Integrated measuring device for high-voltage reactor based on electromagnetic coupling

Abstract

The invention discloses an integrated measuring device for a high-voltage reactor based on electromagnetic coupling, which comprises a high-voltage wiring terminal (1) used for accessing a high-voltage signal of a measured device, and the high-voltage wiring terminal (1) is connected with a high-voltage reactor coil (3) through a signal line. The high-voltage reactor coil (3) is also connected with a voltage regulation control box (11) for controlling voltage boosting and voltage reducing of the high-voltage reactor coil through a high-voltage signal input socket (7); the device further comprises a low-voltage voltage-dividing coil (4), the low-voltage voltage-dividing coil (4) is connected with a gear regulator (5) used for regulating impedance of the low-voltage voltage-dividing coil, the low-voltage voltage-dividing coil (4) is further connected with a measurement signal output socket (8) through a signal line, and the measurement signal output socket (8) is connected with a measurement device box (10) through a signal line. The device is simple in structure, stable and reliable in insulation performance and convenient to use.

Description

Technical Field

[0001] The invention relates to the field of AC withstand voltage test of power transmission and transformation equipment in power systems, and in particular to an integrated measuring device for high-voltage reactors based on electromagnetic coupling. Background Art

[0002] With the continuous increase in the scale of urban power grids, the renovation projects of the original power transmission and transformation equipment have also increased. Ensuring the reliability of new power equipment has become an important research topic in the power system. Among them, the AC withstand voltage test is the most direct and effective method to discover dangerous concentrated defects of electrical equipment and assess the insulation strength of equipment. Therefore, the number of AC withstand voltage tests in power systems has increased in recent years. In order to ensure that the voltage value applied during the AC withstand voltage test meets the requirements of the regulations, an AC high-voltage measurement system must be used at the operation site to monitor the test voltage.

[0003] The existing AC withstand voltage test measurement system is mainly composed of a variable frequency power supply, an excitation transformer, a reactor, and a voltage divider. The reactor and the voltage divider are large in size and weight, and are not easy to carry and move. Limited by factors such as on-site space and the capacity of the equipment under test, the voltage divider needs to be used in series in multiple sections in actual use. During the construction of the measurement system, it needs to be carried in sections many times and rewired. This pressure measurement method results in low test efficiency and high time cost. Actual on-site operations need to improve the convenience of on-site instruments as much as possible, reduce the workload of test personnel, and improve on-site work efficiency while ensuring on-site safety. Summary of the invention

[0004] Based on the electromagnetic coupling principle, the present invention integrates a voltage divider and a reactor into one, and designs an integrated AC high-voltage measurement system with simple structure, reliable insulation and convenient use to meet the needs of AC withstand voltage test.

[0005] In order to achieve the above-mentioned object, the present invention provides an integrated measuring device for a high-voltage reactor based on electromagnetic coupling, which comprises: a high-voltage terminal 1 for accessing a high-voltage signal of a device under test, the high-voltage terminal 1 being connected to a high-voltage reactor coil 3 through a signal line, the high-voltage reactor coil 3 being further connected to a voltage regulating control box 11 for controlling the voltage increase and decrease of the high-voltage reactor coil through a high-voltage signal input socket 7;

[0006] The integrated measuring device also includes: a low-voltage voltage dividing coil 4, which is connected to a gear regulator 5 for adjusting the impedance of the low-voltage voltage dividing coil. The low-voltage voltage dividing coil 4 is also connected to a measurement signal output socket 8 via a signal line, and the measurement signal output socket 8 is connected to a measuring device box 10 via a signal line.

[0007] In a preferred manner, a grading ring 2 and an insulating shielding layer 6 for balancing the electric field distribution are installed on the side of the integrated measuring device.

[0008] In a preferred manner, a device base 9 for supporting and protecting is installed at the bottom of the integrated measuring device.

[0009] In a preferred manner, the high-voltage reactor coil magnetic field optimization model for reducing electromagnetic interference is:

[0010]

[0011] Where B is the magnetic induction intensity, μ is the relative magnetic permeability, and σ is the electrical conductivity.

