Converter transformer residual magnetism detection device and detection method based on piezoelectric conversion

Abstract

The invention belongs to the technical field of power equipment, and discloses a converter transformer residual magnetism detection device and detection method based on piezoelectric conversion. The converter transformer residual magnetism detection device comprises a residual magnetism detection sensor and an industrial personal computer. The residual magnetism detection sensor comprises a pressure sensor and a driving piece, the pressure sensor is used for being fixedly connected with an oil tank of the converter transformer, the driving piece is arranged at the pressure acquisition end of the pressure sensor, the driving piece is located on the side, away from an iron core of the converter transformer, of the pressure sensor, and the driving piece is made of ferromagnetic materials; the industrial personal computer is used for obtaining the pressure value output by the pressure sensor and converting the pressure value into the residual magnetism amount of the iron core according to the preset trend relation between the residual magnetism amount and the pressure value. The residual magnetism amount of the iron core is detected based on the residual magnetism detection sensor, the residual magnetism detection precision of the converter transformer is improved, the demagnetization accuracy of the converter transformer is guaranteed, and the safety of a power grid is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power equipment, and in particular relates to a converter transformer residual magnetism detection device and a detection method based on piezoelectric conversion. Background Art

[0002] Ultra-high voltage direct current transmission technology has the characteristics of large capacity, low loss and saving of line corridors, and is an economical and efficient way of transmission. The converter transformer is the core equipment of the ultra-high voltage direct current transmission system, which directly affects the safe and reliable operation of the entire direct current transmission system. The winding DC resistance test is an important item in the routine test of the condition inspection of the converter transformer. It is of great significance to find out the welding quality of the converter transformer winding joints and whether the contact of each joint position of the tap changer is good.

[0003] When testing the DC resistance of the windings of large-capacity converter transformers, the time constant will be large due to the large capacity of the transformer, large winding inductance and small DC resistance, which will lead to a long test time. In recent years, the DC resistance test of converter transformer windings has adopted a large current DC constant current source to increase the DC resistance test speed. This test scheme will cause residual magnetism in the iron core of the converter transformer; for DC systems, when the charged DC pole of the converter transformer is put into operation, the residual magnetism of the iron core will cause faults such as DC pole locking. Therefore, before the converter transformer is put into operation, the residual magnetism in the converter transformer must be eliminated.

[0004] Before eliminating the residual magnetism in the converter transformer, it is necessary to detect the residual magnetism in the converter transformer. Since the converter transformer is a complex combination of stray capacitance and linear / nonlinear inductance, and depending on the external load conditions, there are still complex magnetic processes in the iron core when and after the excitation is removed, resulting in poor reliability of the detection results of the existing residual magnetism detection scheme, which in turn affects the demagnetization effect. Specifically, the existing residual magnetism detection schemes include voltage method, fluxmeter method and indirect measurement method; among them, the voltage method is based on the measured voltage at both ends of the transformer to obtain the residual magnetism of the transformer, which may be affected by stray capacitance and inductance, and the accuracy of the measurement result is poor; the fluxmeter method is to place the fluxmeter on the transformer core and directly measure the magnetic flux in the core. The result is relatively accurate, but the use of the fluxmeter is limited by the field conditions and the operation is complicated, and the feasibility is poor; the indirect measurement method is to indirectly judge the existence and size of residual magnetism by observing the operating characteristics of the transformer (such as excitation inrush current, voltage waveform, etc.), and its accuracy is affected by many factors, such as transformer load conditions, grid voltage fluctuations, etc. Summary of the invention

