CN105259527B - A kind of test method that different ultraviolet imager testing results are calibrated - Google Patents

Abstract

The invention discloses a test method for calibrating the detection results of different ultraviolet imagers, which includes taking gain as a variable, using two ultraviolet imagers to test standard test objects under different gains, and obtaining two sets of test results; Compare the two sets of test results to determine the corresponding gains of the two UV imagers when they get equal or similar test results, that is, the equivalent gain; based on a set of test results of one of the UV imagers as the standard, the other will be used The result of a UV imager testing the actual test object at the second gain value is compared with the result of the UV imager testing the standard test object at the first gain value, wherein the first gain value is the same as the second gain value The gain value is the equivalent gain. After calibration by the test method of the present invention, the detection results of different ultraviolet imagers can be compared to accurately determine the discharge severity and insulation performance of the power insulation equipment.

Description

A test method for calibrating the detection results of different ultraviolet imagers

technical field

The invention relates to the technical field of ultraviolet detection of power equipment, in particular to a test method for calibrating the detection results of different ultraviolet imagers.

Background technique

Ultraviolet detection technology is a non-contact live detection technology gradually developed in recent years. It detects the severity of discharge and insulation performance by detecting the ultraviolet light of a specific band generated by the discharge of power insulation equipment. The UV discharge detection results mainly include the number of UV photons and the area of the UV spot. However, due to differences in different UV imagers, there may be a large gap between the number of UV photons and the area of the UV spot recorded at the same discharge point under the same gain setting. , which brings difficulties to the comparison of the detection results of different ultraviolet imagers, and also hinders the establishment of evaluation standards for the detection results of ultraviolet discharge. Most of the existing studies only give the research conclusions of a certain UV imager, ignoring the differences between different instruments, and the research conclusions cannot be directly used in the detection results of other UV imagers or the application results are inaccurate.

Contents of the invention

In order to solve the above technical problems, the present invention proposes a test method for calibrating the detection results of different ultraviolet imagers. After calibration by the test method of the present invention, the detection results of different ultraviolet imagers can be compared to accurately determine the power Discharge severity of insulating equipment and its insulating performance.

To achieve the above object, the present invention adopts the following technical solutions:

The invention discloses a test method for calibrating the detection results of different ultraviolet imagers, which comprises the following steps:

S1: taking gain as a variable and other parameters as quantitative, using the first ultraviolet imager to test the standard test object under different gains, and obtaining the first set of test results of the standard test object under different gains;

S2: Taking gain as a variable and other parameters as quantitative, using a second ultraviolet imager to test the standard test object under different gains, and obtain a second set of test results of the standard test object under different gains;

S3: Comparing the first set of test results with the second set of test results, and determining the corresponding gains of the first ultraviolet imager and the second ultraviolet imager when equal or similar test results are obtained , the corresponding gain is the equivalent gain of the first ultraviolet imager and the second ultraviolet imager, wherein similar test results mean that the value difference is less than or equal to 5%;

S4: Taking the first set of test results of the first ultraviolet imager as a standard, the test results of the actual test object using the second ultraviolet imager at the second gain value and the first ultraviolet imager The imager compares the test results of the standard test object under the first gain value, wherein the first gain value and the second gain value are the first UV imager and the second UV imaging The equivalent gain of the meter.

Preferably, both the first set of test results and the second set of test results are test results of the number of ultraviolet photons.

Preferably, both the first set of test results and the second set of test results are test results of ultraviolet spot area.

Preferably, the step of using the first ultraviolet imager or the second ultraviolet imager to test the standard test object specifically includes: selecting a rod electrode and a plate electrode as the test platform, and the tip of the rod electrode is at a distance of The plate electrode is 3-5 cm long, and the pressure is 10-15 kV, and the detection distance of the first ultraviolet imager or the second ultraviolet imager is 4-10 m.

Preferably, the step of using the first ultraviolet imager or the second ultraviolet imager to test the standard test object specifically includes: selecting insulator strings as the test platform, and hanging 10 to 15 pieces of insulator strings in each string The insulator is pressurized at 200-400kV, and the detection distance of the first ultraviolet imager or the second ultraviolet imager is 20-50m. Further, the insulator is a disk-shaped glass insulator.

Preferably, the first ultraviolet imager and the second ultraviolet imager are different instruments of the same model.

Preferably, the first ultraviolet imager or the second ultraviolet imager is used to test the standard test object at a gain of 40 to 180 with a step size of 10.

Compared with the prior art, the present invention has the beneficial effect that: through the test method of the present invention, the detection results of different ultraviolet imagers are calibrated, and the equivalent gains corresponding to different ultraviolet imagers are obtained, so that when testing through different ultraviolet imagers, it can By comparing their corresponding equivalent gains, the research conclusions of one UV imager can be applied to other UV imagers, so as to accurately determine the discharge severity and insulation performance of power insulation equipment.

