Power grid time-varying power calculation method based on zero drift calibration

Abstract

The invention relates to the technical field of power grid metering, in particular to a power grid time-varying power calculation method based on zero drift calibration, which comprises the following steps of: firstly, constructing a power grid time-varying power calculation system capable of compensating and calibrating phases of voltage and current; the system is composed of a current data acquisition unit, a voltage data acquisition unit, a data processing unit and a calibration unit, the current data acquisition unit is responsible for acquiring power grid current in real time, the voltage data acquisition unit synchronously acquires power grid voltage, and the calibration unit is responsible for outputting standard calibration signals. And the data processing unit calculates the phase difference between the voltage and the current and accurately adjusts the phase, so that effective compensation for zero drift is realized, and finally, the real-time power of the power grid is quickly and accurately calculated. According to the zero drift calibration technology, the time-varying power calculation precision and the reactive compensation effect of the power grid can be effectively improved, the real-time frequency modulation requirement is met, the stability of the power grid is enhanced, and the energy consumption loss is reduced.

Description

Technical Field

[0001] This invention relates to the field of power grid metering technology, and in particular to a method for calculating time-varying power of a power grid based on zero-point drift calibration. Background Technology

[0002] When large-scale renewable energy plants and numerous nonlinear power electronic devices are integrated into the power grid, the grid's frequency support capacity decreases, and even the overall stability of the power system is affected. Primary frequency regulation is a crucial means of maintaining grid frequency stability, and grid power, as an important electrical quantity characterizing the grid's operating state, is key data supporting primary frequency regulation. Currently, power calculation mainly involves two methods: calculating power based on Fast Fourier Transform (FFT) and calculating power by converting AC signals to true RMS values. However, the former is limited by sampling rate and the number of sampling points, posing challenges to real-time performance and accuracy in calculating signals from units with a rated frequency of 50Hz. While the latter's calculation speed meets industry requirements, its scalability and environmental adaptability are limited by hardware module characteristics.

[0003] In particular, the rapid development and technological advancements in the power industry, along with strengthened energy conservation and loss reduction management, have created a demand for reactive power compensation in many sectors, making reactive power compensation an indispensable and crucial component of power supply systems. The role of LC reactive power compensation devices in electronic power supply systems is to improve the power factor of the power grid, reduce losses in power transformers and transmission lines, increase power supply efficiency, and improve the power supply environment. Although current LC reactive power compensation devices offer advantages such as low cost, simple structure, and wide application, their methods for calculating time-varying power in the power grid are relatively complex, and their accuracy is difficult to guarantee.

[0004] To compensate for the deficiencies in real-time performance and data accuracy in power calculation, those skilled in the art have proposed many ideas and improvements for calculating time-varying power in power grids. For example, the invention patent CN115102194A, entitled "A High-Precision Calculation Method for Time-Variing Power in Power Grids," employs hardware acquisition and conversion of signals and introduces voltage-current correlation functions to improve the real-time performance of power calculation. This algorithm reduces the computational load of time-varying power signals from the power grid while also enhancing the environmental adaptability of the power algorithm, allowing for on-site calibration for different working environments.

[0005] Later experiments conducted by those skilled in the art revealed that while this algorithm slightly improved the calculation accuracy of time-varying power in the power grid, it remained relatively low. How to maximize calculation accuracy while ensuring that the calculation of time-varying power in the power grid is not overly complex (i.e., minimizing the computational load of the time-varying power signal and considering the practicality of the algorithm) has always been a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for calculating time-varying power in a power grid based on zero-drift calibration. This is achieved by constructing a power grid time-varying power calculation system comprised of a current data acquisition unit, a voltage data acquisition unit, a data processing unit, and a calibration unit, which is then integrated into a three-phase power grid. Specifically, the current data acquisition unit acquires the grid current signal in real time, the voltage data acquisition unit acquires the grid voltage signal synchronously, the calibration unit outputs a standard calibration signal, and the data processing unit calculates the phase difference between voltage and current and precisely adjusts the phase to effectively compensate for zero-drift, ultimately calculating the real-time power of the power grid quickly and accurately. The zero-drift calibration technology employed in this invention effectively improves the calculation accuracy of time-varying power in the power grid, optimizes reactive power compensation, meets the requirements of real-time frequency regulation, and provides an efficient and feasible technical solution for improving power grid stability and reducing energy losses.

[0007] The objective of this invention is achieved through the following approach:

[0008] A method for calculating the time-varying power of a power grid based on zero-point drift calibration is proposed. First, a power grid time-varying power calculation system capable of compensating and calibrating the phase of voltage and current is established. Then, the power grid time-varying power calculation system is connected to the three-phase power grid for which the power grid time-varying power calculation needs to be performed. Finally, the power grid time-varying power calculation system is used to calculate the power grid time-varying power of the three-phase power grid.

[0009] Preferably, the power grid time-varying power calculation system comprises a current data acquisition unit, a voltage data acquisition unit, a data processing unit, and a calibration unit. The current data acquisition unit is used to acquire the current signal of the three-phase power grid; the voltage data acquisition unit is used to acquire the voltage signal of the three-phase power grid; the data processing unit is used to calculate the real-time active power P, reactive power Q, and apparent power S of the power grid; and the calibration unit is used to output a standard calibration signal with a known phase angle.

[0010] The input terminals of the current data acquisition unit and the voltage data acquisition unit are both connected to the three-phase power grid. The output terminal of the current data acquisition unit is connected to the first input terminal of the data processing unit, and the output terminal of the voltage data acquisition unit is connected to the second input terminal of the data processing unit. The output terminal of the calibration unit is connected to the third input terminal of the data processing unit. The output terminal of the data processing unit is used to connect to the host computer and output the calculation results.

[0011] Preferably, the method of calculating the time-varying power of a three-phase power grid using a power grid time-varying power calculation system specifically includes the following steps:

[0012] 1) After connecting the power grid time-varying power calculation system to the three-phase power grid, start the power grid time-varying power calculation system;

[0013] 2) The current and voltage signals of the three-phase power grid are acquired in real time using the current data acquisition unit and the voltage data acquisition unit, respectively. The acquired real-time current is converted into analog current, and the acquired real-time voltage is converted into analog voltage.

[0014] 3) The data processing unit processes the analog current to obtain the effective value of the current I, and processes the analog voltage to obtain the effective value of the voltage V;

[0015] 4) Using the data processing unit, perform a Fast Fourier Transform on the effective values ​​of the current (I) and voltage (V) to obtain the fundamental current, fundamental voltage, and the phase angle between the fundamental current and fundamental voltage.

