Core type transformer magnetizing and demagnetizing device
Through the combined design of the main control board, power supply board and interactive module, the automatic magnetization and demagnetization of power transformers are realized, which solves the problems of complex operation and current limitation in the existing technology, outputs a stable constant current, reduces inrush current and supports communication.
Patent Information
- Application Number
- CN202423307798.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing technologies cannot achieve automated magnetization and demagnetization of power transformers. Furthermore, the magnetization and demagnetization process is limited by current and internal resistance, which cannot effectively reduce inrush current. The operation is complex and cannot communicate with external devices.
It adopts a combined design of main control board, power board, power module and interaction module. It realizes automatic control through current sampling and voltage sampling circuit, outputs stable constant current, and performs sinusoidal current demagnetization through commutation circuit. It supports three independent magnetization and demagnetization channels and has communication function.
It realizes automated magnetization and demagnetization of power transformers, outputs stable high voltage and constant current, adapts to high internal resistance conditions, reduces inrush current, simplifies operation, and supports communication with external devices.
Smart Images
Figure CN223941615U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to transformer technical field especially relates to a core type transformer magnetizing and demagnetizing device. BACKGROUND
[0002] The transformer in the primary equipment of power system is nonlinear load, needs to pre-magnetize and demagnetize power transformer, after the demagnetization of power transformer, magnetizes again, after the pre-magnetization of power transformer, when closing, can reduce the excitation inrush current and its impact on power grid. Because power transformer is electrified for the first time or is electrified again after long time without use, a large amount of magnetic force is needed to penetrate the iron core in this process. And the continuous excitation inrush current can be several times to several ten times of the rated current, can cause high voltage switch tripping, voltage fluctuation of circuit, and even affect the operation of whole power grid. When power transformer is put into, the phase angle of system voltage and the residual flux of transformer core when putting into are intervened. If the magnetization of transformer can be carried out, the magnetic flux of each phase can be known, and then the phase angle of system voltage and the magnetic flux of transformer core are consistent when putting into, so that the excitation inrush current can be reduced to the minimum.
[0003] The prior art generally has two independent technologies, one is demagnetization, the residual flux of transformer is zero after the demagnetization of power transformer, but the magnetic flux of three phases is the same, and only one way can guarantee no large excitation inrush current when closing, and the other two ways cannot be guaranteed. One is magnetization, the magnetization of power transformer can be carried out, but the original residual flux cannot be offset, only large magnetic flux can be charged, and the magnetic flux cannot be reduced. The current of magnetization also cannot reach a large current, and is limited by current. The two technologies mentioned above are independent devices, and it is difficult to realize automatic demagnetization and magnetization, the charging and discharging process needs to replace the instrument, the charging and discharging current is limited, and the charging and discharging of power transformers requiring large current cannot be carried out. The charging and discharging process cannot realize automation, and cannot communicate with external devices, so that the operation process is complicated. For the case that the internal resistance of power transformer is large, high-voltage constant-current charging and discharging cannot be realized, and the internal resistance of power transformer is limited. SUMMARY
[0004] The utility model provides a core type transformer magnetizing and demagnetizing device, and aims at solving the problem that the prior art cannot automatically realize magnetization and demagnetization.
[0005] The utility model provides a core type transformer magnetization and degaussing device, including main control board, a plurality of power board, power module and interactive module, a plurality of power board all with main control board connects, power module is connected with main control board and power board respectively, interactive module with main control board connects, power board is equipped with control chip, voltage reduction circuit, commutation circuit, current sampling circuit and voltage sampling circuit, control chip with main control board connects, main control board exports PWM signal to voltage reduction circuit, voltage reduction circuit's output and commutation circuit's input connection, commutation circuit is connected with each phase of transformer, commutation circuit is connected with current sampling circuit and voltage sampling circuit respectively, current sampling circuit and voltage sampling circuit are connected with control chip respectively.
[0006] As a further improvement of the utility model, the current sampling circuit collects the current value and inputs the control chip, and the control chip compares the current value with the current value set in the main control board. If it is too small, the PWM signal with high duty ratio is output to the voltage reduction circuit.
[0007] As a further improvement of the utility model, the current sampling circuit collects the current value and inputs the control chip, and the control chip compares the current value with the current value set in the main control board. If it is too large, the PWM signal with low duty ratio is output to the voltage reduction circuit.
