Isotropic broadband voltage measurement method and sensing system

Abstract

An isotropic broadband voltage measurement method and sensing system are proposed. The distributed capacitance between the modulated spherical electric field coupled voltage sensor and the conductor under test, the stray capacitance to ground, and the grounding measurement resistance satisfy the first constraint condition. A differential input circuit is connected between each pair of electrodes in the spherical electric field coupled voltage sensor. Simultaneously, the distance between the spherical electric field coupled voltage sensor and the conductor under test, as well as the distance between each pair of electrodes in the spherical electric field coupled voltage sensor, are adjusted so that the mutual capacitance between each pair of electrodes and the conductor under test simultaneously satisfies the second and third constraint conditions. The modulated spherical electric field coupled voltage sensor is used to acquire the spatial electric field differential signal of the line and calculate the voltage distribution on the line. The adaptive differential evolution NSGA-III-JADE method is used to determine the inverted voltage on the line from the voltage distribution on the line, achieving broadband measurement of line voltage with a bandwidth of 50Hz to 10MHz.

Description

Technical Field

[0001] This invention relates to the field of broadband voltage measurement, specifically to an isotropic broadband voltage measurement method and sensing system based on the NSGA-III-JADE algorithm. Background Technology

[0002] High-frequency harmonics and transient overvoltage components in power lines seriously affect power quality and power system safety. Therefore, wideband measurement of line voltage is of great significance.

[0003] In existing technologies, wideband voltage standard measurement is based on the frequency characteristics of the wideband standard measuring device itself, selecting the lower and upper limits of the frequency waveform for tracing, which greatly reduces the difficulty of tracing. The wideband voltage standard measuring device includes a wideband voltage divider and a secondary measuring device. The voltage signal is first transformed by the wideband voltage divider and then sequentially enters the measuring device for secondary voltage transformation and acquisition. The two processes are relatively independent. The voltage scale factor of the measuring device is the product of the voltage scale factors of the voltage divider and the secondary measuring device. By tracing the voltage scale factor of the voltage divider and the secondary measuring device separately, the tracing method becomes more operational. Since the impulse waveform is a non-repetitive frequency waveform, its frequency components are very complex. Therefore, the amplitude-frequency characteristics are more suitable for tracing the repetitive frequency AC current, while evaluating its dynamic characteristics is more reasonable for impulse voltage. The wideband transient voltage divider measurement device includes a high-voltage arm unit, which divides the high voltage of the tested line to obtain a low-voltage divider and sends the low-voltage divider to a low-voltage arm unit; the low-voltage arm unit sends the low-voltage divider to a wideband transient measurement unit; and the wideband transient measurement unit measures the low-voltage divider sent by the low-voltage arm unit and determines the high voltage of the tested line based on the low-voltage divider and the voltage division ratio. The device uses low-inductance ceramic capacitors and non-inductive resistors in multi-stage series connection, allowing direct connection to the transmission line for real-time measurement of the high voltage of the tested circuit. The device can measure high voltage amplitude, wide bandwidth, and is less affected by external environmental factors. It can determine the true waveform of overvoltages, which is of great significance for the safe and stable operation of transmission lines. However, existing technologies still use PTs for voltage measurement, where electromagnetic transformers are susceptible to ferroresonance; capacitive transformers have poor transient characteristics and may generate high-frequency resonance under high-frequency overvoltages. Electric field sensors have a wide frequency response range, effectively capturing high-frequency harmonics and transient overvoltage components, providing more comprehensive voltage signal information. However, they have strict requirements for installation location and angle. Therefore, a method capable of measuring isotropic broadband voltage is needed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an isotropic broadband voltage measurement method and system based on the NSGA-III-JADE algorithm. It achieves spatial electric field measurement using an electric field sensing probe with three symmetrically distributed pairs of electrodes. The voltage is inverted and solved using the Non-dominated Sorting Genetic Algorithm-III-Adaptive Differential Evolution with Optional External Archive (NSGA-III-JADE) based on the electric field and the distance between the probe and the line. The final voltage output is determined by combining this with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), forming an isotropic broadband voltage measurement system that achieves broadband measurement of line voltage with a bandwidth of 50Hz to 10MHz.

[0005] The present invention adopts the following technical solution.

[0006] This invention proposes an isotropic broadband voltage measurement method, which uses a spherical electric field coupled voltage sensor for measurement. The spherical electric field coupled voltage sensor includes P pairs of isotropic electric field sensing probes, each pair of probes including a pair of symmetrically distributed electrodes, comprising:

[0007] Step 1: Obtain the distributed capacitance C between the spherical electric field coupled voltage sensor and the conductor under test. t The stray capacitance C of the spherical electric field coupled voltage sensor to ground d And the grounding measurement resistor R connected to the spherical electric field coupled voltage sensor. m When the three modulation parameters satisfy the first constraint condition, proceed to step 2.

