Ultrahigh frequency sensor performance attenuation upper limit verification method considering environmental influence

Abstract

The invention provides an ultrahigh frequency sensor performance attenuation upper limit verification method considering environmental influence. The method comprises the following steps: injecting a discharge signal at a sensor adjacent to a sensor to be tested by using a standard sensor; calculating the performance attenuation upper limit of the sensor under the humidity according to the local actual relative humidity; receiving a partial discharge signal by using a to-be-tested sensor; and acquiring partial discharge signal data received by the sensor to be tested, determining that the sensor to be tested has a performance fault when the signal attenuation amplitude is higher than the performance attenuation upper limit, and needing to perform verification. The sensor verification method suitable for different on-site environments is considered, and the accuracy of sensor verification is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of partial discharge verification, and in particular to a method for verifying an upper limit of performance attenuation of a UHF sensor taking environmental influence into account. Background Art

[0002] For UHF sensors installed on GIS, their performance will be affected by the attenuation loss of UHF signal propagation and sensor distribution in GIS based on the original characteristic parameters. Therefore, there is no unified calibration method in China. For straight-cylinder GIS, because its structure is the simplest and most special, a method of comparing the actual attenuation loss of the UHF sensor to be tested with the maximum allowable attenuation loss can be used for calibration. However, when the humidity changes, the electromagnetic wave transmission loss increases with the increase of humidity, and at the same humidity, the higher the frequency of the electromagnetic wave, the greater the loss affected by humidity, resulting in a decrease in sensor sensitivity. Therefore, it is necessary to modify the original formula to consider the impact of humidity on sensor sensitivity.

[0003] This method can simplify the previous calibration method of comparing the signal attenuation between two standard sensors with the signal attenuation between one standard sensor into a simplified calibration method that uses only one standard sensor and the sensor to be tested and injects a partial discharge signal only once, thereby reducing the calibration equipment and the calibration process, while taking into account the influence of humidity on the sensitivity of the UHF sensor, further improving the calibration accuracy. Summary of the invention

[0004] The embodiment of the present invention provides a method for calibrating the upper limit of performance attenuation of a UHF sensor taking into account environmental influences, so as to solve the problem that the existing calibration method occupies a lot of equipment and has a complicated process.

[0005] In a first aspect, a method for calibrating a partial discharge sensor is provided, comprising:

[0006] Calculate and correct the maximum acceptable signal attenuation of the sensor according to the actual humidity on site;

[0007] Arranging the UHF sensor at the arrangement position of the outer wall of the GIS;

[0008] The sensor under test is controlled to receive the partial discharge signal injected by the standard sensor.

[0009] In a second aspect, a signal transmission system required for partial discharge ultra-high frequency verification is provided, including: a partial discharge signal injection line and a receiving signal feedback line.

[0010] In a third aspect, a computer-readable storage medium is provided, on which computer program instructions are stored; when the computer program instructions are executed by a processor, the calibration method of the ultra-high frequency partial discharge sensor as described in the embodiment of the first aspect is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0012] Figure 1 It is a schematic flow chart of a method for on-site calibration of a UHF sensor according to the first embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram of the on-site calibration method of the UHF sensor according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Embodiment 1

[0016] Embodiment 1 of the present invention discloses a calibration method for a UHF partial discharge sensor. The calibration method can be applied in actual field. The method of the embodiment of the present invention comprises the following steps:

[0017] Step S1: Calculate the upper limit L of the sensor's performance attenuation at the current humidity based on the actual humidity on the day of verification. Specifically, this step includes the following process:

[0018] 1. Place a humidity sensor on the outer wall of the GIS pipe to obtain the actual local humidity RH during calibration. Substitute it into the humidity coefficient calculation formula:

[0019] β=K·RH / RH N

[0020] S=S 30％ β

[0021] Where β is the humidity coefficient, K is the voltage level correction coefficient, 1 for 220kV, 2.2 for 500kV, S 30％ The sensor sensitivity at 30% relative humidity;

[0022] 2. Obtain the specific model of the sensor and its standard room temperature sensitivity, and calculate the detection sensitivity of the monitoring system through the equivalent height of the sensor and the length of the signal transmission line.

