阅读说明：本技术 基于感应线圈的冲击电流测量装置的量值溯源方法及系统 (Magnitude tracing method and system of impulse current measuring device based on induction coil ) 是由 李文婷 龙兆芝 范佳威 胡康敏 刘少波 雷民 周峰 余也凤 于 2020-11-12 设计创作，主要内容包括：本发明公开了一种基于感应线圈的冲击电流测量装置的量值溯源方法及系统,将感应线圈和二次测量设备分开进行刻度因数的溯源,使得溯源更具操作性,溯源过程包括：利用冲击电流标准波源实现感应线圈冲击刻度因数和时间参数的溯源；利用标准工频电流互感器实现感应线圈在额定电流范围内的刻度因数线性度溯源；利用电流方波源实现感应线圈的动态特性的溯源；利用冲击电压标准波源实现二次测量设备的冲击刻度因数和时间参数的溯源；利用电压方波源实现二次测量设备的动态特性的溯源。本发明给出了冲击电流量值溯源的完整技术链条,能够为建立冲击电流标准测量系统奠定基础,同时为解决电力系统及工业生产中的冲击电流测量装置校准试验提供技术方法。(The invention discloses a magnitude traceability method and system of an impulse current measuring device based on an induction coil, which separately trace the source of a scale factor by the induction coil and a secondary measuring device, so that the traceability is more operable, and the traceability process comprises the following steps: tracing the impact scale factor and the time parameter of the induction coil by using an impact current standard wave source; the standard power frequency current transformer is utilized to realize the scale factor linearity tracing of the induction coil in the rated current range; tracing the dynamic characteristics of the induction coil by utilizing a current square wave source; tracing the impact scale factor and the time parameter of the secondary measurement equipment by using an impact voltage standard wave source; and tracing the dynamic characteristics of the secondary measurement equipment by using a voltage square wave source. The invention provides a complete technical chain for tracing the magnitude of the impulse current, can lay a foundation for establishing an impulse current standard measurement system, and provides a technical method for solving the calibration test of the impulse current measurement device in the power system and industrial production.)

1. A magnitude tracing method of an impulse current measuring device based on an induction coil is characterized in that the impulse current measuring device comprises: an induction coil and a secondary measurement device, the method comprising:

inputting an impact current signal with a preset amplitude value to the induction coil by using an impact current standard wave source, acquiring a first voltage signal output by the induction coil, and determining a first impact scale factor and a first time parameter measurement of the induction coil according to the current values and time parameters of the first voltage signal and the impact current signal respectively to realize the tracing of the impact scale factor and the time parameter of the induction coil;

selecting a plurality of current points within the rated current range of the induction coil, acquiring a standard current value corresponding to each current point by using a standard power frequency current transformer under the condition of high power frequency current, acquiring an induction voltage value corresponding to each current point output by the induction coil, determining scale factors of the induction coil under different current points according to the induction voltage value and the standard current value, determining a linearity parameter of the induction coil within the full-scale range according to the scale factors of the induction coil under different current points, and realizing the traceability of the scale factor linearity of the induction coil;

performing a square wave response test on the induction coil by using a current square wave source, acquiring a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured, determining the dynamic characteristic of the induction coil when the impulse current is measured according to the first square wave response characteristic parameter, and tracing the dynamic characteristic of the induction coil;

inputting an impulse voltage signal with a preset amplitude value to the secondary measuring equipment by using an impulse voltage standard wave source, acquiring a second voltage signal output by the secondary measuring equipment, and determining a second impulse scale factor and a second time parameter measurement of the secondary measuring equipment according to the voltage values and time parameters of the second voltage signal and the impulse voltage signal respectively to realize tracing of the impulse scale factor and the time parameter of the secondary measuring equipment;

and performing a square wave response test on the secondary measuring equipment by using a voltage square wave source, acquiring a second square wave response characteristic parameter of the secondary measuring equipment when different preset impulse voltage waveforms are measured, determining the dynamic characteristic of the secondary measuring equipment when the impulse voltage is measured according to the second square wave response characteristic parameter, and tracing the dynamic characteristic of the secondary measuring equipment.

2. The method according to claim 1, wherein the determining the dynamic characteristic of the induction coil when measuring the impulse current according to the first square wave response characteristic parameter realizes tracing the dynamic characteristic of the induction coil, and comprises:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

3. The method according to claim 1, wherein the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each comprise: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

4. The method of claim 1, wherein the rise time of the current square wave source is less than 5ns, the pulse width is greater than 500ns, and the plateau portion dip is less than 2%.

