Non-contact micro intelligent sensing optimization method and system for potential of secondary direct-current circuit

Abstract

The present invention relates to the technical field of potential measurement. Disclosed are a non-contact micro intelligent sensing optimization method and system for the potential of a secondary direct-current circuit. The method comprises: performing demodulation on a weak alternating-current modulation signal by means of a demodulation circuit, amplifying the weak alternating-current modulation signal to output a stable and amplified measurable voltage signal, and performing noise processing on the voltage signal to obtain a stable direct-current voltage signal; inputting the direct-current voltage signal into a comprehensive calculation module for analytic processing; using micro sensors to perform measurement to obtain information, inputting the information into the comprehensive calculation module to analyze and correct a potential measurement result, and outputting the measurement result to a communication module to output same outwards; and packaging devices to form potential collection "probes" and a potential measurement "unit", wherein the potential measurement "unit" supports the connection of a plurality of potential collection "probes". The present invention eliminates the mechanical friction that is present in a conventional driving structure, such that under long-time operation, the power consumption is lower than that of other driving modes, the stability is higher, and the operation and maintenance costs are also reduced.

Description

Non-contact micro-intelligent sensing optimization method and system for secondary DC circuit potential Technical Field

[0001] The present invention relates to the technical field of potential measurement, and in particular to a non-contact micro-intelligent sensing optimization method and system for secondary DC circuit potential. Background Art

[0002] The secondary system within a power system station monitors, controls, regulates, and protects the operating conditions of primary equipment. The secondary DC circuit is a crucial component of the secondary system, serving as an information "bridge" connecting primary and secondary equipment. It transmits signals and commands for monitoring, controlling, regulating, and protecting secondary equipment. When defects such as a loose connection, broken wires, or misconnections occur in the secondary DC circuit, the corresponding signals and commands cannot be correctly and reliably transmitted, leading to malfunction or failure of secondary equipment and circuit breakers, such as measurement and control, relay protection, and safety automatic devices, causing serious damage to primary equipment and even serious consequences such as personal injury and large-scale power outages. The potential of each node in the secondary DC circuit, as a direct representation of the circuit's operating status, is the fundamental basis for monitoring the circuit's operating status and handling faults and defects. Measuring the potential of the secondary DC circuit is essential for early warning, analysis, and handling of defects such as loose connections, broken wires, and misconnections in the secondary DC circuit. Currently, the secondary DC circuit potential is primarily measured using a multimeter. This method requires good electrical contact between the measuring element (test leads) and the measured location. This method is prone to DC short circuits, ground faults, and electric shocks caused by incorrect meter settings, accidental contact, and parasitic circuits. Furthermore, it is inconvenient to conduct real-time monitoring. Therefore, non-contact secondary circuit DC potential measurement is an effective solution.

[0003] With the construction and application of HVDC transmission projects, the research and engineering practice of non-contact DC potential measurement technology has gradually attracted attention. Currently, there are three main methods for non-contact DC potential measurement: the first is the impulse current method (also known as the probe method). This method uses the impulse current generated by the instantaneous insertion of a measuring probe into a strong DC electric field to obtain the electric field strength. In 2002, researchers Harland CJ et al. published a paper in the journal Applied Physics Letters describing the specific measurement method. However, this method is susceptible to electrostatic interference, resulting in unstable error and has been rarely used in engineering practice. The second is the photoelectric effect method. This method uses the changes in the light transmission properties of special crystal materials in different electric fields to measure electric field strength. Common examples include the Pockels effect and the magneto-optical Kerr effect. A typical example is the research results published by researchers Cecelja F et al. in the journal Measurement in 2007. This method requires expensive materials and is susceptible to external temperature and vibration interference, resulting in poor long-term stability and reliability. The application and reports of these two methods primarily occurred in the early days of HVDC transmission and are now rarely used. The third is the variable capacitance method. This method uses a special processing method to generate dynamically changing capacitance in a static DC electric field. By measuring the changing capacitance or the current generated by the capacitance change, the DC electric field strength is measured, and the DC potential is then measured. Common methods for generating changing capacitance include field-grinding sensors, field-controlled effect sensors using varactor diodes, and inverse piezoelectric effect sensors using piezoelectric devices. This method can achieve high-sensitivity measurements, has a smaller sensor size, is more robust against interference, and is more economical, showing great application prospects.

