Remote calibration method and system for electric energy meter

Abstract

The invention relates to the technical field of electrical variable measurement, and discloses a remote calibration method and system for an electric energy meter, and the method comprises the steps: collecting load current data, calculating the fluctuation ratio of load current, and judging whether a calibration admission condition is satisfied or not; after the system judges that an access condition is met, accessing a new electric energy meter, monitoring voltage drop data of a contact point, performing transient variance cleaning to calculate a local voltage variance, and determining an effective calibration starting point; after the starting point is effectively calibrated, a coupling impedance model is constructed, and the real contact resistance of the wiring device is dynamically calculated; and performing true value correction on the voltage acquired by the new electric energy meter by using the true contact resistance, calculating a metering error, and judging whether the new electric energy meter is qualified or not according to the metering error. According to the invention, the influence of impedance thermal drift caused by hot plug mechanical oscillation and large current on metering can be effectively eliminated, and accurate replacement of the electric energy meter by large industrial and commercial households under the conditions of no power failure and no influence on metering is realized.

Description

Technical Field

[0001] This invention relates to the field of electrical variable measurement technology, specifically to a remote calibration method and system for an electricity meter. Background Technology

[0002] With the advancement of electricity market transactions, the accuracy of electricity metering directly affects the fairness of settlement between electricity suppliers and consumers. Especially in the electricity consumption scenarios of large industrial and commercial users, electricity meters typically handle huge amounts of electricity transactions, and even small deviations in metering error can lead to significant economic losses. Therefore, in accordance with relevant power operation and maintenance regulations, it is necessary to verify and calibrate electricity meters in operation.

[0003] To ensure the continuity of industrial production and avoid economic losses caused by power outages, current power metering and maintenance typically require the replacement and calibration of electricity meters without power interruption (i.e., continuous load operation) and without affecting metering. This is achieved by using meter replacement devices (such as non-destructive wiring devices for electricity metering) to hot-swap the new meter to be tested into the circuit. A remote calibration system is then used to compare the readings of the new meter with those of a standard to determine whether the new meter is qualified.

[0004] Existing remote calibration methods typically assume constant line impedance, failing to consider impedance drift caused by localized temperature rise of contacts under high-current loads, and neglecting the mechanical instability of the non-destructive power metering wiring device during hot-plugging. This leads to several shortcomings in practical applications: First, when maintenance personnel insert the power meter into the non-destructive power metering wiring device, the contacts experience mechanical oscillations and bounces at the moment of contact. This mechanical instability introduces transient voltage noise. Existing remote calibration methods ignore this mechanical instability; if the calibration algorithm initiates sampling at this moment, it may misinterpret the signal fluctuations caused by mechanical oscillations as grid fluctuations or metering errors, resulting in distorted initial data. Second, in high-voltage metering scenarios for large industrial and commercial users, the load current is usually large. When a large current flows through the contact points of the wiring device, significant Joule heating is generated, causing the contact temperature to rise. Since the resistivity of metallic materials increases with temperature, the actual impedance of the contact point is not constant but exhibits dynamic drift characteristics over time and with accumulated temperature. Existing calibration methods treat contact resistance as a fixed nominal value, ignoring this physical impedance thermal drift. These two types of physical errors are amplified during metering, leading to discrepancies between the calculated metering data and the actual values ​​in the initial stages of a new meter's operation. Therefore, a remote calibration method and system for electricity meters is urgently needed to address these issues. Summary of the Invention

[0005] In view of the problems in the related technologies, the present invention provides a remote calibration method for electricity meters to overcome the technical problems existing in the prior art.

[0006] To solve the aforementioned technical problem, the present invention is achieved through the following technical solution: In a first aspect, embodiments of the present invention provide a remote calibration method for an electricity meter, specifically including: collecting load current data, calculating the fluctuation rate of the load current, and determining whether the calibration access conditions are met based on the fluctuation rate of the load current; after the system determines that the calibration access conditions are met, connecting a new electricity meter and monitoring the voltage drop data at the contact point, performing transient variance cleaning on the voltage drop data to calculate the local voltage variance, and determining an effective calibration starting point; after the effective calibration starting point, calculating the mechanical component of the contact resistance and the local temperature rise caused by the load current, and constructing a coupling impedance model in conjunction with the resistance temperature coefficient of the wiring device contact, dynamically calculating the true contact resistance of the wiring device; using the true contact resistance to perform true value correction on the voltage collected by the new electricity meter, calculating the metering error based on the corrected true voltage value, and determining whether the new electricity meter is qualified based on the metering error.

