Oil-immersed transformer operation fault diagnosis and prevention method

Abstract

The invention relates to the technical field of oil-immersed transformers, and provides an oil-immersed transformer operation fault diagnosis and prevention method. The oil-immersed transformer comprises a transformer body and an oil tank, insulating oil is arranged in the oil tank, the transformer body is soaked in the insulating oil, and an air chamber is arranged above the insulating oil. When the oil tank is in a sealed environment, the absolute temperature and the actually measured pressure of the air chamber are collected; determining theoretical pressure according to the absolute temperature and the operation time of the oil-immersed transformer; fault diagnosis is carried out according to the actually measured pressure and the theoretical pressure, the operation fault type of the oil-immersed transformer is determined, and prevention measures corresponding to the operation fault type are executed. According to the invention, low-cost real-time on-line diagnosis can be carried out on the most major operation faults, namely sealing failure, of the oil-immersed transformer, so that the transformer winding is prevented from being burnt down due to the failure of the sealing ring; and meanwhile, the combustion and explosion risks of the oil-immersed transformer are thoroughly prevented.

Description

Technical Field

[0001] This application relates to the field of oil-immersed transformer technology, and in particular to a method for diagnosing and preventing operational faults in oil-immersed transformers. Background Technology

[0002] Transformers are the core of energy conversion and transmission in power systems and are widely used in power grids. They transmit electrical energy from power plants to users, and their normal operation is crucial for the safety and stability of the power system. Based on cooling methods, transformers can be divided into two categories: dry-type transformers and oil-immersed transformers. In oil-immersed transformers, the transformer body (consisting of coils and core) is immersed in a large amount of insulating oil, which effectively isolates and protects the transformer body, resulting in good insulation performance, strong heat dissipation, low manufacturing and maintenance costs, and convenient recycling. This makes them more economical than dry-type transformers and they are widely used in power systems. In related technologies, oil-immersed transformers are inspected for faults according to a fixed testing cycle. For example, for oil-immersed transformers with a capacity of 8MVA or higher but less than 120MVA and a voltage of 66kV or higher but less than 220kV, they are typically inspected once a year. However, this inspection method in related technologies is reactive; by the time the fault detection results are obtained, the fault has already occurred. Summary of the Invention

[0003] This application provides a method for diagnosing and preventing operational faults in oil-immersed transformers. It can perform low-cost, real-time online diagnosis of the most significant operational fault in oil-immersed transformers: seal failure, thereby preventing the transformer windings from burning out due to seal failure. At the same time, it completely prevents the risk of combustion and explosion of oil-immersed transformers.

[0004] This application provides a method for diagnosing and preventing operational faults in an oil-immersed transformer. The oil-immersed transformer includes a transformer body and an oil tank. The oil tank contains insulating oil, and the transformer body is immersed in the insulating oil. An air chamber is located above the insulating oil. The method for diagnosing and preventing operational faults in an oil-immersed transformer includes: When the fuel tank is in a sealed environment, the absolute temperature and measured pressure of the gas chamber are collected; The theoretical pressure is determined based on the absolute temperature and the commissioning time of the oil-immersed transformer. Based on the measured pressure and theoretical pressure, fault diagnosis is performed to determine the type of operational fault in the oil-immersed transformer, and corresponding preventive measures are implemented.

[0005] Optionally, in one embodiment, when the fuel tank is in a sealed environment, collecting the absolute temperature and measured pressure of the gas chamber includes: When an O-ring is installed in the annular groove of the flange of the oil tank, the absolute temperature and measured pressure of the gas chamber are collected.

[0006] Alternatively, in one embodiment, the theoretical pressure is determined according to the following formula: ; in, This represents the theoretical pressure, and K represents a constant. This indicates the normal gas escape rate of an oil-immersed transformer. This indicates the commissioning time of the oil-immersed transformer. This indicates the amount of gas injected into the gas chamber. This indicates absolute temperature.