[0004] Patent application number 202310430039.6 discloses a method for measuring transmission line voltage using a MEMS voltage sensor. This method uses a comb-tooth drive structure to drive the shielding electrode to vibrate laterally, changing the projected area with the sensing electrode, causing the surface charge of the sensing electrode to change and generate an induced current, thereby achieving electrostatic measurement. However, the comb-tooth drive structure used in this method is prone to wear and tear, making it difficult to meet the requirements of long-term continuous use (more than 12 years). The shielding area is changed to obtain variable capacitance, and the measurement accuracy is lower than expected under weak field conditions. The use of stainless steel boxes to encapsulate measurement, processing, and communication components will cause the sensor to be too heavy and too large. At the same time, the simple use of packaging to solve problems such as dust and humidity can only solve the problem of sensitive chips being affected by the environment. Some electric fields are still exposed to the environment and may lead to poor heat dissipation performance.

[0005] Patent application number 202210425080.X discloses a non-contact measurement device and method for the DC voltage of an electric wire. This method realizes non-contact measurement of the DC voltage of an electric wire based on the inverse piezoelectric effect of a piezoelectric device. It is hoped that by eliminating the mechanical vibration structure of the measuring component, the power consumption of the component can be reduced, the volume can be reduced, and the accuracy can be improved. However, the volume and accuracy of the equipment are not clearly described.

[0006] The above method does not deeply consider the issues of anti-interference in complex electromagnetic environments, miniaturization, lightweight, and accurate measurement of weak electric fields. In high-voltage primary measurement scenarios, when the requirements for the above performance are not high, it has certain usage prospects, but it is difficult to apply to secondary DC circuit potential measurement scenarios.

[0007] Research on non-contact intelligent measurement technology suitable for secondary DC circuit potential has just emerged. Patent application number 202211136966.9 discloses a hard pressure plate non-contact DC electric field measurement method and device. This method uses the change of the barrier capacitance of the varactor diode as a feature to measure the surface electric field of the secondary circuit lead. It can more accurately measure the terminal potential of the protection panel cabinet pressure plate, and solve the problem of identifying the status of the protection panel cabinet pressure plate based on the measured potential. It has strong engineering guidance value for measuring the secondary DC circuit potential.

[0008] However, secondary DC circuits are widely distributed (e.g., within protection panels, terminal boxes, and control cabinets), with some located within protective chambers and others in outdoor high-voltage switchgear fields. These environments are complex and subject to harsh operating conditions. Measurement devices typically require narrow installation spaces, are subject to severe AC / DC electromagnetic field coupling, and experience significant temperature, humidity, and air pressure fluctuations. Engineering applications also require measurement devices to possess high measurement accuracy and long-term stable operation. Therefore, the following issues need to be addressed:

[0009] (1) High measurement accuracy.

[0010] (2) Miniaturization and lightweight.

[0011] (3) Have strong anti-electromagnetic interference capability.

[0012] (4) Have a wide spectrum of adaptability to temperature, humidity, and air pressure. Generally, the indoor operating environment is good, and the temperature, humidity, and air pressure will not fluctuate widely (such as when measuring the potential of the secondary DC circuit inside the protection panel cabinet). However, the temperature, humidity, and air pressure inside the terminal box and the control cabinet in the outdoor switch field vary greatly. The above climate parameters will significantly affect the relative dielectric constant of the air, and thus affect the capacitance measurement. Therefore, the measuring components are required to have a wide spectrum of adaptability to temperature, humidity, and air pressure.

[0013] It should be able to meet the requirements of long-term stable operation. The measuring components collect the secondary circuit potential in real time to achieve real-time monitoring of the secondary circuit status. It should have the ability to operate stably for a long time to avoid the high failure rate that increases the equipment operation and maintenance workload.

[0014] Summary of the Invention

[0015] In view of the above existing problems, the present invention is proposed.

[0016] Therefore, the present invention provides a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential, which can solve the problem of weak electric field strength of the measured object and difficulty in high-precision measurement in traditional technologies.

[0017] To solve the above technical problems, the present invention provides the following technical solutions: a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential, comprising:

[0018] The weak AC current modulation signal is demodulated by a demodulation circuit, and the weak AC current modulation signal is amplified by a three-op-amp differential amplifier to output a stable, amplified, measurable voltage signal. The voltage signal is passed through a phase-sensitive detector to eliminate noise signals of non-driving frequencies, and the voltage signal after noise elimination is filtered out by a low-pass filter to obtain a stable DC voltage signal; the DC voltage signal is input into a comprehensive operation module for analysis and processing to obtain the potential of the measured object; micro temperature, humidity and air pressure sensors are used to measure the ambient temperature, humidity and air pressure information, and input into the comprehensive operation module for analysis and correction of the measured potential results, and the measurement results are output to the communication module for external output, supporting both analog and digital output modes; the sensing plate, micro Lorentz force driver, three-op-amp differential amplifier, phase-sensitive detector, and low-pass filter are packaged to form a potential acquisition "probe", and the comprehensive operation module, micro temperature, humidity and air pressure sensors, and communication module are packaged to form a potential measurement "unit", which supports the connection of multiple potential acquisition "probes".