[0008] Step 2: In the spherical electric field coupled voltage sensor, a differential input circuit is connected between each pair of electrodes, and the mutual capacitance C between each pair of electrodes after connecting the differential input circuit is obtained. m0 The mutual capacitance C between each pair of electrodes and the conductor being measured m Simultaneously adjust the distance between the spherical electric field coupled voltage sensor and the conductor being measured, as well as the distance between each pair of electrodes in the spherical electric field coupled voltage sensor. When the mutual capacitance C between each pair of electrodes and the conductor being measured... m0 If both the second and third constraints are met, proceed to step 3.

[0009] Step 3: The spatial electric field differential signal of the line is acquired using a modulated spherical electric field coupled voltage sensor; the voltage distribution on the line is calculated based on the spatial electric field differential signal; the inverse voltage on the line is determined from the voltage distribution on the line using the adaptive differential evolution NSGA-III-JADE method, which is used as the voltage measurement result.

[0010] Preferably, the first constraint condition is: (C t +C d )R m It is greater than the first set threshold, and the first set threshold is not less than 10.

[0011] Preferably, the second constraint is: C m0 / C m It is greater than the second set threshold, and the value of the second set threshold is not less than 10.

[0012] Preferably, the third constraint is: C m0 / C d It is greater than the third set threshold, and the value of the third set threshold is not less than 10.

[0013] Preferably, when the first constraint condition is met, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship:

[0014]

[0015] In the formula, H s (s) is the transfer function of the spherical electric field coupled voltage sensor when the first constraint condition is met. V is the frequency domain signal of the equivalent potential of the conductor being measured. s (s) represents the frequency domain signal of the output voltage of the spherical electric field coupled voltage sensor.

[0016] Preferably, when the first constraint, the second constraint, and the third constraint are satisfied, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship:

[0017]

[0018] In the formula, H s ′(s) is the transfer function of the spherical electric field coupled voltage sensor when the first, second, and third constraints are satisfied. V is the frequency domain signal of the equivalent potential of the conductor being measured. s (s) represents the frequency domain signal of the output voltage of the spherical electric field coupled voltage sensor.

[0019] Preferably, step 3 includes:

[0020] Step 3.1: Use a differential input circuit to obtain the spatial electric field differential signal of the line; calculate the voltage distribution on the line based on the spatial electric field differential signal of the line.

[0021] Step 3.2: Obtain the calculated electric field value based on the voltage distribution on the line; adopt the adaptive differential evolution NSGA-III-JADE method, with the goal of minimizing the mean square error between the actual measured electric field value and the calculated electric field value, to obtain the inverted voltage of the line from the voltage distribution, which is used as the voltage measurement result.

[0022] Preferably, step 3.2 includes:

[0023] 1) Set up an initial population; each measurement point on the line corresponds to a voltage distribution value, and each individual in the initial population represents a voltage distribution value, which is a candidate solution for inverting the voltage.

[0024] 2) Suppose there are N voltage distribution values ​​V1, V2, ..., V in the population. N Each voltage distribution value corresponds to a calculated electric field value; the optimization objective is to minimize the mean square error between the actual measured electric field value and the calculated electric field value, satisfying the following relationship:

[0025]

[0026] In the formula, f i (x) represents the optimization objective value at the i-th measurement point under decision variable x; This represents the actual measured value of the j-th dimension electric field at the i-th measurement point; The electric field value in dimension j is calculated based on the voltage distribution at the i-th measurement point under the decision variable x; M is the electric field dimension.

[0027] 3) Based on the optimization objective, the voltage distribution values ​​are non-dominated and sorted within the population to obtain a new population;

[0028] 4) Merge the initial population and the new population into a temporary population, and repeat steps 2) to 4) iteratively based on the temporary population; when the number of iterations is reached, use the TOPSIS method to determine the inversion voltage of the line in the temporary population obtained in the last iteration.

[0029] Preferably, the voltage distribution values ​​are non-dominated and ordered within the population according to the optimization objective to obtain a new population, including:

[0030] 3.1) Under decision variables p and q respectively, the optimization objective value at the i-th measurement point satisfies f i (p)≤f i (q) and there exists an optimization objective value at at least one measurement point that satisfies f j (p)<fj When (q), it represents that individual p dominates individual q; the population is divided into multiple fronts, the first front contains all non-dominated solutions, the second front contains solutions dominated by the first front but not by the second front, and so on.

[0031] 3.2) Randomly select three different individuals x from different frontiers. r1 x r2 x r3 Based on the decision variable x at the i-th measurement point i A new individual v is generated using the following relation. i :

[0032] v i =x r1 +F·(x r2 -x r3 )+CR·(x r1 -x i )

[0033] In the formula, x r1 x r2 x r3 Three different individuals are randomly selected from different frontiers; F is the mutation scaling factor; CR is the crossover probability.

[0034] Preferably, adaptive differential evolution is performed on the mutation scaling factor and crossover probability based on the voltage level and transient voltage frequency of the conductor under test.

[0035] The present invention also proposes an isotropic broadband voltage measurement sensing system, comprising: a spherical electric field coupled voltage sensor and an electric field measuring device;

[0036] The spherical electric field coupled voltage sensor includes P pairs of isotropic electric field sensing probes, each pair of probes including a pair of symmetrically distributed electrodes, where P is an integer not less than 3; the isotropic electric field sensing probe with three pairs of symmetrically distributed electrodes includes a spherical probe.

