CN109375138B - Light path fault self-diagnosis alarm device and method for optical fiber current transformer - Google Patents
Light path fault self-diagnosis alarm device and method for optical fiber current transformer Download PDFInfo
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Abstract
The invention discloses a light path fault self-diagnosis warning device and a light path fault self-diagnosis warning method for an optical fiber current transformer. The device comprises a first coupler, wherein a first port, a second port, a third port and a fourth port of the first coupler are respectively and correspondingly connected with a light source, a first detector, a Y waveguide and a second detector; the Y waveguide is also connected with a third detector and a lambda/4 wave plate through a second coupler respectively, and the first detector, the second detector and the third detector are all connected with a modulation-demodulation module; the light which is split by the second coupler and enters the lambda/4 wave plate is converted into two beams of circularly polarized light, then directly enters the sensitive optical fiber, is transmitted to the reflector by the sensitive optical fiber and then reflected, then sequentially passes through the sensitive optical fiber and the lambda/4 wave plate, returns to the Y waveguide to form interference light, the interference light is sequentially transmitted to the modulation and demodulation module by the first coupler and the first detector, and the modulation and demodulation module is connected with the Y waveguide to realize closed-loop control.
Description
Technical Field
The invention belongs to the field of electric power, and particularly relates to a light path fault self-diagnosis warning device and method for an optical fiber current transformer.
Background
The optical fiber current transformer serving as novel current measuring equipment has the advantages of being simple in insulation, small in size, safe, reliable, digital, capable of measuring, measuring and protecting integrally and the like, and is key equipment for intelligent substation construction. The development of the optical fiber current transformer is started earlier abroad, and the network hanging operation is carried out at the earliest time. The development and the start of the optical fiber current transformer in China are late, but the development is rapid, the technical level is advanced greatly, in recent years, particularly under the traction of the construction requirement of an intelligent transformer substation, the market requirement of the optical fiber current transformer is continuously increased, and the optical fiber current transformer is applied to the intelligent transformer substation in small and medium batches. The optical fiber current transformer represents the development direction of the transformer industry, and the optical fiber current transformer must gradually replace the traditional electromagnetic transformer to become mainstream configuration equipment in the field of power measurement in the future.
The optical fiber current transformer is used as current sensing type current measuring equipment, and the main principle is that the magneto-optic Faraday principle is utilized, namely polarized light deflects in a magnetic field generated by current, and the deflection angle is in direct proportion to the current. The optical fiber current transformer converts phase change caused by current into light intensity change by using a reciprocal light path interference principle, and after a light intensity signal is converted into an electric signal by a photoelectric detector, the electric signal is sampled by an A/D (analog/digital) converter, and sampled data is demodulated to finally obtain current data.
The optical fiber current transformer belongs to optical fiber sensing equipment, and the state of an optical path of the optical fiber current transformer determines the product performance and reliability of the optical fiber current transformer. The intelligent substation has high requirements on the reliability and the intelligent degree of the optical fiber current transformer, and requires that the optical fiber current transformer equipment sends out early warning and maintenance signals when the performance of the optical fiber current transformer equipment is degraded, and can timely perform self-diagnosis and give out warning information when the equipment breaks down, so that the phenomenon that the quality of the equipment breaks down and sends out wrong measurement data to cause misoperation and power failure of a relay protection device at the rear end of a power system is avoided.
In summary, the optical fiber current transformer needs a perfect optical path self-diagnosis function, and the optical path warning function of the existing optical fiber current transformer can basically diagnose an optical path fault, but the fault diagnosis data information is limited, so as to ensure the reliability of equipment, the self-diagnosis design of the optical fiber current transformer is strict, the over-diagnosis condition often occurs, normal equipment is shut down and repaired, and when the optical fiber current transformer has a fault, the optical path fault position of the optical fiber current transformer cannot be accurately determined.
Disclosure of Invention
In order to overcome the defects of the prior art, a first object of the present invention is to provide an optical path fault self-diagnosis warning device for an optical fiber current transformer, which accurately judges an optical path fault by comparing the demodulated light intensity data with corresponding threshold values by using the light intensity at different nodes in the optical path.
