Oil-immersed transformer high-voltage winding temperature measuring device and temperature measuring method

Abstract

The application discloses a kind of oil-immersed transformer high-voltage winding temperature measuring device and temperature measuring method, including current transformer, temperature sensor and measurement and control device;The current transformer is used to measure the secondary current of the low-voltage side of transformer;The temperature sensor is used to measure the low-voltage winding temperature signal of transformer;The measurement and control device is used to collect the secondary current of low-voltage side and low-voltage winding temperature signal, according to the size of the preset winding temperature response characteristic protection logic judgment preset time period secondary current of low-voltage side and rated current preset value, according to the judgment result corresponding calculation formula is selected, and then according to the temperature of low-voltage winding, the temperature of high-voltage winding is calculated.The application has the advantages of simple structure, easy operation and the like, without installing temperature measuring device on high-voltage winding, can effectively control the oil tank volume of oil-immersed transformer, greatly reduces cost.

Description

Technical Field

[0001] This invention relates to the technical field of oil-immersed transformers, and in particular to a temperature measuring device and method for the high-voltage winding of an oil-immersed transformer. Background Technology

[0002] Oil-immersed transformers play a crucial role in voltage and current conversion and power transmission in step-up systems, and their operating conditions have a significant impact on the safe and reliable operation of the system. Among these factors, the temperature of the windings is a critical factor affecting the transformer's lifespan and reliability.

[0003] Currently, temperature measurement of high and low voltage windings requires the installation of winding temperature measuring devices on each of the three-phase high and low voltage windings. The advantage of this approach is that the temperature of the corresponding winding can be obtained directly. However, the winding temperature measuring devices are expensive; for example, six sets of devices are needed to achieve temperature measurement of the three-phase high and low voltage windings in a three-phase transformer. Furthermore, due to the limited internal space of the oil tank in an oil-immersed transformer, installing temperature measuring devices on the high-voltage winding requires increasing the tank volume. Both of these factors increase the cost of the transformer. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a temperature measuring device for the high-voltage winding of an oil-immersed transformer. This device has the advantages of simple structure and easy operation. It eliminates the need to install a temperature measuring device on the high-voltage winding, effectively controls the volume of the oil tank of the oil-immersed transformer, and greatly reduces costs.

[0005] To obtain the temperature of the high-voltage winding of an oil-immersed transformer.

[0006] Another objective of this invention is to provide a method for measuring the temperature of the high-voltage winding of an oil-immersed transformer.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A temperature measuring device for the high-voltage winding of an oil-immersed transformer includes a current transformer, a temperature sensor, and a measurement and control device.

[0009] The current transformer is used to measure the secondary current on the low-voltage side of the transformer;

[0010] The temperature sensor is used to measure the temperature signal of the low-voltage winding of the transformer;

[0011] The measurement and control device is used to collect the low-voltage side secondary current and low-voltage winding temperature signals, and to determine the magnitude of the low-voltage side secondary current and the preset value of the rated current within a preset time period according to the preset winding temperature response characteristic protection logic. Based on the judgment result, the corresponding calculation formula is selected, and then the temperature of the high-voltage winding is calculated based on the low-voltage winding temperature.

[0012] Furthermore, the measurement and control device includes a signal acquisition module, a signal conversion module, a signal processing module, a display module, and a data transmission module. The signal acquisition module is used to acquire the low-voltage side secondary current measured by the current transformer and the low-voltage winding temperature measured by the temperature sensor. The signal conversion module is used to convert the low-voltage side secondary current and low-voltage winding temperature signals into digital signals and transmit them to the signal processing module. The signal processing module is used to store the digital signals transmitted by the signal conversion module, determine the magnitude of the low-voltage side secondary current and the preset value of the rated current within a preset time period according to the preset winding temperature response characteristic protection logic, select the corresponding calculation formula according to the determination result, and then calculate the temperature of the high-voltage winding based on the low-voltage winding temperature. The display module is used to display the calculation results. The data transmission module is used to output the calculation results.