[0019] As a preferred solution of the non-contact micro-intelligent sensing optimization method for the secondary DC circuit potential described in the present invention, the demodulation of the weak AC current modulation signal includes installing an intelligent sensor on the secondary DC circuit to be measured. Based on the vibration capacitor modulation principle, the capacitance between the sensing plate and the charged body to be measured generates an alternating capacitance under the drive of a Lorentz force driver, causing periodic changes in the charge on the sensing plate, and collecting the AC current signal i(t) on the sensing plate.

[0020] The AC current signal is converted into an amplified AC potential signal through a three-op-amp differential amplifier to obtain the AC potential signal u0(t).

[0021] After the AC potential signal passes through phase-sensitive detection and low-pass filter data processing, the real-time potential signal u0 of the secondary DC circuit to be tested is output.

[0022] By correcting the relative dielectric constant of air that affects capacitance measurement, the influence of temperature, humidity and air pressure on the measurement signal is resolved, and the corrected DC signal u1 is obtained.

[0023] According to the output potential u1 of the smart sensor in the potential measurement scenario, the actual output potential of the smart sensor is calibrated in combination with the fitting formula u2=ku1. The output potential of the measuring unit of the smart sensor after potential calibration is the secondary DC circuit potential to be measured.

[0024] As a preferred embodiment of the non-contact micro-intelligent sensing optimization method for the secondary DC circuit potential of the present invention, the three-op-amp differential amplifier amplifies the output, and a back-end electrical signal detection circuit amplifies the electrical signal based on the vibration capacitance modulation principle to generate a potential signal output. The distance between the sensing plate and the secondary DC circuit to be measured is: d = d0 + Δd sin (ωt)

[0025] Where d0 is the distance between the vibrating plate and the secondary DC circuit to be measured when the vibrating plate is in equilibrium, Δd is the vibration amplitude of the inductive plate. Once the driving structure based on the Lorentz force is selected, d0 and Δd can be obtained by measurement. ω is the angular frequency of vibration, ω = 2πf, f is the frequency of the AC current passed through the vibrating cantilever beam of the driving structure, and t is time.

[0026] Then the capacitance on the vibrating plate is:

[0027] Among them, ε is the dielectric constant of air, and S is the area of ​​the vibrating plate.

[0028] Then the induced current on the sensing plate is:

[0029] Where U is the potential difference between the sensing plate and the surface of the secondary DC circuit to be measured.

[0030] As a preferred solution of the non-contact micro-intelligent sensing optimization method for secondary DC circuit potential described in the present invention, the demodulation includes that the AC current signal output by the vibration capacitance modulation circuit needs to be converted into an output potential through an operational amplifier.

[0031] The output potential is:

[0032] Where i(t) is the input AC current, R is the input resistance, R1, R2, R4, and R6 are feedback resistors, and the input resistance R is 10MΩ. Operational amplifiers A1 and A2 constitute the first-stage operational amplifier, and operational amplifier A3 constitutes the second-stage differential operational amplifier. A differential circuit is used to improve the common-mode rejection ratio.

[0033] As a preferred solution of the non-contact micro-intelligent sensing optimization method for the secondary DC circuit potential of the present invention, the demodulation further includes marking the measured signal u0(t) and the reference signal u1(t) as: u1(t)=U1 sin(ωt+δ)

[0034] Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. are the phases of the measured signal and the reference signal respectively, ω is the angular frequency, and the reference signal u1(t) adopts the driving power supply of the micro Lorentz force actuator.

[0035] After the measured signal and the reference signal are simultaneously input into the multiplier and multiplied, the demodulated output response signal is:

[0036] Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. are the phases of the measured signal and the reference signal respectively, and ω is the angular frequency.

[0037] The demodulated output response signal is then filtered by a low-pass filter to remove the high-frequency AC signal in the formula. The final potential output by the signal demodulation circuit is:

[0038] The meanings of the physical quantities are the same as those defined in the above formulas.

[0039] As a preferred solution of the non-contact micro-intelligent sensing optimization method for the secondary DC circuit potential of the present invention, the comprehensive operation module analysis includes establishing a relationship between the air dielectric constant and the air temperature, humidity, and atmospheric pressure, as shown below:

[0040] Where P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, δ and t are measured by the micro temperature and humidity sensor, P is measured by the micro pressure sensor, K is the proportional constant, R g is the dry air gas constant, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature.