[0007] Optionally, in one embodiment, fault diagnosis is performed based on measured pressure and theoretical pressure to determine the type of operational fault in the oil-immersed transformer, and corresponding preventive measures are implemented, including: Determine the normal pressure range based on theoretical pressure; If the measured pressure is less than the normal pressure range, the fault type of the oil-immersed transformer is determined to be a seal failure, and a seal inspection prompt message is output so that maintenance personnel can inspect the seal of the oil tank. If the measured pressure is greater than the normal pressure range, the operating fault type of the oil-immersed transformer is determined to be a gas production rate fault. A gas production rate fault troubleshooting prompt message is output so that maintenance personnel can further analyze the insulating oil.

[0008] Optionally, in one embodiment, determining the normal pressure range based on the theoretical pressure includes: The theoretical pressure is corrected according to the preset correction coefficient to obtain the lower limit and upper limit of the theoretical pressure. The normal pressure range is determined based on the theoretical lower pressure limit and the theoretical upper pressure limit.

[0009] Optionally, in one embodiment, before collecting the absolute temperature and measured pressure of the gas chamber, the method further includes: Exhaust the air chamber and inject a non-oxidizing gas into it.

[0010] Optionally, in one embodiment, before determining the theoretical pressure of the gas chamber based on the absolute temperature and the commissioning time of the oil-immersed transformer, the method further includes: Compare the absolute temperature with the normal temperature range; If the absolute temperature is within the normal temperature range, then the theoretical pressure is determined based on the absolute temperature and the commissioning time of the oil-immersed transformer. If the absolute temperature is outside the normal temperature range, a temperature alarm message will be output.

[0011] The fault diagnosis and prevention scheme for oil-immersed transformers provided in this application collects the absolute temperature and measured pressure of the gas chamber when the oil tank is in a sealed environment; determines the theoretical pressure based on the absolute temperature and the commissioning time of the oil-immersed transformer; performs fault diagnosis based on the measured pressure and theoretical pressure to determine the type of operational fault of the oil-immersed transformer, and implements corresponding preventive measures. This scheme does not rely on complex external equipment; it can achieve real-time assessment of the temperature and pressure status of the gas chamber inside the oil tank using only built-in sensors, thereby enabling low-cost online fault diagnosis. Once a fault is detected, an alarm mechanism is triggered in a timely manner to remind maintenance personnel to take preventive measures, effectively preventing the entire transformer from burning out due to the damage of a single sealing ring. This invention creatively proposes a method for diagnosing and preventing operational faults in oil-immersed transformers by grasping the key factors causing operational faults, and discloses the formula for diagnosing and preventing operational faults in oil-immersed transformers for the first time in the world. According to this formula, the absolute pressure inside the transformer chamber is a function of absolute temperature and operating time. Based on the method of this invention, real-time online diagnosis can be performed on oil-immersed transformers when fault signs appear, and faults can be promptly eliminated based on the diagnostic results, preventing fault occurrence and avoiding the pitfalls of reactive repair. This is a pioneering innovation that overcomes the limitations of existing technologies that rely on expensive equipment or periodic testing for fault diagnosis. Furthermore, the injection of non-oxidizing gas into the chamber completely prevents the risk of combustion and explosion in oil-immersed transformers. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of an application environment for the method for diagnosing and preventing operational faults in oil-immersed transformers provided in this application embodiment; Figure 2 This is a flowchart illustrating the method for diagnosing and preventing operational faults in an oil-immersed transformer provided in this application embodiment; Figure 3 This is a schematic diagram of the structure of the oil-immersed transformer in the embodiments of this application. Detailed Implementation

[0014] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0015] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0016] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0017] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0018] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0020] It should be understood that the sequence number of each step in the following embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0021] To illustrate the technical solution of this application, specific embodiments are described below.

[0022] Insulating oil is a hydrocarbon compound, primarily composed of alkanes, cycloalkanes, and aromatics. Pure insulating oil has very high insulation strength, typically reaching 40kV / mm, many times higher than air. Therefore, using insulating oil as insulation can significantly reduce the size of transformers. Furthermore, its good fluidity allows for insulation strength recovery after breakdown, leaving no permanent discharge path, and it can be reused after filtration. Insulating oil also penetrates well into the transformer's interior, filling the entire space, thereby improving withstand voltage. It also provides a dry environment for windings and other solid insulating materials.