5. The method of claim 1, further comprising:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

6. A magnitude traceability system of an induction coil-based inrush current measurement device, the inrush current measurement device comprising: an induction coil and a secondary measurement device, the system comprising:

the device comprises an impact scale factor tracing unit of an induction coil, a first time parameter measuring unit and a second time parameter measuring unit, wherein the impact scale factor tracing unit is used for inputting an impact current signal with a preset amplitude value to the induction coil by using an impact current standard wave source, acquiring a first voltage signal output by the induction coil, and determining a first impact scale factor and a first time parameter of the induction coil according to the current values and time parameters of the first voltage signal and the impact current signal respectively to realize tracing of the impact scale factor and the time parameter of the induction coil;

the scale factor linearity tracing unit of the induction coil selects a plurality of current points within the rated current range of the induction coil, under the condition of power frequency heavy current, a standard current value corresponding to each current point is obtained by using a standard power frequency current transformer, an induction voltage value corresponding to each current point output by the induction coil is obtained, the scale factors of the induction coil under different current points are determined according to the induction voltage value and the standard current value, and the linearity parameter of the induction coil within the full-scale range is determined according to the scale factors of the induction coil under different current points, so that the tracing of the scale factor linearity of the induction coil is realized;

the dynamic characteristic tracing unit of the induction coil is used for carrying out a square wave response test on the induction coil by utilizing a current square wave source, acquiring a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured, determining the dynamic characteristic of the induction coil when the impulse current is measured according to the first square wave response characteristic parameter, and realizing the tracing of the dynamic characteristic of the induction coil;

the impact scale factor tracing unit of the secondary measurement equipment is used for inputting an impact voltage signal with a preset amplitude value to the secondary measurement equipment by utilizing an impact voltage standard wave source, acquiring a second voltage signal output by the secondary measurement equipment, and determining second impact scale factor and second time parameter measurement of the secondary measurement equipment according to the voltage values and time parameters of the second voltage signal and the impact voltage signal respectively to realize tracing of the impact scale factor and the time parameter of the secondary measurement equipment;

and the dynamic characteristic tracing unit of the secondary measuring equipment is used for performing a square wave response test on the secondary measuring equipment by using a voltage square wave source, acquiring a second square wave response characteristic parameter of the secondary measuring equipment when different preset impulse voltage waveforms are measured, determining the dynamic characteristic of the secondary measuring equipment when the impulse voltage is measured according to the second square wave response characteristic parameter, and realizing the tracing of the dynamic characteristic of the secondary measuring equipment.

7. The system according to claim 6, wherein the dynamic characteristic tracing unit of the induction coil determines the dynamic characteristic of the induction coil when measuring the inrush current according to the first square wave response characteristic parameter, so as to implement tracing of the dynamic characteristic of the induction coil, and includes:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

8. The system according to claim 6, wherein the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each comprise: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

9. The system of claim 6, wherein the rise time of the current square wave source is less than 5ns, the pulse width is greater than 500ns, and the plateau portion dip is less than 2%.

10. The system of claim 6, further comprising:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

Technical Field

The invention relates to the technical field of large current measurement, in particular to a magnitude tracing method and a magnitude tracing system of an impulse current measuring device based on an induction coil.

Background

The impulse current measurement and calibration technology is widely applied to performance tests of lightning protection and on-line monitoring equipment of an electric power system, the measurement accuracy directly influences the lightning protection performance evaluation result of the electric power equipment, and the safe and stable operation of the electric power system is related. The only method for ensuring the measurement accuracy of the impulse current measurement system is value tracing, and an approved measurement device needs to be regularly compared and calibrated with a standard measurement device. Due to the lack of mature impulse current magnitude tracing method and theoretical support, the impulse current measurement standard is not established in China, and magnitude transmission work cannot be effectively carried out. Therefore, there is a need to develop a method for tracing inrush current, a standard device and a calibration technique.

FIG. 1 is a typical indexWaveform diagram of type impulse current, wherein the wave front time is T₁，T₁1.25 XT, half peak time T₂Generally denoted as T₁/T₂Type impulse current waveform, the time parameter of standard lightning impulse current is 8/20 mus. FIG. 2 is a waveform diagram of a rectangular impact current with a duration T_dTotal duration of T_tGenerally denoted as T_d/T_tType rush current, such as 500/700 mus.

Compared with direct current and power frequency current, the measuring level of the measuring system is influenced by the grounding point, the connection mode of the conversion device, the electromagnetic interference of the impact current generator, the influence of ground potential lifting on the measuring instrument, analysis software, the performance of the measuring instrument and the conversion device thereof, environmental conditions and the like. Therefore, the magnitude of the impulse current is extremely difficult to trace, and how to trace the scale factor and the time parameter of the impulse current measuring device to the national standard, accurately separate and extract various influencing factor parameters and reasonably evaluate the parameters is difficult. Therefore, although our country starts to research the impulse current measuring technology from the 80 s of the 20 th century, and continually explores how to improve the performance of the impulse current conversion device and improve the measuring capability and level of the impulse current, the impulse current standard measuring device is not established in the late time. Among the calibration capabilities published by the measurement institute of international countries, only the german PTB laboratory, which has the capability of calibrating the peak value and time parameter of the inrush current, established a standard measurement system for the inrush current of 20kA (8/20 μ s) and has a scale factor measurement uncertainty of 5 × 10^-3(k 2), time parameter measurement uncertainty 2 × 10^-2(k＝2)。

