CN107247059B - Insulator fault detection device and method based on air thermal schlieren distribution - Google Patents
Insulator fault detection device and method based on air thermal schlieren distribution Download PDFInfo
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- CN107247059B CN107247059B CN201710430044.1A CN201710430044A CN107247059B CN 107247059 B CN107247059 B CN 107247059B CN 201710430044 A CN201710430044 A CN 201710430044A CN 107247059 B CN107247059 B CN 107247059B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1218—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing using optical methods; using charged particle, e.g. electron, beams or X-rays
Abstract
The invention discloses a fault detection device and method for a zero-value insulator based on air thermal schlieren distribution. The device comprises a light source module, a schlieren signal acquisition module consisting of a schlieren mirror, a second plane reflector, a knife edge device and a photosensitive plate, a data processing module and a computer. The method judges whether the insulator is normal or not by calculating whether the similarity comprehensive value of the collected curve of the normal operation of the insulator and the curve of the operation of the insulator to be detected is larger than a preset threshold value or not. The similarity comprehensive value considers the similarity and the distance between the curve of the normal work of the insulator and the curve of the work of the insulator to be detected. The method is visual and reliable, can save manpower and material resources, and has a great practical engineering application value.
Description
Technical Field
The invention relates to an insulator fault detection device and method, in particular to an insulator fault detection device and method based on air thermal schlieren distribution, and belongs to the technical field of power fault diagnosis.
Background
The insulator is a main insulating component in a power grid, particularly a transmission line, and is a key component for ensuring the electrical performance. At present, in overhead transmission lines and substations, the insulators used are mainly porcelain suspension insulators. The insulator in operation works in a complex environment with coexistence of strong electric field, mechanical stress, dirt, temperature and humidity for a long time, and the probability of failure is high. As the operating time increases, the insulation and mechanical properties of the insulator decrease, as a result of the electromechanical coupling, resulting in a zero or low value insulator, a phenomenon known as aging or degradation of the insulator.
The existence of the zero-value low-value insulator is equivalent to that partial insulation is short-circuited, so that the overall creepage distance of the insulator string is correspondingly reduced, and the flashover probability of the insulator string is greatly increased. Once flashover occurs, short-circuit current can pass through the interior of the insulator, thermal effect is generated, the steel cap of the insulator is often cracked and separated or steel feet are blown, serious accidents such as insulator string breakage, string falling, power line wire falling and the like occur, the local power grid is cracked, the whole power grid is broken and paralyzed, and the industrial and agricultural production and the stability of people life are seriously influenced. Meanwhile, the existence of a large number of low-value zero-value insulators increases the electric quantity loss, and a part of unknown electric quantity is lost.
The conventional zero-value low-value insulator detection means mainly comprise a voltage distribution method, an electric field measurement method, an ultrasonic method, an infrared thermal image temperature measurement method and an ultraviolet pulse method. The above methods all have their own advantages and disadvantages. The voltage distribution method has the advantages of intuitive operation and capability of accurately judging the performance change of the insulator, but has the disadvantages of large workload, poor safety, low efficiency and easy electromagnetic interference, and causes false detection and missed detection. The equipment used by the electric field measurement method is simple, the requirements on weather conditions such as temperature, humidity and wind speed are low, but the measurement and detection tasks at a plurality of positions are heavy. The ultrasonic method has the advantages of simple equipment, convenient operation and strong anti-interference capability, can accurately detect the zero-value insulator caused by cracking, is greatly influenced by environmental background noise, does not work on the low-value zero-value insulator which is cracked, and has certain limitation on ultrasonic waves. The infrared thermal imaging method is reliable and efficient, but the influence of the operating environment, meteorological conditions, detection time, distance and other factors of the insulator on the infrared thermal imaging method cannot be ignored, and early warning cannot be carried out. The ultraviolet imaging method has the advantages of good predictability, no weather limitation, high detection speed, long detection distance and simple operation, but only can observe stronger electricity-proof signals, is mainly suitable for observing partial discharge and is difficult to accurately detect zero-value insulators.
The heating condition of the zero-value low-value insulator is different from that of the normal insulator, and the phenomenon causes the difference between the surrounding density of the fault insulator and the normal condition. The schlieren technique can reflect the structure of the flow field by using the density gradient field of the flow field, the collimated parallel light beams of the light source are deflected when passing through the disturbed flow field area, a knife edge is arranged at the image plane of the light source, the image of the light source is cut by the knife edge in different degrees due to different density gradient changes of the disturbed flow field along the knife edge direction, so that light and shade changes are generated on the recording plane, and the brightness is increased or reduced in proportion to the density gradient changes of the disturbed flow field along the knife edge direction.