[0013] Furthermore, the signal processing module includes a register module for storing data, a judgment module for determining the protection logic based on the winding temperature response characteristics, and a calculation module for calculating the high-voltage winding temperature.

[0014] Furthermore, the current transformer is located on the low-voltage side of the transformer.

[0015] Furthermore, the temperature sensor is located on the low-voltage side of the transformer.

[0016] Furthermore, the step of determining the magnitude of the low-voltage side secondary current and the preset value of the rated current within a preset time period based on the preset winding temperature response characteristic protection logic, selecting the corresponding calculation formula based on the determination result, and then calculating the temperature of the high-voltage winding based on the low-voltage winding temperature includes:

[0017] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period longer than the preset time period, then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H , among which, T L T represents the low-voltage winding temperature. H △T represents the temperature of the high-voltage winding, and △T represents the temperature difference between the high-voltage and low-voltage windings calculated under the full-power operation of the transformer during the temperature rise test.

[0018] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period, then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0019] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current, or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current, does not exceed the preset duration, then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0020] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset time period, then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0021] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset time period, then the high-voltage winding temperature T will continue to be calculated according to the formula used in the previous preset time period. H ;

[0022] At all times, T L ≥T H ≥T o .

[0023] Furthermore, the monitoring and control device sets the winding temperature response characteristic protection logic based on the temperature relationship between the high-voltage and low-voltage windings and the actual operating state of the transformer, specifically including:

[0024] First, calculate the temperature difference between the high-voltage and low-voltage windings:

[0025] During transformer temperature rise testing, the temperatures of the high-voltage and low-voltage windings at full power are calculated using the test currents and rated currents of the high-voltage and low-voltage windings, based on the temperature formulas for the high-voltage and low-voltage windings.

[0026]

[0027]

[0028] Among them, T o T represents the temperature of the top layer of the transformer oil tank. L T represents the low-voltage winding temperature. H I represents the high-voltage winding temperature. rL I represents the rated current of the low-voltage winding. tL I represents the low-voltage winding test current. rH I represents the rated current of the high-voltage winding. tH This represents the test current of the high-voltage winding;

[0029] Based on the temperatures of the high-voltage and low-voltage windings, the temperature difference ΔT between the high-voltage and low-voltage windings is calculated as follows:

[0030] △T=T L -T H ;

[0031] Next, determine the temperature relationship between the high-voltage and low-voltage windings:

[0032] Based on the temperature difference characteristics of the high and low voltage windings, when the transformer power is greater than or equal to 60% of the rated power, the high voltage winding temperature T H The calculation formula is:

[0033] T H =T L -△T;

[0034] When the transformer power is less than 60% of the rated power, the high-voltage winding temperature T H The calculation formula is:

[0035] T H =T L ;

[0036] Finally, the winding temperature response characteristic protection logic is set according to the actual operating conditions of the transformer:

[0037] At the high voltage winding temperature T H Based on the calculation formula, hysteresis control is used to set the protection logic for the high-voltage winding temperature response characteristics.

[0038] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period longer than the preset time period, then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H ;

[0039] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period, then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0040] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current, or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current, does not exceed the preset duration, then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0041] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset time period, then according to the calculation formula T... H =TL Calculate the high-voltage winding temperature T H ;

[0042] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset time period, then the high-voltage winding temperature T will continue to be calculated according to the formula used in the previous preset time period. H ;

[0043] At all times, T L ≥T H ≥T o .

[0044] Another objective of this invention is achieved through the following technical solution:

[0045] A method for measuring the temperature of the high-voltage winding of an oil-immersed transformer, utilizing the aforementioned oil-immersed transformer high-voltage winding temperature measuring device, includes the following steps:

[0046] S1. Connect the current transformer and temperature sensor to the low-voltage side of the transformer respectively;

[0047] S2. Connect the transformer to the power grid and operate it according to the actual working conditions;

[0048] S3. Measure the secondary current on the low-voltage side of the transformer and the temperature signal of the low-voltage winding using a current transformer and a temperature sensor, respectively.