[0005] The object of the present invention is to provide a converter transformer residual magnetism detection device and detection method based on piezoelectric conversion to solve one or more of the above-mentioned technical problems. In the technical solution provided by the present invention, the residual magnetism of the iron core is detected based on the residual magnetism detection sensor, which improves the accuracy of the converter transformer residual magnetism detection, ensures the accuracy of the converter transformer demagnetization, and improves the safety of the power grid.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a converter transformer residual magnetism detection device based on piezoelectric conversion, comprising: a residual magnetism detection sensor and an industrial computer; wherein, The residual magnetism detection sensor is used to be installed in the oil tank of the converter transformer to be subjected to residual magnetism detection, and the residual magnetism detection sensor is electrically connected to the industrial control machine; The residual magnetism detection sensor comprises a pressure sensor and a drive plate; the pressure sensor is used to be fixedly connected to the oil tank of the converter transformer; the drive plate is arranged at the pressure collection end of the pressure sensor, and the drive plate is located on the side of the pressure sensor away from the iron core of the converter transformer; the drive plate is made of ferromagnetic material; The industrial computer is used to obtain the pressure value output by the pressure sensor, and convert the pressure value into the residual magnetism of the iron core according to the preset trend relationship between the residual magnetism and the pressure value; wherein, the pressure value is generated by the driving plate compressing the pressure sensor under the action of the residual magnetism of the iron core.

[0007] A further improvement of the present invention is that The step of obtaining the trend relationship between the residual magnetism and the pressure value comprises: Prepare a converter transformer core model; Based on the prepared converter transformer core model, different residual magnetism amounts are charged in sequence, and pressure values ​​corresponding to different residual magnetism amounts are obtained through a residual magnetism detection sensor to obtain a trend relationship between the residual magnetism amount and the pressure value.

[0008] A further improvement of the present invention is that The converter transformer core model further includes a protective cover.

[0009] A further improvement of the present invention is that The converter transformer core model comprises: a core body, and a primary winding and a secondary winding respectively wound on the core body; wherein, The primary winding is unloaded; Two ends of the secondary winding are connected to a DC power supply; Two ends of the DC power supply are connected in parallel with a diode, the cathode of the diode is connected to the anode of the DC power supply, and the anode of the diode is connected to the cathode of the DC power supply; A switch is provided between the diode and the DC power supply, and a non-inductive resistor is connected in series between the anode of the diode and the secondary winding.

[0010] A further improvement of the present invention is that The steps of sequentially charging different residual magnetism amounts into the converter transformer core model based on the preparation, and obtaining pressure values ​​corresponding to different residual magnetism amounts through a residual magnetism detection sensor, and obtaining the trend relationship between the residual magnetism amount and the pressure value include: Apply different DC voltages to the converter transformer core model through a DC power supply, disconnect the DC power supply through a switch, generate residual magnetism in the core body, and measure the residual magnetism of the core body using a residual magnetism detection tool; The pressure values ​​corresponding to different residual magnetism quantities are obtained by the residual magnetism detection sensor, and the trend relationship between the residual magnetism quantity and the pressure value is obtained.

[0011] A further improvement of the present invention is that The residual magnetism detection tool is a magnetometer or a Tesla meter.

[0012] A further improvement of the present invention is that Also included: an epoxy resin tube sealed at both ends; The pressure sensor and the driving plate are both packaged in the epoxy resin tube, and the epoxy resin tube is used to be installed on the top of the oil tank of the converter transformer through a flange.

[0013] A further improvement of the present invention is that Also includes: a display module; The display module is used to obtain the residual magnetism output by the industrial computer and display it in digital or graphical form.

[0014] A further improvement of the present invention is that Also includes: an alarm module; The alarm module is used to obtain the residual magnetism output by the industrial computer and compare it with a preset threshold value. When the residual magnetism exceeds the preset threshold value, an alarm signal is automatically issued.