[0023] The "small bridge" theory posits that the breakdown of insulating oil is caused by impurities such as moisture, gases, and water-soluble acids, which distort the electric field distribution and lead to a local increase in electric field strength. Specifically, because impurities such as moisture, water-soluble acids, and gases have high dielectric constants, they polarize and orient themselves along the direction of the electric field under its influence, forming conductive "bridges" between the electric fields. Initially, these bridges act as leakage paths, eventually developing into breakdown paths.

[0024] There are two sources of moisture: one is that moisture is absorbed by the fiber paper during the manufacturing and installation process; the other is that moisture from the air environment enters due to seal failure during operation.

[0025] There is only one source of acid in insulating oil: when insulating oil comes into contact with oxygen in the air, it undergoes an oxidation reaction, and the resulting product hydrolyzes to produce free acid.

[0026] Insulating oil is a mixture of hydrocarbon molecules of varying molecular weights, containing CH3, CH2, and CH groups bonded together by C-C bonds. Electrical or thermal faults can cause some of these CH and C-C bonds to break, generating small amounts of reactive hydrogen atoms and unstable hydrocarbon radicals: CH3*, CH2*, CH*, or C*. These hydrogen atoms or radicals rapidly recombine through complex chemical reactions to form hydrogen gas and low-molecular-weight hydrocarbon gases such as methane, ethane, ethylene, and acetylene. In the initial stages of a fault, the formed gases dissolve in the oil.

[0027] When a low-energy fault occurs, such as partial discharge, the weakest bond, CH (33 kJ / mol), breaks through ionic reactions, and most of the hydrogen ions recombine to form hydrogen gas, which accumulates. Breaking the C-C bond requires higher temperatures (more energy), and then the hydrogen ions rapidly recombine to form hydrocarbon gases through C-C (607 kJ / mol), C=C (720 kJ / mol), and C≡C (960 kJ / mol) bonds, requiring progressively higher temperatures and more energy.

[0028] Ethylene is formed at approximately 500°C (higher than the formation temperatures of methane and ethane), while acetylene is generally formed at temperatures between 800°C and 1200°C. Furthermore, as the temperature decreases, the reaction is rapidly inhibited, and acetylene accumulates as a stable product of recombination. Therefore, a large amount of acetylene is produced in the arc of an electric arc. Of course, a small amount of acetylene may also be formed at lower temperatures (below 800°C).

[0029] The inventors of this application discovered that due to seal failure, moisture from the air enters the insulating oil, causing a "bridge" to form and resulting in discharge. Oxygen enters the insulating oil, which oxidizes and hydrolyzes under the action of discharge, producing acid, which intensifies the discharge. Simultaneously, the discharge causes the insulating oil to decompose, producing gases such as hydrogen (H2), methane (CH4), ethane (C2H6), ethylene (C2H4), acetylene (C2H2), carbon monoxide (CO), and carbon dioxide (CO2), which further enhance the discharge. At the same time, in an oxygen-rich environment, the production and accumulation of large amounts of combustible gases such as H2 and C2H2, combined with the occurrence of spark discharge, brings the mixture to its ignition point, creating "perfect" conditions for combustion and explosion, making the risk of combustion and explosion inevitable. Based on this, this application provides a method for diagnosing and preventing operational faults in oil-immersed transformers, aiming to achieve low-cost online fault diagnosis of oil-immersed transformers. It solves the problem of not knowing when the seal will fail. Once the seal fails, it is detected in real time and dealt with immediately, thereby preventing moisture and oxygen from entering the oil tank and preventing the fault from developing. At the same time, injecting non-oxidizing gas can completely prevent the risk of combustion and explosion of oil-immersed transformers.

