Transformer with auxiliary iron core structure and adjustable micro-water control method thereof
By setting the auxiliary iron core and heating winding in the transformer, combined with the data input of the detection unit, dynamic removal of the micro water in the transformer oil is achieved, which solves the problem of reduced insulation performance and equipment failure caused by micro water, and extends the service life of the equipment.
Patent Information
- Application Number
- CN202411901984.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-03-18
AI Technical Summary
The microwater in the transformer oil will reduce insulation performance, resulting in insulation breakdown, local discharge and equipment failure, and the microwater accelerates the oxidation and aging of the oil, shortening the service life of the equipment.
By setting an auxiliary iron core and heating winding on the upper and lower iron yokes of the transformer, the detection unit is used to detect the oil temperature and microwater content, and the working state of the heating winding is controlled according to different working conditions, so as to evaporate and remove microwater in the transformer oil.
It effectively avoids the safety impact of microwater on the transformer operation, extends the service life of the equipment, and improves the insulation performance of the transformer.
Smart Images
Figure CN119650255A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of transformers, and in particular to a transformer with an auxiliary iron core structure and an adjustable micro-water control method thereof. Background Art
[0002] Transformers are vital equipment in power systems, and their normal operation is crucial to the stability and safety of power systems. Controlling the water content in transformer oil is one of the key factors to ensure the insulation performance and service life of transformers. Transformer oil paper itself contains trace amounts of moisture. Especially in the extremely cold weather in the north, the moisture in transformer oil paper is easily precipitated into transformer oil. At the same time, transformers also absorb moisture from the air during transportation, storage and operation. Water in transformer oil can significantly reduce the insulation performance of the oil. Water will be polarized under the action of an electric field, which may lead to insulation breakdown and partial discharge, and in severe cases may cause equipment failure. Water content will also accelerate the oxidation and aging of the oil, generating acidic substances and sludge, which may corrode metal parts inside the transformer and shorten the service life of the equipment. Therefore, the control of transformer water content is crucial for the safe operation of the transformer.
[0003] Therefore, in view of the above-mentioned technical problems, it is necessary to provide a transformer with an auxiliary iron core structure and an adjustable micro-water control method. Summary of the invention
[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a transformer with an auxiliary iron core structure and an adjustable micro-water control method. According to the different ways in which micro-water exists in the transformer, the different forms of micro-water existing inside the transformer are eliminated by controlling the opening and closing of different iron core windings, thereby solving the problem of transformer operation failure.
[0005] To achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention proposes a transformer with an auxiliary iron core structure. The transformer is an oil-immersed transformer. The upper iron yoke and the lower iron yoke of the transformer core are both laterally provided with auxiliary iron cores. A group of heating windings are installed on each auxiliary iron core, and each group of heating windings is connected to a group of independent driving units. A group of driving units includes an independent AC power supply and a controllable switch. The independent AC power supply is connected to a group of heating windings through a controllable switch. The control ends of the controllable switches of the two groups of driving units are connected to a common control unit. The input end of the control unit is connected to a detection unit. The detection unit includes a temperature sensor, an upper humidity sensor and a lower humidity sensor. The temperature sensor, the upper humidity sensor and the lower humidity sensor are connected to the control unit through a signal processing circuit. The temperature sensor extends into the transformer oil, and the upper humidity sensor and the lower humidity sensor extend into the upper and lower parts of the transformer oil respectively. The control unit, the detection unit and the two controllable switches constitute a control loop.
[0006] Preferably, the controllable switch is an IGBT switch element, and an input end of the IGBT switch element is connected to a control unit.
[0007] Preferably, a group of the heating windings includes two horizontally symmetrically arranged windings, and the two horizontally symmetrically arranged windings are connected in series.
[0008] Preferably, the temperature measurement range of the temperature sensor is -200°C~850°C, and the output analog signal is 4-20mA; the humidity measurement range of the upper humidity sensor and the lower humidity sensor is 0% - 100% RH, and the humidity accuracy is ±1.5% RH.
