CN112964187A - Power transformer winding deformation detection device and method - Google Patents

Power transformer winding deformation detection device and method Download PDF

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Publication number
CN112964187A
CN112964187A CN202110169139.9A CN202110169139A CN112964187A CN 112964187 A CN112964187 A CN 112964187A CN 202110169139 A CN202110169139 A CN 202110169139A CN 112964187 A CN112964187 A CN 112964187A
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signal
optical fiber
transformer winding
frequency
deformation
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Inventor
孙路
曾四鸣
高树国
刘宏亮
赵军
邢超
孟令明
田源
李天然
陈二松
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Hebei Electric Power Co Ltd
State Grid Hebei Energy Technology Service Co Ltd
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Hebei Electric Power Co Ltd
State Grid Hebei Energy Technology Service Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00Measuring arrangements characterised by the use of optical techniques
    • G01B11/16Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge

Abstract

A power transformer winding deformation detection device and method, the device includes: the device comprises a pulse laser generating module, a measuring optical fiber, a photoelectric conversion module and an information processing module; the pulse laser generating module is used for generating a pulse laser signal with a set pulse width; the measuring optical fiber is attached to the lead of the transformer winding and keeps synchronous deformation with the lead, and a pulse laser signal enters the measuring optical fiber and returns a scattered light signal; the photoelectric conversion module is used for converting the return scattered light signals into intermediate frequency electric signals; and the information processing module is used for receiving the intermediate frequency electric signal, obtaining a Brillouin scattering spectrum, calculating corresponding optical fiber strain and judging the deformation degree of the transformer winding. Compared with the original winding capacitance method, the short-circuit impedance method and the pulse frequency response method, the method has the advantages of direct measurement of the deformation degree, high measurement precision and good effectiveness. The power failure test of the tested transformer is not needed, the detection work can be finished in a charged mode, and online real-time monitoring can be achieved.

Description

Power transformer winding deformation detection device and method
Technical Field
The invention belongs to the technical field of transformers, and particularly relates to a method and a device for detecting the deformation of a power transformer winding.
Background
With the continuous development of industry and economy, people have higher and higher requirements on electric power energy, and high-quality and reliable power supply forms the basis of normal operation of the modern society. The power transformer is used as a key device for power transmission and distribution in the power system and is responsible for the important task of system power transmission, especially, the large-scale high-voltage power transformer is located at the junction position of the system, and the operational reliability of the large-scale high-voltage power transformer directly influences the safety and stability of the power system.
At present, a winding electric capacity method, a short-circuit impedance method and a pulse frequency response method are mainly used for detecting the deformation of a transformer winding, but the methods all adopt an electric quantity detection mode, whether the winding is deformed or not and the deformation degree are deduced by detecting parameters such as the capacitance, the inductance and the impedance of the transformer winding, the detection precision is low, small deformation cannot be detected, and the misjudgment and the omission judgment risk are high.
Disclosure of Invention
In order to solve the defects in the prior art that the deformation of the power transformer winding cannot be accurately detected in real time, the invention aims to provide a method and a device for detecting the deformation of the power transformer winding.
The invention adopts the following technical scheme. The first aspect of the invention discloses a power transformer winding deformation detection device, which comprises: the device comprises a pulse laser generating module, a measuring optical fiber, a photoelectric conversion module and an information processing module; the pulse laser generating module is used for generating a pulse laser signal with a set pulse width; the measuring optical fiber is attached to the lead of the transformer winding and keeps synchronous deformation with the lead, and a pulse laser signal enters the measuring optical fiber and returns a scattered light signal; the photoelectric conversion module is used for converting the return scattered light signals into intermediate frequency electric signals; and the information processing module is used for receiving the intermediate frequency electric signal, obtaining a Brillouin scattering spectrum, calculating corresponding optical fiber strain and judging the deformation degree of the transformer winding.
Preferably, the pulsed laser generating module includes: a controllable laser source and a laser modulation unit; the controllable laser source is used for outputting a laser signal with a set frequency; the laser modulation unit is used for modulating the laser signal with the set frequency output by the controllable laser source and outputting the pulse laser signal with the set pulse width.
