Transformer operation state monitoring and fault early warning method based on state index calculation

Abstract

The invention discloses a transformer operation state monitoring and fault early warning method based on state index calculation, relates to the technical field of transformer operation state monitoring, and is used for solving the problem that the accuracy of potential fault identification is reduced. Calculating an operation stress coefficient by combining the temperature rise trend and the vibration frequency, detecting the conductivity of insulating oil in an oil circulation pipeline, generating a state index by combining the conductivity and the operation stress coefficient, classifying the operation state of the transformer according to the state index, and inputting multiple groups of different cooling powers and setting monitoring time when the state is an alarm; according to the method, the corresponding radiator outlet air temperature is collected, the power variation and the outlet air temperature difference variation are calculated after the cooling power is sequenced, the heat dissipation characteristics are comprehensively evaluated, and whether a fault warning signal is generated or not is judged, so that early warning of potential faults of the transformer is achieved, and the operation safety and reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of transformer operating status monitoring technology, and more specifically, to a method for transformer operating status monitoring and fault early warning based on state index calculation. Background Technology

[0002] As a key piece of equipment in the power system, the safety and stability of transformer operation directly affect the reliable power supply capacity of the entire power grid. In the existing technology, the monitoring of transformer operating status mainly focuses on the detection of single parameters, such as collecting winding temperature to assess temperature rise, detecting mechanical condition through vibration sensors, or judging insulation condition by monitoring the electrical properties of insulating oil (such as conductivity, dielectric loss factor, etc.).

[0003] The existing technology has the following shortcomings: Currently, existing single-parameter monitoring methods and threshold-based alarm mechanisms cannot fully reflect the comprehensive operating status of transformers and lack the ability to fuse and model multi-source operating data and dynamically evaluate them, resulting in reduced accuracy in identifying potential faults and increased lag in early warning response. Therefore, a transformer operating status monitoring and fault early warning method based on state index calculation is proposed.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for monitoring transformer operating status and providing early warning of faults based on state index calculation. By employing a fusion modeling approach that integrates temperature rise trend, vibration frequency, and insulating oil conductivity, a state index is generated, and a dynamic evaluation mechanism combining cooling power and heat dissipation characteristics is combined to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for monitoring the operating status and providing early warning of faults of transformers based on state index calculation, comprising the following steps: Step S1: During the operation of the transformer, the winding temperature of the transformer is collected and the temperature rise trend is calculated. The vibration state of the transformer is monitored and the vibration frequency is calculated based on the vibration state. Step S2: Calculate the operating stress coefficient by combining the temperature rise trend with the vibration frequency, detect the conductivity of the insulating oil in the oil circulation pipeline, generate a state index by combining the conductivity of the insulating oil and the operating stress coefficient, and classify the operating state of the transformer according to the state index. Step S3: When the operating status is alarm status, select multiple different cooling power inputs to the transformer, set the monitoring time, and collect the radiator outlet temperature under each cooling power during the monitoring time. Step S4: Sort the cooling power, calculate the power change of adjacent cooling power and the change of radiator outlet temperature difference, evaluate the heat dissipation characteristics by combining the power change and the change of radiator outlet temperature difference, and use the heat dissipation characteristics to determine whether to generate a fault alarm signal.

[0007] In a preferred embodiment, in step S1, during the operation of the transformer, a preset acquisition period is set, and the winding temperature of the transformer is obtained through an infrared temperature sensor. The difference between the winding temperatures of the transformer at each adjacent acquisition time is calculated to obtain the change in winding temperature of the transformer. The average value of the temperature rise change of the windings of each transformer within the preset collection period is calculated as the temperature rise trend.

[0008] In a preferred embodiment, in step S1, the vibration state includes peak vibration acceleration and vibration period interval; The vibration acceleration signal of the transformer is acquired by an accelerometer within a preset acquisition period. After filtering the vibration acceleration signal, the peak value in the vibration acceleration signal is taken as the peak vibration acceleration, and the timestamp corresponding to the peak vibration acceleration is recorded. The adjacent peak timestamps are obtained by subtracting the timestamps of adjacent peak accelerations in the same direction. If the adjacent peak timestamps are greater than the preset time interval threshold, the adjacent peak timestamps are used as the vibration period interval; otherwise, the adjacent peak timestamps are discarded. The reciprocal of the vibration period interval is taken as the vibration frequency.