[0016] 5) Using the calibration unit, input the standard calibration signal to the data processing unit to calculate the phase angle between the fundamental current and the fundamental voltage. Phase difference with standard calibration signal And utilize this phase difference Adjusting the phase of the fundamental current or fundamental voltage, the phase angle between the fundamental current and fundamental voltage. Perform calibration so that the phase angle between the calibrated fundamental current and fundamental voltage is . It is zero;

[0017] 6) Using the effective values ​​of current I, voltage V, and the phase angle between the calibrated fundamental current and fundamental voltage. The time-varying power of the power grid is calculated, and finally output to the host computer in the form of an electrical signal from the output terminal of the data processing unit.

[0018] Preferably, the current data acquisition unit includes a current transformer with an AC-coupled amplifier circuit structure, the voltage data acquisition unit includes a voltage transformer with an AC-coupled amplifier circuit structure, the data processing unit includes a core board with an analog-to-digital converter module, and the calibration unit includes a calibration device capable of outputting a standard calibration signal for comparing the phase angle offset of the actual sampled signal.

[0019] The input terminal of the current transformer serves as the input terminal of the current data acquisition unit, used for connection to the three-phase power grid. The output terminal of the current transformer serves as the output terminal of the current data acquisition unit. The first input terminal of the core board serves as the first input terminal of the data processing unit, and the output terminal of the current transformer is connected to the first input terminal of the core board. The input terminal of the voltage transformer serves as the input terminal of the voltage data acquisition unit, used for connection to the three-phase power grid. The output terminal of the voltage transformer serves as the output terminal of the voltage data acquisition unit. The second input terminal of the core board serves as the second input terminal of the data processing unit, and the output terminal of the voltage transformer is connected to the second input terminal of the core board. The output terminal of the calibration device serves as the output terminal of the calibration unit. The third input terminal of the core board serves as the third input terminal of the data processing unit, and the output terminal of the calibration device is connected to the third input terminal of the core board.

[0020] Preferably, in step 2), the specific process of converting the acquired real-time current into analog current and the acquired real-time voltage into analog voltage includes the following steps:

[0021] 2-1) The core board is used to simultaneously control the current transformer and voltage transformer to collect the real-time current and real-time voltage in the three-phase power grid at a set sampling frequency.

[0022] 2-2) The real-time current enters the current transformer, and after being amplified and filtered by the isolation sampling and AC coupling amplifier circuit, the analog current is obtained; the real-time voltage is processed by the proportional voltage reduction of the resistor series voltage divider circuit, and then enters the voltage transformer. After being amplified and filtered by the electrical isolation and AC coupling amplifier circuit, the analog voltage is obtained.

[0023] Preferably, in step 3), obtaining the effective value of the current I specifically includes:

[0024] 3-A-1) The analog current enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital current;

[0025] 3-A-2) The time-domain discrete data of digital current is processed by first-order hysteresis filtering to obtain the filtered current;

[0026] 3-A-3) The filtered current is calculated using the root mean square (RMS) method to obtain the effective value of the current I.

[0027] Preferably, in step 3), obtaining the effective voltage value V specifically includes:

[0028] 3-B-1) The analog voltage enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital voltage;

[0029] 3-B-2) The time-domain discrete data of digital voltage is processed by first-order hysteresis filtering to obtain the filtered voltage;

[0030] 3-B-3) The effective value of the filtered voltage V is obtained by root mean square calculation.

[0031] Preferably, in step 6), the time-varying power of the power grid includes real-time active power P, which is calculated according to the following formula:

[0032]

[0033] In the formula, P is the active power of the power grid, in watts (W); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is calibrated based on zero-point drift, and the unit is radians (rad). This represents the proportion of active power in apparent power within the power grid.

[0034] Preferably, in step 6), the time-varying power of the power grid includes real-time reactive power Q, which is calculated according to the following formula:

[0035]

[0036] In the formula, Q is the reactive power of the power grid, in var; V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is calibrated based on zero-point drift, and the unit is radians (rad). This represents the proportion of reactive power in apparent power within the power grid.

[0037] Preferably, in step 6), the time-varying power of the power grid includes the real-time apparent power S, which is calculated according to the following formula:

[0038] S = V × I;

[0039] In the formula, S is the apparent power of the power grid, in volt-amperes (VA); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A).

[0040] The beneficial effects of this invention include the following:

[0041] A method for calculating the time-varying power of a power grid based on zero-point drift calibration is proposed. First, a power grid time-varying power calculation system capable of compensating and calibrating the phase of voltage and current is established. Then, the power grid time-varying power calculation system is connected to the three-phase power grid for which the power grid time-varying power calculation needs to be performed. Finally, the power grid time-varying power calculation system is used to calculate the power grid time-varying power of the three-phase power grid.

[0042] Traditional power grid calculations often suffer from phase measurement errors due to zero-point drift, which affects the accuracy of active power, reactive power, and apparent power. The time-varying power calculation system for power grids established in this invention can effectively correct voltage and current phase deviations caused by hardware manufacturing errors and environmental factors, and compensate for and calibrate the phases of voltage and current. Dynamic calibration effectively suppresses the accumulation of errors, thereby reducing the risk of power grid faults caused by inaccurate data.

[0043] In other words, precise phase calibration can significantly improve the accuracy of power calculation for time-varying grid power, providing reliable data support for grid operation status monitoring and load forecasting. Simultaneously, accurate grid power calculation results enable the entire system to respond more quickly to grid frequency changes, optimize primary frequency regulation control strategies, enhance the grid system's adaptability to complex operating conditions, effectively alleviate the problem of decreased frequency support capability in complex grid scenarios, improve the overall stability of the grid system, and ensure the safe, stable, efficient, and reliable operation of the grid, meeting the development needs of new grid systems.

[0044] Preferably, the power grid time-varying power calculation system comprises a current data acquisition unit, a voltage data acquisition unit, a data processing unit, and a calibration unit. The current data acquisition unit is used to acquire the current signal of the three-phase power grid; the voltage data acquisition unit is used to acquire the voltage signal of the three-phase power grid; the data processing unit is used to calculate the real-time active power P, reactive power Q, and apparent power S of the power grid; and the calibration unit is used to output a standard calibration signal with a known phase angle.

