Vacuum drying system and control method

Abstract

The invention provides a vacuum drying system and a control method, and relates to the technical field of vacuum drying, in the vacuum drying system, a vacuum drying furnace is provided with a containing cavity, the containing cavity is used for containing a transformer body to be dried and a reference sample, and weighing equipment, a heating piece, a pressure detection piece and a temperature detection piece are all arranged in the containing cavity; the vacuum pump and the containing cavity are communicated and are both in signal connection with the control unit, and in addition, the reference sample is arranged on the weighing device and used for obtaining real-time weight data of the reference sample. On one hand, the vacuum drying system dries the transformer body to be dried in a physical drying mode, the transformer body cannot react with any substance, and the application range is wide. And on the other hand, the weight change speed of the to-be-dried transformer body can be judged according to the setting of the reference sample and the real-time detection of the weight of the reference sample, and the drying treatment rate of the vacuum drying system is adjusted, so that the risk that an insulating layer or an insulating part on the to-be-dried transformer body is cracked by sun is reduced.

Description

Technical Field

[0001] This application relates to the field of vacuum drying technology, and in particular to a vacuum drying system and control method. Background Technology

[0002] In power systems, transformers are important equipment for stepping up and down voltage. Before a transformer is put into operation, the transformer body needs to be dried to prevent moisture from damaging the insulation components and affecting the insulation performance of the transformer.

[0003] In related technologies, transformers using silicon steel cores employ a kerosene vapor-phase drying process during the drying process. High-temperature kerosene vapor is used as the heat transfer medium to heat the transformer body, causing moisture to evaporate and be carried away by the kerosene vapor, thus achieving the drying process. Transformers using amorphous alloy wound cores have a cured insulating adhesive coated on the core as an insulating layer. Kerosene can chemically react with this cured insulating adhesive, causing it to melt and affecting the core's insulation performance.

[0004] Therefore, the kerosene vapor phase drying process has a narrow applicable range in related technologies. Summary of the Invention

[0005] This application provides a vacuum drying system and control method, aiming to solve the technical problem that the kerosene vapor phase drying process is not suitable for drying the body of amorphous alloy wound core transformers, resulting in a narrow range of applications.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] The first aspect of this application provides a vacuum drying system, comprising:

[0008] Control unit;

[0009] A vacuum drying oven having a accommodating cavity for accommodating the transformer body to be dried and a reference sample;

[0010] A weighing device is disposed within the accommodating cavity and is signal-connected to the control unit. The reference sample is disposed on the weighing device to acquire real-time weight data of the reference sample.

[0011] A heating element is disposed within the accommodating cavity and is signal-connected to the control unit;

[0012] A vacuum pump is connected to the accommodating cavity and signal-connected to the control unit.

[0013] A pressure detection element is disposed within the accommodating cavity and is signal-connected to the control unit;

[0014] A temperature sensing element is disposed within the accommodating cavity and is signal-connected to the control unit.

[0015] In some embodiments, the weighing device includes one of a ceramic sensor, a quartz sensor, and a metal foil strain gauge; and / or,

[0016] The pressure sensing element includes one of a lithium niobate piezoelectric pressure sensor, a quartz piezoelectric pressure sensor, and a fiber optic pressure sensor; and / or,

[0017] The temperature detection device includes one of a thermocouple temperature sensor, an infrared temperature sensor, and a fiber optic temperature sensor.

[0018] In some embodiments, the heating element is one of a heating coil and a heating tube, and the heating element is spirally arranged along the peripheral wall of the accommodating cavity.

[0019] In some embodiments, the vacuum drying system further includes a fan disposed within the accommodating cavity and signal-connected to the control unit.

[0020] The vacuum drying system provided in this application embodiment, by setting up a weighing device, a heating element, a vacuum pump, a pressure detection element, and a temperature detection element on the vacuum drying furnace of the vacuum drying system, and connecting the weighing device, heating element, vacuum pump, pressure detection element, and temperature detection element to the control unit respectively, allows the temperature, suction pressure, and weight of the reference sample in the vacuum drying furnace to be monitored in real time, and the temperature and suction pressure in the vacuum drying furnace to be adjusted in real time. This allows for control of the drying speed of the transformer body to be dried and the reference sample set in the vacuum drying furnace, thereby controlling the rate of weight change of the transformer body to be dried and the reference sample.

