Voltage and current integrated intelligent sensing device and method based on insulator

Abstract

The invention discloses an insulator-based voltage and current integrated intelligent sensing device and method.The insulator-based voltage and current integrated intelligent sensing device comprises a voltage sensing unit, a current sensing unit and an insulation fixing box, firstly, line voltage and current are detected on the basis that the insulation performance and mechanical strength of an insulator are kept sufficient; then, the voltage sensing unit realizes uniformization of an induced electric field, determination of a transfer function and relative minimization of partial discharge, and the voltage sensing unit is implanted into the insulator, so that the insulation performance of the voltage sensing unit is good; and finally, the current sensing unit improves the magnetic field measurement sensitivity by utilizing the magnetic gathering capability of the open type magnetic ring air gap and the optimization design of the magnetic ring structure parameters, and enhances the magnetic interference resistance by utilizing the optimization design of the magnetic ring structure parameters and the magnetic ring series.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to an insulator-based voltage and current integrated intelligent sensor device and method. Background Art

[0002] In the power system, the voltage and current measurement of distribution lines has a significant impact on the application fields of energy metering, relay protection, overvoltage online monitoring and intelligent device control. Traditional monitoring methods usually rely on separate current sensors and voltage sensors, but this method has problems such as large number of equipment, complex installation, large space occupation, new safety hazards and increased energy consumption.

[0003] For voltage measurement, the non-contact voltage measurement method based on the electric field coupling principle abstracts the equivalent coupling capacitance by treating the measured line, the sensor sensing electrode and the earth as capacitor plates, and uses the capacitor voltage division principle to perform attenuation measurement of the measured line voltage. It has the advantages of low insulation difficulty, simple structure, convenient loading and unloading, and high construction safety. However, the uncertainty of the primary coupling capacitance of this method leads to the uncertainty of the input-output transfer relationship between the sensor output voltage and the measured line voltage value, and the structural shape and parameters of each electrode affect the size of the induced electric field, the uniformity of the electric field, the coupling capacitance value and the transfer function. Therefore, it is very necessary to optimize the design of the structural shape and parameters of each electrode to achieve the relatively optimal sensing characteristic target.

[0004] For current measurement, TMR sensor chips, as a new type of magnetoresistive sensor, are expected to become the consistent, highly sensitive, and low-power intelligent current sensing technology required for digital power grids. However, as a magnetic inversion measurement technology, the high sensitivity of TMR sensor chips in transmission line applications also makes them susceptible to complex environments such as stray magnetic fields, thereby reducing measurement accuracy. Although the high magnetic permeability magnetic ring air gap can achieve the aggregation and amplification of the magnetic field generated by the target current and has a certain effect of shielding interference magnetic fields, the magnetic field aggregation and anti-interference capabilities of the single magnetic ring structure need to be further improved. Therefore, it is also necessary to optimize the magnetic ring series and structural parameters to improve the anti-interference ability and magnetic sensitivity.

[0005] With the increasing demand for intelligent equipment under the construction of smart grids, the primary equipment is integrated with intelligent units of secondary equipment, which greatly improves the intelligent operation level and reliability of primary and secondary equipment. It is necessary to develop an integrated sensing device that can monitor current and voltage at the same time with high precision, high stability and high reliability. An integrated intelligent sensing device and method of voltage and current based on insulators is produced in accordance with this technological development trend. The integration of primary and secondary equipment will bring problems in insulation, partial discharge and mechanical strength. Therefore, it is more urgent to further optimize the design of various structural shapes and parameters of the secondary equipment sensing unit under the constraints of the primary equipment. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a research and development of an insulator-based integrated voltage and current intelligent sensing device and method, which can not only solve the problems existing in the separate configuration of traditional sensors, but also help us further study the optimization of the structural shape and parameters of each sensing unit after the fusion of primary and secondary equipment, and can also expand the application space and engineering value of the non-contact voltage measurement method based on the electric field coupling principle and the TMR current sensor with an open multi-stage magnetic ring structure in integrated measurement, thereby meeting the high requirements of the smart grid for power system status monitoring, optimized scheduling and fault identification.