Preferably, the laser modulation unit comprises a light wave pulse modulator and an erbium-doped fiber amplifier; the light wave pulse modulator is used for converting continuous optical signals output by the controllable laser source into pulse signals, and the erbium-doped fiber amplifier is used for amplifying laser power.
Preferably, the measuring optical fiber is placed in the center of the wide surface of the wire wrapped with the insulating material, the measuring optical fiber and the wide surface of the wire are attached, and the insulating material used for wrapping and fixing is arranged outside the measuring optical fiber.
Preferably, the measuring optical fiber is a single-mode optical fiber, and the surface of the measuring optical fiber is wrapped by a polytetrafluoroethylene insulating sheath for optical fiber protection.
Preferably, the photoelectric conversion module includes: the microwave frequency mixing device comprises a photoelectric detector, a microwave frequency mixing unit and an analog-digital converter; the photoelectric detector is used for converting the return scattered light signals into corresponding frequency electric signals; the microwave frequency mixing unit is connected with the photoelectric detector and is used for mixing high-frequency signals generated by the photoelectric detector; the analog-to-digital converter is connected with the microwave frequency mixing unit and used for sampling the analog signal generated by the microwave frequency mixing unit and converting the analog signal into a digital signal.
Preferably, the microwave mixing unit comprises a preposed signal amplifier, a microwave oscillation source and a low-pass filter; the preposed signal amplifier is used for amplifying the power of the corresponding frequency electric signal generated by the photoelectric detector; the microwave oscillation source is used for outputting a sinusoidal signal with a set frequency, mixing the sinusoidal signal with a measurement signal in a mixer, and finally obtaining a processed signal through a low-pass filter.
Preferably, the outer end of the measuring optical fiber is linked with an optical fiber coupler, and the optical fiber coupler couples an input optical signal and an output optical signal of the measuring optical fiber to realize the combination/division of the optical signals.
A second aspect of the present invention provides a power transformer winding deformation detection method using the power transformer winding deformation detection apparatus, including the steps of:
step 1, modulating a laser signal with a set frequency into a pulse laser signal with a set pulse width, and injecting the pulse laser signal into a measuring optical fiber;
step 2, generating Brillouin scattering in the measuring optical fiber by the incident pulse laser signal, and returning a scattered light signal;
step 3, converting the return scattered light signals into intermediate-frequency electric signals, and taking the Brillouin scattering peak frequency with the maximum signal amplitude in the Brillouin scattering spectrum of the return scattered light signals as the initial Brillouin scattering peak frequency of the transformer winding;
step 4, when the deformation of the transformer winding is detected, repeating the steps 1 to 3 again to obtain the current Brillouin scattering peak frequency of the transformer winding, calculating the Brillouin scattering frequency shift Deltav according to the following formula,
Δv=vb-vb0
in the formula:
vbrepresenting the current brillouin scattering peak frequency of the transformer winding,
vb0representing the initial Brillouin scattering peak frequency of the transformer winding;
and step 5, calculating the corresponding optical fiber strain quantity delta epsilon according to the following formula by using the Brillouin scattering frequency shift delta v obtained in the step 4,
Figure BDA0002938379760000031
in the formula:
Cis a Brillouin frequency shift strain coefficient;
and 6, dividing a plurality of sections, wherein each section corresponds to different transformer winding deformation levels, and judging the deformation degree of the transformer winding according to the section to which the optical fiber strain delta epsilon obtained in the step 5 belongs.
Preferably, in step 3, the amplitude of the return signal at different frequencies can be obtained by periodically changing the operating frequency of the microwave oscillation source in the microwave frequency mixing unit and performing scanning detection on the return signal, and the corresponding frequency point of the return signal at the maximum amplitude is the brillouin scattering peak frequency vb
Preferably, step 4 further comprises: the position x on the measuring fiber where the deformation signal of the transformer winding returns is calculated as follows,
Figure BDA0002938379760000032
in the formula:
vopis the speed of light in the optical fiber,
Δ t represents the time difference between the initial signal and the return signal.