[0045] The input terminals of the current data acquisition unit and the voltage data acquisition unit are both connected to the three-phase power grid. The output terminal of the current data acquisition unit is connected to the first input terminal of the data processing unit, and the output terminal of the voltage data acquisition unit is connected to the second input terminal of the data processing unit. The output terminal of the calibration unit is connected to the third input terminal of the data processing unit. The output terminal of the data processing unit is used to connect to the host computer and output the calculation results.

[0046] In this invention, the power grid time-varying power calculation system acquires current and voltage signals from the three-phase power grid in real time through a current and voltage data acquisition unit, and transmits them to a data processing unit with three input terminals. The system supports parallel processing of current and voltage sampling data and the standard calibration signal output by the calibration unit, enabling the data processing unit to accurately calculate real-time apparent power S, active power P, and reactive power Q. The modular design of the entire power grid time-varying power calculation system not only possesses clear unit structure and ease of maintenance and upgrades, but also achieves high-precision dynamic monitoring of power grid parameters through the collaborative operation of each unit, effectively meeting the real-time monitoring needs of industrial power grids, substations, and other scenarios. Furthermore, the standard calibration signal output by the calibration unit can promptly eliminate phase errors, further improving the accuracy and reliability of power calculation, and providing solid data support for power grid system dispatching, energy efficiency management, fault diagnosis, and other tasks.

[0047] Preferably, the method of calculating the time-varying power of a three-phase power grid using a power grid time-varying power calculation system specifically includes the following steps:

[0048] 1) After connecting the power grid time-varying power calculation system to the three-phase power grid, start the power grid time-varying power calculation system;

[0049] 2) The current and voltage signals of the three-phase power grid are acquired in real time using the current data acquisition unit and the voltage data acquisition unit, respectively. The acquired real-time current is converted into analog current, and the acquired real-time voltage is converted into analog voltage.

[0050] 3) The data processing unit processes the analog current to obtain the effective value of the current I, and processes the analog voltage to obtain the effective value of the voltage V;

[0051] 4) Using the data processing unit, perform a Fast Fourier Transform on the effective values ​​of the current (I) and voltage (V) to obtain the fundamental current, fundamental voltage, and the phase angle between the fundamental current and fundamental voltage.

[0052] 5) Using the calibration unit, input the standard calibration signal to the data processing unit to calculate the phase angle between the fundamental current and the fundamental voltage. Phase difference with standard calibration signal And utilize this phase difference Adjusting the phase of the fundamental current or fundamental voltage, the phase angle between the fundamental current and fundamental voltage. Perform calibration so that the phase angle between the calibrated fundamental current and fundamental voltage is . It is zero;

[0053] 6) Using the effective values ​​of current I, voltage V, and the phase angle between the calibrated fundamental current and fundamental voltage. The time-varying power of the power grid is calculated, and finally output to the host computer in the form of an electrical signal from the output terminal of the data processing unit.

[0054] This invention ensures data timeliness by acquiring current and voltage signals from a three-phase power grid in real time; it utilizes Fast Fourier Transform to extract fundamental current, fundamental voltage, and phase angle, effectively eliminating harmonic interference and improving the accuracy of related data; further, a calibration unit calibrates the phase angle between the fundamental current and fundamental voltage, significantly reducing system errors and calibrating the phase angle to zero, further eliminating phase measurement deviations; finally, based on accurate RMS current and voltage values ​​and calibrated phase parameters, it calculates the time-varying power of the power grid. Through precise processing and error correction at multiple stages throughout the process, it significantly improves the accuracy and reliability of power grid time-varying power calculation, providing high-precision data support for power grid operation monitoring, load management, and energy efficiency optimization, meeting the high-precision requirements of power grid monitoring.

[0055] Preferably, the current data acquisition unit includes a current transformer with an AC-coupled amplifier circuit structure, the voltage data acquisition unit includes a voltage transformer with an AC-coupled amplifier circuit structure, the data processing unit includes a core board with an analog-to-digital converter module, and the calibration unit includes a calibration device capable of outputting a standard calibration signal for comparing the phase angle offset of the actual sampled signal.

[0056] The input terminal of the current transformer serves as the input terminal of the current data acquisition unit, used for connection to the three-phase power grid. The output terminal of the current transformer serves as the output terminal of the current data acquisition unit. The first input terminal of the core board serves as the first input terminal of the data processing unit, and the output terminal of the current transformer is connected to the first input terminal of the core board. The input terminal of the voltage transformer serves as the input terminal of the voltage data acquisition unit, used for connection to the three-phase power grid. The output terminal of the voltage transformer serves as the output terminal of the voltage data acquisition unit. The second input terminal of the core board serves as the second input terminal of the data processing unit, and the output terminal of the voltage transformer is connected to the second input terminal of the core board. The output terminal of the calibration device serves as the output terminal of the calibration unit. The third input terminal of the core board serves as the third input terminal of the data processing unit, and the output terminal of the calibration device is connected to the third input terminal of the core board.

[0057] In this invention, the current data acquisition unit uses a current transformer with an AC-coupled amplifier circuit structure, and the voltage data acquisition unit uses a voltage transformer with an AC-coupled amplifier circuit structure. This effectively suppresses DC bias interference and amplifies weak signals, improving the acquisition accuracy and anti-interference capability of real-time current and voltage signals. The analog-to-digital converter module equipped on the core board can accurately convert analog signals into digital signals, providing a foundation for subsequent digital signal processing. The calibration equipment is used to output a standard calibration signal, which achieves real-time calibration of the measurement system by comparing the phase angle offset, further eliminating system errors.

[0058] In other words, the units of this invention form a closed-loop system through a clear input-output relationship, which not only ensures the accuracy of signal acquisition, but also compensates for possible deviations in the signal processing through a calibration mechanism, ultimately significantly improving the accuracy and reliability of power grid time-varying power calculation.

[0059] Preferably, in step 2), the specific process of converting the acquired real-time current into analog current and the acquired real-time voltage into analog voltage includes the following steps:

[0060] 2-1) The core board is used to simultaneously control the current transformer and voltage transformer to collect the real-time current and real-time voltage in the three-phase power grid at a set sampling frequency.

[0061] 2-2) The real-time current enters the current transformer, and after being amplified and filtered by the isolation sampling and AC coupling amplifier circuit, the analog current is obtained; the real-time voltage is processed by the proportional voltage reduction of the resistor series voltage divider circuit, and then enters the voltage transformer. After being amplified and filtered by the electrical isolation and AC coupling amplifier circuit, the analog voltage is obtained.