[0030] Please refer to Figure 1 , Figure 1 This is a schematic diagram illustrating an application environment for the oil-immersed transformer operation fault diagnosis and prevention method provided in this application. As one implementation method, the oil-immersed transformer operation fault diagnosis and prevention method provided in this application can be applied to a computer device, which can be any device such as a desktop computer, server, or industrial control computer equipped with a processor and possessing data processing capabilities.

[0031] An oil-immersed transformer includes a transformer body and an oil tank. The oil tank contains insulating oil, and the transformer body is immersed in the insulating oil. A gas chamber is located above the insulating oil. In some embodiments, computer equipment can collect the absolute temperature and measured pressure of the gas chamber when the oil tank is in a sealed environment; determine the theoretical pressure based on the absolute temperature and the transformer's commissioning time; perform fault diagnosis based on the measured and theoretical pressures to determine the type of operational fault in the oil-immersed transformer; and implement corresponding preventative measures. This achieves low-cost online fault diagnosis for oil-immersed transformers, solving the problem of not knowing when the seal will fail. Once the seal fails, it is detected in real time and dealt with immediately, thus preventing moisture and oxygen from entering the oil tank and preventing fault development. Simultaneously, injecting a non-oxidizing gas can completely prevent the risk of combustion and explosion of the oil-immersed transformer.

[0032] Please refer to Figure 2 , Figure 2 This is a flowchart illustrating a method for diagnosing and preventing operational faults in an oil-immersed transformer, as provided in an embodiment of this application. Please refer to it. Figure 3 An oil-immersed transformer consists of a transformer body and an oil tank. The oil tank contains insulating oil, and the transformer body is immersed in the insulating oil. An air chamber is located above the insulating oil. Figure 2 As shown, the process for diagnosing and preventing operational faults in this oil-immersed transformer can be as follows: In S110, when the oil tank is in a sealed environment, the absolute temperature and measured pressure of the gas chamber are collected.

[0033] As one of the core components of an oil-immersed transformer, the oil tank is an important container for holding the transformer body and insulating oil. The tank body is mostly a rectangular or cylindrical welded structure (large-capacity oil-immersed transformers often use elliptical tanks to enhance pressure resistance), welded from low-carbon steel plates. The inner wall is treated with rust prevention (such as phosphating or coating with insulating varnish) to prevent rust from contaminating the insulating oil. External cooling devices (such as plate radiators or tubular radiators) or cooling fans can be installed on the tank to conduct internal heat to the outside through the tank walls, maintaining the transformer body's temperature stability.

[0034] The transformer body consists of main structures such as iron core and windings. The iron core can be made of stacked cold-rolled silicon steel sheets with high magnetic permeability, while the windings are made of wires with excellent conductivity (such as copper wires or aluminum wires). The two together constitute the core of electromagnetic energy conversion.

[0035] Insulating oil, as an important insulating and cooling medium in oil-immersed transformers, possesses excellent electrical insulation properties, thermal conductivity, and chemical stability. During normal operation of an oil-immersed transformer, the insulating oil not only isolates live parts but also transfers the heat generated by the transformer body to the tank walls through its circulation, which is then dissipated to the external environment by the heat dissipation device. This effectively prevents the transformer body from experiencing performance degradation or malfunctions due to overheating.

[0036] In this embodiment, a gas chamber is disposed above the insulating oil, and a temperature sensor and a pressure sensor are disposed within the gas chamber to monitor changes in absolute temperature and gas pressure in real time. There are no specific limitations on the type and location of the temperature and pressure sensors, as long as they can accurately measure the absolute temperature and gas pressure inside the gas chamber. For example, high-precision digital temperature and pressure sensors can be used and disposed on the top or side wall of the gas chamber, ensuring they are above the insulating oil level and do not affect the overall structural safety of the oil-immersed transformer.

[0037] As described above, the sealing performance of the oil tank is crucial for the safe operation of oil-immersed transformers. If the tank is poorly sealed, external moisture and oxygen may penetrate the insulating oil, leading to a decrease in its dielectric strength, and even causing internal discharge or breakdown accidents, ultimately resulting in the risk of combustion and explosion. Therefore, in this embodiment, it is necessary to implement qualified sealing measures for the oil tank in advance to ensure that the tank remains in a sealed environment at all times. No specific restrictions are placed on the type of sealing measures used here; those skilled in the art can select appropriate sealing measures based on actual needs.