A common measuring device for the impulse current is a current divider and an induction coil. The shunt is directly connected in series into a current loop to be measured, the shunt has the excellent characteristic of quick response, but due to the attachment effect, the amplitude and the pulse width of the measured current are limited, the access of the original current loop is required to be cut off during measurement, and the field application range is limited; the induction coil is used for measuring the impact current based on the magnetic induction theorem, the direct access current loop is not needed during measurement, the installation is more convenient, the measurement range is wider, and the application in the impact current measurement is wider. As shown in fig. 3, the impulse current measuring device based on induction coil is a schematic diagram, which includes a current converting device (induction coil) and a secondary measuring system [ digital recorder (digital oscilloscope + attenuator) ], and the meaning of each parameter is shown in table 1. For the magnitude tracing method of the impulse current, similar to the impulse voltage, the internationally prevailing method is to trace the magnitudes of the scale factor and the time parameter respectively for the current conversion device and the secondary measurement equipment.

TABLE 1 parameter table

IC-induction coil;	s-coil external shielding;
		rk-matching resistance;	MC-measuring cable;
h-shielding the chassis;	m-a measuring instrument;
		f is a filter;	t-isolation transformer

Therefore, the invention provides a magnitude tracing method suitable for an induction coil type impact current measuring device.

Disclosure of Invention

The invention provides a magnitude tracing method and a magnitude tracing system of an impulse current measuring device based on an induction coil, and aims to solve the problem of tracing the magnitude of the impulse current measuring device based on the induction coil.

In order to solve the above problems, according to an aspect of the present invention, there is provided a magnitude tracing method of an induction coil-based inrush current measurement apparatus, the inrush current measurement apparatus including: an induction coil and a secondary measurement device, the method comprising:

inputting an impact current signal with a preset amplitude value to the induction coil by using an impact current standard wave source, acquiring a first voltage signal output by the induction coil, and determining a first impact scale factor and a first time parameter measurement of the induction coil according to the current values and time parameters of the first voltage signal and the impact current signal respectively to realize the tracing of the impact scale factor and the time parameter of the induction coil;

selecting a plurality of current points within the rated current range of the induction coil, acquiring a standard current value corresponding to each current point by using a standard power frequency current transformer under the condition of high power frequency current, acquiring an induction voltage value corresponding to each current point output by the induction coil, determining scale factors of the induction coil under different current points according to the induction voltage value and the standard current value, determining a linearity parameter of the induction coil within the full-scale range according to the scale factors of the induction coil under different current points, and realizing the traceability of the scale factor linearity of the induction coil;

performing a square wave response test on the induction coil by using a current square wave source, acquiring a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured, determining the dynamic characteristic of the induction coil when the impulse current is measured according to the first square wave response characteristic parameter, and tracing the dynamic characteristic of the induction coil;

inputting an impulse voltage signal with a preset amplitude value to the secondary measuring equipment by using an impulse voltage standard wave source, acquiring a second voltage signal output by the secondary measuring equipment, and determining a second impulse scale factor and a second time parameter measurement of the secondary measuring equipment according to the voltage values and time parameters of the second voltage signal and the impulse voltage signal respectively to realize tracing of the impulse scale factor and the time parameter of the secondary measuring equipment;

and performing a square wave response test on the secondary measuring equipment by using a voltage square wave source, acquiring a second square wave response characteristic parameter of the secondary measuring equipment when different preset impulse voltage waveforms are measured, determining the dynamic characteristic of the secondary measuring equipment when the impulse voltage is measured according to the second square wave response characteristic parameter, and tracing the dynamic characteristic of the secondary measuring equipment.

Preferably, the determining the dynamic characteristic of the induction coil when measuring the inrush current according to the first square wave response characteristic parameter to realize tracing of the dynamic characteristic of the induction coil includes:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

Preferably, the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each include: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

Preferably, the rising time of the current square wave source is less than 5ns, the pulse width is more than 500ns, and the degree of flat-top portion reduction is less than 2%.

Preferably, wherein the method further comprises:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

According to another aspect of the present invention, there is provided a magnitude tracing system of an induction coil-based inrush current measurement apparatus, the inrush current measurement apparatus comprising: an induction coil and a secondary measurement device, the system comprising:

the device comprises an impact scale factor tracing unit of an induction coil, a first time parameter measuring unit and a second time parameter measuring unit, wherein the impact scale factor tracing unit is used for inputting an impact current signal with a preset amplitude value to the induction coil by using an impact current standard wave source, acquiring a first voltage signal output by the induction coil, and determining a first impact scale factor and a first time parameter of the induction coil according to the current values and time parameters of the first voltage signal and the impact current signal respectively to realize tracing of the impact scale factor and the time parameter of the induction coil;

the scale factor linearity tracing unit of the induction coil selects a plurality of current points within the rated current range of the induction coil, under the condition of power frequency heavy current, a standard current value corresponding to each current point is obtained by using a standard power frequency current transformer, an induction voltage value corresponding to each current point output by the induction coil is obtained, the scale factors of the induction coil under different current points are determined according to the induction voltage value and the standard current value, and the linearity parameter of the induction coil within the full-scale range is determined according to the scale factors of the induction coil under different current points, so that the tracing of the scale factor linearity of the induction coil is realized;