[0062] This invention ensures the time synchronization of current and voltage signals by synchronously controlling the sampling frequencies of the current and voltage transformers through a core board, avoiding phase calculation errors caused by differences in sampling timing. The current transformer employs isolated sampling and AC-coupled amplification circuits, achieving both electrical isolation to ensure system safety and amplification and filtering to improve weak signal quality and suppress noise interference. The voltage transformer first uses a resistor divider to proportionally reduce the voltage, converting high voltage to a safe range, and then further optimizes signal quality through electrical isolation and AC-coupled amplification circuits. This phased and targeted signal conditioning method ensures the complete transmission of the original signal characteristics while effectively filtering out interference noise, significantly improving the signal quality of analog current and analog voltage.

[0063] Preferably, in step 3), obtaining the effective value of the current I specifically includes:

[0064] 3-A-1) The analog current enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital current;

[0065] 3-A-2) The time-domain discrete data of digital current is processed by first-order hysteresis filtering to obtain the filtered current;

[0066] 3-A-3) The filtered current is calculated using the root mean square (RMS) method to obtain the effective value of the current I.

[0067] Preferably, in step 3), obtaining the effective voltage value V specifically includes:

[0068] 3-B-1) The analog voltage enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital voltage;

[0069] 3-B-2) The time-domain discrete data of digital voltage is processed by first-order hysteresis filtering to obtain the filtered voltage;

[0070] 3-B-3) The effective value of the filtered voltage V is obtained by root mean square calculation.

[0071] This invention employs high-frequency sampling of analog current and voltage via a core board, capturing more signal details and ensuring the integrity and richness of the discrete-time data for digital current and voltage. First-order hysteresis filtering effectively smooths high-frequency noise and transient fluctuations in the signal, reducing the impact of interference and making the filtered current and voltage closer to the real signal. The effective values ​​are then calculated using the root mean square (RMS) value, conforming to the physical definition of the effective value of sinusoidal alternating current, accurately reflecting the actual work capacity of the current and voltage. Through this series of processing steps, key signal characteristics are preserved while interference factors are eliminated, significantly improving the calculation accuracy of the effective current value (I) and the effective voltage value (V).

[0072] Preferably, in step 6), the time-varying power of the power grid includes real-time active power P, which is calculated according to the following formula:

[0073]

[0074] In the formula, P is the active power of the power grid, in watts (W); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is calibrated based on zero-point drift, and the unit is radians (rad). This represents the proportion of active power in apparent power within the power grid.

[0075] Preferably, in step 6), the time-varying power of the power grid includes real-time reactive power Q, which is calculated according to the following formula:

[0076]

[0077] In the formula, Q is the reactive power of the power grid, in var; V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is calibrated based on zero-point drift, and the unit is radians (rad). This represents the proportion of reactive power in apparent power within the power grid.

[0078] Preferably, in step 6), the time-varying power of the power grid includes the real-time apparent power S, which is calculated according to the following formula:

[0079] S = V × I;

[0080] In the formula, S is the apparent power of the power grid, in volt-amperes (VA); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A).

[0081] This invention calculates the time-varying active power P, reactive power Q, and apparent power S of the power grid based on accurately acquired real-time RMS voltage and current values, as well as the phase angle calibrated by zero-point drift, thus comprehensively presenting the multi-dimensional characteristics of power grid power. Specifically, by utilizing the calibrated phase angle and corresponding trigonometric function values, the proportions of active and reactive power in apparent power are accurately quantified. This ensures both the theoretical rigor of the power calculation and the high precision of the input parameters through accurate acquisition and phase calibration of voltage and current signals, significantly improving the accuracy and reliability of the three types of power calculation results. This comprehensive and accurate method for calculating time-varying power in the power grid provides detailed and reliable data for practical applications such as power grid load analysis, energy efficiency assessment, and reactive power compensation.

[0082] In summary, the advantages of this invention are as follows:

[0083] ① This invention constructs a power grid time-varying power calculation system based on dynamic phase calibration with zero-point drift compensation. It utilizes real-time comparison of the phase angle between the standard calibration signal and the actual sampled signal to form a closed-loop calibration mechanism of "error detection-compensation adjustment." This mechanism can correct phase deviations caused by factors such as transformer manufacturing tolerances and temperature drift in real time, effectively improving phase measurement accuracy. Simultaneously, this invention integrates power electronics, signal processing, and digital control technologies. It suppresses DC bias through the AC coupling amplifier circuit of the current / voltage transformer and achieves voltage adaptation through a resistor voltage divider circuit, effectively improving the signal-to-noise ratio. This fundamentally solves the error accumulation problem caused by zero-point drift in traditional power calculations.

[0084] ② The power grid time-varying power calculation system adopted in this invention consists of four independent units: current data acquisition, voltage data acquisition, data processing, and calibration. Each unit interacts with signals through standardized interfaces, enabling clear fault location logic for hardware maintenance. Module-level replacement significantly reduces costs compared to traditional whole-system replacement. Simultaneously, through electrical isolation technology, signal processing anti-interference measures, and calibration anti-interference mechanisms, a multi-layered anti-interference system is constructed, meeting the IEC 61000-4-5 industrial immunity standard, greatly improving the adaptability of the entire power grid time-varying power calculation system in complex industrial environments.

[0085] ③ This invention effectively improves the calculation accuracy of time-varying power in the power grid through a composite algorithm of "time-domain filtering and frequency-domain analysis". First, by sampling analog current and voltage at high frequency, the time-domain discrete data of digital current and voltage are processed by first-order lag filtering. The root mean square calculation of the filtered current and voltage is then performed to control the calculation error of the current / voltage RMS value within ±0.2%. Next, by performing a fast Fourier transform on the current / voltage RMS value, the fundamental component is accurately separated, and the phase information is precisely obtained. Finally, a standard calibration signal is introduced to calculate the phase difference, effectively correcting the phase deviation caused by hardware manufacturing errors, environmental factors, etc., and combined with zero-point drift compensation, the phase calculation resolution is further improved. More importantly, the entire power grid time-varying power calculation system cyclically executes the "sampling-calibration-calculation" process at a set sampling frequency. It can complete phase calibration within 20ms when the power grid operating conditions change abruptly. Its dynamic response speed is significantly improved compared with traditional static calibration technology, and it is especially suitable for dynamic scenarios such as new energy grid connection.