[0009] In a preferred embodiment, in step S2, the temperature rise trend and vibration frequency are normalized using the Max-Min normalization method. The operating stress coefficient is calculated by combining the temperature rise trend and the normalized value of the vibration frequency. An AC excitation voltage is generated on the outer wall of the oil circulation pipeline by an external capacitor coupling clamp, and the induced current is collected. The absolute value of the ratio of induced current to AC excitation voltage is used as the amplitude admittance; The ratio of amplitude admittance to preset calibration coefficient is used as the conductivity of insulating oil in the oil circulation pipeline.

[0010] In a preferred embodiment, in step S2, the normalized value of the conductivity of the insulating oil is combined with the operating stress coefficient to calculate the state index; The state index is compared with a preset state index threshold for determination. If the state index is less than the preset state index threshold, the transformer is in normal operating condition. Conversely, the transformer will be in an alarm state.

[0011] In a preferred embodiment, in step S3, when the operating state is an alarm state, the cooling response test procedure is executed: The control unit selects multiple different cooling power inputs from the cooling power meter; Set a monitoring time, and within the monitoring time, collect the radiator outlet air temperature under multiple different cooling powers using a digital temperature sensor.

[0012] In a preferred embodiment, in step S4, multiple sets of different cooling powers are sorted in ascending order according to their numerical values ​​and integrated into a cooling power sequence. The absolute value of the difference between adjacent cooling power in the cooling power sequence is taken as the power change of adjacent cooling power; The radiator outlet temperatures are integrated into a radiator outlet temperature sequence based on the order of cooling power in the cooling power sequence and the corresponding radiator outlet temperature.

[0013] In a preferred embodiment, in step S4, the absolute value of the temperature difference between adjacent radiators in the radiator outlet temperature sequence is taken as the change in radiator outlet temperature difference. Standardize the power variation of adjacent cooling power units and the temperature difference variation of radiator outlet air. The heat dissipation characteristics are calculated by combining the power change of the cooling power after comprehensive standardization and the change of the radiator outlet air temperature difference.

[0014] In a preferred embodiment, in step S4, the heat dissipation characteristics are compared with a preset heat dissipation characteristic threshold for determination: If the heat dissipation characteristic is less than or equal to the preset heat dissipation characteristic threshold, a fault alarm signal will be generated. If the heat dissipation characteristics are greater than the preset heat dissipation characteristic threshold, no fault alarm signal will be generated.

[0015] The technical effects and advantages of this invention are as follows: This invention collects winding temperature and calculates temperature rise trends during transformer operation, while simultaneously monitoring vibration status. Vibration frequency is calculated based on vibration status, and the operating stress coefficient is calculated by combining temperature rise trends and vibration frequency. The conductivity of insulating oil in the oil circulation pipeline is detected, and a state index is generated by combining the insulating oil conductivity and operating stress coefficient. The transformer operating status is then classified according to the state index. When the operating status is in an alarm state, multiple sets of different cooling power are input to the transformer, and a monitoring time is set. During the monitoring time, the radiator outlet air temperature under each cooling power is collected, the cooling power is sorted, and the power change of adjacent cooling power and the change in radiator outlet air temperature difference are calculated. The heat dissipation characteristics are comprehensively evaluated, and the heat dissipation characteristics are used to determine whether a fault alarm signal should be generated. This timely detection of heat dissipation anomalies and generation of alarm signals enables early warning of potential transformer faults, improving operational safety and reliability. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the implementation of the transformer operation status monitoring and fault early warning method based on state index calculation according to the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the steps of the transformer operation status monitoring and fault early warning method based on state index calculation according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0019] This invention collects winding temperature and calculates temperature rise trend during transformer operation, while simultaneously monitoring vibration status. Vibration frequency is calculated based on vibration status, and the operating stress coefficient is calculated by combining temperature rise trend and vibration frequency. The conductivity of insulating oil in the oil circulation pipeline is detected, and a state index is generated by combining insulating oil conductivity and operating stress coefficient. The transformer operating status is then classified according to the state index. When the operating status is in an alarm state, multiple sets of different cooling power are input to the transformer, and a monitoring time is set. During the monitoring time, the radiator outlet air temperature under each cooling power is collected, the cooling power is sorted, and the power change of adjacent cooling power and the change of radiator outlet air temperature difference are calculated. The heat dissipation characteristics are comprehensively evaluated, and the heat dissipation characteristics are used to determine whether a fault alarm signal should be generated. This timely detection of heat dissipation anomalies and generation of alarm signals enables early warning of potential transformer faults.