The invention discloses a light path fault self-diagnosis warning device for an optical fiber current transformer, which comprises a first coupler, wherein a first port, a second port, a third port and a fourth port of the first coupler are respectively and correspondingly connected with a light source, a first detector, a Y waveguide and a second detector; the Y waveguide is also connected with a third detector and a lambda/4 wave plate through a second coupler respectively, and the first detector, the second detector and the third detector are all connected with a modulation-demodulation module;
the light which is split by the second coupler and enters the lambda/4 wave plate is converted into two beams of circularly polarized light, then directly enters the sensitive optical fiber, is transmitted to the reflector by the sensitive optical fiber and then reflected, then sequentially passes through the sensitive optical fiber and the lambda/4 wave plate, and returns to the Y waveguide to form interference light, the interference light is sequentially transmitted to the modulation and demodulation module by the first coupler and the first detector, and the modulation and demodulation module is connected with the Y waveguide to realize closed-loop control; the modem module configured to:
correspondingly demodulating first light intensity data and second light intensity data according to the direct current quantity and the alternating current quantity in the signal transmitted by the first detector; correspondingly demodulating third light intensity data and fourth light intensity data according to signals transmitted by the second detector and the third detector respectively;
and comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path.
The signal received by the first detector comprises a direct current part and an alternating current part, wherein the direct current light intensity consists of a noise light intensity and an interference light intensity direct current part, and the alternating current part consists of an interference light intensity part related to phase change caused by alternating current.
The second detector is used for receiving the light intensity of the light source after beam splitting through the first coupler;
and the third detector is used for receiving the light intensity split by the second coupler.
The light source is connected with the light source driving refrigeration module, and the light source driving refrigeration module is used for driving the light source to continuously and stably emit light and keeping the temperature of the light source within a certain range.
Further, the first detector, the second detector and the third detector are respectively connected with the modulation and demodulation module through a first A/D conversion module, a second A/D conversion module and a third A/D conversion module; the modulation and demodulation module is connected with the Y waveguide through the D/A conversion module.
The first A/D conversion module, the second A/D conversion module and the third A/D conversion module are used for correspondingly adopting signals transmitted by the first detector, the second detector and the third detector respectively.
Furthermore, the first a/D conversion module, the second a/D conversion module and the third a/D conversion module respectively sample signals transmitted by the first detector, the second detector and the third detector simultaneously within the same modulation amplitude under the control of the corresponding sampling clocks.
Furthermore, the tail fiber at one end of the Y waveguide is welded with the first port of the second coupler by 0 degree, and the tail fiber at the other end of the Y waveguide is welded with the second port of the second coupler by 90 degrees.
Furthermore, a delay line is connected between the second coupler and the lambda/4 wave plate in series and is used for converting the light which is split by the second coupler and enters the lambda/4 wave plate into two beams of circularly polarized light.
Further, the modulation and demodulation module comprises a light path alarm module, which is used for comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path; and
the step wave generation module is used for demodulating the obtained current data according to the alternating current quantity in the signal transmitted by the first detector to generate a step wave signal;
the bias modulation wave generating module is used for generating a bias signal according to the intrinsic frequency of the optical path; and
and the modulation error module is used for producing an error signal according to error data obtained by demodulating the alternating current quantity in the signal transmitted by the first detector.
Furthermore, the modem module further includes a timing control module, which is configured to generate operating clocks of the first a/D conversion module, the second a/D conversion module, the third a/D conversion module, and the D/a conversion module according to the eigenfrequency of the optical path, so as to control the operating timings of the first a/D conversion module, the second a/D conversion module, the third a/D conversion module, and the D/a conversion module.
Furthermore, the step wave generation module, the offset modulation wave generation module and the modulation error module are connected with the D/A conversion module through an adder.
Specifically, the optical fiber current transformer is powered on, and the modulation and demodulation module generates a two-state square wave modulation waveform according to the intrinsic cycle of the light path; voltage modulation is carried out on the light wave of the optical fiber current transformer in an eigenperiod according to the applied modulation waveform, corresponding modulation voltage is applied to the Y waveguide, and the modulation phase difference of the Y waveguide corresponding to 2 eigenmodulation voltages is as follows:
where epsilon is the amount of Y waveguide modulation error,
is pi/2.