[0037] The electric field measurement device includes: a signal conditioning module, an analog-to-digital converter module, an MCU, a ranging module, a distance display module, and a signal acquisition controller;

[0038] The spherical probe transmits the spatial electric field differential signal of the line to the signal conditioning module; the signal conditioning module is used to filter, level up, and buffer the spatial electric field differential signal of the line; the analog-to-digital conversion module is used to convert the spatial electric field differential signal output by the signal conditioning module into a digital signal and transmit it to the MCU; the MCU is used to transmit the processed signal to the signal acquisition controller, which then transmits the signal to the distance display module; the ranging module is used to measure the distance H between the ranging module and the line, and the ranging module includes an ultrasonic ranging module.

[0039] Preferably, the spherical probe includes an AA′ plate, a BB′ plate, and a CC′ plate; the spatial electric field differential signal of the circuit is measured using the AA′ plate, BB′ plate, and CC′ plate, and the structural parameters of each plate satisfy the following relationship:

[0040]

[0041] Where θ is the azimuth angle of the probe. The elevation angle of the probe.

[0042] Preferably, the spherical probe is mounted on the upper surface of the signal acquisition controller via a retractable sensor bracket, and the ranging module is also mounted on the upper surface of the signal acquisition controller. Therefore, the distance D from the spherical probe to the line satisfies the following relationship:

[0043] D = Hhr

[0044] In the formula, h is the length of the telescopic sensor bracket, and r is the radius of the spherical probe.

[0045] Preferably, the electric field measuring device further includes: a power supply module, a communication module, a near-field alarm module, and a host computer;

[0046] The near-field alarm module is used to issue an alarm when the distance between the electric field sensing probe and the power transmission line is less than a set threshold; the communication module is used to transmit data to the host computer after selecting the wireless transmission mode or wired transmission mode according to actual needs; the power supply module is used to supply power to the signal conditioning module, analog-to-digital conversion module, MCU, ranging module, near-field alarm module, distance display module and signal acquisition controller.

[0047] The beneficial effects of this invention are as follows: Compared with the prior art, the method and system proposed in this invention utilize three pairs of symmetrically distributed spherical electrodes to measure the electric field. The electric field distortion in the electrode region is small and largely unaffected by the sensor's measurement angle, exhibiting the characteristic of isotropic measurement. Based on the NSGA-III-JADE algorithm, voltage is inverted and measured, enabling the measurement of broadband voltage signals of different levels. Furthermore, the system integrates ranging and near-field alarm functions. The ranging module provides accurate positioning, optimizes deployment, and improves the reliability of measurement data; the near-field alarm module ensures personnel safety, prevents equipment damage, and enhances system stability. The method and system proposed in this invention exhibit relatively consistent response characteristics when the probe is in different assembly orientations, with small directional errors, enabling accurate measurement of broadband voltage signals. Attached Figure Description

[0048] Figure 1 This is a flowchart of the isotropic broadband voltage measurement method proposed in this invention;

[0049] Figure 2 This is an equivalent circuit diagram of a single electrode measurement of the spherical electric field coupled voltage sensor in an embodiment of the present invention;

[0050] Figure 3 This is the equivalent circuit for measuring a pair of symmetrically distributed electrodes in the spherical electric field coupled voltage sensor in this embodiment of the invention;

[0051] Figure 4 This is a structural block diagram of the isotropic broadband voltage measurement sensing system proposed in this invention;

[0052] Figure 5 This is a schematic diagram of the measurement of the distance D from the probe to the line in an embodiment of the present invention;

[0053] Figure 6 These are the steady-state test results of the system in the embodiments of the present invention;

[0054] Figure 7 This is the test result of the system's 1.2 / 50μs transient overvoltage impulse response in this embodiment of the invention. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0056] The electric field strength around the conductor under test is proportional to the conductor's voltage, and the electric field strength decreases as the distance between the measurement point and the conductor increases. Within the frequency and size range of the conductor under test, the propagation time of electromagnetic waves can be ignored. Therefore, the conductor voltage and the electric field strength around the conductor change synchronously in time. The conductor potential can be indirectly measured by measuring the electric field strength around the conductor.

[0057] Traditional voltage transformers require an electrical connection with the conductor being measured to achieve voltage measurement. Whether it's an electromagnetic voltage transformer based on the transformer principle or a capacitive voltage transformer with an intermediate transformer, the essence of traditional voltage transformers is to transfer electric field energy between the primary and secondary sides using the magnetic field energy in the iron core as a medium. The voltage level is transformed by the turns ratio of the primary and secondary windings. This process is always accompanied by energy transfer and loss. Traditional voltage transformers may experience high-frequency oscillations due to ferroresonance, and capacitive voltage transformers also suffer from the problem of the secondary input not following changes in the primary voltage.

