Oil-immersed transformer and temperature detector thereof
By adopting the oil-phase temperature measurement component with temperature bulb protection and the self-test mechanism of the TEC thermostat in the oil-immersed transformer, the problem of inaccurate temperature detection caused by thermistor failure is solved, and the accuracy and low maintenance of oil-immersed transformer temperature detection are achieved.
Patent Information
- Application Number
- CN202422867962.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2034-11-22
AI Technical Summary
In the prior art, when a temperature detector of an oil-immersed transformer directly measures the upper oil temperature through a thermistor, if the thermistor fails, the detection result may be inaccurate.
The oil-phase temperature measurement assembly, protected by a temperature bulb, includes a TEC thermostat and multiple temperature sensors. A self-check mechanism prevents sensor failure, the TEC thermostat maintains a stable oil temperature, and the winding temperature is accurately calculated through self-checking and calibration of multiple temperature sensors.
The system realizes self-calibration of the temperature sensor without power outage of the oil-immersed transformer, thereby preventing errors, reducing maintenance costs, and improving the accuracy and rationality of temperature detection.
Smart Images
Figure CN223485329U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of transformer technology, and in particular to an oil-immersed transformer and its temperature detector. Background Technology
[0002] Long-term operation of oil-immersed transformers at high temperatures accelerates oil deterioration, leading to insulation degradation and ultimately transformer damage. Therefore, a temperature detector is needed to continuously monitor the temperature of the oil-immersed transformer. The temperature of the oil-immersed transformer is reflected in the winding temperature T, which is the sum of the upper oil temperature T1 and the winding temperature rise ΔT, i.e., T = T1 + ΔT. In the existing technology, the upper oil temperature T1 of the oil-immersed transformer is directly measured by a thermistor installed in the upper oil phase of the transformer. However, if the thermistor malfunctions during the direct measurement of the upper oil temperature of the oil-immersed transformer, the measured upper oil temperature T1 will have errors, resulting in inaccurate final results from the temperature detector. Summary of the Invention
[0003] In view of this, it is necessary to provide a temperature detector for oil-immersed transformers to solve the technical problem that if the thermistor placed in the upper oil phase of the oil-immersed transformer fails during the direct measurement of the upper oil temperature, the detected upper oil temperature T1 will have an error, resulting in inaccurate final results from the temperature detector.
[0004] It is also necessary to provide an oil-immersed transformer.
[0005] On one hand, this utility model provides a temperature detector for an oil-immersed transformer, including a temperature bulb, an oil phase temperature measuring component, and a main unit. The temperature bulb is hollow inside, and an oil phase exchange hole is opened on the side end of the temperature bulb. The temperature bulb is immersed in the upper oil phase of the oil-immersed transformer. The oil phase temperature measuring component is suspended in the temperature bulb and electrically connected to the main unit. The oil phase temperature measuring component includes a TEC temperature controller and a temperature sensor. The TEC temperature controller has at least three receiving grooves, and the number of temperature sensors is the same as the number of receiving grooves. The temperature sensors are located in the receiving grooves. The TEC temperature controller and the temperature sensors are both electrically connected to the main unit. The upper oil phase of the oil-immersed transformer enters the temperature bulb through the oil phase exchange hole. The receiving grooves enclose and drive the temperature sensor to be immersed in the oil phase in the temperature bulb for temperature measurement.
[0006] Preferably, the temperature sensor can be an optical fiber temperature sensor, a PT100 temperature sensor, or a thermocouple temperature sensor.
[0007] Preferably, the temperature detector of the oil-immersed transformer further includes a winding temperature measuring component, which is electrically connected to the main unit and also electrically connected to the a, b, and c phase windings of the oil-immersed transformer.
[0008] Preferably, the winding temperature measurement assembly includes three current transformers, three current sensors, and a three-channel analog-to-digital converter. The three current transformers are electrically connected to the a, b, and c phase windings of the oil-immersed transformer, respectively. The input terminals of the three current sensors are electrically connected to the secondary coils of the three current transformers, respectively. The output terminals of the three current sensors are all electrically connected to the three-channel analog-to-digital converter, and the three-channel analog-to-digital converter is electrically connected to the host computer.