the dynamic characteristic tracing unit of the induction coil is used for carrying out a square wave response test on the induction coil by utilizing a current square wave source, acquiring a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured, determining the dynamic characteristic of the induction coil when the impulse current is measured according to the first square wave response characteristic parameter, and realizing the tracing of the dynamic characteristic of the induction coil;

the impact scale factor tracing unit of the secondary measurement equipment is used for inputting an impact voltage signal with a preset amplitude value to the secondary measurement equipment by utilizing an impact voltage standard wave source, acquiring a second voltage signal output by the secondary measurement equipment, and determining second impact scale factor and second time parameter measurement of the secondary measurement equipment according to the voltage values and time parameters of the second voltage signal and the impact voltage signal respectively to realize tracing of the impact scale factor and the time parameter of the secondary measurement equipment;

and the dynamic characteristic tracing unit of the secondary measuring equipment is used for performing a square wave response test on the secondary measuring equipment by using a voltage square wave source, acquiring a second square wave response characteristic parameter of the secondary measuring equipment when different preset impulse voltage waveforms are measured, determining the dynamic characteristic of the secondary measuring equipment when the impulse voltage is measured according to the second square wave response characteristic parameter, and realizing the tracing of the dynamic characteristic of the secondary measuring equipment.

Preferably, the tracing unit of dynamic characteristics of the induction coil determines the dynamic characteristics of the induction coil when measuring the inrush current according to the first square wave response characteristic parameter, so as to implement tracing of the dynamic characteristics of the induction coil, and includes:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

Preferably, the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each include: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

Preferably, the rising time of the current square wave source is less than 5ns, the pulse width is more than 500ns, and the degree of flat-top portion reduction is less than 2%.

Preferably, wherein the system further comprises:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

The invention provides a magnitude tracing method and a magnitude tracing system of an impulse current measuring device based on an induction coil, wherein the impulse current measuring device comprises the following components: induction coil and secondary measuring equipment, the scale factor of a whole set of measuring device is the scale factor product of induction coil's scale factor and secondary measuring equipment, consequently separately carries out the traceability of scale factor with induction coil and secondary measuring equipment, and this method makes the traceability have more the operability, and the process of tracing to the source includes: tracing the impact scale factor and the time parameter of the induction coil by using an impact current standard wave source; tracing the scale factor linearity of the induction coil by using a standard power frequency current transformer; tracing the dynamic characteristics of the induction coil by utilizing a current square wave source; tracing the impact scale factor and the time parameter of the secondary measurement equipment by using an impact voltage standard wave source; and tracing the dynamic characteristics of the secondary measurement equipment by using a voltage square wave source. The invention provides a complete technical chain for tracing the magnitude of the impulse current, lays a foundation for establishing an impulse current standard measurement system, and provides a technical method for solving the calibration test of the impulse current measurement device in the power system and industrial production.

Drawings

A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:

FIG. 1 is a waveform diagram of a type index type surge current;

FIG. 2 is a waveform diagram of a rectangular impact current;

FIG. 3 is a schematic diagram of an induction coil based inrush current measurement device;

FIG. 4 is a flow chart of a magnitude tracing method 400 for an induction coil-based inrush current measurement device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an induction coil based inrush current reference measurement apparatus according to an embodiment of the present invention;

FIG. 6 is a magnitude tracing block diagram of an induction coil based inrush current standard measurement apparatus according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of an induction coil square wave response test according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a magnitude tracing system 800 of an induction coil-based inrush current measurement apparatus according to an embodiment of the present invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

Fig. 4 is a flowchart of a magnitude tracing method 400 of an induction coil-based inrush current measurement apparatus according to an embodiment of the present invention. As shown in fig. 4, in the magnitude tracing method of the inrush current measurement apparatus based on the induction coil according to the embodiment of the present invention, the induction coil and the secondary measurement device are separately calibrated, and the method makes the tracing more operable, and the tracing process includes: tracing the impact scale factor and the time parameter of the induction coil by using an impact current standard wave source; tracing the scale factor linearity of the induction coil by using a standard power frequency current transformer; tracing the dynamic characteristics of the induction coil by utilizing a current square wave source; tracing the impact scale factor and the time parameter of the secondary measurement equipment by using an impact voltage standard wave source; and tracing the dynamic characteristics of the secondary measurement equipment by using a voltage square wave source. The invention provides a complete technical chain for tracing the magnitude of the impulse current, lays a foundation for establishing an impulse current standard measurement system, and provides a technical method for solving the calibration test of the impulse current measurement device in the power system and industrial production. In a quantity tracing method 400 of an impulse current measuring device based on an induction coil according to an embodiment of the present invention, starting from step 401, the impulse current measuring device includes: in step 401, an impulse current signal with a preset amplitude is input to the induction coil by using an impulse current standard wave source, a first voltage signal output by the induction coil is obtained, and measurement of a first impulse scale factor and a first time parameter of the induction coil is determined according to current values and time parameters of the first voltage signal and the impulse current signal respectively, so that traceability of the impulse scale factor and the time parameter of the induction coil is realized.