[0007] The present invention is implemented by the following technical solution: an insulator-based voltage and current integrated intelligent sensor device, comprising:

[0008] A voltage sensing unit, which is embedded in the insulator and includes a high-voltage electrode, a sensing electrode, a grounding shielding ring, a grading ring and an insulating isolation material, and is used to measure the voltage of the transmission line;

[0009] A current sensing unit, including a multi-stage magnetic ring and a TMR sensor chip, is used to measure the current of the transmission line;

[0010] The insulating fixing box is an open-and-close structure used for insulating and protecting the current sensing unit and fixing the multi-level magnetic ring and the TMR sensor chip. The interior of the box is integrated with the insulator through supporting bolts.

[0011] The voltage sensing unit has a bottom end of a high-voltage electrode that is optimized to be a semi-ellipsoid to reduce the maximum electric field strength and to homogenize the electric field; an integrated grading ring without isolation is present at the top of the grounding shielding ring to homogenize the electric field; a fixed grounding insert at the lower end of the grounding shielding ring is also integrally formed during casting to effectively ground and fix the grounding shielding ring to achieve casting and installation; grading rings are separately provided at both upper and lower ends of the sensing electrode, and insulating isolation material is included between the sensing electrode and its grading ring; insulating isolation material is also included between the sensing electrode and the grounding shielding ring; each structural shape parameter is designed, fixed, and the position in the insulator is determined before being integrally cast with the insulator.

[0012] The front-end magnetic field measurement performance of the current sensing unit is closely related to the number of stages and structural dimensions of the multi-stage magnetic ring. After optimized design, the TMR sensor chip is placed in the air gap of the inner-stage magnetic ring, which can obtain higher magnetic field measurement sensitivity; the design of the multi-stage magnetic ring structure can significantly enhance the anti-magnetic interference capability and the magnetic field uniformity of the sensing position, so as to improve the robustness of the TMR sensor chip in on-site deployment.

[0013] The insulating fixing box is placed on the upper end of the insulator. The internal part of the opening and closing structure of the box houses and fixes the positions of the multi-stage magnetic ring, the TMR sensor chip and the supporting bolts, ensuring that the chip is placed at a specific optimized position in the air gap of the inner magnetic ring. The transmission line or its connecting conductor is passed through the middle of the magnetic ring in a through-hole manner to form an electrical connection with the supporting bolts.

[0014] The voltage-grading ring and the grounding shielding ring are coaxial circular rings with a radius of 1 mm and cast integrally with the grounding shielding ring. The two isolated voltage-grading rings of the sensing electrode are cylindrical with the same radius, thickness and axis as the sensing electrode.

[0015] The insulating isolation material is located in the gap between the sensing electrode and the equalizing rings at its upper and lower ends, and between the sensing electrode and the grounding shielding ring. Its function is to perform insulation isolation so that there is no electrical connection, and to integrate and fix the relative positions of the two to facilitate pouring and prevent bubbles from being generated during pouring.

[0016] The multi-stage magnetic ring is an integrated magnetic ring formed by coaxial magnetic rings optimized into three stages, and is composed of alternating high magnetic permeability and high conductivity media. The inner magnetic ring of the first layer of high magnetic permeability medium mainly gathers the annular dispersed magnetic field generated by the target current at the center inside the magnetic ring, the second layer of magnetic ring is a high conductivity medium material, and the third layer of magnetic ring is a high magnetic permeability medium again. The second and third layers of magnetic rings improve the anti-magnetic interference performance.

[0017] The support bolt has a lower end stud that passes through the center hole at the lower end of the insulating fixing box and is connected to the threaded hole of the high-voltage electrode. The upper end is used to connect and support the transmission line and also to fix the insulating fixing box, thereby connecting the two sensor units to form an integrated device.

[0018] The present invention also provides a voltage and current integrated intelligent sensing method based on an insulator, which is performed through the following operations:

[0019] After the transmission line is fixed on the supporting bolts in the insulating fixing box and electrically connected to the supporting bolts, the transmission line passes through the center of the magnetic ring, and the high-voltage electrode and the transmission line form an equipotential, so that the voltage of the transmission line is measured using the voltage sensing unit of the integrated intelligent sensing device, and the current of the transmission line is measured using its current sensing unit.

[0020] The method for measuring the voltage of the transmission line aims at homogenizing the electric field, reducing the electric field strength, increasing the voltage division ratio and the measurement accuracy, and optimizes the design of all structural shapes and parameters of the voltage sensing unit in the insulator, including the high-voltage electrode, the induction electrode, the grounding shielding ring, the grading ring and the insulating isolation material, so as to form a certain primary and secondary coupling capacitance and a homogenized induced electric field, thereby utilizing the capacitance voltage division principle to linearly and accurately convert the voltage of the transmission line into a low-voltage signal for collection, and then invert the voltage of the transmission line.

