a self-calibration method for realizing an optical voltage sensor, which relates to a self-calibration method for a sensor. A reference voltage source is designed to realize a self-calibration function of the optical voltage sensor. By using the current optical voltage sensor, measurement precision and temperature stability are low. By using the optical voltage sensor of the invention, the above problem can be solved. In the invention, a discrete Fourier algorithm is used to acquire an effective value of a voltage signal. Through adding a calculation sample number and windowing processing, influence of frequency fluctuation on effective value calculation can be reduced and the stability of a self-calibration coefficient can be increased. An optical voltage sensor measurement result is affected by a temperature. By using an optical current sensor in the invention, the above problem can be solved. Through testing, the measurement precision reaches an IEC 0.2 grade measuring requirement in a temperature scope of minus 40-60 DEG C. The sensor and the method are suitable for designing a voltage transformer.

An optical current or magnetic field sensor has a sensor head which has a first phase delay element (13), a second phase delay element and a sensor fiber (15) The two phase delay elements (13) are optically connected to opposite ends of the sensor element (15), and the phase delay angle rho on at least one of the phase delay elements (13) deviates by an angle epsilon, with epsilon<>0°, from 90°. Linearly polarized light waves (3) are injected into the first phase delay element (13), with a polarization axis (y') of these linearly polarized light waves (3) including an angle which deviates from 45° by an angle Deltaalpha, with Deltaalpha<>0°, with a principal axis (y) of the first phase delay element (13). The angle Deltaalpha is selected as a function of at least the angle epsilon. This choice of the angle Deltaalpha makes it possible to compensate for non-linearities between a direct measurement signal and an electrical current or magnetic field to be measured which occur because of the angle epsilon<>0°.

A method of measuring a current of a current carrying cable teaches the first step of providing an optical sensor assembly comprising a base unit, and an optical current sensor mounted on the base unit for transmitting a beam of polarized electromagnetic radiation to an optical fiber. A light detector is also provided having a first channel that operably connecting the light detector to an analog to digital converter through a programmable gain amplifier, a second channel that operably connects the light detector directly to the analog to digital converter, and a processor operably connected to the analog to digital converter. The optical sensor assembly is mounted adjacent the current carrying cable, and the fiber optic is operably connected to a light detector. A plurality of factors are then evaluated from rotation information from the light detector, by using the first and second channels for analog to digital conversion operably connected with the processor.

A Faraday optical current sensor arrangement for measuring the current through a power line comprises a Faraday optical current sensor (38) having an elongated and substantially cylindrical shape defining a first end and a second end opposite the first end. The Faraday optical current sensor has a first optical conduit (48) extending from the first end and a second optical conduit (48) extending from the second end. Furthermore, the Faraday optical current sensor arrangement comprises a hollow housing (12,14) enveloping the Faraday optical current sensor and fixating the Faraday optical current sensor in a specific measurement position relative to the hollow housing. The hollow housing defines a channel for accommodating the Faraday optical current sensor and the first and second optical conduits and an opening (15) for communicating with the channel. The hollow housing includes a holder (16) for fixating the power line and the hollow housing relative to one another in a juxtaposed position and positioning the Faraday optical current sensor in a specific measuring position relative to the power line.

The invention discloses a thin film type all-fiber current transformer with temperature compensation, and belongs to the technical field of optical current sensors. The problem that a fiber current transformer is likely to be influenced by temperature and vibration, and measurement accuracy is low is solved. According to the thin film type all-fiber current transformer, light emitted by a light source passes through a circulator, a first polarization-maintaining fiber coupler and a Y-waveguide in sequence, the Y-waveguide outputs two paths of light, one path of light passes through a welding branch, rotates by 90 degrees and enters a second polarization-maintaining fiber coupler, the other path of light passes through a compensating coil and enters the second polarization-maintaining fiber coupler, the two paths of light are coupled into one path to be input into a 1/4 wave plate by the second polarization-maintaining fiber coupler, the 1/4 wave plate outputs left rotating light and right rotating light, a Faraday effect happens in a sensor fiber, and then the left rotating light and the right rotating light return to the first polarization-maintaining fiber coupler. In the return process, the original light returned through the welding branch is input into the compensating coil, the other path of light is input into a processing module through the welding branch and the first polarization-maintaining fiber coupler, and the processing module processes the input light to obtain a current value to be measured. The thin film type all-fiber current transformer is used for measuring the current value.

This present inversion provides a digital closed-loop fiber optical current sensor. The modulation signal of the optical wave “phase modulator” of the fiber optical current sensor system is modulation square wave, signal processing system extracts any harmonic wave of the photoelectric converter output modulation square waves, and extracts the measured current information from it. The preamplifier of signal processing system is transimpedance amplifier TIA, the bandwidth is extracted 1/650 instantaneous amplitude square wave directly from the modulation square wave (existing), thus the thermal noise of the preamplifier output and shot noise level is reduced to the existing technology of below 1/650; the current-voltage gain of transimpedance amplifier TIA does not depend on the feedback network resistance, thus it can have high current-voltage conversion gain and use low resistance in the feedback network TIA at the same time. So it can reduce resistance thermal noise to negligible that is accounted for a large proportion of TIA output noise.