[0086] ④ This invention constructs a time-varying power calculation system for power grids based on zero-point drift calibration, which can accurately calculate the real-time active power, reactive power, and apparent power of the power grid, minimizing power losses caused by phase errors in traditional calculations. On the one hand, accurate power calculation results enable the system to respond quickly to changes in power grid frequency, optimize primary frequency regulation control strategies, and reduce unnecessary energy consumption. On the other hand, its dynamic calibration mechanism effectively suppresses error accumulation, providing reliable data for power grid operation status monitoring and load forecasting, helping the power grid achieve more efficient energy allocation and scheduling, thereby effectively promoting the improvement of power grid energy efficiency and meeting the green and low-carbon development needs of new power grid systems.

[0087] ⑤ This invention, through a closed-loop design of “signal conditioning-digital conversion-filter calibration-real-time calculation”, not only achieves anti-interference processing of complex signals of three-phase power grids, but also eliminates systematic errors through calibration mechanisms, thereby further improving the accuracy of power calculation. It provides technical support with both reliability and real-time performance for smart grid dispatching, real-time load monitoring and energy efficiency optimization. Attached Figure Description

[0088] Figure 1 This is a schematic diagram showing the connection between the internal unit of the power grid time-varying power calculation system and the three-phase power grid in this invention;

[0089] Figure 2 This is a flowchart of the power grid time-varying power calculation based on zero-point drift according to the present invention;

[0090] Figure 3 This is a system schematic diagram in an embodiment of the present invention;

[0091] Figure 4 This is a flowchart of the power grid time-varying power calculation based on zero-point drift in an embodiment of the present invention;

[0092] Figure 5 This is a circuit block diagram of the time-varying power calculation method for power grids based on zero-point drift in an embodiment of the present invention;

[0093] Figure 6 This is a circuit schematic diagram of the analog-to-digital converter used in this invention;

[0094] Figure 7 This is a sampling circuit diagram of the ZMCT103C current transformer used in this embodiment of the invention;

[0095] Figure 8 This is a sampling circuit diagram of the voltage transformer ZMPT101K used in this embodiment of the invention. Detailed Implementation

[0096] like Figures 1 to 2 As shown, a method for calculating the time-varying power of a power grid based on zero-point drift calibration is proposed. First, a power grid time-varying power calculation system capable of compensating for the phase of voltage and current is established. Then, this system is connected to the three-phase power grid for which the time-varying power calculation needs to be performed. Finally, the power grid time-varying power calculation system is used to calculate the power grid time-varying power of the three-phase power grid in the following manner:

[0097] 1) After connecting the power grid time-varying power calculation system to the three-phase power grid, start the power grid time-varying power calculation system;

[0098] 2) The current and voltage signals of the three-phase power grid are acquired in real time using current and voltage data acquisition units, respectively. The acquired real-time current is converted into analog current, and the acquired real-time voltage is converted into analog voltage in the following manner:

[0099] 2-1) The core board is used to simultaneously control the current transformer and voltage transformer to collect the real-time current and real-time voltage in the three-phase power grid at a set sampling frequency.

[0100] 2-2) The real-time current enters the current transformer, and after being amplified and filtered by the isolation sampling and AC coupling amplifier circuit, the analog current is obtained; the real-time voltage is processed by the proportional voltage reduction of the resistor series voltage divider circuit, and then enters the voltage transformer. After being amplified and filtered by the electrical isolation and AC coupling amplifier circuit, the analog voltage is obtained.

[0101] 3) The data processing unit processes the analog current to obtain the effective value of the current I, and processes the analog voltage to obtain the effective value of the voltage V.

[0102] Step 3), obtaining the effective value of the current I, specifically includes:

[0103] 3-A-1) The analog current enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital current;

[0104] 3-A-2) The time-domain discrete data of digital current is processed by first-order hysteresis filtering to obtain the filtered current;

[0105] 3-A-3) The filtered current is calculated using the root mean square (RMS) method to obtain the effective value of the current I.

[0106] Step 3), obtaining the effective voltage value V, specifically includes:

[0107] 3-B-1) The analog voltage enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital voltage;

[0108] 3-B-2) The time-domain discrete data of digital voltage is processed by first-order hysteresis filtering to obtain the filtered voltage;

[0109] 3-B-3) The effective value of the filtered voltage V is obtained by root mean square calculation.

[0110] 4) Using the data processing unit, perform a Fast Fourier Transform on the effective values ​​of the current (I) and voltage (V) to obtain the fundamental current, fundamental voltage, and the phase angle between the fundamental current and fundamental voltage.

[0111] 5) Using the calibration unit, input the standard calibration signal to the data processing unit to calculate the phase angle between the fundamental current and the fundamental voltage. Phase difference with standard calibration signal And utilize this phase difference Adjusting the phase of the fundamental current or fundamental voltage, the phase angle between the fundamental current and fundamental voltage. Perform calibration so that the phase angle between the calibrated fundamental current and fundamental voltage is . It is zero;

[0112] 6) Using the effective values ​​of current I, voltage V, and the phase angle between the calibrated fundamental current and fundamental voltage. The time-varying power of the power grid is calculated and finally output to the host computer (i.e., external device) in the form of an electrical signal from the output terminal of the data processing unit. The time-varying power of the power grid includes real-time active power P, reactive power Q, and apparent power S, calculated according to the following formula:

[0113] Active power

[0114] reactive power

[0115] Apparent power S = V × I

[0116] In the formula, P is the active power of the power grid, in watts (W); Q is the reactive power of the power grid, in vars (var); S is the apparent power of the power grid, in volt-amperes (VA); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is based on zero-point drift calibration, in radians (rad); cos This represents the proportion of active power in apparent power within the power grid. This represents the proportion of reactive power in apparent power within the power grid.

[0117] It is worth noting that the power grid time-varying power calculation system described in this invention consists of a current data acquisition unit, a voltage data acquisition unit, a data processing unit, and a calibration unit. The current data acquisition unit is used to acquire the current signal of the three-phase power grid; the voltage data acquisition unit is used to acquire the voltage signal of the three-phase power grid; the data processing unit is used to calculate the real-time active power P, reactive power Q, and apparent power S of the power grid; and the calibration unit is used to output a standard calibration signal with a known phase angle.

[0118] The input terminals of the current data acquisition unit and the voltage data acquisition unit are both connected to the three-phase power grid. The output terminal of the current data acquisition unit is connected to the first input terminal of the data processing unit, and the output terminal of the voltage data acquisition unit is connected to the second input terminal of the data processing unit. The output terminal of the calibration unit is connected to the third input terminal of the data processing unit. The output terminal of the data processing unit is used to connect to the host computer and output the calculation results.