[0007] In a preferred embodiment of the remote calibration method for the energy meter described in this invention, the formula for calculating the fluctuation rate of the load current is as follows: In the formula, The fluctuation rate of the load current. The length of the sliding time window. Indicates the current moment. Represents the integral variable. for The load current at any given time.

[0008] As a preferred embodiment of the remote calibration method for the energy meter described in this invention, the step of determining whether the calibration access conditions are met based on the fluctuation rate of the load current includes: setting a fluctuation threshold. and the effective range of load current ;like ,and Load current at any moment If the access conditions are met, the new electricity meter can be connected; if or The criteria for admission were not met.

[0009] In a preferred embodiment of the remote calibration method for the energy meter described in this invention, the formula for calculating the local voltage variance is as follows: In the formula, For local voltage variance, For the first The instantaneous voltage drop sampled at each sampling point This represents the average voltage drop within the current window. To detect the slice window.

[0010] As a preferred embodiment of the remote calibration method for the electricity meter described in this invention, determining the effective calibration starting point includes: setting a contact stability threshold. ,like If it is determined to be mechanical jitter, the data is discarded; if The system is determined to be in stable contact, and the current moment is locked as the effective calibration start point.

[0011] In a preferred embodiment of the remote calibration method for the energy meter described in this invention, the formula for calculating the mechanical component of the contact resistance is as follows: ; In the formula, For a moment The mechanical component of contact resistance, For steady-state resistance, The initial contact resistance, It is an exponential decay factor. For the current moment, The time when the new electricity meter is inserted. is the mechanical relaxation constant.

[0012] In a preferred embodiment of the remote calibration method for the energy meter described in this invention, the formula for calculating the local temperature rise is as follows: In the formula, for The local temperature rise at the contact point at any given moment. The heat capacity conversion coefficient of the wiring device. It is the heat dissipation attenuation factor. This is the heat dissipation time constant.

[0013] In a preferred embodiment of the remote calibration method for the energy meter described in this invention, the formula for calculating the actual contact resistance is as follows: ; In the formula, For a moment The actual contact resistance value, The ambient temperature inside the electricity meter. For standard reference temperature, This refers to the temperature coefficient of resistance of the contact components in the wiring device.

[0014] As a preferred embodiment of the remote calibration method for the electricity meter described in this invention, the step of calculating the metering error based on the corrected true voltage value includes: ; ; In the formula, This is the corrected true voltage value. Based on actual contact resistance The voltage collected by the new electricity meter, For the metering error of the new electricity meter, This represents the cumulative energy value of the new energy meter after impedance compensation within the calibration time window. The standard electrical energy value is measured by a standard testing instrument.

[0015] Secondly, embodiments of the present invention provide a remote calibration system for an electricity meter, comprising: an access discrimination module for collecting load current data and calculating fluctuation rate to determine whether calibration access conditions are met; a data cleaning module for monitoring voltage drop data when the electricity meter is connected and using local voltage variance to remove mechanical jitter data; an impedance calculation module for constructing a coupling impedance model based on mechanical relaxation components and current thermal effects, and calculating the real-time contact resistance of the wiring device; and a calibration decision module for correcting the true voltage value based on the real-time contact resistance, calculating the metering error, and determining whether the new electricity meter is qualified.

[0016] The present invention has the following beneficial effects: 1. This invention, by introducing the calculation of load current fluctuation rate, can capture the instantaneous rate of change of current and transform the absolute change into a relative indicator reflecting the true degree of stability. By evaluating the fluctuating energy within a sliding time window, it identifies the time periods when the grid load is in a linear steady state, thereby avoiding calibration during periods of severe load fluctuation. This mechanism helps prevent the misjudgment of grid-side load disturbances as metering deviations, thus ensuring the authenticity and availability of the remote calibration data source.

[0017] 2. This invention addresses the mechanical bounce problem caused by hot-swapping operations during uninterrupted meter replacement. It utilizes transient variance cleaning technology to process the voltage drop data at the moment of contact. By calculating the local voltage variance and comparing it with a contact stability threshold, transient noise caused by mechanical vibration of the contact components is identified and eliminated. This ensures that subsequent impedance analysis and error correction are based on a stable physical contact, resolving the problem of voltage sampling distortion caused by unstable mechanical contact.