Preferably, in step 6, three intervals are divided, and if the delta epsilon [0 mu epsilon, 300 mu epsilon ], the three intervals are slightly deformed;
if delta epsilon (300 mu epsilon, 1000 mu epsilon) is a general deformation;
if Δ ε ∈ (1000 μ ε, + ∞ μ ε), it is a serious deformation.
Preferably, when the strain amount is detected, the measurement is repeated n times, n is more than or equal to 212The above steps are repeated. Or the pulse width l of the pulse laser signal is more than 30 ns. Or the microwave scanning frequency range is in the frequency range of 1MHz to 500Mhz, and the sweep frequency stepping length is in the frequency range of 1MHz to 10 MHz.
Compared with the prior art, the power transformer winding deformation detection device provided by the invention has the beneficial effects that the measurement optical fiber can be directly arranged on the surface of the transformer winding and synchronously moves along with the transformer winding, the winding deformation degree is directly measured by measuring the strain variation of the optical fiber, and compared with the original winding capacitance method, the short-circuit impedance method and the pulse frequency response method, the power transformer winding deformation detection device has the advantages of directly measuring the deformation degree, high measurement precision and good effectiveness.
The method for detecting the winding deformation of the power transformer does not need to perform a power failure test on the detected transformer, can complete detection work in a charged mode, and can realize online real-time monitoring of the winding deformation of the power transformer.
Drawings
FIG. 1 is a schematic view of a winding deformation detecting device of a power transformer according to the present invention;
FIG. 2 is a schematic view of the arrangement of the measuring fibers on the surface of the conducting wire according to the present invention;
FIG. 3 is a schematic diagram of a method for detecting deformation of a winding of a power transformer according to the present invention;
FIG. 4 is a schematic diagram of a medium-voltage-low-voltage burst short circuit test of the power transformer according to the present invention;
FIG. 5 shows the Brillouin scattering frequency shift result of the power transformer winding according to the present invention;
FIG. 6 shows the amount of strain in the windings of the power transformer according to the present invention.
1-a copper wire;
2-single mode fiber;
3-insulating paper;
4-testing the transformer;
5-a circuit breaker;
6-an isolating switch;
7-a reactor;
8-a current transformer;
9-a voltage transformer;
10-lightning arrester.
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present application is not limited thereby.
As shown in fig. 1, a first aspect of the present invention provides a power transformer winding deformation detection apparatus, including: the device comprises a pulse laser generation module, a measuring optical fiber, a photoelectric conversion module and an information processing module.
And the pulse laser generating module is used for generating a pulse laser signal with a set pulse width. It should be noted that any suitable pulsed laser signal generating device can be adopted by those skilled in the art as the pulsed laser generating module for generating the pulsed laser signal with the set pulse width. In a preferred but non-limiting embodiment, the pulsed laser generating module comprises: a controllable laser source and a laser modulation unit; the controllable laser source is used for outputting a laser signal with a set frequency; the laser modulation unit is used for modulating the laser signal with the set frequency output by the controllable laser source and outputting the pulse laser signal with the set pulse width.
As a further improvement of the present invention, the laser modulation unit comprises a light wave pulse modulator and an erbium-doped fiber amplifier; the light wave pulse modulator is used for converting continuous optical signals output by the controllable laser source into pulse signals, and the erbium-doped fiber amplifier is used for amplifying laser power.
The measuring optical fiber is attached to the transformer winding conductor and keeps synchronous deformation with the conductor, and the pulse laser signal enters the measuring optical fiber and returns a scattered light signal. It should be noted that, one skilled in the art can arbitrarily set the measuring fiber capable of maintaining synchronous deformation according to the structure of the transformer winding, and a preferred but non-limiting embodiment is that the measuring fiber is arranged on the surface of the transformer winding wire as shown in fig. 2. The measuring optical fiber is placed in the center of the wide surface of the electromagnetic wire wrapped with the insulating paper by using a little of white latex for a transformer, in order to better realize the detection of the deformation of the winding, the optical fiber and the wide surface of the copper conductor 1 are closely attached, and then the optical fiber and the winding are combined in a mode of obliquely wrapping and fixing by using the strip-shaped insulating paper 3, so that the optical fiber and the conductor are ensured to keep synchronous deformation.
