Non-intrusive magnetoelectric field source collaborative self-energy-taking pressure flow synchronous measurement data inversion processing method

Abstract

The invention discloses a non-intrusive magnetoelectric field source collaborative self-energy-taking voltage and current synchronous measurement data inversion processing method, which comprises the following steps of: when the voltage of a test capacitor reaches a discharge threshold voltage, calculating the voltage amplitude of a through-flow conductor by testing the charging time of the capacitor; the hysteresis comparison circuit outputs a high level, and a relative coordinate system is established by taking the moment as a zero point; acquiring a plurality of current real-time values in a power frequency period, calculating the amplitude and phase of the current of the through-flow conductor, and drawing a current waveform; the sinusoidal voltage waveform of the through-flow conductor is converted into a square wave, the moment when a first complete high level is obtained is recorded, and the difference value between the moment and the moment when the hysteresis comparison circuit outputs a high level signal is calculated; according to the real-time value of the current, the voltage amplitude of the through-flow conductor and the difference value, the waveforms of the voltage and the current of the through-flow conductor are restored to the relative coordinate system, and the phase difference between the voltage and the current is calculated. According to the method, the change of voltage and current can be synchronously tracked without a reliable external power supply, and high precision and high reliability of a measurement result are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the field of self-powered voltage and current synchronous measurement data processing methods, and particularly relates to a non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method. Background Art

[0002] In modern power systems, electronic devices, and automation control fields, voltage and current synchronous measurement technology has become extremely crucial. With the rapid development of technology and the continuous acceleration of the industrialization process, people's requirements for power quality, equipment efficiency, and system stability are more stringent. The past traditional single-parameter measurement methods are inadequate in the face of today's complex and changing actual needs. Therefore, the voltage and current synchronous measurement technology emerged, which provides strong support for ensuring the safe and efficient operation of power systems, optimizing the performance of electronic devices, and achieving precise control. However, there are still some deficiencies in the existing voltage and current synchronous measurement technologies. In terms of hardware, the digital signals output by the ADC need subsequent signal processing, such as filtering, amplification, FFT operations, etc. If the processing capabilities of the ADC itself or the signal processing circuit cooperating with it are insufficient, it may lead to untimely data processing and inaccurate results, affecting the efficiency and accuracy of synchronous measurement; when transmitting measurement data to the upper computer or other devices for analysis and processing, it may be affected by problems such as network transmission delay and packet loss. At the same time, in order to achieve high-precision voltage and current synchronous measurement, the hardware circuit may be designed more complexly, which not only increases the circuit design difficulty and cost but also may lead to a decrease in system reliability. In terms of software, in actual measurement, signals are often interfered by noise, such as a large number of non-linear loads in the power grid generating noise. Some algorithms have insufficient noise suppression capabilities, and noise may cause pseudo-fluctuations in the amplitude and phase angle of the measured phasor. Especially for parameters calculated through the phase angle derivative, such as frequency and frequency change rate, the tiny phase angle fluctuations caused by noise may significantly increase the measurement error. For a large amount of voltage and current data obtained by high-frequency sampling, the processing speed of some data processing software or algorithms is slow and difficult to meet the real-time requirements. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method to achieve synchronous data processing of voltage and current amplitudes and phases.

[0004] Technical Solution: The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method of the present invention includes the following steps:

[0005] The energy-taking electrode plate charges the test capacitor through a current-carrying conductor. When the voltage across the test capacitor reaches the discharge threshold voltage, the charging time t is recorded, and the voltage amplitude of the current-carrying conductor is calculated based on the charging time t. The hysteresis comparison circuit outputs a high level, and the test capacitor releases energy. A relative coordinate system is established with the moment when the hysteresis comparison circuit outputs a high level as the zero point.

[0006] The microprocessor obtains several equally spaced real-time current values within a power frequency cycle, calculates the amplitude and phase of the current in the current-carrying conductor, and plots the current waveform.

[0007] The sinusoidal voltage of the current-carrying conductor is converted into a square wave. The start time of obtaining the complete high level of the first square wave voltage of the current-carrying conductor is recorded, and the difference between this time and the time when the hysteresis comparison circuit outputs a high-level signal is calculated.

[0008] Based on the real-time value of the current in the current-carrying conductor, the voltage amplitude of the current-carrying conductor, and the difference between the start time of obtaining the complete high level of the first square wave voltage of the current-carrying conductor and the time when the hysteresis comparison circuit outputs a high-level signal, the waveforms of the voltage and current of the current-carrying conductor are restored to the relative coordinate system with the moment when the hysteresis comparison circuit outputs a high-level signal as the zero point, and the voltage-current phase difference is calculated.