[0041] The corrected output potential is:

[0042] Among them, u out is the output voltage after passing through the A / D converter, P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, K is the proportional constant, R g is the dry air gas constant, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature.

[0043] As a preferred solution of the non-contact micro-intelligent sensing optimization method for the secondary DC circuit potential of the present invention, wherein: the measured potential result includes the weight per unit area of ​​the sandwich structure of the housing material of the measuring device: W = ρ1d1 + ρ2d2 + ρ3d3

[0044] Where ρ1, ρ2, and ρ3 are the material densities of the inner panel, sandwich layer, and outer panel, respectively; d1, d2, and d3 are the thicknesses of the inner panel, sandwich layer, and outer panel, respectively.

[0045] The calculation formula for the electromagnetic shielding effectiveness of the measuring device housing material is:

[0046] Where μ0 is the vacuum magnetic permeability, ε0 ​​is the vacuum electrical conductivity, σ is the volume conductivity of the material, d1, d2, and d3 are the thicknesses of the inner panel, sandwich layer, and outer panel, respectively, and c is the thickness of the material, c = d1 + d2 + d3.

[0047] The Lagrangian function is constructed using the Lagrangian multiplier method. The thickness of the inner panel, sandwich layer, and outer panel are used as variables to determine the minimum weight W of the measurement device shell while satisfying the constraints of strength, stiffness, and electromagnetic shielding effectiveness. The constructed Lagrangian function is:

[0048] Among them, λ1, λ2, λ3 are Lagrange multipliers, E f1 、E f3 is the elastic modulus parameter of the inner and outer panel materials, G f1 , G f3 is the shear modulus parameter, D1 is the initial parameter of the shell bending stiffness, K1 is the initial parameter of the shell torsional stiffness, SE1 is the minimum electromagnetic shielding effectiveness of the material, which is 58dB.

[0049] Another object of the present invention is to provide a non-contact micro-intelligent sensing optimization system for secondary DC circuit potential, which can solve problems that cannot be solved in the prior art by implementing a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential.

[0050] As a preferred solution of the non-contact micro-intelligent sensing optimization system for the secondary DC circuit potential described in the present invention, the system includes: an instruction acquisition unit for collecting instructions issued by the system; a system logic unit for carrying system calibration rules and system control logic; a data processing unit for processing data in instructions or system programs; a data storage unit for storing instructions and operations in the acquisition, calculation and driving stages; and a data console for tracking and processing the entire process of program control.

[0051] A computer device includes a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, steps of a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential are implemented.

[0052] A computer-readable storage medium stores a computer program thereon, characterized in that when the computer program is executed by a processor, the steps of a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential are implemented.

[0053] Beneficial effects of the present invention: The electromagnetically driven vibration capacitance measuring device based on the Lorentz force of the present invention has the characteristics of fast response, low driving potential, large driving force and driving displacement of electromagnetic drive, and eliminates the mechanical friction existing in the traditional driving structure. Therefore, the power consumption of the magnetic drive structure measuring device based on the Lorentz force is lower than that of other driving methods under long-term operation, and its stability is higher, which also reduces the operation and maintenance cost. Based on the vibration capacitor modulation principle, considering the influence of temperature, humidity and air pressure on the measurement signal, a calculation model of temperature, humidity, air pressure and relative dielectric constant of air is established. Then, by correcting the relative dielectric constant of air that affects the capacitance measurement, the wide spectrum adaptability of the measuring element to temperature, humidity and air pressure is achieved. Based on the electromagnetic shielding principle, a composite material with high shielding effectiveness is used as a shielding layer to encapsulate the measuring element and the low-voltage secondary DC circuit to be measured, so that they are in the same electric field space and the shielding layer is grounded, thereby effectively suppressing and weakening the long-term interference of the external electromagnetic field and adjacent charged intervals, thereby improving the measurement accuracy. The operational amplifier used in the signal demodulation circuit is a three-op-amp differential amplifier, characterized by high gain, high input impedance, and a high common-mode rejection ratio. This ensures high precision and strong interference immunity in the measurement circuit. Phase-sensitive detection technology is employed in the signal demodulation circuit, offering outstanding advantages such as fast response, excellent frequency response, strong immunity to electromagnetic interference, high measurement accuracy, and enhanced operational safety. The output potential is calibrated using the linear fitting results of experimental data, ensuring that the final output potential of the intelligent sensor is the potential of the secondary DC circuit being measured. This results in a relative measurement error of less than 1%, improving measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] FIG1 is a flow chart of a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential provided by one embodiment of the present invention.

