Transformer insulation aging monitoring method

Abstract

The invention relates to the technical field of aging monitoring, in particular to a transformer insulation aging monitoring method. The method comprises the following steps: acquiring monitoring items of each transformer insulation aging product, and calculating the optimization degree of the transformer insulation aging product; in combination with historical aging monitoring data, transformer insulation aging products associated with each other are screened, and combined aging product monitoring items are established. According to the invention, the optimization degree of the aging product is calculated through the monitoring item of each transformer insulation aging product, the acquisition syn-position of the aging product is planned by using the optimization degree, and the aging product is displayed and marked in cooperation with the established combined aging product monitoring item, so that ordered combined monitoring is realized; in the specific monitoring process, collection syn-position of various appearing aging products is planned according to the product sampling time, syn-position monitoring work of different processes of monitoring work is achieved, it is guaranteed that monitoring is carried out in order, the prediction accuracy can be improved, meanwhile, range aging product monitoring can be avoided, and the monitoring efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aging monitoring, in particular, to a transformer insulation aging monitoring method. BACKGROUND

[0002] The transformer is a key equipment in the power system, and its insulation system will be aged due to thermal, electrical, mechanical and chemical stresses in long-term operation, resulting in a decline in insulation performance and even causing a fault. Monitoring the insulation aging state is crucial for preventing equipment failure, prolonging the life of the transformer and ensuring the safety of the power grid.

[0003] The basic principle of insulation aging monitoring is based on the influence of the aging process on the physical and chemical properties of the material. Aging will cause changes in the molecular structure of the insulation oil and paper (such as cellulose degradation), which is manifested as abnormalities in electrical parameters (such as dielectric constant, resistance) or chemical indicators (such as gas generation). The main aging manifestations include changes in dissolved gas (hydrogen, methane, etc.) content, water content, acid value (total acid) and low molecular organic acid content, etc. The aging state of the transformer insulation can be predicted by monitoring the content of these aging products.

[0004] However, in the actual monitoring process, due to the differences in the monitoring methods of different aging products, the difficulty is different. If only the content of a single aging product is monitored for aging prediction, the prediction accuracy is low. Although the prediction accuracy can be improved by combining multiple aging products, the disordered combination method not only increases the collection difficulty, but also does not significantly improve the prediction accuracy.

[0005] In order to solve the above problems, there is an urgent need for a transformer insulation aging monitoring method with ordered combination of aging products. SUMMARY

[0006] The purpose of the present application is to provide a transformer insulation aging monitoring method to solve the problems raised in the background.

[0007] To achieve the above purpose, a transformer insulation aging monitoring method is provided, comprising the following steps: S1, collecting historical aging monitoring data, and establishing a transformer insulation aging product database; S2, obtaining monitoring items of each transformer insulation aging product , calculating the optimization degree of the transformer insulation aging product ; S3, combining the historical aging monitoring data, screening the transformer insulation aging products related to each other, and establishing a combined aging product monitoring item; S4, calculating the optimization degree of the transformer insulation aging product in the combined aging product monitoring item Ranking, making priority monitoring order, and marking the appearance of aging products; S5, collecting monitoring samples, extracting the appearance of aging products, and extracting the associated combination aging product monitoring items according to the appearance of aging products.

[0008] As a further improvement of the technical solution, the aging monitoring data in S1 includes aging products and chemical property changes.

[0009] As a further improvement of the technical solution, the monitoring items in S2 include product sampling time , detection consumption time , and detection success rate ; Among them, the detection success rate is the ratio of the number of samples successfully detected to the total number of samples; The product sampling time is the time consumed to separate the aging products from the sample; The detection consumption time is the time consumed to detect the content of aging products or the amount of chemical property changes.

[0010] As a further improvement of the technical solution, the optimization degree in S2 is calculated according to the following formula: ; Among them, is the adjustment coefficient of product sampling time , whose value range is , is the adjustment coefficient of detection consumption time , whose value range is , and .