[0020] Please see Figures 1 to 2A method for monitoring transformer operating status and providing early warning of faults based on state index calculation includes the following steps: Step S1: During the operation of the transformer, the winding temperature of the transformer is collected and the temperature rise trend is calculated. The vibration state of the transformer is monitored and the vibration frequency is calculated based on the vibration state. Step S2: Calculate the operating stress coefficient by combining the temperature rise trend with the vibration frequency, detect the conductivity of the insulating oil in the oil circulation pipeline, generate a state index by combining the conductivity of the insulating oil and the operating stress coefficient, and classify the operating state of the transformer according to the state index. Step S3: When the operating status is alarm status, select multiple different cooling power inputs to the transformer, set the monitoring time, and collect the radiator outlet temperature under each cooling power during the monitoring time. Step S4: Sort the cooling power, calculate the power change of adjacent cooling power and the change of radiator outlet temperature difference, evaluate the heat dissipation characteristics by combining the power change and the change of radiator outlet temperature difference, and use the heat dissipation characteristics to determine whether to generate a fault alarm signal.

[0021] The specific implementation is as follows: In step S1, during the operation of the transformer, a preset acquisition period is divided into multiple acquisition times, and the winding temperature of the transformer is obtained through an infrared temperature sensor. The difference between the winding temperatures of the transformer at each adjacent acquisition time is calculated to obtain the change in winding temperature of the transformer. The average value of the temperature rise change of the transformer windings at all acquisition times within the preset acquisition period is calculated as the temperature rise trend. It should be noted that the preset acquisition cycle is used to periodically acquire the winding temperature of the transformer. The setting of the preset acquisition cycle should take into account the frequency of change and data fluctuation of the transformer winding temperature during transformer operation to ensure that sufficient data is acquired in each cycle. The infrared temperature sensor is a non-contact temperature measurement device that receives the infrared radiation energy emitted by the surface of an object and converts it into an electrical signal. After calculation by internal circuits and algorithms, the corresponding temperature value is output to obtain the winding temperature of the transformer.

[0022] Vibration state refers to the overall manifestation of mechanical vibration characteristics of a transformer during operation, caused by electromagnetic force, thermal expansion force, or external disturbance, including peak acceleration and vibration period interval. Within a preset acquisition period, the vibration acceleration signal of the transformer is acquired through an accelerometer. After filtering the vibration acceleration signal, the peak value in the vibration acceleration signal is taken as the peak vibration acceleration, and the timestamp corresponding to the peak vibration acceleration is recorded. The adjacent peak timestamps are obtained by subtracting the timestamps of adjacent peak accelerations in the same direction. If the adjacent peak timestamps are greater than the preset time interval threshold, the adjacent peak timestamps are used as the vibration period interval; otherwise, the adjacent peak timestamps are discarded. The reciprocal of the vibration period interval is taken as the vibration frequency.

[0023] It should be explained that an accelerometer is a sensor that can measure the magnitude and direction of an object's acceleration. It is used to detect the motion and vibration of an object and can acquire the vibration acceleration signal of a transformer. Adjacent co-directional peak accelerations refer to the maximum acceleration values ​​that occur in two adjacent vibration cycles and have the same direction. They are used to obtain the vibration cycle interval corresponding to adjacent co-directional peak accelerations. The preset time interval threshold is a critical time interval used to distinguish and filter vibration cycle intervals. It is set according to the minimum expected vibration cycle of the transformer at the rated power frequency. For example, the magnetostriction of the transformer core and the electromagnetic force of the windings at a power frequency of 50Hz generate a fundamental frequency vibration of 100Hz, with a period of 10ms. The time interval threshold should be set to a value less than the fundamental frequency period. The preset time interval threshold can be 6ms to 8ms. The specific setting should be done by professionals and will not be elaborated here.