[0038] In this embodiment, after the sealing measures for the oil tank are completed, it is assumed that the oil tank is in a sealed environment, and the oil-immersed transformer is put into use. After the oil-immersed transformer is put into operation, the absolute temperature and measured pressure inside the gas chamber are collected in real time through temperature and pressure sensors.

[0039] Optionally, in one embodiment, when the fuel tank is in a sealed environment, collecting the absolute temperature and measured pressure of the gas chamber includes: When an O-ring is installed in the annular groove of the flange of the oil tank, the absolute temperature and measured pressure of the gas chamber are collected.

[0040] In the embodiments of the present application, by arranging an O-ring seal in the annular groove of the flange of the fuel tank and assembling it with the flange end cover, the overall sealing reliability of the fuel tank can be effectively improved. The O-ring seal has good elasticity and resilience, can form a uniform sealing pressure between the flange connection surfaces, prevent the leakage of insulating oil and the intrusion of external moisture and oxygen. In addition, the installation of the O-ring seal is simple and the maintenance cost is low, and it can maintain stable sealing performance during the long-term operation of the oil-immersed transformer. By reasonably selecting the material and size of the O-ring seal, its aging resistance and corrosion resistance can be further enhanced, thereby ensuring the durability and safety of the fuel tank sealing system.

[0041] Correspondingly, in the embodiments of the present application, when an O-ring seal is assembled in the annular groove of the flange of the fuel tank, assuming that the fuel tank is in a sealed environment, and based on the absolute temperature and the measured pressure collected by the temperature sensor and the pressure sensor.

[0042] Optionally, in one embodiment, before collecting the absolute temperature and the measured pressure of the gas chamber, it further includes: Exhaust the gas chamber and inject a non-oxidizing gas into the gas chamber.

[0043] In the embodiments of the present application, the gas chamber is also evacuated to remove the air and other volatile impurities in the gas chamber, ensuring the purity of the environment in the gas chamber. In addition, there is no special limitation on the type of non-oxidizing gas injected into the gas chamber, and it can be selected according to actual needs. For example, nitrogen can be injected into the gas chamber.

[0044] As above, by injecting a non-oxidizing gas into the gas chamber, the oxygen content inside the gas chamber can be further reduced, thereby reducing the possibility of oxidation of the insulating oil and improving the stability and safety of the operation of the oil-immersed transformer.

[0045] In S120, according to the absolute temperature and the operation time of the oil-immersed transformer, the theoretical pressure is determined.

[0046] It should be noted that in the embodiments of the present application, a theoretical pressure model is established in advance, and this theoretical pressure model is used to describe the theoretical relationship between the internal pressure of the gas chamber in the fuel tank and the change of the absolute temperature inside the gas chamber and the operation time under a sealed environment.

[0047] In the embodiments of the present application, in addition to collecting the absolute temperature and the measured pressure of the gas chamber, the operation time of the oil-immersed transformer is also obtained, and this operation time is used to describe the cumulative operation duration of the oil-immersed transformer from the start of operation to the current moment.

[0048] As shown above, after collecting the absolute temperature and measured pressure of the gas chamber and obtaining the commissioning time of the oil-immersed transformer, the absolute temperature and commissioning time are substituted into the theoretical pressure model to calculate the theoretical pressure of the gas chamber at the current moment. This theoretical pressure can be understood as: the theoretical value that the internal pressure of the gas chamber should maintain under the assumption that the oil tank is always in a sealed environment and the oil-immersed transformer is operating normally.

[0049] In this embodiment of the application, the theoretical pressure model can be expressed as: ; in, This represents the theoretical pressure, and K represents a constant. This indicates the normal gas escape rate of an oil-immersed transformer. This indicates the commissioning time of the oil-immersed transformer. This indicates the amount of gas injected into the gas chamber. This indicates the absolute temperature inside the air chamber.