[0009] Preferably, the control unit includes a communication unit and a lower computer, the lower computer includes a digital-to-analog conversion module and a signal processing module, the input end of the digital-to-analog conversion module is connected to the detection unit, the output end of the digital-to-analog conversion module is connected to the input end of the signal processing module, and the signal processing module is connected to the upper computer via the communication unit. A second aspect of the present invention provides an adjustable micro-water control method based on the above transformer, the method comprising the following steps: Step 1: Detect the data of transformer oil temperature T and trace water content A through the detection unit, and transmit the data to the control unit; Step 2: The control unit sets the working conditions of the two groups of heating windings through the driving unit according to the data of the transformer oil temperature T and the trace water content A in step 1. The process is as follows: Working condition 1: When the temperature sensor of the detection unit detects that the transformer oil temperature T is less than -30℃, and the upper humidity sensor and the lower humidity sensor both detect that the transformer oil micro-water content A is greater than 35ppm, the control unit turns on the two controllable switches at the same time, and the heating windings located at the upper iron yoke and the lower iron yoke are connected to their own independent AC power supplies to heat the transformer oil to evaporate the micro-water in the transformer oil, until the upper humidity sensor and the lower humidity sensor both detect that the transformer oil micro-water content A is less than 5ppm, the control unit turns off the two sets of controllable switches, and the heating windings located at the upper iron yoke and the lower iron yoke stop heating, and the residual heat of the auxiliary iron core is used to evaporate all the remaining micro-water; Working condition 2: When the temperature sensor of the detection unit detects that the transformer oil temperature T is less than -30℃, and the upper humidity sensor and the lower humidity sensor both detect that the transformer oil micro-water content is 5 ppm ≤A≤35ppm, the control unit turns on the lower controllable switch, and the heating winding of the lower iron yoke is connected to the AC power supply to heat the lower part of the transformer oil; until the upper humidity sensor and the lower humidity sensor both detect that the transformer oil micro-water content is A<5ppm, the control unit turns off the lower controllable switch, stops heating the heating winding of the lower iron yoke, and uses the residual heat of the auxiliary iron core to evaporate all the remaining micro-water; Working condition 3: When the temperature sensor of the detection unit detects that the transformer oil temperature T≧-30℃ and the upper humidity sensor detects that the transformer oil micro-water content A>35ppm, the control unit turns on the upper controllable switch, and the heating winding of the upper iron yoke is connected to the AC power supply to heat the upper part of the transformer oil; until the upper humidity sensor detects that the transformer oil micro-water content A<5ppm, the control unit turns off the upper controllable switch, stops heating the heating winding of the upper iron yoke, and uses the residual heat of the auxiliary iron core to evaporate all the remaining micro-water.
[0010] Beneficial effects: Compared with the prior art, the present invention can achieve the following technical effects: 1. When the transformer is working normally, if the water content in the cavity is detected to be above 35ppm, the transformer oil can be heated by the heating winding of the upper and lower iron yoke auxiliary iron core to evaporate the water in the transformer oil, thus avoiding the influence of the water in the transformer oil on the safe operation of the transformer.
[0011] 2. The transformer core winding is powered by the power grid, and the heating windings located at the top and bottom of the transformer are powered by independent power supplies. This ensures that the heating windings can work at the same time as the transformer operates normally. The transformer windings and the heating windings do not affect each other, thus avoiding interference with the operation of the transformer.
[0012] 3. The heating winding of the transformer is set with three working conditions. When the detection unit detects the presence of trace water inside the cavity, the heating windings at different positions can be controlled by the trace water evaporation control unit to deal with the trace water in the transformer oil according to the different ways and contents of the trace water generation.
[0013] 4. Compared with electric heating plates or heating wires, winding heating has higher energy conversion efficiency and can reduce the energy loss of external heating equipment. At the same time, because the winding is tightly integrated with the transformer and is more adaptable to the complex working environment inside the transformer, it avoids the problem of failure or damage of external heating elements, and has higher reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 A schematic diagram of the transformer structure of the auxiliary iron core structure of the present invention.
[0015] Figure 2 Schematic diagram of working condition 1 of the present invention.
[0016] Figure 3 Schematic diagram of working condition 2 of the present invention.
[0017] Figure 4 Schematic diagram of working condition 3 of the present invention.
[0018] Among them: 1 auxiliary winding; 2, independent AC power supply; 3, heating winding; 4, controllable switch; 5, control unit; 6 detection unit; 601, temperature sensor; 602, upper humidity sensor; 603, lower humidity sensor. DETAILED DESCRIPTION
[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings.