[0009] Furthermore, the voltage amplitude of the current-carrying conductor adopts an inversion measurement method, specifically:

[0010]

[0011] where U p is the voltage of the current-carrying conductor, U ct is the charging voltage of the fixed test capacitor, U0 is the initial voltage of the test capacitor, C t is the capacitance value of the test capacitor, ω is the power frequency angular frequency, C2 is the coupling capacitance between the energy-taking electrode plate and the ground corrected according to the inversion voltage error value, and t is the charging time for the voltage of the test capacitor to change from U0 to U ct .

[0012] Furthermore, the calculation method for the amplitude and phase of the current in the current-carrying conductor is as follows:

[0013] Based on several equally spaced real-time current values obtained within a power frequency cycle, the amplitude and phase of the current in the current-carrying conductor are calculated through the discrete data restoration method. The moment when the current changes from negative to positive is recorded as t1, and the time difference between it and the zero point of the constructed relative coordinate system is (t0 - t1).

[0014] Furthermore, the discrete data restoration method adopts the full-wave Fourier algorithm. If the original analog signal is a periodic function, its Fourier series form is:

[0015]

[0016] Among them, \(x(t)\) is a function of the current of the current-carrying conductor with respect to \(t\), the angular frequency of the original analog signal is \(\omega_1\), \(n = 0, 1, 2, \cdots\infty\), \(a\) n represents the amplitude of the non-sinusoidal part of the \(n\)th harmonic, \(b\) n represents the amplitude of the sinusoidal part of the \(n\)th harmonic. If \(n = 0\), at this time \(a_0\) represents the DC component;

[0017] When \(n = 1\), calculated according to the Fourier series, \(\alpha_1\) and \(b_1\) are calculated as follows:

[0018]

[0019]

[0020] Among them, the fundamental wave component contained in \(x(t)\) is expressed in the time-frequency domain as:

[0021]

[0022] The effective value \(X\) of the fundamental wave quantity and the initialized phase \(\theta_0\) are calculated from the above formula as follows:

[0023] 2X 2 = a1 2 + b1 2

[0024]

[0025] The calculation formulas for \(a_1\) and \(b_1\) are:

[0026]

[0027]

[0028] Among them, \(x\) k is the actual value represented by the \(k\)th real-time current sampling point, \(k\) is the ordinal number of the real-time current sampling point, \(k = 0, 1, 2, \cdots, N\), and \(N\) is the number of real-time current value sampling points within a power frequency cycle;

[0029] Similarly, when \(n\) is any value, \(a\) n and \(b\) n are calculated as follows:

[0030]

[0031]

[0032] Further, during voltage phase measurement, timing is performed after the microprocessor receives the 3.3V buck high-level signal. When the microprocessor receives the first complete high-level signal of the current-carrying conductor square-wave voltage, the start time t2 of the microprocessor receiving the complete high-level signal of the square-wave voltage is output. This time is the time when the first complete low-level of the current-carrying conductor voltage is generated, and the time difference from the relative zero point is (t2 - t0).

[0033] Further, after the voltage and current waveforms restored according to the amplitudes and phases of the voltage and current are placed in the constructed relative coordinate system, the phase difference between the two waveforms needs to be further calculated and processed. The time when the current changes from negative to positive is obtained as t1 through the data restoration method. The current phase is obtained by calculating the time difference (t0 - t1) from the zero point of the constructed relative coordinate system. The voltage phase is obtained by calculating the time difference (t2 - t0) between the start time t2 of the microprocessor receiving the first complete high-level signal of the current-carrying conductor square-wave voltage and the zero point t0 of the relative coordinate system. Finally, the phase difference between the current and voltage, that is, the power factor angle, is obtained.