[0011] As a further improvement of the technical solution, the combination aging product monitoring items in S3 include furfural and dissolved gas combination monitoring items, acid value and low molecular organic acid combination monitoring items, water + furfural + sludge combination monitoring items, and dielectric loss + dissolved gas multi-component combination monitoring items.

[0012] As a further improvement of the technical solution, the monitoring method of the furfural and dissolved gas combination monitoring item includes the following steps: S3.1.1, collect the furfural content in the sample, and mark it as ; S3.1.2, collect the value of in the sample, and mark it as ; S3.1.3, establishing the aging rate equation: ; wherein is the aging index, is the paper polymerization degree attenuation coefficient, and , is the furfural content, is the thermal stress factor, and , is and content ratio.

[0013] As a further improvement of the technical solution, the monitoring method of the acid value and low molecular organic acid combination monitoring item adopts a double-index threshold for judgment: When the acid value is > 0.3 mgKOH / g and the acetic acid is > 35 ppm, it indicates that the entire transformer is in the accelerated aging stage; When the acid value is > 0.5 mgKOH / g and the formic acid is > 15 ppm, it indicates that the oil sludge in the transformer is at the critical point of generation.

[0014] As a further improvement of the technical solution, the moisture + furfural + oil sludge combination monitoring item adopts an oil sludge trend prediction model for monitoring: ; wherein is the risk index, is the water content in the sample, is the furfural content in the sample; When the risk index > 80, the entire transformer is at high oil sludge risk; When 80 ≥ the risk index > 50, the entire transformer is at medium oil sludge risk; When the risk index ≤ 50, it is at low oil sludge risk.

[0015] As a further improvement of the technical solution, the monitoring method of the dielectric loss + dissolved gas multi-component combination monitoring item includes the following steps: S3.2.1, monitoring the dielectric loss factor of the transformer in working state, wherein the dielectric loss factor is the ratio of active power loss P to reactive power Q, i.e. , wherein is the dielectric loss factor; S3.2.2, establishing the conventional range of dielectric loss factor; When the dielectric loss factor does not exceed the conventional range, the current transformer is in normal state; When the dielectric loss factor is out of the normal range, the current transformer is in an abnormal state, and the determination is made in combination with the dissolved gas multi-component value; When the value of the ratio of the first component to the second component is greater than 2, it indicates that the current transformer is abnormally discharged; When the value of the ratio of the first component to the second component is greater than 2, it indicates that the current transformer is abnormally discharged; When the value of the ratio of the first component to the second component is greater than 0.5, it indicates that the current transformer is overheated. When the value of the ratio of the first component to the second component is greater than 0.5, it indicates that the current transformer is overheated.

[0016] As a further improvement of the technical solution, the method of extracting the associated combined aging product monitoring item according to the apparent aging product in S5 includes the following steps: S5.1, product sampling time of apparent aging product As the extraction order, and the product sampling time is inversely proportional to the extraction order; S5.2, sequentially collect according to the order of apparent aging product, and set the monitoring threshold of each apparent aging product; When the content of the apparent aging product does not exceed the monitoring threshold, the content of the apparent aging product of the next order is monitored; When the content of the apparent aging product exceeds the monitoring threshold, the corresponding combined aging product monitoring item is started.