[0056] FIG2 is a schematic diagram of a vibration capacitive measurement device for a non-contact micro-intelligent sensing optimization method for a secondary DC circuit potential provided by an embodiment of the present invention.

[0057] FIG3 is a schematic diagram of a three-op-amp differential amplifier for a non-contact micro-intelligent sensing optimization method for a secondary DC circuit potential provided by an embodiment of the present invention.

[0058] FIG4 is a schematic diagram of the phase-sensitive detection principle of a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential provided by an embodiment of the present invention.

[0059] FIG5 is a schematic diagram of a fitting curve of experimental data of a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential provided by an embodiment of the present invention.

[0060] FIG6 is a schematic diagram of relative error of an intelligent sensor measured in a non-contact micro-intelligent sensing optimization method for secondary DC circuit potential provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0063] Example 1

[0064] 1 , which is a first embodiment of the present invention, provides a non-contact micro-intelligent sensing optimization method for a secondary DC circuit potential, including:

[0065] S1: The weak AC current modulation signal is demodulated by a demodulation circuit, and the weak AC current modulation signal is amplified by a three-op-amp differential amplifier to output a stable, amplified, measurable voltage signal. The voltage signal is passed through a phase-sensitive detector to remove noise signals of non-driving frequencies. The voltage signal after noise removal is filtered out by a low-pass filter to remove the AC signal and obtain a stable DC voltage signal.

[0066] The demodulation of the weak AC current modulation signal includes installing an intelligent sensor on the secondary DC circuit to be measured. Based on the vibration capacitor modulation principle, the capacitance between the sensing plate and the charged body to be measured generates an alternating capacitance under the drive of a Lorentz force driver, causing the charge on the sensing plate to change periodically, and the AC current signal i(t) is collected on the sensing plate.

[0067] The AC current signal is converted into an amplified AC potential signal through a three-op-amp differential amplifier to obtain the AC potential signal u0(t).

[0068] After the AC potential signal passes through phase-sensitive detection and low-pass filter data processing, the real-time potential signal u0 of the secondary DC circuit to be tested is output.

[0069] By correcting the relative dielectric constant of air that affects capacitance measurement, the influence of temperature, humidity and air pressure on the measurement signal is resolved, and the corrected DC signal u1 is obtained.

[0070] According to the output potential u1 of the smart sensor in the potential measurement scenario, the actual output potential of the smart sensor is calibrated in combination with the fitting formula u2=ku1. The output potential of the measuring unit of the smart sensor after potential calibration is the secondary DC circuit potential to be measured.

[0071] The three-op-amp differential amplifier amplifies the output, and based on the vibration capacitance modulation principle, a back-end electrical signal detection circuit amplifies the electrical signal to generate a potential signal output. The distance between the sensing plate and the secondary DC circuit to be measured is: d = d0 + Δd sin (ωt)

[0072] Where d0 is the distance between the vibrating plate and the secondary DC circuit to be measured when the vibrating plate is in equilibrium, Δd is the vibration amplitude of the inductive plate. Once the driving structure based on the Lorentz force is selected, d0 and Δd can be obtained by measurement. ω is the angular frequency of vibration, ω = 2πf, f is the frequency of the AC current passed through the vibrating cantilever beam of the driving structure, and t is time.

[0073] Then the capacitance on the vibrating plate is:

[0074] Among them, ε is the dielectric constant of air, and S is the area of ​​the vibrating plate.

[0075] Then the induced current on the sensing plate is:

[0076] Where U is the potential difference between the sensing plate and the surface of the secondary DC circuit to be measured.

[0077] The demodulation includes that the AC current signal output by the vibration capacitance modulation circuit needs to be converted into an output potential through an operational amplifier.

[0078] The output potential is:

[0079] Where i(t) is the input AC current, R is the input resistance, R1, R2, R4, and R6 are feedback resistors, and the input resistance R is 10MΩ. Operational amplifiers A1 and A2 constitute the first-stage operational amplifier, and operational amplifier A3 constitutes the second-stage differential operational amplifier. A differential circuit is used to improve the common-mode rejection ratio.

[0080] The demodulation further includes marking the measured signal u0(t) and the reference signal u1(t) as: u1(t)=U1 sin(ωt+δ)

[0081] Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. are the phases of the measured signal and the reference signal respectively, ω is the angular frequency, and the reference signal u1(t) adopts the driving power supply of the micro Lorentz force actuator.

[0082] After the measured signal and the reference signal are simultaneously input into the multiplier and multiplied, the demodulated output response signal is:

[0083] Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. are the phases of the measured signal and the reference signal respectively, and ω is the angular frequency.