[0049] S4. The low-voltage side secondary current and low-voltage winding temperature signals are collected by the measurement and control device. The magnitude of the low-voltage side secondary current and the rated current preset value within the preset time period is judged according to the preset winding temperature response characteristic protection logic. The corresponding calculation formula is selected according to the judgment result, and then the temperature of the high-voltage winding is calculated according to the low-voltage winding temperature.

[0050] S5. The calculated high-voltage winding temperature is displayed and transmitted through the measurement and control device.

[0051] Furthermore, step S4 includes the following steps:

[0052] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period longer than the preset time period, then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H , among which, T L T represents the low-voltage winding temperature. H △T represents the temperature of the high-voltage winding, and △T represents the temperature difference between the high-voltage and low-voltage windings calculated under the full-power operation of the transformer during the temperature rise test.

[0053] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period, then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0054] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current, or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current, does not exceed the preset duration, then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0055] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset time period, then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0056] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset time period, then the high-voltage winding temperature T will continue to be calculated according to the formula used in the previous preset time period. H ;

[0057] At all times, T L ≥T H ≥T o .

[0058] Furthermore, the preset time period is 30 minutes, and the preset duration is 20 minutes.

[0059] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0060] This invention has the advantages of simple structure and easy operation. It eliminates the need to install temperature measuring devices on the high-voltage winding, effectively controls the tank volume of the oil-immersed transformer, and greatly reduces costs. At the same time, the number of components installed on the oil-immersed transformer is small, reducing potential failure points. Attached Figure Description

[0061] Figure 1 This is a schematic diagram illustrating the working principle of the temperature measuring device and method.

[0062] Figure 2 A flowchart for setting the protection logic for the winding temperature response characteristics of the temperature measuring device and the temperature measuring method, and calculating the high-voltage winding temperature.

[0063] Figure 3 This is a hysteresis control logic diagram for the temperature measuring device and method. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0065] Example 1:

[0066] like Figure 1 As shown, this embodiment provides a temperature measuring device for the high-voltage winding of an oil-immersed transformer, including a current transformer 1, a temperature sensor (not shown in the figure), and a measurement and control device 2;

[0067] The current transformer 1 is located on the low-voltage side of the transformer 3 and is used to measure the secondary current on the low-voltage side of the transformer. The measured secondary current has a linear relationship with the apparent power of the transformer. By measuring the secondary current and combining it with the turns ratio of the current transformer, the power change of the transformer can be reflected.

[0068] The temperature sensor is located on the low-voltage side of the transformer and is used to measure the temperature signal of the low-voltage winding of the transformer, serving as a reference for measuring the temperature of the high-voltage winding. By measuring the secondary current on the low-voltage side and combining it with a special heating resistor, the change in the current signal is reflected in the change in the resistance value of the platinum resistance thermometer, thereby obtaining the temperature signal of the low-voltage winding.

[0069] The measurement and control device is used to collect the low-voltage side secondary current and low-voltage winding temperature signals. Based on the preset winding temperature response characteristic protection logic, it determines the magnitude of the low-voltage side secondary current relative to the preset value of the rated current within a preset time period. Based on the determination result, it selects the corresponding calculation formula and then calculates the temperature of the high-voltage winding based on the low-voltage winding temperature. The specific determination process is as follows:

[0070] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H , among which, T L T represents the low-voltage winding temperature. H △T represents the temperature of the high-voltage winding, and △T represents the temperature difference between the high-voltage and low-voltage windings calculated under the full-power operation of the transformer during the temperature rise test.

[0071] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0072] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current within the preset time period (set to 30 minutes), or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current within the preset time period (set to 30 minutes), does not exceed the preset duration (set to 20 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0073] If the time period within the preset time period (set to 30 minutes) during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset duration (set to 20 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0074] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset duration (set to 20 minutes) within the preset time period (30 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0075] At all times, T L ≥T H ≥T o .

