CN108776319B - Optical fiber current transformer data accuracy self-diagnosis method and system - Google Patents
Optical fiber current transformer data accuracy self-diagnosis method and system Download PDFInfo
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Abstract
The invention discloses a self-diagnosis method and a self-diagnosis system for data accuracy of an optical fiber current transformer, wherein the method comprises the following steps: acquiring a sensing signal of the optical fiber current transformer by using a detector; outputting the sensing signals to a multi-channel for collection, and performing difference analysis on a plurality of output signals output by the multi-channel to obtain a difference analysis result; matching waveforms of a plurality of output signals output by the multi-channel with preset standard waveforms to obtain matching results; and judging the data accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
Description
Technical Field
The invention relates to the technical field of smart power grids, in particular to a data accuracy self-diagnosis method and system for an optical fiber current transformer.
Background
The optical fiber current transformer is a novel passive electronic transformer, is based on an optical fiber technology, adopts non-intrusive measurement to take out the sensitive state quantity in an optical signal form, and has the following technical advantages: strong anti-interference ability, high measuring precision, wide frequency domain measuring performance, small volume, light weight, easy transmission and networking, and can be conveniently applied to microcomputer protection and other electronic devices.
The fault self-diagnosis is also an important characteristic of the intellectualization of the measurement mode of the all-fiber current transformer, the self state can be conveniently checked, the automatic alarm can be realized under the fault condition, and the misoperation of rear-end protection equipment is avoided. In order to prevent acquisition errors of the electronic transformer and errors of an analog-digital processing unit, the intelligent substation relay protection technical specification requires that two independent sampling systems are used for acquiring in the electronic transformer, a double AD system is adopted for connecting each sampling system into an MU, and two digital sampling values output by each MU enter a set of protection device through the same channel so as to meet the requirement of duplicate protection on mutual complete independence. This means that two protection sensor elements should be configured in each set of electronic transformer, each sensor element is collected by two independent sampling systems (dual AD systems), and data of the two sampling systems are output to the MU through the same channel.
The prior art provides various double-channel data acquisition design schemes for an optical fiber current transformer. A design idea is that two paths of sensing optical fibers are adopted to independently acquire primary current signals, each sensing loop is provided with an AD acquisition system, and finally, a signal processing unit FPGA is accessed simultaneously. Although the scheme improves the reliability of the system, the cost is too high, and the popularization and the use are not facilitated.
The other idea is to simultaneously acquire the output voltage signals of the detector through two paths of AD and then send the signals into an FPGA serving as a signal processing unit for processing. The method gives consideration to cost and reliability, but for a sensor prototype with finished hardware design, the original acquisition module must be replaced to realize the double-path data acquisition function, and the method is not beneficial to the later-stage upgrading of the operation prototype installed on an engineering case.
In addition, a design idea based on double AD and double FPGA is adopted, the scheme has higher cost, the circuit power consumption is increased, the internal temperature rise of the acquisition module is indirectly promoted, the influence of the internal temperature rise on the long-term reliability of the sensor is multifactorial, and the comprehensive measurement is required.
Therefore, a technique is required to realize self-diagnosis of the data accuracy of the fiber optic current transformer.
Disclosure of Invention
The technical scheme of the invention provides a self-diagnosis method and a self-diagnosis system for data accuracy of an optical fiber current transformer, which aim to solve the problem of judging the data acquisition accuracy of the optical fiber current transformer.
In order to solve the above problem, the present invention provides a data accuracy self-diagnosis method for an optical fiber current transformer, the method comprising:
acquiring a sensing signal of the optical fiber current transformer by using a detector;
outputting the sensing signals to a multi-channel for collection, and performing difference analysis on a plurality of output signals output by the multi-channel to obtain a difference analysis result;
matching waveforms of a plurality of output signals output by the multi-channel with preset standard waveforms to obtain matching results;
and judging the data acquisition accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
Preferably, the performing the difference analysis on the plurality of output signals output through the multipath channel includes:
and performing difference analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA.
Preferably, the performing the difference analysis on the plurality of output signals output through the multipath channel includes:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and performing difference value analysis on the output signals output by the multi-channel by using the CPU.
Preferably, the acquisition signal is a comb wave having characteristic parameters.
Preferably, the matching of the waveforms of the plurality of output signals output through the multipath channel with a preset standard waveform includes:
extracting and identifying the waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by a parameter, and perform signal extraction on the characteristic information of the output signals;
and the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of the output signals to carry out template matching judgment.