[0058] This invention proposes to measure voltage through electric field coupling, which directly acquires the electric field intensity signal, thereby achieving the purpose of indirectly measuring the conductor voltage. In this process, there is basically no current generated, and there is no exchange of functional quantities between the power system and the electric field measurement sensor.

[0059] This invention proposes an isotropic broadband voltage measurement method, employing a spherical electric field coupled voltage sensor. The spherical electric field coupled voltage sensor includes P pairs of isotropic electric field sensing probes, each pair of probes comprising a pair of symmetrically distributed electrodes, such as... Figure 1 As shown, it includes:

[0060] Step 1: Obtain the distributed capacitance C between the spherical electric field coupled voltage sensor and the conductor under test. t The stray capacitance C of the spherical electric field coupled voltage sensor to ground d And the grounding measurement resistor R connected to the spherical electric field coupled voltage sensor. m When the three modulation parameters satisfy the first constraint condition, proceed to step 2.

[0061] Specifically, the equivalent circuit diagram of the single electrode measurement of the spherical electric field coupled voltage sensor used in this invention is as follows: Figure 2 As shown. Figure 2 middle, V is the equivalent potential of the conductor being measured, and is the input voltage of the spherical electric field coupled voltage sensor. s V0(t) is the output voltage of the spherical electric field coupling voltage sensor, and V0(t) is the output voltage of the integrating circuit connected to the spherical electric field coupling voltage sensor; wherein, the equivalent circuit of the spherical electric field coupling voltage sensor includes: the distributed capacitance C between the sensor and the conductor being measured. t The stray capacitance C of the sensor to ground d The grounding measurement resistor R connected to the sensor m The equivalent circuit of the integrating circuit connected to the spherical electric field coupled voltage sensor includes: a first resistor R1 and a first capacitor C1.

[0062] The equivalent circuit of the spherical electric field coupled voltage sensor is a first-order RC circuit model, and the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship:

[0063]

[0064] In the formula, H s (s) is the transfer function of the spherical electric field coupled voltage sensor when the first constraint condition is met. V is the frequency domain signal of the equivalent potential of the conductor being measured. s(s) is the frequency domain signal of the output voltage of the spherical electric field coupled voltage sensor, and s is the integral operator.

[0065] When (C) t +C d )R m When << 1, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship:

[0066]

[0067] At this time, the spherical electric field coupled voltage sensor is operating in differential mode, and V0(t) and The input voltage is proportional to the differential value, requiring the connection of an integrating circuit to ensure that the input voltage of the spherical electric field coupled voltage sensor is proportional to the differential value. It has a linear relationship with the voltage V0(t) output after the integrator circuit.

[0068] When (C) t +C d )R m When >>1, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship:

[0069]

[0070] At this point, the first constraint condition is: (C t +C d )R m The value is greater than the first set threshold; the first set threshold is not less than 10; by modulation, when the first constraint condition is met, the spherical electric field coupled voltage sensor operates in self-integration mode, V s (t) and Proportional to the input voltage, the spherical electric field coupled voltage sensor can achieve the input voltage without an external integrating circuit. With output voltage V s (t) has a linear relationship.

[0071] In power systems, most voltage frequencies are within the 50Hz fundamental frequency range, but transient voltage frequencies can reach the MHz level, and the distributed capacitance C... t and stray capacitance C d For pF level, adjust the grounding measurement resistance R. m When reaching the GΩ level, it satisfies (C t +C d )R m >>1, which enables the spherical electric field coupled voltage sensor to operate in self-integration mode, ensuring the input voltage of the spherical electric field coupled voltage sensor. With output voltage V s (t) has a linear relationship, and wideband measurement is also achieved.

[0072] Therefore, this invention proposes a method to modulate the distributed capacitance C between a spherical electric field coupled voltage sensor and the conductor being measured. t The stray capacitance C of the spherical electric field coupled voltage sensor to ground d And the grounding measurement resistor R connected to the spherical electric field coupled voltage sensor. m To satisfy the first constraint condition (C) t +C d )R m When >>1, proceed to step 2.

[0073] Step 2: In the spherical electric field coupled voltage sensor, a differential input circuit is connected between each pair of electrodes, and the mutual capacitance C between each pair of electrodes after connecting the differential input circuit is obtained. m0 The mutual capacitance C between each pair of electrodes and the conductor being measured m Simultaneously adjust the distance between the spherical electric field coupled voltage sensor and the conductor being measured, as well as the distance between each pair of electrodes in the spherical electric field coupled voltage sensor. When the mutual capacitance C between each pair of electrodes and the conductor being measured... m0 If both the second and third constraints are met, proceed to step 3.

