Method and system for evaluating anti-aging performance of a dry-type transformer casting insulation layer

Abstract

The present application relates to the technical field of transformer performance evaluation, and discloses a kind of evaluation method and system of dry-type transformer casting insulation layer anti-aging performance, its method by injecting multiple uniform increasing test currents to transformer casting winding, and carry out multiple aging cycle test, obtain the cycle number of transformer casting winding in multiple aging cycle test when local discharge signal highest amplitude appears, and the number of local discharge signal in each aging cycle test, and the highest amplitude of local discharge signal in each aging cycle test, and winding hot spot temperature in each aging cycle test, and operating environment temperature in each aging cycle test, calculate out anti-aging performance evaluation factor, compare anti-aging performance evaluation factor with preset factor threshold value, evaluate the anti-aging performance of transformer casting winding according to the comparison result, to improve the accuracy of dry-type transformer casting insulation layer anti-aging performance evaluation.

Description

Technical Field

[0001] This invention relates to the field of transformer performance evaluation technology, and in particular to a method and system for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer. Background Technology

[0002] Dry-type transformers are core equipment in power distribution networks. Due to their advantages such as fire and explosion protection, environmental friendliness, and lightweight design, they are used in large numbers in the power grid, and their reliable operation plays an extremely important role in the continuous and stable power supply of the grid. Dry-type transformer windings are usually cast with epoxy resin to seal the windings and strengthen insulation. However, depending on the application scenario, dry-type transformers often face harsh operating environments such as salt spray, condensation, and overload high temperatures. Under the influence of multiple factors, the epoxy resin-cast windings may become damp, leading to irreversible damage such as cracks and aging problems such as dielectric degradation, ultimately resulting in insulation failure and the end of the transformer's lifespan.

[0003] Statistics show that over 5,000 dry-type transformers are damaged by moisture each year. Furthermore, the insulation material of traditional epoxy resin cast transformers is difficult to recycle after they are scrapped. Researchers are actively developing new moisture-resistant and recyclable cast insulation materials for dry-type transformers. Currently, there is a lack of effective and accurate methods for evaluating the anti-aging performance of cast insulation layers in dry-type transformers; therefore, a method for evaluating the anti-aging performance of cast insulation layers in dry-type transformers is urgently needed. Summary of the Invention

[0004] This invention provides a method and system for evaluating the anti-aging performance of cast insulation layers in dry-type transformers, solving the technical problem of poor accuracy in evaluating the anti-aging performance of cast insulation layers in dry-type transformers.

[0005] In view of this, the first aspect of the present invention provides a method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer, characterized by comprising the following steps:

[0006] S1. By sequentially injecting multiple uniformly increasing test currents into the transformer casting winding, and performing multiple aging cycle tests on the transformer casting winding each time a test current is injected, the aging cycle tests include sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding.

[0007] S2. Obtain the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test.

[0008] S3. Based on the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer casting winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test, the aging factors corresponding to the multiple uniformly increasing test currents are calculated using the first preset formula.

[0009] S4. Calculate the anti-aging performance evaluation factor based on the aging factors corresponding to multiple uniformly increasing test currents using the second preset formula.

[0010] S5. Compare the anti-aging performance evaluation factor with the preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding based on the comparison result.

[0011] Preferably, the procedure before step S1 includes:

[0012] Step S0: Construct a test platform, which includes an environmental test chamber, wire inlet terminals, wire outlet terminals, a simulated power supply, and a terminal computer;

[0013] The environmental test chamber contains the transformer casting winding. Two environmental mist controllers are located at the top of the environmental test chamber, used to spray mist into the chamber. Four partial discharge ultrasonic monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to a terminal computer via a wire outlet terminal. These monitors are used to acquire partial discharge signals from the transformer casting winding. Four thermal imaging monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to the terminal computer via a wire outlet terminal. These monitors are used to acquire the temperature of the transformer casting winding and the interior of the environmental test chamber.

[0014] The simulated power supply is electrically connected to the transformer casting winding through the wire inlet terminal, and is used to inject test current into the transformer casting winding.

[0015] Preferably, step S1 specifically includes:

[0016] Three uniformly increasing test currents, denoted as I1, I2, and I3, are sequentially injected into the transformer's cast windings, where I1 = I... n I2 = 1.1I n I3 = 1.2I n I nThe rated current of the transformer cast winding is indicated. Each time a test current is injected, the transformer cast winding is subjected to 50 aging cycle tests. The aging cycle test includes sequentially spraying salt spray onto the transformer cast winding for 1 hour, spraying water spray for 2 hours, and stopping spraying for 3 hours.