[0119] Specifically, the current data acquisition unit includes a current transformer with an AC-coupled amplifier circuit structure, the voltage data acquisition unit includes a voltage transformer with an AC-coupled amplifier circuit structure, the data processing unit includes a core board with an analog-to-digital converter module, and the calibration unit includes a calibration device that can output a standard calibration signal for comparing the phase angle offset of the actual sampled signal.

[0120] The input terminal of the current transformer serves as the input terminal of the current data acquisition unit, used for connection to the three-phase power grid. The output terminal of the current transformer serves as the output terminal of the current data acquisition unit. The first input terminal of the core board serves as the first input terminal of the data processing unit (i.e., the current data input terminal), and the output terminal of the current transformer is connected to the first input terminal of the core board. The input terminal of the voltage transformer serves as the input terminal of the voltage data acquisition unit, used for connection to the three-phase power grid. The output terminal of the voltage transformer serves as the output terminal of the voltage data acquisition unit. The second input terminal of the core board serves as the second input terminal of the data processing unit (i.e., the voltage data input terminal), and the output terminal of the voltage transformer is connected to the second input terminal of the core board. The output terminal of the calibration device serves as the output terminal of the calibration unit. The third input terminal of the core board serves as the third input terminal of the data processing unit (i.e., the calibration signal input terminal), and the output terminal of the calibration device is connected to the third input terminal of the core board.

[0121] Based on the above, the following is an example:

[0122] The core board selected is STM32F103VET6; the current transformer selected is ZMCT103C; the voltage transformer selected is ZMPT101K; the calibration equipment selected is a three-phase standard source, and a time-varying power calculation system for the power grid is established.

[0123] In this embodiment, the time-varying power of the three-phase power grid is calculated using a power grid time-varying power calculation system in the following manner:

[0124] (1) Connect the input terminal of the current transformer in the power grid time-varying power calculation system to the three-phase power grid (i.e., connect it to the power consumption side), and connect the input terminal of the voltage transformer to the three-phase power grid through a series resistor voltage divider circuit. Then power on and start the power grid time-varying power calculation system.

[0125] (2) The core board inside the data processing unit of the power grid time-varying power calculation system controls the current transformer and voltage transformer to collect the real-time current and real-time voltage in the three-phase power grid at a sampling frequency of 16KHZ.

[0126] In practical application scenarios, for the real-time current and voltage acquisition process of the three-phase power grid involved in this system, the above sampling frequency value must meet the condition of not less than 3.2KHZ, and within the range above the lower limit, there is no upper limit on the specific value of the sampling frequency.

[0127] (3) The real-time current in the three-phase power grid flows into the current transformer from the input terminal and enters the current transformer. After being isolated and sampled by the current transformer and amplified and filtered by the internal AC coupling amplifier circuit, the analog current is obtained.

[0128] Here, the current transformer serves two purposes: first, it converts the real-time current in the three-phase power grid from high current (e.g., hundreds of amperes) to low current through electromagnetic induction, achieving electrical isolation and ensuring the safety of downstream circuits; second, it uses an internal AC coupling amplifier circuit to perform capacitive DC blocking on the isolated low-current signal, i.e., removing the DC bias and retaining only the AC component; then, it amplifies the signal to the range that the analog-to-digital converter in the core board used in this invention can acquire, and then filters out high-frequency noise, retaining its fundamental frequency and main harmonic components, ultimately obtaining an analog current signal. This invention refers to this analog current signal as analog current.

[0129] At the same time, the real-time voltage in the three-phase power grid is proportionally stepped down through a series resistor voltage divider circuit to obtain a voltage signal that is compatible with the voltage transformer. This voltage signal flows in from the input terminal of the voltage transformer and enters the voltage transformer. After being amplified and filtered by the voltage transformer's electrical isolation and AC coupling amplifier circuit, an analog voltage is obtained.

[0130] Here, the resistor series voltage divider circuit reduces the real-time voltage (high voltage) to the rated input range of the voltage transformer, achieving preliminary voltage reduction. The voltage transformer has two functions: first, it converts the initially reduced voltage into a lower secondary-side voltage while providing electrical isolation to ensure safety; second, it uses an internal AC coupling amplifier circuit to perform capacitive DC blocking on the isolated secondary-side voltage, i.e., removing the DC bias and retaining only the AC component. The signal is then amplified to the range that the analog-to-digital converter in the core board used in this invention can acquire. After filtering out high-frequency noise, it retains its fundamental frequency and main harmonic components, ultimately obtaining an analog voltage signal. This invention refers to this analog voltage signal as analog voltage.

[0131] (4) The analog current obtained in step (3) flows out from the output terminal of the current transformer and into the first input terminal of the core board, and enters the core board; the analog current is sampled at high frequency by the analog-to-digital converter inside the core board to obtain the time-domain discrete data of the digital current.

[0132] Meanwhile, the analog voltage obtained in step (3) flows out from the output of the voltage transformer and into the second input of the core board, entering the core board; the analog voltage is sampled at high frequency by the analog-to-digital converter inside the core board to obtain the time-domain discrete data of the digital voltage.

[0133] Here, the analog-to-digital converter (ADC) is used to convert continuous analog signals into discrete digital signals. In other words, by using the ADC inside the core board to sample analog current and voltage at high frequency, discrete digital current and voltage values ​​are obtained, i.e., digital current sequences and digital voltage sequences. This invention collectively refers to these digital current sequences and digital voltage sequences as time-domain discrete data of digital current and time-domain discrete data of digital voltage.

[0134] (5) Using the discrete time-domain data of the digital current obtained in step (4), the CPU inside the core board performs first-order hysteresis filtering on the discrete time-domain data of the digital current to obtain the filtered current; using the discrete time-domain data of the digital voltage obtained in step (4), the CPU inside the core board performs first-order hysteresis filtering on the discrete time-domain data of the digital voltage to obtain the filtered voltage.

[0135] Here, the central processing unit inside the core board primarily undertakes the core role of digital signal processing. It performs a first-order hysteresis filtering algorithm on the digital current and digital voltage, processing their discrete time-domain data in real time to obtain smoothed and denoised filtered current and voltage sequences. In this invention, these filtered current and voltage sequences are collectively referred to as filtered current and filtered voltage.