The impulse current measuring device based on the induction coil comprises the induction measuring coil at a primary measuring end and data acquisition equipment at a secondary measuring end, wherein the induction coil is connected in an impulse heavy current generating loop, and when a current loop passes through heavy current, a measuring signal of the current loop is transmitted to secondary side measuring equipment through an optical fiber or a coaxial cable. As shown in fig. 5, the scale factor of the whole set of measuring device is the product of the scale factor of the induction measuring coil and the scale factor of the secondary measuring device, i.e. y (t) ═ N₁·N₂X (t). Thus, in the present invention, two portions of the scale factor are separated for magnitude tracing.

Fig. 6 is a magnitude tracing block diagram of an induction coil-based inrush current standard measurement apparatus according to an embodiment of the present invention. All test equipment used in the tracing process can be traced to national components or direct-current voltage and time parameter standards, and the quantity value of the induction coil measuring device is ensured to be indirectly traced to the national standard through the test equipment for tracing.

In the embodiment of the invention, the tracing of the scale factor of the induction coil is divided into two parts according to the amplitude of the current for tracing. The peak scale factor and the time parameter under the small current can be traced to an impact current standard wave source, a wave form is input to the induction coil by using the standard impact current wave source, the induction coil measures the current signal and outputs a corresponding induction voltage signal, and the ratio of the output induction voltage signal to the input current signal is calculated, namely the scale factor of the induction coil under the small current; and calibrating the scale factor under the power frequency current under the heavy current to obtain the linearity of the impact scale factor of the induction coil under the heavy current, thereby realizing the tracing of the induction coil in the full current range. The time parameter measurement error under the low current can be obtained by calculating the difference value of the waveform parameter of the output induced voltage signal and the waveform parameter of the input current signal.

In the invention, the impulse current scale factor of the induction coil under small current is obtained by calibrating an impulse current standard wave source, the impulse current standard wave source can output a current waveform with accurate peak parameter and time parameter, the output waveform parameter is directly related to the resistance, capacitance and inductance parameter and the loop charging voltage value in a loop formed by the standard wave source, and the impulse current standard wave source can be ensured to output the impulse current standard waveform with accurate peak parameter and time parameter by accurately controlling the loop component parameter and the charging voltage value of the impulse current standard wave source. The parameters of the loop components of the standard wave source used in the test are accurately known, the accurate values of the parameters are obtained by comparing the parameters with the national standard, and the scale factor and time parameter values of the induction coil can be indirectly traced to the national standard of national resistance, capacitance, inductance components and direct-current voltage through the impact current standard wave source.

In step 402, a plurality of current points are selected within the rated current range of the induction coil, a standard current value corresponding to each current point is obtained by using a standard power frequency current transformer under a large power frequency current, an induction voltage value corresponding to each current point output by the induction coil is obtained, the scale factors of the induction coil at different current points are determined according to the induction voltage value and the standard current value, the linearity parameters of the induction coil within the full-scale range are determined according to the scale factors of the induction coil at different current points, and the traceability of the scale factor linearity of the induction coil is realized.

In the embodiment of the invention, in order to obtain the scale factor of the induction coil under different amplitude currents, the linearity test of the induction coil is required under a large current. And selecting a plurality of current points within the rated current range of the induction coil, and calibrating the scale factor of the induction coil under each current point. The standard measuring equipment is a standard power frequency current transformer, the power frequency current value measured by the standard power frequency current transformer is a standard current value, the induction voltage value output when the induction coil is used for measuring the power frequency current is divided by the standard current value, the scale factor linearity of the induction coil within a rated large current range can be obtained, and the measured value of the standard power frequency current transformer can be traced to the national power frequency current proportion standard. And calculating the average value of the scale factors corresponding to each current point and the maximum deviation of the scale factors to obtain the linearity parameters of the induction coil.

In step 403, a square wave response test is performed on the induction coil by using a current square wave source, a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured is obtained, and the dynamic characteristic of the induction coil when the impulse current is measured is determined according to the first square wave response characteristic parameter, so that the tracing of the dynamic characteristic of the induction coil is realized.

Preferably, the determining the dynamic characteristic of the induction coil when measuring the inrush current according to the first square wave response characteristic parameter to realize tracing of the dynamic characteristic of the induction coil includes:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

Because the waveform parameters of the impact current are various, the scale factor of the induction coil can possibly change when the induction coil measures the impact current waveforms with different waveform parameters, and therefore, in order to obtain the change of the scale factor of the induction coil when the induction coil measures the impact current waveforms with different time parameters, the invention adopts a square wave response test to obtain the scale factor change values of the induction coil under different time parameters. The invention inputs the square wave current waveform to the induction coil, obtains the square wave response oscillogram output by the induction coil after the actual measurement, and obtains the peak scale factor and the time parameter error of the induction coil when measuring different preset impulse current waveforms by performing convolution integral on the square wave response oscillogram parameter of the square wave response oscillogram output by the induction coil and the different input waveform parameters of the impulse current waveform to be measured, thereby obtaining the dynamic characteristic of the induction coil when measuring the impulse current. The current square wave source for tracing can be traced to the national DC voltage standard and the national time parameter reference.