Applying an artificial modulation error delta to each modulation sequence in the modulation waveform in alternating periods; after the modulation error quantity delta is artificially applied, the modulation phase difference of the Y waveguide corresponding to 2 intrinsic modulation voltages is as follows:
wherein epsilon is the Y waveguide modulation error quantity, delta is the artificially applied modulation error quantity,
is pi/2;
under the control of a sampling clock, three detector signals are respectively sampled through three paths of A/D conversion in the same modulation amplitude, and the sampling data of a second A/D conversion module and a third A/D conversion module in the three A/D conversion modules are light intensity data of the nodes of the optical paths where the sampling data are located and can be directly utilized; the alternating current part in the sampling data of the first A/D conversion module contains the light power and needs to be demodulated by a specific method, and finally the interference light intensity and the current value are obtained.
The first a/D conversion module needs to sample each modulation sequence in the modulation waveform, and after dc blocking of the dc part, the sampling value is:
(1) when no artificial modulation error is applied, the sampling values in the modulation sequence in the same modulation period are as follows:
therein, ad10Without applying the sampled values of the first modulation sequence in the modulation period of the artificial modulation error, ad20Without applying the sampled values of the second modulation sequence in the modulation period of the artificial modulation error, I0Is the optical power value, epsilon is the Y waveguide modulation error,
is the amount of phase change of the light.
(2) When artificial modulation errors are applied, the sampling values in the modulation sequence in the same modulation period are as follows:
therein, ad11Applying sample values of a first modulation sequence within a modulation period of artificial modulation error, ad21Applying sample values of a second modulation sequence in the modulation period of the artificial modulation error, I0Is the optical power value, epsilon is the Y waveguide modulation error,
is the amount of phase change of the light;
according to the sampling value in the modulation sequence in the same modulation period when no artificial modulation error is applied, calculating a Y waveguide modulation error feedback signal epsilon as follows:
calculating current signal and step wave feedback signal according to sampling value in modulation sequence in the same modulation period when no artificial modulation error is applied
Comprises the following steps:
sampling value ad of the first modulation sequence in the modulation period according to the unapplied artificial modulation error10Applying a sampling value ad of a first modulation sequence within a modulation period of an artificial modulation error11And Y waveguide modulation error ε, optical power value I0Comprises the following steps:
the invention also provides an alarm method of the optical path fault self-diagnosis alarm device based on the fiber current transformer.
The invention relates to an alarm method of a light path fault self-diagnosis alarm device for an optical fiber current transformer, which comprises the following steps:
interference light formed by the Y waveguide is transmitted to the modulation and demodulation module by the first coupler and the first detector in sequence, and the modulation and demodulation module correspondingly demodulates first light intensity data and second light intensity data according to direct current quantity and alternating current quantity in signals transmitted by the first detector;
the modulation and demodulation module correspondingly demodulates third light intensity data and fourth light intensity data according to signals transmitted by the second detector and the third detector respectively;
and the modulation and demodulation module compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path.
Further, the specific process of comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively by the modulation and demodulation module to judge the fault position of the light path is as follows:
when the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, sending out a light path alarm signal, and judging that a fault is located in a light path in front of the first coupler;
when the first light intensity data, the second light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, and the third light intensity data are unchanged, sending a light path alarm signal, and judging that a fault is positioned in a light path between the first coupler and the second coupler;
when the first light intensity data and the second light intensity data are reduced at the same time and are smaller than the corresponding threshold values, and the third light intensity data and the fourth light intensity data are unchanged, sending a light path alarm signal, and judging that the light path fault is positioned in the light path behind the second coupler;
and when the second light intensity data is reduced and is smaller than the corresponding threshold value, and the first light intensity data, the third light intensity data and the fourth light intensity data are not changed, sending a light path alarm signal, and judging that the noise of the light path is increased and the interference signal is reduced.
In the judgment process that the modulation and demodulation module respectively compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds to judge the fault position of the light path, as long as the two light intensity data are smaller than the corresponding thresholds, the light path is considered to have a fault, and the states of the first light intensity data, the third light intensity data and the fourth light intensity data represent the fault position and the fault characteristic of the light path.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention can effectively demodulate the light path interference light intensity, effectively detect the light path sensing light and diagnose the light path fault more accurately;
(2) the invention collects and detects light intensity data of different light path nodes of the light path, so that the light path is more comprehensively diagnosed, and the fault occurrence position is effectively judged;
(3) the invention analyzes and diagnoses the light intensity information of different positions of the light path, can greatly improve the fault diagnosis accuracy and prevent the occurrence of misdiagnosis.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.