[0009] On the other hand, this utility model also provides an oil-immersed transformer, including the temperature detector of the oil-immersed transformer described in the previous aspect.
[0010] As can be seen from the above technical solution, the temperature detector for oil-immersed transformers provided by this utility model includes a temperature bulb, an oil phase temperature measuring component, and a main unit. The temperature bulb is hollow inside, and an oil phase exchange hole is opened on the side end of the temperature bulb. The temperature bulb is immersed in the upper oil phase of the oil-immersed transformer. The oil phase temperature measuring component is suspended in the temperature bulb to protect the oil phase temperature measuring component from damage or malfunction. The oil phase temperature measuring component is electrically connected to the main unit and includes a TEC temperature controller and a temperature sensor. The TEC temperature controller has at least three receiving grooves, and the number of temperature sensors is the same as the number of receiving grooves. The temperature sensors are located in the receiving grooves. Both the TEC temperature controller and the temperature sensors are electrically connected to the main unit. The upper oil phase of the oil-immersed transformer enters the temperature bulb through the oil phase exchange hole, and the receiving grooves enclose and move the temperature sensors. Temperature measurement is performed on the oil phase immersed in the temperature sensor. Before measuring the oil temperature of the upper oil phase of the oil-immersed transformer, one of the temperature sensors measures the temperature of the temperature sensor and transmits the detected temperature to the host. The host compares the detected temperature with the set temperature. If the detected temperature is lower than the set temperature, the TEC temperature controller heats up the oil in the temperature sensor to the set temperature. If the detected temperature is higher than the set temperature, the TEC temperature controller cools down the oil in the temperature sensor to the set temperature. After the oil temperature in the temperature sensor reaches the set temperature, the temperature sensor measures the oil temperature in the temperature sensor and obtains at least three self-test temperatures, which are transmitted to the host. The host compares the at least three self-test temperatures. If a self-test temperature that is different from the majority of the self-test temperatures appears, the host determines that the temperature sensor has failed, thus preventing errors caused by temperature sensor failure that could lead to inaccurate results from the temperature detector of the oil-immersed transformer. Attached Figure Description
[0011] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 This is a cross-sectional view of the oil phase temperature measurement component.
[0013] Figure 2 This is a schematic diagram of the connection of a temperature detector for an oil-immersed transformer.
[0014] In the diagram: Temperature bulb 1, oil phase exchange port 11, oil phase temperature measurement component 2, TEC temperature controller 21, receiving groove 211, first temperature sensor 22, second temperature sensor 23, third temperature sensor 24, main unit 3, oil phase temperature data processing module 31, winding temperature data processing module 32, communication module 33, winding temperature measurement component 4, current transformer 41, current sensor 42, three-channel analog-to-digital converter 43. Detailed Implementation
[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0016] In the description of this utility model, it should be understood that the terms "upper", "middle", "outer", "inner", "lower", etc., which indicate orientation or positional relationship, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0017] Please refer to Figure 1-2On the one hand, the present invention provides a temperature detector for an oil-immersed transformer, including a temperature bulb 1, an oil phase temperature measuring component 2, and a main unit 3. The temperature bulb 1 is hollow inside, and an oil phase exchange hole 11 is opened on the side end of the temperature bulb 1. The temperature bulb 1 is immersed in the upper oil phase of the oil-immersed transformer. The oil phase temperature measuring component 2 is suspended in the temperature bulb so that the temperature bulb 1 protects the oil phase temperature measuring component 2 from damage or malfunction. The oil phase temperature measuring component 2 is electrically connected to the main unit 3. The oil phase temperature measuring component 2 includes a TEC temperature controller 21, a... Temperature sensor 22, temperature sensor 23, and temperature sensor 24 are located on a TEC temperature controller 21, which has three receiving grooves 211. The TEC temperature controller 21, temperature sensor 22, temperature sensor 23, and temperature sensor 24 are respectively located within the three receiving grooves 211. All three temperature sensors 24 are electrically connected to the main unit 3. The upper oil phase of the oil-immersed transformer enters the temperature bulb 1 through the oil phase exchange hole 11. The receiving grooves 211 enclose and move the first temperature sensor. 