The measuring optical fiber adopts a single mode optical fiber 2, and the surface of the measuring optical fiber is wrapped by a polytetrafluoroethylene material insulating sheath for optical fiber protection. It can be understood that, in order to avoid the failure of the detection system due to the breakage of the optical fiber in consideration of the sudden short circuit impact condition that may be encountered when the transformer is subjected to, a preferred but non-limiting embodiment is to arrange 3 measurement optical fibers synchronously, which are backup to each other, so as to improve the reliability of the system. The optical fiber is led out by adopting an optical fiber through device and a through flange plate which are arranged at the middle lower position on the side of the transformer oil tank shell, which is not the fan.
And the photoelectric conversion module is used for converting the return scattered light signals into intermediate frequency electric signals. It is noted that one skilled in the art can use any suitable photoelectric conversion module to convert the return scattered light signal into an intermediate frequency electrical signal. A preferred but non-limiting embodiment is that the photoelectric conversion module includes: the microwave frequency mixing device comprises a photoelectric detector, a microwave frequency mixing unit and an analog-digital converter; the photoelectric detector is used for converting the return scattered light signals into corresponding frequency electric signals; the microwave frequency mixing unit is connected with the photoelectric detector and is used for mixing high-frequency signals generated by the photoelectric detector; the analog-to-digital converter is connected with the microwave frequency mixing unit and used for sampling the analog signal generated by the microwave frequency mixing unit and converting the analog signal into a digital signal.
In a preferred but non-limiting embodiment, the signal sampling rate of the analog-to-digital converter is not lower than 500Mhz, and 4 channels of data are synchronously acquired.
The microwave frequency mixing unit comprises a preposed signal amplifier, a microwave oscillation source and a low-pass filter; the preposed signal amplifier is used for amplifying the power of the corresponding frequency electric signal generated by the photoelectric detector; the microwave oscillation source is used for outputting a sinusoidal signal with a set frequency, mixing the sinusoidal signal with a measurement signal in a mixer, and finally obtaining a processed signal through a low-pass filter. The upper cut-off frequency of the low-pass filter is 500 Mhz.
The outer end of the measuring optical fiber is connected with an optical fiber coupler, and the optical fiber coupler couples an input optical signal and an output optical signal of the measuring optical fiber to realize the combination/division of the optical signals.
And the information processing module is used for receiving the intermediate frequency electric signal, obtaining a Brillouin scattering spectrum, calculating corresponding optical fiber strain and judging the deformation degree of the transformer winding.
After the winding deformation detection device of the power transformer is installed, the transformer normally completes the production processes of body sleeving, iron inserting, furnace entering drying, final assembly and delivery test.
As shown in fig. 3, a second aspect of the present invention provides a power transformer winding deformation detection method using the power transformer winding deformation detection apparatus, including the steps of:
step 1, emitting frequency v by a controllable laser sourceoThe laser signal is modulated into a pulse laser signal with pulse width of l by the laser modulation module and is emitted into the measuring optical fiber. As a further improvement of the invention, in order to improve the measurement accuracy, the pulse width l of the pulse laser signal is required to be ensured to be more than 30 ns.
And 2, generating Brillouin scattering in the measuring optical fiber by the incident pulse laser signal and returning a scattered light signal.
And 3, converting the return signal into an intermediate frequency electric signal after photoelectric conversion, frequency mixing and analog-to-digital conversion. Searching for the Brillouin Scattering Spectrum g of the Return Signalb(v) The peak frequency of the Brillouin scattering with the maximum middle signal amplitude is used as the initial Brillouin scattering peak frequency v of the transformer windingb0. It can be understood that there is a direct correspondence between the brillouin scattering optical signal and the intermediate frequency electrical signal spectrum, and finding the maximum frequency of the amplitude of the electrical signal also results in the corresponding optical signal frequency of the reflected light.