[0050] The value of K can be calibrated according to the specific tank structure and gas chamber parameters. For example, when an oil-immersed transformer is first put into operation, the gas chamber is filled with nitrogen. At this time, the initial absolute temperature and initial pressure in the gas chamber are collected. Combining these initial absolute temperature and initial pressure, the specific value of K can be deduced. ,in, Indicates the initial pressure. This represents the initial absolute temperature.

[0051] Optionally, in one embodiment, before determining the theoretical pressure of the gas chamber based on the absolute temperature and the commissioning time of the oil-immersed transformer, the method further includes: Compare the absolute temperature with the normal temperature range; If the absolute temperature is within the normal temperature range, then the theoretical pressure is determined based on the absolute temperature and the commissioning time of the oil-immersed transformer. If the absolute temperature is outside the normal temperature range, a temperature alarm message will be output.

[0052] The normal temperature range refers to the reasonable range of absolute temperature in the gas chamber of an oil-immersed transformer under normal operating conditions. This range can be set according to the design parameters and operating characteristics of the oil-immersed transformer. If the absolute temperature is detected to be outside this range, it indicates that there may be an abnormal operating condition.

[0053] In this embodiment, after acquiring the absolute temperature of the gas chamber, the absolute temperature is not directly used for calculating the theoretical pressure. Instead, it is first compared with a preset normal temperature range to determine whether the current operating state is abnormal. If the absolute temperature is within the normal range, the oil-immersed transformer is considered to be operating normally, and the theoretical pressure calculation can continue. If the absolute temperature is outside the normal range, it indicates that the current operating state may be abnormal, such as a cooling system malfunction or overload operation. In this case, a temperature alarm message is output to prompt maintenance personnel to check and handle the situation in a timely manner, thereby avoiding potential safety hazards.

[0054] Furthermore, it should be noted that the specific content of the temperature alarm message in this application embodiment is not limited, and may include, but is not limited to, the type and degree of temperature abnormality, as well as the suggested handling measures, so that maintenance personnel can quickly understand the fault situation and take corresponding measures.

[0055] By setting a normal temperature range judgment mechanism, not only can the accuracy of theoretical pressure calculation be improved, but the reliability of monitoring the operating status of oil-immersed transformers can also be effectively enhanced, further ensuring the stable operation and service life of oil-immersed transformers.

[0056] In S130, fault diagnosis is performed based on measured pressure and theoretical pressure to determine the type of operational fault in the oil-immersed transformer, and corresponding preventive measures are implemented.

[0057] As mentioned above, the theoretical pressure calculated using the theoretical pressure model represents the theoretical pressure that an oil-immersed transformer should maintain inside the gas chamber under normal operating conditions, with the oil tank in a sealed environment. Therefore, by comparing the measured pressure with the theoretical pressure, fault diagnosis of the oil-immersed transformer can be achieved, and the type of operational fault can be determined.

[0058] Optionally, in one embodiment, fault diagnosis is performed based on measured pressure and theoretical pressure to determine the type of operational fault in the oil-immersed transformer, and preventive measures corresponding to the type of operational fault are implemented, including: Determine the normal pressure range based on theoretical pressure; If the measured pressure is less than the normal pressure range, the fault type of the oil-immersed transformer is determined to be a sealing fault, and a sealing inspection prompt message is output so that maintenance personnel can inspect the sealing of the oil tank. If the measured pressure is greater than the normal pressure range, the operating fault type of the oil-immersed transformer is determined to be a gas production rate fault. A gas production rate fault troubleshooting prompt message is output so that maintenance personnel can further analyze the insulating oil.

[0059] In this embodiment of the application, when performing fault diagnosis, a suitable normal pressure range is first determined based on the calculated theoretical pressure. This normal pressure range can be understood as a pressure interval that includes the theoretical pressure.