[0021] The principle of capacitive voltage division is that the high voltage electrode and the induction electrode form a primary coupling capacitor C iw , the induction electrode and the grounded shielding ring form a secondary coupling capacitor C ig After the structural parameters are determined, the two capacitors are determined by a precision LCR meter, and the sensing electrode is measured by a sampling resistor R m and C ig Connected to the grounded shielding ring, when the sensor works in the self-integration characteristic mode, the transmission line voltage is divided by the primary and secondary coupling capacitors in series to obtain: Among them, V o (s) is the transmission line input voltage, V i (s) is the output voltage of the sensor unit.

[0022] The method for measuring the current of the transmission line is to design a TMR current sensor with an open multi-stage magnetic ring structure that has strong anti-magnetic interference ability and high magnetic field measurement sensitivity. The TMR sensor chip is placed at the center of the air gap of the inner magnetic ring. After the size structure of the first layer of inner magnetic ring is optimized and determined, the magnetic field amplification factor at the measuring point of the TMR sensor chip is determined. When the relative position of the transmission line and the TMR sensor chip remains unchanged, according to the Biot-Savart law, when the current of the transmission line changes, the surrounding magnetic field changes accordingly, and the internal magnetic resistance of the TMR sensor chip also changes accordingly, that is, the change in the magnetic field can be converted into a corresponding electrical signal output by the TMR sensor chip. Therefore, the current inside the conductor can be indirectly inverted according to the output voltage of the TMR sensor chip, thereby achieving the purpose of measuring the current of the transmission line.

[0023] Beneficial effects of the present invention: The present invention proposes an intelligent voltage and current integrated sensing device and method based on insulators, which realizes the integration of primary and secondary equipment and the simultaneous detection of the voltage and current of the transmission line. First, it can simultaneously detect the line voltage and current on the basis of maintaining the insulation performance and mechanical strength performance of the insulator; then, under the system optimization method of integrating the voltage sensing unit into the various structural shapes and parameters inside the insulator, the voltage sensing unit realizes the homogenization of the induced electric field, the determination of the transfer function and the relative minimization of the local discharge, and because it is implanted inside the insulator, the voltage sensing unit has good insulation performance; finally, the current sensing unit improves the magnetic field measurement sensitivity by utilizing the magnetic gathering ability of the open magnetic ring air gap and the optimized design of the magnetic ring structural parameters, and also enhances the anti-magnetic interference ability by utilizing the optimized design of the magnetic ring structural parameters and the magnetic ring series. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation of this patent or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of this patent. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0025] Figure 1 A schematic diagram of the structure of a voltage sensing unit in an insulator-based voltage-current integrated intelligent sensing device provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the measurement principle of the cross-sectional structure of a voltage sensing unit in an insulator-based voltage-current integrated intelligent sensing device provided in an embodiment of the present invention;

[0027] Figure 3 A schematic structural diagram of a support bolt, an insulating fixing box and a current sensing unit in an insulator-based voltage-current integrated intelligent sensing device provided in an embodiment of the present invention;

[0028] Figure 4 A perspective view of the opening and closing structure of a support bolt, an insulating fixing box and a current sensing unit in an insulator-based voltage and current integrated intelligent sensing device provided in an embodiment of the present invention

[0029] Figure 5 A measurement principle diagram of a current sensing unit in an insulator-based voltage-current integrated intelligent sensing device provided in an embodiment of the present invention;

[0030] Figure 6 An overall structural system diagram of an insulator-based integrated voltage and current intelligent sensing device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings to clearly, understandably and completely describe the purpose, technical solutions and advantages of this patent. Obviously, the described embodiments are part of the embodiments of this patent, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0032] like Figure 1 As shown, an insulator-based voltage and current integrated intelligent sensing device comprises:

[0033] The voltage sensing unit is embedded in the insulator 1, and comprises a high-voltage electrode 2, an induction electrode 3, a grounding shielding ring 4, a grading ring 5 and an insulating isolation material 6, and is used to measure the voltage of the transmission line; the high-voltage electrode 2 is electrically connected to the transmission line 9 through the upper threaded hole 7 to form an equipotential; the grounding shielding ring 4 is connected to the real earth through the lower threaded hole 8 and the installation environment (such as the stud on the crossarm); the induction electrode 3 senses the electrical signal and leads it out through the lead, and the sensor outputs the electrical signal, which is the voltage difference formed between the induction electrode 3 and the grounding shielding ring 4; and the design of the grading ring 5, the insulating isolation material 6 and the parameter values ​​in the device is ensured, all of which are to improve the internal insulation performance, sensing stability and accuracy of the insulator 1.