Preferably, the matching of the waveforms of the plurality of output signals output through the multiple channels with a preset standard waveform includes:
and matching the waveforms of the plurality of output signals output by the multipath channel with preset standard waveforms by using a signal processing unit FPGA.
Preferably, the matching of the waveforms of the plurality of output signals output through the multiple channels with a preset standard waveform includes:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and matching the waveforms of the output signals output by the multi-channel with preset standard waveforms by using the CPU.
Preferably, the difference analysis result and the matching result are output in a transmission frame format FT 3.
Based on another aspect of the present invention, there is provided a data accuracy self-diagnosis system for an optical fiber current transformer, the system comprising:
the acquisition unit acquires a sensing signal of the optical fiber current transformer by using the detector;
the first data analysis unit is used for outputting the sensing signals to a multi-channel for collection, and performing difference analysis on a plurality of output signals output by the multi-channel to obtain a difference analysis result;
the second data analysis unit is used for matching the waveforms of the output signals output by the multi-channel with preset standard waveforms to obtain matching results;
and the judging unit is used for judging the data acquisition accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
Preferably, the first data analysis unit is configured to perform difference analysis on a plurality of output signals output through the multiple channels, and includes:
and performing difference analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA.
Preferably, the first data analysis unit is configured to perform a difference analysis on a plurality of output signals output through the multiple channels, and includes:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and performing difference value analysis on the output signals output by the multi-channel by using the CPU.
Preferably, the acquisition signal is a comb wave having characteristic parameters.
Preferably, the second data analysis unit is configured to match waveforms of a plurality of output signals output through the multiple channels with a preset standard waveform, and includes:
extracting and identifying the waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by a parameter, and perform signal extraction on the characteristic information of the output signals;
and the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of the output signals to carry out template matching judgment.
Preferably, the second data analysis unit is configured to match waveforms of a plurality of output signals output through the multiple channels with a preset standard waveform, and includes:
and matching the waveforms of the plurality of output signals output by the multipath channel with preset standard waveforms by using a signal processing unit FPGA.
Preferably, the second data analysis unit is configured to match waveforms of a plurality of output signals output through the multiple channels with a preset standard waveform, and includes:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and matching the waveforms of the output signals output by the multi-channel with preset standard waveforms by using the CPU.
Preferably, the apparatus further comprises an output unit, configured to output the difference analysis result and the matching result in a transmission frame format FT 3.
The technical scheme of the invention provides a method and a system for self-diagnosing the data accuracy of an optical fiber current transformer, and realizes the technology of self-diagnosing the state of the optical fiber current transformer. The technical scheme of the invention realizes the effect equivalent to that of double AD acquisition in the technical specification of intelligent substation relay protection on the premise of not increasing hardware cost, and can also be realized on the hardware scheme of double AD acquisition.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
FIG. 1 is a flow chart of a method for self-diagnosing data accuracy of an optical fiber current transformer according to a preferred embodiment of the present invention;
FIG. 2 is a schematic diagram of a fiber optic current transformer data accuracy self-diagnosis in accordance with a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a principle for determining data acquisition accuracy of a fiber optic current transformer according to a preferred embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a principle for determining data acquisition accuracy of a fiber optic current transformer according to a preferred embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a principle for determining data acquisition accuracy of a fiber optic current transformer according to a preferred embodiment of the present invention;
FIG. 6 is a schematic diagram of a matched template signal according to a preferred embodiment of the present invention;
FIG. 7 is a diagram illustrating comparison of matching templates when the input signal is a comb according to the preferred embodiment of the present invention;
FIG. 8 is a diagram illustrating comparison of matching templates when the input signal is a square wave according to the preferred embodiment of the present invention;
FIG. 9 is a diagram illustrating comparison of matching templates when the input signal is a sine wave according to the preferred embodiment of the present invention;
FIG. 10 is a diagram illustrating comparison of matching templates when an input signal is an anomalous wave according to a preferred embodiment of the present invention;
FIG. 11 is a schematic illustration of the matching distances of different keyed waveform signals in accordance with a preferred embodiment of the present invention;
FIG. 12 is a schematic diagram of the matching distance of a 2-octave comb signal according to the preferred embodiment of the invention;
FIG. 13 is a schematic diagram of matching distances of a 3-octave comb signal according to a preferred embodiment of the present invention;
FIG. 14 is a diagram illustrating matching distances of a 0.5 frequency-doubled comb signal according to a preferred embodiment of the present invention;
FIG. 15 is a diagram illustrating matching distances corresponding to combs of different frequencies according to a preferred embodiment of the present invention; and
fig. 16 is a configuration diagram of a data accuracy self-diagnosis system of the optical fiber current transformer according to the preferred embodiment of the present invention.