[0018] 3. This invention constructs a coupled impedance model that includes a mechanical relaxation component and a thermal effect factor, reproducing the dynamic change process of the contact resistance of the wiring device during the initial stage of meter replacement. Especially for high-current scenarios in large industrial and commercial applications, it can calculate in real time the local temperature rise caused by the current thermal effect and the resulting impedance drift, thereby quantifying and eliminating non-nominal impedance errors introduced by hardware physical characteristics. This method overcomes the shortcomings of traditional solutions that treat contact resistance as a fixed value, helping to eliminate the interference of the wiring device's own voltage drop on metering calibration.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, the drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the electricity meter replacement operation provided by the present invention.

[0022] Figure 2 The present invention provides a flowchart of a remote calibration method for an electricity meter.

[0023] Figure 3 This is a schematic diagram of a remote calibration system for an electricity meter provided by the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 In electricity metering operation and maintenance, especially for electricity meters used by large industrial and commercial users, to ensure fair settlement, it is necessary to replace and calibrate electricity meters using wiring devices without interrupting power (i.e., continuous load operation) and without affecting metering. However, existing remote calibration methods often overlook the mechanical vibrations generated by the wiring device during hot-swapping operations and the impedance drift caused by local temperature rise of contacts under high current loads. These minute errors at the physical level are amplified during metering, leading to deviations in metering data during the initial commissioning of new meters.

[0026] To solve the above technical problems, such as Figure 2 As shown, Embodiment 1 of the present invention provides a remote calibration method for an electricity meter. Specific Embodiment 1 takes an electricity metering upgrade scenario in an industrial park as an example: Figure 1 As shown, a non-destructive wiring device for electricity metering (model ZDHB-WS-01, with copper-plated silver contacts) is deployed on site. Maintenance personnel need to replace the old electricity meter (meter 1) with the new electricity meter (meter 2) without interrupting power or affecting metering.

[0027] In the specific implementation of Example 1: First, load current data is collected, the fluctuation rate of the load current is calculated, and the calibration access conditions are determined based on the fluctuation rate of the load current. This method quantifies the stability of the load by introducing the first derivative of the load current with respect to time and combining it with the root mean square algorithm, avoiding non-metering errors introduced by load fluctuations, and preventing the load disturbance on the grid side from being misjudged as metering deviation of the electricity meter, thereby ensuring the authenticity and usability of subsequent calibration data. Second, after the system determines that the access conditions are met, a new electricity meter is connected, and the voltage drop data at the contact point is monitored. The voltage drop data is then subjected to transient variance cleaning to calculate the local voltage variance and determine the effective calibration starting point. This method uses a transient variance cleaning algorithm to eliminate mechanical bounce noise caused by hot-plugging operations on a time scale, ensuring that subsequent impedance modeling and error correction are based on stable physical contact, which helps to prevent voltage sampling distortion caused by mechanical vibration of the contact parts from affecting the final calibration accuracy. Then, after effectively calibrating the starting point, the mechanical component of the contact resistance and the local temperature rise caused by the load current are calculated. Combined with the temperature coefficient of resistance of the wiring device contacts, a coupling impedance model is constructed to dynamically calculate the true contact resistance of the wiring device. This method, through mathematical modeling, reproduces the dynamic impedance drift process of the wiring device under the dual physical effects of mechanical springback and current-induced heating during the initial hot-plugging stage. It quantifies the non-nominal impedance error introduced by the physical characteristics of the contacts, thereby avoiding misjudging the physical voltage drop generated by the hardware as a metering deviation. This provides crucial correction parameters for subsequently eliminating system errors and restoring the true metering performance of the electricity meter. Finally, the voltage collected by the new electricity meter is corrected using the true contact resistance. The metering error is calculated based on the corrected voltage true value, and the new electricity meter is judged to be qualified based on the metering error. This method accepts the metering performance of the new electricity meter based on the corrected data. Its technical effect is to eliminate the interference of the contact voltage drop of the wiring device on precise metering, ensuring the accuracy of decision-making, thereby enabling large industrial and commercial users to accurately replace electricity meters without power outages or affecting metering.