[0020] like Figure 1 As shown, the first aspect of the present invention provides a transformer with an auxiliary core structure, wherein the transformer is an oil-immersed transformer, wherein the upper and lower yokes of the transformer core are both laterally provided with auxiliary cores 1, each auxiliary core 1 is provided with a group of heating windings 3, each group of heating windings 3 is connected with a group of independent driving units, one group of driving units includes an independent AC power supply 2 and a controllable switch 4, the independent AC power supply 2 is connected to a group of heating windings 3 through the controllable switch 4, the control ends of the controllable switches 4 of the two groups of driving units are connected with a common control unit 5, the input end of the control unit 5 is connected with a detection unit 6, the detection unit 6 includes a temperature sensor 601, an upper humidity sensor 602 and a lower humidity sensor 603, The temperature sensor 601, the upper humidity sensor 602 and the lower humidity sensor 603 are connected to the control unit 5 through a signal processing circuit. The temperature sensor 601 extends into the transformer oil, and the upper humidity sensor 602 and the lower humidity sensor 603 extend into the upper and lower parts of the transformer oil respectively. The control unit 6, the detection unit 5 and the two controllable switches 4 constitute a control loop.
[0021] Among them, the heating winding 3 can be made of a material with a higher resistivity, and the heating is performed by utilizing the thermal effect after the conductor is energized. The auxiliary iron core can also be made of a whole metal rod structure (different from the laminated structure of the transformer iron core). At the same time, magnetic isolation measures are taken between the auxiliary iron core and the transformer iron core, and the eddy current formed by the electromagnetic induction of the auxiliary iron core is used to generate heat. The heat generated by the auxiliary iron core 1 and the heating winding 3 is used to evaporate the trace water in the transformer oil in a short time without affecting the normal operation of the transformer winding. When the temperature sensor detects that the temperature rises to 0°C, and the humidity sensor detects that the trace water content drops to 5ppm, the trace water is basically evaporated. After heating for another hour, the winding is disconnected and the residual heat of the iron core is used to evaporate all the remaining trace water.
[0022] Furthermore, the controllable switch 4 is an IGBT switch element, and an input end of the IGBT switch element is connected to the control unit 5 .
[0023] Furthermore, a group of the heating windings 3 includes two horizontally symmetrically arranged windings, and the two horizontally symmetrically arranged windings are connected in series.
[0024] Furthermore, the temperature measurement range of the temperature sensor 601 is -200°C~850°C, and the output analog signal is 4-20mA; the humidity measurement range of the upper humidity sensor 602 and the lower humidity sensor 603 is 0% - 100% RH, and the humidity accuracy is ±1.5% RH.
[0025] Furthermore, the control unit includes a communication unit and a lower computer, the lower computer includes a digital-to-analog conversion module and a signal processing module, the input end of the digital-to-analog conversion module is connected to the detection unit 6, the output end of the digital-to-analog conversion module is connected to the input end of the signal processing module, and the signal processing module is connected to the upper computer through the communication unit.
[0026] In this embodiment, the humidity detection unit adopts a humidity sensor of model SHT45-AD1B-R3, whose humidity measurement range is 0% - 100% RH, humidity accuracy is ±1.5% RH, temperature accuracy is ±0.1°C, and has the characteristics of providing additional protection options and being suitable for applications in harsh environments; the temperature detection unit adopts a temperature sensor of model SITRANS TS500, whose temperature measurement range is from the lowest temperature of -200°C to the highest temperature of 850°C, and the output analog signal is 4-20 mA or 0-10V; The digital signal processing module uses the TMS320F28075 chip with a maximum operating frequency of 120MHz; the digital-to-analog conversion module uses a 16-bit AD7606 digital-to-analog conversion chip with 6 channels sampling simultaneously. The operating voltage of AD7606 is +5V, and it supports true ±10V or ±5V bipolar signal input. All channels can be sampled at a rate of up to 200 kbps; the communication unit uses RS-422 serial communication bus, RS-422 uses differential signal transmission, and RS-422 supports full-duplex communication; the host computer uses VC++ program development environment and MS SQL Server relational database, and the installation and connection methods of each sensor are as follows: SHT45-AD1B-R3 humidity sensor is installed inside the transformer oil to detect the micro-water content inside the transformer oil; SITRANS The TS500 temperature sensor is installed inside the transformer oil to detect the internal temperature of the transformer oil. The three sensor signal output ends are connected to the AD7606 chip after passing through the signal processing circuit. The output end of the AD7606 chip is connected to the input end of the TMS320F28075 chip. The TMS320F28075 chip is connected to the computer through the RS-422 serial communication bus. The computer is used as the host computer to realize operations such as programming the slave computer.