[0076] Specifically, the measurement and control device includes a signal acquisition module, a signal conversion module, a signal processing module, a display module, and a data transmission module. The signal acquisition module is used to acquire the low-voltage side secondary current measured by the current transformer and the low-voltage winding temperature measured by the temperature sensor. The signal conversion module is used to convert the low-voltage side secondary current and low-voltage winding temperature signals into digital signals and transmit them to the signal processing module. The signal processing module is used to store the digital signals transmitted by the signal conversion module, determine the magnitude of the low-voltage side secondary current and the preset value of the rated current within a preset time period according to the preset winding temperature response characteristic protection logic, select the corresponding calculation formula according to the determination result, and then calculate the temperature of the high-voltage winding based on the low-voltage winding temperature. The display module is used to display the calculation results. The data transmission module is used to output the calculation results.

[0077] Specifically, the signal processing module includes a register module for storing data, a judgment module for making judgments based on the protection logic of the winding temperature response characteristics, and a calculation module for calculating the high-voltage winding temperature.

[0078] like Figure 2 As shown, the monitoring and control device sets the winding temperature response characteristic protection logic based on the temperature relationship between the high-voltage and low-voltage windings and the actual operating state of the transformer, specifically including:

[0079] First, calculate the temperature difference between the high-voltage and low-voltage windings:

[0080] During the temperature rise test, the difference between the applied current and the specified current is within ±10%. At the instant the power is disconnected, the average temperature rise of the winding above the average liquid temperature can be obtained by multiplying the test result by [I]. r / I t ] y Obtain, of which, I r I represents the rated current. t y represents the test current, and y represents the correction index for the temperature rise test results.

[0081] Transformers need to undergo a temperature rise test when they leave the factory. During the temperature rise test, the power of the transformer reaches 100%, and the temperature rise test equipment can monitor the test current of the high and low voltage windings.

[0082] By combining the test current and rated current of the high-voltage and low-voltage windings, and using the temperature formulas for the high-voltage and low-voltage windings, the temperatures of the high-voltage and low-voltage windings under full power of the transformer are calculated respectively.

[0083]

[0084]

[0085] Among them, T o T represents the temperature of the top layer of the transformer oil tank. L T represents the low-voltage winding temperature. H I represents the high-voltage winding temperature. rL I represents the rated current of the low-voltage winding. tL I represents the low-voltage winding test current. rH I represents the rated current of the high-voltage winding. tH This represents the test current of the high-voltage winding;

[0086] Next, based on the temperatures of the high-voltage and low-voltage windings, the temperature difference ΔT between the high-voltage and low-voltage windings is calculated as follows:

[0087] △T=T L -T H .

[0088] Next, determine the temperature relationship between the high-voltage and low-voltage windings:

[0089] Because the primary current of the low-voltage winding is higher than that of the high-voltage winding, the temperature T of the low-voltage winding is higher. L Always greater than the temperature T of the high-voltage winding H The temperature difference T between the high-voltage and low-voltage windings L -T H Defined as ΔT. According to transformer design, ΔT is basically 0 when the transformer power is low, and it usually gradually increases when the power increases to around 60%, reaching its maximum value when the transformer power is 100%.

[0090] Based on the temperature difference characteristics of the high-voltage and low-voltage windings, the temperature of the high-voltage winding can be approximated using the following formula:

[0091] When the transformer power is greater than or equal to 60% of the rated power, the high-voltage winding temperature T H The calculation formula is: T H =T L -△T;

[0092] When the transformer power is less than 60% of the rated power, the high-voltage winding temperature T H The calculation formula is: T H =T L .

[0093] Finally, the protection logic for the high-voltage winding temperature response characteristics is set according to the actual operating conditions of the transformer:

[0094] Actual transformer operating data shows that the transformer's power is not always at 100%, and the power fluctuations are significant.

[0095] Due to the speed of heat transfer response, changes in transformer power require additional time to be reflected in the winding temperature. To make the change in high-voltage winding temperature more consistent with actual conditions, therefore, the aforementioned high-voltage winding temperature T... H Based on the calculation formula, hysteresis control is used to set the protection logic for the high voltage winding temperature response characteristics for the high voltage winding temperature calculation.