[0028] Furthermore, to better illustrate the technical solution of Embodiment 1 of the present invention, a detailed description of the remote calibration method for electricity meters is provided, specifically including the following: S1. Perform pre-exchange form preparation and access status determination, which includes the following sub-steps: S11. First, the maintenance personnel connect the standard calibrator to the calibrator interface of the wiring device. The system collects the load current sequence through meter 1. sampling frequency The frequency is at least 500Hz (preferably 1kHz-2kHz). The field terminal locally buffers the acquired raw data and performs low-pass filtering to remove high-frequency sampling noise.

[0029] S12, System calculates the fluctuation rate of load current. This is used to determine whether the current operating conditions are suitable for meter calibration. The specific formula is as follows: In the formula, This represents the fluctuation rate of the load current. The smaller the value, the smoother the current waveform and the more stable the load. The larger the value, the more drastic the current changes. Connecting a new meter in this case will cause the calibration data to be distorted. The length of the sliding time window; Indicates the current time; for Load current at any given time Represents the integral variable; The first derivative of the current with respect to time represents the rate of change of the current. This formula captures the instantaneous rate of change of the current by introducing the first derivative of the load current with respect to time, and normalizes it by combining it with the reciprocal of the instantaneous current. This transforms the absolute change affected by the load base into a relative volatility that reflects the true stability. At the same time, the root mean square algorithm is used to integrate and smooth the energy of this relative volatility within a sliding time window. This not only effectively shields against occasional signal glitches but also provides a sensitive quantification of load stability under different current magnitudes on a uniform scale, ensuring that remote calibration is triggered only when the load is in a linear steady state with an extremely low relative rate of change.

[0030] S13. Admission Status Determination: Set Fluctuation Threshold The fluctuation rate of the load current With fluctuation threshold In comparison, specifically: like ,and If the access conditions are met, the remote platform will send an instruction to the field terminal allowing access to meter 2. like or The criteria for admission were not met. It is important to note that when load current is detected... Less than If the conditions for inclusion are not met, the volatility calculation is skipped.

[0031] In this embodiment 1, , Select the rated continuous operating current specified in the device instruction manual, and refer to the specifications of the device used in this embodiment (rated current 1A, 20A) to set. , .

[0032] Fluctuation threshold The settings need to take into account the accuracy class and allowable error of the electricity meters to be put into operation. Maximum synchronization time difference of the system And the impact of typical load fluctuations on energy integration error. The fluctuation rate of load current can be established through simulation analysis or experimental calibration. The mapping relationship between the threshold and the maximum possible additional measurement error is used to determine a conservative threshold. In this embodiment, to meet the calibration requirements of a 0.2s-class energy meter, a comprehensive evaluation and setting are performed. for s -1 .

[0033] exist Based on this, this embodiment sets the system sampling interval to 0.01s and the sliding time window... Within a 10-second window, the system selects an arbitrary microscopic sampling moment to measure an instantaneous current of 10.000 A, and the instantaneous current measured at the next moment is 10.001 A. The first derivative of the current with respect to time is then calculated. Substituting into the formula and integrating, we obtain... Approximately 1.0%s -1 Because 1.0% is less than And the instantaneous current is 10.000A. Therefore, the system determines that the admission conditions are met.

[0034] In the example above, the system calculates the load current fluctuation rate based on the collected real-time load current data. Furthermore, if the instantaneous current is within the effective range, the access conditions are deemed met, and an access permission command is generated. This step aims to identify suitable time periods for remote calibration by quantifying the stability of the load. This method helps to avoid non-metering errors introduced by drastic load fluctuations and prevents the misjudgment of load disturbances on the grid side as metering deviations, thereby ensuring the authenticity and availability of subsequent calibration data.

[0035] S2. After the system determines that the access conditions are met, it performs new table contact impedance compensation, which includes the following sub-steps: S21. After receiving the instruction, the maintenance personnel insert the meter 2 to be put into operation into the meter 2 interface of the device. Because the wiring device supports hot-swapping, mechanical vibration will occur at the moment of contact between the silver-plated copper contacts. The system monitors the level changes of the auxiliary nodes of the device and marks the insertion time of meter 2. .

[0036] S22, System for insertion time The subsequent voltage drop data underwent transient variance cleaning, and the local voltage variance was calculated. : In the formula, For the first The instantaneous voltage drop sampling value of each sampling point represents the actual voltage drop generated when the current flows through the contact point between meter 2 and the wiring device at a certain instant within the detection window. It is collected in real time by the sensor. This represents the average voltage drop within the current window. The detection slice window is calculated by multiplying the sampling frequency by the window time.

