Automatic multi-point calibration method for electrical parameter measurement

Abstract

The invention discloses an electrical parameter metering automatic multi-point calibration method, which comprises the following steps of: firstly, selecting electrical parameter calibration points in an electrical parameter measurement range of equipment to be calibrated in a balanced manner, including a voltage calibration point and a current calibration point; meanwhile, temperature points are selected in a balanced mode in the working temperature range of the to-be-calibrated equipment, and the to-be-calibrated equipment is placed in the selected temperature environment to be calibrated. According to the method provided by the invention, through multi-point calibration and a calibration mode of considering an environment temperature factor, a measurement nonlinear error can be effectively corrected, the calibration precision is improved, high accuracy of electrical parameter metering can be kept in different temperature environments, the environment adaptability of equipment is enhanced, and the measurement accuracy is improved. The method can be widely applied to intelligent street lamps, intelligent electric boxes and other products with high requirements for the electric parameter metering precision, and is beneficial to reducing electric energy trade disputes, avoiding equipment protection misoperation, improving the accuracy of energy efficiency evaluation and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical parameter measurement, and in particular to an automatic multi-point calibration method for electrical parameter measurement. Background Art

[0002] Electrical parameter measurement (including voltage, current, power, and energy) is a core technology for power systems, industrial automation, renewable energy generation, smart grids, and high-precision test equipment. With the increasing complexity of power electronics and the increasing demands for measurement accuracy, traditional calibration methods are no longer able to meet modern measurement needs, and more efficient and intelligent automatic calibration technologies are urgently needed. Accurate measurement of electrical parameters directly impacts power system stability, industrial equipment energy efficiency management, and renewable energy generation metering. Excessive measurement errors can lead to power trade disputes (such as smart meter errors affecting billing), equipment protection misoperation (such as inaccurate overcurrent detection), and distorted energy efficiency assessments (such as the inability to quantify the effects of energy-saving renovations).

[0003] The current method for electrical parameter measurement is single-point calibration. This involves using a standard source (such as the Star Dragon Technology XL-801) to output a reference signal (e.g., voltage 250V, current 4A, power factor 1), recording the measured values ​​of the device under test (e.g., a smart street light controller or smart electrical box controller), and finally calculating the electrical parameter gain values ​​(e.g., voltage gain, current gain, power gain, energy gain, etc.) to achieve the purpose of calibrating the electrical parameter measurement. However, because this single-point calibration method only calibrates the measuring device under specific test conditions (e.g., fixed voltage, current, or power), it only corrects for errors near that point and does not cover the entire measurement range. While this method is simple and easy to implement, it suffers from the following key issues in practical applications. First, it cannot correct for measurement nonlinearity. While the error is small near the calibration point, it may increase significantly in other ranges (e.g., low voltage or high current). For example, a voltmeter with an error of ±0.1% at the 10V calibration point may have an error of ±1% at 1V. Second, it suffers from poor environmental adaptability. Single-point calibration is usually performed in a constant environment (such as a constant temperature in a laboratory) without considering the impact of temperature changes on measurement accuracy. The sensitivity of current sensors (such as Hall elements) changes with temperature, and single-point calibration cannot dynamically compensate for this. Summary of the Invention

[0004] In view of the above shortcomings, the present invention aims to provide an automatic multi-point calibration method for electrical parameter measurement that uses multi-point calibration and combines ambient temperature to calibrate the device under test, corrects measurement nonlinear errors, and has strong environmental adaptability.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0006] An automatic multi-point calibration method for electrical parameter measurement comprises the following steps:

[0007] Place the device to be calibrated in the selected temperature environment and connect the device according to the set connection lines;

[0008] A plurality of electrical parameter calibration points are evenly selected within the electrical parameter measurement range of the device to be calibrated, including voltage calibration points and current calibration points;

[0009] Select multiple temperature points evenly within the operating temperature range of the device to be calibrated;

[0010] An automated script is used to control the source meter to sequentially output the voltage and current corresponding to each electrical parameter calibration point, so that the device to be calibrated starts the internal calibration procedure for calibration and stores the parameter gain of each electrical parameter calibration point.