[0074] In the spherical electric field coupled voltage sensor used in this invention, the equivalent circuit for measuring a pair of symmetrically distributed electrodes is as follows: Figure 3 As shown, C m Let C be the mutual capacitance between a pair of electrodes and the conductor being measured. m The mutual capacitance C is related to the distance between the electrode and the conductor being measured, and because the distance between the electrode and the conductor being measured is relatively large, the mutual capacitance C is also relatively large. m Smaller; a differential input circuit is connected between a pair of electrodes, C m0 To determine the mutual capacitance between a pair of electrodes after connecting to the differential input circuit, since the distance between the pair of electrodes is adjustable, the mutual capacitance C between the pair of electrodes can be adjusted by changing the distance between the electrodes. m0 Much larger than the mutual capacitance C between a pair of electrodes and the conductor being measured. m And the mutual capacitance C between a pair of electrodes m0 It is also much larger than the stray capacitance C of the sensor to ground. d Therefore, in satisfying (C) t +C d )R m When the value is greater than 1, the differential input circuit will not change the transfer function of the spherical electric field coupled voltage sensor operating in self-integration mode. The transfer function satisfies the following relationship:

[0075]

[0076] In the formula, H s′(s) is the transfer function of the spherical electric field coupled voltage sensor when the first, second, and third constraints are satisfied.

[0077] Specifically, this invention employs simultaneous adjustment of the distance between the spherical electric field coupled voltage sensor and the conductor under test, and the distance between a pair of electrodes, to modulate the mutual capacitance C. m0 The second constraint condition is satisfied, and the second constraint condition is: C m0 / C m The value is greater than the second set threshold, and the third constraint is: C m0 / C d It is greater than the third set threshold, where both the second and third set thresholds are not less than 10. When C m0 >>C m And C m0 >>C d The same modulation method is used for each pair of electrodes in the spherical electric field coupled voltage sensor.

[0078] Step 3: The spatial electric field differential signal of the line is acquired using a modulated spherical electric field coupled voltage sensor; the voltage distribution on the line is calculated based on the spatial electric field differential signal; the inverse voltage on the line is determined from the voltage distribution on the line using the adaptive differential evolution NSGA-III-JADE method, which is used as the voltage measurement result.

[0079] Specifically, step 3 includes:

[0080] Step 3.1: Use a differential input circuit to obtain the spatial electric field differential signal of the line; calculate the voltage distribution on the line based on the spatial electric field differential signal of the line.

[0081] Specifically, this invention connects a differential input circuit between each pair of electrodes to acquire the spatial electric field differential signal of the line. The differential input circuit has the characteristics of resisting common-mode interference from the environment and amplifying only the differential signal, thereby significantly improving the anti-interference capability of the system and reducing the influence of stray capacitance. Therefore, this invention achieves this by connecting a differential input circuit between the three pairs of electrodes.

[0082] At each measurement point on the line, a modulated spherical electric field coupled voltage sensor is used to acquire the spatial electric field differential signal of the line. Based on the spatial electric field differential signal at each measurement point, the voltage distribution value at each measurement point on the line is calculated.

[0083] Step 3.2: Obtain the calculated electric field value based on the voltage distribution on the line; adopt the adaptive differential evolution NSGA-III-JADE method, with the goal of minimizing the mean square error between the actual measured electric field value and the calculated electric field value, to obtain the inverted voltage of the line from the voltage distribution, which is used as the voltage measurement result.

[0084] Specifically, step 3.2 includes:

[0085] 1) Set up the initial population;

[0086] Each measurement point on the line corresponds to a voltage distribution value. Each individual in the initial population represents a voltage distribution value, which is a candidate solution for inverting the voltage.

[0087] 2) Suppose there are N voltage distribution values ​​V1, V2, ..., V in the population. N Each voltage distribution value corresponds to a calculated electric field value; the optimization objective is to minimize the mean square error between the actual measured electric field value and the calculated electric field value, satisfying the following relationship:

[0088]

[0089] In the formula, f i (x) represents the optimization objective value at the i-th measurement point under decision variable x; This represents the actual measured value of the j-th dimension electric field at the i-th measurement point; The j-th dimension electric field is calculated based on the voltage distribution at the i-th measurement point under the decision variable x; M is the electric field dimension.

[0090] Using the inverted voltage of the line as the decision variable x in this invention is a non-limiting but preferred choice. When using the inverted voltage of the line as the decision variable, more accurate voltage measurement results can be obtained through optimization. Alternatively, the distance between the spherical electric field coupled voltage sensor and the conductor being measured can be used as the decision variable, and a more suitable measurement point can be obtained through optimization; alternatively, the distance between each pair of electrodes in the spherical electric field coupled voltage sensor can be used as the decision variable, and a suitable spherical electric field coupled voltage sensor structure can be obtained through optimization.

[0091] 3) Based on the optimization objective, perform non-dominated sorting of the voltage distribution values ​​within the population to obtain a new population; including:

[0092] 3.1) Under decision variables p and q respectively, the optimization objective value at the i-th measurement point satisfies f i (p)≤f i (q) and there exists an optimization objective value at at least one measurement point that satisfies f j (p)<f jWhen (q), it represents that individual p dominates individual q; the population is divided into multiple fronts, the first front contains all non-dominated solutions, the second front contains solutions dominated by the first front but not by the second front, and so on.

[0093] 3.2) Randomly select three different individuals x from different frontiers. r1 x r2 x r3 Based on the decision variable x at the i-th measurement point i A new individual v is generated using the following relation. i :

[0094] v i =x r1 +F·(x r2 -x r3 )+CR·(x r1 -x i )

[0095] In the formula, x r1 x r2 x r3 Three different individuals are randomly selected from different frontiers; F is the mutation scaling factor; CR is the crossover probability.

