Electronic current transformer based on wavelength division multiplexing

Abstract

The invention discloses an electronic current transformer based on wavelength division multiplexing, which comprises a Rogowski coil, an acquisition module and a merging unit, in the acquisition module, an acquisition processing unit is connected with the Rogowski coil, and the acquisition processing unit is used for acquiring an output signal of the Rogowski coil and converting the output signal into a first optical signal. And the power supply module is connected with the acquisition processing unit and is used for providing energy for the acquisition processing unit by using the second optical signal. The first wavelength division multiplexer is connected with the acquisition processing unit and the power supply module. The first wavelength division multiplexer is used for combining the first optical signal and the second optical signal. In the merging unit, a second wavelength division multiplexer is connected with the first wavelength division multiplexer through an optical fiber, and the second wavelength division multiplexer is used for separating the first optical signal from the second optical signal. The signal processing unit is used for processing the first optical signal. The energy supply unit is used for providing a second optical signal. According to the mutual inductor, the number of connectors and potential fault points are reduced, and the stability of the mutual inductor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical fiber sensing, and in particular to an electronic current transformer based on wavelength division multiplexing. BACKGROUND

[0002] In order to adapt to the high voltage and large capacity power system brought by the development of modern science and technology and living standards, the accurate and safe measurement technology of current in power system has become the focus of researchers. The traditional measurement equipment is electromagnetic current transformer, which has many shortcomings such as poor frequency response, easy to be interfered by external electromagnetic interference, large volume, poor safety, output analog signal and so on. Electronic current transformer has the advantages of high precision, small volume, light weight, high frequency response and digital output, which meets the needs of the development of power system to digitalization, intelligentization and networking, and becomes an important development trend of future current detection.

[0003] Electronic current transformer combines electromagnetic induction, optical sensing or electronic components (such as Rogowski coil, Hall element) to realize signal conversion, and outputs sensing information through optical fiber and electronic circuit. For data acquisition and output of each point to be measured in electronic current transformer, two optical fibers are equipped, one of which is used as energy supply optical fiber to provide optical energy for high voltage side sensor and electronic component, avoiding the electromagnetic interference problem of traditional cable, and the other is used as data optical fiber to transmit the current sensing information collected at high voltage side to low voltage side photoelectric conversion module and digital processing unit, realizing high and low voltage isolation and anti-electromagnetic interference transmission. However, the use of two optical fibers increases the wiring cost and potential failure risk, which is not easy for system design and maintenance.

[0004] Therefore, it is of great significance to research an electronic current transformer scheme based on wavelength division multiplexing to realize low-cost and compact current measurement, which is convenient for interface and integration with other equipment, and has high research value and practicality. SUMMARY

[0005] The present application provides an electronic current transformer based on wavelength division multiplexing, which can improve the stability of the transformer.

[0006] The embodiment of the present application provides an electronic current transformer based on wavelength division multiplexing, which comprises a Rogowski coil, a collection module and a merging unit. The collection module comprises a collection processing unit, a power supply module and a first wavelength division multiplexer. The collection processing unit is connected with the Rogowski coil, and is used for collecting an output signal of the Rogowski coil and converting the output signal into a first optical signal. The power supply module is connected with the collection processing unit, and is used for providing energy for the collection processing unit by using a second optical signal. The first wavelength division multiplexer is connected with the collection processing unit and the power supply module, and is used for merging the first optical signal and the second optical signal. The merging unit comprises a second wavelength division multiplexer, a signal processing unit and an energy supply unit. The second wavelength division multiplexer is connected with the first wavelength division multiplexer through an optical fiber, and is used for separating the first optical signal and the second optical signal. The signal processing unit is used for processing the first optical signal. The energy supply unit is used for providing the second optical signal.