[0011] When the equipment is used on site, the original values ​​of the electrical parameters are read, compared with the electrical parameter calibration points, and the parameter gains corresponding to the electrical parameter calibration points are extracted to calculate the actual measurement values.

[0012] As a preferred solution of the present invention, the voltage calibration points are selected by the following method: several points within the voltage range of the device to be calibrated are evenly selected, where voltage U0 is the minimum value of the voltage measured by the device to be calibrated, voltage U0+nX is the maximum value of the voltage measured by the device to be calibrated, the voltage unit is V, n and X are both positive integers, and X is the step value for selecting the voltage calibration points.

[0013] As a preferred solution of the present invention, the current calibration point is selected by the following method: several points within the current measurement range of the device to be calibrated are evenly selected, where the current I0 is the minimum value of the current measured by the device to be calibrated, the current I0+nY is the maximum value of the current measured by the device to be calibrated, the voltage unit is A, n and Y are both positive integers, and Y is the step value selected for the current calibration point.

[0014] As a preferred solution of the present invention, the temperature points are selected by the following method: several points within the operating temperature range of the device to be calibrated are evenly selected, where temperature T0 is the minimum operating temperature of the device to be calibrated, temperature T0+nZ is the maximum operating temperature of the device to be calibrated, the temperature unit is ℃, n and Z are both positive integers, and Z is the step value for selecting the temperature points.

[0015] As a preferred solution of the present invention, the selected voltage calibration points, current calibration points, and temperature points of the environment in which the equipment is calibrated are combined to form a multi-point calibration table.

[0016] As a preferred solution of the present invention, at the beginning of calibration, the device to be calibrated is placed in a constant temperature box and the temperature is set.

[0017] The beneficial effects of the present invention are as follows: the method provided by the present invention can effectively correct measurement nonlinear errors and improve calibration accuracy through multi-point calibration and calibration methods that take ambient temperature factors into consideration, so that electrical parameter measurement can maintain high accuracy under different temperature environments, thereby enhancing the environmental adaptability of the equipment. It can be widely used in products such as smart street lamps and smart electrical boxes that have high requirements for electrical parameter measurement accuracy, helping to reduce electricity trade disputes, avoid equipment protection malfunctions, and improve the accuracy of energy efficiency evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the connection circuits when the device to be calibrated is calibrated.

[0019] Figure 2 This is a schematic diagram of the voltage calibration point selection principle of the device to be calibrated of the present invention.

[0020] Figure 3 Schematic diagram of current calibration point selection for the device to be calibrated of the present invention.

[0021] Figure 4 The present invention is a schematic diagram of the temperature selection principle of the environment in which the device to be calibrated is located during calibration.

[0022] Figure 5 This is a multi-point calibration flow chart of the present invention. DETAILED DESCRIPTION

[0023] Example: See Figure 1 and Figure 5 , an embodiment of the present invention provides an automatic multi-point calibration method for electrical parameter measurement, which includes the following steps:

[0024] Place the device to be calibrated in the selected temperature environment and connect the device according to the set connection lines; the connection lines are as follows: Figure 1 As shown in the figure, connect the computer and the standard source meter to the mains power supply (220VAC). The computer is connected to the device to be calibrated and the standard source meter via a serial cable. The standard source meter is connected to the device to be calibrated via voltage and current output cables.

[0025] A plurality of electrical parameter calibration points are evenly selected within the electrical parameter measurement range of the device to be calibrated, including voltage calibration points and current calibration points;

[0026] Preferably, the voltage calibration point is selected by the following method: Figure 2 , evenly select several points within the voltage range of the device to be calibrated, where voltage U0 is the minimum value of the voltage measured by the device to be calibrated, voltage U0+nX is the maximum value of the voltage measured by the device to be calibrated, the voltage unit is V (volt), n and X are both positive integers, and X is the step value selected for the voltage calibration point.