[0012] In a preferred manner, the circuit of the measuring device box 10 includes: an STM32 main control chip for calculating real-time current and voltage, the STM32 main control chip is connected to the CC2541 / NRF24L01 chip for wireless communication through the RXD port and the TXD serial port, the STM32 main control chip is connected to the DHT11 / SHT21 chip for measuring temperature and humidity through the temperature and humidity IO pin, the STM32 main control chip is connected to the ILI9341 chip for displaying data through the display SPI / IO pin, and the STM32 main control chip is connected to the L293D / A4988 chip for controlling the high-voltage reactor coil voltage through the key IO pin.

[0013] The beneficial effects of the present invention are as follows: wide applicability, and can be widely used in AC withstand voltage tests of 66kV and 500kV power equipment; simple structure, easy use, and can be quickly built and installed during on-site operations, reducing operation time and workload; the parameter measurement ratio is adjustable, reducing the need to purchase similar measurement systems with different parameter specifications; reliable insulation performance, able to ensure stable operation in a high-voltage environment, reducing the risk of accidents, and ensuring the safety of operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the device system of the present invention;

[0015] Figure 2 It is the circuit principle diagram of the present invention;

[0016] Figure 3 A circuit diagram of the present invention;

[0017] Figure 4 It is a schematic diagram of the structure of the measuring device of the present invention;

[0018] Figure 5 Calculate a line graph for the magnetic field distribution of the present invention;

[0019] Figure 6It is a magnetic field distribution calculation effect diagram of the present invention;

[0020] Figure 7 It is the electrical principle diagram of the measurement circuit of the present invention.

[0021] Figure 4 In: 1. High-voltage terminal; 2. Equalizing ring; 3. High-voltage reactor coil; 4. Low-voltage dividing coil; 5. Shift adjuster; 6. Insulation shielding layer; 7. High-voltage signal input socket; 8. Measurement signal output socket; 9. Device base; 10. Measurement device box; 11. Voltage regulating control box. DETAILED DESCRIPTION Specific embodiment:

[0023] like Figure 1 As shown, the present invention is connected to the AC withstand voltage equipment in the AC withstand voltage system, the measuring device is connected in series with the low-voltage voltage dividing coil, the measuring system and the control system acquire commands and transmit data through wireless signals, the control system sends the real-time parameters to the control instrument after calculation, and the staff checks the data and sends commands at the control instrument. In the AC withstand voltage test, this method can accurately measure the AC high voltage value, significantly reduce the workload of on-site operators, and at the same time improve the convenience of using instruments and meters, reduce the later maintenance costs, and provide solid support for the quality improvement and efficiency optimization of the power grid system.

[0024] like Figure 2 , 3 As shown, the measurement system circuit is composed of a wireless communication module, a control unit, a temperature and humidity test module, a button and a display module, which can complete electrical isolation, on-site temperature and humidity testing, setting parameters such as voltage divider ratio, and displaying the function of measuring data. The wireless communication module uses CC2541 or NRF24L01 chip, which is connected to the main control chip STM32 through pins, and receives the measurement device signal through wireless communication; the temperature and humidity test module uses DHT11 / SHT21, which is connected to the main control chip STM32 through IO pins, and then connected to the display screen of the control instrument through the ILI9341 chip, and the temperature and humidity, voltage and current parameters and other data processed by the main control unit are sent to the display screen, so that the staff can view the data in real time; the button module is connected to the control motor through the L293D or A4988 chip, and the motor is operated after receiving the instruction.

[0025] like Figure 4As shown, the integrated measuring device for high-voltage reactor of the present invention is composed of a low-voltage voltage dividing coil 4, a high-voltage reactor 3 and a measuring device 10, and the low-voltage voltage dividing coil 4 and the high-voltage reactor 3 have the same axis; the voltage regulating control box 11 is connected to the high-voltage reactor 3, and the boost voltage value of the high-voltage reactor is controlled through a signal line; the low-voltage voltage dividing coil 4 is connected to the measurement signal output socket 8, and the signal line is output to the measuring device box 10, and the measurement parameters are read in real time through the measuring device box 10; the low-voltage voltage dividing coil adopts a variable reactance design, and different gears are selected by adjusting the gear adjuster 5, and the number of turns inside the coil is changed to obtain different reactance values, thereby realizing the function of adjustable voltage dividing ratio; the grading ring 2 and the insulating shielding layer 6 play a role in balancing the electric field distribution and reducing electromagnetic interference; the device base 9 is grounded to play a supporting and protective role.