[0027] Based on the above transformer, the present invention proposes an adjustable micro-water control method, which includes the following steps: Step 1: Detect the data of the compressor oil temperature T and the trace water content A through the detection unit 6, and transmit the data to the control unit 5; Step 2: The control unit 5 sets the working conditions of the two groups of heating windings through the driving unit according to the data of the transformer oil temperature T and the trace water content A in step 1. The process is as follows: Condition 1: If Figure 2 As shown, when the temperature sensor 601 of the detection unit 6 detects that the transformer oil temperature T is less than -30°C, and the upper humidity sensor 602 and the lower humidity sensor 603 both detect that the transformer oil micro-water content A is greater than 35ppm, at this time, the micro-water in the transformer oil mainly comes from the precipitation in the oil paper; the control unit 5 turns on the two controllable switches 4 at the same time, and the heating windings 3 located at the upper iron yoke and the lower iron yoke are connected to their respective independent AC power supplies 2 to heat the transformer oil to evaporate the micro-water in the transformer oil, until the upper humidity sensor 602 and the lower humidity sensor 603 both detect that the transformer oil micro-water content A is less than 5ppm, the control unit 5 turns off the two sets of controllable switches 4, stops heating the heating windings 3 located at the upper iron yoke and the lower iron yoke, and uses the residual heat of the auxiliary iron core 1 to evaporate all the remaining micro-water; Condition 2: If Figure 3 As shown, when the temperature sensor 601 of the detection unit 6 detects that the transformer oil temperature T is less than -30°C, and the upper humidity sensor 602 and the lower humidity sensor 603 both detect that the transformer oil micro-water content is 5 ppm ≤A ≤35ppm, at this time, the micro-water in the transformer oil mainly comes from the precipitation in the oil paper and the amount of precipitation is small. Due to the heat transfer effect, only the heating winding 3 of the lower iron yoke needs to be heated, and the control unit 5 turns on the lower controllable switch 4, and the heating winding 3 of the lower iron yoke is connected to the AC power supply 2 to heat the lower part of the transformer oil; until the upper humidity sensor 602 and the lower humidity sensor 603 both detect that the transformer oil micro-water content A is less than 5ppm, the control unit 5 turns off the lower controllable switch 4, stops heating the heating winding 3 of the lower iron yoke, and uses the residual heat of the auxiliary iron core 1 to evaporate all the remaining micro-water; Condition 3: If Figure 4 As shown, when the temperature sensor 601 of the detection unit 6 detects that the transformer oil temperature T≧-30°C, and the upper humidity sensor 602 detects that the transformer oil micro-water content A>35ppm, at this time, the micro-water in the transformer oil mainly comes from the dissolution of water in the external air, and at this time the micro-water mainly exists in the upper part of the transformer oil, the control unit 5 turns on the upper controllable switch 4, and the heating winding 3 of the upper iron yoke is connected to the AC power supply 2 to heat the upper part of the transformer oil; until the upper humidity sensor 602 detects that the transformer oil micro-water content A<5ppm, the heating winding 3 of the upper iron yoke stops heating, and the residual heat of the auxiliary iron core 1 is used to evaporate all the remaining micro-water.
[0028] When the two humidity sensors 6 detect that the moisture content of the transformer oil is less than 5 ppm, the heating windings 3 of the upper iron yoke and the lower iron yoke are not heated.
[0029] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of the present invention is limited only by the appended claims.
Claims
1. A transformer with an auxiliary core structure, the transformer being an oil-immersed transformer, characterized in that: The upper iron yoke and the lower iron yoke of the transformer iron core are both transversely provided with auxiliary iron cores (1), each auxiliary iron core (1) is mounted with a group of heating windings (3), each group of heating windings (3) is connected to a group of independent driving units, one group of driving units comprises an independent AC power supply (2) and a controllable switch (4), the independent AC power supply (2) is connected to a group of heating windings (3) via the controllable switch (4), the control ends of the controllable switches (4) of the two groups of driving units are connected to a common control unit (5), the input end of the control unit (5) is connected to a detection unit (6), the detection unit (6) The detection unit (6) comprises a temperature sensor (601), an upper humidity sensor (602) and a lower humidity sensor (603); the temperature sensor (601), the upper humidity sensor (602) and the lower humidity sensor (603) are connected to the control unit (5) via a signal processing circuit; the temperature sensor (601) extends into the interior of the transformer oil; the upper humidity sensor (602) and the lower humidity sensor (603) extend into the upper part and the lower part of the transformer oil respectively; the control unit (6), the detection unit (5) and the two controllable switches (4) form a control loop.