[0034] Further, the relationship between the time t1 when the current changes from negative to positive and the time t2 when the microprocessor receives the first complete high-level signal of the current-carrying conductor square-wave voltage includes four cases;

[0035] The voltage leads the current and the voltage square wave is at a low level at the zero point of the relative coordinate system, the voltage lags behind the current and the voltage square wave is at a low level at the zero point of the relative coordinate system, the voltage leads the current and the voltage square wave is at a high level at the zero point of the relative coordinate system, the voltage lags behind the current and the voltage square wave is at a high level at the zero point of the relative coordinate system. The relationships between the phase θ1 of the current relative to the relative zero point and the phase θ2 of the voltage relative to the relative zero point are as follows:

[0036]

[0037] On the other hand of the present invention, a non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing system includes:

[0038] A voltage amplitude calculation unit, which is used for the energy-taking plate to charge the test capacitor through the current-carrying conductor. When the voltage across the test capacitor reaches the discharge threshold voltage, the charging time t is recorded, and the voltage amplitude of the current-carrying conductor is calculated through the charging time t; the hysteresis comparison circuit outputs a high level, and a relative coordinate system is established with the time t0 when the hysteresis comparison circuit outputs a high level as the zero point;

[0039] A current waveform drawing unit, which is used for the current waveform microprocessor to obtain a plurality of equally spaced real-time current values within a power frequency period, calculate the amplitude and phase of the current-carrying conductor current, and draw the current waveform;

[0040] A time difference calculation unit, which is used to convert the sinusoidal voltage of a current-carrying conductor into a square wave, record the start time of obtaining the complete high level of the first square wave voltage of the current-carrying conductor, and calculate the difference between this time and the time when the hysteresis comparison circuit outputs a high-level signal;

[0041] A voltage-current phase difference calculation unit, which is used to restore the waveforms of the voltage and current of the current-carrying conductor to a relative coordinate system with the time when the hysteresis comparison circuit outputs a high-level signal as the zero point according to the real-time value of the current of the current-carrying conductor, the voltage amplitude of the current-carrying conductor, and the difference between the start time of obtaining the complete high level of the first square wave voltage of the current-carrying conductor and the time when the hysteresis comparison circuit outputs a high-level signal, and calculate the voltage-current phase difference.

[0042] The electronic device for storing and executing the method of the present invention includes a memory, a processor, and a computer program / instructions stored on the memory and executable on the processor. When the computer program / instructions are executed by the processor, the steps of the non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method are implemented.

[0043] The computer-readable storage medium for storing and executing the method of the present invention stores computer instructions. When the computer instructions are called, the steps of the non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method are executed.

[0044] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: By integrating the line voltage inversion measurement technology, the line voltage phase measurement technology, and the line current measurement technology, an accurate relative coordinate system is constructed, and the collected voltage and current data are accurately positioned and processed using this coordinate system, effectively solving the problem of data processing in the process of synchronous measurement of voltage and current; This method not only successfully overcomes the inherent defects of traditional voltage-current synchronous measurement triggering technologies, such as poor data synchronization, high manufacturing costs, lack of reliable external power supply support, and the need for power-off installation, but also significantly improves the accuracy and reliability of measurement; In the application scenario of synchronous measurement of voltage and current in high-voltage transmission lines, the data processing method of the present invention shows significant economic benefits and practicality due to its simplicity and ease of implementation. Description of the Drawings

[0045] Figure 1 It is a flowchart of the method of the present invention;

[0046] Figure 2 It is a schematic diagram of a voltage measurement circuit and a relative zero point pulse;

[0047] Figure 3The process of constructing the line current signal, where (a) is the discrete current data received by the microprocessor, and (b) is the restored current waveform processed by the discrete data processing method;

[0048] Figure 4 The process diagram of restoring the current-voltage waveform in the relative coordinate system, where (a) is the relative coordinate system, (b) is the restored current waveform in the conventional coordinate system, (c) is the restored voltage waveform in the conventional coordinate system, and (d) is the restored voltage-current waveform in the relative coordinate system;

[0049] Figure 5 The method for classifying and discussing the voltage-current phase, where (a) is the voltage leading the current, (b) is the voltage lagging the current, (c) is the voltage lagging the current, and (d) is the voltage leading the current. Detailed implementation mode

[0050] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] The non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method of the present invention adopts a unique zero-crossing capture technology. By constructing a relative coordinate system that controls the zero position, it can accurately calculate the time difference between the moment when the current and voltage change from the low-level state to the high-level state and the zero position of the relative coordinate system. Based on this time difference, the phase difference between the current and voltage can be determined. The data processing steps of this method are mainly divided into four steps, including: testing capacitor charging and discharging and voltage amplitude measurement, microprocessor collecting current values, voltage phase measurement, and voltage-current waveform restoration. Among them, voltage amplitude measurement, voltage phase measurement, and voltage-current waveform restoration require the use of synchronous measurement methods to ensure the accuracy of measurement.