[0021] On the one hand, the vacuum drying system uses heating and vacuuming to dry the transformer body. This process is a physical drying method and will not react with any substances on the transformer body, making it widely applicable.

[0022] On the other hand, if the transformer body to be dried and the reference sample lose water too quickly, it will cause the insulation layer or insulating components on them to crack. If the transformer body to be dried and the reference sample lose water too slowly, it will reduce the drying efficiency of the vacuum drying system. Therefore, a reference sample is set up, and the drying speed of the vacuum drying system is adjusted according to the real-time weight data of the reference sample. This improves the drying efficiency of the vacuum system while reducing the risk of cracking of the insulation layer and insulating components on the transformer body to be dried. In addition, the size of the weighing device corresponding to the reference sample should be smaller than the size of the weighing device set for the transformer body to be dried, thereby reducing the space occupied by the load-bearing device in the accommodating cavity and thus reducing the space occupied by the entire vacuum drying system.

[0023] A second aspect of this application provides a control method for a vacuum drying system, applicable to the vacuum drying system described in any of the above claims, the control method comprising:

[0024] Step S01: Start the heating element and acquire the real-time weight data of the reference sample in real time, so as to adjust the heating rate of the heating element according to the acquired real-time weight data until the ambient temperature in the accommodating cavity reaches the preset temperature threshold.

[0025] Step S02: Start the vacuum pump and acquire the real-time weight data of the reference sample in real time, so as to adjust the suction speed of the vacuum pump according to the acquired real-time weight data until the vacuum degree in the accommodating cavity reaches the preset pressure threshold.

[0026] Step S03: Obtain the real-time weight data of the current reference sample to determine whether the weight data of the reference sample has reached the preset weight threshold;

[0027] Step S04: If not, repeat steps S01 and S02 until the weight data of the reference sample reaches the preset weight threshold.

[0028] In some embodiments, in step S01, the range of the preset temperature threshold is 100~110℃.

[0029] In some embodiments, in step S02, the range of the preset pressure threshold is 0.01~0.1kPa.

[0030] In some embodiments, in step S03, the ratio of the preset weight threshold to the initial weight value of the reference sample is in the range of (84~86):100.

[0031] In some embodiments, the vacuum drying system includes a fan disposed within the accommodating cavity and signal-connected to the control unit. Step S01 specifically includes:

[0032] Simultaneously with activating the heating element, the fan is also activated, and real-time weight data of the reference sample is acquired.

[0033] Based on the acquired real-time weight data, adjust at least one of the heating rate of the heating element and the air outlet speed of the fan until the ambient temperature inside the accommodating cavity reaches the preset temperature threshold.

[0034] In some embodiments, step S02 specifically includes:

[0035] Simultaneously with starting the vacuum pump, the heating element is activated, and the real-time weight data of the reference sample is acquired.

[0036] Based on the acquired real-time weight data, at least one of the vacuum pump's suction speed and the heating element's heating temperature is adjusted until the vacuum level in the accommodating cavity reaches a preset pressure threshold.

[0037] The control method of the vacuum drying system provided in this application embodiment has the same beneficial effects as the vacuum drying system provided in the above embodiments, and will not be repeated here.

[0038] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the vacuum drying system and control method provided by the embodiments of this application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart illustrating a control method for a vacuum drying system provided in an embodiment of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] In power systems, transformers are important equipment for stepping up and down voltage. Before a transformer is put into operation, the transformer body needs to be dried to prevent moisture from damaging the insulation components and affecting the insulation performance of the transformer.

[0043] In related technologies, transformers using silicon steel cores employ a kerosene vapor-phase drying process during the drying process. High-temperature kerosene vapor is used as the heat transfer medium to heat the transformer body, causing moisture to evaporate and be carried away by the kerosene vapor, thus achieving the drying process. Transformers using amorphous alloy wound cores have a cured insulating adhesive coated on the core as an insulating layer. Kerosene can chemically react with this cured insulating adhesive, causing it to melt and affecting the core's insulation performance.