[0037] S23. Set the contact stability threshold. The local voltage variance With contact stability threshold By comparison, the stability of the contact point is determined, specifically: like If this is determined to be mechanical vibration, the data is discarded, and no calibration is performed. like If the contact is deemed stable, calibration is permitted.

[0038] In this embodiment 1, the contact stability threshold The setting is based on the physical boundaries of contact resistance stability. Specifically, the maximum allowable fluctuation value of the contact resistance is set to 0.1. If the on-site load current is 10A, then the corresponding maximum allowable voltage fluctuation range is: Based on the characteristics of the normal distribution, a contact stability threshold is set. (mV) 2 This indicates the variance of the measured local voltage. A value higher than this indicates that the contact point impedance fluctuation exceeds 0.1. The physical limit is determined to be mechanical vibration.

[0039] exist (mV) 2 Based on this, the sampling frequency in this embodiment is 1kHz and the window time is 10ms, so the detection slice window... The system collected 10 instantaneous voltage values: 50.1mV, 49.9mV, 50.0mV, 50.2mV, 49.8mV, 50.1mV, 49.9mV, 50.0mV, 50.1mV, and 49.9mV. The average value was calculated. =50.0mV, calculate the value of each point relative to the mean. The squares of the deviations are summed and then divided by the detection slice window. The local voltage variance was calculated. (mV) 2 ,because Since the value is less than 1.0, the system determines that the contact state is stable within this time window, and the system will lock the current moment as the valid calibration start point. .

[0040] In the example above, the system first bases its detection on a predefined slice window. Collect discrete voltage data and calculate the arithmetic mean of this set of data. The local voltage variance is calculated by taking the average of the sum of squares of the deviations of each sampling point from the mean. for (mV) 2 Given that this value is less than the preset contact stability threshold. The system determines that the contact has stopped mechanical oscillation and reached a stable state, thus locking in the valid calibration starting point. This step aims to use a transient variance cleaning algorithm to eliminate mechanical bounce noise caused by hot-plugging operations on a time scale, ensuring that subsequent impedance modeling and error correction are based on stable physical contact, and helping to prevent voltage sampling distortion caused by contact mechanical vibration from affecting the final calibration accuracy.

[0041] S3. When the system determines that the contact state is stable within the time window, the system constructs a coupling impedance model and dynamically calculates the real-time contact resistance of the wiring device. To eliminate physical errors in the wiring device itself, the following sub-steps are included: S31. When meter 2 is first inserted, the spring pressure and plating deformation require time to stabilize. Calculate the mechanical component of the contact resistance. Its expression is: ; In the formula, For a moment The mechanical component of contact resistance represents the contact resistance value determined solely by contact pressure, surface roughness, and degree of engagement, without considering the influence of temperature. The steady-state resistance represents the final ideal resistance value reached at the contact point after the spring is fully compressed and the mechanical deformation is complete. It is obtained by referring to the nominal specifications of the wiring device; in this embodiment, it is 5. ; The initial contact resistance is given at the instant meter 2 is inserted. At this moment, because the spring is not fully attached and the contact surface is only a point contact rather than a surface contact, the contact area is the smallest and the resistance is the largest. It is an exponential decay factor, characterizing the decay over time. As the value increases, this item rapidly decreases from 1 to near 0; Let be the mechanical relaxation constant. This formula, by introducing a mechanical relaxation component based on exponential decay, can reproduce the nonlinear variation characteristics of contact resistance in the initial stage of meter replacement, unlike traditional methods that directly use constants. In comparison, this method effectively corrects the measurement error caused by unstable contact in the initial stage of meter replacement (the first few seconds to tens of seconds), which helps to improve calibration accuracy.

[0042] In this embodiment 1, the initial contact impedance and mechanical relaxation constant The backfitting method is used to obtain the data. Specifically, the system selects an effective calibration starting point. The following consecutive sampling points (e.g., selecting) to within the time period There are 10 data points, of which The sampling time must be shorter than the timescale in which the thermal effect becomes significant (e.g., within 0.5 seconds). For each sampling point... The instantaneous contact resistance is calculated based on the real-time collected voltage difference and current. Construct the objective function: In the formula, The objective function value is given; then, the least squares method is used to iteratively solve the objective function, thereby simultaneously calculating the optimal initial contact impedance in reverse. and mechanical relaxation constant This method uses the initial observation values ​​to backfit the physical model, thereby obtaining a smooth impedance curve that conforms to physical laws and avoiding noise interference in subsequent true value correction.