[0052] As Figure 1 shown, the non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method of the present invention includes the following steps:

[0053] S1. The energy-taking plate charges the test capacitor through the current-carrying conductor. When the voltage across the test capacitor reaches the discharge threshold voltage, record the charging time t, and calculate the voltage amplitude of the current-carrying conductor through the charging time t; the hysteresis comparison circuit outputs a high level, and the capacitor releases energy; establish a relative coordinate system with the moment when the hysteresis comparison circuit outputs a high level as the zero point;

[0054] As Figure 2 shown, the equivalent capacitance between the energy-taking plate and the current-carrying conductor is C1, the coupling capacitance between the energy-taking plate and the ground is C2, and the voltage of the current-carrying conductor is U p, take the voltage between the energy-taking electrode plate and the current-carrying conductor as U1, and take the voltage between the energy-taking electrode plate and the ground as U2. The full-bridge rectifier circuit is composed of high-reverse-resistance diodes. The energy obtained by the energy-taking electrode plate through the current-carrying conductor is rectified by the full-bridge rectifier circuit and then used to charge the test capacitor C. t When charging; use a hysteresis comparison circuit to monitor the voltage across the test capacitor. When the voltage across the test capacitor reaches the discharge threshold, the hysteresis comparator circuit outputs a 5V signal and a 3.3V step-down high-level signal; the 5V signal controls the silicon carbide MOSFET switch tube to conduct, and discharges the energy in the test capacitor C. t The sawtooth wave in the figure is the charge and discharge waveform of the test capacitor; the 3.3V step-down high level in the figure is transmitted to the microprocessor, and the coordinate system of its pulse waveform is a conventional coordinate system. t0, 2t0, and 3t0 are the time points when the hysteresis comparison circuit outputs a high level, which are used as the zero points of the relative coordinate system.

[0055] The voltage amplitude measurement adopts an inversion measurement method, and determines the magnitude of the current-carrying conductor voltage by monitoring the charging time of the test capacitor. The current-carrying conductor voltage U p The expression is: U p =(U ct -U0)C t / 0.9ωC2t, where U0 is the initial voltage of the test capacitor, C t is the capacitance value of the test capacitor, and ω is the power frequency angular frequency; C2 is the coupling capacitance between the energy-taking electrode plate and the ground corrected according to the inversion voltage error value; U ct is the discharge threshold voltage, and t is the charging time of the test capacitor voltage from U0 to U ct . Use a hysteresis comparison circuit to monitor the voltage across the test capacitor. When the voltage reaches the discharge threshold U ct , the hysteresis comparison circuit outputs a 5V signal and a 3.3V step-down high-level signal. The 5V signal controls the MOSFET switch tube to open and discharges the energy in the test capacitor C t . The 3.3V step-down high-level signal is transmitted to the microprocessor. When the test capacitor voltage reaches the discharge threshold voltage, it marks the end of the current test capacitor charging time and the start of the next cycle of the test capacitor charging time, and defines the time point when the hysteresis comparison circuit outputs a high level as the zero point t0 of the relative coordinate system for subsequent calculations. Specifically:

[0056] Under power frequency conditions, when the size and position of the energy-taking electrode plate are fixed, the value of the coupling capacitance C2 between the energy-taking electrode plate and the ground remains unchanged. At this time, the current-carrying conductor voltage U p is related to the displacement current I d , that is:

[0057]

[0058] Among them, ω is the power frequency angular frequency.

[0059] Therefore, the voltage U of the high-voltage current-carrying conductor can be realized by monitoring the magnitude of the displacement current I d to solve the inverse problem. By collecting the charging rate of the test capacitor C p to obtain the displacement current I t magnitude, so as to inversely deduce the voltage U of the high-voltage current-carrying conductor d , where t is the charging time for the test capacitor voltage to change from the initial value U0 to U p , and U ct is the discharge threshold voltage of the test capacitor. If the leakage current of the diode in the full-bridge rectifier circuit is ignored, the voltage U ct of the test capacitor after time t can be expressed as: ct can be expressed as:

[0060]

[0061] where ω is the power frequency angular frequency, C2 is the coupling capacitance between the energy-taking plate and the ground corrected according to the inversion voltage error value, and U0 is the initial value of the test capacitor voltage. Then the voltage U p of the current-carrying conductor can be expressed as:

[0062]