[0015] The present invention provides a converter transformer residual magnetism detection method based on piezoelectric conversion. Based on the converter transformer residual magnetism detection device of the present invention, the converter transformer residual magnetism detection method comprises the following steps: The residual magnetism detection sensor is installed in the oil tank of the converter transformer to be subjected to residual magnetism detection, and the residual magnetism detection sensor is electrically connected to the industrial control machine; Under the action of the residual magnetism of the iron core, the driving plate compresses the pressure sensor, the industrial computer obtains the pressure value output by the pressure sensor, and converts the pressure value into the residual magnetism of the iron core according to the preset trend relationship between the residual magnetism and the pressure value; After the detection is completed, the residual magnetism detection sensor is removed from the oil tank of the converter transformer to be subjected to residual magnetism detection.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The converter transformer residual magnetism detection device disclosed in the present invention detects the residual magnetism of the iron core based on the residual magnetism detection sensor, improves the accuracy of the converter transformer residual magnetism detection, ensures the accuracy of the converter transformer demagnetization, and improves the safety of the power grid. Specifically, the present invention uses piezoelectric conversion technology to convert the tiny displacement or deformation produced by the residual magnetism of the iron core into a measurable pressure value, thereby realizing the indirect measurement of the residual magnetism. This technical means improves the accuracy of the measurement; in addition, the industrial computer converts according to the trend relationship between the preset residual magnetism and the pressure value. This technical means is easy to realize automation and intelligence, thereby improving the detection efficiency. In summary, the converter transformer residual magnetism detection device based on piezoelectric conversion provided by the present invention improves the accuracy and reliability of residual magnetism detection, simplifies the detection process, improves the detection efficiency, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 is a schematic diagram of the installation of a converter transformer residual magnetism detection device based on piezoelectric conversion in an embodiment of the present invention; Figure 2 yes Figure 1 A partial enlarged schematic diagram of the embodiment shown; The explanation of the reference numerals in the figures is as follows: 1. Residual magnetic detection sensor; 11. Pressure sensor; 12. Driving plate; 2. Industrial computer; 3. Fuel tank; 4. Secondary winding; 5. Primary winding. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments and technical solutions are only part of the embodiments of the present invention, not all of the embodiments.

[0020] All other embodiments obtained by those of ordinary skill in the art without creative work based on the technical solutions disclosed in the embodiments of the present invention belong to the scope of protection of the present invention. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device including a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] See also Figure 1 and Figure 2 The embodiment of the present invention provides a converter transformer residual magnetism detection device based on piezoelectric conversion, comprising: a residual magnetism detection sensor 1 and an industrial computer 2; wherein, The residual magnetism detection sensor 1 is used to be installed in the oil tank 3 of the converter transformer to be subjected to residual magnetism detection, and the residual magnetism detection sensor 1 is electrically connected to the industrial computer 2; The residual magnetism detection sensor 1 comprises a pressure sensor 11 and a drive plate 12. The pressure sensor 11 is used to be fixedly connected to the oil tank 3 of the converter transformer; the drive plate 12 is arranged at the pressure collection end of the pressure sensor 11, and the drive plate 12 is located on the side of the pressure sensor 11 away from the iron core of the converter transformer; the drive plate 12 is made of ferromagnetic material; The industrial computer 2 is used to obtain the pressure value output by the pressure sensor 11, and convert the pressure value into the residual magnetism of the iron core according to the preset trend relationship between the residual magnetism and the pressure value; wherein, the pressure value is generated by the drive plate 12 compressing the pressure sensor 11 under the action of the residual magnetism of the iron core; in principle, under the action of the residual magnetism of the iron core, the drive plate 12 made of ferromagnetic material compresses the pressure sensor 11, and the pressure sensor 11 outputs the pressure value generated by the compression.

[0022] The technical solution disclosed in the embodiment of the present invention can improve the accuracy and reliability of residual magnetism detection, simplify the detection process and improve the detection efficiency, have good safety and stability, and have broad application prospects; specifically, the residual magnetism detection sensor of the present invention can be directly installed in the oil tank of the converter transformer, can measure the residual magnetism of the iron core directly and at close range, and avoid the error and interference that may be caused by external measurement; the drive plate is made of ferromagnetic material, which is highly sensitive to the residual magnetism of the iron core. Under the action of residual magnetism, the drive plate will produce a small displacement or deformation, and this change is accurately captured by the pressure sensor, thereby improving the accuracy of measurement. In addition, the residual magnetism detection sensor of the present invention is electrically connected to the industrial control machine, and the industrial control machine can obtain and process the pressure value output by the pressure sensor in real time, and convert it according to the trend relationship between the preset residual magnetism and the pressure value, thereby improving the calculation accuracy and reliability of the residual magnetism; the residual magnetism detection sensor and the industrial control machine are integrated into one, simplifying the detection process, reducing the complexity and operation difficulty of the equipment; because the industrial control machine can obtain and process data in real time, the present invention can realize real-time monitoring of residual magnetism, timely discover and process residual magnetism problems, and improve detection efficiency. Furthermore, the device of the present invention adopts a non-contact measurement method, avoiding the potential safety hazards caused by traditional contact measurement, such as electrical short circuit, equipment damage, etc. The pressure sensor is fixedly connected to the oil tank of the converter transformer, and the drive plate is arranged at the pressure collection end of the pressure sensor. This design can effectively protect the pressure sensor from interference and damage from the external environment, and improve the stability of the equipment. In summary, the device of the present invention can be widely used in residual magnetism detection of converter transformers of various types and specifications, and has wide applicability and versatility; with the development of smart grids and smart operation and maintenance technologies, the real-time residual magnetism data provided by the device of the present invention can provide strong support for the intelligent operation and maintenance of transformers, helping operation and maintenance personnel to understand the equipment status in a timely manner and formulate reasonable operation and maintenance strategies.