[0007] In some embodiments, the collection processing unit comprises a collector, a first laser and a control module. The collector is connected with the Rogowski coil, and is used for collecting the output signal and converting the output signal into a digital signal. The first laser is connected with the collector and connected with the first wavelength division multiplexer, and is used for converting the digital signal into the first optical signal and transmitting the first optical signal to the first wavelength division multiplexer. The control module is connected with the collector, and is used for controlling the collector to work.

[0008] In some embodiments, the power supply module comprises a photocell. The photocell is connected with the control module, and is used for storing energy and providing electric energy for the control module.

[0009] In some embodiments, the signal processing unit comprises a photoelectric detector and a signal processing module. The photoelectric detector is connected with the second wavelength division multiplexer, and is used for converting the first optical signal into an electric signal. The signal processing module is connected with the photoelectric detector, and is used for processing the electric signal.

[0010] In some embodiments, the energy supply unit comprises a second laser and a laser power supply. The second laser is connected with the second wavelength division multiplexer, and is used for providing the second optical signal. The laser power supply is connected with the semiconductor laser, and is used for providing energy for the semiconductor laser.

[0011] In some embodiments, the center wavelength of the first optical signal is 850 nm.

[0012] In some embodiments, the center wavelength of the second optical signal is 905 nm.

[0013] In some embodiments, the first laser comprises a VCSEL laser.

[0014] In some embodiments, the second laser comprises a semiconductor laser.

[0015] In some embodiments, the optical fiber comprises a multimode optical fiber.

[0016] The electronic current transformer based on wavelength division multiplexing provided by the embodiment of the application comprises a Rogowski coil, a collection module and a merging unit. The collection module comprises a collection processing unit, a power supply module and a first wavelength division multiplexer. The collection processing unit is connected with the Rogowski coil, and is used to collect an output signal of the Rogowski coil and convert the output signal into a first optical signal. The power supply module is connected with the collection processing unit, and is used to provide energy for the collection processing unit by using a second optical signal. The first wavelength division multiplexer is connected with the collection processing unit and the power supply module, and is used to merge the first optical signal and the second optical signal. The merging unit comprises a second wavelength division multiplexer, a signal processing unit and an energy supply unit. The second wavelength division multiplexer is connected with the first wavelength division multiplexer through an optical fiber, and is used to separate the first optical signal and the second optical signal. The signal processing unit is used to process the first optical signal. The energy supply unit is used to provide the second optical signal. In the electronic current transformer of the application, the originally separate optical fiber for energy supply and the optical fiber for data transmission are merged into one optical fiber through wavelength division multiplexing, so that the structure is more compact, the number of connectors and potential failure points are reduced, and the stability of the transformer is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, hereinafter, a brief introduction will be given to the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Fig. 1 The structure diagram of the electronic current transformer in the embodiment of the application;

[0019] Fig. 2 The structure diagram of the collection module in the embodiment of the application;

[0020] Fig. 3 The structure diagram of the merging unit in the embodiment of the application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the application more clear, the application will be further described in detail in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0022] ReferenceFigs. 1-3 The embodiment of the present application provides an electronic current transformer based on wavelength division multiplexing, which comprises a Rogowski coil 2, a collection module 3 and a merging unit 5.

[0023] The Rogowski coil 2 is used for sensing the direct current wire 1 and obtaining current sensing data. The Rogowski coil 2 is wrapped around the outer periphery of the direct current wire 1. The Rogowski coil 2 is a hollow solenoid wound on a non-magnetic skeleton, has no core and will not be saturated, has good linearity and frequency characteristics and is suitable for the measurement of harmonic currents, and the output signal of the Rogowski coil 2 has the following relationship with the measured current i:

[0024]

[0025] In the formula, μ0 is the vacuum permeability, n is the coil turn density, S is the coil cross-sectional area, and f is the frequency of the harmonic current. The size of each harmonic current can be obtained according to the output signal of the Rogowski coil 2 at different frequencies.

[0026] The Rogowski coil 2 has no core, and its performance is easily affected by interference factors such as temperature and external magnetic field. The influence of interference can be greatly reduced by adopting appropriate winding techniques (equal ampere-turn and back winding techniques).

