An intelligent gas relay gas volume on-line monitoring method

Abstract

The application discloses an online gas volume monitoring method for an intelligent gas relay, the method detects the gas volume of the gas relay by using a capacitive liquid level sensor, a gas volume calculation model is established based on a dense point calibration method, a mapping relationship among the oil liquid level height of the gas relay, the capacitive measurement value and the gas volume is established, the model is further verified according to test data, and the gas volume is measured according to the capacitive measurement value after the verification is qualified. The application can realize real-time monitoring on the light gas volume state of the transformer, realizes accurate measurement on the irregular volume in the gas relay, can quickly analyze the gas gathered in the gas relay, and provides a basis for formulating a fault diagnosis strategy according to the comprehensive analysis on the health state of the transformer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power transformer state monitoring and fault diagnosis, in particular to an intelligent gas relay gas volume online monitoring method. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission or a recognition that the information forms part of the prior art already known to a person of ordinary skill in the art.

[0003] As the most important and expensive equipment in the power system, large oil-immersed power transformers account for a high proportion of power system accidents, which has a significant impact and harm on users and the power system.

[0004] At present, the gas protection still follows the traditional protection principle, and the related technology development is mainly concentrated in the structure optimization of the gas relay, such as the double-float ball type, float baffle type, open cup baffle type, etc. Relay mechanism, which partially solves the misoperation problem caused by mechanical disturbance such as oil pump start-stop and tank shaking by external force.

[0005] The traditional transformer non-electricity data acquisition method is to periodically read the meter and patrol on site. There are two main problems, first, the real-time data of the real volume of the gas relay is missing, which makes it difficult for us to accurately judge the transformer condition. The light gas volume, pressure, temperature and liquid level change of the transformer body exist the problem of not timely reaction. Due to the inability to grasp the real volume of the gas relay, it is difficult to identify false alarm conditions, which is not conducive to timely fault diagnosis. The second is the safety risk of equipment and personnel. For example, in a certain ultra-high voltage substation, when the light gas of the main transformer acts, the maintenance personnel check the gas relay and gas box of the main transformer on site according to the regulations, and carry out tests on the core and clamp grounding current of the main transformer body. During the process, the transformer explosion occurred, causing a serious accident. SUMMARY

[0006] In order to solve the above technical problems in the prior art, the present application provides an intelligent gas relay gas volume online monitoring method, which monitors the gas volume of the gas relay in real time through a capacitive liquid level sensor, timely reflects the gas accumulation in the gas relay, and identifies the light gas false alarm condition, thereby ensuring the safety of equipment and personnel.

[0007] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: an intelligent gas relay gas volume online monitoring method, comprising the following steps:

[0008] S01), select a capacitive liquid level sensor to detect the gas volume of the gas relay, and a bidirectional cross slot is provided between the upper and lower measuring holes of the capacitive liquid level sensor;

[0009] S02) Place the intelligent gas relay on the gas relay calibration test platform, set the light gas setting value to 200 mL, 250 mL, and 300 mL respectively, and test the correct rate of light gas protection action;

[0010] S03) Install and test the performance of RVV insulated multi-core wire, and detect the transmission accuracy of electrical signal after contact action.

[0011] S04) Install the capacitive liquid level sensor on the gas relay, start testing the performance of the capacitive liquid level sensor, and place the capacitive liquid level sensor in the transformer oil at liquid level heights of 50 mm, 70 mm, 90 mm, 110 mm and 130 mm for liquid level measurement, and analyze the measurement deviation;

[0012] S05) Install the capacitive liquid level sensor on the gas relay, start testing;

[0013] S06) Based on the dense point calibration method, a gas volume calculation model is established, a mapping relationship between the oil liquid level height of the gas relay, the capacitive measurement value and the gas volume is established, and the model is further verified according to the test data. After verification, the gas volume is measured according to the capacitive measurement value.

[0014] Further, the data acquisition process based on the dense point calibration method is as follows: first, assemble the gas protection unit and the volume measurement unit on the upper cover of the gas relay, then add 10 mL of transformer oil as a single addition amount to the inside of the gas relay; after the addition is completed, cover the upper cover of the gas relay, record the capacitive detection value of the corresponding capacitive liquid level sensor, remove the upper cover and measure the length of the part of the capacitive liquid level sensor that is not contaminated by the transformer oil with a vernier caliper, and then calculate the corresponding liquid level height; repeat the above steps until the inside of the gas relay is filled with oil. According to the capacitive value and gas volume value of this process, a capacitive value-gas volume calculation model is established, and the gas volume value is obtained by detecting the capacitive value of the capacitive sensor through the corresponding relationship in the model.