[0027] The current calibration point is preferably selected by the following method: Figure 3 , evenly select several points within the current range of the device to be calibrated, where current I0 is the minimum current measured by the device to be calibrated, current I0+nY is the maximum current measured by the device to be calibrated, the voltage unit is A (ampere), n and Y are both positive integers, and Y is the step value selected for the current calibration point.

[0028] Multiple temperature points are evenly selected within the operating temperature range of the device to be calibrated; preferably, the temperature points are selected using the following method: Figure 4 , evenly select several points within the operating temperature range of the device to be calibrated, where temperature T0 is the minimum operating temperature of the device to be calibrated, temperature T0+nZ is the maximum operating temperature of the device to be calibrated, the temperature unit is ℃ (Celsius), n and Z are both positive integers, and Z is the step value for selecting the temperature points.

[0029] The selected voltage calibration points, current calibration points, and temperature points of the environment in which the equipment is calibrated are combined to form a multi-point calibration table, as shown in Table 1.

[0030] Table 1

[0031] Calibration point 1 Calibration point 2 Calibration point 3 …… Calibration point n Voltage 1 Voltage 2 Voltage 3 …… Voltage n Current 1 Current 2 Current 3 …… Current n Temperature 1 Temperature 2 Temperature 3 …… Temperature n

[0032] The standard source meter is controlled by an automated script to sequentially output the voltage and current corresponding to each electrical parameter calibration point, so that the device to be calibrated starts the internal calibration program for calibration and stores the parameter gain of each electrical parameter calibration point. When the device is used on site, the original value of the electrical parameter is read and compared with the electrical parameter calibration point, and the parameter gain corresponding to the electrical parameter calibration point is extracted to calculate the actual measurement value. For details, see Figure 5 At the beginning of calibration, first place the device to be calibrated in a constant temperature box and follow Figure 1 Connect all devices with the connection lines, then set the constant temperature box to temperature 1. After the constant temperature box stabilizes at temperature 1 for a certain period of time, start the automation script 1. The script will automatically send the standard source meter setting instructions. The standard source meter sets the voltage 1 and current 1 outputs. At this time, the device to be calibrated is powered, and the script sends the calibration instructions to the device to be calibrated. The device starts the internal calibration function. After the calibration is completed, the device automatically stores the gains of the various parameters at calibration point 1. Then, the calibration process from calibration point 2 to calibration point n is carried out in sequence. After the calibration of calibration point n is completed, the calibration of the device is completed. When the device is used on site, the original values ​​of each electrical parameter will be read first, and then compared with each calibration point to see which calibration point is closest. The gains of the various parameters stored in the device for this calibration point are extracted. The actual measurement value is equal to the original value multiplied by the gain.

[0033] The following example illustrates this using a Hongzhan Technology LP-80U constant temperature chamber and a Xinglong Technology XL-801 standard source meter. Calibration point 1: Temperature 1 = -20°C, Voltage 1 = 100V, Current 1 = 500mA; Calibration point 2: Temperature 2 = -20°C, Voltage 2 = 150V, Current 2 = 1A; and Calibration point n: Temperature n = 80°C, Voltage n = 300V, Current n = 4A.

[0034] The first step is to place the street light controller in a constant temperature box.

[0035] Next, connect all equipment according to the wiring diagram. Connect the computer and the standard source meter to the mains power supply (220VAC). Connect the computer to the streetlight controller and the standard source meter via a serial cable. Connect the standard source meter to the streetlight controller via voltage and current output cables. The cables connecting the streetlight controller enter and exit through the circular hole on the side of the incubator. Finally, secure the hole with a wooden plug.

[0036] The third step is to set the thermostat temperature to temperature 1, wait for the temperature inside the thermostat to reach the set temperature, and then stabilize for 30 minutes.