[0096] Among these methods, adaptive differential evolution is performed on the mutation scaling factor and crossover probability based on the voltage level and transient voltage frequency of the conductor under test. The NSGA-III-JADE method using adaptive differential evolution is a non-restrictive and preferred choice. Adaptive differential evolution not only allows the NSGA-III-JADE method to dynamically adjust mutation parameters but also retains its advantages in diversity distribution.

[0097] New individual v i Add to the new population;

[0098] 4) Merge the initial population and the new population into a temporary population, and repeat steps 2) to 4) iteratively based on the temporary population; when the number of iterations is reached, use the TOPSIS method to determine the inversion voltage of the line in the temporary population obtained in the last iteration.

[0099] This invention proposes an isotropic broadband voltage measurement method based on the NSGA-III-JADE algorithm, which has a wide frequency response range and enables accurate measurement of space vector electric fields. The NSGA-III-JADE algorithm is introduced for voltage measurement inversion calculation, and combined with the TOPSIS algorithm, high-precision and reliable measurement of broadband voltage signals is achieved.

[0100] This invention also proposes an isotropic broadband voltage measurement sensing system, such as... Figure 4As shown, it includes: a spherical electric field coupling voltage sensor and an electric field measuring device; wherein, the spherical electric field coupling voltage sensor includes P pairs of isotropic electric field sensing probes, each pair of probes includes a pair of symmetrically distributed electrodes, and P is an integer not less than 3.

[0101] This invention proposes using an isotropic electric field sensing probe with three pairs of electrodes symmetrically distributed to acquire the spatial electric field differential signal of a circuit. Then, an electric field measuring device is used to obtain the spatial electric field of the circuit based on the spatial electric field differential signal. Simultaneously, the distance from the electric field sensing probe to the circuit is also obtained using the electric field measuring device. This is a non-limiting but preferred option; those skilled in the art can use different probes and electric field measuring devices to obtain the spatial electric field of the circuit and the distance from the electric field sensing probe to the circuit, depending on the actual situation.

[0102] In a non-limiting preferred embodiment, the isotropic electric field sensing probe with three pairs of electrodes symmetrically distributed includes, but is not limited to, a spherical probe, such as... Figure 2 As shown, the spherical probe includes plates AA′, BB′, and CC′. The spatial electric field differential signal of the circuit is measured using plates AA′, BB′, and CC′. The structural parameters of each plate satisfy the following relationship:

[0103]

[0104] Where θ is the azimuth angle of the probe. The elevation angle of the probe.

[0105] The isotropic voltage of the electric field in the line space is measured using an isotropic electric field sensing probe with three pairs of electrodes symmetrically distributed.

[0106] In a non-limiting preferred embodiment, such as Figure 4 and Figure 5 As shown, the electric field measurement device includes, but is not limited to: a signal conditioning module, an analog-to-digital conversion module, a power supply module, an MCU, a communication module, a ranging module, a near-field alarm module, a distance display module, a signal acquisition controller, and a host computer. Among these,

[0107] The spherical probe transmits the spatial electric field differential signal of the line to the signal conditioning module; the signal conditioning module is used to filter, level up, and buffer the spatial electric field differential signal of the line; the analog-to-digital conversion module is used to convert the spatial electric field differential signal output by the signal conditioning module into a digital signal and transmit it to the MCU; the ranging module is used to measure the distance H between the ranging module and the line, and the ranging module includes, but is not limited to, an ultrasonic ranging module;

[0108] like Figure 5As shown, the spherical probe is mounted on the upper surface of the signal acquisition controller via a retractable sensor bracket, and the ranging module is also mounted on the upper surface of the signal acquisition controller. Therefore, the distance D from the spherical probe to the line satisfies the following relationship:

[0109] D = Hhr

[0110] In the formula, h is the length of the telescopic sensor bracket, and r is the radius of the spherical probe.

[0111] The near-field alarm module is used to issue an alarm when the distance between the electric field sensing probe and the power transmission line is less than a set threshold, thereby ensuring that the working environment is within a safe range; the communication module is used to transmit data to the host computer after selecting wireless or wired transmission mode according to actual needs; the power supply module is used to supply power to the signal conditioning module, analog-to-digital conversion module, MCU, ranging module, near-field alarm module, distance display module, and signal acquisition controller.

[0112] Ultimately, the electric field measurement device outputs the spatial electric field signal of the line and the distance from the electric field sensing probe to the line.

[0113] Before using the system, a calibration test must be conducted. The system is placed below known voltage waveforms of different levels, the probe is adjusted to different heights, the system output and the known voltage waveform are calibrated, and the system performance is verified.

[0114] The workflow of the isotropic broadband voltage measurement sensing system proposed in this invention includes:

[0115] 1) Arrange the probes and trigger an alarm when the probes are too close to the line. Readjust the sensor height until the measurement requirements are met.