Description of drawings

Fig. 1 is a flowchart of a test method for calibrating the detection results of different ultraviolet imagers according to an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and in combination with preferred embodiments.

Gain in the present invention refers to a parameter that the ultraviolet imager performs amplifying processing multiples to the received ultraviolet light signal, and the detection distance refers to the linear distance between the instrument lens of the ultraviolet imager and the discharge point; the detection result of the ultraviolet imager It mainly includes the number of ultraviolet photons and the area of the ultraviolet spot. The number of ultraviolet photons can be directly read from the screen of the ultraviolet imager. The area of the ultraviolet spot needs to be extracted from each frame of the discharge video by writing a program.

As shown in Figure 1, it is a flow chart of a test method for calibrating the detection results of different ultraviolet imagers according to an embodiment of the present invention, including the following steps:

S1: Taking gain as a variable and other parameters as quantitative, use the first ultraviolet imager to test the standard test object under different gains, and obtain the first set of test results of the standard test object under different gains;

S2: Taking gain as a variable and other parameters as quantitative, use the second ultraviolet imager to test the standard test object under different gains, and obtain the second set of test results of the standard test object under different gains;

S3: Comparing the first set of test results with the second set of test results, and determining the corresponding gains of the first ultraviolet imager and the second ultraviolet imager when equal or similar test results are obtained, the corresponding gains are the first The equivalent gain of the UV imager and the second UV imager, where the similar test results mean that the value difference is less than or equal to 5%;

S4: Taking the first set of test results of the first UV imager as the standard, the results of the actual test object tested by the second UV imager at the second gain value are compared with the results of the first UV imager at the first gain value The test results of the standard test object are compared, wherein the first gain value and the second gain value are equivalent gains of the first ultraviolet imager and the second ultraviolet imager.

Wherein, the first ultraviolet imager and the second ultraviolet imager are different instruments of the same model, and the above test results may be the test results of the number of ultraviolet photons or the area of ultraviolet spots. During the test, it should be noted that: (1) The discharge of electrical insulation equipment should be sufficiently obvious and severe: in order to reduce the test error, the number of ultraviolet photons and the area of ultraviolet spots generated by the discharge should be large enough, and the number of photons should reach at least 103 orders of magnitude. It is best to reach the order of magnitude of 104; the area of the ultraviolet light spot should be clearly identifiable to the naked eye, and it is best to reach the size of the insulator sheet in the picture, so as to ensure that the test device can generate an extremely uneven electric field, and the applied voltage is high enough to meet the requirements; (2 ) The discharge of power insulation equipment should be stable enough: in the test, the discharge intensity should be stable enough to keep the maximum fluctuation range of the number of ultraviolet photons and the area of ultraviolet spots within 10%. If the value is too large, it is impossible to distinguish whether the change of its value is due to fluctuation or other influencing factors. Enhancing the inhomogeneity of the electric field generated by the test device is conducive to improving the stability of the discharge; (3) The number of test results recorded by the instrument should be sufficient : Under each gain parameter, it is required to record more than 12 ultraviolet photon numbers and discharge videos longer than 10s in time, and take the average value as the photon value and spot area value under this parameter, which is also to reduce the discharge intensity fluctuation interference At the same time, it should be noted that the instrument is still in an unstable state during the first 1-2s of recording the discharge video and the number of ultraviolet photons, so the effective photon number and spot video should be counted from 2s later.

In some embodiments, the step of using the first ultraviolet imager or the second ultraviolet imager to test the standard test object specifically includes: selecting a rod electrode and a plate electrode as the test platform, and the tip of the rod electrode is 3~3~ from the plate electrode. 5cm, pressurized 10-15kV, the detection distance of the first ultraviolet imager or the second ultraviolet imager is 4-10m.

In another part of the embodiment, the step of using the first ultraviolet imager or the second ultraviolet imager to test the standard test object specifically includes: selecting insulator strings as the test platform, and hanging 10 to 15 pieces of insulators in each string of insulator strings, The pressure is 200-400kV, and the detection distance of the first ultraviolet imager or the second ultraviolet imager is 20-50m. Among them, the insulator can be a disc-shaped glass insulator.

In some embodiments, the first ultraviolet imager and the second ultraviolet imager are made in Israel, and the above test is performed on the standard test object with a gain of 10 as a step from 40 to 180.

The following combined examples illustrate the test methods for calibrating the detection results of different ultraviolet imagers.