[0024] In step S2, the temperature rise trend and vibration frequency are normalized using the Max-Min normalization method. The calculation formula is as follows: , ,in, and It is the temperature rise trend and the vibration frequency. and These are the minimum and maximum values ​​of the temperature rise trend. and These are the minimum and maximum values ​​of the vibration frequency. and These are the normalized values ​​of the temperature rise trend and the vibration frequency, respectively. The operating stress coefficient is calculated by combining the temperature rise trend and the normalized value of the vibration frequency. The calculation formula is as follows: ,in, This is the value after normalizing the temperature rise trend. It is the value after normalizing the vibration frequency. It is the operating stress coefficient; It should be noted that the greater the temperature rise trend and the higher the vibration frequency, the greater the transformer operating load and the greater the operating stress coefficient; conversely, the smaller the temperature rise trend and the lower the vibration frequency, the smaller the transformer operating load and the smaller the operating stress coefficient. An AC excitation voltage is generated on the outer wall of the oil circulation pipeline by an external capacitor coupling clamp, and the induced current is collected. The absolute value of the ratio of the collected induced current to the generated AC excitation voltage is used as the amplitude admittance. The ratio of amplitude admittance to preset calibration coefficient is used as the conductivity of insulating oil in the oil circulation pipeline; The conductivity of the insulating oil is normalized using the following formula: ,in, For the first The conductivity of the insulating oil at each sampling time. This is the number of data collection moments within a preset data collection period. This is the normalized value of the conductivity of the insulating oil; It should be noted that the external capacitive coupling clamp is a device used for non-contact signal acquisition and transmission. Utilizing the capacitive coupling effect, it achieves the induction and transmission of electrical signals inside the conductor by clamping electrode plates to the outside of the conductor without directly stripping the conductor's insulation layer. It is used to generate AC excitation voltage on the outer wall of the oil circulation pipeline and to collect the induced current. The amplitude admittance is the magnitude of the admittance in an AC circuit, used to describe the circuit's conductivity to AC current. The preset calibration coefficient is a proportional coefficient used to convert the measured amplitude admittance into the actual conductivity of the insulating oil. The preset calibration coefficient is obtained by sampling and calculating insulating oil with known conductivity under the same experimental environment and acquisition equipment.

[0025] The normalized conductivity of the insulating oil is combined with the operating stress coefficient to calculate the state index. The calculation formula is as follows: ,in, This is the normalized value of the conductivity of the insulating oil. The operating stress coefficient, and To preset the weighting coefficients, It is a state index; It should be noted that the higher the conductivity of the insulating oil, the higher the operating stress coefficient, which leads to a decrease in the performance of the insulating oil and a higher operating stress on the transformer, resulting in a higher state index. Conversely, the lower the conductivity of the insulating oil, the lower the operating stress coefficient, which indicates good performance of the insulating oil and stable operation of the transformer, resulting in a lower state index. The preset weighting coefficient is used to adjust the influence of the normalized value of the insulating oil conductivity and the operating stress coefficient on the state index. It is set based on the contribution of the insulating oil conductivity and operating stress coefficient to the state index in historical monitoring data. For example, multiple sets of insulating oil conductivity and operating stress coefficients are obtained from historical monitoring data, and the corresponding state indices are labeled. The Pearson correlation coefficient is used to calculate the linear correlation between the insulating oil conductivity, operating stress coefficient, and state index, and the preset weighting coefficient is then used.

[0026] The state index is compared with a preset state index threshold for determination. If the state index is less than the preset state index threshold, the transformer is in normal operating condition. If the state index is greater than or equal to the preset state index threshold, the transformer's operating state is an alarm state.

[0027] It should be explained that the preset state index threshold is an important parameter for determining whether a transformer is in an alarm state. The preset state index threshold can be determined based on the statistical characteristics of historical state index data during normal operation. For example, when the transformer is in normal operation, state indices are continuously collected over multiple collection periods to form a historical state index sequence. The historical state index sequence is analyzed to obtain the average and standard deviation of the state indices. The preset state index threshold is then calculated based on the average and several multiples of the standard deviation. A normal state indicates that under current operating conditions, the transformer's insulation performance, mechanical structure, and heat dissipation capacity are all at a healthy level, requiring no immediate intervention. An alarm state indicates that under current operating conditions, the transformer may have potential risks such as overheating, overload, abnormal vibration, or decreased insulation performance, prompting timely inspection, adjustment of cooling measures, or maintenance to prevent further deterioration and equipment failure.