The ivnention discloses a current sensor based on optical sensing and a corresponding temperature sensor. The current sensor comprises: a light source, a first transmission fiber, an optical current sensor probe comprising a beam shifter, a Faraday material, an output beam shifter, a second transmission fiber, an optical detection unit and a measurement module. According to the invention, a polarization insensitive current and magnetic sensor and a system thereof adopting active temperature compensation can ensure sensing precision, measurement range and stability of the optical fiber current sensor when sensing the circuit.

The invention relates to a power system relay protection device, in particular to a differential protection device based on optics current sensors to solve the problem that the power loss of a carrier optical signal output by the optics current sensor in cascading is serious. The first optics current sensor and the second optics current sensor are arranged at the two ends of a protection section, a light source is connected with the incidence end of a multimode optical fiber beam splitter through multimode optical fiber, the output end of the multimode optical fiber beam splitter is connected with the incidence end of the first optics current sensor and the incidence end of the second optics current sensor through multimode optical fiber, the emitting end of the first optics current sensor and the emitting end of the second optics current sensor are respectively connected with the incidence end of the multimode optical fiber beam splitter through multimode optical fiber, and the emitting end of the multimode optical fiber beam splitter is connected with the input end of an optical signal processing unit through multimode optical fiber.

The invention relates to an optical current sensor and a high-frequency signal measurement system. The optical current sensor comprises an optical sensing part, a polarization maintaining fiber, an insulator and a demodulation module. The optical sensing part, the polarization maintaining fiber and the demodulation module are connected in sequence. The optical sensing part is supported by the insulator. The polarization maintaining fiber locates in an inner cavity of the insulator. The optical sensing part comprises a first sensing fiber ring, a second sensing fiber ring, a first wave plate, a first reflector, a second wave plate, a second reflector and a support, wherein the first wave plate, the first reflector, the second wave plate, the second reflector and the support are all made of nonmetal material. The first sensing fiber ring and the second sensing fiber ring are opposite in current direction. The demodulation module outputs two linearly-polarized beams passing the polarization maintaining fiber and the optical sensing part, the linearly-polarized beams carrying measured current information are returned and received by the polarization maintaining fiber, the beams are operated on the basis of differential induction, and measured current is obtained. The optical current sensor is capable of measuring high-frequency signals, and measurement is higher in accuracy and reliability.

A two-way transmission optical current sensor relates to a sensor, for solving the problems of difficult packaging and weak environmental tolerance of one in and two out optical path structure of the prior optical current sensor. The optical current sensor comprises an optical sensor, three couplers, a light source, a first detector and a second detector. The first coupler has a first port connected with an output end of the light source, a second port connected with a second port of the second coupler, and a third port connected with a second port of the third coupler. The second coupler has a first port connected with one input/output end of the optical sensor, and the third coupler has a first port connected with the other input/output end of the optical sensor. The second coupler has a third port connected with an input end of the first detector, and the third coupler has a third port connected with an input end of the second detector. The invention is used for measuring currents, can bidirectionally transmit optical signals, is easy to package, and has strong tolerance to environmental change.

The invention discloses a modulation type optical current transducer and a method thereof for measuring alternating and direct current in the technical field of high-voltage circuit current measurement of electric power systems. The current transducer comprises an intelligent modulation light source, a front light splitter, a forward photoelectric converter, a magneto-optical sensing circuit, a backward photoelectric converter and an intelligent photoelectric demodulator, wherein light emitted by the intelligent modulation light source is divided into two beams of light through the front light splitter, one beam of light passes through the magneto-optical sensing circuit and is introduced into the backward photoelectric converter, while the other beam of light is connected to the forward photoelectric converter; electric signals of the backward photoelectric converter and the forward photoelectric converter are input into the intelligent photoelectric demodulator; and a feedback photoelectric signal can be input into the intelligent modulation light source by the intelligent photoelectric demodulator. By utilizing the modulation type optical current transducer, the influences of environmental temperature, unstable light source output and other factors are overcome, and the measurement accuracy of the optical current transducer is improved.

An optical sensor assembly, for installation on a current carrying cable, senses the current in the cable and provides an electrical output indicating the current. To sense the current, a magnetic concentrator is placed in close proximity to the cable and creates a magnetic field representing current in the cable. An optical current sensor, within the created magnetic field, exposes a beam of polarized light to the magnetic field. The beam of polarized light is rotated thereby, by Faraday effect, according to the current in the cable. The amount of rotation is analyzed and converted to electrical signals to portray the current in the cable. The electrical signals may be processed, evaluated and analyzed to provide one or more of several elements of quality of the current in the cable.

A light detecting apparatus includes: a first photoelectric conversion element unit (110) and a second photoelectric conversion element unit(120) each of which converts input light to an electric current and output it; an optical current transducer unit (100) for outputting, as a detected current, a differential current between an electric current outputted by the first photoelectric conversion element unit and an electric current outputted by the second photoelectric conversion element unit; and a first current/voltage converting unit (200) for amplifying the detected current outputted from the optical current transducer unit, converting it to a voltage signal, and outputting the voltage signal.