Specifically, in the step 3,the amplitude of the return signal under different frequencies can be obtained by periodically changing the working frequency of a microwave oscillation source in the microwave frequency mixing unit and scanning and detecting the return signal, and the corresponding frequency point of the return signal when the amplitude is maximum is the Brillouin scattering peak frequency vb. As a further improvement of the invention, the microwave scanning frequency range is in the frequency range of 1MHz to 500Mhz, and the sweep frequency stepping length is in the frequency range of 1MHz to 10 MHz.
And (4) carrying out a sudden short circuit impact test on the tested transformer, artificially manufacturing the deformation conditions of the power transformer winding with different degrees, and continuing to carry out the transformer winding deformation detection step 4 after the short circuit test is finished.
Step 4, when the deformation of the transformer winding is detected, repeating the steps 1 to 3 again to obtain the current Brillouin scattering peak frequency of the transformer winding, calculating the Brillouin scattering frequency shift Deltav according to the following formula,
Δv=vb-vb0
in the formula:
vbrepresenting the current brillouin scattering peak frequency of the transformer winding,
vb0representing the initial Brillouin scattering peak frequency of the transformer winding;
as a further improvement of the present invention, step 4 further comprises: the fiber coupler combines an initial signal emitted by the pulse laser source and a return signal of the measuring fiber and inputs the combined signal into a subsequent processing module, and calculates the position x of the return position of the deformation signal of the transformer winding on the measuring fiber according to the time difference delta t between the initial signal and the return signal and the formula,
Figure BDA0002938379760000071
in the formula:
vopis the speed of light in the optical fiber, and is constant
Δ t represents the time difference between the initial signal and the return signal.
The method measures the initial strain quantity in the initial state of the transformer as a pairAnd (4) comparing and referring, measuring the strain amount after the suspected winding is deformed, and solving the change condition of the strain for comparison and judgment. As a further improvement of the invention, when the dependent variable is detected each time, including the initial and the subsequent, in order to improve the measurement precision, repeated measurement is carried out for multiple times to obtain an average value, the repeated measurement is represented by n, and n is generally 212The above steps are repeated.
And step 5, calculating the corresponding optical fiber strain quantity delta epsilon according to the following formula by using the Brillouin scattering frequency shift delta v obtained in the step 4,
Figure BDA0002938379760000072
in the formula:
Cis the brillouin frequency shift strain coefficient.
And 6, dividing a plurality of sections, wherein each section corresponds to different transformer winding deformation levels, and judging the deformation degree of the transformer winding according to the section to which the optical fiber strain delta epsilon obtained in the step 5 belongs.
As a further improvement of the present invention, in step 6, three intervals are divided, namely:
if delta epsilon belongs to [0 mu epsilon, 300 mu epsilon ], the deformation is slight;
if delta epsilon (300 mu epsilon, 1000 mu epsilon) is a general deformation;
if Δ ε ∈ (1000 μ ε, + ∞ μ ε), it is a serious deformation.
To further illustrate the improvements made and the benefits achieved by the present invention over the prior art, an example of an application of the present invention is described below.
The power transformer winding deformation detection device is arranged on a 110kV power transformer, and the transformer parameters are as follows:
table 1 application example transformer parameters
Figure BDA0002938379760000081
And carrying out a sudden short circuit impact test on the tested transformer, and artificially manufacturing the deformation conditions of the power transformer windings with different degrees. Taking a medium-voltage-low-voltage short circuit test as an example, a test voltage is applied between a phase terminal of a medium-voltage tested phase and the other two terminals connected together, a medium-voltage neutral point is grounded, and a low-voltage short circuit is grounded; the high voltage is open circuit, and the high voltage neutral point is grounded. The test current is designed separately here because the safety current is different due to the different structure of the three-phase low-voltage winding. Fig. 4 is a schematic diagram of a medium-voltage-low-voltage burst short circuit test of a power transformer, which includes: the device comprises a test transformer 4, a circuit breaker 5, a disconnecting switch 6, a reactor 7, a current transformer 8, a voltage transformer 9 and a lightning arrester 10. The experimental brillouin frequency shift results for different positions of the power transformer winding are shown in fig. 5. The resulting short-circuit transformer winding strain profile is shown in fig. 6.