22. The second temperature sensor 23 and the third temperature sensor 24 are both immersed in the oil phase inside the temperature-controlled bulb 1 for temperature measurement. Before measuring the oil temperature of the upper oil phase of the oil-immersed transformer, the first temperature sensor 22 measures the temperature of the temperature-controlled bulb 1 and transmits the detected temperature to the host unit 3. The host unit 3 compares the detected temperature with the set temperature. If the detected temperature is lower than the set temperature, the TEC temperature controller 21 heats up the oil in the temperature-controlled bulb 1 to raise the temperature to the set temperature. If the detected temperature is higher than the set temperature, the TEC temperature controller 21 cools down the oil in the temperature-controlled bulb 1 to lower the temperature to the set temperature. After the oil temperature in the temperature chamber 1 reaches the set temperature, the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24 all measure the oil temperature in the temperature chamber 1 to obtain the first self-test temperature, the second self-test temperature, and the third self-test temperature, and transmit them to the host 3. The host 3 compares the first self-test temperature, the second self-test temperature, and the third self-test temperature. If a self-test temperature that is different from the majority of the self-test temperatures appears, the host 3 can determine that the temperature sensor has failed, thus preventing the temperature sensor from malfunctioning and causing errors that would lead to inaccurate final results from the temperature detector of the oil-immersed transformer.
[0018] In one embodiment, the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24 can all be fiber optic temperature sensors, PT100 temperature sensors, or thermocouple temperature sensors.
[0019] In one embodiment, the host 3 includes an oil phase temperature data processing module 31. A TEC temperature controller 21, a first temperature sensor 22, a second temperature sensor 23, and a third temperature sensor 24 are all electrically connected to the oil phase temperature data processing module 31. Before measuring the oil temperature of the upper oil phase of the oil-immersed transformer, the first temperature sensor 22 measures the temperature of the temperature bulb 1 and transmits the detected temperature to the oil phase temperature data processing module 31. The oil phase temperature data processing module 31 compares the detected temperature with the set temperature and controls the TEC temperature controller 21 to either raise or lower the temperature to the set temperature. At this time, the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24 measure the oil temperature inside the temperature bulb 1 to obtain a first self-test result. The temperature, the second self-test temperature, and the third self-test temperature are transmitted to the oil phase temperature data processing module 31. The oil phase temperature data processing module 31 compares the first self-test temperature, the second self-test temperature, and the third self-test temperature. If a temperature is different from the majority of self-test temperatures, the oil phase temperature data processing module 31 can determine that the temperature sensor has failed. For example, when the first self-test temperature is 50°C, the second self-test temperature is 45°C, and the third self-test temperature is 50°C, the oil phase temperature data processing module 31, based on the analysis that the second self-test temperature of 45°C is different from the majority of the first and third self-test temperatures of 50°C, determines that the second temperature sensor 23 has failed, while the first temperature sensor 22 and the third temperature sensor 24 are working normally.
[0020] Furthermore, the oil phase temperature data processing module 31 can calculate the error value generated by the faulty temperature sensor based on the first self-test temperature, the second self-test temperature, and the third self-test temperature. For example, when the first self-test temperature is 50℃, the second self-test temperature is 45℃, and the third self-test temperature is 50℃, the oil phase temperature data processing module 31, based on the analysis that the second self-test temperature of 45℃ is different from most of the first and third self-test temperatures of 50℃, calculates that the error value between the second self-test temperature of 45℃ and the first or third self-test temperature of 50℃ is -5℃.