[0023] In one embodiment of the present invention, the step of obtaining the trend relationship between the residual magnetism and the pressure value includes: Step S1, preparing a converter transformer core model; Step S2, based on the converter transformer core model prepared in step S1, different residual magnetism amounts are filled in sequence, and the pressure values ​​corresponding to the different residual magnetism amounts are obtained through the residual magnetism detection sensor 1 to obtain the trend relationship between the residual magnetism amount and the pressure value; in the preferred technical solution, a trend graph of different residual magnetism amounts and corresponding pressure values ​​can be drawn to make the trend relationship between the residual magnetism amount and the pressure value clearer.

[0024] In the embodiment of the present invention, in step S1, the prepared converter transformer core model includes: a core body, and a primary winding 5 and a secondary winding 4 respectively wound on the core body; wherein, The primary winding 5 is unloaded, and both ends of the secondary winding 4 are connected to a DC power supply. , DC power supply A diode D is connected in parallel at both ends of the diode, and the cathode of the diode D is connected to the DC power supply The positive electrode of diode D is connected to the DC power supply The cathode of diode D is connected to the DC power supply A switch K is connected between them, and a non-inductive resistor is connected in series between the positive electrode of the diode D and the secondary winding 4. .

[0025] In the embodiment of the present invention, a converter transformer core model is specifically designed so that the experimental conditions are controllable; wherein, the core model includes a core body, a primary winding and a secondary winding, and the primary winding is unloaded, and the secondary winding is connected to a DC power supply. This design makes the experimental conditions more controllable and is convenient for studying the residual magnetism phenomenon under different conditions; a diode is connected in parallel at both ends of the DC power supply, and the current direction of the secondary winding can be easily changed by switch control, thereby simulating different residual magnetism generation and elimination processes. The non-inductive resistor connected in series between the diode and the secondary winding can limit the magnitude of the current. In summary, based on the converter transformer core model provided in the embodiment of the present invention, by changing parameters such as the voltage of the DC power supply and the closing time of the switch, the experimental conditions can be flexibly adjusted to study the influence of different parameters on the residual magnetism.

[0026] In the preferred technical solution of the embodiment of the present invention, the converter transformer core model further includes a protective cover; The protective cover is detachably mounted on the outer side of the core body, and the residual magnetism detection sensor 1 is fixed on the protective cover for easy experimental installation.

[0027] In one embodiment of the present invention, in step S2, based on the converter transformer core model prepared in step S1, different residual magnetism amounts are sequentially charged, and pressure values ​​corresponding to different residual magnetism amounts are obtained by a residual magnetism detection sensor, and the step of obtaining the trend relationship between the residual magnetism amount and the pressure value specifically includes: Through DC power supply Apply different DC voltages to the converter transformer core model , through the switch K to the DC power supply Open the gate to generate residual magnetism in the core body, and use the residual magnetism detection tool to measure the residual magnetism of the core body; In a further optional technical solution, the residual magnetism detection tool includes a magnetometer or a Tesla meter.