In step 404, an impulse voltage signal with a preset amplitude is input to the secondary measurement device by using an impulse voltage standard wave source, a second voltage signal output by the secondary measurement device is obtained, and measurement of a second impulse scale factor and a second time parameter of the secondary measurement device is determined according to the voltage value and the time parameter of the second voltage signal and the impulse voltage signal, so that tracing of the impulse scale factor and the time parameter of the secondary measurement device is realized.

In the embodiment of the invention, the impact scale factor and the time parameter of the secondary measurement equipment can be traced to the impact voltage standard wave source. Inputting a waveform to secondary measurement equipment by using an impulse voltage standard wave source, reading an output value of the secondary measurement equipment, calculating the output value of the secondary measurement equipment and an input value of the standard voltage wave source as peak scale factors of the secondary measurement equipment, and calculating a difference value of a waveform time parameter of an output waveform and a waveform time parameter input by the impulse voltage standard wave source as a time parameter measurement error of the secondary measurement equipment.

The impulse scale factor of secondary measurement equipment matched with the induction coil is traced to an impulse voltage standard wave source, the output voltage waveform parameter of the impulse voltage standard wave source is directly related to the loop resistance, the capacitance and the charging voltage of the impulse voltage standard wave source, the loop parameters of the impulse voltage standard wave source are traced to national resistance, capacitance standard and direct current voltage national standard, and the scale factor of the secondary measurement equipment is indirectly traced to the national resistance, capacitance standard and direct current voltage national standard through the impulse voltage standard wave source. The rising time of the secondary measurement equipment is traced to a voltage square wave source, and the magnitude of the voltage square wave source used in the test is also traced to the national direct-current voltage and time parameter reference.

In step 405, a voltage square wave source is used to perform a square wave response test on the secondary measurement device, so as to obtain a second square wave response characteristic parameter of the secondary measurement device when measuring different preset impulse voltage waveforms, and determine a dynamic characteristic of the secondary measurement device when measuring the impulse voltage according to the second square wave response characteristic parameter, thereby implementing the tracing of the dynamic characteristic of the secondary measurement device.

Preferably, the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each include: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

Preferably, the rising time of the current square wave source is less than 5ns, the pulse width is more than 500ns, and the degree of flat-top portion reduction is less than 2%.

Preferably, wherein the method further comprises:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

In the embodiment of the invention, in order to ensure the effectiveness of the magnitude traceability of the impact current measuring device based on the induction coil, the test device used in the traceability process meets the following requirements:

a) standard current wave source: the current wave source is a current wave source capable of outputting accurate peak parameters, the waveform parameters are (4/10) us and (8/20) us, the uncertainty of peak measurement is less than 0.2%, the uncertainty of time parameters is less than 0.5%, and the magnitude of the current wave source can be traced to national resistance, capacitance standards and direct-current voltage national standards.

b) Standard voltage source: the waveform parameters of the voltage wave source capable of outputting accurate peak value parameters are (4/10) us and (8/20) us, the uncertainty of peak value measurement is less than 0.1 percent, and the uncertainty of time parameters is less than 0.5 percent. The waveform parameters of the standard impulse voltage wave source are standard lightning current waveform parameters, the standard impulse voltage wave source consists of a capacitor, a resistor and an inductor with accurately known parameters, a high-precision direct-current voltage source is used for supplying power, the output parameters of the standard impulse voltage wave source can also be traced to the national standards of direct-current voltage and components, and the voltage peak value can cover the full-scale voltage value of the secondary impulse current measuring instrument.

c) A square wave current source: the device is used for carrying out dynamic characteristics on the impact current measuring device, the rising time of the device is less than 5ns, the pulse width of the device is more than 500ns, and the degree of reduction of a flat-top part is less than 2%.

d) The integral circuit matched with the induction coil has good frequency characteristics, the amplitude-frequency characteristics of the integral circuit are flat within the frequency range covered by the impulse current waveform, in order to avoid the influence on the measurement accuracy of the secondary measurement instrument due to the lifting of a site position and electromagnetic interference during measurement, the power supply of the secondary measurement instrument is provided by a UPS or an isolation power supply, and meanwhile, in order to further ensure the stability of the power supply, a filter is added at the rear end of the isolation power supply, so that the stability and the unicity of the power supply are further ensured.

In the present invention, the influencing factors influencing the measurement accuracy of the inrush current include linearity, short-term stability, long-term stability, dynamic characteristics, influence of the current of the adjacent loop, environmental conditions, and the like. The measurement can be carried out according to the characteristic requirements of the impulse current measuring device, and the uncertainty component introduced by each influence factor is calculated through the test result.