[0063] As can be seen from the above analysis, under power frequency conditions, when the size and position of the energy-taking plate are fixed, the value of the coupling capacitance C2 between the energy-taking plate and the ground remains unchanged. After selecting the test capacitor C t and the diodes of the full-bridge rectifier circuit, at this time, the voltage U p of the current-carrying conductor is related to the charging time t required for the test capacitor voltage to change from the initial value U0 to U ct . Since the charging time t basically does not change when the external conditions remain unchanged, the test capacitor is directly grounded, and the energy stored in it is discharged very quickly. After the test capacitor voltage reaches the discharge threshold voltage, the hysteresis comparison circuit outputs a high level, and establishing a relative coordinate system with this moment as the zero point can ensure the instantaneous effectiveness of synchronous voltage and current measurement.

[0064] S2. The microprocessor obtains several equally spaced real-time current values within a power frequency cycle, calculates the amplitude and phase of the current in the current-carrying conductor, and draws the current waveform;

[0065] In this embodiment, the restoration of the current waveform requires the assistance of the analog-to-digital converter (ADC) function of the microprocessor. When the microprocessor receives the 3.3V high-level signal output by the hysteresis comparison circuit, it immediately uses this signal as the starting point and starts continuous ADC value acquisition. The total acquisition duration is 20ms, covering a power frequency cycle, and 2 m(m≥3) points. Through the discrete data reduction method, the amplitude and phase of the current in the current-carrying conductor are calculated. The moment when the current changes from negative to positive is t1, and the time difference between this moment and the zero point of the constructed relative coordinate system is (t0 - t1).

[0066] Figure 2 The 3.3V buck high-level pulse signal input into the microprocessor is the trigger signal for real-time current value measurement. The microprocessor uses an analog-to-digital converter (ADC) to collect 2 m (m≥3) equally spaced instantaneous current points within one power frequency cycle, as shown in Figure 3 (a) in it. Through the discrete data reduction method, the amplitude and phase of the current in the current-carrying conductor are calculated and the current waveform of the current-carrying conductor is plotted, as shown in Figure 3 (b) in it.

[0067] The discrete data reduction method uses the full-wave Fourier algorithm. If the original analog signal is a periodic function, its Fourier series form is:

[0068]

[0069] where x(t) is the function of the current in the current-carrying conductor with respect to t, the angular frequency of the original analog signal is ω1, n = 0, 1, 2, … ∞, a n represents the amplitude of the non-sinusoidal part of the nth harmonic, b n represents the amplitude of the sinusoidal part of the nth harmonic. If n = 0, at this time a0 represents the DC component.

[0070] When n = 1, calculated according to the Fourier series, a1 and b1 can be calculated as:

[0071]

[0072] where the fundamental wave component contained in x(t) can be expressed in the time-frequency domain as:

[0073]

[0074] From Equation (6), the effective value X of the fundamental wave quantity and the initial phase θ0 can be calculated respectively as:

[0075]

[0076] When calculating a1 and b1 through the microprocessor, Equation (5) is usually obtained by using the finite-term method. By importing the sampled point data into x(t) and then replacing the integral with summation, a1 and b1 can be calculated:

[0077]

[0078] where x kis the actual value represented by the k-th real-time current sampling point, where k is the ordinal number of the real-time current sampling point, k = 0, 1, 2, …, N, and N is the number of real-time current value sampling points within a power frequency cycle, usually 2 m (m ≥ 3).

[0079] Similarly, when n is any value, a n and b n can be calculated as follows:

[0080]

[0081] S3. Convert the sinusoidal voltage waveform of the current-carrying conductor into a square wave. The microprocessor records the start time of the first complete high level of the square wave voltage of the current-carrying conductor and calculates the difference between this time and the time when the hysteresis comparison circuit outputs a high level signal;

[0082] Voltage phase measurement uses a voltage division and zero-crossing comparison processing method to divide the voltage of the current-carrying conductor and convert the voltage of the current-carrying conductor from a sine wave to a square wave. Timing is carried out after the microprocessor receives the 3.3V step-down high level signal output by the hysteresis comparison circuit. When the microprocessor receives the first complete high level signal of the square wave voltage of the current-carrying conductor, record the start time t2 of the first square wave voltage high level. This time is the generation time of the first complete low level of the voltage of the current-carrying conductor, and the time difference from the zero point of the relative coordinate system is (t2 - t0).