FIG. 1 is a schematic structural diagram of an optical path fault self-diagnosis warning device for an optical fiber current transformer according to the present invention;
FIG. 2 is a schematic diagram of the present invention incorporating periodic artificial modulation error square waves.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
Fig. 1 is a schematic structural diagram of an optical path fault self-diagnosis warning device for an optical fiber current transformer of the invention.
As shown in fig. 1, the first port 11, the second port 12, the third port 13 and the fourth port 14 of the first coupler are respectively connected with the light source, the first detector, the Y waveguide and the second detector.
Under the action of the light source driving refrigeration module, light emitted by the light source is split by the first coupler, enters the Y waveguide through the third port 13 of the first coupler, and enters the second detector through the fourth port 14 of the first coupler.
After the light is subjected to phase modulation through the Y waveguide, two linearly polarized light beams are output, wherein one light beam is modulated, and the two linearly polarized light beams enter a second coupler through the Y waveguide:
and the tail fiber at one end of the Y waveguide is fused with the first port of the second coupler by 210 degrees, and the tail fiber at the other end of the Y waveguide is fused with the second port 2290 degrees of the second coupler.
Therefore, the light entering the second coupler is transmitted along the fast axis and the slow axis of the polarization maintaining fiber respectively, after being split by the second coupler, enters the third detector through the fourth port 24 of the second coupler, enters the delay line through the third port 2 of the second coupler, is converted into two beams of circularly polarized light through the lambda/4 wave plate, wherein one beam is levorotatory, the other beam is dextrorotatory, enters the sensitive fiber of the fiber ring for transmission, and the phase difference generated by the two beams of elliptically polarized light under the combined action of the Faraday magneto-optical effect and the measured current is as follows:
wherein N is the winding number of the sensitive optical fiber, V is the fiber Verdet constant, and A is the measured current.
Two beams of elliptically polarized light are transmitted to the reflector to be reflected and then enter the sensitive optical fiber again, the original left-handed light is changed into right-handed light, the original right-handed light is changed into left-handed light, and phase difference is generated under the combined action of Faraday magneto-optical effect and measured current
At this time, the total phase difference becomes
Two beams of elliptically polarized light carrying current information pass through the lambda/4 wave plate againThe light signal is converted into an electric signal by the first detector, the electric signal is sampled by the first A/D conversion module, the digital signal is demodulated according to the applied modulation signal, then the first light intensity data, the second light intensity data and the measured current signal are output, meanwhile, a modulation error signal, a modulation signal and a feedback step wave are generated, and finally, the modulation signal, the step wave and the modulation error signal are superimposed and fed back to the Y waveguide together to complete digital closed-loop control.
The optical fiber current transformer adopts a reciprocal light path, light emitted by a light source enters the three detectors after passing through each device of the light path, wherein the light power entering the second detector and the third detector is direct current light intensity signals, and third light intensity data and fourth light intensity data can be directly obtained after AD sampling.
The signal received by the first detector comprises a direct current part and an alternating current part, wherein the direct current light intensity consists of a noise light intensity and an interference light intensity direct current part, and the alternating current part consists of an interference light intensity part related to phase change caused by alternating current.
The second detector is used for receiving the light intensity of the light source after beam splitting through the first coupler;
and the third detector is used for receiving the light intensity split by the second coupler.
The light source is connected with the light source driving refrigeration module, and the light source driving refrigeration module is used for driving the light source to continuously and stably emit light and keeping the temperature of the light source within a certain range.
The first detector, the second detector and the third detector are respectively connected with the modulation and demodulation module through a first A/D conversion module, a second A/D conversion module and a third A/D conversion module; the modulation and demodulation module is connected with the Y waveguide through the D/A conversion module.
The first A/D conversion module, the second A/D conversion module and the third A/D conversion module are used for correspondingly adopting signals transmitted by the first detector, the second detector and the third detector respectively.
Specifically, the first a/D conversion module, the second a/D conversion module, and the third a/D conversion module respectively sample signals transmitted by the first detector, the second detector, and the third detector simultaneously within the same modulation amplitude under the control of the corresponding sampling clocks.