Detailed Description
Example embodiments of the present invention will now be described with reference to the accompanying drawings, however, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, which are provided for a complete and complete disclosure of the invention and to fully convey the scope of the invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same unit/element is denoted by the same reference numeral.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their context in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a flowchart of a method for determining data acquisition accuracy of a fiber optic current transformer according to a preferred embodiment of the present invention. As shown in fig. 1, a method for self-diagnosing data accuracy of an optical fiber current transformer includes:
preferably, in step 101: and acquiring a sensing signal of the optical fiber current transformer by using a detector.
Preferably, at step 102: and outputting the sensing signals to the multipath channel for collection, and performing difference analysis on the output signals output by the multipath channel to obtain a difference analysis result. Preferably, the difference analysis is performed on a plurality of output signals output through the plurality of channels, including: and performing difference value analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA. Preferably, the difference analysis is performed on a plurality of output signals output through the plurality of channels, including: and the signal processing unit FPGA is used for transmitting the output signals to the central processing unit CPU, and the central processing unit CPU is used for carrying out difference value analysis on the output signals output by the multipath channel.
Preferably, in step 103: and matching the waveforms of the output signals output by the multipath channel with preset standard waveforms to obtain a matching result.
Preferably, the acquisition signal is a comb with characteristic parameters.
Preferably, matching waveforms of the plurality of output signals output through the multiplexer with a preset standard waveform includes: extracting and identifying waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by parameters and to extract characteristic information of the output signals; the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of a plurality of output signals to carry out template matching judgment.
Preferably, matching waveforms of the plurality of output signals output through the multiplexer with a preset standard waveform includes: and matching the waveforms of the output signals output by the multipath channel with preset standard waveforms by using the FPGA.
Preferably, matching waveforms of the plurality of output signals output through the multipath with a preset standard waveform includes: and the signal processing unit FPGA is used for transmitting the output signals to the central processing unit CPU, and the central processing unit CPU is used for matching the waveforms of the output signals output by the multipath channel with the preset standard waveforms.
Preferably, at step 104: and judging the data acquisition accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
Preferably, the difference analysis result and the matching result are output in a transmission frame format FT 3.
Fig. 16 is a system configuration diagram for judging data acquisition accuracy of the fiber optic current transformer according to the preferred embodiment of the invention. As shown in fig. 16, a data accuracy self-diagnosis system of a fiber optic current transformer, the system comprising:
and the acquisition unit 1601 is used for acquiring a sensing signal of the optical fiber current transformer by using a detector.
The first data analysis unit 1602 is configured to output the sensing signal to the multiple paths for collection, perform difference analysis on multiple output signals output by the multiple paths, and obtain a difference analysis result. Preferably, the first data analysis unit 1602 is configured to perform difference analysis on a plurality of output signals output through the multiple channels, and includes: and performing difference value analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA.
Preferably, the first data analysis unit 1602 is configured to perform a difference analysis on a plurality of output signals output through the multiple channels, and includes: and the signal processing unit FPGA is used for transmitting the output signals to the central processing unit CPU, and the central processing unit CPU is used for carrying out difference value analysis on the output signals output by the multipath channel.
The second data analysis unit 1603 is configured to match waveforms of the multiple output signals output via the multiple channels with a preset standard waveform to obtain a matching result. 12. The system of claim 9, wherein the acquired signal is a comb having characteristic parameters.
Preferably, the second data analysis unit 1603 is configured to match waveforms of the plurality of output signals output via the multi-path with a preset standard waveform, and includes: extracting and identifying waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by parameters and to extract characteristic information of the output signals; the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of a plurality of output signals to carry out template matching judgment.
Preferably, the second data analysis unit 1603 is configured to match waveforms of the plurality of output signals output via the multi-path with a preset standard waveform, and includes: and matching the waveforms of the output signals output by the multipath channel with preset standard waveforms by using the FPGA.
Preferably, the second data analysis unit 1603 is used for matching the waveforms of the plurality of output signals output via the multiple channels with a preset standard waveform, and comprises:
and the signal processing unit FPGA is used for transmitting the output signals to the central processing unit CPU, and the central processing unit CPU is used for matching the waveforms of the output signals output by the multipath channel with the preset standard waveforms.