[0017] Compared with the prior art, the beneficial effects of the present application are: In the transformer insulation aging monitoring method, the optimization degree of the aging product is calculated through each transformer insulation aging product monitoring item, the collection order of the aging product is planned by using the optimization degree, and the apparent aging product is marked by cooperating with the established combined aging product monitoring item, the ordered combined monitoring is realized, in the specific monitoring process, the collection order of each apparent aging product is planned according to the product sampling time, the order monitoring work of different processes of the monitoring work is realized, the ordered monitoring is ensured, the prediction accuracy is improved, and the range aging product monitoring is avoided, and the monitoring efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the overall flow chart of the present application; DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0020] Please refer to Figure 1As shown, a transformer insulation aging monitoring method is provided, comprising the following steps: S1. Collect historical aging monitoring data and establish a transformer insulation aging product database; S2. Obtain monitoring items for insulation aging products of each transformer , calculate the optimization degree of transformer insulation aging products ; S3. Combine historical aging monitoring data to screen interrelated transformer insulation aging products and establish combined aging product monitoring items; S4. Optimization of transformer insulation aging products in the combined aging product monitoring items Sort by, establish priority monitoring sequences, and mark visible aging products; S5. Collect monitoring samples, extract visible aging products, and extract associated combined aging product monitoring items based on the visible aging products.

[0021] The specific contents are as follows: First, to ensure the monitoring scope, it is necessary to collect historical aging monitoring data in advance and establish a database of transformer insulation aging products. During the collection process, aging product samples are extracted and the corresponding aging monitoring data is obtained using different monitoring methods. The aging monitoring data includes aging products (such as low-molecular organic acids, furfural, and sludge, etc.) and changes in chemical properties (such as changes in acid value). These can serve as the basis for subsequent prediction of the degree of transformer insulation aging.

[0022] In the actual monitoring process, due to the different difficulty levels in obtaining different aging monitoring data, in order to facilitate subsequent optimization and sorting, it is necessary to obtain the monitoring items of each transformer insulation aging product. , monitoring items in this plan Including product sampling time , Detection time and the success rate of detection , of which the detection success rate It is the ratio of the number of samples successfully tested to the total number of samples taken; Product sampling time The time it takes to separate aging products from the sample. When chemical property changes are used as aging monitoring data, the corresponding product sampling time is 0, because no separation is required; Detection time To detect the time consumed for detecting the content of aging products or the amount of chemical property change, such as in the process of detecting the content of furfural in aging products, first, the sample needs to be ultrasonically extracted by methanol, after centrifugation, the supernatant is filtered by an organic filter membrane, and then injected into a C18 reversed-phase chromatographic column, the mobile phase is methanol-water, and finally, the content is quantified by using a UV detector at a wavelength of 275 nm; Complete monitoring project After the acquisition work is completed, the optimization degree of the transformer insulation aging product needs to be calculated , and the specific calculation method is as follows: ; Among them, is the sampling time of the product , the value range of the adjustment coefficient is , is the adjustment coefficient of the detection time consumed , the value range is , and It is worth noting that the adjustment coefficient here is related to the model of the transformer, and the output type and content of the aging product of different models of transformers are different, and the sampling difficulty of the corresponding aging product is different. When the sampling difficulty increases, the value of will increase, and the value of will decrease, that is, The value is proportional to the sampling difficulty.

[0023] Further, in order to ensure the accuracy of monitoring, different aging products need to be monitored and fed back, and combined prediction is needed, so in the aging monitoring process, historical aging monitoring data needs to be combined to screen mutually related transformer insulation aging products, and combined aging product monitoring items are established. The combined aging product monitoring items in the present scheme include furfural and dissolved gas combined monitoring item, acid value and low molecular organic acid combined monitoring item, water + furfural + sludge combined monitoring item, and dielectric loss + dissolved gas multi-component combined monitoring item; Among them, for the furfural and dissolved gas combined monitoring item, furfural as a solid insulation paper aging characteristic product, combined with gas decomposed by reaction insulation material, the aging rate equation can be established: ; Among them, is the aging index, is the paper polymerization degree attenuation coefficient, and , is the furfural content, is the thermal stress factor, and , For With content ratio; For the combination of acid value and low molecular organic acid monitoring items, the total acid value evaluates the overall oxidation degree, and the concentration of formic acid / acetic acid indicates the risk of metal component corrosion. The dual-index threshold is used for judgment: Acid value > 0.3 mgKOH / g and acetic acid > 35 ppm Accelerated aging stage; Acid value > 0.5 mgKOH / g and formic acid > 15 ppm Sludge generation critical point; For the combination of moisture + furfural + sludge monitoring items, when the moisture content > 40 ppm, it is positively correlated with the furfural generation rate, and the prediction model is combined with the sludge trend to predict: ; Wherein is the risk index, is the water content in the sample, is the furfural content in the sample; When the risk index > 80, the entire transformer is at high sludge risk; When 80 ≥ risk index > 50, the entire transformer is at medium sludge risk; When the risk index ≤ 50, it is at low sludge risk; For the combination of dielectric loss + dissolved gas multi-component monitoring items, first, the dielectric loss factor normal range needs to be established; When the dielectric loss factor does not exceed the normal range, the current transformer is in normal state; When the dielectric loss factor exceeds the normal range, the current transformer is in abnormal state, and the dissolved gas multi-component value is used for judgment. When > 2, it indicates that the current transformer is abnormally discharged, and when > 0.5, it indicates that the current transformer is overheated (caused by aging).

