Standard electronic transformer angular difference traceability device and method based on square waves

Abstract

The invention provides a standard electronic transformer angular difference traceability device and method based on square waves, and belongs to the technical field of power system measurement. And the delay phase determination module is used for determining a fundamental wave delay phase corresponding to the square wave voltage signal according to the rising time or falling time of the square wave voltage signal. And the standard analog-to-digital conversion mutual inductance module is used for carrying out filtering and analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal. And the calibration angle difference determination module is used for carrying out discrete Fourier transform on the digital voltage signal to obtain a fundamental wave phase corresponding to the digital voltage signal, and carrying out angle difference tracing on the detected electronic transformer according to a calibration angle difference obtained by calculating the fundamental wave phase and a fundamental wave delay phase. Through the device and the method provided by the invention, the calibration angular difference of the standard analog-to-digital conversion mutual inductance module can be accurately obtained, the tested electronic transformer is traced, the accuracy of angular difference traceability is improved, and the problem of low accuracy is solved.

Description

Technical Field

[0001] The present application belongs to the field of power system measurement technology, and in particular relates to a standard electronic transformer angle difference tracing device and method based on square waves. Background Art

[0002] An electronic instrument transformer (ETT) is a device used to measure current and voltage in power systems. In an EIT, phase error refers to the phase difference between the primary input signal and the secondary output signal. EITs (or analog input merging units) are calibrated using an EIT calibrator, which is calibrated using a standard EIT. Traceability of the phase error of a standard EIT is crucial for EIT traceability.

[0003] By tracing the angular difference of electronic transformers, it is possible to link the measurement results of the transformer angular difference to national or internationally recognized measurement standards. However, traditional technologies, limited by the limitations and uncertainties of the equipment themselves, have resulted in low accuracy in angular difference traceability. Summary of the Invention

[0004] The purpose of this application is to provide a standard electronic transformer angle difference tracing device and method based on square waves, aiming to solve the problem of low accuracy in traditional technologies.

[0005] The present application provides a standard electronic transformer angle difference tracing device based on square waves, comprising: A signal generation module, used for generating a square wave voltage signal and a clock synchronization signal; a delay phase determination module, connected to the signal generation module, for determining a fundamental wave delay phase corresponding to the square wave voltage signal according to a rise time or a fall time of the square wave voltage signal; A standard analog-to-digital conversion mutual inductance module is connected to the signal generation module and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal; A calibration angle difference determination module is connected to the standard analog-to-digital conversion mutual inductance module and the delayed phase determination module, and is used to perform discrete Fourier transform on the digital voltage signal to obtain the fundamental phase corresponding to the digital voltage signal, and to trace the angle difference of the electronic mutual inductor under test based on the calibration angle difference calculated based on the fundamental phase and the fundamental delayed phase.

[0006] In one embodiment, the signal generation module includes: a signal processing module, configured to generate a switch control signal and the clock synchronization signal, the signal processing module being connected to the standard analog-to-digital conversion mutual inductance module and configured to send the clock synchronization signal to the standard analog-to-digital conversion mutual inductance module; wherein the switch control signal is synchronized with the clock synchronization signal; A voltage generation module, used for generating positive voltage signals and negative voltage signals; The analog switch module is connected to the signal processing module and the voltage generating module respectively, and is used to switch and output the positive voltage signal and the negative voltage signal according to the switch control signal to form the square wave voltage signal.

[0007] In one embodiment, the signal generation module further includes: The first operational amplifier module is connected to the analog switch module and the standard analog-to-digital conversion mutual inductance module, and is used to amplify the positive voltage signal and the negative voltage signal, and output the square wave voltage signal to the standard analog-to-digital conversion mutual inductance module.

[0008] In one embodiment, the standard analog-to-digital conversion mutual inductance module includes: The analog-to-digital conversion sampling module is connected to the first operational amplifier module and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal to obtain a digital sampling signal.

[0009] In one embodiment, the standard analog-to-digital conversion mutual inductance module further includes: A protocol conversion control module is connected to the signal processing module and the analog-to-digital conversion sampling module, and is used to control the analog-to-digital conversion sampling module to perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal, and to perform protocol conversion on the digital sampling signal to obtain the digital voltage signal, and send it to the calibration angle difference determination module in the form of message data.

[0010] In one embodiment, the delay phase determination module is connected to the first operational amplifier module and is configured to determine the fundamental wave delay phase corresponding to the square wave voltage signal according to the rise time of the square wave voltage signal.

[0011] In one embodiment, the voltage generating module includes: A positive voltage generating module, configured to output the positive voltage signal; The positive voltage generating module is connected to the analog switch module and is configured to send the positive voltage signal to the analog switch module.

[0012] In one embodiment, the voltage generating module further includes: a first resistance module, one end of the first resistance module being connected to the positive voltage generating module; a second operational amplifier module, wherein an inverting input terminal of the second operational amplifier module is connected to the other end of the first resistor module, a non-inverting input terminal of the second operational amplifier module is grounded, and an output terminal of the second operational amplifier module is connected to the analog switch module, for sending the negative voltage signal to the analog switch module; A second resistance module, one end of the second resistance module is connected to the other end of the first resistance module, and the other end of the second resistance module is connected to the output end of the second operational amplifier module.