[0084] The demodulated output response signal is then filtered by a low-pass filter to remove the high-frequency AC signal in the formula. The final potential output by the signal demodulation circuit is:

[0085] The meanings of the physical quantities are the same as those defined in the above formulas.

[0086] S2: The DC voltage signal is input to the comprehensive operation module for analysis and processing to obtain the potential of the measured object.

[0087] S3: Use micro temperature, humidity and air pressure sensors to measure ambient temperature, humidity and air pressure information, input them into the comprehensive calculation module to analyze and correct the measurement potential results, and output the measurement results to the communication module for external output, supporting both analog and digital output modes.

[0088] The comprehensive calculation module analysis includes establishing a relationship between the air dielectric constant and the air temperature, humidity, and atmospheric pressure, as shown below:

[0089] Where P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, δ and t are measured by the micro temperature and humidity sensor, P is measured by the micro pressure sensor, K is the proportional constant, R g is the dry air gas constant, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature.

[0090] The corrected output potential is:

[0091] Among them, u out is the output voltage after passing through the A / D converter, P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, K is the proportional constant, R g is the dry air gas constant, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature.

[0092] The measured potential results include the weight per unit area of ​​the sandwich structure of the measuring device housing material: W = ρ1d1 + ρ2d2 + ρ3d3

[0093] Where ρ1, ρ2, and ρ3 are the material densities of the inner panel, sandwich layer, and outer panel, respectively; d1, d2, and d3 are the thicknesses of the inner panel, sandwich layer, and outer panel, respectively.

[0094] The calculation formula for the electromagnetic shielding effectiveness of the measuring device housing material is:

[0095] Where μ0 is the vacuum magnetic permeability, ε0 ​​is the vacuum electrical conductivity, σ is the volume conductivity of the material, d1, d2, and d3 are the thicknesses of the inner panel, sandwich layer, and outer panel, respectively, and c is the thickness of the material, c = d1 + d2 + d3.

[0096] The Lagrangian function is constructed using the Lagrangian multiplier method. The thickness of the inner panel, sandwich layer, and outer panel are used as variables to determine the minimum weight W of the measurement device shell while satisfying the constraints of strength, stiffness, and electromagnetic shielding effectiveness. The constructed Lagrangian function is:

[0097] Among them, λ1, λ2, λ3 are Lagrange multipliers, E f1 、E f3 is the elastic modulus parameter of the inner and outer panel materials, Gf1 , G f3 is the shear modulus parameter, D1 is the initial parameter of the shell bending stiffness, K1 is the initial parameter of the shell torsional stiffness, SE1 is the minimum electromagnetic shielding effectiveness of the material, which is 58dB.

[0098] Solving the formula, we determined that the inner panel thickness is 0.08mm, the interlayer thickness is 1mm, and the outer panel thickness is 0.5mm. The length, width, and height of the measurement device housing are 3cm, 3cm, and 4cm, respectively. The minimum housing weight is 9.9g, and the maximum electromagnetic shielding effectiveness is 63dB. This ensures the measurement device is small, lightweight, and highly resistant to electromagnetic interference.

[0099] S4: The sensing plate, micro Lorentz force driver, three-op-amp differential amplifier, phase-sensitive detector, and low-pass filter are packaged to form a potential acquisition "probe". The integrated operation module, micro temperature and humidity, air pressure sensor, and communication module are packaged to form a potential measurement "unit". The potential measurement "unit" supports the connection of multiple potential acquisition "probes".

[0100] Example 2

[0101] Referring to Figure 2, which is the second embodiment of the present invention, this embodiment provides a secondary DC circuit potential non-contact micro-intelligent sensing optimization system, which includes an instruction acquisition unit, a system logic unit, a data processing unit, a data storage unit and a data console; the instruction acquisition unit is used to collect instructions issued by the system; the system logic unit is used to carry system calibration rules and system control logic; the data processing unit is used to process data in instructions or system programs; the data storage unit is used to store instructions and operations in the acquisition, calculation and driving stages; the data console is used to track and process the entire process of program control.

[0102] Example 3

[0103] The third embodiment of the present invention is different from the first two embodiments in that:

[0104] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0106] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0107] The present application is described with reference to the flow chart and / or block diagram of the method, device (system), and computer program product according to the embodiment of the present application. It should be understood that each flow process and / or box in the flow chart and / or block diagram and the combination of the flow process and / or box in the flow chart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processing machine or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for realizing the function specified in one flow chart flow or multiple flows and / or one box or multiple boxes of the block diagram.