[0034] like Figure 2 As shown, the high voltage electrode 2 and the induction electrode 3 form a primary coupling capacitor C iw , the induction electrode 3 and the ground shielding ring 4 form a secondary coupling capacitor C ig After the structural parameters are determined, the two capacitance values ​​can also be determined by a precision LCR meter, R m is the sampling resistor, and the sensing electrode 3 is connected through R m and C ig Connected to the ground shield ring 4. When the sensor operates in the self-integration characteristic mode, the high voltage electrode 2 has an input voltage V electrically connected to the transmission line 9. i (s), so the voltage is divided by the primary and secondary coupling capacitors in series: Where V o (s) is the output voltage of the sensor unit.

[0035] The current sensing unit includes a multi-stage magnetic ring 11 and a TMR sensing chip 12, and is used to measure the current of the transmission line;

[0036] The insulating fixing box 10 is an open-and-close structure, used for insulating and protecting the current sensing unit and fixing the multi-level magnetic ring 11 and the TMR sensor chip 12, and its interior is integrated with the insulator 1 through supporting bolts.

[0037] like Figure 3 and 4 As shown, the insulating fixing box 10 forms an open-and-closed structure through a hinge 14, in which the positions of the multi-stage magnetic ring 11 and the TMR sensor chip 12 are fixed, and the TMR sensor chip 12 is placed at the center of the air gap of the first inner magnetic ring. The power transmission line 9 passes through the wire holes left in the center of the multi-stage magnetic ring 11 and the insulating fixing box 10; the upper end of the support bolt 13 is used to electrically connect and support the power transmission line 9, and overlaps with the insulating fixing box 10 so that the insulating fixing box 10 is fixed by the lower end stud.

[0038] like Figure 5 As shown, according to the Biot-Savart law, a spiral magnetic field is generated around the conductor. When the current in the transmission line 9 changes, the surrounding magnetic field changes accordingly, and the internal magnetic resistance of the TMR sensor chip 12 also changes accordingly. The change in the magnetic field can be converted into a corresponding electrical signal output. Therefore, when the relative position of the transmission line 9 and the TMR sensor chip 12 is kept unchanged, the current inside the transmission line 9 can be indirectly reflected based on the output voltage of the TMR sensor chip 12, thereby achieving the purpose of current measurement.

[0039] like Figure 6 As shown, the lower end stud of the support bolt 13 passes through the central hole at the lower end of the insulating fixing box 10 and is connected to the threaded hole 7 of the high-voltage electrode 2, thereby forming an integrated voltage and current intelligent sensing device based on the insulator 1. It can simultaneously detect the voltage and current of the transmission line 9 while maintaining sufficient insulation performance and mechanical strength of the insulator 1. In addition, it can also monitor various application scenarios such as induced lightning overvoltage, overcurrent and line faults.

Claims

1. An insulator-based integrated voltage and current intelligent sensor device, characterized in that: include, A voltage sensing unit, which is embedded in the insulator and includes a high-voltage electrode, a sensing electrode, a grounding shielding ring, a grading ring and an insulating isolation material, and is used to measure the voltage of the transmission line; A current sensing unit, including a multi-stage magnetic ring and a TMR sensor chip, is used to measure the current of the transmission line; The insulating fixing box is an open-and-close structure used for insulating and protecting the current sensing unit and fixing the multi-level magnetic ring and the TMR sensor chip. The interior of the box is integrated with the insulator through supporting bolts.

2. The voltage and current integrated intelligent sensor device based on insulator according to claim 1 is characterized in that: The voltage sensing unit has a bottom end of a high-voltage electrode in the shape of a semi-ellipsoid; an integrated grading ring without isolation is present at the top of the grounding shielding ring, and a fixed grounding insert at the lower end of the grounding shielding ring is also integrally formed during casting; grading rings are separately provided at both upper and lower ends of the sensing electrode, and insulating isolation material is included between the sensing electrode and its grading ring; insulating isolation material is included between the sensing electrode and the grounding shielding ring; and each structural shape parameter is designed, fixed, and the position in the insulator is determined before being integrally cast with the insulator.