Example 1 (calibration of the detection results of the number of ultraviolet photons of different ultraviolet imagers):

Both the first ultraviolet imager and the second ultraviolet imager use the DayCor SuperB model produced in Israel. The test platform is a rod electrode and a plate electrode. The tip of the rod electrode is a copper needle or iron needle with a diameter of 3mm. 5cm, pressurize 10~15kV (adjusted according to the actual situation), at this time, the tip of the rod electrode can produce a relatively stable and obvious discharge, the fluctuation range of the number of photons is within 10%, and the air gap will not be broken down at the same time.

Since it is a calibration test, it is recommended to conduct 4 groups to reduce accidental errors. Place the first UV imager and the second UV imager to be calibrated at the same position 4-10m away from the discharge point, adjust the direction of the instrument lens so that the discharge point is in the center of the screen, and adjust the UV photon counting frame to the maximum. In the first group of experiments, the gain was increased from 40 to 180 in steps of 10, and more than 12 UV photons were recorded at each gain value; in the second group of experiments, the gain was started from 180 in steps of 10 Reduce it to 40, and record more than 12 photons at each gain value; the third and fourth sets of experiments repeat the steps of the first two sets, and a total of 4 sets of test data are obtained.

Select the average of the last 8-10 photon numbers recorded at each gain as the UV photon value at that gain. Calculate the average value of the 4 sets of UV photon values obtained by the first UV imager and the second UV imager at each gain, as the final number of UV photons at this gain, and obtain all instruments in the range of 40 to 180 for each gain The number of photons at the value, compare the number of ultraviolet photons and the gain value of the first ultraviolet imager and the second ultraviolet imager, as shown in Table 1.

Table 1 The test results of the number of ultraviolet photons of the first ultraviolet imager and the second ultraviolet imager under different gain values

If the number of photons recorded by two instruments at a certain gain is equal or very close (the value difference is less than or equal to 5%), the two gain values are considered to be equivalent in recording the number of UV photons . As shown in Table 1, the gain values of 50, 60...180 of the first ultraviolet imager correspond to the gain values of 40, 50...170 of the second ultraviolet imager respectively, that is, the first ultraviolet imager is in The number of UV photons recorded at a gain of 50 was comparable to that of the second UV imager at a gain of 40. For example, if the detection result of the first ultraviolet imager is the national standard, it is stipulated that when the first ultraviolet imager detects that the number of photons exceeds 200 at a gain of 50, it is a serious discharge, and the second ultraviolet imager should detect it at a gain of 40 When the number of photons exceeds 200, it is a severe discharge, because the gain of the first UV imager is 50 and the gain of the second UV imager is 40. Only when the number of photons is detected is comparable, and the photons detected by the two are respectively under the corresponding equivalent gain. Numbers are equivalent and comparable.

In this example, a rod electrode and a plate electrode are used to form an extremely uneven electric field after pressurization, resulting in a stable and obvious discharge point. The UV imager to be calibrated is fixed at the same position, with the gain as a variable, and all instruments are used to record each The number of ultraviolet photons under the gain value can be used to obtain the change curve of the number of ultraviolet photons with the gain of each instrument, and compare the curves of different ultraviolet imagers to obtain the corresponding gain of different instruments when observing the number of ultraviolet photons of the same size, which is equal to After the equivalent gain is formed, the data of different ultraviolet imagers can be compared horizontally to eliminate the inaccuracy of the result judgment caused by the difference between different instruments, so as to more accurately judge the severity of the discharge of the power insulation equipment and its insulating properties.

Example 2 (calibration of the detection results of the ultraviolet spot area of different ultraviolet imagers):

Both the first ultraviolet imager and the second ultraviolet imager use the DayCor SuperB model produced in Israel. The test platform is a series of I-type insulators and LXP-120 small disc glass insulators. Each string hangs 10 to 15 pieces, and the pressure is about 300kV (Set between 200-400kV depending on the specific situation), so that the high-voltage end of the insulator string produces a violent and stable discharge point, and the fluctuation ratio of the spot area is within the range of 10%.

Since it is a calibration test, it is recommended to conduct 4 groups to reduce accidental errors. Fix the first ultraviolet imager and the second ultraviolet imager that need to be calibrated at the same position about 30m away from the insulator string, and adjust the direction of the instrument lens so that the discharge point is located in the center of the screen. In the first group of experiments, the gain increased from 40 to 180 in steps of 10, and the discharge video was recorded for more than 10s at each gain value; in the second group of experiments, the gain decreased from 180 in steps of 10 To 40, at each gain value, also record more than 10s of discharge video; the third and fourth groups of experiments repeat the steps of the first two groups, and a total of 4 groups of discharge videos are obtained.