According to the judgment of the test result, when the delta epsilon exceeds 8000 mu epsilon at 153.5 meters of the power transformer winding, the severe deformation is judged, the general deformation and the severe deformation also exist at the other parts, and the severe deformation of the power transformer winding is comprehensively judged.
Through the above detailed explanation of the inventive concept of the present application, it is clear to those skilled in the art that, compared with the prior art, the winding deformation detection device for the power transformer provided by the present invention can directly arrange the measurement optical fiber on the surface of the winding of the transformer, move synchronously with the winding of the transformer, and directly measure the deformation degree of the winding by measuring the strain variation of the optical fiber. The method for detecting the winding deformation of the power transformer does not need to perform a power failure test on the detected transformer, can complete detection work in a charged mode, and can realize online real-time monitoring of the winding deformation of the power transformer.
The present applicant has described and illustrated embodiments of the present invention in detail with reference to the accompanying drawings, but it should be understood by those skilled in the art that the above embodiments are merely preferred embodiments of the present invention, and the detailed description is only for the purpose of helping the reader to better understand the spirit of the present invention, and not for limiting the scope of the present invention, and on the contrary, any improvement or modification made based on the spirit of the present invention should fall within the scope of the present invention.

Claims (13)

1. A power transformer winding deformation detection device comprising: the device comprises a pulse laser generating module, a measuring optical fiber, a photoelectric conversion module and an information processing module; it is characterized in that the preparation method is characterized in that,
the pulse laser generating module is used for generating a pulse laser signal with a set pulse width;
the measuring optical fiber is attached to the lead of the transformer winding and keeps synchronous deformation with the lead, and a pulse laser signal enters the measuring optical fiber and returns a scattered light signal;
the photoelectric conversion module is used for converting the return scattered light signals into intermediate frequency electric signals;
and the information processing module is used for receiving the intermediate frequency electric signal, obtaining a Brillouin scattering spectrum, calculating corresponding optical fiber strain and judging the deformation degree of the transformer winding.
2. A power transformer winding deformation sensing device according to claim 1, characterized by:
the pulse laser generation module includes: a controllable laser source and a laser modulation unit; the controllable laser source is used for outputting a laser signal with a set frequency; the laser modulation unit is used for modulating the laser signal with the set frequency output by the controllable laser source and outputting the pulse laser signal with the set pulse width.
3. A power transformer winding deformation sensing device according to claim 2, characterized in that:
the laser modulation unit comprises a light wave pulse modulator and an erbium-doped fiber amplifier; the light wave pulse modulator is used for converting continuous optical signals output by the controllable laser source into pulse signals, and the erbium-doped fiber amplifier is used for amplifying laser power.
4. A power transformer winding deformation sensing device according to claim 1, characterized by:
the measuring optical fiber is placed in the center of the wide surface of the conducting wire wrapped with the insulating material, the measuring optical fiber and the wide surface of the conducting wire are attached, and the insulating material used for wrapping and fixing is arranged outside the measuring optical fiber.
5. A power transformer winding deformation detection device according to claim 4, characterized in that:
the measuring optical fiber adopts a single mode optical fiber, and the surface of the measuring optical fiber is wrapped by a polytetrafluoroethylene material insulating sheath for optical fiber protection.
6. A power transformer winding deformation detection device according to any one of claims 1 to 5, characterized by:
the photoelectric conversion module includes: the microwave frequency mixing device comprises a photoelectric detector, a microwave frequency mixing unit and an analog-digital converter; the photoelectric detector is used for converting the return scattered light signals into corresponding frequency electric signals; the microwave frequency mixing unit is connected with the photoelectric detector and is used for mixing high-frequency signals generated by the photoelectric detector; the analog-to-digital converter is connected with the microwave frequency mixing unit and used for sampling the analog signal generated by the microwave frequency mixing unit and converting the analog signal into a digital signal.