[0096] like Figure 3 As shown, the hysteresis control settings are as follows:

[0097] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H ;

[0098] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0099] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current within the preset time period (set to 30 minutes), or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current within the preset time period (set to 30 minutes), does not exceed the preset duration (set to 20 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0100] If the time period within the preset time period (set to 30 minutes) during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset duration (set to 20 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0101] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset duration (set to 20 minutes) within the preset time period (30 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0102] At all times, T L ≥T H ≥T o .

[0103] Example 2:

[0104] This embodiment provides a method for measuring the temperature of the high-voltage winding of an oil-immersed transformer, utilizing the aforementioned oil-immersed transformer high-voltage winding temperature measuring device, including the following steps:

[0105] S1. Connect the current transformer and temperature sensor to the low-voltage side of the transformer respectively;

[0106] S2. Connect the transformer to the power grid and operate it according to the actual working conditions;

[0107] S3. Measure the secondary current on the low-voltage side of the transformer and the temperature signal of the low-voltage winding using a current transformer and a temperature sensor, respectively.

[0108] S4. The low-voltage side secondary current and low-voltage winding temperature signals are collected by the measurement and control device. The magnitude of the low-voltage side secondary current and the rated current preset value within the preset time period is judged according to the preset winding temperature response characteristic protection logic. The corresponding calculation formula is selected according to the judgment result, and then the temperature of the high-voltage winding is calculated according to the low-voltage winding temperature.

[0109] S5. The calculated high-voltage winding temperature is displayed and transmitted through the measurement and control device.

[0110] Specifically, step S4 includes the following steps:

[0111] If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L -△T is used to calculate the high-voltage winding temperature T. H ;

[0112] If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period (set to 30 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0113] If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current within the preset time period (set to 30 minutes), or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current within the preset time period (set to 30 minutes), does not exceed the preset duration (set to 20 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0114] If the time period within the preset time period (set to 30 minutes) during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset duration (set to 20 minutes), then according to the calculation formula T... H =T L Calculate the high-voltage winding temperature T H ;

[0115] If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset duration (set to 20 minutes) within the preset time period (30 minutes), then the high-voltage winding temperature T will continue to be calculated according to the formula from the previous preset time period. H ;

[0116] At all times, T L ≥T H ≥To .

[0117] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A temperature measuring device for the high-voltage winding of an oil-immersed transformer, characterized in that: Includes current transformers, temperature sensors, and measurement and control devices; The current transformer is used to measure the secondary current on the low-voltage side of the transformer; The temperature sensor is used to measure the temperature signal of the low-voltage winding of the transformer; The measurement and control device is used to collect the low-voltage side secondary current and low-voltage winding temperature signals. Based on a preset winding temperature response characteristic protection logic, it determines the magnitude of the low-voltage side secondary current relative to the preset value of the rated current within a preset time period. Based on the determination result, it selects the appropriate calculation formula and then calculates the high-voltage winding temperature based on the low-voltage winding temperature. The measurement and control device sets the winding temperature response characteristic protection logic according to the temperature relationship between the high- and low-voltage windings and the actual operating state of the transformer, as detailed below: First, calculate the temperature difference between the high-voltage and low-voltage windings: During transformer temperature rise testing, the temperatures of the high-voltage and low-voltage windings at full power are calculated using the test currents and rated currents of the high-voltage and low-voltage windings, based on the temperature formulas for the high-voltage and low-voltage windings. ； ； in, This represents the temperature of the top layer of oil in the transformer tank. This represents the temperature of the low-voltage winding. This represents the high-voltage winding temperature. This represents the rated current of the low-voltage winding. This represents the test current for the low-voltage winding. This represents the rated current of the high-voltage winding. This represents the test current of the high-voltage winding; Calculate the temperature difference between the high-voltage and low-voltage windings based on their temperatures. for: ； Finally, the winding temperature response characteristic protection logic is set according to the actual operating conditions of the transformer: If the secondary current on the low-voltage side of the transformer exceeds 62% of the rated current for a period longer than the preset time period, then according to the calculation formula... Calculate the high voltage winding temperature ,in, This represents the temperature of the low-voltage winding. This represents the high-voltage winding temperature. This represents the temperature difference between the high-voltage and low-voltage windings calculated under full-power operation of the transformer during the temperature rise test. If the secondary current on the low-voltage side of the transformer is less than 59% of the rated current for a period exceeding the preset time period, then according to the calculation formula... Calculate the high voltage winding temperature ; If the time during which the secondary current on the low-voltage side of the transformer is greater than 62% of the rated current, or the time during which the secondary current on the low-voltage side of the transformer is less than 59% of the rated current, does not exceed the preset duration, then the high-voltage winding temperature will continue to be calculated according to the formula from the previous preset time period. ; If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current exceeds the preset time period, then according to the calculation formula... Calculate the high voltage winding temperature ; If the time during which the secondary current on the low-voltage side of the transformer is less than or equal to 62% of the rated current and greater than or equal to 59% of the rated current does not exceed the preset time period, then the high-voltage winding temperature will continue to be calculated according to the formula used in the previous preset time period. ; At all times, .