[0028] In step S3, when the running status is in alarm status, the cooling response test procedure is executed, and the specific procedure is as follows: The control unit selects multiple different cooling power inputs from the cooling power meter to input to the transformer; Set a monitoring time, and within the monitoring time, collect the radiator outlet air temperature under multiple different cooling powers using a digital temperature sensor.

[0029] It needs to be explained that the control unit is a functional unit used for centralized management, decision-making, and execution of instructions for equipment or systems, and is used to select multiple different cooling power levels; the cooling power meter is a reference table or database used to store and manage preset cooling power parameters, which is usually read by the control unit to guide the selection of power input for transformers or equipment cooling systems; the monitoring time refers to a preset time period used to collect and record specific parameter data during operation or testing, for example, by monitoring the thermal inertia time and cooling response time of transformers and heat dissipation systems, the monitoring time is set to be greater than or equal to the thermal inertia time and cooling response time; the digital temperature sensor is a temperature measuring device that can directly output digital signals, used to collect the radiator outlet air temperature under multiple different cooling power levels; the radiator outlet air temperature is the temperature at which the radiator outlet air temperature tends to stabilize and no longer change at the time of collection.

[0030] In step S4, multiple sets of different cooling powers are sorted in ascending order according to their numerical values ​​and integrated into a cooling power sequence; The absolute value of the difference between adjacent cooling power in the cooling power sequence is taken as the power change of adjacent cooling power; The radiator outlet temperature is integrated into a radiator outlet temperature sequence based on the order of cooling power in the cooling power sequence and the corresponding radiator outlet temperature. The absolute value of the temperature difference between adjacent radiators in the radiator outlet temperature sequence is taken as the change in radiator outlet temperature difference. Standardize the power variation of adjacent cooling power units and the temperature difference variation of radiator outlet air. The heat dissipation characteristics are calculated by combining the power change of the standardized cooling power and the change of the radiator outlet air temperature difference. The calculation formula is as follows: ,in, This represents the number of power changes between adjacent cooling power units. For the first The change in outlet air temperature difference of a radiator after standardization treatment. For the first The change in cooling power after standardization. Features related to heat dissipation; It should be noted that the greater the change in cooling power and the smaller the change in radiator outlet temperature difference, the weaker the cooling system's response to power input, the insufficient or abnormal heat dissipation capacity, and the smaller the heat dissipation characteristics. Conversely, the smaller the change in cooling power and the greater the change in radiator outlet temperature difference, the more significant the radiator's response to power adjustment, the better the heat dissipation capacity, and the greater the heat dissipation characteristics.

[0031] The heat dissipation characteristics are compared with a preset heat dissipation characteristic threshold for judgment. If the heat dissipation characteristic is less than or equal to the preset heat dissipation characteristic threshold, a fault alarm signal will be generated. If the heat dissipation characteristics are greater than the preset heat dissipation characteristic threshold, no fault alarm signal will be generated.

[0032] It should be explained that the standardization methods include, but are not limited to, standard linear transformation based on interval scaling, Z-Score standardization based on statistics, or normalization based on nonlinear mapping functions. The application methods of standardization will not be elaborated here. The preset heat dissipation characteristic threshold is an important parameter for determining whether to generate a fault alarm signal. By analyzing the historical heat dissipation characteristics and corresponding heat dissipation states, the critical value between normal and abnormal states is analyzed, and the critical value between normal and abnormal states is selected as the preset heat dissipation characteristic threshold. The fault alarm signal refers to the prompt or alarm information actively issued when abnormal equipment operating parameters or potential faults are detected, which is used to remind maintenance personnel or automatic control systems to take corresponding measures.

[0033] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0034] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0035] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0036] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0037] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes 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.

[0038] 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.

[0039] Those skilled in the art will 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.

[0040] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, 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.

[0041] 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 according to actual needs.

[0042] In addition, the functional units in the various embodiments of this application 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.

[0043] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0044] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the above specification.