7. A power transformer winding deformation detection device according to claim 6, characterized in that:
the microwave frequency mixing unit comprises a preposed signal amplifier, a microwave oscillation source and a low-pass filter; the preposed signal amplifier is used for amplifying the power of the corresponding frequency electric signal generated by the photoelectric detector; the microwave oscillation source is used for outputting a sinusoidal signal with a set frequency, mixing the sinusoidal signal with a measurement signal in a mixer, and finally obtaining a processed signal through a low-pass filter.
8. A power transformer winding deformation detection device according to any one of claims 1 to 5, characterized by:
the outer end of the measuring optical fiber is connected with an optical fiber coupler, and the optical fiber coupler couples an input optical signal and an output optical signal of the measuring optical fiber to realize the combination/division of the optical signals.
9. A power transformer winding deformation detection method using the power transformer winding deformation detection apparatus according to any one of claims 1 to 8, characterized by comprising the steps of:
step 1, modulating a laser signal with a set frequency into a pulse laser signal with a set pulse width, and injecting the pulse laser signal into a measuring optical fiber;
step 2, generating Brillouin scattering in the measuring optical fiber by the incident pulse laser signal, and returning a scattered light signal;
step 3, converting the return scattered light signals into intermediate-frequency electric signals, and taking the Brillouin scattering peak frequency with the maximum signal amplitude in the Brillouin scattering spectrum of the return scattered light signals as the initial Brillouin scattering peak frequency of the transformer winding;
step 4, when the deformation of the transformer winding is detected, repeating the steps 1 to 3 again to obtain the current Brillouin scattering peak frequency of the transformer winding, calculating the Brillouin scattering frequency shift Deltav according to the following formula,
Δv=vb-vb0
in the formula:
vbrepresenting the current brillouin scattering peak frequency of the transformer winding,
vb0representing the initial Brillouin scattering peak frequency of the transformer winding;
and step 5, calculating the corresponding optical fiber strain quantity delta epsilon according to the following formula by using the Brillouin scattering frequency shift delta v obtained in the step 4,
Figure FDA0002938379750000021
in the formula:
Cis a Brillouin frequency shift strain coefficient;
and 6, dividing a plurality of sections, wherein each section corresponds to different transformer winding deformation levels, and judging the deformation degree of the transformer winding according to the section to which the optical fiber strain delta epsilon obtained in the step 5 belongs.
10. A method for detecting deformation of a winding of a power transformer according to claim 9, characterized in that:
in step 3, the amplitude of the return signal under different frequencies can be obtained by periodically changing the working frequency of the microwave oscillation source in the microwave frequency mixing unit and scanning and detecting the return signal, and the corresponding frequency point of the return signal when the amplitude is maximum is the brillouin scattering peak frequency vb
11. A power transformer winding deformation detection method according to claim 9 or 10, characterized by:
the step 4 further comprises the following steps: the position x on the measuring fiber where the deformation signal of the transformer winding returns is calculated as follows,
Figure FDA0002938379750000031
in the formula:
vopis the speed of light in the optical fiber,
Δ t represents the time difference between the initial signal and the return signal.
12. A power transformer winding deformation detection method according to claim 9 or 10, characterized by:
in the step 6, three intervals are divided, and if delta epsilon belongs to [0 mu epsilon, 300 mu epsilon ], slight deformation is carried out;
if delta epsilon (300 mu epsilon, 1000 mu epsilon) is a general deformation;
if Δ ε ∈ (1000 μ ε, + ∞ μ ε), it is a serious deformation.
13. A power transformer winding deformation detection method according to any one of claims 9 to 12, characterized by:
when the dependent variable is detected, the measurement is repeated for n times, wherein n is more than or equal to 212The above steps are repeated. Or pulsesThe laser signal pulse width l is greater than 30 ns. Or the microwave scanning frequency range is in the frequency range of 1MHz to 500Mhz, and the sweep frequency stepping length is in the frequency range of 1MHz to 10 MHz.
CN202110169139.9A 2021-02-07 2021-02-07 Power transformer winding deformation detection device and method Pending CN112964187A (en)

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CN113983944A (en) * 2021-11-03 2022-01-28 国网辽宁省电力有限公司抚顺供电公司 Transformer winding deformation detection device

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