Ultrahigh frequency sensor maximum response attenuation verification method considering environmental influence

Abstract

The invention provides a verification method for calculating the maximum response attenuation of a GIS ultrahigh frequency sensor. The verification method comprises the steps that a standard sensor is used for injecting a discharge signal to a sensor adjacent to a to-be-tested sensor; calculating the maximum response attenuation of the sensor at the temperature according to the local actual temperature; 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, and when the signal attenuation amplitude is higher than the maximum response attenuation, determining that the sensor to be tested has a performance fault and needing to be verified. 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 maximum response attenuation verification method for 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 the sensor layout in GIS based on the original characteristic parameters. Therefore, there is no unified calibration method in China. For straight-tube 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 temperature changes, the temperature of each point of the cable does not change to the same extent. Therefore, the material expansion and contraction degree of each point is different. This leads to an increase in the imbalance of the characteristic impedance of the cable, a decrease in the absolute value of the return loss, and a decrease in the sensitivity of the sensor. Therefore, it is necessary to correct the original formula to consider the effect of temperature on the sensitivity of the sensor.

[0003] The 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 using only one standard sensor and the sensor to be tested and injecting a partial discharge signal only once, thereby reducing the calibration equipment and the calibration process, while taking into account the influence of temperature 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 maximum response attenuation calibration method of a UHF sensor taking environmental influence into account, 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 temperature 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] 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.

[0012] 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

[0013] The present invention is further described below in conjunction with a specific implementation process. It should be emphasized that the specific implementation case described herein is only used to explain the present invention patent, and is not used to limit the scope of the present invention patent concept and its claims.

[0014] Embodiment 1

[0015] 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:

[0016] Step S1: Calculate the maximum response attenuation L of the sensor at the temperature according to the actual temperature on the day of verification.

[0017] Specifically, this step includes the following process:

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

[0019] β=|TT N |*K

[0020] E i =E i25。c *β

[0021] Where β is the temperature coefficient, T is the actual temperature measured on site, and T N is the standard room temperature, K is the simulation correction coefficient, and Ei25℃ is the sensor sensitivity at the standard room temperature of 25 degrees Celsius.

[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 response attenuation of the sensor at the current field temperature.

[0024] L = 20lg (E * E i25。c *β / 775)-AD-2

[0025] Wherein, E is the electric field strength measured by the minimum partial discharge signal at the sensor to be tested, which is the electric field strength generated at the sensor by the minimum partial discharge, A is the cable attenuation, D is the sensitivity of the monitoring system, and 2 is the system margin.

[0026] 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.

[0027] Specifically, this step includes the following process:

[0028] 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.

[0029] 2. Inject an equivalent 5pc partial discharge signal through a standard sensor.

[0030] Step S3: receiving the UHF signal sent back by the sensor to be tested.

[0031] Step S4: Acquire and process the partial discharge signal data received by the sensor to be tested.

[0032] Specifically, this step includes the following process:

[0033] 1. Read the received data sent back by the sensor to be tested through the detection system and calculate its signal attenuation.

[0034] 2. Compare the maximum response attenuation of the sensor at the field temperature 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.

Claims

1. A method for verifying the maximum response of a GIS ultra-high frequency sensor, characterized in that: The steps include: S1: Calculate the maximum response attenuation L of the sensor at this temperature based on the actual local temperature T (Fahrenheit); S2: Use a standard sensor to inject a discharge signal at the sensor adjacent to the sensor to be tested, and its amplitude is the minimum partial discharge; S3: using the sensor to be tested to receive the partial discharge signal; S4: Obtain the partial discharge signal data received by the sensor to be tested. If the signal attenuation is higher than the maximum response 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 response attenuation of the GIS UHF sensor according to claim 1, characterized in that: In step S1, the maximum attenuation response of the UHF sensor is calculated as follows: L=20lg(E*E i25。c *β / 775)-AD-2 (1) The electric field strength measured by the minimum partial discharge signal at the sensor to be tested is taken as the electric field strength E generated by the minimum partial discharge at the sensor; (2) The actual ambient temperature at this time is taken as the actual average temperature T of the sensor; (3) The relationship between sensor sensitivity and temperature is as follows: AND i =And i25。c *β E i25℃ is the sensor sensitivity at standard room temperature of 25 degrees Celsius, and the temperature coefficient β is the coefficient obtained by simulation, 0<β≤1.

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 maximum corresponding attenuation of the sensor at the temperature.

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