[0015] Further, the established gas volume calculation model is programmed to design a visual user interface to display light gas action information, and set communication, interface display and parameters in the menu bar; at the same time, it has data query function to query the gas volume at historical time of the gas relay.

[0016] Further, the visual user interface can display the values of up to three gas relays at the same time.

[0017] Further, a double-barrel capacitive liquid level sensor is used to detect the gas volume of the gas relay.

[0018] Furthermore, a power supply module provides DC power to the capacitive liquid level sensor, with a supply voltage of ±24V and a supply current of 0-20mA.

[0019] Furthermore, the capacitive liquid level sensor transmits data externally via an RS485 communication line.

[0020] The beneficial effects of this invention are as follows: This invention uses a capacitive liquid level sensor to detect the gas volume of a gas relay, enabling real-time monitoring of the light gas volume status of the transformer and rapid analysis of the gas accumulated inside the gas relay. This provides a basis for comprehensive analysis of the transformer's health status and the development of fault diagnosis strategies. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a gas relay gas monitoring and protection system;

[0022] Figure 2 This is a schematic diagram of a capacitive liquid level sensor;

[0023] Figure 3 This is a schematic diagram of a capacitive liquid level sensor installed on a gas relay.

[0024] Figure 4 This is a flowchart of the monitoring method described in the embodiment;

[0025] Figure 5 This is a schematic diagram illustrating the mapping relationship between capacitance value and gas volume value.

[0026] In the diagram: 1. Cable outlet, 2. Locking nut, 3. Sensor body, 4. Bidirectional cross slot, 5. Capacitive liquid level sensor, 6. Gas relay. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Example 1

[0031] This embodiment discloses a method for online monitoring of gas volume using an intelligent gas relay, such as... Figure 1 As shown, this method includes three aspects: 1. A gas protection unit, which uses a dual-float type actuating mechanism to alarm for excessive liquid level and achieve actuation protection; RVV insulated multi-core wire is used as the signal line to ensure the accuracy of electrical signal transmission. 2. A volume measurement unit, which uses a dual-cylinder capacitive sensor as the liquid level sensor to detect the gas volume of the gas relay; a shielded transmission line is used as the transmission line to ensure the reliability and accuracy of signal transmission; a gas volume calculation model based on dense point calibration is used to calculate the gas volume, and the data processing is implemented using a DSP data processor. 3. A data display unit, including local display and remote display. Local display uses an LCD screen, while remote display uses 3G transmission.

[0032] This embodiment uses a capacitive liquid level sensor to detect the gas volume of the gas relay, such as... Figure 2 As shown, the capacitive liquid level sensor includes a sensor body 3, a bidirectional cross slot 4 on the sensor body 3, a locking nut 2 for fixing the sensor, and a cable outlet 1 for power supply and signal transmission. The cable outlet 1 includes two power lines and two communication lines, wherein the capacitive liquid level sensor transmits data externally through the RS485 communication line, increasing the signal transmission distance.

[0033] like Figure 3 As shown, the capacitive liquid level sensor 5 is installed on the gas relay using a locking nut, and then the system begins operation.

[0034] like Figure 4 As shown, the online gas volume monitoring method for gas relays described in this embodiment includes the following steps:

[0035] S01) Select a capacitive liquid level sensor to detect the gas volume of the gas relay, and make a bidirectional cross groove between the upper and lower measuring holes of the capacitive liquid level sensor.

[0036] S02) Place the intelligent gas relay on the gas relay calibration test platform, set the light gas setting value to 200mL, 250mL and 300mL respectively, and test the accuracy of its light gas protection action.

[0037] S03) Install and test the performance of RVV insulated multi-core wires, and check the accuracy of electrical signal transmission after contact operation.

[0038] S04) Install the capacitive liquid level sensor on the gas relay and start testing the performance of the capacitive liquid level sensor. Place the capacitive liquid level sensor in transformer oil at liquid levels of 50mm, 70mm, 90mm, 110mm and 130mm respectively to measure the liquid level and analyze its measurement deviation.

[0039] S05) Install the capacitive liquid level sensor on the gas relay and begin testing;

[0040] S06) Based on the dense point calibration method, a gas volume calculation model was established, and the mapping relationship between the oil level of the gas relay, the capacitance measurement value and the gas volume was established. The model was further verified based on test data.