[0008] As a further improvement of the utility model, when degaussing, the commutation circuit outputs a sinusoidal current, and the amplitude of the sinusoidal wave in each cycle first increases from small to large, and then decreases from large to small.
[0009] As a further improvement of the utility model, the interactive module includes a touch screen, data parameters are set through the touch screen, and the touch screen transmits data to the main control board through a serial port.
[0010] As a further improvement of the utility model, the interactive module includes a printer, and the printer is connected to the main control board.
[0011] As a further improvement of the utility model, the main control board is built-in with a memory for storing data parameters.
[0012] The utility model has the advantages of realizing automatic degaussing and magnetization, outputting stable and constant current, outputting higher voltage constant current to cope with the case that the internal resistance of the power transformer is high, realizing various communications, and independently outputting three-way degaussing and magnetization. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 is the connection schematic diagram of each component of the utility model;
[0014] Figure 2 This is a schematic diagram of the connections of the components in the power board of this utility model. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.
[0016] This utility model provides a core-type transformer magnetization and demagnetization device, including a main control board, several power boards, a power module, and an interaction module. The power boards are all connected to the main control board. The power modules are connected to both the main control board and the power boards. The interaction module is connected to the main control board. Each power board includes a control chip, a step-down circuit, a commutation circuit, a current sampling circuit, and a voltage sampling circuit. The control chip is connected to the main control board. The main control board outputs a PWM signal to the step-down circuit. The output of the step-down circuit is connected to the input of the commutation circuit. The commutation circuit is connected to each phase of the transformer. The commutation circuit is connected to both the current sampling circuit and the voltage sampling circuit. The current sampling circuit and the voltage sampling circuit are connected to the control chip.
[0017] In one embodiment of this utility model, the current sampling circuit collects the current value and inputs it into the control chip. The control chip compares the current value with the current value set in the main control board. If the current value is smaller, it outputs a PWM signal with a high duty cycle to the step-down circuit.
[0018] In another embodiment of this utility model, the current sampling circuit collects the current value and inputs it into the control chip. The control chip compares the current value with the current value set in the main control board. If the current value is larger, it outputs a PWM signal with a low duty cycle to the step-down circuit.
[0019] In another embodiment of this utility model, during demagnetization, the commutation circuit outputs a sinusoidal current, with one cycle from positive to negative. The amplitude of the sinusoidal wave in each cycle first increases from small to large, and then decreases from large to small.
[0020] In another embodiment of this utility model, the interaction module includes a touch screen, through which data parameters are set, and the touch screen transmits data to the main control board via a serial port.
[0021] In another embodiment of this utility model, the interactive module includes a printer, which is connected to the main control board.
[0022] In another embodiment of this utility model, the main control board has a built-in memory for storing data parameters.
[0023] This invention provides a core-type transformer magnetization and demagnetization device, achieving automated magnetization and demagnetization, stable constant current output, and the ability to output high voltage constant current. It addresses situations where the internal resistance of the power transformer is high, enables various communication functions, and ensures communication with switching devices. It can independently output three channels for demagnetization and magnetization, and each channel can simultaneously magnetize different types of magnets. The output current is sufficiently stable, and the detected current can reach 1mA. It also has a discharge function when high voltage is detected.
[0024] This device is a combination of a power module, a main control board, a power supply board, a touch screen, and a printer.
[0025] The power module converts AC power into DC power, providing DC voltage, primarily for stepping down the high DC voltage output to the power board. The main control board performs data calculations, exchanges data with the power board, and interacts with the touchscreen. It stores and parses data. The main control board and the voltage board communicate via independent serial ports. The touchscreen and the main control board also communicate via serial port. The power board outputs a constant current; the output voltage changes with the load to achieve constant current output. The main control board and the voltage board communicate via independent serial ports; in this embodiment, three power boards are provided. The touchscreen enables human-machine interaction, allowing users to set functions and data parameters. The set parameters are then saved to the main control board's memory via the serial port. The printer prints data and keeps paper for archiving. Communication between the power board and the main control board primarily uses Ethernet, CAN, serial, or RS-485 communication. The main control board is responsible for calculating and processing data to control the output current value.