[0060] After determining the normal pressure range corresponding to the theoretical pressure, the measured pressure is compared with this normal pressure range. If the measured pressure is within the normal pressure range, the oil-immersed transformer is considered to be operating normally and there is no operational fault. If the measured pressure is less than the lower limit of the normal pressure range, the oil-immersed transformer is considered to have an operational fault, and the fault type is seal failure. In this case, a seal inspection prompt message is output, prompting maintenance personnel to inspect the oil tank's sealing performance. For example, in the case of an O-ring sealing structure, maintenance personnel can check whether the O-ring is aged or deformed and replace it in time. If the measured pressure is greater than the upper limit of the normal pressure range, the oil-immersed transformer is considered to have an operational fault, and the fault type is gas production rate fault. In this case, a gas production rate fault inspection message is output, prompting maintenance personnel to further analyze the insulating oil. Therefore, by comparing the measured pressure with the theoretical pressure within the normal pressure range, it is possible to accurately determine whether there is a sealing fault or gas production rate fault in the oil-immersed transformer, and trigger corresponding maintenance prompts. This provides effective technical support and decision-making basis for maintenance personnel, enabling them to carry out targeted maintenance on the oil-immersed transformer in a timely manner, thereby effectively avoiding the risk of equipment failure caused by poor sealing or abnormal insulating oil.

[0061] It should be noted that the embodiments of this application do not limit the specific form of the above-mentioned sealing maintenance prompts and gas production rate fault maintenance prompts. These can be audible and visual alarms, screen display prompts, remote communication alarm signal transmission, etc. In practical applications, appropriate prompting methods can be selected according to the operating environment and maintenance management needs of the oil-immersed transformer to ensure that maintenance personnel can receive maintenance prompts in a timely manner and take corresponding preventive measures quickly, ensuring the safe and stable operation of the oil-immersed transformer. For example, in outdoor substations, maintenance prompts can be sent to the maintenance center via remote communication, so that on-duty maintenance personnel can grasp the fault status of the oil-immersed transformer as soon as possible, achieving all-weather, high-precision monitoring of the oil-immersed transformer's status and providing strong support for its normal operation.

[0062] Optionally, in one embodiment, determining the normal pressure range based on the theoretical pressure includes: The theoretical pressure is corrected according to the preset correction coefficient to obtain the lower limit and upper limit of the theoretical pressure. The normal pressure range is determined based on the theoretical lower pressure limit and the theoretical upper pressure limit.

[0063] This embodiment of the application introduces a preset correction coefficient to dynamically adjust the theoretical pressure, enabling more precise adaptation to the impact of different operating conditions and environmental factors, thereby further improving the accuracy of judging the operating status of oil-immersed transformers. This preset correction coefficient can be dynamically optimized and adjusted according to actual operating conditions such as the geographical location of the oil-immersed transformer, the range of ambient temperature changes, and load fluctuations, thus achieving a refined setting of the normal pressure range. For example, during high-temperature seasons or under high-load operating conditions, the correction coefficient can be appropriately increased to widen the normal pressure range and avoid false alarms caused by environmental factors; while under low-temperature or light-load conditions, the correction coefficient can be decreased to improve monitoring sensitivity and ensure timely identification of abnormal states. Through dynamic correction of the theoretical pressure, not only is the adaptability and robustness of the judgment logic enhanced, but the overall intelligence level and reliability of the operation and maintenance of oil-immersed transformers are also improved.

[0064] For example, the theoretical pressure is corrected according to a preset correction coefficient to obtain the lower limit and upper limit of the theoretical pressure, which can be expressed as follows: P_min = P_theoretical × (1 - kr); P_max = P_theoretical × (1 + kr); Where P_theoretical is the theoretical pressure value, kr is the preset correction coefficient, P_min is the lower limit of the theoretical pressure, and P_max is the upper limit of the theoretical pressure. Correspondingly, the normal pressure range can be expressed as [P_min, P_max].