And a judging unit 1604, configured to judge accuracy of data acquisition of the optical fiber current transformer according to the difference analysis result and the matching result.
Preferably, the device further comprises an output unit, configured to output the difference analysis result and the matching result in a transmission frame format FT 3.
The following illustrates embodiments of the invention:
the functional structure block diagram of the all-fiber current transformer is shown in fig. 2, light emitted by a wide-spectrum light source enters an optical module with polarization and phase modulation functions after passing through a coupler (or a circulator), and light beams are changed into two linearly polarized light beams with mutually orthogonal polarization directions and enter an optical fiber delay loop to be transmitted along the X axis and the Y axis of a polarization-maintaining optical fiber respectively. The linearly polarized light of the two orthogonal modes is changed into left-handed circularly polarized light and right-handed circularly polarized light after passing through a lambda/4 wave plate, and enters the sensing optical fiber ring for transmission. The current transmitted in the current-carrying conducting wire generates a magnetic field, a Faraday magneto-optical effect is generated in the sensing optical fiber, so that the two beams of circularly polarized light generate phase difference, after the two beams of circularly polarized light are reflected at the end surface of the reflector, the polarization modes of the two beams of circularly polarized light are interchanged (namely, the left-handed light is changed into the right-handed light, and the right-handed light is changed into the left-handed light), the two beams of circularly polarized light pass through the sensing optical fiber ring again, and the phase difference generated by the two beams of light is doubled through the Faraday effect. The two beams of light pass through the lambda/4 wave plate again and are recovered into linearly polarized light to return, and interference occurs at the polarizing position. Finally, light carrying non-reciprocal phase difference information generated by the faraday effect is returned to the photodetector by the coupler and converted into an electrical signal. According to the Faraday magneto-optical effect and the ampere loop law, the current transmitted in the current carrying wire is in direct proportion to the phase difference, so that the current value to be measured can be calculated by detecting a light phase difference signal.
The embodiment of the invention is explained by taking two-way data acquisition as an example, the self-diagnosis method for data acquisition in the application is divided into two stages, wherein the first stage is the analysis of the difference result of two-way acquired signals, and the second stage is the prediction diagnosis result of the waveform of the two-way acquired signals. And judging the correctness of the two-way acquired data through the first-stage diagnosis result, and judging the correctness of the working state of the closed-loop detection circuit of the system through the second-stage diagnosis result.
In this application, the first-stage data diagnosis method is: output signals of the detector are acquired by the two data acquisition channels, the two output signals are transmitted to the FPGA for difference operation, and an operation value is used as a primary diagnosis result, or the two output signals are directly transmitted to the CPU by the FPGA, the CPU performs difference operation, and the operation value is uploaded to the FPGA as the primary diagnosis result.
In the present application, the second-level data diagnosis method is: after the two-way output signal is transmitted to the FPGA, because the closed-loop output waveform of the optical fiber current transformer is a specific comb wave, the two-way signal is identified and detected through a waveform matching technology and is compared with a standard waveform signal prestored in the FPGA, so that waveform prediction diagnosis can be realized, or the two-way output signal is transmitted to a CPU from the FPGA and then is identified and detected in the CPU, and the advantage of waveform prediction diagnosis in the CPU is that the workload of development and debugging can be reduced. And judging whether the working states of the AD, the FPGA and other key electronic chips participating in closed-loop detection are stable and correct or not according to the result of the waveform detection, and using the diagnosis information as a secondary diagnosis result.
The waveform matching technology is divided into two steps of extracting and identifying the signal waveform, and the signal extraction can be generally carried out by utilizing a specific characteristic basis function expressed by parameters and expanding the signal according to a certain mathematical rule, for example, by utilizing a Fourier basis function, a wavelet basis function and a linear combination of wavelets, namely 'composite wavelets', to express the characteristic information of the signal. The waveform identification generally adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of signals to carry out template matching judgment.
The waveform matching technique is exemplified in that each waveform has its own shape, but the amplitude of the waveform is different in the case where external conditions are changed (e.g., voltage level, sampling frequency, etc.). As shown in fig. 6 to 10, for each digital waveform W, a vector X containing m elements can be used to represent:
X＝[x 1 x 2 x 3 ......x m-1 x m ] (1)
wherein, the element x i Is the amplitude of a certain point of the waveform, and the time interval between two adjacent elements is equal. After normalization, the vector X can be used as a matching template signal.