[0044] Therefore, the kerosene vapor phase drying process has a narrow applicable range in related technologies.

[0045] To overcome the aforementioned technical problems, this application provides a vacuum drying system and control method. The content of this application will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can more clearly and thoroughly understand the content of this application.

[0046] First, this application provides a vacuum drying system, including a vacuum drying oven, a weighing device, and a control unit.

[0047] The vacuum drying oven has a accommodating cavity for holding the transformer body to be dried and a reference sample. A weighing device is located inside the accommodating cavity and is signal-connected to the control unit. The reference sample is placed on the weighing device to obtain real-time weight data of the reference sample.

[0048] It should be noted that when using a vacuum drying oven to dry the transformer body, the reference sample is placed into the receiving cavity simultaneously with the transformer body. The reference sample shares some components with the transformer body. For example, when the transformer body is a three-dimensional wound core transformer made of amorphous alloy, the reference sample can be a portion of the amorphous alloy strip used to wind the core, coated with cured insulating adhesive. This serves as a reference group for the transformer body. Of course, this portion of the amorphous alloy strip can be the thickest part of the amorphous alloy strip used to wind the core, ensuring a larger initial weight for accurate measurement of weight changes during the vacuum drying process.

[0049] The logic behind setting up a reference sample here is that before a transformer is put into formal use, it contains insulating layers or components, such as the cured insulating adhesive coated on the core. If the transformer contains moisture, it will affect the insulation strength of these insulating layers or components, making the insulation between windings and between windings and the core prone to breakdown and short circuits. Therefore, the transformer body needs to be dried. For example, in an oil-immersed transformer, the transformer body is dried before oil is added. After drying, oil is added. During the drying process, the moisture on the transformer body gradually disappears over time, thus gradually reducing its weight.

[0050] Therefore, the weight of the transformer body to be dried is an indicator of whether the drying process is complete. However, considering the large size and weight of the transformer body, directly weighing it in the vacuum drying oven would require a large weighing device within the cavity, thus increasing the overall size of the vacuum drying oven. Therefore, a reference sample, identical to some components of the transformer body, is placed in the vacuum drying oven simultaneously. The drying progress of the reference sample is the same as that of the transformer body, and the weighing device is only used for real-time weighing of the reference sample. Because the reference sample is smaller, the volume of the cavity occupied by the weighing device is reduced, thereby reducing the overall size of the vacuum drying oven.

[0051] In some embodiments, the weighing device may be an electronic balance, an electronic platform scale, etc. For example, the housing material of the weighing device is made of carbon steel, low alloy steel, stainless steel, etc., and the weight sensor of the weighing device includes one of ceramic sensor, quartz sensor, and metal foil strain gauge, all of which are high temperature resistant weight sensors.

[0052] In addition, the vacuum drying system also includes heating elements, a vacuum pump, pressure detection elements, and temperature detection elements.

[0053] The heating element is located inside the accommodating cavity and is connected to the control unit for heating the accommodating cavity in the vacuum drying oven. This heats the environment inside the accommodating cavity, or the environment around the transformer to be dried and the reference sample, thereby heating the transformer to be dried and the reference sample. This causes the liquid water on the transformer to be dried and the reference sample to evaporate and form gaseous water, which then escapes from the transformer to be dried and the reference sample in the form of gaseous water.

[0054] For example, the heating element is either a heating coil or a heating tube, and the heating element is spirally arranged along the peripheral wall of the accommodating cavity, thereby increasing the contact area with the accommodating cavity and improving the uniformity of heating the environment in the accommodating cavity.

[0055] The vacuum pump is connected to the accommodating cavity and signal-connected to the control unit to perform vacuuming in the accommodating cavity of the vacuum drying oven, thereby extracting the air containing gaseous water in the accommodating cavity to the outside of the vacuum drying oven, thus completely separating the moisture on the transformer body to be dried and the reference sample.

[0056] The pressure detection element is installed inside the accommodating cavity and connected to the control unit signal to detect the pressure inside the accommodating cavity. That is, it detects the pressure data in real time during the vacuum pump's evacuation process of the accommodating cavity, so as to provide data feedback for judging the speed of the vacuum pump's suction.