[0026] like Figure 5 , 6 As shown, the changes in the internal current parameters of the high-voltage coil and the low-voltage coil and the electromagnetic distribution of the measuring device under different coil parameters can be obtained by calculation. To ensure the safe and stable operation of the device, the internal current parameters of the coil cannot be greater than the rated current of the system. To ensure the measurement accuracy, the magnetic field strength of the device should satisfy the linear change of the low-voltage coil magnetic field with the high-voltage coil magnetic field. The optimal device parameters can be obtained by calculation. The specific values ​​vary according to the changes in the equipment parameters. The present invention only provides a calculation method.

[0027] like Figure 7 As shown, C1 and C2 are filter capacitors, R is the filter resistor, and R L is the load resistance, U L is the load voltage, U e It is the output voltage of the low voltage divider coil.

[0028] Using the device of the present invention, an integrated measurement method for a reactor includes the following steps:

[0029] S1: Design the structure of integrated measurement device for high voltage reactor of AC withstand voltage system;

[0030] S2: Build an electromagnetic field model of the integrated measurement device to optimize electromagnetic distribution and reduce electromagnetic interference;

[0031] S3: Design a voltage measurement circuit based on the model obtained in S1 and S2.

[0032] In S1, the integrated measuring device for high-voltage reactors is composed of a low-voltage voltage-dividing coil, a high-voltage reactor and a measuring device. The low-voltage voltage-dividing coil has the same axis as the high-voltage reactor, and converts the high-voltage electrical signal into a low-voltage electrical signal through electromagnetic coupling and outputs it to the measuring device; the low-voltage voltage-dividing coil adopts a variable reactance design, and by selecting different gears and changing the number of turns inside the coil to obtain different reactance values, thereby realizing the function of adjustable voltage-dividing ratio; the relative displacement of the low-voltage voltage-dividing coil and the high-voltage reactor in the axial direction is adjustable, and considering that there may be electromagnetic interference in the field environment, the optimal relative displacement can be obtained through simulation calculation to reduce its interference to the measuring device and ensure the measurement accuracy; the measuring device is connected in series with the low-voltage voltage-dividing coil, and is composed of a measuring circuit, an analog-to-digital conversion unit, a control unit, a button and a display unit, which can complete electrical isolation, set parameters such as voltage-dividing ratio and field temperature, and display the measurement data.

[0033] In S2, when establishing the electromagnetic field model of the integrated measuring device, the sinusoidal current acting on the high-voltage reactor will generate a sinusoidal alternating magnetic field, which will cause a changing induced current to be generated in the low-voltage divider coil. The electric field generated by the induced current will react on the magnetic field of the high-voltage reactor, affecting the distribution of the overall magnetic field of the device. Considering that the change of the conduction current in the coil does not directly affect the distribution of the magnetic field, only the influence of eddy current and displacement current on the distribution of the overall magnetic field of the device is discussed.

[0034] Assume that the eddy current and displacement current in the low voltage divider coil are:

[0035]

[0036] When the high-voltage reactor is an air-core reactor, since there is no conductor, the eddy current is zero, and then:

[0037]

[0038] When there is an iron core inside the high-voltage reactor, since the eddy current is much larger than the displacement current, there is:

[0039]

[0040] It can be concluded that the electromagnetic field distribution of the integrated measuring device for high-voltage reactors is affected by the coil core, the number of coil turns, the coil turn spacing, the wire diameter, and the relative positions of the high and low voltage coils.