[0017] Preferably, the first preset formula in step S3 is:

[0018]

[0019] In the formula, I represents the aging factor of the j-th injected test current. j This represents the j-th injected test current, where j = 1, 2, 3. This indicates the cycle number in which the highest amplitude of the partial discharge signal occurred out of 50 aging cycle tests. This indicates the highest amplitude of the partial discharge signal observed during 50 aging cycle tests. This indicates the number of partial discharge signals corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. This indicates the hot spot temperature of the transformer cast winding corresponding to the periodic test at which the partial discharge signal reaches its highest amplitude. The ambient temperature (T) corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. n This indicates the temperature rise limit of the thermal insulation class of the cast insulation material for the transformer cast windings. This indicates the highest amplitude of the partial discharge signal observed during the first aging cycle test. This indicates the number of times partial discharge signals appeared during the first aging cycle test. This indicates the hot spot temperature of the transformer casting winding during the first aging cycle test. This indicates the ambient temperature of the transformer casting winding during the first aging cycle test. This indicates the highest amplitude of the partial discharge signal observed during the 50th aging cycle test. This indicates the number of times partial discharge signals appeared during the 50th aging cycle test. This indicates the hot spot temperature of the transformer cast winding during the 50th aging cycle test. This indicates the ambient temperature of the transformer casting winding during the 50th aging cycle test. This represents the highest amplitude of the partial discharge signal observed during the i-th aging cycle test. This indicates the number of times a partial discharge signal appears during the i-th aging cycle test. This represents the hot spot temperature of the transformer casting winding during the i-th aging cycle test. This represents the ambient temperature of the transformer casting winding during the i-th aging cycle test.

[0020] Preferably, the second preset formula in step S4 is:

[0021]

[0022] In the formula, η est This represents the anti-aging performance evaluation factor.

[0023] Preferably, step S5 specifically includes:

[0024] Compare the anti-aging performance evaluation factor with 1. If 0 < η est If ≤1, it indicates that the anti-aging performance of the transformer cast winding insulation layer is good; if 1 < η est This indicates that the anti-aging performance of the transformer's cast winding insulation layer is poor.

[0025] Secondly, the present invention provides an evaluation system for the anti-aging performance of the cast insulation layer of a dry-type transformer, comprising:

[0026] The current injection module is used to inject multiple uniformly increasing test currents into the transformer casting winding in sequence. Each injection of test current performs multiple aging cycle tests on the transformer casting winding. The aging cycle tests include sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding.

[0027] The acquisition module is used to acquire the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test.

[0028] The first calculation module is used to calculate the aging factors corresponding to the injected multiple uniformly increasing test currents based on the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test, through a first preset formula.

[0029] The second calculation module is used to calculate the anti-aging performance evaluation factor according to the aging factors corresponding to multiple uniformly increasing test currents through a second preset formula.

[0030] The evaluation module is used to compare the anti-aging performance evaluation factor with a preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding based on the comparison result.

[0031] Preferably, the system further includes a construction module for constructing a test platform, the test platform including an environmental test chamber, wire inlet terminals, wire outlet terminals, a simulated power supply, and a terminal computer;

[0032] The environmental test chamber contains the transformer casting winding. Two environmental mist controllers are located at the top of the environmental test chamber, used to spray mist into the chamber. Four partial discharge ultrasonic monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to a terminal computer via a wire outlet terminal. These monitors are used to acquire partial discharge signals from the transformer casting winding. Four thermal imaging monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to the terminal computer via a wire outlet terminal. These monitors are used to acquire the temperature of the transformer casting winding and the interior of the environmental test chamber.

[0033] The simulated power supply is electrically connected to the transformer casting winding through the wire inlet terminal, and is used to inject test current into the transformer casting winding.