As shown in fig. 1, the modem module includes an optical path alarm module, which is used to judge the fault location of the optical path according to the comparison between the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with the corresponding threshold values respectively; and
the step wave generation module is used for demodulating the obtained current data according to the alternating current quantity in the signal transmitted by the first detector to generate a step wave signal;
the bias modulation wave generating module is used for generating a bias signal according to the intrinsic frequency of the optical path; and
and the modulation error module is used for producing an error signal according to error data obtained by demodulating the alternating current quantity in the signal transmitted by the first detector.
The modulation and demodulation module further comprises a time sequence control module which is used for respectively generating working clocks of the first A/D conversion module, the second A/D conversion module, the third A/D conversion module and the D/A conversion module according to the eigenfrequency of the optical path so as to control the working operation time sequences of the first A/D conversion module, the second A/D conversion module, the third A/D conversion module and the D/A conversion module.
Furthermore, the step wave generation module, the offset modulation wave generation module and the modulation error module are connected with the D/A conversion module through an adder.
The invention also provides an alarm method based on the optical path fault self-diagnosis alarm device for the optical fiber current transformer shown in the figure 1.
The invention relates to an alarm method of a light path fault self-diagnosis alarm device for an optical fiber current transformer, which comprises the following steps:
interference light formed by the Y waveguide is transmitted to the modulation and demodulation module by the first coupler and the first detector in sequence, and the modulation and demodulation module correspondingly demodulates first light intensity data and second light intensity data according to direct current quantity and alternating current quantity in signals transmitted by the first detector;
the modulation and demodulation module correspondingly demodulates third light intensity data and fourth light intensity data according to signals transmitted by the second detector and the third detector respectively;
and the modulation and demodulation module compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path.
Specifically, the light entering the first detector is interfered light reflected by a sensitive current signal of the sensitive ring, carries more information, and needs to be demodulated by a specific method, which is as follows.
After two linearly polarized light beams are interfered, the two linearly polarized light beams enter a first detector, and the output signal of the first detector is expressed as:
wherein InAs a noise light intensity, I0In order to interfere with the intensity of the light,
in order to apply the modulation,
phase shift due to faraday effect;
to apply a modulating phase difference, the eigenfrequency of the optical path is related, as shown in fig. 2.
The optical fiber current transformer is electrified, and the modulation and demodulation module generates a two-state square wave modulation waveform according to the intrinsic cycle of the light path; voltage modulation is carried out on the light wave of the optical fiber current transformer in an eigenperiod according to the applied modulation waveform, corresponding modulation voltage is applied to the Y waveguide, and the modulation phase difference of the Y waveguide corresponding to the two eigenmodulation voltages is as follows:
where epsilon is the amount of Y waveguide modulation error,
is pi/2.
Applying an artificial modulation error delta to each modulation sequence in the modulation waveform in alternating periods; after the modulation error quantity delta is artificially applied, the modulation phase difference of the Y waveguide corresponding to 2 intrinsic modulation voltages is as follows:
wherein epsilon is the Y waveguide modulation error quantity, delta is the artificially applied modulation error quantity,
is pi/2.
Under the control of a sampling clock, three detector signals are respectively sampled through three paths of A/D conversion in the same modulation amplitude, and the sampling data of a second A/D conversion module and a third A/D conversion module in the three A/D conversion modules are light intensity data of the nodes of the optical paths where the sampling data are located and can be directly utilized; the alternating current part in the sampling data of the first A/D conversion module contains the light power and needs to be demodulated by a specific method, and finally the interference light intensity and the current value are obtained.
The first detector converts the optical signal into an electrical signal, the first A/D conversion module samples the electrical signal, the photoelectric conversion coefficient and the analog-to-digital conversion coefficient of the detector and the first A/D conversion module are ignored, and the sampling data of the first A/D conversion module is as follows:
low-pass filtering is carried out on the sampling data of the first A/D conversion module to obtain an interference light intensity direct current part, wherein the interference light intensity direct current part is the sum of noise light power and interference light power, namely the first light intensity data:
In+I0becoming ad (DC)
And performing blocking processing on the sampling data of the first A/D conversion module to obtain an interference light intensity alternating current part, wherein the interference light intensity alternating current part comprises an interference light intensity signal, an error signal and a current signal. After the blocking, the sampling data of the first A/D conversion module is changed into:
the time sequence control module controls the first A/D conversion module to sample each modulation sequence in the modulation waveform and block the direct current part of the modulation waveform;
due to the fact that
In the minimum quantity, sin (theta) is approximately equal to theta in engineering application, and then:
(1) when no artificial modulation error is applied, the sampling values in the modulation sequence in the same modulation period are as follows:
therein, ad10Without applying the sampled values of the first modulation sequence in the modulation period of the artificial modulation error, ad20Without applying the sampled values of the second modulation sequence in the modulation period of the artificial modulation error, I0Is the optical power value, epsilon is the Y waveguide modulation error,
is the amount of phase change of the light.