The following specifically exemplifies embodiments of the present invention

The magnitude tracing step flow of the impact current measuring device based on the induction coil is divided into two parts:

1. inductive coil magnitude tracing

1.1 calibration of the Impulse Scale factor of an Induction coil

Calibrating the impact scale factor and time parameter of the induction coil by adopting an impact current standard wave source, enabling the induction coil to pass through an output current conductor loop of the impact current standard wave source, controlling the impact current standard wave source to output a current waveform with a specified current value, and measuring the change of the induction coilThe impulse current value of the voltage signal is obtained, so that an output voltage signal is induced, the voltage signal is input into a digital recorder or a digital oscilloscope through a coaxial cable, and if the waveform parameters of an impulse current standard wave source during calibration are as follows: peak value I_nAnd a time parameter T_1nAnd T_2nRecording the peak current U output by the induction coil₀Wave front time T₁₀And wave tail time value T₂₀And calculating the scale factor and time parameter error of the induction coil by using the parameters, comprising the following steps: 1) the method for calculating the actually measured scale factor of the induction coil comprises the following steps: k₁＝U₀/I_n(ii) a 2) The time parameter measurement error calculation method of the induction coil comprises the following steps: delta T₁＝(T₁₀-T_1n)/T_1n，△T₂＝(T₂₀-T_2n)/T_2n。

1.2 Square wave response test

The square wave current source is adopted to carry out a square wave response test on the induction coil, during the test, the induction coil is connected into a square wave current forming loop in a penetrating mode, and a test schematic diagram is shown in fig. 7. During testing, the square wave current is triggered to form a loop switch, a square wave current waveform with the rise time less than 5ns can be formed in a current loop, the output waveform of the induction coil is input into an oscilloscope through a coaxial cable, a square wave response oscillogram of the induction coil can be directly observed on the oscilloscope, and the square wave response oscillogram is analyzed and calculated, so that the square wave response characteristic parameters of the induction coil can be obtained, and the method comprises the following steps: rise time T_rStabilization time T_nTest response time T_xThe overshoot parameter β. Performing convolution integral with the waveform to be measured (lightning current waveform) of the induction coil according to the waveform of the square wave response, and calculating the input current I measured by the induction coil by using the formula (1) through the convolution integral_inActual output current waveform I at (t)_out(t) comprising:

wherein Iout (t) is output current; i' in (t) is the first derivative of the input current; g (t) is the unit square wave response.

If the waveform expression of the lightning current waveform to be measured is I_in(t)＝A(e^(-at)-e^(-bt)) Then for a given current waveform, the A, a and b values in the current expression are determined. By comparing Io_ut(t) and I_in(t), the dynamic characteristic parameters of the induction coil are obtained, and the uncertainty introduced by the dynamic characteristic can be calculated according to the dynamic characteristic parameters.

1.3 linearity test

And under the condition of large power frequency current, the linearity test is carried out on the induction coil within the rated current range of the induction coil. If the rated current of the induction coil is 100kA, selecting five current points of 20kA, 40kA, 60kA, 80kA and 100kA, adopting a standard industrial frequency current transformer as standard current measuring equipment, calibrating the scale factors of the induction coil under the above 5 current points to obtain the linearity test parameters of the induction coil, and if the above 5 current points are respectively K, the scale factors of the Rogowski coil are respectively K₁、K₂、K₃、K₄、K₅With an average scale factor of K₀＝(K₁+K₂+K₃+K₄+K₅)/5，K₁～K₅The maximum deviation from the mean scale factor is K_xThen K is_xDeviation from the mean (K)_x-K₀)/K₀Is a linearity parameter of the induction coil.

2. Quantity value tracing of secondary measuring equipment

When the induction coil measures the impulse current, a large current signal to be measured is induced into an impulse voltage signal and transmitted to the digital recorder through the coaxial cable. Therefore, for the secondary measurement equipment, the selected standard wave source for tracing is a voltage standard wave source, the waveform parameter of the standard wave source is consistent with the impulse current waveform time parameter, the impulse voltage standard wave source time parameter adopted in the scheme comprises two types of (4/10) mu s and (8/20) mu s, and the peak voltage is 800V.

2.1 calibration of impact Scale factor and time parameter error

The method comprises the steps of adopting a 1000V impulse voltage standard wave source to calibrate scale factors and time parameters of each voltage gear of the digital recorder in a measuring range of the digital recorder, inputting the output end of the impulse voltage standard wave source to the input end of the digital recorder through a coaxial cable which is 1m long and has 50 omega of impedance, and setting the peak value of a waveform parameter to be measured and the waveform time parameter range in the digital recorder matched software.

The rated voltage of the digital recorder is 1000V, in the test, the standard wave source of impulse voltage is adopted to output 200V, 400V, 600V, 800V and 1000V, the standard wave forms of five voltages are adopted, under the positive and negative polarities, each voltage point is repeatedly measured for 10 times, the measured wave forms are recorded, and the average value U of the measured wave form parameters of the digital recorder under each voltage point is calculated_p、T₁、T₂If the actual output voltage value and the time parameter of the impulse voltage standard wave source are U₀、T_1nAnd T_2n。

The method for calculating the actually measured scale factor value of the digital recorder comprises the following steps: k₁＝U₀×K₀/U_p(ii) a The method for calculating the time parameter measurement error of the digital recorder comprises the following steps: delta T₁＝(T_1-T_1n)/T_1n，△T₂＝(T_2-T_2n)/T_2n。

2.2 dynamic characteristics test

And a voltage square wave source is adopted to carry out dynamic test on secondary measurement equipment matched with the induction coil. The voltage square wave source adopts a descending square wave voltage source, the output voltage range of the voltage square wave source is within the rated voltage measurement range of the digital recorder, and the rising time T of the square wave response waveform of the digital recorder is recorded in an important way_rAnd a settling time T_NAnd determining whether the performance parameters of the secondary measurement equipment meet the measurement requirements or not according to the dynamic characteristic test result.