3. The voltage and current integrated intelligent sensor device based on insulator according to claim 1 is characterized in that: The current sensing unit and the TMR sensing chip are placed in the air gap of the inner magnetic ring.

4. The voltage and current integrated intelligent sensor device based on insulator according to claim 1 is characterized in that: The insulating fixing box is placed on the upper end of the insulator. The internal part of the opening and closing structure of the box is used to place and fix the positions of the multi-stage magnetic ring, the TMR sensor chip and the supporting bolts. The transmission line or its connecting conductor is passed through the middle of the magnetic ring in a through-hole manner to form an electrical connection with the supporting bolts.

5. The voltage and current integrated intelligent sensor device based on insulator according to claim 2, characterized in that: The voltage-grading ring and the grounding shielding ring are coaxial circular rings with a radius of 1 mm and cast integrally with the grounding shielding ring. The two isolated voltage-grading rings of the sensing electrode are cylindrical with the same radius, thickness and axis as the sensing electrode.

6. The voltage and current integrated intelligent sensor device based on insulator according to claim 2, characterized in that: The insulating isolation material is located in the gap between the sensing electrode and the equalizing rings at the upper and lower ends thereof, and between the sensing electrode and the grounding shielding ring.

7. The voltage and current integrated intelligent sensor device based on insulator according to claim 3 is characterized in that: The multi-stage magnetic ring is an integrated magnetic ring formed by three-stage coaxial magnetic rings, which are composed of alternating high magnetic permeability and high conductivity media. The inner magnetic ring of the first layer of high magnetic permeability medium gathers the annular dispersed magnetic field generated by the target current at the center inside the magnetic ring, the second layer of magnetic ring is a high conductivity medium material, and the third layer of magnetic ring is a high magnetic permeability medium.

8. The voltage and current integrated intelligent sensor device based on insulator according to claim 4 is characterized in that: The support bolt has a lower end stud that passes through the center hole at the lower end of the insulating fixing box and is connected to the threaded hole of the high-voltage electrode. The upper end is used to connect and support the transmission line and also to fix the insulating fixing box, thereby connecting the two sensor units to form an integrated device.

9. An insulator-based integrated voltage and current intelligent sensing method, using the device described in any one of claims 1 to 8, characterized in that: After the following operations: After the transmission line is fixed on the support bolts in the insulating fixing box and electrically connected to the support bolts, the transmission line passes through the center of the magnetic ring, and the high-voltage electrode and the transmission line form an equipotential, so that the voltage of the transmission line is measured by the voltage sensing unit of the integrated intelligent sensing device, and the current of the transmission line is measured by the current sensing unit; Measure the voltage of the transmission line, form a certain primary and secondary coupling capacitance and a uniform induced electric field, and then use the principle of capacitive voltage division to linearly and accurately convert the voltage of the transmission line into a low-voltage signal for collection, and then invert the voltage of the transmission line; The principle of capacitive voltage division is that the high voltage electrode and the induction electrode form a primary coupling capacitor C iw , the induction electrode and the grounded shielding ring form a secondary coupling capacitor C ig After the structural parameters are determined, the two capacitors are determined by a precision LCR meter, and the sensing electrode is measured by a sampling resistor R m and C ig Connected to the grounded shielding ring, when the sensor works in the self-integration characteristic mode, the transmission line voltage is divided by the primary and secondary coupling capacitors in series to obtain: Among them, V o (s) is the transmission line input voltage, V i (s) is the output voltage of the sensor unit; To measure the current in the transmission line, the TMR sensor chip is placed at the center of the air gap of the inner magnetic ring. After the size structure of the first layer of inner magnetic ring is optimized, the magnetic field amplification factor at the measuring point of the TMR sensor chip is determined. When the relative position of the transmission line and the TMR sensor chip remains unchanged, according to the Biot-Savart law, when the current in the transmission line changes, the surrounding magnetic field changes accordingly, and the internal magnetic resistance of the TMR sensor chip also changes accordingly, that is, the change in the magnetic field can be converted into a corresponding electrical signal output by the TMR sensor chip.

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