[0013] The present application provides a standard electronic transformer angle difference tracing method based on square waves, comprising: Sending square wave voltage signal and clock synchronization signal through signal generation module; The square wave voltage signal is received by a delay phase determination module, and a fundamental wave delay phase corresponding to the square wave voltage signal is determined according to a rise time or a fall time of the square wave voltage signal; The clock synchronization signal is received through a standard analog-to-digital conversion mutual inductance module, and the square wave voltage signal is sampled by analog-to-digital conversion according to the clock synchronization signal to obtain a digital voltage signal; The digital voltage signal is subjected to a discrete Fourier transform to obtain a fundamental phase corresponding to the digital voltage signal, and the angle difference of the electronic transformer under test is traced based on a calibration angle difference obtained by calculating the fundamental phase and the fundamental delayed phase.

[0014] In one embodiment, the step of tracing the angle difference of the electronic transformer under test based on the calibration angle difference calculated from the fundamental wave phase and the fundamental wave delayed phase includes: Obtaining a measured angle difference obtained by the electronic transformer under test measuring an input signal; The actual angular difference of the electronic transformer under test is determined according to the measured angular difference and the calibrated angular difference.

[0015] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: The standard electronic transformer angle difference tracing device based on square waves provided by the present application achieves starting position synchronization through the square wave voltage signal and clock synchronization signal generated by the signal generation module, and can achieve time synchronization between the standard analog-to-digital conversion mutual inductance module and the signal generation module, ensuring the accuracy of subsequent signal data transmission. By determining the delay phase corresponding to the fundamental wave signal during the square wave voltage signal transmission process through the delay phase determination module, the delay phase existing before the input to the standard analog-to-digital conversion mutual inductance module can be known, and the delay corresponding to the analog quantity can be determined.

[0016] Under the control of a clock synchronization signal, a square wave voltage signal passes through the standard A / D conversion mutual inductance module and outputs a digital voltage signal. The calibrated angular difference of the standard A / D conversion mutual inductance module can be accurately determined based on the fundamental phase of the digital voltage signal and the fundamental delay phase before input into the module. This calibrated angular difference serves as a key reference for traceability, serving as a basis for calibration and error correction, enabling accurate angular difference traceability of the electronic transformer under test (e.g., an electronic transformer calibrator).

[0017] Therefore, compared with traditional technologies, the square wave-based standard electronic transformer angle difference tracing device provided in this application calibrates the standard analog-to-digital conversion mutual inductance module according to the calibration angle difference obtained by calculating the fundamental wave phase and the fundamental wave delayed phase. The standard analog-to-digital conversion mutual inductance module can be used as a standard electronic transformer to trace the electronic transformer under test (such as an electronic transformer calibrator or other transformer that needs to be calibrated), thereby improving the accuracy of angle difference tracing and having high traceability, which helps to maintain the long-term stability of the measuring equipment during actual application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or exemplary technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic structural diagram of a standard electronic transformer angle difference tracing device based on square waves in some embodiments provided in this application.

[0020] Figure 2 This is a schematic structural diagram of the signal generation module in some embodiments provided in this application.

[0021] Figure 3 This is a schematic diagram comparing the voltage signal under an ideal state and the square wave voltage signal under an actual state in some embodiments provided in this application.

[0022] Figure 4 Schematic diagram of the waveform of the pulse per second (PPS) clock synchronization signal in some embodiments provided in this application.

[0023] Figure 5 This is a schematic structural diagram of a standard analog-to-digital conversion mutual inductance module in some embodiments provided in this application.

[0024] Figure 6These are the frequency spectrum characteristics inside the analog-to-digital conversion sampling module in some embodiments provided in this application.

[0025] Figure 7 This is a schematic flow chart of the steps of a standard electronic transformer angle difference tracing method based on square waves in some embodiments provided in this application. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0027] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0028] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0030] See Figure 1 The present application provides a standard electronic transformer angle difference tracing device 100 based on square waves. The standard electronic transformer angle difference tracing device 100 based on square waves includes a signal generating module 10, a delay phase determining module 20, a standard analog-to-digital conversion mutual inductance module 30, and a calibration angle difference determining module 40. The signal generating module 10 is used to generate a square wave voltage signal and a clock synchronization signal. The delay phase determining module 20 is connected to the signal generating module 10, and is used to determine the fundamental wave delay phase corresponding to the square wave voltage signal according to the rise time or fall time of the square wave voltage signal.

[0031] The standard analog-to-digital conversion mutual inductance module 30 is connected to the signal generation module 10 and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal. The calibration angle difference determination module 40 is connected to the standard analog-to-digital conversion mutual inductance module 30 and the delay phase determination module 20 and is used to perform a discrete Fourier transform on the digital voltage signal to obtain the fundamental phase corresponding to the digital voltage signal. Based on the calibration angle difference calculated from the fundamental phase and the fundamental delay phase, the angle difference is traced to the source of the electronic transformer under test.

[0032] In this embodiment, the square wave voltage signal and clock synchronization signal generated by the signal generation module 10 are used to calibrate the standard analog-to-digital conversion mutual inductance module 30. The clock synchronization signal is used to achieve time synchronization between the standard analog-to-digital conversion mutual inductance module 30 and the signal generation module 10. The clock synchronization signal and square wave voltage signal are input into the standard analog-to-digital conversion mutual inductance module 30.