[0083] S4. According to the real-time value of the current in the current-carrying conductor, the amplitude of the voltage of the current-carrying conductor, and the difference between the start time of the first complete high level of the square wave voltage of the current-carrying conductor and the time when the hysteresis comparison circuit outputs a high level signal, restore the waveforms of the voltage and current of the current-carrying conductor to a relative coordinate system with the time when the hysteresis comparison circuit outputs a high level signal as the zero point, and calculate the phase difference between the voltage and current.

[0084] As Figure 4 shown, it describes the process of restoring the voltage and current waveforms to the relative coordinate system. Figure 4 In (a), it is a relative coordinate system constructed with the time t0 when the hysteresis comparison circuit outputs a high level as the relative zero point; Figure 4 In (b), it is the current waveform of the current-carrying conductor restored according to the collected real-time current data points. The coordinate system therein is the real-time conventional coordinate system, and t1 is the time when the current of the current-carrying conductor changes from negative to positive; Figure 4 In (c), it is the sinusoidal voltage waveform of the current-carrying conductor restored with the amplitude of the voltage of the current-carrying conductor obtained by formula (3) and the square wave voltage waveform of the current-carrying conductor obtained after voltage division and zero-crossing comparison processing. The coordinate system therein is the real-time conventional coordinate system, and t2 is the start time when the microprocessor obtains the first complete high level of the square wave voltage of the current-carrying conductor; Since Figure 4In (b) and (c), the coordinate system of the restored voltage and current waveforms of the current-carrying conductor is the conventional coordinate system, not the relative coordinate system. The phases of the restored voltage and current waveforms in the relative coordinate system are not 0. Therefore, if Figure 4 calculating the phase difference between the voltage and current waveforms of the current-carrying conductor in (b) and (c), further processing is required. By calculating the time difference (t0 - t1) between the moment t1 when the current changes from negative to positive and the zero point of the constructed relative coordinate system, the phase of the current-carrying conductor current can be obtained. By calculating the time difference (t2 - t0) between the start moment t2 when the microprocessor obtains the first complete high level of the square wave voltage of the current-carrying conductor and the zero point t0 of the relative coordinate system, the phase of the voltage of the current-carrying conductor can be obtained. Putting the voltage and current waveforms of the current-carrying conductor in the conventional coordinate system into the relative coordinate system, as Figure 4 shown in (d), finally, the phase difference between the current and voltage, that is, the power factor angle, can be obtained.

[0085] The zero-crossing capture method is used to restore the voltage and current waveforms. Its principle is to construct a relative coordinate system with artificially controlled zero point position, and determine the phase difference between the current and voltage by calculating the distance between the moment when the current waveform and voltage waveform change from low level to high level and the zero point position of the relative coordinate system.

[0086] According to this time point t2, combined with the known power frequency period T of the voltage, the voltage phase value θ2 can be calculated as follows:

[0087]

[0088] Since the first high level of the square wave voltage of the current-carrying conductor obtained by the microprocessor is not necessarily a complete high level, the relationship between the moment t1 when the current-carrying conductor current changes from negative to positive and the start moment t2 when the microprocessor receives the first complete high level signal of the square wave voltage of the current-carrying conductor is divided into four discussions. The phase of the current relative to the relative zero point is θ1, and the phase of the voltage relative to the relative zero point is θ2. The voltage leads the current and the square wave voltage of the current-carrying conductor is at a low level at the zero point position of the relative coordinate system, the voltage lags behind the current and the square wave voltage of the current-carrying conductor is at a low level at the zero point position of the relative coordinate system, the voltage leads the current and the square wave voltage of the current-carrying conductor is at a high level at the zero point position of the relative coordinate system, the voltage lags behind the current and the square wave voltage of the current-carrying conductor is at a high level at the zero point position of the relative coordinate system. The corresponding relationships between θ1 and θ2 are as follows:

[0089]

[0090] Such as Figure 5As shown in (a) to (d), the square wave in the figure is the waveform obtained after the voltage of the current-carrying conductor is divided and zero-crossing compared. The low-level part is the positive voltage of the current-carrying conductor, and the high-level part is the negative voltage of the current-carrying conductor. The black solid line part in the figure is the trigger signal received by the microprocessor, and the actual signal width is narrower than that shown in the figure. Figure 5 In (a), θ2 < π, θ1 + θ2 < π. In this case, the voltage leads the current by an angle of π - (θ1 + θ2). Figure 5 In (b), θ2 < π, θ1 + θ2 > π. In this case, the voltage lags behind the current by an angle of θ1 + θ2 - π. Figure 5 In (c), θ2 > π, θ1 + θ2 < 2π. In this case, the voltage lags behind the current by an angle of θ1 + θ2 - 2π. Figure 5 In (d), θ2 > π, θ1 + θ2 > 2π. In this case, the voltage leads the current by an angle of 2π - (θ1 + θ2). Figure 5 In the figure, t1 is the time obtained by converting the current phase through calculation, and t1 = θ1 * T, where T is the power frequency period.