A simplified schematic diagram of part of the schlieren technique is shown in figure 1,s in the figure is a light source arranged on a schlieren mirror LS1Passes through the observation area of the test section at the focal point of (1), and is reflected by the schlieren lens LS2A knife edge K is placed on the focal plane. The knife edge can block half of the light source image, at the moment, in a disturbance area, a refractive index gradient exists in the direction vertical to the edge of the knife edge, the light beam is deflected, light rays without disturbance are represented in the graph, and broken lines represent light rays subjected to disturbance change. The light ray has an offset in the direction perpendicular to the edge of the blade
Displacement on knife edge plane
The displacement in the y direction causes a change in the light intensity at the corresponding location on the screen, with contrast C with respect to the background illumination:
when the schlieren system is adjusted, a is generally equal to h/2(h is the height of the light source), and 2a is the distance between the knife edge and the connecting line of the focal points of the two schlieren mirrors in the y-axis direction.
Disclosure of Invention
The invention aims to provide a fault detection method and a fault detection device of a zero-value insulator based on air thermal schlieren distribution.
In order to solve the technical problems, the invention adopts the technical scheme that:
the first technical scheme is as follows:
the utility model provides a fault detection device of zero value insulator based on air heat schlieren distributes which characterized in that: the schlieren sch; the center of a light-transmitting area of the light source module and the center of the insulator are on the same horizontal plane and directly irradiate the center of the schlieren; the center of the schlieren mirror and the center of the light-transmitting area are on the same horizontal plane and are vertically arranged with the parallel light emitted by the light source module; the second plane reflector horizontally projects the light rays reflected by the schlieren to the knife edge device, and the center of the knife edge device and the center of the second plane reflector are on the same horizontal plane;
parallel optical signals generated by the light source module penetrate through a disturbance area where the insulator is located and then are received by the schlieren signal acquisition module, the schlieren signal acquisition module converts the received optical signals into schlieren imaging electric signals and outputs the schlieren imaging electric signals to the data processing module, and the data processing module digitalizes, filters and adjusts the amplitude of the schlieren imaging electric signals and then transmits the schlieren imaging electric signals to the computer; the computer displays images and judges faults; the computer is provided with a detection module, the detection module fits the obtained digital signal into a tested smooth curved surface image, the tested smooth curved surface image and a normal smooth curved surface image when the insulator works normally are subjected to correlation processing, correlation coefficients are calculated, and whether zero-value insulators or low-value insulators exist is judged.
The light source module consists of a tungsten halogen lamp light source, a first plane reflector and a collimating mirror; the image of the tungsten halogen lamp light source in the first plane reflector is on the focal plane of the collimating mirror; the primary optical axes of the collimating mirror and the schlieren mirror are parallel to each other.
The photosensitive plate comprises a light detection circuit, a background plate and more than 1 photosensitive diode arranged on the background plate; the light detection circuit comprises a resistor RFResistance RLA photodiode connected between the forward input terminal and the reverse input terminal of the CMOS input amplifier, and a resistor RFA resistor R connected between the inverting input terminal and the output terminal of the CMOS input amplifierLIs connected between the output terminal of the CMOS input amplifier and the ground.
The second technical scheme is as follows:
the fault detection method of the fault detection device of the zero-value insulator based on the air thermal schlieren distribution comprises the following steps:
step 1: collecting a curve of normal work of the insulator: the curve of the insulator working normally is r1 ═ (x (t), y (t)), where x (t) is the change of the voltage on the photosensitive plate with time when the insulator is normal, and y (t) is the change of the voltage on the photosensitive plate with time; the slope is:
step 2: collecting a detection curve of the insulator to be detected during working: the detection curve is r2 ═ (p (t), q (t)), where p (t) is the change of the voltage of the x axis on the photosensitive plate with time during detection, and q (t) is the change of the voltage of the y axis on the photosensitive plate with time during detection; the slope is:
and step 3: and (3) similarity judgment: the method comprises the following specific steps:
step 3-1: calculating a correlation measure:
step 3-2: calculating the distance between the normal working curve and the detection curve of the insulator:
wherein | · | purple2Represents L2；
Step 3-3: judging whether the distance is smaller than a preset threshold epsilon, if so, turning to the step 3-4:
step 3-4: calculating a similarity comprehensive value:
step 3-5: and judging whether the comprehensive value is greater than a preset threshold value, if so, judging that the interior of the insulator has defects, and otherwise, judging that the insulator is normal.