[0065] As can be seen from the above, the fault diagnosis and prevention scheme for oil-immersed transformers provided in this application collects the absolute temperature and measured pressure of the gas chamber when the oil tank is in a sealed environment; determines the theoretical pressure based on the absolute temperature and the commissioning time of the oil-immersed transformer; performs fault diagnosis based on the measured pressure and theoretical pressure to determine the type of operational fault of the oil-immersed transformer, and implements the corresponding preventive measures. This scheme does not rely on complex external equipment; it can achieve real-time assessment of the temperature and pressure status of the gas chamber inside the oil tank using only built-in sensors, thereby enabling low-cost online fault diagnosis. Once a fault is detected, an alarm mechanism is triggered in a timely manner to remind maintenance personnel to take preventive measures, effectively preventing the entire transformer from burning out due to the damage of a single sealing ring; at the same time, the injection of non-oxidizing gas into the gas chamber can completely prevent the risk of combustion and explosion of the oil-immersed transformer.

[0066] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0067] 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 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 this application, and should all be included within the protection scope of this application.

Claims

1. A method for diagnosing and preventing operational faults in an oil-immersed transformer, the oil-immersed transformer comprising a transformer body and an oil tank, wherein the oil tank contains insulating oil, the transformer body is immersed in the insulating oil, and an air chamber is disposed above the insulating oil, characterized in that... The methods for diagnosing and preventing operational faults in oil-immersed transformers include: When the oil tank is in a sealed environment, the absolute temperature and measured pressure of the gas chamber are collected; The theoretical pressure is determined based on the absolute temperature and the commissioning time of the oil-immersed transformer. Based on the measured pressure and the theoretical pressure, fault diagnosis is performed to determine the type of operational fault of the oil-immersed transformer, and preventive measures corresponding to the type of operational fault are implemented.

2. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to claim 1, characterized in that, When the oil tank is in a sealed environment, the absolute temperature and measured pressure of the gas chamber are collected, including: When an O-ring is installed in the annular groove of the flange of the oil tank, the absolute temperature and measured pressure of the gas chamber are collected.

3. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to claim 1, characterized in that, The theoretical pressure is determined according to the following formula: ； in, This represents the theoretical pressure, where K represents a constant. This indicates the normal gas escape rate of the oil-immersed transformer. This indicates the commissioning time of the oil-immersed transformer. This indicates the amount of gas injected into the gas chamber. This indicates the absolute temperature.

4. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to claim 1, characterized in that, The step of fault diagnosis based on the measured pressure and the theoretical pressure to determine the type of operational fault of the oil-immersed transformer, and the execution of corresponding preventive measures for the type of operational fault, includes: Based on the theoretical pressure, determine the normal pressure range; If the measured pressure is less than the normal pressure range, the operating fault type of the oil-immersed transformer is determined to be a sealing fault, and a sealing inspection prompt message is output so that maintenance personnel can inspect the sealing of the oil tank. If the measured pressure is greater than the normal pressure range, the operating fault type of the oil-immersed transformer is determined to be a gas production rate fault, and a gas production rate fault maintenance prompt message is output so that maintenance personnel can further analyze the insulating oil.

5. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to claim 4, characterized in that, Determining the normal pressure range based on the theoretical pressure includes: The theoretical pressure is corrected according to a preset correction coefficient to obtain the lower limit and upper limit of the theoretical pressure. The normal pressure range is determined based on the theoretical lower pressure limit and the theoretical upper pressure limit.

6. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to any one of claims 1-5, characterized in that, Before collecting the absolute temperature and measured pressure of the gas chamber, the method further includes: The gas chamber is emptied and a non-oxidizing gas is injected into it.

7. The method for diagnosing and preventing operational faults in an oil-immersed transformer according to any one of claims 1-5, characterized in that, Before determining the theoretical pressure of the gas chamber based on the absolute temperature and the commissioning time of the oil-immersed transformer, the method further includes: Compare the absolute temperature with the normal temperature range; If the absolute temperature is within the normal temperature range, then the theoretical pressure is determined based on the absolute temperature and the commissioning time of the oil-immersed transformer. If the absolute temperature is outside the normal temperature range, a temperature alarm message will be output.

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