Claims

1. A method for monitoring transformer operating status and providing early warning of faults based on state index calculation, characterized in that: Includes the following steps: Step S1: During the operation of the transformer, the winding temperature of the transformer is collected and the temperature rise trend is calculated. The vibration state of the transformer is monitored and the vibration frequency is calculated based on the vibration state. Step S2: Calculate the operating stress coefficient by combining the temperature rise trend with the vibration frequency, detect the conductivity of the insulating oil in the oil circulation pipeline, generate a state index by combining the conductivity of the insulating oil and the operating stress coefficient, and classify the operating state of the transformer according to the state index. Step S3: When the operating status is alarm status, select multiple different cooling power inputs to the transformer, set the monitoring time, and collect the radiator outlet temperature under each cooling power during the monitoring time. Step S4: Sort the cooling power, calculate the power change of adjacent cooling power and the change of radiator outlet temperature difference, evaluate the heat dissipation characteristics by combining the power change and the change of radiator outlet temperature difference, and use the heat dissipation characteristics to determine whether to generate a fault alarm signal.

2. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 1, characterized in that: In step S1, during the operation of the transformer, a preset acquisition period is set, and the winding temperature of the transformer is obtained through an infrared temperature sensor. The difference between the winding temperatures of the transformer at each adjacent acquisition time is calculated to obtain the change in winding temperature of the transformer. The average value of the temperature rise change of the windings of each transformer within the preset collection period is calculated as the temperature rise trend.

3. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 1, characterized in that: In step S1, the vibration state includes peak vibration acceleration and vibration period interval; The vibration acceleration signal of the transformer is acquired by an accelerometer within a preset acquisition period. After filtering the vibration acceleration signal, the peak value in the vibration acceleration signal is taken as the peak vibration acceleration, and the timestamp corresponding to the peak vibration acceleration is recorded. The adjacent peak timestamps are obtained by subtracting the timestamps of adjacent peak accelerations in the same direction. If the adjacent peak timestamps are greater than the preset time interval threshold, the adjacent peak timestamps are used as the vibration period interval; otherwise, the adjacent peak timestamps are discarded. The reciprocal of the vibration period interval is taken as the vibration frequency.

4. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 1, characterized in that: In step S2, the temperature rise trend and vibration frequency are normalized using the Max-Min normalization method; The operating stress coefficient is calculated by combining the temperature rise trend and the normalized value of the vibration frequency. An AC excitation voltage is generated on the outer wall of the oil circulation pipeline by an external capacitor coupling clamp, and the induced current is collected. The absolute value of the ratio of induced current to AC excitation voltage is used as the amplitude admittance; The ratio of amplitude admittance to preset calibration coefficient is used as the conductivity of insulating oil in the oil circulation pipeline.

5. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 4, characterized in that: In step S2, the normalized value of the conductivity of the insulating oil is combined with the operating stress coefficient to calculate the state index; The state index is compared with a preset state index threshold for determination. If the state index is less than the preset state index threshold, the transformer is in normal operating condition. Conversely, the transformer will be in an alarm state.

6. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 1, characterized in that: In step S3, when the running status is in alarm status, the cooling response test procedure is executed: The control unit selects multiple different cooling power inputs from the cooling power meter to input to the transformer; Set a monitoring time, and within the monitoring time, collect the radiator outlet air temperature under multiple different cooling powers using a digital temperature sensor.

7. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 1, characterized in that: In step S4, multiple sets of different cooling power are sorted in ascending order according to their numerical values ​​and integrated into a cooling power sequence; The absolute value of the difference between adjacent cooling power in the cooling power sequence is taken as the power change of adjacent cooling power; The radiator outlet temperatures are integrated into a radiator outlet temperature sequence based on the order of cooling power in the cooling power sequence and the corresponding radiator outlet temperature.

8. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 7, characterized in that: In step S4, the absolute value of the temperature difference between adjacent radiators in the radiator outlet temperature sequence is taken as the change in radiator outlet temperature difference. Standardize the power variation of adjacent cooling power units and the temperature difference variation of radiator outlet air. The heat dissipation characteristics are calculated by combining the power change of the cooling power after comprehensive standardization and the change of the radiator outlet air temperature difference.

9. The method for monitoring transformer operating status and providing early warning of faults based on state index calculation according to claim 8, characterized in that: In step S4, the heat dissipation characteristics are compared with a preset heat dissipation characteristic threshold for determination: If the heat dissipation characteristic is less than or equal to the preset heat dissipation characteristic threshold, a fault alarm signal will be generated. If the heat dissipation characteristics are greater than the preset heat dissipation characteristic threshold, no fault alarm signal will be generated.

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