[0057] For example, the pressure sensing element includes one of a lithium niobate piezoelectric pressure sensor, a quartz piezoelectric pressure sensor, and a fiber optic pressure sensor, all of which are high-temperature resistant pressure sensors.

[0058] The temperature sensing element is installed inside the accommodating cavity and connected to the control unit signal to detect the temperature inside the accommodating cavity. That is, it detects the temperature data of the heating element during the heating process of the accommodating cavity in real time, so as to provide data feedback for judging the heating speed of the heating element.

[0059] For example, the temperature sensing device includes one of a thermocouple temperature sensor, an infrared temperature sensor, and a fiber optic temperature sensor, all of which are high-temperature resistant temperature sensors.

[0060] Furthermore, the vacuum drying system also includes a blower, which is installed inside the accommodating cavity and connected to the control unit via a signal to purge the air in the accommodating cavity, allowing the air in the accommodating cavity to circulate. The combined use of the blower and the heating element allows the environment in the accommodating cavity to be heated more quickly and more evenly.

[0061] Additionally, for example, the control unit includes an interface module, a transmission module, a processing module, and a display. The interface module has multiple interfaces, which are used to make electrical signal connections with the weighing equipment, heating element, vacuum pump, pressure detection element, temperature detection element, and fan, respectively. Of course, the weighing equipment, heating element, vacuum pump, pressure detection element, temperature detection element, and fan all have corresponding interfaces. The transmission module is used to transmit each signal to the processing module to convert the electrical signals into data signals, and then display the data on the display.

[0062] Furthermore, the display includes a display module and a control module. The display module can show real-time weight data detected by the weighing equipment, heating power of the heating element, rotation speed of the vacuum pump, real-time pressure data detected by the pressure sensor, real-time temperature data detected by the temperature sensor, and the power of the corresponding motor of the blower. The control module can be a manual input module for inputting the heating power of the heating element, the rotation speed of the vacuum pump, and the power of the corresponding motor of the blower to adjust these parameters in real time. Alternatively, the control module can be a knob for adjusting the heating power of the heating element, the rotation speed of the vacuum pump, and the rotation speed of the blower. By rotating these knobs, the heating power of the heating element, the rotation speed of the vacuum pump, and the rotation speed of the blower are adjusted, thereby controlling the heating rate of the accommodating cavity and the suction rate during vacuuming.

[0063] In this embodiment, by setting up a weighing device, a heating element, a vacuum pump, a pressure detection element, and a temperature detection element on the vacuum drying furnace of the vacuum drying system, and connecting the weighing device, heating element, vacuum pump, pressure detection element, and temperature detection element to the control unit, the temperature, suction pressure, and weight of the reference sample in the vacuum drying furnace can be monitored in real time, and the temperature and suction pressure in the vacuum drying furnace can be adjusted in real time. This allows control over the drying process of the transformer body to be dried and the reference sample placed in the vacuum drying furnace, thereby controlling the rate of weight change of the transformer body to be dried and the reference sample.

[0064] On the one hand, this vacuum drying system uses heating and vacuuming to dry the transformer body. This process is a physical drying method and will not react with any substances on the transformer body, making it widely applicable. On the other hand, if the transformer body and the reference sample lose water too quickly, the insulation layer or insulating components on them will crack. If the water loss is too slow, the drying efficiency of the vacuum drying system will decrease. Therefore, a reference sample is set up, and the drying speed of the vacuum drying system is adjusted based on the real-time weight data of the reference sample. This improves the drying efficiency of the vacuum system while reducing the risk of cracking of the insulation layer and insulating components on the transformer body.

[0065] It should be further explained that if the transformer body and the reference sample lose water too quickly during the drying process, i.e., the weight decreases too rapidly, the insulation layer or insulating components may crack. Conversely, if the water loss is too slow, the drying efficiency of the vacuum drying system will decrease. Therefore, before drying the transformer body and the reference sample, operators must first obtain a standard drying efficiency curve for the reference sample through multiple experiments. This standard drying efficiency curve is the relationship between the weight decrease of the reference sample and time. When the weight change of the reference sample follows this standard drying efficiency curve, the weight decrease rate of the transformer body and the reference sample will not be too fast or too slow. Therefore, the insulation layer will not crack, and the drying efficiency will not be too low.