[0034] As can be seen from the above technical solutions, the present invention has the following advantages:

[0035] This invention considers the effects of factors such as salt spray, condensation, and overload high temperature on the cast insulation layer of dry-type transformers. It injects multiple uniformly increasing test currents into the cast windings of the transformer and conducts multiple aging cycle tests. The invention obtains the number of cycles in which the cast windings exhibit the highest amplitude of partial discharge signals during these aging cycle tests, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signals in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating ambient temperature in each aging cycle test. Based on this, an anti-aging performance evaluation factor is calculated. This factor is then compared with a preset factor threshold, and the anti-aging performance of the cast windings of the transformer is evaluated based on the comparison results, thereby improving the accuracy of the evaluation of the anti-aging performance of the cast insulation layer of dry-type transformers. Attached Figure Description

[0036] Figure 1 A flowchart illustrating a method for evaluating the anti-aging performance of cast insulation layers in dry-type transformers, provided as an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the testing platform provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of a system for evaluating the anti-aging performance of cast insulation layers in dry-type transformers, provided in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] For easier understanding, please refer to Figure 1 The present invention provides a method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer, comprising the following steps:

[0041] S1. By sequentially injecting multiple uniformly increasing test currents into the transformer casting winding, the transformer casting winding is subjected to multiple aging cycle tests each time a test current is injected. The aging cycle test includes sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding.

[0042] This requires simulating the actual operating environment of the transformer's cast windings. The amount of water vapor in the salt spray can be obtained based on the operating environment; the conductivity of the salt spray after condensation into liquid can be obtained based on the operating environment; the amount of water vapor in the water mist can be obtained based on the operating environment; and the conductivity of the water mist after condensation into liquid can be obtained based on the operating environment, thereby setting the operating environment.

[0043] The ambient water vapor content is determined by an external sensor, while the electrical conductivity is measured after the water vapor is condensed into a liquid state. Water vapor and its conductivity affect the insulation condition and temperature distribution of the transformer windings, thus influencing the aging of the insulation layer. These parameters are reflected in the aging test setup, which involves alternating spraying of salt spray and water mist. Determining the ambient water vapor content and conductivity is crucial to ensuring the aging test closely reflects actual operating conditions and yields more accurate results.

[0044] S2. Obtain the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test.

[0045] S3. Based on the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test, the aging factors corresponding to the injected uniformly increasing test currents are calculated using the first preset formula.

[0046] The first preset formula is:

[0047]

[0048] In the formula, I represents the aging factor of the j-th injected test current. j This represents the j-th injected test current, where j = 1, 2, 3. This indicates the cycle number in which the highest amplitude of the partial discharge signal occurred out of 50 aging cycle tests. This indicates the highest amplitude of the partial discharge signal observed during 50 aging cycle tests. This indicates the number of partial discharge signals corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. This indicates the hot spot temperature of the transformer cast winding corresponding to the periodic test at which the partial discharge signal reaches its highest amplitude. The ambient temperature (T) corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. n This indicates the temperature rise limit of the thermal insulation class of the cast insulation material for the transformer cast windings. This indicates the highest amplitude of the partial discharge signal observed during the first aging cycle test. This indicates the number of times partial discharge signals appeared during the first aging cycle test. This indicates the hot spot temperature of the transformer casting winding during the first aging cycle test. This indicates the ambient temperature of the transformer casting winding during the first aging cycle test. This indicates the highest amplitude of the partial discharge signal observed during the 50th aging cycle test. This indicates the number of times partial discharge signals appeared during the 50th aging cycle test. This indicates the hot spot temperature of the transformer cast winding during the 50th aging cycle test. This indicates the ambient temperature of the transformer casting winding during the 50th aging cycle test. This represents the highest amplitude of the partial discharge signal observed during the i-th aging cycle test. This indicates the number of times a partial discharge signal appears during the i-th aging cycle test. This represents the hot spot temperature of the transformer casting winding during the i-th aging cycle test. This represents the ambient temperature of the transformer casting winding during the i-th aging cycle test.

[0049] S4. Calculate the anti-aging performance evaluation factor based on the aging factors corresponding to multiple uniformly increasing test currents using the second preset formula.

[0050] The second preset formula is:

[0051]

[0052] In the formula, η est This represents the anti-aging performance evaluation factor.

[0053] S5. Compare the anti-aging performance evaluation factor with the preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding insulation layer based on the comparison results.

[0054] Among them, the anti-aging performance evaluation factor is compared with 1. If 0 < η est If ≤1, it indicates that the anti-aging performance of the transformer cast winding insulation layer is good; if 1 < η est This indicates that the anti-aging performance of the transformer's cast winding insulation layer is poor.