[0033] The square wave voltage signal serves as the analog input signal for the standard analog-to-digital conversion mutual inductance module 30. After acquiring the square wave voltage signal, the delay phase determination module 20 analyzes the rise time or fall time of the square wave voltage signal to determine the fundamental delay phase corresponding to the square wave voltage signal. The fundamental delay phase can be understood as the delay phase existing before input into the standard analog-to-digital conversion mutual inductance module 30. Under the control of the clock synchronization signal, the standard analog-to-digital conversion mutual inductance module 30 filters and performs analog-to-digital conversion sampling on the square wave voltage signal to obtain the corresponding digital voltage signal. The digital voltage signal serves as the digital output signal of the standard analog-to-digital conversion mutual inductance module 30.

[0034] The calibration angle difference determination module 40 performs a discrete Fourier transform (DFT) on the digital voltage signal to obtain the fundamental phase corresponding to the digital voltage signal. Furthermore, the calibration angle difference of the standard analog-to-digital conversion mutual inductance module 30, calculated based on the fundamental phase and the fundamental delay phase, establishes the phase relationship between the analog and digital quantities.

[0035] The calibration angle difference determination module 40 calculates the calibration angle difference between the fundamental phase corresponding to the digital voltage signal output by the standard analog-to-digital conversion mutual inductance module 30 and the fundamental delayed phase corresponding to the square wave voltage signal input to the standard analog-to-digital conversion mutual inductance module 30. This is the angular difference between the input and output sides of the standard analog-to-digital conversion mutual inductance module 30. This calibration angle difference enables calibration of the standard analog-to-digital conversion mutual inductance module 30. Furthermore, based on the calibration angle difference of the standard analog-to-digital conversion mutual inductance module 30, the angular difference of the electronic mutual inductor under test can be traced.

[0036] The standard electronic transformer angle difference tracing device 100 based on square waves provided in this application achieves starting position synchronization through the square wave voltage signal and clock synchronization signal generated by the signal generation module 10, and can achieve time synchronization between the standard analog-to-digital conversion mutual inductance module 30 and the signal generation module 10, ensuring the accuracy of subsequent signal data transmission. By determining the delay phase corresponding to the fundamental wave signal during the square wave voltage signal transmission process through the delay phase determination module 20, the delay phase existing before the input to the standard analog-to-digital conversion mutual inductance module 30 can be determined, and the delay corresponding to the analog quantity can be determined.

[0037] Under the control of a clock synchronization signal, the square wave voltage signal passes through the standard analog-to-digital conversion mutual inductance module 30, and then outputs a digital voltage signal. Based on the fundamental wave phase corresponding to the digital voltage signal and the fundamental wave delay phase existing before input into the standard analog-to-digital conversion mutual inductance module 30, the calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30 can be accurately obtained. The calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30, a key reference for traceability, serves as a basis for calibration and error correction, and accurately traces the angular difference of the electronic transformer under test (e.g., a transformer requiring calibration, such as an electronic transformer calibrator).

[0038] Therefore, compared with traditional technologies, the square wave-based standard electronic transformer angle difference tracing device 100 provided in the present application calibrates the standard analog-to-digital conversion mutual inductance module 30 according to the calibration angle difference obtained by calculating the fundamental wave phase and the fundamental wave delayed phase. The standard analog-to-digital conversion mutual inductance module 30 can be used as a standard electronic transformer for traceability calibration of the electronic transformer under test (such as an electronic transformer calibrator or other transformer that needs to be calibrated), thereby improving the accuracy of angle difference traceability, having high traceability, and helping to maintain the long-term stability of the measuring equipment during actual application.

[0039] See Figure 2 In one embodiment, the signal generation module 10 includes a signal processing module 110, a voltage generation module 120, and an analog switch module 130. The signal processing module 110 is used to generate a switch control signal and a clock synchronization signal. The signal processing module 110 is connected to the standard analog-to-digital conversion mutual inductance module 30 and is used to send the clock synchronization signal to the standard analog-to-digital conversion mutual inductance module 30. The switch control signal is synchronized with the clock synchronization signal. The voltage generation module 120 is used to generate a positive voltage signal and a negative voltage signal. The analog switch module 130 is connected to the signal processing module 110 and the voltage generation module 120 respectively, and is used to switch the output of the positive voltage signal and the negative voltage signal according to the switch control signal.

[0040] In this embodiment, the switch control signal generated by the signal processing module 110 is synchronized with the starting position of the clock synchronization signal. The switch control signal controls the analog switch module 130 to switch the output order of the positive and negative voltage signals, thereby obtaining highly stable positive and negative voltage signals and forming a highly stable square wave signal. The two output terminals of the voltage generation module 120 can output positive and negative voltage signals to the S1 and S2 terminals of the analog switch module 130. The switch control signal is input to the A0 terminal of the analog switch module 130.

[0041] Under the control of the switch control signal, the analog switch module 130 is controlled to switch the output positive voltage signal and the negative voltage signal to form a square wave voltage signal in which the positive voltage signal and the negative voltage signal intersect. The analog switch module 130 has the advantages of low on-resistance, low charge injection, low off capacitance and multi-channel multiplexing, and can perform well in data acquisition and sample-and-hold applications where low glitches and fast settling time are required. Furthermore, the analog switch module 130 can switch the output positive voltage signal and the negative voltage signal at high speed under the control of the switch control signal, so that the delay time of the signal generating module 10 itself is reduced, so as to form a square wave voltage signal at high speed, which is beneficial to improving the accuracy of the standard electronic transformer angle difference tracing device 100 based on square waves.