[0023] 3. Calculate the maximum allowable attenuation of the sensor under the current on-site humidity.

[0024] L1=(1+c)·20lg(E·S 30％ β / λ)

[0025] L2=(1+c)·20lg(E·S 30％ ·β / λ)+20β·lgF+20β·lgD

[0026] Wherein, L1 is a frequency-independent antenna such as a planar spiral antenna, L2 is a frequency-dependent antenna such as a microstrip antenna, F is the center operating frequency of the antenna, D is the distance between sensors, and E is the electric field strength measured at the sensor to be tested when an equivalent 5pc partial discharge signal is injected into the adjacent sensor. c is the cable loss of the calibration signal during transmission, usually taken as 0.05. λ is a constant, taken as 775.

[0027] Step S2: Use a standard sensor to inject a discharge signal at a sensor adjacent to the sensor to be tested, the amplitude of which is the minimum partial discharge.

[0028] Specifically, this step includes the following process:

[0029] 1. Install a standard sensor of the same model as the sensor to be tested at the position adjacent to the sensor to be tested.

[0030] 2. Inject an equivalent 5pc partial discharge signal through a standard sensor.

[0031] Step S3: receiving the UHF signal sent back by the sensor to be tested.

[0032] Step S4: Acquire and process the partial discharge signal data received by the sensor to be tested.

[0033] Specifically, this step includes the following process:

[0034] 1. Read the received data sent back by the sensor to be tested through the detection system and calculate its signal attenuation.

[0035] 2. Compare the upper limit of sensor performance attenuation under on-site humidity calculated in step S1 with the signal attenuation of the sensor to be tested obtained in step S4. If the signal attenuation is higher than the calculated value, the sensor is faulty and needs to be repaired.

[0036] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for checking the upper limit of UHF sensor performance attenuation taking into account environmental influences, characterized in that: The steps include: S1: Identify the antenna type in the sensor and calculate the maximum allowable attenuation L between sensors under the local actual humidity RH (relative humidity); S2: Use a standard sensor to inject a discharge signal at the sensor adjacent to the sensor to be tested, with an amplitude equivalent to 5pc partial discharge; S3: using the sensor to be tested to receive the partial discharge signal; S4: Obtaining partial discharge signal data received by the sensor to be tested. If the signal attenuation is higher than the maximum allowable attenuation, it can be determined that the sensor to be tested has a performance failure and needs to be verified.

2. The method for verifying the layout position of a GIS UHF sensor according to claim 1, characterized in that: In step S2, the method for verifying the placement of the UHF sensor is as follows: (1) Place the standard sensor adjacent to the sensor to be tested; (2) If it is not possible to place the sensor in position (1), place the standard sensor at an equal distance from the sensor to be tested and the adjacent sensor.

3. The method for calculating the maximum allowable attenuation of a GIS UHF sensor according to claim 1, characterized in that: In step S1, the maximum allowable attenuation of the UHF sensor is calculated as follows: L1=(1+c)·20lg(E·S 30％ ·β / λ) L2=(1+c)·20lg(E·S 30％ ·β / λ)+20β·lgF+20β·lgD (1) L1 is a frequency-independent antenna such as a planar spiral antenna, L2 is a frequency-dependent antenna such as a microstrip antenna, F is the center operating frequency of the antenna, D is the distance between sensors, and E is the electric field strength measured at the sensor to be tested when an equivalent 5pc partial discharge signal is injected into the adjacent sensor; (2) RH is the actual relative humidity measured on site, and RHN is the relative humidity of 30%; (3) The relationship between sensor sensitivity and humidity is as follows: β=K·RH / RH N S=S 30％ ·b Where β is the humidity coefficient, K is the voltage level correction coefficient, 1 for 220kV, 2.2 for 500kV, S 30％ The sensor sensitivity at 30% relative humidity; (4) c is the cable loss of the calibration signal during transmission, usually 0.05; λ is a constant, 775.

4. The method for processing GIS UHF sensor calibration data according to claim 1, characterized in that: In step S4, the processing method of the UHF sensor verification data is as follows: The average amplitude attenuation of the signal received by the sensor to be tested is calculated, and the obtained attenuation is compared with the calculated upper limit of the sensor performance attenuation under the humidity.

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