[0116] 2) After the probe signal is filtered, amplified, and conditioned, the processed signal is transmitted to the signal acquisition controller;

[0117] 3) The signal acquisition controller transmits the signal to the display terminal to complete the voltage inversion calculation and draw the waveform.

[0118] The electric field measurement device and display terminal can be selected via wired / wireless means according to requirements and usage scenarios. The display terminal performs voltage inversion calculation based on the electric field and probe-line distance D data provided by the electric field measurement device, and reconstructs the voltage waveform of each phase based on the calculation results.

[0119] The steady-state, transient, and angle deviation resistance test results of this invention are as follows:

[0120] Figure 6 The steady-state test results of the system designed in this invention are shown. The transient test results of the system designed in this invention are as follows: Figure 7The three-phase output of the arc-surface six-electrode electric field sensor has good tracking performance. Within this excitation range, the phase difference between each signal is less than 1.8°, and the delay of the three-dimensional electric field component signal compared with the standard source signal is less than 0.56μs.

[0121] Rotation was performed along the x, y, and z axes, and combinations thereof, by 45°, 90°, and 135°, respectively. For example, (45°, 0°, 0°) represents a 45° center angle deflection along the x-axis, while (45°, 45°, 45°) represents a 45° angle deflection along the x, y, and z axes respectively. A total of 13 sets of different deviation angle combinations were tested, with each set measured 5 times to obtain the amplitude error and standard deviation of the test results. The standard deviation is characterized by the amplitude error from multiple measurements. The overall test results are shown in Table 1.

[0122] Table 1. Sensor response characteristics under different bias angles

[0123]

[0124] When the sensor is in the positive definite position (0°, 0°, 0°), its electric field amplitude measurement error is less than 2%, and both the standard deviation and uncertainty are very small. This proves that the sensor's electric field amplitude measurement via three-dimensional electric field component vector synthesis has good accuracy and stability. Therefore, the isotropic broadband voltage measurement method and system designed in this invention have the advantages of small size, simple structural design, wide response bandwidth, high steady-state measurement accuracy, and fast transient response. It is suitable for broadband measurement scenarios involving power frequency, harmonics, and transient voltages.

[0125] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0126] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0127] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0128] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. An isotropic broadband voltage measurement method, employing a spherical electric field coupled voltage sensor for measurement, the spherical electric field coupled voltage sensor comprising P pairs of isotropic electric field sensing probes, where P is an integer not less than 3, each pair of probes comprising a pair of symmetrically distributed electrodes, characterized in that... include: Step 1: Obtain the distributed capacitance C between the spherical electric field coupled voltage sensor and the conductor under test. t The stray capacitance C of the spherical electric field coupled voltage sensor to ground d And the grounding measurement resistor R connected to the spherical electric field coupled voltage sensor. m When the three modulation parameters satisfy the first constraint condition, proceed to step 2; the first constraint condition is: (C t +C d )R m Greater than the first set threshold; Step 2: In the spherical electric field coupled voltage sensor, a differential input circuit is connected between each pair of electrodes, and the mutual capacitance C between each pair of electrodes after connecting the differential input circuit is obtained. m0 The mutual capacitance C between each pair of electrodes and the conductor being measured m Simultaneously adjust the distance between the spherical electric field coupled voltage sensor and the conductor being measured, as well as the distance between each pair of electrodes in the spherical electric field coupled voltage sensor. When the mutual capacitance C between each pair of electrodes... m0 If both the second and third constraints are satisfied, proceed to step 3; the second constraint is: C m0 / C m Greater than the second set threshold; the third constraint is: C m0 / C d The value is greater than the third set threshold; the first, second, and third set thresholds are all not less than 10. Step 3: The spatial electric field differential signal of the line is acquired using a modulated spherical electric field coupled voltage sensor; the voltage distribution on the line is calculated based on the spatial electric field differential signal; the inverse voltage on the line is determined from the voltage distribution on the line using the adaptive differential evolution NSGA-III-JADE method, which is used as the voltage measurement result.

2. The isotropic broadband voltage measurement method according to claim 1, characterized in that, When the first constraint condition is met, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship: In the formula, H s (s) is the transfer function of the spherical electric field coupled voltage sensor when the first constraint condition is met. V is the frequency domain signal of the equivalent potential of the conductor being measured. s (s) represents the frequency domain signal of the output voltage of the spherical electric field coupled voltage sensor.

3. The isotropic broadband voltage measurement method according to claim 1, characterized in that, When the first, second, and third constraints are met, the transfer function of the spherical electric field coupled voltage sensor satisfies the following relationship: In the formula, H s ′(s) is the transfer function of the spherical electric field coupled voltage sensor when the first, second, and third constraints are satisfied. V is the frequency domain signal of the equivalent potential of the conductor being measured. s (s) represents the frequency domain signal of the output voltage of the spherical electric field coupled voltage sensor.