Fig. 8 is a schematic structural diagram of a magnitude tracing system 800 of an induction coil-based inrush current measurement apparatus according to an embodiment of the present invention. As shown in fig. 8, the magnitude traceability system 800 of the impulse current measuring device based on an induction coil according to the embodiment of the present invention includes: an impact scale factor tracing unit 801 of the induction coil, a power frequency scale factor tracing unit 802 of the induction coil, a dynamic characteristic tracing unit 803 of the induction coil, an impact scale factor tracing unit 804 of the secondary measurement device, and a dynamic characteristic tracing unit 805 of the secondary measurement device. The rush current measuring device includes: induction coils and secondary measurement devices.

Preferably, the impact scale factor tracing unit 801 of the induction coil is configured to input an impact current signal with a preset amplitude to the induction coil by using an impact current standard wave source, obtain a first voltage signal output by the induction coil, and determine measurement of the first impact scale factor and the first time parameter of the induction coil according to current values and time parameters of the first voltage signal and the impact current signal, respectively, so as to implement tracing of the impact scale factor and the time parameter of the induction coil.

Preferably, the scale factor linearity tracing unit 802 of the induction coil is configured to select a plurality of current points within a rated current range of the induction coil, obtain a standard current value corresponding to each current point by using a standard power frequency current transformer under a large power frequency current, obtain an induced voltage value corresponding to each current point output by the induction coil, determine the scale factors of the induction coil at different current points according to the induced voltage value and the standard current value, and determine the linearity parameter of the induction coil within a full-scale range according to the scale factors of the induction coil at different current points, thereby implementing the tracing of the scale factor linearity of the induction coil.

Preferably, the dynamic characteristic tracing unit 803 of the induction coil is configured to perform a square wave response test on the induction coil by using a current square wave source, obtain a first square wave response characteristic parameter of the induction coil when different preset impulse current waveforms are measured, determine a dynamic characteristic of the induction coil when the impulse current is measured according to the first square wave response characteristic parameter, and implement tracing of the dynamic characteristic of the induction coil.

Preferably, the tracing unit 803 of the dynamic characteristic of the induction coil determines the dynamic characteristic of the induction coil when measuring the inrush current according to the first square wave response characteristic parameter, so as to implement tracing of the dynamic characteristic of the induction coil, including:

and performing convolution integral on the first square wave response waveform parameter and waveform parameters corresponding to different impulse current waveforms to be detected by using an integral circuit to determine peak value and time parameter measurement of the induction coil when different preset impulse current waveforms are measured, and determining the dynamic characteristic of the induction coil according to the peak value and time parameter measurement to realize the tracing of the dynamic characteristic of the induction coil.

Preferably, the rising time of the current square wave source is less than 5ns, the pulse width is more than 500ns, and the degree of flat-top portion reduction is less than 2%.

Preferably, the impact scale factor tracing unit 804 of the secondary measurement device is configured to input an impact voltage signal with a preset amplitude to the secondary measurement device by using an impact voltage standard wave source, acquire a second voltage signal output by the secondary measurement device, and determine measurement of a second impact scale factor and a second time parameter of the secondary measurement device according to the voltage value and the time parameter of the second voltage signal and the impact voltage signal, respectively, so as to implement tracing of the impact scale factor and the time parameter of the secondary measurement device.

Preferably, the dynamic characteristic tracing unit 805 of the secondary measurement device is configured to perform a square wave response test on the secondary measurement device by using a voltage square wave source, obtain a second square wave response characteristic parameter of the secondary measurement device when measuring different preset impulse voltage waveforms, determine a dynamic characteristic of the secondary measurement device when measuring the impulse voltage according to the second square wave response characteristic parameter, and implement tracing of the dynamic characteristic of the secondary measurement device.

Preferably, the waveform parameters of the output waveforms of the surge current standard wave source and the surge voltage standard wave source each include: (4/10) us and (8/20) us, and the uncertainty of peak measurement is less than 0.2 percent, and the uncertainty of time parameters is less than 0.5 percent; the values of the impulse voltage standard wave source and the impulse current standard wave source can be traced to national resistance, capacitance standard and direct current voltage national standard.

Preferably, wherein the system further comprises:

the power supply for setting the secondary measurement equipment is provided by a UPS power supply or an isolation power supply, and a filter is arranged at the rear end of the isolation power supply.

The system 800 for tracing the magnitude of the impulse current measuring device based on the induction coil according to the embodiment of the present invention corresponds to the method 400 for tracing the magnitude of the impulse current measuring device based on the induction coil according to another embodiment of the present invention, and is not described herein again.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.