[0024] Further, the combination of aging product monitoring items is used for monitoring, which not only increases the monitoring accuracy, but also avoids disordered monitoring and improves the monitoring efficiency. However, since there are multiple aging products in the combination of aging product monitoring items, how to select the appropriate combination of aging product monitoring items according to the performance of the monitoring sample becomes the key to improving the monitoring efficiency. In order to solve the above problems, the optimization degree of the transformer insulation aging product in the combination of aging product monitoring items needs to be sorted, and the optimization degree Inversely proportional to the monitoring order, that is, the degree of optimization The higher the corresponding ranking, the later the optimization degree. The lower the corresponding rank, the higher the priority. By combining the optimization degree of each aging product or chemical property change in the aging product monitoring item Sort by order and optimize The lowest aging product or chemical property change is marked as the visible aging product. After completing the collection of monitoring samples, the visible aging product is extracted. Since there are multiple visible aging products, it is determined by the number of combined aging product monitoring items. During the extraction process, the sampling time of the visible aging product is As the basis for extraction sequence, when multiple aging products appear at the same time, the product sampling time The smaller it is, the higher the ranking of the corresponding aging product is; During specific collection, the samples are collected sequentially according to the order of the manifested aging products, and a monitoring threshold is established for each manifested aging product. The monitoring threshold is determined based on the ratio of the manifested aging product to the total amount of samples actually collected. When the content of the manifested aging product exceeds the monitoring threshold, the corresponding combined aging product monitoring item is activated, that is, the remaining aging products or chemical property changes in the current combined aging product monitoring item are collected in sequence according to the order.

[0025] The present invention calculates the optimization degree of aging products through the monitoring items of various transformer insulation aging products, plans the collection sequence of aging products using the optimization degree, and uses the established combined aging product monitoring items to mark the visible aging products, thereby realizing orderly combined monitoring. In the specific monitoring process, the collection sequence of each visible aging product is planned according to the product sampling time, realizing the sequential monitoring of different monitoring processes, ensuring the orderly progress of monitoring, and improving the prediction accuracy while avoiding the scope of aging product monitoring and improving the monitoring efficiency.

[0026] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for monitoring transformer insulation aging, characterized in that: The steps include: S1. Collect historical aging monitoring data and establish a transformer insulation aging product database; S2. Obtain monitoring items for insulation aging products of each transformer , calculate the optimization degree of transformer insulation aging products ; S3. Combine historical aging monitoring data to screen interrelated transformer insulation aging products and establish combined aging product monitoring items; S4. Optimization of transformer insulation aging products in the combined aging product monitoring items Sort by, establish priority monitoring sequences, and mark visible aging products; S5. Collect monitoring samples, extract visible aging products, and extract associated combined aging product monitoring items based on the visible aging products.

2. The transformer insulation aging monitoring method according to claim 1, characterized in that: The aging monitoring data in S1 includes aging products and changes in chemical properties.