The technical effect obtained by adopting the technical scheme is as follows:
1. the invention discloses a method for detecting zero-value low-value insulator defects by detecting air thermal schlieren distribution near an insulator. The method is visual and reliable, can save manpower and material resources, and has a great practical engineering application value.
2. The invention adopts the photosensitive plate to receive signals and directly converts light intensity signals into electric signals, thereby facilitating data processing, bringing convenience in actual operation and having lower manufacturing cost.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a schematic view of schlieren;
FIG. 2 is a schematic view of the structure of a photosensitive web in example 1;
FIG. 3 is a schematic circuit diagram of a light detecting circuit of the photosensitive web in embodiment 1;
FIG. 4 is a schematic structural view of embodiment 1.
Wherein: 1. a tungsten halogen lamp light source 2, a first plane reflector 3, a collimating mirror 4, a light-transmitting area 5 and a light source module; 6. insulator string 7, schlieren mirror 8, second plane mirror 9, knife edge device 10, photosensitive plate 11, schlieren signal acquisition module 12 and data processing module
Detailed Description
Example 1:
the utility model provides a fault detection device of zero value insulator based on air heat schlieren distributes which characterized in that: the schlieren sch; the center of a light-transmitting area of the light source module and the center of the insulator are on the same horizontal plane and directly irradiate the center of the schlieren; the center of the schlieren mirror and the center of the light-transmitting area are on the same horizontal plane and are vertically arranged with the parallel light emitted by the light source module; the second plane reflector horizontally projects the light rays reflected by the schlieren to the knife edge device, and the center of the knife edge device and the center of the second plane reflector are on the same horizontal plane;
parallel optical signals generated by the light source module penetrate through a disturbance area where the insulator is located and then are received by the schlieren signal acquisition module, the schlieren signal acquisition module converts the received optical signals into schlieren imaging electric signals and outputs the schlieren imaging electric signals to the data processing module, and the data processing module digitalizes, filters and adjusts the amplitude of the schlieren imaging electric signals and then transmits the schlieren imaging electric signals to the computer; the computer displays images and judges faults; and the computer is provided with a detection module, the detection module fits the obtained digital signal into a tested smooth curved surface image, the tested smooth curved surface image and the normal smooth curved surface image when the insulator normally works are subjected to correlation processing, correlation coefficients are calculated, and whether a fault insulator exists is judged.
The light source module consists of a tungsten halogen lamp light source, a first plane reflector and a collimating mirror; the image of the tungsten halogen lamp light source in the first plane reflector is on the focal plane of the collimating mirror; the primary optical axes of the collimating mirror and the schlieren mirror are parallel to each other.
The photosensitive plate comprises a light detection circuit, a background plate and more than 1 photosensitive diode arranged on the background plate; the light detection circuit comprises a resistor RFResistance RLA photodiode connected between the forward input terminal and the reverse input terminal of the CMOS input amplifier, and a resistor RFA resistor R connected between the inverting input terminal and the output terminal of the CMOS input amplifierLIs connected between the output terminal of the CMOS input amplifier and the ground.
Example 2:
the fault detection method of the fault detection device of the zero-value insulator based on the air thermal schlieren distribution comprises the following steps:
step 1: collecting a curve of normal work of the insulator: the curve of the insulator working normally is r1 ═ (x (t), y (t)), where x (t) is the change of the voltage on the photosensitive plate with time when the insulator is normal, and y (t) is the change of the voltage on the photosensitive plate with time; the slope is:
step 2: collecting a detection curve of the insulator to be detected during working: the detection curve is r2 ═ (p (t), q (t)), where p (t) is the change of the voltage of the x axis on the photosensitive plate with time during detection, and q (t) is the change of the voltage of the y axis on the photosensitive plate with time during detection; the slope is:
and step 3: and (3) similarity judgment: the method comprises the following specific steps:
step 3-1: calculating a correlation measure:
step 3-2: calculating the distance between the normal working curve and the detection curve of the insulator:
wherein | · | purple2Represents L2；
Step 3-3: judging whether the distance is smaller than a preset threshold epsilon, if so, turning to the step 3-4:
step 3-4: calculating a similarity comprehensive value:
step 3-5: and judging whether the comprehensive value is greater than a preset threshold value, if so, judging that the interior of the insulator has defects, and otherwise, judging that the insulator is normal.