[0055] This embodiment provides a method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer. Considering the effects of salt spray, condensation, and overload high temperature on the cast insulation layer of the dry-type transformer, multiple uniformly increasing test currents are injected into the cast winding of the transformer, and multiple aging cycle tests are conducted. The method obtains the number of cycles in which the cast winding exhibits the highest amplitude of partial discharge signals during multiple aging cycle tests, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signals in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating ambient temperature in each aging cycle test. An anti-aging performance evaluation factor is calculated, and this factor is compared with a preset factor threshold. The anti-aging performance of the cast winding is evaluated based on the comparison results, thereby improving the accuracy of the evaluation of the anti-aging performance of the cast insulation layer of the dry-type transformer.

[0056] In one specific embodiment, the steps preceding step S1 include:

[0057] Step S0: Build a test platform, such as... Figure 2 As shown, the test platform includes an environmental test chamber 3, a wire inlet terminal 13, a wire outlet terminal 14, a simulated power supply 15, and a terminal computer 16.

[0058] The environmental test chamber 3 contains a transformer casting winding 12. Two environmental mist controllers 1 and 2 are located at the top of the environmental test chamber 3. These controllers spray mist onto the environmental test chamber 3. Four partial discharge ultrasonic monitors 4, 5, 6, and 7 are sequentially installed on the four walls of the environmental test chamber 3. These monitors are electrically connected to a terminal computer 16 via a wire outlet terminal 14. The monitors are used to acquire partial discharge signals from the transformer casting winding 12. Four thermal imaging monitors 8, 9, 10, and 11 are sequentially installed on the four walls of the environmental test chamber 3. These monitors are electrically connected to the terminal computer 16 via a wire outlet terminal 14. The thermal imaging monitors are used to acquire the temperature of the transformer casting winding 12 and the interior of the environmental test chamber 3.

[0059] The analog power supply 15 is electrically connected to the transformer casting winding 12 through the wire inlet terminal 13, and is used to inject test current into the transformer casting winding 12.

[0060] In one specific embodiment, step S1 specifically includes:

[0061] Three uniformly increasing test currents, denoted as I1, I2, and I3, are sequentially injected into the transformer's cast windings, where I1 = I... n I2 = 1.1I n I3 = 1.2I n I n This indicates the rated current of the transformer cast winding. Each time a test current is injected, the transformer cast winding is subjected to 50 aging cycle tests. The aging cycle test includes sequentially spraying salt spray onto the transformer cast winding for 1 hour, spraying water mist for 2 hours, and stopping spraying for 3 hours.

[0062] The above is a detailed description of an embodiment of a method for evaluating the anti-aging performance of cast insulation layer of dry-type transformer provided by the present invention. The following is a detailed description of an embodiment of a system for evaluating the anti-aging performance of cast insulation layer of dry-type transformer provided by the present invention.

[0063] For easier understanding, please refer to Figure 3 The present invention provides an evaluation system for the anti-aging performance of cast insulation layers in dry-type transformers, comprising:

[0064] The current injection module 100 is used to inject multiple uniformly increasing test currents into the transformer casting winding in sequence. Each injection of test current performs multiple aging cycle tests on the transformer casting winding. The aging cycle test includes sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding.

[0065] The acquisition module 200 is used to acquire the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test.

[0066] The first calculation module 300 is used to calculate the aging factors corresponding to the multiple uniformly increasing test currents injected, based on the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test, through a first preset formula.

[0067] The second calculation module 400 is used to calculate the anti-aging performance evaluation factor according to the aging factors corresponding to multiple uniformly increasing test currents through a second preset formula.

[0068] Evaluation module 500 is used to compare the anti-aging performance evaluation factor with the preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding based on the comparison result.

[0069] In a specific implementation example, this system also includes a build module for building a test platform, such as... Figure 2 As shown, the test platform includes an environmental test chamber 3, a wire inlet terminal 13, a wire outlet terminal 14, a simulated power supply 15, and a terminal computer 16.

[0070] The environmental test chamber 3 contains a transformer casting winding 12. Two environmental mist controllers 1 and 2 are located at the top of the environmental test chamber 3. These controllers spray mist onto the environmental test chamber 3. Four partial discharge ultrasonic monitors 4, 5, 6, and 7 are sequentially installed on the four walls of the environmental test chamber 3. These monitors are electrically connected to a terminal computer 16 via a wire outlet terminal 14. The monitors are used to acquire partial discharge signals from the transformer casting winding 12. Four thermal imaging monitors 8, 9, 10, and 11 are sequentially installed on the four walls of the environmental test chamber 3. These monitors are electrically connected to the terminal computer 16 via a wire outlet terminal 14. The thermal imaging monitors are used to acquire the temperature of the transformer casting winding 12 and the interior of the environmental test chamber 3.