[0108] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0109] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0110] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0111] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0112] Example 4

[0113] Referring to Figure 5, the present invention conducted an experiment in which a smart sensor probe was fixed to a secondary DC circuit to be tested, and the potential of the secondary DC circuit was varied from -220V to 220V. The output potential of the smart sensor's potential measurement unit was recorded. During the experiment, five tests were performed at each measurement point, and the average of the five data was taken. The test results are shown in Table 1 below:

[0114] Table 1 Intelligent sensor linearity test data

[0115] From the analysis of the test data, it can be seen that the output potential of the intelligent sensor is proportional to the potential of the secondary DC circuit. The fitting curve is shown in Figure 5 using the least squares method.

[0116] The fitting curve expression of the test results is u2=ku1, where u1 is the output potential of the intelligent sensor, u2 is the secondary DC circuit potential, k is the voltage proportional coefficient, and k is 51.2.

[0117] Through the linearity test of the intelligent sensor and the use of the linear fitting results of the test data to calibrate the output potential, the final output potential of the intelligent sensor is achieved to be the potential of the secondary DC circuit to be measured, thereby improving the measurement accuracy.

[0118] Example 5

[0119] Referring to Figure 6, select the secondary DC circuit of the unoperated substation and install the smart sensor in the secondary DC circuit;

[0120] Usually, the secondary DC circuit potential is selected as ±24V, ±48V, ±110V, and ±220V respectively, and the measurement value of the smart sensor is recorded.

[0121] Analyze and compare the measurement results, and calculate the relative error of the measurement. The calculation formula of relative error is: Where u c is the measured value of the intelligent sensor, and u2 is the actual potential value of the DC secondary circuit to be measured.

[0122] Table 2 Measurement data of the tested secondary DC circuit

[0123] After analyzing and processing the test data, the measurement unit of the intelligent sensor, after potential calibration, can accurately measure the secondary DC circuit potential with an error of less than 1%. Therefore, the non-contact micro intelligent sensor for secondary DC circuit potential has very high measurement accuracy when measuring the potential of the secondary DC circuit.

[0124] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A non-contact micro-intelligent sensing optimization method for secondary DC circuit potential, characterized in that: include, The weak AC current modulation signal is demodulated by a demodulation circuit, and the weak AC current modulation signal is amplified by a three-op-amp differential amplifier to output a stable, amplified and measurable voltage signal, and the voltage signal is passed through a phase-sensitive detector to remove noise signals other than the driving frequency, and the voltage signal after noise removal is filtered out by a low-pass filter to remove the AC signal, so as to obtain a stable DC voltage signal; The DC voltage signal is input to the comprehensive operation module for analysis and processing to obtain the potential of the object being measured; Micro temperature, humidity and air pressure sensors are used to measure the ambient temperature, humidity and air pressure information, which are input into the comprehensive operation module for analysis and correction of the measured potential results. The measured results are output to the communication module for external output, supporting both analog and digital output modes. The sensing plate, micro Lorentz force driver, three-op-amp differential amplifier, phase-sensitive detector, and low-pass filter are packaged to form a potential acquisition "probe", and the comprehensive operation module, micro temperature and humidity, air pressure sensor, and communication module are packaged to form a potential measurement "unit". The potential measurement "unit" supports the access of multiple potential acquisition "probes".

2. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 1 is characterized in that: The demodulation of the weak AC current modulation signal includes installing an intelligent sensor on the secondary DC circuit to be tested, and based on the vibration capacitor modulation principle, the capacitance of the sensing plate and the charged body to be tested generates an alternating capacitance under the drive of a Lorentz force driver, causing the charge on the sensing plate to change periodically, and collecting the AC current signal i(t) on the sensing plate; The AC current signal is converted into an amplified AC potential signal through a three-op-amp differential amplifier to obtain an AC potential signal u0(t); After the AC potential signal is processed by phase-sensitive detection and low-pass filter data, the real-time potential signal u0 of the secondary DC circuit to be tested is output; By correcting the relative dielectric constant of air that affects capacitance measurement, the influence of temperature, humidity and air pressure on the measurement signal is resolved, and the corrected DC signal u1 is obtained; According to the output potential u1 of the smart sensor in the potential measurement scenario, the actual output potential of the smart sensor is calibrated in combination with the fitting formula u2=ku1. The output potential of the measuring unit of the smart sensor after potential calibration is the secondary DC circuit potential to be measured.

3. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 2 is characterized in that: The three-op-amp differential amplifier amplifies the output, and based on the vibration capacitance modulation principle, a back-end electrical signal detection circuit amplifies the electrical signal to generate a potential signal output. The distance between the sensing plate and the secondary DC circuit to be measured is: d = d0 + Δd sin (ωt) Wherein, d0 is the distance between the vibrating plate and the secondary DC circuit to be measured when the vibrating plate is in a balanced position, Δd is the vibration amplitude of the induction plate, and when the driving structure based on the Lorentz force is selected, d0 and Δd can be obtained by measurement, ω is the angular frequency of vibration, ω=2πf, f is the frequency of the alternating current introduced into the vibrating cantilever beam of the driving structure, and t is the time; Then the capacitance on the vibrating plate is: Among them, ε is the dielectric constant of air, S is the area of ​​the vibrating plate; Then the induced current on the sensing plate is: Wherein, U is the potential difference between the sensing plate and the surface of the secondary DC circuit to be measured.

4. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 3 is characterized in that: The demodulation includes that the AC current signal output by the vibration capacitance modulation circuit needs to be converted into an output potential by an operational amplifier, The output potential is: Among them, i(t) is the input AC current, R is the input resistance, R1, R2, R4, R6 are feedback resistors, the input resistance R is 10MΩ, operational amplifiers A1 and A2 constitute the first-stage operational amplifier, operational amplifier A3 constitutes the second-stage differential operational amplifier, and a differential circuit is used to improve the common mode rejection ratio.

5. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 4, characterized in that: The demodulation also includes marking the measured signal u0(t) and the reference signal u1(t) as: u1(t)=U1sin(ωt+δ) Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. δ is the phase of the measured signal and the reference signal, ω is the angular frequency, and the reference signal u1(t) adopts the driving power supply of the micro-Lorentz force actuator; After the measured signal and the reference signal are simultaneously input into the multiplier and multiplied, the demodulated output response signal is: Among them, U0 and U1 are the amplitudes of the measured signal and the reference signal respectively. δ is the phase of the measured signal and the reference signal, ω is the angular frequency; The demodulated output response signal is then filtered by a low-pass filter, and the high-frequency AC signal in the formula is removed. The final potential output by the signal demodulation circuit is:

6. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 5, characterized in that: The comprehensive operation module analysis includes establishing a relationship between the air dielectric constant and the air temperature, humidity, and atmospheric pressure, as shown below: Where P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, δ and t are measured by the micro temperature and humidity sensor, P is measured by the micro pressure sensor, K is the proportional constant, R g is the gas constant for dry air, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature; The corrected output potential is: Among them, u out is the output voltage after passing through the A / D converter, P is the atmospheric pressure, δ is the relative humidity of the air, t is the Celsius temperature, K is the proportional constant, R g is the gas constant for dry air, R s is the water vapor gas constant, p s is the saturated water vapor pressure at the corresponding ambient temperature.

7. The non-contact micro-intelligent sensing optimization method for secondary DC circuit potential according to claim 6, characterized in that: The measured potential results include that the unit area weight of the sandwich structure of the housing material of the measuring device is: W = ρ1d1 + ρ2d2 + ρ3d3 In the formula, ρ1, ρ2, ρ3 are the material densities of the inner panel, sandwich layer, and outer panel, respectively; d1, d2, d3 are the thicknesses of the inner panel, sandwich layer, and outer panel, respectively. The calculation formula for the electromagnetic shielding effectiveness of the measuring device housing material is: Wherein, μ0 is the vacuum magnetic permeability, ε0 ​​is the vacuum electrical conductivity, σ is the volume conductivity of the material, d1, d2, d3 are the thickness of the inner panel, sandwich layer, and outer panel respectively, and c is the thickness of the material c=d1+d2+d3; The Lagrangian function is constructed by using the Lagrangian multiplier method. The thickness of the inner panel, sandwich layer, and outer panel are taken as variables to find the minimum weight W of the measuring device shell under the constraints of strength, stiffness, and electromagnetic shielding effectiveness. The constructed Lagrangian function is: Among them, λ1, λ2, λ3 are Lagrange multipliers, E f1 、E f3 is the elastic modulus parameter of the inner and outer panel materials, G f1 , G f3 is the shear modulus parameter, D1 is the initial parameter of the shell bending stiffness, K1 is the initial parameter of the shell torsional stiffness, SE1 is the minimum electromagnetic shielding effectiveness of the material, which is 58dB.

8. A system using the non-contact micro-intelligent sensing optimization method for secondary DC circuit potential as claimed in any one of claims 1 to 7, characterized in that: The system comprises, An instruction collection unit, used for collecting instructions issued by the system; System logic unit, used to carry system calibration rules and system control logic; A data processing unit is used to process data in instructions or system programs; A data storage unit, used to store the instructions and operations in the acquisition, calculation and driving stages; The data console tracks and processes the entire process of program control.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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