[0027] The collection module 3 is arranged on the high-voltage side. The collection module 3 comprises a collection processing unit, a power supply module and a first wavelength division multiplexer 8. The collection processing unit is connected with the Rogowski coil 2, and the collection processing unit is used for collecting the output signal of the Rogowski coil 2 and converting the output signal into a first optical signal. The power supply module is connected with the collection processing unit, and the power supply module is used for providing energy for the collection processing unit by using a second optical signal. The first wavelength division multiplexer 8 is connected with the collection processing unit and the power supply module, and the first wavelength division multiplexer 8 is used for merging the first optical signal and the second optical signal, so that the first optical signal and the second optical signal are multiplexed in one optical fiber 4.

[0028] The collection processing unit comprises a collector 6, a first laser 7 and a control module 9. The collector 6 is connected with the Rogowski coil 2, and the collector 6 is used for collecting the output signal and converting the output signal into a digital signal. The first laser 7 is connected with the collector 6 and connected with the first wavelength division multiplexer 8, and the first laser 7 is used for converting the digital signal into the first optical signal and transmitting the first optical signal to the first wavelength division multiplexer 8. The control module 9 is connected with the collector 6, and the control module 9 is used for controlling the collector 6 to work. The first laser 7 comprises a VCSEL laser.

[0029] The power supply module comprises a photocell 10. The photocell 10 is connected with the control module 9, and the photocell 10 is used for storing energy and providing electric energy for the control module 9.

[0030] The center wavelength of the first optical signal is 850 nm.

[0031] The center wavelength of the second optical signal is 905nm.

[0032] The merging unit 5 is arranged at the low-voltage side. The merging unit 5 comprises a second wavelength division multiplexer 11, a signal processing unit and a power supply unit. The second wavelength division multiplexer 11 is connected with the first wavelength division multiplexer 8 through an optical fiber 4, and the second wavelength division multiplexer 11 is used for separating the first optical signal and the second optical signal. The signal processing unit is used for processing the first optical signal. The power supply unit is used for providing the second optical signal.

[0033] The signal processing unit comprises a photodetector 12 and a signal processing module 13. The photodetector 12 is connected with the second wavelength division multiplexer 11, and the photodetector 12 is used for converting the first optical signal into an electrical signal. The signal processing module 13 is connected with the photodetector 12, and the photodetector 12 is used for processing the electrical signal.

[0034] The power supply unit comprises a second laser 14 and a laser power supply 15. The second laser 14 is connected with the second wavelength division multiplexer 11, and the second laser 14 is used for providing the second optical signal. The laser power supply 15 is connected with the semiconductor laser, and the laser power supply 15 is used for providing energy for the semiconductor laser. The second laser 14 comprises a semiconductor laser.

[0035] The optical fiber 4 is used for realizing the transmission of optical energy and data. The optical fiber 4 comprises a multimode optical fiber 4.

[0036] As can be seen from the above, in the electronic current transformer, the energy required by the collector 6 is provided by the second laser 14. Specifically, the light with the center wavelength of 905nm emitted by the semiconductor laser is transmitted to the photocell 10 through the second wavelength division multiplexer 11, the optical fiber 4 and the first wavelength division multiplexer 8, and the energy is stored in the photocell 10, and then the energy is provided for the collector 6 after being controlled by the control module 9. In addition, the Rogowski coil 2 converts the harmonic current carried by the primary direct current into a voltage signal, the collector 6 converts the signal into a digital signal, and the first laser 7 sends the digital signal to the low-voltage side. The center wavelength of the optical signal sent by the first laser 7 is 850nm, the optical signal is multiplexed to the optical fiber 4 through the first wavelength division multiplexer 8, and then the optical signal is demultiplexed to the photodetector 12 through the second wavelength division multiplexer 11, so as to realize the conversion from the optical signal to the electrical signal. The signal processing module 13 processes the sensing information in the data electrical signal, so as to realize the monitoring of the current. In the above process, the light with the center wavelength of 850nm and 905nm is transmitted in the same optical fiber 4 through the first wavelength division multiplexer 8 and the second wavelength division multiplexer 11.