[0042] In one embodiment, the clock synchronization signal is a pulse per second (PPS) pulse synchronization signal, which generates a precise pulse signal per second to achieve time synchronization between different modules.

[0043] In one embodiment, the signal processing module 110 can be a high-performance dual-core fixed-point digital signal processor such as the ADSP-BF609, which integrates multiple peripherals and multiple timers and / or counters, supports pulse-width modulation (PWM) functionality, and can meet the needs of various applications. A timer in the signal processing module 110 has a period of 20 ms and a pulse width of 10 ms, and is used to form a switch control signal to assist in the subsequent formation of positive and negative voltage signals. Another timer in the signal processing module 110 has a period of 1 s and a pulse width of 10 ms, and is used to form a clock synchronization signal. The starting position of the clock synchronization signal is synchronized with the starting position of the switch control signal, and the initial moment of the clock synchronization signal corresponds to the initial position of the square wave voltage signal.

[0044] In one embodiment, the analog switch module 130 may be ADG1208, which has a switching time of no more than 125ns, and can meet the requirements for fast signal switching in high-speed application scenarios, ensuring accurate selection and transmission of the required analog signal in a short time, thereby improving work efficiency and signal processing speed.

[0045] In one embodiment, the signal generation module 10 further includes a first operational amplifier module 140. The first operational amplifier module 140 is connected to the analog switch module 130 and the standard analog-to-digital conversion mutual inductance module 30, and is configured to amplify the positive voltage signal and the negative voltage signal and output a square wave voltage signal to the standard analog-to-digital conversion mutual inductance module 30.

[0046] In this embodiment, the switch control signal is used to control the analog switch module 130 to switch the output order of the positive voltage signal and the negative voltage signal. The first operational amplifier module 140 amplifies the positive and negative voltage signals to form square wave voltage signals. The square wave voltage signals are output to the standard analog-to-digital conversion mutual inductance module 30. By amplifying the positive and negative voltage signals by the first operational amplifier module 140, square wave voltage signals of different amplitudes can be obtained, which are compatible with the standard analog-to-digital conversion mutual inductance module 30.

[0047] In one embodiment, the first operational amplifier module 140 may be an ADA4807-1, a high-performance amplifier with low power consumption, low noise, high speed, and DC precision. With a gain of +1 and a peak-to-peak output voltage of 20 mV, the first operational amplifier module 140 has a −3dB bandwidth of up to 180 MHz, a slew rate of 225 V / μs, and a settling time to 0.1% of 47 ns (4 V step).

[0048] In one embodiment, the voltage generation module 120 includes a positive voltage generation module 121. The positive voltage generation module 121 is configured to output a positive voltage signal and is connected to the analog switch module 130 to send the positive voltage signal to the analog switch module 130.

[0049] In this embodiment, the positive voltage generation module 121 is connected to the S1 port of the analog switch module 130 and is used to send a positive voltage signal to the analog switch module 130. Furthermore, the analog switch module 130 outputs the positive voltage signal and the negative voltage signal alternately based on the control sequence of the switch control signal to form a square wave voltage signal.

[0050] In one embodiment, the positive voltage generation module 121 can be EVAL-ADR1001, which has the characteristics of high precision, high stability and low noise, and provides a stable reference voltage to ensure the accuracy of the voltage signals converted in subsequent modules, so as to help reduce the error of the entire device.

[0051] In one embodiment, the positive voltage signal output by the positive voltage generation module 121 can be a voltage of different amplitudes such as 5V, with an excellent peak-to-peak (Vp-p) noise of 1.2μ. The noise level is low, which helps to maintain the integrity of the positive voltage signal, making the positive voltage signal more stable and pure, and ensuring the accuracy and reliability of the positive voltage signal during transmission and processing.

[0052] In one embodiment, the voltage generation module 120 further includes a first resistor module 122, a second operational amplifier module 123, and a second resistor module 124. One end of the first resistor module 122 is connected to the positive voltage generation module 121. The inverting input end of the second operational amplifier module 123 is connected to the other end of the first resistor module 122.

[0053] The non-inverting input terminal of the second operational amplifier module 123 is grounded. The output terminal of the second operational amplifier module 123 is connected to the analog switch module 130 for sending a negative voltage signal to the analog switch module 130. One end of the second resistor module 124 is connected to the other end of the first resistor module 122. The other end of the second resistor module 124 is connected to the output terminal of the second operational amplifier module 123.

[0054] In this embodiment, the first resistor module 122, the second operational amplifier module 123, and the second resistor module 124 form an inverting proportional amplifier module. A positive voltage signal input to the inverting input terminal of the second operational amplifier module 123 is processed by the second operational amplifier module 123 to output a negative voltage signal. The positive voltage signal is opposite to the negative voltage signal, achieving inverting amplification of the signal. The resistance values ​​of the first resistor module 122 and the second resistor module 124 are equal, and thus the first resistor module 122, the second operational amplifier module 123, and the second resistor module 124 form an inverting proportional amplifier module of equal proportions, so that the negative voltage signal and the positive voltage signal have opposite phases and equal magnitudes, thereby forming a square wave voltage signal.