(2) When artificial modulation errors are applied, the sampling values in the modulation sequence in the same modulation period are as follows:
therein, ad11Applying sample values of a first modulation sequence within a modulation period of artificial modulation error, ad21Applying sample values of a second modulation sequence in the modulation period of the artificial modulation error, I0Is the optical power value, epsilon is the Y waveguide modulation error,
is the amount of phase change of the light;
according to the sampling value in the modulation sequence in the same modulation period when no artificial modulation error is applied, calculating a Y waveguide modulation error feedback signal epsilon as follows:
calculating current signal and step wave feedback signal according to sampling value in modulation sequence in the same modulation period when no artificial modulation error is applied
Comprises the following steps:
sampling value ad of the first modulation sequence in the modulation period according to the unapplied artificial modulation error10Applying a sampling value ad of a first modulation sequence within a modulation period of an artificial modulation error11And Y waveguide modulation error ε, optical power value I0Comprises the following steps:
in specific implementation, the specific process of comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively by the modulation and demodulation module to determine the fault position of the light path is as follows:
when the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, sending out a light path alarm signal, and judging that a fault is located in a light path in front of the first coupler;
when the first light intensity data, the second light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, and the third light intensity data are unchanged, sending a light path alarm signal, and judging that a fault is positioned in a light path between the first coupler and the second coupler;
when the first light intensity data and the second light intensity data are reduced at the same time and are smaller than the corresponding threshold values, and the third light intensity data and the fourth light intensity data are unchanged, sending a light path alarm signal, and judging that the light path fault is positioned in the light path behind the second coupler;
and when the second light intensity data is reduced and is smaller than the corresponding threshold value, and the first light intensity data, the third light intensity data and the fourth light intensity data are not changed, sending a light path alarm signal, and judging that the noise of the light path is increased and the interference signal is reduced.
In the judgment process that the modulation and demodulation module respectively compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds to judge the fault position of the light path, as long as the two light intensity data are smaller than the corresponding thresholds, the light path is considered to have a fault, and the states of the first light intensity data, the third light intensity data and the fourth light intensity data represent the fault position and the fault characteristic of the light path.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (9)
1. A light path fault self-diagnosis alarm device for an optical fiber current transformer is characterized by comprising a first coupler, wherein a first port, a second port, a third port and a fourth port of the first coupler are respectively and correspondingly connected with a light source, a first detector, a Y waveguide and a second detector; the Y waveguide is also connected with a third detector and a lambda/4 wave plate through a second coupler respectively, and the first detector, the second detector and the third detector are all connected with a modulation-demodulation module;
the light which is split by the second coupler and enters the lambda/4 wave plate is converted into two beams of circularly polarized light, then directly enters the sensitive optical fiber, is transmitted to the reflector by the sensitive optical fiber and then reflected, then sequentially passes through the sensitive optical fiber and the lambda/4 wave plate, and returns to the Y waveguide to form interference light, the interference light is sequentially transmitted to the modulation and demodulation module by the first coupler and the first detector, and the modulation and demodulation module is connected with the Y waveguide to realize closed-loop control; the modem module configured to:
correspondingly demodulating first light intensity data and second light intensity data according to the direct current quantity and the alternating current quantity in the signal transmitted by the first detector; correspondingly demodulating third light intensity data and fourth light intensity data according to signals transmitted by the second detector and the third detector respectively;
comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path;
the modulation and demodulation module correspondingly demodulates first light intensity data and second light intensity data according to the direct current quantity and the alternating current quantity in the signal transmitted by the first detector;
the specific process of comparing the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path is as follows:
when the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, sending out a light path alarm signal, and judging that a fault is located in a light path in front of the first coupler;
when the first light intensity data, the second light intensity data and the fourth light intensity data are simultaneously reduced and are smaller than corresponding threshold values, and the third light intensity data are unchanged, sending a light path alarm signal, and judging that a fault is positioned in a light path between the first coupler and the second coupler;
when the first light intensity data and the second light intensity data are reduced at the same time and are smaller than the corresponding threshold values, and the third light intensity data and the fourth light intensity data are unchanged, sending a light path alarm signal, and judging that the light path fault is positioned in the light path behind the second coupler;
when the second light intensity data is reduced and is smaller than the corresponding threshold value, and the first light intensity data, the third light intensity data and the fourth light intensity data are not changed, a light path warning signal is sent out, and it is judged that the noise of the light path is increased and the interference signal is reduced;
in the judgment process that the modulation and demodulation module respectively compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds to judge the fault position of the light path, as long as the second light intensity data is smaller than the corresponding thresholds, the light path is considered to have a fault, and the states of the first light intensity data, the third light intensity data and the fourth light intensity data represent the fault position and the fault characteristic of the light path.