[0071] The analog power supply 15 is electrically connected to the transformer casting winding 12 through the wire inlet terminal 13, and is used to inject test current into the transformer casting winding 12.

[0072] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0073] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0074] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0075] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the anti-aging performance of cast insulation layers in dry-type transformers, characterized in that, Includes the following steps: S1. By sequentially injecting multiple uniformly increasing test currents into the transformer casting winding, and performing multiple aging cycle tests on the transformer casting winding each time a test current is injected, the aging cycle tests include sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding. S2. Obtain the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test. S3. Based on the number of cycles in which the partial discharge signal reached its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating ambient temperature in each aging cycle test, the aging factors corresponding to the injected uniformly increasing test currents are calculated using a first preset formula; the first preset formula is: In the formula, This represents the aging factor of the j-th injected test current. This represents the j-th injected test current, where j=1,2,3. This indicates the cycle number in which the highest amplitude of the partial discharge signal occurred out of 50 aging cycle tests. This indicates the highest amplitude of the partial discharge signal observed during 50 aging cycle tests. This indicates the number of partial discharge signals corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. This indicates the hot spot temperature of the transformer cast winding corresponding to the periodic test at which the partial discharge signal reaches its highest amplitude. This indicates the ambient temperature corresponding to the periodic test when the highest amplitude of the partial discharge signal occurred. This indicates the temperature rise limit of the thermal insulation class of the cast insulation material for the transformer cast windings. This indicates the highest amplitude of the partial discharge signal observed during the first aging cycle test. This indicates the number of times partial discharge signals appeared during the first aging cycle test. This indicates the hot spot temperature of the transformer casting winding during the first aging cycle test. This indicates the ambient temperature of the transformer casting winding during the first aging cycle test. This indicates the highest amplitude of the partial discharge signal observed during the 50th aging cycle test. This indicates the number of times partial discharge signals appeared during the 50th aging cycle test. This indicates the hot spot temperature of the transformer cast winding during the 50th aging cycle test. This indicates the ambient temperature of the transformer casting winding during the 50th aging cycle test. This represents the highest amplitude of the partial discharge signal observed during the i-th aging cycle test. This indicates the number of times a partial discharge signal appears during the i-th aging cycle test. This represents the hot spot temperature of the transformer casting winding during the i-th aging cycle test. This represents the ambient temperature of the transformer casting winding during the i-th aging cycle test; S4. Calculate the anti-aging performance evaluation factor based on the aging factors corresponding to multiple uniformly increasing test currents using a second preset formula; the second preset formula is: In the formula, η est Indicates the anti-aging performance evaluation factor; S5. Compare the anti-aging performance evaluation factor with the preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding based on the comparison result.

2. The method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer according to claim 1, characterized in that, Before step S1, the following are included: Step S0: Construct a test platform, which includes an environmental test chamber, wire inlet terminals, wire outlet terminals, a simulated power supply, and a terminal computer; The environmental test chamber contains the transformer casting winding. Two environmental mist controllers are located at the top of the environmental test chamber, used to spray mist into the chamber. Four partial discharge ultrasonic monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to a terminal computer via a wire outlet terminal. These monitors are used to acquire partial discharge signals from the transformer casting winding. Four thermal imaging monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to the terminal computer via a wire outlet terminal. These monitors are used to acquire the temperature of the transformer casting winding and the interior of the environmental test chamber. The simulated power supply is electrically connected to the transformer casting winding through the wire inlet terminal, and is used to inject test current into the transformer casting winding.

3. The method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer according to claim 1, characterized in that, Step S1 specifically includes: Three uniformly increasing test currents, denoted as I1, I2, and I3, are sequentially injected into the transformer's cast windings, where I1 = I... n I2=1.1I n I3 = 1.2I n I n The rated current of the transformer cast winding is indicated. Each time a test current is injected, the transformer cast winding is subjected to 50 aging cycle tests. The aging cycle test includes sequentially spraying salt spray onto the transformer cast winding for 1 hour, spraying water spray for 2 hours, and stopping spraying for 3 hours.