[0028] In the preferred technical solution of the embodiment of the present invention, the precise control of the residual magnetism and the efficient collection of data can be achieved; wherein, by applying different DC voltages to the converter transformer core model through a DC power supply, the magnetization intensity in the core can be precisely controlled, and then the magnitude of the residual magnetism can be controlled. This precise control provides a basis for establishing an accurate trend relationship between the residual magnetism and the pressure value; by using a switch to disconnect the DC power supply, the current can be quickly cut off, so that the magnetic field in the core can be rapidly decayed to the residual magnetism state, avoiding the heat accumulation and magnetic saturation problems that may be caused by long-term power-on. Professional residual magnetism detection tools such as magnetometers or Tesla meters can be used to directly and accurately measure the residual magnetism of the core body. These tools have the characteristics of high precision and fast response, which greatly improves the efficiency and accuracy of data collection. In summary, based on the above steps, the pressure values ​​corresponding to different residual magnetism can be obtained through multiple experiments, and then a trend graph of the residual magnetism and the pressure value can be drawn to obtain the trend relationship between the residual magnetism and the pressure value.

[0029] Specifically and exemplarily, an embodiment of the present invention provides a converter transformer residual magnetism detection device based on piezoelectric conversion, comprising: a residual magnetism detection sensor 1 and an industrial computer 2; wherein the residual magnetism detection sensor 1 is installed in the oil tank 3 of the converter transformer, and the residual magnetism detection sensor 1 comprises a pressure sensor 11 and a drive sheet 12, and the drive sheet 12 is made of ferromagnetic material, specifically a 1 mm thick steel sheet; the pressure sensor 11 and the drive sheet 12 are both encapsulated in an epoxy resin tube sealed at both ends, and the epoxy resin tube is installed on the top of the oil tank 3 through a flange. The pressure sensor 11 is attached to the bottom of the epoxy resin tube, and the drive sheet 12 is attached to the top of the pressure sensor 11; the pressure sensor 11 is electrically connected to the industrial computer 2 through a signal line; when there is residual magnetism in the iron core, the residual magnetism will generate a magnetic attraction on the drive sheet 12, so that the drive sheet 12 presses the pressure sensor 11, and the greater the residual magnetism, the greater the corresponding pressure, and by calculating the corresponding relationship between the residual magnetism and the pressure value, the pressure value can be converted into the residual magnetism of the iron core through the industrial computer 2.

[0030] In one embodiment of the present invention, a detection method using the converter transformer residual magnetism detection device based on piezoelectric conversion according to the embodiment of the present invention comprises the following steps: Step S1, preparing a converter transformer core model, including: the converter transformer core model includes a core body, and the core body has the same size as the actual converter transformer core; a protective cover is detachably installed on the outer side of the core body to avoid electric shock accidents during excitation, and a residual magnetism detection sensor 1 is fixed on the protective cover; wherein the detachable protective cover structure can be easily removed so as to directly perform residual magnetism detection on the core body after the excitation is completed.

[0031] The core body is respectively wound with a primary winding 5 and a secondary winding 4, which are the same as the actual converter transformer windings; the primary winding 5 is unloaded, and the two ends of the secondary winding 4 are connected to a DC power supply. , DC power supply A diode D is connected in parallel at both ends of the diode, and the cathode of the diode D is connected to the DC power supply The positive electrode of diode D is connected to the DC power supply The cathode of diode D is connected to the DC power supply A switch K is connected between them, and a non-inductive resistor is connected in series between the positive electrode of the diode D and the secondary winding 4. .

[0032] Step S2, sequentially charging different residual magnetism amounts into the converter transformer core, specifically includes: Step S21, through a DC power supply Apply different DC voltages to the converter transformer core model , at this time, the non-inductive resistor The excitation voltage is generated on ; Step S22, the DC power supply is switched on by switch K. To open the gate, the excitation voltage Rapid reverse, the excitation current is freewheeling through the diode D, part of the magnetic field energy is converted into heat energy through the resistor, and part of it generates residual magnetism in the core body; Step S23, using a residual magnetism detection tool such as a magnetometer or a Tesla meter to measure the residual magnetism of the core body; Among them, diode D is used for freewheeling. When the core body is excited, diode D is reversely cut off and does not consume power; when discharging, the internal resistance of diode D is approximately zero, which improves the accuracy of magnetization.

[0033] Step S3, using the residual magnetism detection sensor 1 to obtain the pressure values ​​corresponding to different residual magnetism amounts; the position of the residual magnetism detection sensor 1 from the iron core is consistent with the installation position of the actual converter transformer residual magnetism detection sensor 1.