2. The transformer with an auxiliary iron core structure according to claim 1, characterized in that: The controllable switch (4) is an IGBT switch element, and an input end of the IGBT switch element is connected to a control unit (5).
3. The transformer with an auxiliary iron core structure according to claim 1, characterized in that: A group of the heating windings (3) comprises two horizontally symmetrically arranged windings, and the two horizontally symmetrically arranged windings are connected in series.
4. The transformer with an auxiliary iron core structure according to claim 1, characterized in that: The temperature sensor (601) has a temperature measurement range of -200°C to 850°C, and an output analog signal of 4-20mA; the upper humidity sensor (602) and the lower humidity sensor (603) have a humidity measurement range of 0% to 100% RH, and a humidity accuracy of ±1.5% RH.
5. The transformer with an auxiliary iron core structure according to claim 4, characterized in that: The control unit comprises a communication unit and a lower computer, the lower computer comprises a digital-to-analog conversion module and a signal processing module, the input end of the digital-to-analog conversion module is connected to the detection unit (6), the output end of the digital-to-analog conversion module is connected to the input end of the signal processing module, and the signal processing module is connected to the upper computer via the communication unit.
6. An adjustable micro-water control method for a transformer as claimed in claim 1, characterized in that: The method comprises the following steps: Step 1: Detecting data of transformer oil temperature T and trace water content A through the detection unit (6), and transmitting the data to the control unit (5); Step 2: The control unit (5) sets the working conditions of the two sets of heating windings through the driving unit according to the data of the transformer oil temperature T and the trace water content A in step 1. The process is as follows: Working condition 1: when the temperature sensor (601) of the detection unit (6) detects that the transformer oil temperature T is less than -30°C, and the upper humidity sensor (602) and the lower humidity sensor (603) both detect that the transformer oil micro-water content A is greater than 35 ppm, the control unit (5) causes the two controllable switches (4) to be turned on at the same time, and the heating windings (3) located at the upper iron yoke and the lower iron yoke are both connected to their own independent AC power supplies (2) to heat the transformer oil and evaporate the micro-water in the transformer oil until the upper humidity sensor (602) and the lower humidity sensor (603) both detect that the transformer oil micro-water content A is less than 5 ppm, and the control unit (5) causes the two sets of controllable switches (4) to be turned off, and the heating windings (3) located at the upper iron yoke and the lower iron yoke stop heating, and the residual heat of the auxiliary iron core (1) is used to evaporate all the remaining micro-water; Working condition 2: when the temperature sensor (601) of the detection unit (6) detects that the transformer oil temperature T is less than -30°C, and the upper humidity sensor (602) and the lower humidity sensor (603) both detect that the transformer oil micro-water content is 5 ppm ≤A ≤35 ppm, the control unit (5) turns on the lower controllable switch (4), and the heating winding (3) of the lower iron yoke is connected to the AC power supply (2) to heat the lower part of the transformer oil; until the upper humidity sensor (602) and the lower humidity sensor (603) both detect that the transformer oil micro-water content is A <5 ppm, the control unit (5) turns off the lower controllable switch (4), and the heating winding (3) of the lower iron yoke stops heating, and the residual heat of the auxiliary iron core (1) is used to evaporate all the remaining micro-water; Working condition 3: When the temperature sensor (601) of the detection unit (6) detects that the transformer oil temperature T≧-30°C and the upper humidity sensor (602) detects that the transformer oil micro-water content A>35ppm, the control unit (5) turns on the upper controllable switch (4), and the heating winding (3) of the upper iron yoke is connected to the AC power supply (2) to heat the upper part of the transformer oil; until the upper humidity sensor (602) detects that the transformer oil micro-water content A<5ppm, the control unit (5) turns off the upper controllable switch (4), and the heating winding (3) of the upper iron yoke stops heating, and the residual heat of the auxiliary iron core (1) is used to evaporate all the remaining micro-water.