2. The optical path fault self-diagnosis warning device for the fiber current transformer as claimed in claim 1, wherein the first detector, the second detector and the third detector are respectively connected with the modulation and demodulation module through a first a/D conversion module, a second a/D conversion module and a third a/D conversion module; the modulation and demodulation module is connected with the Y waveguide through the D/A conversion module.
3. The optical path fault self-diagnosis warning device for the fiber current transformer as claimed in claim 2, wherein the first a/D conversion module, the second a/D conversion module and the third a/D conversion module respectively sample the signals transmitted by the first detector, the second detector and the third detector at the same modulation amplitude value at the same time under the control of the corresponding sampling clocks.
4. An optical path fault self-diagnosis and alarm device for a fiber current transformer as claimed in claim 1, wherein the pigtail at one end of the Y waveguide is fused with the first port of the second coupler at 0 °, and the pigtail at the other end of the Y waveguide is fused with the second port of the second coupler at 90 °.
5. The optical path fault self-diagnosis and alarm device for the fiber current transformer as claimed in claim 1, wherein a delay line is further connected in series between the second coupler and the λ/4 wave plate for converting the light split by the second coupler into two beams of circularly polarized light.
6. The optical path fault self-diagnosis warning device for the fiber current transformer as claimed in claim 2, wherein the modem module comprises an optical path warning module for judging the fault position of the optical path according to the comparison of the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding threshold values, respectively; and
the step wave generation module is used for demodulating the obtained current data according to the alternating current quantity in the signal transmitted by the first detector to generate a step wave signal;
the bias modulation wave generating module is used for generating a bias signal according to the intrinsic frequency of the optical path; and
and the modulation error module is used for producing an error signal according to error data obtained by demodulating the alternating current quantity in the signal transmitted by the first detector.
7. The optical path fault self-diagnosis warning device for the fiber current transformer as claimed in claim 6, wherein the modem module further comprises a timing control module for generating operation clocks of the first a/D conversion module, the second a/D conversion module, the third a/D conversion module and the D/a conversion module according to the eigenfrequency of the optical path to control operation timings of the first a/D conversion module, the second a/D conversion module, the third a/D conversion module and the D/a conversion module, respectively.
8. An optical path fault self-diagnosis and alarm device for an optical fiber current transformer as claimed in claim 6, wherein the step wave generating module, the bias modulation wave generating module and the modulation error module are connected to the D/A conversion module through an adder.
9. An alarm method based on the optical path fault self-diagnosis alarm device for the fiber current transformer according to any one of claims 1 to 8, comprising:
interference light formed by the Y waveguide is transmitted to the modulation and demodulation module by the first coupler and the first detector in sequence, and the modulation and demodulation module correspondingly demodulates first light intensity data and second light intensity data according to direct current quantity and alternating current quantity in signals transmitted by the first detector;
the modulation and demodulation module correspondingly demodulates third light intensity data and fourth light intensity data according to signals transmitted by the second detector and the third detector respectively;
and the modulation and demodulation module compares the first light intensity data, the second light intensity data, the third light intensity data and the fourth light intensity data with corresponding thresholds respectively to judge the fault position of the light path.