Calculate the average value of the ultraviolet spot area of the last 200 frames of images (about 6s) in the discharge video recorded under each gain, and take it as the spot area value under the gain. Find the average value of the 4 ultraviolet spot area values obtained by the first ultraviolet imager and the second ultraviolet imager at each gain, as the final spot area under the gain, and obtain the first ultraviolet imager and the second ultraviolet imager The spot area at each gain value in the range of 40 to 180 is compared with the ultraviolet spot area and gain data of different instruments, as shown in Table 2.

Table 2 The test results of the ultraviolet spot area of the first ultraviolet imager and the second ultraviolet imager under different gain values

If the UV spot area recorded by the two instruments is equal or very close (the value difference is less than or equal to 5%) under a certain gain of each instrument, it is considered that the two gain values are equivalent in recording the UV spot area Only when the recorded UV spot area is comparable. As shown in Table 2, the gain values of the first ultraviolet imager are 60, 70...180 and the gain values of the second ultraviolet imager are 40, 50...160 respectively, that is, the first ultraviolet imaging The ultraviolet spot area recorded by the instrument when the gain value is 60 is comparable to that of the second ultraviolet imager b when the gain is 40. For example, if the detection result of the first ultraviolet imager is the national standard, it is stipulated that when the first ultraviolet imager detects that the spot area exceeds 2000 at a gain of 60, it is a serious discharge, and the second ultraviolet imager should detect it at a gain of 40 If the spot area exceeds 2000, it is a serious discharge, because the gain of the first UV imager is 60 and the gain of the second UV imager is 40. It is comparable when detecting the spot area, and the spots detected by the two are under the corresponding equivalent gain. The areas are equivalent and comparable.

In this example, the inhomogeneous electric field formed at the high-voltage end after the insulator string is pressurized is used to generate a stable and strong discharge point. The UV imager to be calibrated is placed at the same position, with the gain as the variable, and each instrument is used to record all The discharge video under the gain value, the area of the ultraviolet spot is extracted from the video, and the change curve of the spot area of each instrument with the gain is obtained. Compared with the curves of different ultraviolet imagers, it is obtained when different instruments observe the same size spot area. The gain value is the equivalent gain. After the equivalent gain is formed, the data of different ultraviolet imagers can be compared horizontally to eliminate the inaccuracy of the result judgment caused by the difference between different instruments, so as to judge more accurately Discharge severity and insulation performance of power insulation equipment.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art to which the present invention belongs, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and those with the same performance or use should be deemed to belong to the protection scope of the present invention.

Claims (5)

1. a kind of test method calibrated to different ultraviolet imager testing results, which is characterized in that include the following steps：

S1：Using gain as variable, other parameters are quantitative, using the first ultraviolet imager to standard testing object in different increasings It is tested under benefit, obtains first group test result of the standard testing object under different gains；

S2：Using gain as variable, other parameters are quantitative, using the second ultraviolet imager to the standard testing object in difference Gain under tested, obtain second group test result of the standard testing object under different gains；

S3：First group of test result is compared with second group of test result, determines first ultraviolet imagery Instrument corresponding gain when obtaining equal or similar test result with second ultraviolet imager, the corresponding gain It is the Equivalent Gain of first ultraviolet imager and second ultraviolet imager, to which different ultraviolet imagers are tested When can be compared by its corresponding Equivalent Gain, be less than or equal to wherein similar test result is exponential quantity difference 5%；

S4：Using first group of test result of first ultraviolet imager as standard, second ultraviolet imagery will be used The result that instrument tests actual test object under the second yield value is with first ultraviolet imager in the first gain The result tested for the standard testing object under value is compared, wherein first yield value increases with described second Beneficial value is the Equivalent Gain of first ultraviolet imager and second ultraviolet imager；

Wherein described first ultraviolet imager and the different instruments that second ultraviolet imager is same model, using described The step of one ultraviolet imager or second ultraviolet imager test the standard testing object specifically includes following Alternative one：

(a) select bar electrode and plate electrode for test platform, 3~5cm of plate electrode described in the distance between two tips of the bar electrode, pressurization The detecting distance of 10~15kV, first ultraviolet imager or second ultraviolet imager is 4~10m；

(b) it is test platform to select insulator chain, and the insulator chain of often going here and there hangs 10~15 insulators, pressurization 200~ The detecting distance of 400kV, first ultraviolet imager or second ultraviolet imager is 20~50m.

2. test method according to claim 1, which is characterized in that first group of test result and second group of survey Test result is the test result of ultraviolet light subnumber.

3. test method according to claim 1, which is characterized in that first group of test result and second group of survey Test result is the test result of ultraviolet hot spot area.

4. test method according to claim 1, which is characterized in that the insulator is dish-type glass insulator.

5. test method according to any one of claims 1 to 4, which is characterized in that use first ultraviolet imager Or second ultraviolet imager tests standard testing object in gain with 10 for step-length from 40 to 180.