[0041] Supplementary constitutive equations and their Maxwell form equations:

[0042] D=εE (5)

[0043] B=μH (6)

[0044] J=σE (7)

[0045]

[0046] Among them, D is the electric flux density, E is the electric field strength, ε is the dielectric constant, B is the magnetic induction intensity, H is the magnetic field intensity, μ is the relative magnetic permeability, J is the eddy current density, and σ is the electrical conductivity.

[0047] It can be seen that the influence of external current frequency, amplitude and phase angle affects the current density distribution inside the coil, and then affects the electromagnetic field distribution of the integrated measurement device for high-voltage reactors.

[0048] Performing curl operations on both sides of equation 1-8, we have:

[0049]

[0050] Apply the vector identity to the left side of the above equation We can get:

[0051]

[0052] Considering that the current in the AC withstand voltage system changes sinusoidally, the angular frequency of the alternating current is taken as ω. Combined with the above formula, the magnetic field model of the high-voltage reactor can be written as:

[0053]

[0054] According to the above formula, the magnetic field distribution under different excitation currents and device structures can be calculated, and the structural parameters can be obtained to reduce the interference of the electromagnetic field on the measuring device and ensure the measurement accuracy.

[0055] In S3, the measuring circuit is connected in series with the low-voltage voltage divider coil, and is composed of an RCπ-type filter circuit, a load resistor, an ammeter and a voltmeter. For the DC component, the output voltage on the voltmeter side is:

[0056]

[0057] For the AC component, the output voltage on the voltmeter side is:

[0058]

[0059] Pick Then we have:

[0060]

[0061] In the above formula, C1 and C2 are filter capacitors, R is the filter resistor, and R L is the load resistance, U L is the load voltage, U eis the output voltage of the low voltage divider coil. According to the above formula, the real-time current and voltage data can be calculated to realize the real-time data acquisition function.

[0062] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An integrated measuring device for high-voltage reactor based on electromagnetic coupling, characterized in that: It includes: A high-voltage connection terminal (1) for receiving a high-voltage signal of a device under test, wherein the high-voltage connection terminal (1) is connected to a high-voltage reactor coil (3) via a signal line, and the high-voltage reactor coil (3) is also connected to a voltage regulating control box (11) for controlling the voltage increase or decrease of the high-voltage reactor coil via a high-voltage signal input socket (7); The integrated measuring device further comprises: a low-voltage voltage dividing coil (4), the low-voltage voltage dividing coil (4) being connected to a gear position regulator (5) for adjusting the impedance of the low-voltage voltage dividing coil, the low-voltage voltage dividing coil (4) being also connected to a measuring signal output socket (8) via a signal line, and the measuring signal output socket (8) being connected to a measuring device box (10) via a signal line.

2. The integrated measuring device for high-voltage reactor based on electromagnetic coupling according to claim 1, characterized in that: A grading ring (2) and an insulating shielding layer (6) for balancing the electric field distribution are installed on the side of the integrated measuring device.

3. The integrated measuring device for high-voltage reactor based on electromagnetic coupling according to claim 1, characterized in that: A device base (9) for supporting and protecting is installed at the bottom of the integrated measuring device.

4. The integrated measuring device for high-voltage reactor based on electromagnetic coupling according to claim 1, characterized in that: The magnetic field optimization model of the high-voltage reactor coil used to reduce electromagnetic interference is: Where B is the magnetic induction intensity, μ is the relative magnetic permeability, and σ is the electrical conductivity.

5. The integrated measuring device for high-voltage reactor based on electromagnetic coupling according to claim 1, characterized in that: The circuit of the measuring device box (10) comprises: an STM32 main control chip for calculating real-time current and voltage, the STM32 main control chip being connected to a CC2541 / NRF24L01 chip for wireless communication via an RXD port and a TXD serial port, the STM32 main control chip being connected to a DHT11 / SHT21 chip for measuring temperature and humidity via a temperature and humidity IO pin, the STM32 main control chip being connected to an ILI9341 chip for displaying data via a display screen SPI / IO pin, and the STM32 main control chip being connected to an L293D / A4988 chip for controlling the coil voltage of a high-voltage reactor via a key IO pin.

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