3. The transformer insulation aging monitoring method according to claim 1, characterized in that: The monitoring items in S2 Including product sampling time , Detection time and the detection success rate ; Among them, the detection success rate It is the ratio of the number of samples successfully tested to the total number of samples taken; Product sampling time The time taken to separate the aging products from the sample; Detection time The time consumed to detect the content of aging products or changes in chemical properties.

4. The transformer insulation aging monitoring method according to claim 3, characterized in that: The degree of optimization in S2 The calculation formula is as follows: ； in, Product sampling time The adjustment coefficient is in the range of , Time spent on detection The adjustment coefficient is in the range of ,and .

5. The transformer insulation aging monitoring method according to claim 1, characterized in that: The combined aging product monitoring items in S3 include furfural and Dissolved gas combined monitoring items, acid value and low molecular organic acid combined monitoring items, moisture + furfural + sludge combined monitoring items, and dielectric loss + dissolved gas multi-component combined monitoring items.

6. The transformer insulation aging monitoring method according to claim 5, characterized in that: The furfural and The monitoring method for the dissolved gas combination monitoring item includes the following steps: S3.1.

1. Collect the furfural content in the sample and mark it as ; S3.1.

2. Collect samples The value of ; S3.1.

3. Establish the aging rate equation: ； in is the aging index, is the paper polymerization attenuation coefficient, and , is the furfural content, is the thermal stress factor, and , for and Content ratio.

7. The transformer insulation aging monitoring method according to claim 5, characterized in that: The monitoring method for the combined monitoring item of acid value and low molecular weight organic acid adopts a dual-index threshold value for determination: When the acid value is greater than 0.3 mgKOH / g and the acetic acid is greater than 35 ppm, it indicates that the entire transformer is in the accelerated aging stage; When the acid value is greater than 0.5 mgKOH / g and the formic acid is greater than 15 ppm, it indicates that the sludge in the transformer is at the critical point of formation.

8. The transformer insulation aging monitoring method according to claim 5, characterized in that: The moisture + furfural + sludge combined monitoring item is monitored using the sludge trend prediction model: ； in is the risk index, is the water content in the sample, is the furfural content in the sample; When the risk index >80, the entire transformer is at high risk of oil sludge; When 80≥Risk Index When it is >50, the entire transformer is at medium oil sludge risk; When the risk index When ≤50, it is in low sludge risk.

9. The transformer insulation aging monitoring method according to claim 5, characterized in that: The monitoring method of the dielectric loss + dissolved gas multi-component combined monitoring item comprises the following steps: S3.2.

1. Monitor the dielectric loss factor of the transformer under working conditions, where the dielectric loss factor is the ratio of active power loss P to reactive power Q, that is, ,in is the dielectric loss factor; S3.2.

2. Establish a conventional range for dielectric loss factor; When the dielectric loss factor does not exceed the normal range, the current transformer is in normal condition; When the dielectric loss factor exceeds the normal range, the transformer is in an abnormal state and is judged in conjunction with the multi-component values ​​of dissolved gas; when When the value is greater than 2, it indicates abnormal discharge of the current transformer; when When the value is greater than 0.5, it indicates that the transformer is currently overheated.

10. The transformer insulation aging monitoring method according to claim 1, characterized in that: The method of extracting the associated combined aging product monitoring items according to the visible aging products in S5 comprises the following steps: S5.

1. Sampling time of products showing aging As the basis for extraction sequence, and product sampling time Inversely proportional to the extraction sequence; S5.

2. Collect data sequentially according to the order of the aging products that appear, and establish monitoring thresholds for each aging product that appears; When the content of the apparent aging product does not exceed the monitoring threshold, the next priority of the apparent aging product content monitoring is carried out; When the content of the apparent aging product exceeds the monitoring threshold, the corresponding combined aging product monitoring item is activated.

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