[0037] Compared with the existing electronic current transformer, the electronic current transformer has the following advantages:

[0038] One, the originally separate optical fiber for energy supply and optical fiber for data transmission are combined into one optical fiber through wavelength division multiplexing, realizing the functions of energy supply and data transmission, making the structure more compact, simple and reliable, and easy to integrate.

[0039] Two, a single optical fiber replaces the double fiber structure, reducing the number of connectors and potential failure points, improving the stability of the mutual inductor, and realizing stable and reliable measurement of the current.

[0040] Three, the first and second wavelength division multiplexers can expand the system capacity by increasing the wavelength channels, and can reserve other wavelength segments for state monitoring or temperature compensation. By adding other wavelength segments of reflective gratings in the sensing channel, the drift amount of the reflected wavelength is monitored to detect the system temperature or other parameters, so as to adjust the working state of the system to meet the requirements of smart grid for multifunctional integration.

[0041] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components; in the description of the present application, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation of the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0042] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electronic current transformer based on wavelength division multiplexing, characterized in that, include: Rogowski coil; The acquisition module includes an acquisition and processing unit, a power supply module, and a first wavelength division multiplexer; The acquisition and processing unit is connected to the Rogowski coil, and the acquisition and processing unit is used to acquire the output signal of the Rogowski coil and convert the output signal into a first optical signal; the power supply module is connected to the acquisition and processing unit, and the power supply module is used to provide energy to the acquisition and processing unit using a second optical signal; the first wavelength division multiplexer is connected to the acquisition and processing unit and the power supply module, and the first wavelength division multiplexer is used to combine the first optical signal and the second optical signal; The merging unit includes a second wavelength division multiplexer, a signal processing unit, and a power supply unit; the second wavelength division multiplexer is connected to the first wavelength division multiplexer via an optical fiber, and the second wavelength division multiplexer is used to separate the first optical signal and the second optical signal; the signal processing unit is used to process the first optical signal; The power supply unit is used to provide the second optical signal.

2. The electronic current transformer as described in claim 1, characterized in that, The acquisition and processing unit includes: A data acquisition unit, connected to the Rogowski coil, is used to acquire the output signal and convert the output signal into a digital signal; A first laser is connected to the collector and to the first wavelength division multiplexer. The first laser is used to convert the digital signal into the first optical signal and transmit the first optical signal to the first wavelength division multiplexer. A control module is connected to the data collector, and the control module is used to control the operation of the data collector.

3. The electronic current transformer as described in claim 2, characterized in that, The power supply module includes: A photovoltaic cell is connected to the control module. The photovoltaic cell is used to store energy and provide power to the control module.

4. The electronic current transformer as described in claim 1, characterized in that, The signal processing unit includes: A photodetector is connected to the second wavelength division multiplexer, and the photodetector is used to convert the first optical signal into an electrical signal; A signal processing module is connected to the photodetector, which is used to process the electrical signal.

5. The electronic current transformer as described in claim 4, characterized in that, The power supply unit includes: A second laser is connected to the second wavelength division multiplexer, and the second laser is used to provide the second optical signal; A laser power supply, connected to the semiconductor laser, is used to provide energy to the semiconductor laser.

6. The electronic current transformer as described in claim 1, characterized in that, The center wavelength of the first optical signal is 850nm.

7. The electronic current transformer as described in claim 1, characterized in that, The center wavelength of the second optical signal is 905nm.

8. The electronic current transformer as described in claim 1, characterized in that, The first laser includes a VCSEL laser.

9. The electronic current transformer as described in claim 1, characterized in that, The second laser includes a semiconductor laser.

10. The electronic current transformer as described in claim 1, characterized in that, The optical fiber includes multimode optical fiber.

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