[0043] S32. Considering that a large current flowing through the contact point will cause a local temperature rise, even if the ambient temperature remains unchanged, the contact point temperature will still rise. Therefore, the system calculates the local temperature rise based on the integration of historical load current. : In the formula, for The local temperature rise at the contact point at any given time represents the portion of the contact point's temperature that is higher than the ambient temperature. The heat capacity conversion coefficient of the wiring device; The heat dissipation decay factor describes the process of heat naturally dissipating over time. The heat dissipation time constant is a physical quantity that describes how quickly a wiring device dissipates heat.

[0044] In this embodiment 1, the heat dissipation time constant The temperature rise was measured through a natural cooling test of the device. Specifically, at an ambient temperature of 25°C, the device was heated to a steady state and then powered off, and the temperature rise curve was monitored. According to Newton's law of cooling, the temperature rise decay follows the formula... Therefore, when the temperature rise decreases to the initial value... When the temperature reaches approximately 36.8%, the time taken for this process is recorded, and this time is defined as the heat dissipation time constant. For the wiring device of model ZDHB-WS-01, the actual measured time was 120 seconds, therefore, it was set to... .

[0045] In this embodiment 1, the heat capacity conversion coefficient The steady-state thermal equilibrium test was conducted, specifically: a constant current of 10A was applied to the device, and the steady-state temperature rise was measured. Approximately 6℃, based on the limiting equilibrium formula The reverse calculation yields Approximately 0.0005 .

[0046] S33. Constructing a coupling impedance model: The temperature coefficient of resistance of the system's connection device contacts (silver-plated copper). ,calculate Real contact resistance at any moment : ; In the formula, For a moment The actual contact resistance value; The ambient temperature inside the electricity meter is obtained in real time by a temperature sensor built into the wiring device. The standard reference temperature is the steady-state resistance. (5) The laboratory temperature condition at which the resistance temperature coefficient is defined is 25°C in this embodiment; Depending on the contact material, the wiring device contacts in this embodiment are copper plated with silver. Current mainly flows through the silver plating layer. Silver's temperature coefficient of resistance is approximately 0.0038 Ω / ℃. Therefore, the setting... .

[0047] In this embodiment 1, the nominal contact resistance of the wiring device is... =5 The initial non-steady-state resistance is set to be slightly loose upon insertion. Mechanical relaxation constant The value is 2.0, and the ambient temperature is obtained. At 30℃, the load current was measured 0.5 seconds into the calibration process. Given an A value of 18A, the mechanical component of the contact resistance is calculated. Local temperature rise Approximately 0.08℃ Calculate the final actual contact resistance At this point, the actual impedance is higher than the nominal 5. Without compensation, an 18A current will be generated. Additional voltage drop error.

[0048] In the example above, the system, based on the constructed coupling impedance model, calculates the mechanical relaxation component. By combining the thermal effect factor, which includes local temperature rise, the actual contact resistance at the current moment can be calculated. for This step aims to reproduce the dynamic impedance drift process of the wiring device under the dual physical effects of mechanical springback and current-induced heating during the initial hot-plugging stage through mathematical modeling. It quantifies the non-nominal impedance error introduced by the physical characteristics of the contact components, thereby avoiding misjudging the physical voltage drop generated by the hardware as the metering deviation of the electricity meter. This provides key correction parameters for subsequent elimination of system errors and restoration of the true metering performance of the electricity meter.

[0049] S4. The system utilizes the calculated actual contact resistance. The voltage collected by meter 2 The process involves truth value correction, calculation of voltage divider error in the wiring device, and evaluation and decision-making based on the voltage divider error. Specifically, this includes the following steps: S41. Calculate the corrected true voltage value. It is represented as: .

[0050] S42, Based on the corrected true voltage value Calculate the measurement error of meter 2 using data from the standard calibrator. : ; ; In the formula, , These are the start and end times of the calibration time window, respectively. This represents the cumulative energy value of meter 2 after impedance compensation within the calibration time window; The standard electrical energy value is measured by a standard testing instrument.