[0136] (6) The filter current obtained in step (5) is calculated by the root mean square of the filter current using the central processing unit inside the core board to obtain the effective value of the current I; the filter voltage obtained in step (5) is calculated by the root mean square of the filter voltage using the central processing unit inside the core board to obtain the effective value of the voltage V.

[0137] Specifically, the aforementioned effective current value I and effective voltage value V are important indicators for evaluating power grid stability and equipment load capacity, and are used to characterize the equivalent DC effect of alternating current. Specifically, the effective current value I characterizes the equivalent DC value of alternating current in terms of thermal effects; the effective voltage value V characterizes the equivalent DC value of alternating voltage.

[0138] (7) Perform a fast Fourier transform on the current effective value I obtained in step (6) to obtain the complex form of the fundamental current; perform a fast Fourier transform on the voltage effective value V obtained in step (6) to obtain the complex form of the fundamental voltage; calculate the phase angle between the fundamental current and the fundamental voltage based on the complex forms of the fundamental current and the fundamental voltage.

[0139] In this embodiment, the phase angle between the fundamental current and the fundamental voltage is...

[0140] Specifically, the Fast Fourier Transform converts the time-domain signal (i.e., the changes of the effective current value I and the effective voltage value V over time) into a frequency-domain representation, which can reveal the distribution of each frequency component in the signal.

[0141] By performing a Fast Fourier Transform on the RMS current value I and the RMS voltage value V, the frequency domain spectrum distribution of the current and voltage can be obtained (specifically including the amplitude, phase, and frequency information of each harmonic). Then, by filtering the frequencies of the current and voltage and calculating the relevant phases from the frequency domain spectrum distribution of the current and voltage, the fundamental current, fundamental voltage, and their phase angle can be finally obtained.

[0142] (8) Using the calibration equipment in the power grid time-varying power calculation system, input a phase angle of zero (i.e., ...) to the data processing unit. The standard calibration signal is used by the data processing unit to compare the phase angle between the fundamental current and the fundamental voltage in step (7). The phase angle between the input standard calibration signal and the input standard calibration signal Calculate the phase difference 0° = 20°, using this phase difference The phase of the fundamental current is adjusted to ensure that the phase angle between the fundamental current and the fundamental voltage returns to zero synchronously. At this point, the zero-point drift compensation value is determined. The phase angle between the calibrated fundamental current and fundamental voltage is: The phase angle between this value and the standard calibration signal The zero-point drift calibration was completed in accordance with the agreement.

[0143] (9) The effective current value I and effective voltage value V obtained in step (6) and the phase angle between the calibrated fundamental current and fundamental voltage obtained in step (8). The time-varying power of the power grid can be calculated, that is:

[0144] Active power

[0145] reactive power

[0146] Apparent power S = V × I

[0147] In the formula, P is the active power of the power grid, in watts (W); Q is the reactive power of the power grid, in vars (var); S is the apparent power of the power grid, in volt-amperes (VA); V is the real-time effective value of voltage, in volts (V); and I is the real-time effective value of current, in amperes (A). The phase angle is based on zero-point drift calibration, in radians (rad); cos This represents the proportion of active power in apparent power within the power grid. This represents the proportion of reactive power in apparent power within the power grid.

[0148] The calculated real-time data of active power P, reactive power Q, and apparent power S are transmitted from the output of the data processing unit to external devices in the form of electrical signals. This can be applied to the following scenarios: First, it provides quantitative data for monitoring the power grid's operational status. Through the analysis of real-time power parameters, it intuitively presents key indicators such as the grid's load characteristics and power quality, helping maintenance personnel understand the grid's operating status. Second, based on the output power parameters, it triggers reactive power compensation devices or load regulating mechanisms. By dynamically adjusting the injection or consumption of reactive power, it achieves closed-loop control of the grid's power factor, effectively improving grid energy efficiency and stability. Third, it transmits real-time power data to a remote management platform via a communication interface, supporting remote analysis of grid operation data, fault early warning, and multi-regional collaborative scheduling, promoting intelligent management and optimized operation of the power grid.

[0149] (10) The core board will continuously execute steps (2), (3), (4), (5), (6), (7) and (9) to realize the real-time calculation of the time-varying parameters of the power grid.

[0150] Finally, to fully verify the technical effects of the present invention and demonstrate the effectiveness of the zero-point drift calibration step in improving measurement accuracy, a comparative experiment was conducted as follows. The data in Tables 1 and 2 verify the measurement accuracy and reliability of the present invention:

[0151] Table 1. Phase A Current, Voltage, and Power Factors without Zero-Point Phase Calibration

[0152]

[0153] By setting the voltage and current parameters of a three-phase standard source, a phase difference condition within the range of 0°-35° is simulated (i.e., the phase difference ∠UI of voltage and current is adjusted to 0°-35°), and then the power factor cos(φ) measured by the prototype is read. A The data shown in Table 1 is obtained by comparing the reference data cos(φref) with the standard source. At this point, the prototype had not undergone zero-point phase calibration. It can be seen that without current and voltage phase calibration, the power factor error initially decreases and then increases. This is because there are errors in the phase measurements of voltage and current, leading to an error in the phase difference between them, which in turn affects the accuracy of reactive power measurement. Therefore, it is necessary to calibrate the zero-point phase drift. Through statistical analysis, the phase deviation that needs to be compensated is... The calibrated phase difference is Based on the calibrated phase difference, the data shown in Table 2 can be obtained. That is, after zero-point phase calibration, the measurement accuracy of reactive power of the A-phase power grid is significantly improved. Since reactive power, apparent power and active power satisfy a trigonometric function relationship, it can be seen that the measurement accuracy of the other two is also improved, thereby improving the measurement accuracy of time-varying parameters of the power grid.

[0154] Table 2. Phase A current, voltage, and power factors after zero-point phase calibration.

[0155]

[0156] By comparing and analyzing the power factor data obtained from the above measurements with the standard source reference data, the optimization effect of zero-point phase calibration on the system measurement performance can be evaluated intuitively and quantitatively, providing practical data support for the reliability and practicality of this invention in the field of power grid parameter measurement.

[0157] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for calculating time-varying power of a power grid based on zero-point drift calibration, characterized in that, First, establish a power grid time-varying power calculation system capable of compensating and calibrating the phase of voltage and current. Then, connect this power grid time-varying power calculation system to the three-phase power grid that needs to be calculated for power grid time-varying power. Finally, use the power grid time-varying power calculation system to calculate the power grid time-varying power of the three-phase power grid.