[0026] The power module outputs power to the power board and main control board via power cables. The serial communication interfaces of the main control board and power board are isolated serial communication circuits, connected externally via communication cables. The serial communication interfaces of the main control board and touchscreen are also isolated serial communication circuits, connected externally via communication cables. The serial communication interfaces of the main control board and printer are RS-232 serial communication circuits, connected externally via communication cables.
[0027] The power board achieves constant current output as follows: The control chip obtains the current value through the current sampling circuit and compares it with the set current value. If the current value is lower, it outputs a PWM signal with a high duty cycle, increasing the output voltage and thus increasing the current. Conversely, if the current value sampled by the control chip is higher than the set current value, it outputs a PWM signal with a low duty cycle, decreasing the output voltage and thus decreasing the current. This continuous change in output voltage maintains a constant output current. Dynamic adjustments are made during magnetization based on these changes in output voltage and current. Finally, the adjusted values are output to each phase of the transformer via the commutation circuit. Each phase of the transformer is individually connected to the commutation circuit, allowing for individual control and adjustment of each phase. During demagnetization, the commutation circuit operates, enabling reverse current flow. The output sinusoidal current cycles from positive to negative, with the amplitude of the sinusoidal wave increasing and then decreasing in each cycle, thus achieving demagnetization. A step-down circuit reduces the high-voltage current supplied by the power module to prevent damage to downstream equipment.
[0028] Before the power transformer is energized, the circuit breaker is in the open position, and the transformer is not connected to the power grid. Once the transformer voltage drops to zero, connect this device to the primary terminals of the ABC three-phase circuit via cables. This device enables automatic demagnetization and magnetization; the magnetization current for each phase can be set differently for independent demagnetization and magnetization. After demagnetization and magnetization are complete, data can be printed via a printer. It also allows data exchange with external devices via Ethernet.
[0029] This device enables the demagnetization and remagnetization of power transformers, ensuring that the residual magnetic flux of each phase differs from the design value. Therefore, during closing, the voltage phases of the three phases correspond to the residual magnetic flux, making the bias magnetism and residual magnetism polarities opposite, minimizing inrush current and preventing grid fluctuations. The residual magnetism polarity also differs by 120° between each of the three phases. Furthermore, during three-phase linkage closing, the initial phase angles of the three phases also differ by 120°, and the bias magnetism polarities also differ by 120°. This naturally cancels out the bias magnetism and residual magnetism in the three-phase magnetic circuit of the transformer.
[0030] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.
Claims
1. A core-type transformer magnetization and demagnetization device, characterized in that, The system includes a main control board, several power boards, power modules, and an interaction module. Each power board is connected to the main control board. Each power module is connected to both the main control board and the power boards. The interaction module is also connected to the main control board. Each power board includes a control chip, a step-down circuit, a commutation circuit, a current sampling circuit, and a voltage sampling circuit. The control chip is connected to the main control board. The main control board outputs a PWM signal to the step-down circuit. The output of the step-down circuit is connected to the input of the commutation circuit. The commutation circuit is connected to each phase of the transformer. The commutation circuit is connected to both the current sampling circuit and the voltage sampling circuit. Both the current sampling circuit and the voltage sampling circuit are connected to the control chip.
2. The core-type transformer magnetization and demagnetization device according to claim 1, characterized in that, The current sampling circuit collects the current value and inputs it into the control chip. The control chip compares the current value with the current value set in the main control board. If the current value is smaller, it outputs a PWM signal with a high duty cycle to the buck circuit.
3. The core-type transformer magnetization and demagnetization device according to claim 1, characterized in that, The current sampling circuit collects the current value and inputs it into the control chip. The control chip compares the current value with the current value set in the main control board. If the current value is larger, it outputs a PWM signal with a low duty cycle to the buck circuit.
4. The core-type transformer magnetization and demagnetization device according to claim 1, characterized in that, During demagnetization, the commutation circuit outputs a sinusoidal current, with one cycle from positive to negative. The amplitude of the sinusoidal wave in each cycle first increases from small to large, and then decreases from large to small.
5. The core-type transformer magnetization and demagnetization device according to claim 4, characterized in that, The interaction module includes a touch screen, through which data parameters are set, and the touch screen transmits data to the main control board via a serial port.
6. The core-type transformer magnetization and demagnetization device according to claim 1, characterized in that, The interaction module includes a printer, which is connected to the main control board.
7. The core-type transformer magnetization and demagnetization device according to claim 6, characterized in that, The main control board has a built-in memory for storing data parameters.