[0021] Furthermore, after a certain period of settling to allow the oil temperature inside the temperature chamber 1 to match the upper oil temperature of the oil-immersed transformer, the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24 respectively measure the oil temperature inside the temperature chamber 1 to obtain the first oil phase temperature, the second oil phase temperature, and the third oil phase temperature, and transmit them to the oil phase temperature data processing module 31. The oil phase temperature data processing module 31 can calibrate the relevant temperature sensors based on the calculated error value, and process the calibrated first oil phase temperature, second oil phase temperature, and third oil phase temperature. The average value is taken to obtain the upper oil temperature T1 of the oil-immersed transformer, thereby preventing errors caused by malfunctions in the temperature sensing unit that could lead to inaccurate results from the temperature detector of the oil-immersed transformer. For example, when the error value of the second temperature sensor 23 is -5℃, the first oil phase temperature is 80℃, the second oil phase temperature is 75℃, and the third oil phase temperature is 80℃, the oil phase temperature data processing module 31 calibrates the second oil phase temperature to 75℃ based on the error value of the second temperature sensor 23 of -5℃, thereby calibrating the second oil phase temperature to 80℃.
[0022] In this invention, the oil phase temperature data processing module 31 can use an STM32F407 chip, and the TEC temperature controller 21 is existing technology. Its principle utilizes the Peltier effect of semiconductor materials. The Peltier effect refers to the phenomenon that when a direct current passes through a thermocouple composed of two semiconductor materials, one end absorbs heat and the other end releases heat. Heavily doped N-type and P-type bismuth telluride are mainly used as the semiconductor materials for the TEC temperature controller 21. The bismuth telluride elements are connected in series and generate heat in parallel. The TEC temperature controller 21 includes some P-type and... The N-type pairs (groups) are connected together by electrodes and sandwiched between two ceramic electrodes. When current flows through the TEC temperature controller 21, the heat generated by the current is transferred from one side of the TEC temperature controller to the other side, creating a "hot" side and a "cold" side on the TEC temperature controller. When the detected temperature is lower than the set temperature, the TEC temperature controller 21 raises the oil temperature inside the temperature bulb 1 to the set temperature through a forward current. When the detected temperature is higher than the set temperature, the TEC temperature controller 21 cools the oil temperature inside the temperature bulb 1 to the set temperature through a reverse current.
[0023] In one embodiment, in order to accurately measure the winding temperature rise ΔT of the oil-immersed transformer, the main unit 3 further includes a winding temperature data processing module 32, which is electrically connected to the oil phase temperature data processing module 31. The temperature detector of the oil-immersed transformer also includes a winding temperature measuring component 4, which is electrically connected to the winding temperature data processing module 32 and is also electrically connected to the a, b, and c phase windings of the oil-immersed transformer.
[0024] In one embodiment, the winding temperature measurement assembly 4 includes three current transformers 41, three current sensors 42, and a three-channel analog-to-digital converter 43. The three current transformers 41 are electrically connected to the a, b, and c phase windings of the oil-immersed transformer, respectively. The input terminals of the three current sensors 42 are electrically connected to the secondary coils of the three current transformers 41, respectively. The output terminals of the three current sensors 42 are all electrically connected to the three-channel analog-to-digital converter 43. The three-channel analog-to-digital converter 43 is electrically connected to the winding temperature data processing module 32. The three current sensors 42 respectively transmit the data from the three current transformers 41, 42, and 43. The amplitude of the secondary current of the transformer 1 is converted into a voltage signal. The three-channel analog-to-digital converter 43 performs three-channel parallel acquisition of the output voltages of the three current sensors 42, which can simultaneously obtain the winding current values Ia, Ib, and Ic of the three phases a, b, and c of the oil-immersed transformer and transmit them to the winding temperature data processing module 32. The winding temperature data processing module 32 calculates the actual operating current of the three phases a, b, and c of the oil-immersed transformer based on the turns ratio of the three current transformers 41, and uses the heat generation calculation formula ΔT=K×I based on the theory that heat generation is proportional to the square of the current. 2 The winding temperature rise ΔT caused by the actual winding current is calculated. The winding temperature of the oil-immersed transformer is approximately equal to the sum of the upper oil temperature T1 and the winding temperature rise ΔT. The oil phase temperature data processing module 31 transmits the upper oil temperature T1 of the oil-immersed transformer to the winding temperature data processing module 32. Therefore, the actual temperature values Ta, Tb, and Tc of the three-phase windings a, b, and c of the oil-immersed transformer can be calculated through the winding temperature data processing module 32.