[0055] In one embodiment, the second operational amplifier module 123 utilizes the low-offset ADA4522, which features high-precision amplification, low noise performance, high gain-bandwidth product, and slew rate. The typical offset voltage of the ADA4522 is 1.5 μV. Both the first resistor module 122 and the second resistor module 124 include at least one resistor. These resistors are precision resistors with a 1 ppm rating.

[0056] In one embodiment, the delay phase determination module 20 is connected to the first operational amplifier module 140 and is configured to determine the fundamental wave delay phase corresponding to the square wave voltage signal according to the rise time of the square wave voltage signal.

[0057] In this embodiment, for ease of understanding, the Fourier series corresponding to the square wave voltage signal can be expressed as: .

[0058] in, k is an odd number, A is the amplitude, and ω is the angular velocity.

[0059] It can be seen from the above formula that the initial phase of the fundamental signal corresponding to the square wave voltage signal and the initial phase of each odd harmonic signal correspond to the starting position of the square wave voltage signal.

[0060] The synchronization relationship between the two signals is determined by the rising edge of the clock synchronization signal and the square wave voltage signal, thereby determining the phase relationship between the square wave voltage signal before entering the standard analog-to-digital conversion mutual inductance module 30 and the digital voltage signal after outputting the standard analog-to-digital conversion mutual inductance module 30 during the signal transmission process.

[0061] Since the analog switch module 130 and the first operational amplifier module 140 have a slew rate, it can also be understood that the rising edge or falling edge of the square wave voltage signal in the actual state cannot achieve 0 seconds to rise and 0 seconds to fall, and there will be a rising and falling time, such as Figure 3 shown. Figure 3 Waveform a in the middle represents the voltage waveform of 0 second rise and 0 second fall under the ideal state, and waveform b represents the square wave voltage signal under the actual state.

[0062] Furthermore, for ease of understanding, Figure 3 As shown, the Fourier series corresponding to the square wave voltage signal in the actual state can be expressed as: .

[0063] in, k is an odd number, A is the amplitude, and ω is the angular velocity.

[0064] When the delay time td (which can also be understood as the rise or fall time td) is close to 0, the Fourier series formula corresponding to the square wave voltage signal in the actual state is: .

[0065] The formula of the Fourier series corresponding to the square wave voltage signal in the actual state is identical to the formula of the Fourier series corresponding to the square wave voltage signal.

[0066] Furthermore, according to the formula of the Fourier series corresponding to the square wave voltage signal in the actual state and the formula of the Fourier series corresponding to the square wave voltage signal, it can be known that the fundamental phase of the square wave voltage signal in the actual state is consistent with the fundamental phase of the square wave voltage signal.

[0067] Therefore, the delay time corresponding to the square wave voltage signal from 0 to the actual positive state is td / 2, which can be converted into the corresponding fundamental wave delay phase and can be expressed as: .

[0068] The square wave voltage signal with the fundamental wave delayed phase is input into the standard analog-to-digital conversion mutual inductance module 30. The fundamental wave delayed phase in this embodiment can be used to determine the delayed phase of the input signal before entering the standard analog-to-digital conversion mutual inductance module 30, thereby facilitating the subsequent calibration of the angular difference of the standard analog-to-digital conversion mutual inductance module 30.

[0069] In one embodiment, due to the high speed of the analog switch module 130 and the first operational amplifier module 140, the actual delay time td (which can also be understood as the rise or fall time td) is less than 100 ns, and the delay td / 2 is less than 50 ns. The fundamental wave delay phase corresponding to the square wave voltage signal is: .

[0070] Thus, the square wave voltage signal can establish a synchronization signal relative to the PPS pulse per second signal (such as Figure 4 The phase of the clock synchronization signal (as shown) is a fundamental wave delay phase of -0.054 minutes.

[0071] In one embodiment, the delay phase determination module 20 includes an oscilloscope.

[0072] In one embodiment, the standard analog-to-digital conversion mutual inductance module 30 can be used as a standard electronic mutual inductor for analog-to-digital conversion based on sigma-delta or an analog input merging unit.

[0073] See Figure 5 In one embodiment, the standard analog-to-digital conversion mutual inductance module 30 includes an analog-to-digital conversion sampling module 310. The analog-to-digital conversion sampling module 310 is connected to the first operational amplifier module 140 and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal to obtain a digital sampling signal.

[0074] In this embodiment, the square wave voltage signal is filtered by the analog-to-digital conversion sampling module 310, which can solve the spectrum aliasing problem caused by the infinite spectrum of the square wave voltage signal, thereby improving the accuracy of the fundamental wave measurement. Figure 6 It can be seen that for values ​​greater than 0.5f IN Input signal frequency / f DATA The sampling rate frequency is attenuated by approximately 110dB, which translates to an accuracy level of 2.8ppm, thereby improving the accuracy of the entire device. After filtering by the analog-to-digital conversion sampling module 310, the frequency components with extremely small amplitudes can be ignored after passing through the filter.

[0075] The ADC Sampling Module 310 integrates the ADS1278 high-performance sigma-delta development board and features a built-in 24-bit, 8-channel, simultaneous sampling delta-sigma ADC. The ADC Sampling Module 310 implements delta-sigma modulation technology, and combined with a low-noise front-end design, achieves extremely low noise levels. Combining high-precision industrial measurements with excellent DC and AC specifications, the ADC Sampling Module 310 provides a usable signal bandwidth of up to 90% of the Nyquist rate.