Because the optical path eigenfrequency of different optical fiber current transformers is different, and the period of the corresponding comb wave template is also different, the modulation frequency of the system needs to be matched with the optical path eigenfrequency when each set of optical fiber current transformer is installed and debugged, and after the modulation frequency is matched, the period of the corresponding comb wave matching template can be calculated according to the eigenfrequency of the optical path.
Normalizing the input waveform Y:
during the matching process of the waveforms, the distance D between the input waveform vector Y and the waveform template X is defined:
D＝||X-Y|| 2
＝∑(x i -p i )，(i＝1，2…m) (3)
in order to verify the judgment threshold value of D, matching tests are carried out on different input signals as follows, in order to enable the output waveform of the FPGA to complete real-time online self-checking, the calculation of waveform matching is usually completed within each transition time, and the fault can be judged if two times of continuous out-of-tolerance are carried out:
as shown in fig. 11, it is obvious that the matching distance of the comb wave is the minimum and is very easy to identify.
Also a comb signal, the matching results for input waveforms of different frequencies are shown in fig. 12 to 14.
Fig. 15 shows the matching distances of the comb signals with different frequency multiplication numbers, and it can be seen that the matching distance of the normal comb signal is still the minimum.
The method for realizing double-path data acquisition comprises the following steps: two data acquisition channels of the same AD (as shown in fig. 3); 2) Two independently working AD acquisition chips (as shown in fig. 4). In terms of reliability, the first method only adopts 1 AD chip, the second method adopts 2 AD chips, and the system reliability and the cost of the second method are higher assuming that the reliability of the AD chips is the same. However, compared with the original one-way data acquisition scheme, the two-way data acquisition methods improve the system reliability, so that different two-way data acquisition schemes can be flexibly selected according to the reliability requirements of products in actual application.
After the two-path signal completes the waveform matching detection in the CPU, the diagnosis result is transmitted back to the FPGA, and the FPGA packages the data of the two-stage diagnosis result and then encodes and outputs the data in an FT3 format.
Based on the implementation mode of the invention, the technical scheme of multi-path data acquisition and self-diagnosis of the optical fiber current transformer can be further designed, the multi-path acquired signals are compared and operated in the FPGA, the data validity is judged by judging whether the signals belong to 'majority' or 'minority' in all the sampled data, and a certain path of signal in the 'majority' signal is extracted as a main signal to participate in closed-loop detection. The working state of each acquisition channel is diagnosed by checking the correctness of the output waveform of each channel of signal through a waveform matching technology, and a schematic diagram of the working state is shown in fig. 5.
In the application, 3-path data acquisition can be adopted in the design of the multi-path data acquisition and self-diagnosis technology of the optical fiber current transformer, 2 'most' signals are selected as effective signals, self-diagnosis can be realized on the basis of redundancy design, and meanwhile, the fact that the power consumption of a circuit is not too high is guaranteed.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ means, component, etc ]" are to be interpreted openly as referring to at least one instance of said means, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (8)
1. A fiber optic current transformer data accuracy self-diagnostic method, the method comprising:
acquiring a sensing signal of the optical fiber current transformer by using a detector; outputting the sensing signal to a plurality of channels for collection, performing difference analysis on a plurality of output signals output by the plurality of channels, and acquiring a difference analysis result, wherein the difference analysis result comprises:
performing difference value analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA;
matching waveforms of a plurality of output signals output by the multi-channel with preset standard waveforms to obtain matching results;
wherein, the matching of the waveforms of the plurality of output signals output through the multipath channel with the preset standard waveforms includes:
extracting and identifying the waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by parameters, and perform signal extraction on the characteristic information of the output signals;
the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of the output signals to carry out template matching judgment; or
The matching of the waveforms of the plurality of output signals output through the multipath channel with the preset standard waveforms includes:
matching waveforms of a plurality of output signals output by the multi-channel with preset standard waveforms by using a signal processing unit FPGA; or
The matching of the waveforms of the plurality of output signals output through the multipath channel with the preset standard waveforms includes:
the signal processing unit FPGA is used for transmitting the output signals to a central processing unit CPU, and the central processing unit CPU is used for matching the waveforms of the output signals output by the multipath channel with preset standard waveforms;
the matching method comprises the following steps:
for each digital waveform W, it is represented by a vector X containing m elements:
X＝[x 1 x 2 x 3 ...... x m-1 x m ]formula 1
Wherein, the element x i Is the amplitude, x, of a point of the waveform 1 To x m The standard waveform amplitude value sampling sequence is a standard waveform amplitude value sampling sequence, and the time intervals between two adjacent elements in the standard waveform amplitude value sampling sequence are equal; carrying out normalization processing on the vector X, wherein the vector X can be used as a matching template signal;
normalizing the input waveform Y:
during the matching process of the waveforms, the distance D between the input waveform vector Y and the vector X is defined:
D＝||X-Y|| 2
＝Σ(x i -p i ) (i =1,2 \8230m) formula 3
Respectively inputting comb wave signals with different frequency multiplication numbers, and determining the waveform corresponding to the minimum distance as a normal comb wave signal;
and judging the data acquisition accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
2. The method of claim 1, the performing a difference analysis on the plurality of output signals output through the plurality of channels, comprising:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and performing difference value analysis on the output signals output by the multi-channel by using the CPU.