2. The method for calculating time-varying power in a power grid according to claim 1, characterized in that, The power grid time-varying power calculation system consists of a current data acquisition unit, a voltage data acquisition unit, a data processing unit, and a calibration unit. The current data acquisition unit is used to acquire the current signal of the three-phase power grid. The voltage data acquisition unit is used to acquire the voltage signal of the three-phase power grid; the data processing unit is used to calculate the real-time active power P, reactive power Q and apparent power S of the power grid; the calibration unit is used to output a standard calibration signal with a known phase angle. The input terminals of the current data acquisition unit and the voltage data acquisition unit are both connected to the three-phase power grid. The output terminal of the current data acquisition unit is connected to the first input terminal of the data processing unit, and the output terminal of the voltage data acquisition unit is connected to the second input terminal of the data processing unit. The output terminal of the calibration unit is connected to the third input terminal of the data processing unit. The output terminal of the data processing unit is used to connect to the host computer and output the calculation results.

3. The method for calculating time-varying power in a power grid according to claim 2, characterized in that, Methods for calculating the time-varying power of a three-phase power grid using a power grid time-varying power calculation system include: 1) After connecting the power grid time-varying power calculation system to the three-phase power grid, start the power grid time-varying power calculation system; 2) The current and voltage signals of the three-phase power grid are acquired in real time using the current data acquisition unit and the voltage data acquisition unit, respectively. The acquired real-time current is converted into analog current and the acquired real-time voltage is converted into analog voltage. 3) The data processing unit processes the analog current to obtain the effective value of the current I, and processes the analog voltage to obtain the effective value of the voltage V; 4) Using the data processing unit, perform a Fast Fourier Transform on the effective values ​​of the current (I) and voltage (V) to obtain the fundamental current, fundamental voltage, and the phase angle between the fundamental current and fundamental voltage. 5) Using the calibration unit, input the standard calibration signal to the data processing unit to calculate the phase angle between the fundamental current and the fundamental voltage. Phase difference with standard calibration signal And utilize this phase difference Adjusting the phase of the fundamental current or fundamental voltage, the phase angle between the fundamental current and fundamental voltage. Perform calibration so that the phase angle between the calibrated fundamental current and fundamental voltage is . It is zero; 6) Using the effective values ​​of current I, voltage V, and the phase angle between the calibrated fundamental current and fundamental voltage. The time-varying power of the power grid is calculated, and finally output to the host computer in the form of an electrical signal from the output terminal of the data processing unit.

4. The method for calculating time-varying power in a power grid according to claim 2 or 3, characterized in that, The current data acquisition unit includes a current transformer with an AC-coupled amplifier circuit structure, the voltage data acquisition unit includes a voltage transformer with an AC-coupled amplifier circuit structure, the data processing unit includes a core board with an analog-to-digital converter module, and the calibration unit includes a calibration device that can output a standard calibration signal for comparing the phase angle offset of the actual sampled signal. The input terminal of the current transformer serves as the input terminal of the current data acquisition unit, used for connection to the three-phase power grid. The output terminal of the current transformer serves as the output terminal of the current data acquisition unit. The first input terminal of the core board serves as the first input terminal of the data processing unit, and the output terminal of the current transformer is connected to the first input terminal of the core board. The input terminal of the voltage transformer serves as the input terminal of the voltage data acquisition unit, used for connection to the three-phase power grid. The output terminal of the voltage transformer serves as the output terminal of the voltage data acquisition unit. The second input terminal of the core board serves as the second input terminal of the data processing unit, and the output terminal of the voltage transformer is connected to the second input terminal of the core board. The output terminal of the calibration device serves as the output terminal of the calibration unit. The third input terminal of the core board serves as the third input terminal of the data processing unit, and the output terminal of the calibration device is connected to the third input terminal of the core board.

5. The method for calculating time-varying power in a power grid according to claim 4, characterized in that, Step 2) involves converting the acquired real-time current into analog current and the acquired real-time voltage into analog voltage. The specific process includes the following steps: 2-1) The core board is used to simultaneously control the current transformer and voltage transformer to collect the real-time current and real-time voltage in the three-phase power grid at a set sampling frequency. 2-2) The real-time current enters the current transformer, and after being amplified and filtered by the isolation sampling and AC coupling amplifier circuit, the analog current is obtained; the real-time voltage is processed by the proportional voltage reduction of the resistor series voltage divider circuit, and then enters the voltage transformer. After being amplified and filtered by the electrical isolation and AC coupling amplifier circuit, the analog voltage is obtained.

6. The method for calculating time-varying power in a power grid according to claim 4, characterized in that, Step 3), obtaining the effective value of the current I, specifically includes: 3-A-1) The analog current enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital current; 3-A-2) The time-domain discrete data of digital current is processed by first-order hysteresis filtering to obtain the filtered current; 3-A-3) The filtered current is calculated using the root mean square (RMS) method to obtain the effective value of the current I.

7. The method for calculating time-varying power in a power grid according to claim 4, characterized in that, Step 3), obtaining the effective voltage value V, specifically includes: 3-B-1) The analog voltage enters the core board and, after high-frequency sampling processing, obtains the time-domain discrete data of the digital voltage; 3-B-2) The time-domain discrete data of digital voltage is processed by first-order hysteresis filtering to obtain the filtered voltage; 3-B-3) The effective value of the filtered voltage V is obtained by root mean square calculation.

8. The method for calculating time-varying power in a power grid according to claim 3, characterized in that, In step 6), the time-varying power of the power grid includes the real-time active power P, which is calculated according to the following formula: In the formula, P represents the active power of the power grid, V represents the real-time RMS voltage, and I represents the real-time RMS current. The phase angle is based on the zero-point drift calibration. This represents the proportion of active power in apparent power in a three-phase power grid.

9. The method for calculating time-varying power in a power grid according to claim 3, characterized in that, In step 6), the time-varying power of the power grid includes real-time reactive power Q, which is calculated according to the following formula: In the formula, Q represents the reactive power of the power grid, V represents the real-time RMS voltage value, and I represents the real-time RMS current value. The phase angle is based on the zero-point drift calibration. This represents the proportion of reactive power in apparent power in a three-phase power grid.

10. The method for calculating time-varying power in a power grid according to claim 3, characterized in that, In step 6), the time-varying power of the power grid includes the real-time apparent power S, which is calculated according to the following formula: S = V × I; In the formula, S is the apparent power of the power grid, V is the real-time effective value of the voltage, and I is the real-time effective value of the current.

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