[0076] The square wave-based standard electronic transformer angle difference tracing device 100 utilizes the phase-in-phase characteristic of the fundamental signal inherent in the square wave voltage signal and the internal anti-aliasing filter of the sigma-delta-based analog-to-digital conversion ADS1278 to construct an analog-to-digital synchronous sampling system, which directly associates the analog and digital quantities through the clock synchronization signal.

[0077] In one embodiment, the standard analog-to-digital conversion mutual inductance module 30 further includes a protocol conversion control module 320. The protocol conversion control module 320 is connected to the signal processing module 110 and the analog-to-digital conversion sampling module 310, and is configured to control the analog-to-digital conversion sampling module 310 to perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal, and perform protocol conversion on the digital sampled signal to obtain a digital voltage signal, and send the digital voltage signal to the calibration angle difference determination module 40 in the form of message data.

[0078] In this embodiment, protocol conversion control module 320, under the control of a clock synchronization signal, continuously controls analog-to-digital conversion sampling module 310 to collect square wave voltage signals. Furthermore, protocol conversion control module 320 performs protocol conversion on the digital sampled signal, converting it into a digital voltage signal compliant with the IEC 61850-9-2 standard. This signal is then sent as message data to calibration angle difference determination module 40 for analysis and processing.

[0079] In one embodiment, 1V of the digital sampling signal corresponds to 10kV in the IEC61850-9-2 standard, which can reduce quantization errors. The voltage conversion relationship can also be configured according to actual needs. The protocol conversion control module 320 sets the packet number corresponding to the message data to 0 based on the synchronization time of the clock synchronization signal, which serves as the starting position of the digital voltage signal of the digital quantity.

[0080] In one embodiment, the protocol conversion control module 320 is connected to the analog-to-digital conversion sampling module 310 via a serial peripheral interface (SPI) to read the sampled data of the analog-to-digital conversion and obtain a digital sampling signal.

[0081] In one embodiment, the protocol conversion control module 320 may be an ADSP-BF609_ezkit, which integrates peripherals such as Ethernet, SPI interface, timer, power supply, and reference.

[0082] The square wave-based standard electronic transformer angle difference tracing device 100 provided in the present application does not require expensive equipment or high-precision foreign instruments such as 3458A, thereby reducing the cost of angle difference tracing.

[0083] See Figure 7 The present application provides a square wave-based standard electronic transformer angle difference tracing method, which uses a square wave-based standard electronic transformer angle difference tracing device 100. The square wave-based standard electronic transformer angle difference tracing method includes: Step S10, sending a square wave voltage signal and a clock synchronization signal through the signal generation module 10; Step S20, receiving the square wave voltage signal through the delay phase determination module 20, and determining the fundamental wave delay phase corresponding to the square wave voltage signal according to the rise time or fall time of the square wave voltage signal; Step S30, receiving the clock synchronization signal through the standard analog-to-digital conversion mutual inductance module 30, and performing analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal; Step S40: performing discrete Fourier transform on the digital voltage signal to obtain the fundamental phase corresponding to the digital voltage signal, and tracing the angle difference of the electronic transformer under test based on the calibration angle difference calculated from the fundamental phase and the fundamental delayed phase.

[0084] In this embodiment, the description of step S10 can refer to the description of the above embodiment. The description of step S20 can refer to the description of the above embodiment. The description of step S30 can refer to the description of the above embodiment. The description of step S40 can refer to the description of the above embodiment.

[0085] In one embodiment, the signal generation module 10 outputs a 50 Hz square wave voltage signal and a clock synchronization signal (e.g., a clock synchronization PPS signal). The rising edges of the square wave voltage signal and the clock synchronization signal are aligned. The clock synchronization signal is a signal output by a timer controlled by the signal processing module 110 within the signal generation module 10 and can be accurate to 10 nanoseconds. Furthermore, the output timing of the square wave voltage signal and the clock synchronization signal from the signal generation module 10 can be accurate to 10 nanoseconds.

[0086] The rise time or fall time td of the square wave voltage signal is measured by the delay phase determination module 20. The delay time corresponding to the square wave voltage signal from 0 to the actual positive state is td / 2, which can be converted into the corresponding fundamental wave delay phase. Wherein, the value of td is 100ns, the delay of td / 2 is 50ns, and the fundamental wave delay phase is: .

[0087] The fundamental wave delay phase is -0.054 minutes, which can also be understood as the phase error of the delay caused by the slew rate of the analog switch module 130 and the first operational amplifier module 140 is -0.054 minutes.

[0088] Under the control of a clock synchronization signal (e.g., a clock synchronization PPS signal), the standard analog-to-digital conversion mutual inductance module 30 continuously performs filtering and analog-to-digital conversion sampling at a sampling rate of 4k Samples Per Second (4kSPS), and converts the sampled digital sampling signal into data that complies with the IEC61850-9-2 protocol.

[0089] In one embodiment, the calibration angle difference determination module 40 can be IEC61850-9-2 protocol analysis software, which performs discrete Fourier transform on the digital voltage signal and calculates the fundamental phase corresponding to the digital voltage signal. φ 2. In one embodiment, the IEC 61850-9-2 protocol analysis software is a set of software running on a computer with an RJ45 Ethernet port.