3. The method of claim 1, wherein the acquired signal is a comb having characteristic parameters.
4. The method of claim 1, outputting the difference analysis result and the matching result in a transmission frame format FT 3.
5. A fiber optic current transformer data accuracy self-diagnostic system, the system comprising:
the acquisition unit acquires a sensing signal of the optical fiber current transformer by using the detector;
the first data analysis unit is used for outputting the sensing signals to a plurality of channels for collection, performing difference analysis on a plurality of output signals output by the plurality of channels, and acquiring a difference analysis result, and comprises:
performing difference value analysis on a plurality of output signals output by the multi-channel by using a signal processing unit FPGA;
the second data analysis unit is used for matching the waveforms of the output signals output by the multi-channel with preset standard waveforms to obtain matching results;
the second data analysis unit is further configured to match waveforms of a plurality of output signals output through the multipath channel with a preset standard waveform, and includes:
extracting and identifying the waveforms of the output signals, wherein the signal extraction is to expand the output signals according to a certain mathematical rule by using a specific characteristic basis function expressed by a parameter, and perform signal extraction on the characteristic information of the output signals;
the waveform identification adopts a signal modulation identification algorithm to extract instantaneous characteristic statistical parameters of the output signals to carry out template matching judgment; or
The second data analysis unit is further configured to match waveforms of a plurality of output signals output through the multipath channel with a preset standard waveform, and includes:
matching waveforms of a plurality of output signals output by the multi-channel with preset standard waveforms by using a signal processing unit FPGA; or
The second data analysis unit is further configured to match waveforms of a plurality of output signals output through the multipath channel with a preset standard waveform, and includes:
the signal processing unit FPGA is used for transmitting the output signals to a central processing unit CPU, and the central processing unit CPU is used for matching the waveforms of the output signals output by the multipath channel with preset standard waveforms;
the matching method comprises the following steps:
for each digital waveform W, it is represented by a vector X containing m elements:
X＝[x 1 x 2 x 3 ...... x m-1 x m ]formula 1
Wherein, the element x i The amplitude of a certain point of the waveform is obtained, and the time intervals between two adjacent elements are equal; carrying out normalization processing on the vector X, wherein the vector X can be used as a matching template signal;
normalizing the input waveform Y:
during the matching process of the waveforms, the distance D between the input waveform vector Y and the vector X is defined:
D＝||X-Y|| 2
＝Σ(x i -p i ) (i =1,2 \8230m) formula 3
Respectively inputting comb wave signals with different frequency multiplication numbers, and determining the waveform corresponding to the minimum distance as a normal comb wave signal;
and the judging unit is used for judging the data acquisition accuracy of the optical fiber current transformer according to the difference analysis result and the matching result.
6. The system of claim 5, the first data analysis unit for performing a difference analysis on a plurality of output signals output through the multipath channel, comprising:
and transmitting the output signals to a Central Processing Unit (CPU) by using a signal processing unit (FPGA), and performing difference value analysis on the output signals output by the multi-channel by using the CPU.
7. The system of claim 5, wherein the acquired signal is a comb having characteristic parameters.
8. The system according to claim 5, further comprising an output unit for outputting the difference analysis result and the matching result in a transmission frame format FT 3.
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| CN112904070B (en) * | 2019-11-19 | 2023-12-29 | 许继集团有限公司 | All-fiber current transformer, detection module thereof and optical path state diagnosis method |
| 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 |
| 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 |
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