[0034] Step S4, drawing a trend graph of different residual magnetism and pressure values ​​according to the residual magnetism of the core body measured in step S2 and the pressure value measured by the residual magnetism detection sensor 1 measured in step S3; Step S5, measuring the pressure value of the residual magnetism detection sensor 1 on the actual converter transformer, and calculating the residual magnetism of the converter transformer according to the trend diagram obtained in step S4.

[0035] The residual magnetism detection sensor 1 should be removed after completing the converter transformer test to avoid affecting the magnetic field distribution inside the converter transformer and threatening the safe operation of the converter transformer.

[0036] In the technical solution provided by the embodiment of the present invention, a high-precision and high-stability pressure sensor is selected to ensure that it can accurately measure the tiny pressure changes generated by the drive plate. The pressure sensor can be detachably fixedly connected to the oil tank of the converter transformer by bolts or other means to ensure its stability and reliability during the measurement process and the convenience of removal after measurement; the drive plate is made of high-quality ferromagnetic materials, such as silicon steel sheets or Permalloy, to ensure its high sensitivity to the residual magnetism of the iron core. The industrial computer uses a high-performance and high-reliability industrial computer with powerful data processing and communication capabilities. The industrial computer is electrically connected to the residual magnetism detection sensor through a cable or wirelessly to obtain the pressure value output by the pressure sensor in real time. The industrial computer has a preset trend relationship algorithm between the residual magnetism and the pressure value, which can automatically convert the residual magnetism of the iron core according to the obtained pressure value.

[0037] When the technical solution provided by the embodiment of the present invention is used, first, the residual magnetism detection sensor is installed in the oil tank of the converter transformer to be residual magnetism detected, and the pressure sensor is fixedly connected to the oil tank firmly and reliably; then, the industrial computer is electrically connected to the residual magnetism detection sensor, and necessary debugging and calibration are performed to ensure the normal operation and measurement accuracy of the device. The industrial computer obtains the pressure value output by the pressure sensor, and the data processing algorithm built into the industrial computer performs preprocessing and filtering operations on the obtained pressure value to eliminate the influence of noise and interference signals; then, according to the preset trend relationship algorithm of the residual magnetism and the pressure value, the processed pressure value is converted into the residual magnetism of the iron core. The industrial computer displays the converted residual magnetism in the form of numbers or graphics on the screen for real-time viewing by the operation and maintenance personnel; at the same time, the industrial computer is also provided with an alarm function. When the residual magnetism exceeds the preset threshold, an alarm signal will be automatically issued to remind the operation and maintenance personnel to take timely measures for processing.

[0038] In summary, the embodiment of the present invention discloses a residual magnetism detection device and detection method for a converter transformer based on piezoelectric conversion. The residual magnetism detection device for a converter transformer includes a residual magnetism detection sensor and an industrial control computer. The residual magnetism detection sensor is electrically connected to the industrial control computer. The residual magnetism detection sensor is installed in the oil tank of the converter transformer. The residual magnetism detection sensor includes a pressure sensor and a drive sheet. The pressure sensor is fixedly connected to the oil tank of the converter transformer. The drive sheet is made of ferromagnetic material. The drive sheet is installed on the side of the pressure sensor away from the iron core of the converter transformer. The residual magnetism detection sensor detects the pressure value of the residual magnetism of the iron core on the drive sheet, and the industrial control computer converts the pressure value into the residual magnetism of the iron core. In the technical solution of the embodiment of the present invention, by installing the residual magnetism detection sensor in the oil tank of the converter transformer, the pressure sensor detects the suction force of the residual magnetism on the adsorption sheet, thereby judging the residual magnetism of the iron core, improving the accuracy of residual magnetism detection, ensuring the accuracy of demagnetization of the converter transformer, and improving the safety of the power grid.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A converter transformer residual magnetism detection device based on piezoelectric conversion, characterized in that: include: A residual magnetism detection sensor (1) and an industrial computer (2); wherein: The residual magnetism detection sensor (1) is used to be installed in the oil tank (3) of the converter transformer to be subjected to residual magnetism detection, and the residual magnetism detection sensor (1) is electrically connected to the industrial control computer (2); The residual magnetism detection sensor (1) comprises a pressure sensor (11) and a drive plate (12); the pressure sensor (11) is used to be fixedly connected to the oil tank (3) of the converter transformer; the drive plate (12) is arranged at the pressure collection end of the pressure sensor (11), and the drive plate (12) is located on a side of the pressure sensor (11) away from the iron core of the converter transformer; the drive plate (12) is made of ferromagnetic material; The industrial computer (2) is used to obtain the pressure value output by the pressure sensor (11), and convert the pressure value into the residual magnetism of the iron core according to a preset trend relationship between the residual magnetism and the pressure value; wherein the pressure value is generated when the driving plate (12) compresses the pressure sensor (11) under the action of the residual magnetism of the iron core.

2. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 1 is characterized in that: The step of obtaining the trend relationship between the residual magnetism and the pressure value comprises: Prepare a converter transformer core model; Based on the prepared converter transformer core model, different residual magnetism quantities are charged in sequence, and pressure values ​​corresponding to different residual magnetism quantities are obtained through a residual magnetism detection sensor (1), thereby obtaining a trend relationship between the residual magnetism quantity and the pressure value.

3. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 2 is characterized in that: The converter transformer core model also includes a protective cover.

4. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 2 is characterized in that: The converter transformer core model comprises: a core body, and a primary winding (5) and a secondary winding (4) respectively wound on the core body; wherein: The primary winding (5) is unloaded; Two ends of the secondary winding (4) are connected to a DC power supply; Two ends of the DC power supply are connected in parallel with a diode, the cathode of the diode is connected to the anode of the DC power supply, and the anode of the diode is connected to the cathode of the DC power supply; A switch is provided between the diode and the DC power supply, and a non-inductive resistor is connected in series between the positive electrode of the diode and the secondary winding (4).

5. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 4 is characterized in that: The step of sequentially charging different residual magnetism amounts into the converter transformer core model prepared based on the converter transformer core model and obtaining pressure values ​​corresponding to different residual magnetism amounts through a residual magnetism detection sensor (1) to obtain the trend relationship between the residual magnetism amount and the pressure value comprises: Apply different DC voltages to the converter transformer core model through a DC power supply, disconnect the DC power supply through a switch, generate residual magnetism in the core body, and measure the residual magnetism of the core body using a residual magnetism detection tool; The pressure values ​​corresponding to different residual magnetism quantities are obtained by using a residual magnetism detection sensor (1), and the trend relationship between the residual magnetism quantity and the pressure value is obtained.

6. A converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 5, characterized in that: The residual magnetism detection tool is a magnetometer or a Tesla meter.

7. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 1 is characterized in that: Also included: an epoxy resin tube sealed at both ends; The pressure sensor (11) and the drive plate (12) are both encapsulated in the epoxy resin tube, and the epoxy resin tube is used to be installed on the top of the oil tank (3) of the converter transformer through a flange.

8. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 1 is characterized in that: Also includes: a display module; The display module is used to obtain the residual magnetism output by the industrial computer (2) and display it in digital or graphical form.

9. The converter transformer residual magnetism detection device based on piezoelectric conversion according to claim 1 is characterized in that: Also includes: an alarm module; The alarm module is used to obtain the residual magnetism output by the industrial computer (2) and compare it with a preset threshold value, and automatically send out an alarm signal when the residual magnetism exceeds the preset threshold value.

10. A converter transformer residual magnetism detection method based on piezoelectric conversion, characterized in that: Based on the converter transformer residual magnetism detection device according to claim 1, the converter transformer residual magnetism detection method comprises the following steps: The residual magnetism detection sensor (1) is installed in the oil tank (3) of the converter transformer to be subjected to residual magnetism detection, and the residual magnetism detection sensor (1) is electrically connected to the industrial control computer (2); Under the action of the residual magnetism of the iron core, the driving plate (12) compresses the pressure sensor (11), the industrial computer (2) obtains the pressure value output by the pressure sensor (11), and converts the pressure value into the residual magnetism of the iron core according to a preset trend relationship between the residual magnetism and the pressure value; After the detection is completed, the residual magnetism detection sensor (1) is removed from the oil tank (3) of the converter transformer to be subjected to residual magnetism detection.

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