[0090] According to the fundamental phase φ 2 and fundamental wave delay phase φ 1 Calculate and obtain the calibration angle difference of the standard analog-to-digital conversion mutual inductance module 30 φ , which can be expressed as: φ=φ 2- φ 1.

[0091] The calibration angle difference is the phase converted from the delay of the analog quantity to the digital quantity of the standard analog-to-digital conversion mutual inductance module 30, which can be used as a calibration value.

[0092] Among them, the calibration angle difference φ In the formula, the fundamental wave delay phase φ 1 is a negative value, which can be understood as the phase shift caused by the delay of the rise time (also known as the rising edge time) or the fall time (also known as the falling edge time) of the square wave voltage signal. The fundamental phase corresponding to the digital voltage signal φ 2 is a negative value, which can be understood as the phase shift formed by the delay of the sampling process (AD sampling) in analog-to-digital conversion plus the delay of the rise time (or fall time) of the square wave voltage signal.

[0093] By calculating the calibration angle difference of the standard analog-to-digital conversion mutual inductance module 30 φ The square wave voltage signal is used to calibrate the angular difference of the standard analog-to-digital conversion mutual inductance module 30. The calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30 serves as a key reference for calibration, as well as a basis for error correction, to achieve angular difference traceability.

[0094] Thus, through the square wave-based standard electronic transformer angle difference traceability device 100 and the square wave-based standard electronic transformer angle difference traceability method provided by the present application, by comparing the square wave voltage signal with the clock synchronization signal through an oscilloscope, the value of the delay time td can be determined to be 100ns, which can be traced back to the national measurement benchmark or internationally recognized measurement standard. The delay time corresponding to the square wave voltage signal in the actual state from 0 to positive is td / 2=50ns, and the corresponding fundamental wave delay phase is -0.054 minutes, which is converted to the accuracy level of 15ppm in the national measurement standard, which is better than the domestic 0.01% electronic transformer calibration device and the European 30ppm power management unit (Power Management Unit, PMU) calibration device. It can calibrate electronic transformer calibrators of level 0.01 and below, and achieve an electronic transformer calibrator angle difference value transfer accuracy better than 20ppm.

[0095] Furthermore, through the square wave-based standard electronic transformer angle difference tracing device 100 and the square wave-based standard electronic transformer angle difference tracing method provided in the present application, on the basis of comparing the square wave voltage signal with the clock synchronization signal, the 50ns delay of the square wave voltage signal is compensated and deducted, which can achieve a delay of less than 10ns, which is converted to the corresponding fundamental wave delay phase of 0.0108 minutes, and the accuracy level is 3ppm in the national measurement standard. The delay of the square wave voltage signal can be further reduced, and then the fundamental wave delay phase corresponding to the square wave voltage signal can be reduced, which can make the accuracy level higher, better than the domestic 0.01% electronic transformer calibration device and the European 30ppm PMU calibration device, and can be used for the calibration of electronic transformer calibrators of level 0.01 and below.

[0096] In one embodiment, the conversion of the accuracy levels in the above embodiments may refer to JJG 313 Transformer Verification Procedure.

[0097] In one embodiment, in step S40, the step of tracing the angle difference of the electronic transformer under test based on the calibration angle difference calculated from the fundamental wave phase and the fundamental wave delayed phase includes: Step S410, obtaining a measurement angle difference obtained by measuring an input signal by the electronic transformer under test; Step S420: determining the actual angular difference of the electronic transformer under test based on the measured angular difference and the calibrated angular difference, so as to achieve angular difference tracing.

[0098] In this embodiment, when calibration or testing of an electronic transformer under test (e.g., an electronic transformer calibrator under test) is required, the input signal of the standard analog-to-digital conversion mutual inductance module 30 is converted to the same as the input signal of the electronic transformer under test via a voltage converter or a current converter, so that the standard analog-to-digital conversion mutual inductance module 30 and the electronic transformer under test have the same signal source input. The standard analog-to-digital conversion mutual inductance module 30 can serve as an electronic transformer or analog input merging unit, and as a calibration reference for the electronic transformer under test. Thus, the actual angular difference of the electronic transformer under test is obtained by subtracting the calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30 from the measured angular difference of the input signal of the electronic transformer under test, thereby achieving angular difference traceability for the electronic transformer under test.

[0099] Thus, through the square wave-based standard electronic transformer angular difference traceability device 100 and the square wave-based standard electronic transformer angular difference traceability method provided in this application, the angular difference of the electronic transformer under test can be measured based on the calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30, and the measurement result can be compared with the calibrated angular difference of the standard analog-to-digital conversion mutual inductance module 30 with a higher level of accuracy to determine the accuracy and uncertainty of the electronic transformer under test. The entire angular difference traceability process can be traced back to national measurement standards.

[0100] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0101] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0102] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0103] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0104] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0105] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0106] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0107] If the integrated module / unit is implemented as a software functional unit and sold or used as a standalone product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application can implement all or part of the process steps in the above-mentioned method embodiments by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal, and software distribution medium. It should be noted that the content of the computer-readable medium can be appropriately increased or decreased based on the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media does not include electric carrier signals and telecommunication signals.