[0091] The microprocessor is responsible for timing and corresponding data processing. To enhance the working stability of the system, a controllable switch is added to isolate the voltage amplitude measurement and voltage phase measurement. At the moment when the high-level signal output by the hysteresis comparison circuit is received, the microprocessor needs to complete the switching of the controllable switch state, clear the timing, and collect the first discrete current data by the ADC, so as to establish the zero point of the relative coordinate system for synchronous voltage and current measurement.

[0092] A self-powered synchronous voltage and current measurement trigger method of the present invention can solve problems such as poor data synchronization, high manufacturing cost, lack of a reliable external power source, and the need for power outage for installation compared with the traditional synchronous voltage and current measurement method. In application scenarios such as synchronous voltage and current measurement of high-voltage current-carrying conductors, this trigger method is simple and easier to implement, and has good economy and practicability.

Claims

1. A non-invasive self-powered voltage and current synchronous measurement data inversion processing method synergistic with a magnetic and electric field source, characterized in that The steps include: Take an energy storage electrode plate to charge a test capacitor through a current-carrying conductor. When the voltage across the test capacitor reaches the discharge threshold voltage, record the charging time t, and calculate the voltage amplitude of the current-carrying conductor based on the charging time t; the hysteresis comparison circuit outputs a high level, and the test capacitor releases energy; establish a relative coordinate system with the moment when the hysteresis comparison circuit outputs a high level as the zero point; The microprocessor obtains several equally spaced real-time current values within a power frequency cycle, calculates the amplitude and phase of the current in the current-carrying conductor, and plots the current waveform; Convert the sinusoidal voltage of the current-carrying conductor into a square wave, record the start moment of obtaining the complete high level of the first square wave voltage of the current-carrying conductor, and calculate the time difference between this moment and the moment when the hysteresis comparison circuit outputs a high level signal; According to the real-time value of the current in the current-carrying conductor, the voltage amplitude of the current-carrying conductor, and the time difference between the start moment of obtaining the complete high level of the first square wave voltage of the current-carrying conductor and the moment when the hysteresis comparison circuit outputs a high level signal, restore the waveforms of the voltage and current of the current-carrying conductor to the relative coordinate system with the moment when the hysteresis comparison circuit outputs a high level signal as the zero point, and calculate the voltage-current phase difference.

2. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method according to claim 1, wherein The voltage amplitude of the current-carrying conductor adopts an inversion measurement method, specifically: Among them, U p is the voltage of the current-carrying conductor, U ct is the charging voltage of the fixed test capacitor, U0 is the initial voltage of the test capacitor, C t is the capacitance value of the test capacitor, ω is the power frequency angular frequency, C2 is the coupling capacitance between the energy-taking plate and the ground corrected according to the inversion voltage error value, and t is the charging time for the test capacitor voltage to change from U0 to U ct .

3. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method according to claim 1, characterized in that The calculation method for the amplitude and phase of the current in the current-carrying conductor is: According to several equally spaced real-time current values obtained within a power frequency cycle, calculate the amplitude and phase of the current in the current-carrying conductor through the discrete data restoration method. The moment when the current changes from negative to positive is recorded as t1, and the time difference between it and the zero point of the constructed relative coordinate system is (t0 - t1).

4. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion and processing method according to claim 3, characterized in that The discrete data restoration method adopts the full-wave Fourier algorithm. If the original analog signal is a periodic function, its Fourier series form is: where x(t) is a function of the current of the current-carrying conductor with respect to t, the angular frequency of the original analog signal is ω1, n = 0, 1, 2, … ∞, a n represents the amplitude of the non-sinusoidal part of the nth harmonic, b n represents the amplitude of the sinusoidal part of the nth harmonic. If n = 0, a0 represents the DC component at this time; When n = 1, calculate according to the Fourier series, and calculate a1 and b1 as: Among them, the fundamental wave component contained in x(t) is expressed in the time-frequency domain as: Calculate the effective value X of the fundamental wave quantity and the initial phase θ0 respectively from the above formula: 2X 2 = a1 2 + b1 2 The calculation formulas for a1 and b1 are: where x k is the actual value represented by the k-th real-time current sampling point, k is the ordinal number of the real-time current sampling point, k = 0, 1, 2, …, N, and N is the number of real-time current value sampling points within a power frequency cycle; Similarly, when n is any value, calculate a n and b n :

5. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method according to claim 1, characterized in that When measuring the voltage phase, start timing after the microprocessor receives the 3.3V step-down high level signal. When the microprocessor receives the complete high level signal of the first square wave voltage of the current-carrying conductor, output the start moment t2 when the microprocessor receives the complete high level signal of the square wave voltage. This time is the generation time of the first complete low level of the voltage of the current-carrying conductor, and the time difference from the zero point of the relative coordinate system is (t2 - t0).

6. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion processing method according to claim 1, characterized in that After the voltage-current waveforms restored according to the amplitude and phase of the voltage and current are placed in the constructed relative coordinate system, for the phase difference between the two waveforms, further calculation and processing are required. Obtain the moment when the current changes from negative to positive as t1 through the data restoration method, obtain the current phase by calculating the time difference (t0 - t1) between it and the zero point of the constructed relative coordinate system, obtain the voltage phase by calculating the time difference (t2 - t0) between the start moment t2 when the microprocessor receives the complete high level signal of the first square wave voltage of the current-carrying conductor and the zero point t0 of the relative coordinate system, and finally obtain the phase difference between the current and voltage, that is, the power factor angle.

7. The non-invasive magnetic and electric field source collaborative self-powered voltage and current synchronous measurement data inversion and processing method according to claim 1, characterized in that The relationship between the moment t1 when the current changes from negative to positive and the moment t2 when the microprocessor receives the first complete high-level signal of the square-wave voltage of the current-carrying conductor includes four cases; The voltage leads the current and the voltage square wave is at a low level at the zero position of the relative coordinate system, the voltage lags behind the current and the voltage square wave is at a low level at the zero position of the relative coordinate system, the voltage leads the current and the voltage square wave is at a high level at the zero position of the relative coordinate system, the voltage lags behind the current and the voltage square wave is at a high level at the zero position of the relative coordinate system. The relationships between the phase θ1 of the current relative to the relative zero point and the phase θ2 of the voltage relative to the relative zero point are as follows:

8. A self-powered voltage and current synchronous measurement data inversion and processing system with non-invasive magnetic and electric field source collaboration, characterized in that It includes: A voltage amplitude calculation unit, which is used to take the energy storage plate to charge the test capacitor through the current-carrying conductor. When the voltage across the test capacitor reaches the discharge threshold voltage, the hysteresis comparison circuit outputs a high level; record the charging time t, establish a relative coordinate system with the moment t0 when the hysteresis comparison circuit outputs a high level as the zero point, and calculate the voltage amplitude of the current-carrying conductor through the charging time t; A current waveform plotting unit, which is used for the microprocessor of the current waveform to obtain several equally spaced real-time current values within a power frequency cycle, calculate the amplitude and phase of the current of the current-carrying conductor, and plot the current waveform; A time difference calculation unit, which is used to convert the sinusoidal voltage of the current-carrying conductor into a square wave, record the start moment of obtaining the first complete high-level signal of the square-wave voltage of the current-carrying conductor and calculate the difference between this moment and the moment when the hysteresis comparison circuit outputs a high-level signal; A voltage-current phase difference calculation unit, which is used to restore the waveforms of the voltage and current of the current-carrying conductor to the relative coordinate system with the moment when the hysteresis comparison circuit outputs a high-level signal as the zero point according to the real-time value of the current of the current-carrying conductor, the voltage amplitude of the current-carrying conductor, and the difference between the start moment of obtaining the first complete high-level signal of the square-wave voltage of the current-carrying conductor and the moment when the hysteresis comparison circuit outputs a high-level signal, and calculate the voltage-current phase difference.

9. An electronic device, characterized in that, It includes a memory, a processor, and a computer program / instructions stored on the memory and executable on the processor. It is characterized in that when the computer program / instructions are executed by the processor, the steps of the non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method according to any one of claims 1-7 are realized.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, which are used to execute the steps of the non-invasive magnetic electric field source collaborative self-powered voltage-current synchronous measurement data inversion processing method according to any one of claims 1-7 when the computer instructions are called.

Images