4. The isotropic broadband voltage measurement method according to claim 1, characterized in that, Step 3 includes: Step 3.1: Use a differential input circuit to obtain the spatial electric field differential signal of the line; calculate the voltage distribution on the line based on the spatial electric field differential signal of the line. Step 3.2: Obtain the calculated electric field value based on the voltage distribution on the line; adopt the adaptive differential evolution NSGA-III-JADE method, with the goal of minimizing the mean square error between the actual measured electric field value and the calculated electric field value, to obtain the inverted voltage of the line from the voltage distribution, which is used as the voltage measurement result.

5. The isotropic broadband voltage measurement method according to claim 4, characterized in that, Step 3.2 includes: 1) Set up an initial population; each measurement point on the line corresponds to a voltage distribution value, and each individual in the initial population represents a voltage distribution value, which is a candidate solution for inverting the voltage. 2) Suppose there are N voltage distribution values ​​V1, V2, ..., V in the population. N Each voltage distribution value corresponds to a calculated electric field value; the optimization objective is to minimize the mean square error between the actual measured electric field value and the calculated electric field value, satisfying the following relationship: In the formula, f i (x) represents the optimization objective value at the i-th measurement point under decision variable x; This represents the actual measured value of the j-th dimension electric field at the i-th measurement point; The electric field value in dimension j is calculated based on the voltage distribution at the i-th measurement point under the decision variable x; M is the electric field dimension. 3) Based on the optimization objective, the voltage distribution values ​​are non-dominated and sorted within the population to obtain a new population; 4) Merge the initial population and the new population into a temporary population, and repeat steps 2) to 4) iteratively based on the temporary population; when the number of iterations is reached, use the TOPSIS method to determine the inversion voltage of the line in the temporary population obtained in the last iteration.

6. The isotropic broadband voltage measurement method according to claim 5, characterized in that, Within the population, the voltage distribution values ​​are non-dominated and sorted according to the optimization objective to obtain a new population, including: 3.1) Under decision variables p and q respectively, the optimization objective value at the i-th measurement point satisfies f i (p)≤f i (q) and there exists an optimization objective value at at least one measurement point that satisfies f j (p) <f j When (q), it represents that individual p dominates individual q; the population is divided into multiple fronts, the first front contains all non-dominated solutions, the second front contains solutions dominated by the first front but not by the second front, and so on. 3.2) Randomly select three different individuals x from different frontiers. r1 x r2 x r3 Based on the decision variable x at the i-th measurement point i A new individual v is generated using the following relation. i : v i =x r1 +F·(x r2 -x r3 )+CR·(x r1 -x i ) In the formula, x r1 x r2 x r3 Three different individuals are randomly selected from different frontiers; F is the mutation scaling factor; CR is the crossover probability.

7. The isotropic broadband voltage measurement method according to claim 6, characterized in that, Adaptive differential evolution is performed on the mutation scaling factor and crossover probability based on the voltage level and transient voltage frequency of the conductor under test.

8. An isotropic broadband voltage measurement sensing system, characterized in that, include: Spherical electric field coupling voltage sensor and electric field measurement device; The spherical electric field coupled voltage sensor includes P pairs of isotropic electric field sensing probes, each pair of probes including a pair of symmetrically distributed electrodes, where P is an integer not less than 3; the three pairs of symmetrically distributed isotropic electric field sensing probes include spherical probes; the spherical probes include AA′ plate, BB′ plate, and CC′ plate; the spatial electric field differential signal of the circuit is measured using the AA′ plate, BB′ plate, and CC′ plate, and the structural parameters of each plate satisfy the following relationship: Where θ is the azimuth angle of the probe. The probe's elevation angle; The electric field measurement device includes: a signal conditioning module, an analog-to-digital converter module, an MCU, a ranging module, a distance display module, and a signal acquisition controller; The spherical probe transmits the spatial electric field differential signal of the line to the signal conditioning module; the signal conditioning module is used to filter, level up, and buffer the spatial electric field differential signal of the line; the analog-to-digital conversion module is used to convert the spatial electric field differential signal output by the signal conditioning module into a digital signal and transmit it to the MCU; the MCU is used to transmit the processed signal to the signal acquisition controller, which then transmits the signal to the distance display module; the ranging module is used to measure the distance H between the ranging module and the line, and the ranging module includes an ultrasonic ranging module.

9. The isotropic broadband voltage measurement sensing system according to claim 8, characterized in that, The spherical probe is mounted on the upper surface of the signal acquisition controller via a retractable sensor bracket. The ranging module is also mounted on the upper surface of the signal acquisition controller. Therefore, the distance D from the spherical probe to the line satisfies the following relationship: D = Hhr In the formula, h is the length of the telescopic sensor bracket, and r is the radius of the spherical probe.

10. The isotropic broadband voltage measurement sensing system according to claim 8, characterized in that, The electric field measurement device also includes: a power supply module, a communication module, a near-field alarm module, and a host computer; The near-field alarm module is used to issue an alarm when the distance between the electric field sensing probe and the power transmission line is less than a set threshold; the communication module is used to transmit data to the host computer after selecting the wireless transmission mode or wired transmission mode according to actual needs; the power supply module is used to supply power to the signal conditioning module, analog-to-digital conversion module, MCU, ranging module, near-field alarm module, distance display module and signal acquisition controller.

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