[0051] S43. Set error threshold If the measurement error The system determines that meter 2 is qualified, and the remote platform issues a command to allow meter replacement. The maintenance personnel complete the meter replacement and adjust the load fluctuation rate within the calibration time window. Actual contact resistance and measurement error Package and generate an evaluation report and upload it; if The system determines that meter 2 is unqualified, and the remote calibration platform immediately issues an instruction to prohibit meter replacement. At this time, billing will still use meter 1 to ensure that the settlement is not affected by the unqualified new meter. It is recommended to replace the current meter 2 with a new one and repeat the above remote calibration steps.

[0052] For example, error threshold According to the "Verification Procedure for Electronic Energy Meters" (JJG596-2012), this procedure specifies the basic error limit for 0.2s-class energy meters within their main operating range. Therefore, in this embodiment, the error threshold is... Set to 0.2%.

[0053] In this embodiment 1, at 0.5s during the calibration process, meter 2 measures the voltage. The voltage measured by the standard calibrator is 57.58V. The voltage is 57.70V. Calculate the true voltage value. At this point, the corrected voltage of meter 2, 57.69V, is highly consistent with the standard value of 57.70V. After 60 seconds of continuous integration calculation, the system calculates the measurement error of meter 2. ,because If the error is less than 0.2% of the error threshold, the system determines that the current meter 2 is qualified, and then remotely instructs the maintenance personnel to replace the meter.

[0054] In the example above, the system uses the true voltage value after impedance compensation to perform energy integration calculation to obtain the metering error of meter 2. for Given that the value is less than the preset error threshold of 0.2%, the system ultimately determines that the current meter 2 is qualified and executes the meter replacement command. This step aims to conduct a final acceptance test on the metering performance of the new meter based on the corrected data. Its technical effect is to eliminate the interference of the contact voltage drop of the wiring device on the electricity metering, ensure the accuracy of the decision, and thus enable large industrial and commercial users to accurately replace electricity meters without power outages and without affecting metering.

[0055] Example 2 As a second embodiment of the present invention, such as Figure 3 As shown in Example 1, this example also discloses a remote calibration system for an electricity meter, which specifically includes: an access discrimination module, a data cleaning module, an impedance calculation module, and a calibration decision module.

[0056] The system also includes a multi-point voltage acquisition unit, which is used to acquire the voltage at the inlet of the wiring device and the input of the energy meter respectively, so as to obtain contact point voltage drop data.

[0057] The admission discrimination module is used to collect load current data in real time, calculate the fluctuation rate of the load current using a sliding time window algorithm, and compare the fluctuation rate and instantaneous current value with preset admission conditions to identify a linear steady-state time window suitable for remote calibration, thereby avoiding non-measurable errors caused by drastic fluctuations at the load end. The data cleaning module is used to monitor the voltage drop data stream at the contact point in real time when the electricity meter to be put into operation is connected to the wiring device. It uses the local voltage variance algorithm to identify and remove mechanical jitter data caused by hot-plugging operation, and locks the effective calibration starting point after the contact state is stable to prevent the sampling data from being distorted. The impedance calculation module is used to construct a coupling impedance model based on the mechanical relaxation principle and the current thermal effect, calculate the mechanical attenuation component of the contact resistance according to the connection time, and calculate the local temperature rise of the contact point by combining the historical load current integration, so as to dynamically calculate the real-time contact resistance of the wiring device under the current physical environment, so as to eliminate the physical error of the wiring device itself. The calibration decision module is used to correct the voltage data collected by the energy meter to be put into operation using the calculated real-time contact resistance, calculate the metering error based on the corrected voltage true value and standard data, and determine whether the energy meter is qualified according to the preset error threshold, and generate the final evaluation report or meter replacement instruction.

[0058] In the specific implementation of Implementation 2 above, firstly, the system quantitatively assesses the stability of the grid load through the access judgment module. The calibration process is only initiated when the current fluctuation rate is below a set threshold. This method prevents load disturbances on the grid side from being misjudged as metering deviations, ensuring the reliability of the data source. Secondly, through the data cleaning module, the system performs transient variance analysis on the voltage signal at the moment of hot-plugging, automatically filtering out noise caused by spring oscillation. This method utilizes statistical characteristics to identify the stability of physical contacts, solving the problem of traditional methods struggling to determine the calibration zero point. Then, through the impedance calculation module, the system calculates the impedance drift caused by contact temperature rise in real time for high-current scenarios of large industrial and commercial users. This method reproduces the dynamic change process of contact resistance through mathematical modeling, eliminating non-nominal errors introduced by hardware physical characteristics. Finally, the calibration decision module accepts the new electricity meter based on the true voltage value after eliminating physical errors. This method achieves high-precision calibration under non-destructive wiring conditions, ensuring fairness in settlement between power suppliers and users and meeting the compliance requirements for uninterrupted meter replacement in power metering operation and maintenance.