[0108] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A standard electronic transformer angle difference tracing device based on square wave, characterized in that: include: A signal generating module (10), used for generating a square wave voltage signal and a clock synchronization signal; A delay phase determination module (20), connected to the signal generation module (10), and configured to determine a fundamental wave delay phase corresponding to the square wave voltage signal according to a rise time or a fall time of the square wave voltage signal; A standard analog-to-digital conversion mutual inductance module (30) is connected to the signal generation module (10) and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal; A calibration angle difference determination module (40) is connected to the standard analog-to-digital conversion mutual inductance module (30) and the delayed phase determination module (20), and is used to perform a discrete Fourier transform on the digital voltage signal to obtain a fundamental phase corresponding to the digital voltage signal, and perform angle difference tracing on the electronic mutual inductor under test based on a calibration angle difference calculated from the fundamental phase and the fundamental delayed phase.

2. The square wave-based standard electronic transformer angle difference tracing device according to claim 1, characterized in that: The signal generating module (10) comprises: A signal processing module (110) is used to generate a switch control signal and the clock synchronization signal, the signal processing module (110) is connected to the standard analog-to-digital conversion mutual inductance module (30), and is used to send the clock synchronization signal to the standard analog-to-digital conversion mutual inductance module (30); wherein the switch control signal is synchronized with the clock synchronization signal; A voltage generating module (120), used for generating a positive voltage signal and a negative voltage signal; The analog switch module (130) is connected to the signal processing module (110) and the voltage generating module (120) respectively, and is used to switch and output the positive voltage signal and the negative voltage signal according to the switch control signal to form the square wave voltage signal.

3. The square wave-based standard electronic transformer angle difference tracing device according to claim 2, characterized in that: The signal generating module (10) further comprises: The first operational amplifier module (140) is connected to the analog switch module (130) and the standard analog-to-digital conversion mutual inductance module (30), and is used to amplify the positive voltage signal and the negative voltage signal, and output the square wave voltage signal to the standard analog-to-digital conversion mutual inductance module (30).

4. The square wave-based standard electronic transformer angle difference tracing device according to claim 3, characterized in that: The standard analog-to-digital conversion mutual inductance module (30) comprises: The analog-to-digital conversion sampling module (310) is connected to the first operational amplifier module (140) and is used to filter and perform analog-to-digital conversion sampling on the square wave voltage signal to obtain a digital sampling signal.

5. The square wave-based standard electronic transformer angle difference tracing device according to claim 4, characterized in that: The standard analog-to-digital conversion mutual inductance module (30) further includes: A protocol conversion control module (320) is connected to the signal processing module (110) and the analog-to-digital conversion sampling module (310), and is used to control the analog-to-digital conversion sampling module (310) to perform analog-to-digital conversion sampling on the square wave voltage signal according to the clock synchronization signal, and to perform protocol conversion on the digital sampling signal to obtain the digital voltage signal, and to send the digital voltage signal to the calibration angle difference determination module (40) in the form of message data.

6. The square wave-based standard electronic transformer angle difference tracing device according to claim 3, characterized in that: The delay phase determination module (20) is connected to the first operational amplifier module (140) and is used to determine the fundamental wave delay phase corresponding to the square wave voltage signal according to the rise time of the square wave voltage signal.

7. The square wave-based standard electronic transformer angle difference tracing device according to any one of claims 2 to 6, characterized in that: The voltage generation module (120) comprises: A positive voltage generating module (121), used for outputting the positive voltage signal; The positive voltage generating module (121) is connected to the analog switch module (130) and is used to send the positive voltage signal to the analog switch module (130).

8. The square wave-based standard electronic transformer angle difference tracing device according to claim 7, characterized in that: The voltage generation module (120) further includes: A first resistance module (122), one end of the first resistance module (122) being connected to the positive voltage generating module (121); a second operational amplifier module (123), wherein an inverting input terminal of the second operational amplifier module (123) is connected to the other end of the first resistance module (122), a non-inverting input terminal of the second operational amplifier module (123) is grounded, and an output terminal of the second operational amplifier module (123) is connected to the analog switch module (130) for sending the negative voltage signal to the analog switch module (130); A second resistance module (124), one end of the second resistance module (124) is connected to the other end of the first resistance module (122), and the other end of the second resistance module (124) is connected to the output end of the second operational amplifier module (123).

9. A square wave-based standard electronic transformer angle difference tracing method, characterized in that: include: Sending a square wave voltage signal and a clock synchronization signal through a signal generation module (10); The square wave voltage signal is received by a delay phase determination module (20), and a fundamental wave delay phase corresponding to the square wave voltage signal is determined according to a rise time or a fall time of the square wave voltage signal; The clock synchronization signal is received through a standard analog-to-digital conversion mutual inductance module (30), and analog-to-digital conversion sampling is performed on the square wave voltage signal according to the clock synchronization signal to obtain a digital voltage signal; The digital voltage signal is subjected to a discrete Fourier transform to obtain a fundamental wave phase corresponding to the digital voltage signal, and the angle difference of the electronic transformer under test is traced according to a calibration angle difference obtained by calculating the fundamental wave phase and the fundamental wave delayed phase.

10. The square wave-based standard electronic transformer angle difference tracing method according to claim 9, characterized in that: The step of tracing the angle difference of the electronic transformer under test based on the calibration angle difference calculated from the fundamental wave phase and the fundamental wave delayed phase comprises: Obtaining a measured angle difference obtained by measuring an input signal by the electronic transformer under test; The actual angular difference of the electronic transformer under test is determined according to the measured angular difference and the calibrated angular difference.

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