Claims (4)
1. The utility model provides a fault detection device of zero value insulator based on air heat schlieren distributes which characterized in that: the schlieren sch; the center of a light-transmitting area of the light source module and the center of the insulator are on the same horizontal plane and directly irradiate the center of the schlieren; the center of the schlieren mirror and the center of the light-transmitting area are on the same horizontal plane and are vertically arranged with the parallel light emitted by the light source module; the second plane reflector horizontally projects the light rays reflected by the schlieren to the knife edge device, and the center of the knife edge device and the center of the second plane reflector are on the same horizontal plane;
parallel optical signals generated by the light source module penetrate through a disturbance area where the insulator is located and then are received by the schlieren signal acquisition module, the schlieren signal acquisition module converts the received optical signals into schlieren imaging electric signals and outputs the schlieren imaging electric signals to the data processing module, and the data processing module digitalizes, filters and adjusts the amplitude of the schlieren imaging electric signals and then transmits the schlieren imaging electric signals to the computer; the computer displays images and judges faults; the computer is provided with a detection module, the detection module fits the obtained digital signal into a tested smooth curved surface image, the tested smooth curved surface image and a normal smooth curved surface image when the insulator works normally are subjected to correlation processing, correlation coefficients are calculated, and whether zero-value insulators or low-value insulators exist is judged.
2. The fault detection device of zero-valued insulators based on air thermal schlieren distribution of claim 1, characterized in that: the light source module consists of a tungsten halogen lamp light source, a first plane reflector and a collimating mirror; the image of the tungsten halogen lamp light source in the first plane reflector is on the focal plane of the collimating mirror; the primary optical axes of the collimating mirror and the schlieren mirror are parallel to each other.
3. The fault detection device of zero-valued insulators based on air thermal schlieren distribution of claim 1, characterized in that: the photosensitive plate comprises a light detection circuit, a background plate and more than 1 photosensitive diode arranged on the background plate; the light detection circuit comprises a resistor RFResistance RLA photodiode connected between the forward input terminal and the reverse input terminal of the CMOS input amplifier, and a resistor RFA resistor connected between the inverting input terminal and the output terminal of the CMOS input amplifierRLIs connected between the output terminal of the CMOS input amplifier and the ground.
4. The fault detection method for the fault detection device of zero-valued insulators based on air thermal schlieren distribution as claimed in claim 1, comprising the steps of:
step 1: collecting a curve of normal work of the insulator: the normal working curve of the insulator is r1 ═ (x (t), y (t)), where x (t) is the change of the x-axis voltage on the photosensitive plate with time when the insulator is normal, y (t) is the change of the y-axis voltage on the photosensitive plate with time, and the slope is:
step 2: collecting a detection curve of the insulator to be detected during working: the detection curve is r2 ═ (p (t), q (t)), where p (t) is the change of the voltage of the x axis on the photosensitive plate with time during detection, and q (t) is the change of the voltage of the y axis on the photosensitive plate with time during detection; the slope is:
and step 3: and (3) similarity judgment: the method comprises the following specific steps:
step 3-1: calculating a correlation measure:
step 3-2: calculating the distance between the normal working curve and the detection curve of the insulator:
wherein | · | purple2Represents L2；
Step 3-3: judging whether the distance is smaller than a preset threshold epsilon, if so, turning to the step 3-4:
step 3-4: calculating a similarity comprehensive value:
step 3-5: and judging whether the comprehensive value is greater than a preset threshold value, if so, judging that the interior of the insulator has defects, and otherwise, judging that the insulator is normal.
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| CN111381134B (en) * | 2020-03-26 | 2021-07-16 | 国网湖北省电力有限公司电力科学研究院 | Infrared zero value diagnosis method and system for porcelain insulator string |
| CN111398339B (en) * | 2020-03-26 | 2022-08-30 | 国网浙江省电力有限公司电力科学研究院 | Method and system for analyzing and judging heating defects of composite insulator of on-site overhead line |
| CN113899657B (en) * | 2021-12-06 | 2022-02-18 | 中国空气动力研究与发展中心高速空气动力研究所 | Compressible Reynolds stress measurement method based on composite schlieren technology |
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