[0066] Of course, the standard drying efficiency curves for reference samples of transformers made of different materials will be different.

[0067] Therefore, during the vacuum drying process of the transformer body to be dried and the reference sample, the heating rate and suction pressure of the vacuum drying furnace can be adjusted by real-time detection of the weight of the reference sample and comparison with the standard drying efficiency curve. This ensures that the real-time weight change rate of the reference sample in the vacuum drying furnace is consistent with the change efficiency of the standard drying efficiency curve at the same moment, thereby avoiding the transformer body to be dried losing water too quickly or too slowly.

[0068] In addition, such as Figure 1 As shown, this application provides a control method for a vacuum drying system, applicable to any of the vacuum drying systems described above. The control method includes:

[0069] Step S01: Start the heating element and acquire the real-time weight data of the reference sample in real time. Adjust the heating rate of the heating element according to the acquired real-time weight data until the ambient temperature in the accommodating cavity reaches the preset temperature threshold.

[0070] Step S02: Start the vacuum pump and acquire the real-time weight data of the reference sample. Adjust the suction speed of the vacuum pump according to the acquired real-time weight data until the vacuum level in the accommodative cavity reaches the preset pressure threshold.

[0071] Step S03: Obtain the real-time weight data of the current reference sample to determine whether the weight data of the reference sample has reached the preset weight threshold;

[0072] Step S04: If not, repeat steps S01 and S02 until the weight data of the reference sample reaches the preset weight threshold.

[0073] Step S01 involves heating the transformer body to be dried and the reference sample in the accommodating cavity from room temperature to a preset temperature threshold to evaporate the liquid water in the insulation layer of the transformer body to be dried and the reference sample into gaseous water, thereby removing the water from the transformer body to be dried and the reference sample. Step S02 involves evacuating the environment in the accommodating cavity to draw the air in the accommodating cavity containing gaseous water out of the accommodating cavity, thereby completely separating the water from the transformer body to be dried and the reference sample.

[0074] It should be noted that the standard drying efficiency curve of the reference sample is also obtained through the above steps S01 to S04, in which the reference sample is placed in a vacuum drying oven for drying treatment, so as to obtain the limit value of the heating rate of the heating element in step S01 and the limit value of the vacuum pump suction rate in step S02. Combined with the overall drying time of the reference sample, i.e. the drying efficiency, the standard drying efficiency curve is formed.

[0075] Of course, since the transformer body to be dried incorporates different materials, multiple reference samples of different materials can be set up during the process of obtaining the standard drying efficiency curve of the reference sample. These samples are then dried simultaneously in a vacuum drying system. Through steps S01 to S04, by combining the temperature rise limit, vacuum pump suction speed limit, and drying efficiency of different reference samples, each reference sample is ensured to avoid cracking during the drying process, thus forming a corresponding standard drying efficiency curve for each reference sample of different materials. During the drying process of the transformer body to be dried, one reference sample and its corresponding standard drying efficiency curve are selected and placed simultaneously in the accommodating cavity with the transformer body to be dried.

[0076] In step S01, for example, the preset temperature threshold range is 100~110°C, which takes into account the temperature range that the transformer body to be dried and the insulation components in the reference sample, such as the cured insulating adhesive, can withstand.

[0077] In step S01, if the real-time weight change rate of the reference sample at a certain moment is greater than the weight change rate in the standard drying efficiency curve at that moment, it indicates that the transformer body to be dried and the reference sample are losing water too quickly at that moment, and the insulation components on them are at risk of cracking. Therefore, by reducing the power of the heating element, the heating rate is reduced, thereby decreasing the rate at which moisture is removed from the transformer body to be dried and the reference sample, i.e., reducing the weight reduction rate of the transformer body to be dried and the reference sample, thus reducing the risk of cracking of the insulation layer or insulation components. If the real-time weight change rate of the reference sample at a certain moment is less than the weight change rate in the standard drying efficiency curve at that moment, it indicates that the transformer body to be dried and the reference sample are losing water too slowly at that moment, and the drying efficiency is low. Therefore, by increasing the power of the heating element, the heating rate is increased, thereby increasing the rate at which moisture is removed from the transformer body to be dried and the reference sample, i.e., accelerating the weight reduction rate of the transformer body to be dried and the reference sample, thus improving the drying efficiency of the vacuum drying oven.