[0041] The mapping curve was statistically analyzed starting from an oil level of 50 mm, at which point the oil volume inside the gas relay was 586 mL. The data acquisition process based on the dense point calibration method is as follows: First, the gas protection unit and volume measurement unit were assembled onto the gas relay cover. Then, transformer oil was added to the gas relay in increments of 10 mL. After addition, the gas relay cover was closed, and the capacitance value of the corresponding capacitive level sensor was recorded. After removing the cover, the length of the uncontaminated portion of the capacitive level sensor was measured using calipers, and the corresponding liquid level height was calculated. This process was repeated until the gas relay was filled with oil. The relevant data are shown in Table 1. Based on the capacitance and gas volume values ​​during this process, a capacitance-gas volume calculation model was established as follows: Figure 5 As shown, the gas volume value is obtained by detecting the capacitance value of the capacitive sensor through the correspondence in the model.

[0042] Table 1. Liquid level height, capacitance measurements, and gas volume detection data.

[0043]

[0044] In this embodiment, five intermediate injection oil volumes were randomly selected to test the deviation of the calculation model. The test results are shown in Table 2.

[0045] Table 2 Intermediate data detection bias

[0046]

[0047] Conclusion: The gas volume calculation model established based on the dense point calibration method has a maximum deviation of 0.28%, which is less than 1%.

[0048] S07) The established gas volume calculation model will be programmed accordingly, and a visual user interface will be designed to display light gas action information. Up to three gas relay values ​​can be displayed simultaneously. Communication, interface display, and parameters can be set in the menu bar. At the same time, it has a data query function. After clicking the "Data Query" button, the gas volume of the gas relay at historical time can be queried.

[0049] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for online monitoring of gas volume of an intelligent gas relay, characterized in that: The method comprises the following steps: S01), selecting a capacitive liquid level sensor to detect the gas volume of the gas relay, and measuring the bidirectional cross slot between the upper and lower measuring holes of the capacitive liquid level sensor; S02), placing the intelligent gas relay on the gas relay calibration test platform, setting the light gas setting value to 200 mL, 250 mL, and 300 mL respectively, and testing the correct rate of light gas protection action; S03), installing and testing the performance of the RVV insulated multi-core wire, and detecting the transmission accuracy of the electric signal after the contact action; S04), installing the capacitive liquid level sensor on the gas relay, starting to test the performance of the capacitive liquid level sensor, and placing the capacitive liquid level sensor in transformer oil at liquid level heights of 50 mm, 70 mm, 90 mm, 110 mm, and 130 mm for liquid level height measurement, and analyzing the measurement deviation; S05), installing the capacitive liquid level sensor on the double-float ball gas relay, and starting the test; S06), establishing a gas volume calculation model based on the dense point calibration method, establishing the mapping relationship among the oil liquid level height of the gas relay, the capacitive measurement value, and the gas volume, further verifying the model according to the test data, and measuring the gas volume according to the capacitive measurement value after verification; The data acquisition process based on the dense point calibration method is as follows: first, assemble the gas protection unit and the volume measurement unit on the upper cover of the gas relay, then add transformer oil to the gas relay at a single addition amount of 10 mL of transformer oil; after the addition is completed, cover the upper cover of the gas relay, record the capacitive detection value of the corresponding capacitive liquid level sensor, remove the upper cover, and measure the length of the part of the capacitive liquid level sensor that is not contaminated by the transformer oil using a vernier caliper, and then calculate the corresponding liquid level height; repeat the above steps until the gas relay is filled with oil; according to the capacitive value and the gas volume value in this process, a capacitive value-gas volume calculation model is established, and the gas volume value is obtained by detecting the capacitive value of the capacitive sensor through the corresponding relationship in the model.

2. The method of claim 1, wherein the method comprises: The established gas volume calculation model is programmed to design a visual user interface, display light gas action information, and set communication, interface display, and parameters in the menu bar; at the same time, it has data query function to query the gas volume at historical time of the gas relay.

3. The method of claim 2, wherein the method further comprises: The visual user interface can display the values of three gas relays at the same time.

4. The method of claim 1, wherein the method comprises: A double-barrel capacitive liquid level sensor is used to detect the gas volume of the gas relay.

5. The method of claim 1, wherein the method comprises: The capacitive liquid level sensor is powered by a power module, with a supply voltage of ±24V and a supply current of 0-20mA.

6. The method of claim 1, wherein the method comprises: The capacitive liquid level sensor transmits data to the outside through the RS485 communication line.

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