4. The method for evaluating the anti-aging performance of the cast insulation layer of a dry-type transformer according to claim 1, characterized in that, Step S5 specifically includes: Compare the anti-aging performance evaluation factor with 1. If 0 < η est If ≤1, it indicates that the anti-aging performance of the transformer cast winding insulation layer is good; if 1 < η est This indicates that the anti-aging performance of the transformer's cast winding insulation layer is poor.

5. A system for evaluating the anti-aging performance of cast insulation layers in dry-type transformers, characterized in that, include: The current injection module is used to inject multiple uniformly increasing test currents into the transformer casting winding in sequence. Each injection of test current performs multiple aging cycle tests on the transformer casting winding. The aging cycle tests include sequentially spraying salt spray, spraying water spray, and stopping spraying onto the transformer casting winding. The acquisition module is used to acquire the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating environment temperature in each aging cycle test. The first calculation module is used to calculate the aging factors corresponding to multiple uniformly increasing test currents injected, based on the number of cycles in which the partial discharge signal reaches its highest amplitude during multiple aging cycle tests of the transformer cast winding, the number of partial discharge signals in each aging cycle test, the highest amplitude of the partial discharge signal in each aging cycle test, the winding hot spot temperature in each aging cycle test, and the operating ambient temperature in each aging cycle test, using a first preset formula; the first preset formula is: In the formula, This represents the aging factor of the j-th injected test current. This represents the j-th injected test current, where j=1,2,3. This indicates the cycle number in which the highest amplitude of the partial discharge signal occurred out of 50 aging cycle tests. This indicates the highest amplitude of the partial discharge signal observed during 50 aging cycle tests. This indicates the number of partial discharge signals corresponding to the periodic test at which the highest amplitude of the partial discharge signal occurred. This indicates the hot spot temperature of the transformer cast winding corresponding to the periodic test at which the partial discharge signal reaches its highest amplitude. This indicates the ambient temperature corresponding to the periodic test when the highest amplitude of the partial discharge signal occurred. This indicates the temperature rise limit of the thermal insulation class of the cast insulation material for the transformer cast windings. This indicates the highest amplitude of the partial discharge signal observed during the first aging cycle test. This indicates the number of times partial discharge signals appeared during the first aging cycle test. This indicates the hot spot temperature of the transformer casting winding during the first aging cycle test. This indicates the ambient temperature of the transformer casting winding during the first aging cycle test. This indicates the highest amplitude of the partial discharge signal observed during the 50th aging cycle test. This indicates the number of times partial discharge signals appeared during the 50th aging cycle test. This indicates the hot spot temperature of the transformer cast winding during the 50th aging cycle test. This indicates the ambient temperature of the transformer casting winding during the 50th aging cycle test. This represents the highest amplitude of the partial discharge signal observed during the i-th aging cycle test. This indicates the number of times a partial discharge signal appears during the i-th aging cycle test. This represents the hot spot temperature of the transformer casting winding during the i-th aging cycle test. This represents the ambient temperature of the transformer casting winding during the i-th aging cycle test; The second calculation module is used to calculate the anti-aging performance evaluation factor based on the aging factors corresponding to multiple uniformly increasing test currents using a second preset formula; the second preset formula is: In the formula, η est Indicates the anti-aging performance evaluation factor; The evaluation module is used to compare the anti-aging performance evaluation factor with a preset factor threshold, and evaluate the anti-aging performance of the transformer cast winding based on the comparison result.

6. The evaluation system for the anti-aging performance of the cast insulation layer of a dry-type transformer according to claim 5, characterized in that, It also includes a building module for building a test platform, which includes an environmental test chamber, wire inlet terminals, wire outlet terminals, a simulated power supply, and a terminal computer; The environmental test chamber contains the transformer casting winding. Two environmental mist controllers are located at the top of the environmental test chamber, used to spray mist into the chamber. Four partial discharge ultrasonic monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to a terminal computer via a wire outlet terminal. These monitors are used to acquire partial discharge signals from the transformer casting winding. Four thermal imaging monitors are sequentially installed on the four walls of the environmental test chamber, electrically connected to the terminal computer via a wire outlet terminal. These monitors are used to acquire the temperature of the transformer casting winding and the interior of the environmental test chamber. The simulated power supply is electrically connected to the transformer casting winding through the wire inlet terminal, and is used to inject test current into the transformer casting winding.

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