[0078] In some embodiments, in step S02, for example, the range of the preset pressure threshold is 0.01~0.1kPa.

[0079] In step S02, similarly, if the real-time weight change rate of the reference sample at a certain moment is greater than the weight change rate in the standard drying efficiency curve at that moment, it indicates that the transformer body to be dried and the reference sample are losing water too quickly at that moment, and the insulation components on them are at risk of cracking. Therefore, by reducing the suction speed of the vacuum pump, the rate at which moisture completely separates from the transformer body to be dried and the reference sample is slowed down, i.e., the weight reduction rate of the transformer body to be dried and the reference sample is reduced, thereby reducing the risk of cracking of the insulation layer or insulation components. If the real-time weight change rate of the reference sample at a certain moment is less than the weight change rate in the standard drying efficiency curve at that moment, it indicates that the transformer body to be dried and the reference sample are losing water too slowly at that moment, and the drying efficiency is low. Therefore, by increasing the suction speed of the vacuum pump, the rate at which moisture completely separates from the transformer body to be dried and the reference sample is increased, i.e., the weight reduction rate of the transformer body to be dried and the reference sample is accelerated, thereby improving the drying efficiency of the vacuum drying oven.

[0080] In some embodiments, in step S03, for example, the ratio of the preset weight threshold to the initial weight value of the reference sample is in the range of (84~86):100. That is, when the weight reduction of the reference sample during the drying process in the vacuum drying oven accounts for 14%~16% of the initial weight value of the reference sample, the drying process of the transformer body to be dried can be stopped, so as to indicate the end of the drying process in the vacuum drying system.

[0081] In addition, in some embodiments, the vacuum drying system includes a fan disposed within the accommodating cavity and signal-connected to the control unit. Step S01 specifically includes:

[0082] Simultaneously with starting the heating element, the fan is also started, and real-time weight data of the reference sample is acquired.

[0083] Based on the acquired real-time weight data, adjust at least one of the heating element's heating rate and the fan's airflow rate until the ambient temperature inside the containment cavity reaches the preset temperature threshold.

[0084] By combining a fan and a heating element, the real-time weight change rate of the reference sample can be obtained based on its real-time weight data. This rate is then compared with the weight change rate in the standard drying efficiency curve at that moment. By adjusting the heating power of the heating element or the power of the corresponding motor of the fan, or by adjusting both the heating power of the heating element and the power of the corresponding motor of the fan, the weight change rate of the reference sample can be controlled, ensuring that the weight change of the reference sample extends along the standard drying efficiency curve. The simultaneous setup of the fan and heating element in the vacuum drying system increases the adjustable method and range of the heating rate in the accommodating cavity during step S01, thereby further improving the accuracy of temperature control in the accommodating cavity and consequently improving the accuracy of weight control for the reference sample.

[0085] In some embodiments, step S02 specifically includes:

[0086] Simultaneously with starting the vacuum pump, the heating element is activated, and real-time weight data of the reference sample is acquired.

[0087] Based on the acquired real-time weight data, adjust at least one of the vacuum pump's suction speed and the heating element's heating temperature until the vacuum level in the accommodating cavity reaches the preset pressure threshold.

[0088] In step S02, during the evacuation of the air in the accommodating cavity using a vacuum pump, a heating element is used to maintain a high temperature of the air in the accommodating cavity, preventing the gaseous water in the accommodating cavity from converting into liquid water. In step S02, when the real-time weight change rate of the reference sample needs adjustment, this can be achieved by adjusting the rotation speed of the vacuum pump or the heating power of the heating element, or both. This increases the adjustability and range of the weight change of the reference sample in the accommodating cavity during step S02, thereby further improving the accuracy of weight control for the reference sample.