[0037] The fourth step is to start the automatic calibration script 1 on the computer. First, script 1 will automatically send voltage and current setting instructions to the standard source meter through the computer serial port. After receiving the instructions, the standard source meter will automatically set the voltage 1 and current 1 outputs. Then, script 1 will automatically send a calibration start instruction to the street light controller through the computer serial port. After receiving the calibration instruction, the street light controller will automatically run the internal calibration function. After the operation is completed, the street light controller will store the electrical parameter gains in its internal flash memory and send the electrical parameter gains to the computer script 1. Script 1 will automatically determine the rationality of the electrical parameter gains. If they are reasonable, the interface will display "Calibration Point 1 Calibration Successful". If not, the interface will display "Calibration Point 1 Calibration Failed". For example, the voltage gain of calibration point 1 is 1.012345, the current gain is 1.023456, the power gain is 1.123456, the energy gain is 1.001122, the temperature gain is 1.024562, and so on.

[0038] Step 5: Repeat steps 3 and 4 to implement the calibration process for calibration point 2.

[0039] Step 6: Repeat steps 3 and 4 until the calibration process for calibration point n is completed.

[0040] According to the disclosure and teachings of the above description, those skilled in the art to which the present invention belongs may also change and modify the above-mentioned embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this description, these terms are only for convenience of description and do not constitute any limitation to the present invention. As described in the above-mentioned embodiments of the present invention, other standard methods obtained by adopting the same or similar structures are all within the scope of protection of the present invention.

Claims

1. An automatic multi-point calibration method for electrical parameter measurement, characterized in that: It includes the following steps: Place the device to be calibrated in the selected temperature environment and connect the device according to the set connection lines; A plurality of electrical parameter calibration points are evenly selected within the electrical parameter measurement range of the device to be calibrated, including voltage calibration points and current calibration points; Select multiple temperature points evenly within the operating temperature range of the device to be calibrated; An automated script is used to control the source meter to sequentially output the voltage and current corresponding to each electrical parameter calibration point, so that the device to be calibrated starts the internal calibration procedure for calibration and stores the parameter gain of each electrical parameter calibration point. When the equipment is used on site, the original values ​​of the electrical parameters are read, compared with the electrical parameter calibration points, and the parameter gains corresponding to the electrical parameter calibration points are extracted to calculate the actual measurement values.

2. The automatic multi-point calibration method for electrical parameter measurement according to claim 1, characterized in that: The voltage calibration points are selected by the following method: a number of points within the voltage range of the device to be calibrated are evenly selected, where voltage U0 is the minimum value of the voltage measured by the device to be calibrated, voltage U0+nX is the maximum value of the voltage measured by the device to be calibrated, the voltage unit is V, n and X are both positive integers, and X is the step value for selecting the voltage calibration points.

3. The automatic multi-point calibration method for electrical parameter measurement according to claim 1, characterized in that: The current calibration points are selected by the following method: several points within the current measurement range of the device to be calibrated are selected evenly, where the current I0 is the minimum value of the current measured by the device to be calibrated, the current I0+nY is the maximum value of the current measured by the device to be calibrated, the voltage unit is A, n and Y are both positive integers, and Y is the step value selected for the current calibration point.

4. The automatic multi-point calibration method for electrical parameter measurement according to claim 1, characterized in that: The temperature points are selected using the following method: several points within the operating temperature range of the device to be calibrated are evenly selected, where temperature T0 is the minimum operating temperature of the device to be calibrated, temperature T0+nZ is the maximum operating temperature of the device to be calibrated, the temperature unit is ℃, n and Z are both positive integers, and Z is the step value for selecting the temperature points.

5. The automatic multi-point calibration method for electrical parameter measurement according to any one of claims 1 to 4, characterized in that: The selected voltage calibration points, current calibration points, and temperature points of the environment in which the equipment is calibrated are combined to form a multi-point calibration table.

6. The automatic multi-point calibration method for electrical parameter measurement according to claim 1, characterized in that: At the beginning of calibration, place the device to be calibrated in the constant temperature box and set the temperature.

7. The automatic multi-point calibration method for electrical parameter measurement according to claim 1, characterized in that: The connection line is that the computer is connected to the device to be calibrated and the standard source meter through a serial port line, and the standard source meter is connected to the device to be calibrated through voltage and current output lines.

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