[0025] In one embodiment, the host 3 further includes a communication module 33, which is electrically connected to the oil phase temperature data processing module 31 and the winding temperature data processing module 32. The communication module 33 can send the temperature measurement data of the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24, as well as the actual temperature values Ta, Tb, and Tc of the three-phase windings a, b, and c of the oil-immersed transformer, to a remote server in the transformer's main control room. The remote server can understand the working status of each temperature sensor based on the temperature measurement data of the first temperature sensor 22, the second temperature sensor 23, and the third temperature sensor 24, and compare the actual temperature values Ta, Tb, and Tc of the three-phase windings a, b, and c of the oil-immersed transformer with the temperature threshold. When the actual temperature values Ta, Tb, and Tc of the three-phase windings a, b, and c of the oil-immersed transformer exceed the temperature threshold, the remote server will issue an alarm signal to remind maintenance personnel to check.
[0026] In this invention, the communication module 33 can be a Bluetooth module, a WiFi module, a LoRa module, an NB-IoT module, or a 3G / 4G / 5G module.
[0027] In summary, the temperature detector for oil-immersed transformers according to this utility model embodiment can perform on-site temperature sensor self-calibration without power interruption of the oil-immersed transformer. This prevents errors caused by temperature sensor malfunctions from leading to inaccurate final results from the temperature detector, reduces the on-site calibration cost of the temperature detector, and significantly reduces the subsequent maintenance of the temperature detector, achieving a maintenance-free state. Furthermore, it provides more reasonable and accurate measurement of the winding temperature of the oil-immersed transformer.
[0028] On the other hand, this utility model also provides an oil-immersed transformer, including the temperature detector of the oil-immersed transformer described in the previous aspect.
[0029] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the utility model.
Claims
1. A temperature detector for an oil-immersed transformer, characterized in that: The device includes a temperature bulb, an oil phase temperature measuring component, and a main unit. The temperature bulb is hollow inside, and an oil phase exchange hole is opened on its side. The temperature bulb is immersed in the upper oil phase of an oil-immersed transformer. The oil phase temperature measuring component is suspended in the temperature bulb and electrically connected to the main unit. The oil phase temperature measuring component includes a TEC temperature controller and a temperature sensor. The TEC temperature controller has at least three receiving grooves, and the number of temperature sensors is the same as the number of receiving grooves. The temperature sensors are located in the receiving grooves. The TEC temperature controller and the temperature sensors are both electrically connected to the main unit. The upper oil phase of the oil-immersed transformer enters the temperature bulb through the oil phase exchange hole. The receiving grooves enclose and drive the temperature sensor to be immersed in the oil phase in the temperature bulb for temperature measurement.
2. The temperature detector for an oil-immersed transformer as described in claim 1, characterized in that: The temperature sensor can be a fiber optic temperature sensor, a PT100 temperature sensor, or a thermocouple temperature sensor.
3. The temperature detector for an oil-immersed transformer as described in claim 1 or 2, characterized in that: The temperature detector of the oil-immersed transformer also includes a winding temperature measuring component, which is electrically connected to the main unit and also electrically connected to the a, b, and c phase windings of the oil-immersed transformer.
4. The temperature detector for an oil-immersed transformer as described in claim 3, characterized in that: The winding temperature measurement assembly includes three current transformers, three current sensors, and a three-channel analog-to-digital converter. The three current transformers are electrically connected to the a, b, and c phase windings of the oil-immersed transformer, respectively. The input terminals of the three current sensors are electrically connected to the secondary coils of the three current transformers, respectively. The output terminals of the three current sensors are all electrically connected to the three-channel analog-to-digital converter, which is electrically connected to the main unit.
5. An oil-immersed transformer, characterized in that: Including the temperature detector for an oil-immersed transformer as described in any one of claims 1-4.