2. The oil-immersed transformer high-voltage winding temperature measuring device according to claim 1, characterized in that: The measurement and control device includes a signal acquisition module, a signal conversion module, a signal processing module, a display module, and a data transmission module. The signal acquisition module is used to acquire the low-voltage side secondary current measured by the current transformer and the low-voltage winding temperature measured by the temperature sensor. The signal conversion module is used to convert the low-voltage side secondary current and low-voltage winding temperature signals into digital signals and transmit them to the signal processing module. The signal processing module is used to store the digital signals transmitted by the signal conversion module, determine the magnitude of the low-voltage side secondary current and the preset value of the rated current within a preset time period according to the preset winding temperature response characteristic protection logic, select the corresponding calculation formula according to the determination result, and then calculate the temperature of the high-voltage winding based on the low-voltage winding temperature. The display module is used to display the calculation results; The data transmission module is used to output the calculation results.

3. The oil-immersed transformer high-voltage winding temperature measuring device according to claim 2, characterized in that: The signal processing module includes a register module for storing data, a judgment module for making protection logic judgments based on the winding temperature response characteristics, and a calculation module for calculating the high-voltage winding temperature.

4. The oil-immersed transformer high-voltage winding temperature measuring device according to claim 1, characterized in that: The current transformer is located on the low-voltage side of the transformer.

5. The oil-immersed transformer high-voltage winding temperature measuring device according to claim 1, characterized in that: The temperature sensor is located on the low-voltage side of the transformer.

6. A method for measuring the temperature of the high-voltage winding of an oil-immersed transformer, characterized in that, The method of using the oil-immersed transformer high-voltage winding temperature measuring device according to any one of claims 1 to 5 includes the following steps: S1. Connect the current transformer and temperature sensor to the low-voltage side of the transformer respectively; S2. Connect the transformer to the power grid and operate it according to the actual working conditions; S3. Measure the secondary current on the low-voltage side of the transformer and the temperature signal of the low-voltage winding using a current transformer and a temperature sensor, respectively. S4. The low-voltage side secondary current and low-voltage winding temperature signals are collected by the measurement and control device. The magnitude of the low-voltage side secondary current and the rated current preset value within the preset time period is judged according to the preset winding temperature response characteristic protection logic. The corresponding calculation formula is selected according to the judgment result, and then the temperature of the high-voltage winding is calculated according to the low-voltage winding temperature. S5. The calculated high-voltage winding temperature is displayed and transmitted through the measurement and control device.

7. The method for measuring the temperature of the high-voltage winding of an oil-immersed transformer according to claim 6, characterized in that: The preset time period is 30 minutes, and the preset duration is 20 minutes.

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