[0089] In addition, in some embodiments, during the drying process of the transformer body to be dried and the reference sample in the vacuum drying system, the control method used includes, based on the judgment in step S03 and the limitation in step S04, multiple cycles of steps S01 and S02, including but not limited to once, twice, three times, four times, five times, six times, etc., until the weight data of the reference sample reaches the preset weight threshold, that is, both the transformer body to be dried and the reference sample have reached the required degree of drying.

[0090] Furthermore, after each step S02 is completed, the air drawn out from the accommodating cavity can be cooled to separate the dry air and liquid water. Before performing step S01 again, the environment in the accommodating cavity needs to be purged. This purging process can be completed by slowly introducing the separated dry air into the accommodating cavity.

[0091] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0092] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0093] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0094] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A vacuum drying system, characterized in that, include: Control unit; A vacuum drying oven having a accommodating cavity for accommodating the transformer body to be dried and a reference sample; A weighing device is disposed within the accommodating cavity and is signal-connected to the control unit. The reference sample is disposed on the weighing device to acquire real-time weight data of the reference sample. A heating element is disposed within the accommodating cavity and is signal-connected to the control unit; A vacuum pump is connected to the accommodating cavity and signal-connected to the control unit. A pressure detection element is disposed within the accommodating cavity and is signal-connected to the control unit; A temperature sensing element is disposed within the accommodating cavity and is signal-connected to the control unit.

2. The vacuum drying system according to claim 1, characterized in that, The weighing device includes one of a ceramic sensor, a quartz sensor, and a metal foil strain gauge; and / or, The pressure sensing element includes one of a lithium niobate piezoelectric pressure sensor, a quartz piezoelectric pressure sensor, and a fiber optic pressure sensor; and / or, The temperature detection device includes one of a thermocouple temperature sensor, an infrared temperature sensor, and a fiber optic temperature sensor.

3. The vacuum drying system according to claim 1, characterized in that, The heating element is either a heating coil or a heating tube, and the heating element is spirally arranged along the circumferential wall of the accommodating cavity.

4. The vacuum drying system according to any one of claims 1-3, characterized in that, The vacuum drying system also includes a fan, which is disposed inside the accommodating cavity and is signal-connected to the control unit.

5. A control method for a vacuum drying system, applicable to the vacuum drying system as described in any one of claims 1-4, characterized in that, The control method includes: Step S01: Start the heating element and acquire the real-time weight data of the reference sample in real time, so as to adjust the heating rate of the heating element according to the acquired real-time weight data until the ambient temperature in the accommodating cavity reaches the preset temperature threshold. Step S02: Start the vacuum pump and acquire the real-time weight data of the reference sample in real time, so as to adjust the suction speed of the vacuum pump according to the acquired real-time weight data until the vacuum degree in the accommodating cavity reaches the preset pressure threshold. Step S03: Obtain the real-time weight data of the current reference sample to determine whether the weight data of the reference sample has reached the preset weight threshold; Step S04: If not, repeat steps S01 and S02 until the weight data of the reference sample reaches the preset weight threshold.

6. The control method according to claim 5, characterized in that, In step S01, the range of the preset temperature threshold is 100~110℃.

7. The control method according to claim 5, characterized in that, In step S02, the preset pressure threshold ranges from 0.01 to 0.1 kPa.

8. The control method according to claim 5, characterized in that, In step S03, the ratio of the preset weight threshold to the initial weight value of the reference sample is in the range of (84~86):

100.

9. The control method according to claim 5, characterized in that, The vacuum drying system includes a fan, which is disposed within the accommodating cavity and is signal-connected to the control unit. Step S01 specifically includes: Simultaneously with activating the heating element, the fan is also activated, and real-time weight data of the reference sample is acquired. Based on the acquired real-time weight data, adjust at least one of the heating rate of the heating element and the air outlet speed of the fan until the ambient temperature inside the accommodating cavity reaches the preset temperature threshold.

10. The control method according to claim 5, characterized in that, Step S02 specifically includes: Simultaneously with starting the vacuum pump, the heating element is activated, and the real-time weight data of the reference sample is acquired. Based on the acquired real-time weight data, adjust at least one of the vacuum pump's suction speed and the heating element's heating temperature until the vacuum level in the accommodating cavity reaches a preset pressure threshold.

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