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|---|---|---|---|---|
| CN109752684B (en) * | 2018-12-25 | 2021-06-11 | 北京航天时代光电科技有限公司 | Photoelectric module reverse testing method and fault diagnosis and judgment method |
| CN111308156A (en) * | 2019-11-14 | 2020-06-19 | 许继集团有限公司 | All-fiber current transformer supporting multipoint light path state monitoring |
| CN110907876B (en) * | 2019-12-06 | 2021-01-15 | 西安交通大学 | Optical fiber current sensor fault diagnosis system and diagnosis method thereof |
| CN112903084B (en) * | 2021-01-22 | 2022-07-19 | 中化学交通建设集团有限公司 | Optical fiber vibration sensing optical path fault diagnosis method and related equipment |
| CN114236210B (en) * | 2021-11-16 | 2024-04-09 | 北京航天时代光电科技有限公司 | Modulation frequency self-adaptive system and method for optical fiber current transformer |
| CN115902755B (en) * | 2023-02-23 | 2023-08-15 | 国网江西省电力有限公司电力科学研究院 | Alarm parameter testing method for all-fiber current transformer |
| CN116243231B (en) * | 2023-05-08 | 2023-09-12 | 国网江西省电力有限公司电力科学研究院 | Current transformer abnormality alarm method and system considering light source power change |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103424607A (en) * | 2013-07-26 | 2013-12-04 | 易能乾元（北京）电力科技有限公司 | Optical current sensor and high-frequency signal measurement system |
| JP2016035543A (en) * | 2014-08-04 | 2016-03-17 | オリンパス株式会社 | Imaging device and method for correcting image blur using the device |
| CN105467188A (en) * | 2014-09-05 | 2016-04-06 | 易能乾元（北京）电力科技有限公司 | All-fiber current sensor adopting segmented light path fault diagnosis |
| US20170317762A1 (en) * | 2015-12-29 | 2017-11-02 | Facebook, Inc. | Coherently-combined multiple apertures |
| CN107328977A (en) * | 2017-07-07 | 2017-11-07 | 刘勇 | The double sampled all-fiber current transformator of patrilineal line of descent with only one son in each generation sense and its method of work |
| CN107422166A (en) * | 2017-08-07 | 2017-12-01 | 北京航天时代光电科技有限公司 | A kind of optical fiber current mutual inductor suppression optical power fluctuation modulation-demo-demodulation method |
| CN108332785A (en) * | 2018-01-31 | 2018-07-27 | 北京航天控制仪器研究所 | A kind of measuring device and method of large-scale optical fiber grating sensor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102354075B (en) * | 2011-06-20 | 2014-06-11 | 深圳职业技术学院 | Phase generator carrier (PGC) digital demodulation method for interferometric fiber optic sensor and device thereof |
-
2018
- 2018-11-06 CN CN201811314341.0A patent/CN109375138B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103424607A (en) * | 2013-07-26 | 2013-12-04 | 易能乾元（北京）电力科技有限公司 | Optical current sensor and high-frequency signal measurement system |
| JP2016035543A (en) * | 2014-08-04 | 2016-03-17 | オリンパス株式会社 | Imaging device and method for correcting image blur using the device |
| CN105467188A (en) * | 2014-09-05 | 2016-04-06 | 易能乾元（北京）电力科技有限公司 | All-fiber current sensor adopting segmented light path fault diagnosis |
| US20170317762A1 (en) * | 2015-12-29 | 2017-11-02 | Facebook, Inc. | Coherently-combined multiple apertures |
| CN107328977A (en) * | 2017-07-07 | 2017-11-07 | 刘勇 | The double sampled all-fiber current transformator of patrilineal line of descent with only one son in each generation sense and its method of work |
| CN107422166A (en) * | 2017-08-07 | 2017-12-01 | 北京航天时代光电科技有限公司 | A kind of optical fiber current mutual inductor suppression optical power fluctuation modulation-demo-demodulation method |
| CN108332785A (en) * | 2018-01-31 | 2018-07-27 | 北京航天控制仪器研究所 | A kind of measuring device and method of large-scale optical fiber grating sensor |
Non-Patent Citations (1)
| Title |
|---|
| 光纤电流互感器光路故障自诊断告警算法;郭金刚等;《电力系统自动化》;20180902;第42卷;第1-3页 * |
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