[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The preferred embodiments of the invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A remote calibration method for an electricity meter, characterized in that, include: Collect load current data, calculate the load current volatility, and determine whether the calibration admission conditions are met based on the load current volatility. After the system determines that the calibration access conditions are met, it connects a new energy meter and monitors the voltage drop data at the contact point. It then performs transient variance cleaning on the voltage drop data to calculate the local voltage variance and determines the effective calibration starting point. After effectively calibrating the starting point, the mechanical component of the contact resistance and the local temperature rise caused by the load current are calculated. Combined with the temperature coefficient of resistance of the wiring device contact, a coupling impedance model is constructed to dynamically calculate the actual contact resistance of the wiring device. The voltage collected by the new energy meter is corrected using the actual contact resistance. The metering error is calculated based on the corrected voltage true value, and the new energy meter is determined to be qualified based on the metering error.

2. The remote calibration method for an electricity meter according to claim 1, characterized in that, The formula for calculating the fluctuation rate of the load current is: In the formula, The fluctuation rate of the load current. The length of the sliding time window. Indicates the current moment. Represents the integral variable. for The load current at any given time.

3. The remote calibration method for an electricity meter according to claim 2, characterized in that, The determination of whether the load current-based volatility meets the calibration admission criteria includes: setting a volatility threshold. and the effective range of load current ;like ,and Load current at any moment If the access conditions are met, the new electricity meter can be connected; if or The criteria for admission were not met.

4. The remote calibration method for an electricity meter according to claim 1, characterized in that, The formula for calculating the local voltage variance is: In the formula, For local voltage variance, For the first The instantaneous voltage drop sampled at each sampling point This represents the average voltage drop within the current window. To detect the slice window.

5. The remote calibration method for an electricity meter according to claim 4, characterized in that, Determining the effective calibration starting point includes: setting a contact stability threshold. ,like If it is determined to be mechanical jitter, the data is discarded; if The system is determined to be in stable contact, and the current moment is locked as the effective calibration start point.

6. The remote calibration method for an electricity meter according to claim 1, characterized in that, The formula for calculating the mechanical component of the contact resistance is: ； In the formula, For a moment The mechanical component of contact resistance, For steady-state resistance, The initial contact resistance, It is an exponential decay factor. For the current moment, The time when the new electricity meter is inserted. is the mechanical relaxation constant.

7. The remote calibration method for an electricity meter according to claim 6, characterized in that, The formula for calculating the local temperature rise is: In the formula, for The local temperature rise at the contact point at any given moment. The heat capacity conversion coefficient of the wiring device. It is the heat dissipation attenuation factor. This is the heat dissipation time constant.

8. The remote calibration method for an electricity meter according to claim 7, characterized in that, The formula for calculating the actual contact resistance is: ； In the formula, For a moment The actual contact resistance value, The ambient temperature inside the electricity meter. For standard reference temperature, This refers to the temperature coefficient of resistance of the contact components in the wiring device.

9. The remote calibration method for an electricity meter according to claim 8, characterized in that, The calculation of measurement error based on the corrected true voltage value includes: ； ； In the formula, This is the corrected true voltage value. Based on actual contact resistance The voltage collected by the new electricity meter, For the metering error of the new electricity meter, This represents the cumulative energy value of the new energy meter after impedance compensation within the calibration time window. The standard electrical energy value is measured by a standard testing instrument.

10. A remote calibration system for an electricity meter, used to execute the remote calibration method for an electricity meter according to any one of claims 1 to 9, characterized in that, include: The admission discrimination module is used to collect load current data and calculate volatility to determine whether the calibration admission conditions are met. The data cleaning module is used to monitor voltage drop data when the electricity meter is connected and to remove mechanical jitter data by using local voltage variance; The impedance calculation module is used to construct a coupling impedance model based on mechanical relaxation components and current thermal effects, and to calculate the real-time contact resistance of the wiring device. The calibration decision module is used to correct the true voltage value based on the real-time contact resistance, calculate the metering error, and determine whether the new energy meter is qualified.

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