CN115902356B - Non-invasive measurement method for high-frequency component of power-on voltage of electric locomotive - Google Patents

Abstract

The invention relates to a non-invasive measurement method for the high-frequency component of the electric locomotive receiving voltage, comprising: estimating the parasitic capacitance value of the electric locomotive according to the structure and corresponding parameters of the downlink cable of the electric locomotive obtained on the spot; Deploy a current sensor that meets the sensitivity requirements on the grounding line; the sensitivity of the current sensor is determined according to the rated power and parasitic capacitance of the electric locomotive; the measurement system is calibrated, and the calibration represents the relationship between the received voltage and the output voltage of the measurement system Transfer function; determine the high-frequency component of the electric locomotive under test based on the measured value of the transfer function and the measurement system; with the help of the core-skin coaxial structure that exists stably in the downlink cable of the pantograph, the grounding of the shielded sheath The current sensor is deployed online to separate the high-amplitude power frequency component from the relatively low-amplitude but high-frequency component, which greatly reduces the interference caused by the background voltage of the traction network to the measurement.

Description

A non-intrusive measurement method for high-frequency components of electric locomotive receiving voltage

Technical Field

The invention relates to the field of electrical signal characteristic quantity measurement, and in particular to a non-intrusive measurement method for high-frequency components of power receiving voltage of an electric locomotive.

Background Art

Electric locomotives are prone to arcing in the bow and catenary due to multiple factors such as ground subsidence and misoperation during operation. Its characteristics need to be detected in time and compensation operations should be performed. Existing electric locomotive bow and catenary arc detection mostly uses "optical equipment" to photograph the bow and catenary, and uses blue light to determine whether there is an arc between the two. The disadvantage of this method is that the purchase and subsequent maintenance costs of blue light equipment are high, and it is difficult to fully deploy it on non-important passenger electric locomotives such as existing freight trains.

In the power system, the measurement of electrical quantities is already very mature, and the equipment is cheap. If the pantograph voltage of the electric locomotive can be obtained through electrical measurement, and then used as the basis for analyzing the arcing of the pantograph network, it can greatly fill the gap in the detection of arcs in existing lines. There are two measurement difficulties in this solution:

First, the voltage on the pantograph side of an electric locomotive is as high as 25KV, but due to the extremely high safety operating specifications of electric locomotives, the conventional contact voltage division measurement solution has a high risk and is difficult to comply with due to contact with the high-voltage side. Therefore, an unconventional solution is required to perform a "non-invasive" measurement of the receiving voltage.

The second is that the measurement system is difficult to calibrate. Unlike conventional experiments where various source signals can be manually configured for calibration, the component experimental process in the traction network cannot be controlled. In addition, the high-amplitude power frequency component (background voltage) and the low-amplitude but high-frequency component in the voltage are mixed together, making it difficult to perform targeted calibration of the measurement system.

Summary of the invention

The present invention aims at the technical problems existing in the prior art and provides a non-intrusive measurement method for the high-frequency component of the power receiving voltage of an electric locomotive, thereby solving the problem of large interference caused by the background voltage of the traction network when measuring the high-frequency component of the power receiving voltage of an electric locomotive.

According to a first aspect of the present invention, there is provided a non-intrusive measurement method for a high-frequency component of a power supply voltage of an electric locomotive, comprising:

Step 1, estimating the parasitic capacitance value C of the electric locomotive according to the structure and corresponding parameters of the electric locomotive downlink cable obtained on site;

根据所述电力机车的额定功率P和寄生电容值C确定；Step 2, constructing a measurement system for measuring the high-frequency component of the power receiving voltage, including: deploying a current sensor that meets the sensitivity requirements on the ground wire of the shielded outer skin; the sensitivity of the current sensor

Determined according to the rated power P and parasitic capacitance value C of the electric locomotive;

；基于所述传变函数

和所述测量系统的测量值确定被测电力机车的受电电压高频分量。Step 3: calibrate the measurement system to calibrate the transfer function representing the relationship between the receiving voltage and the output voltage of the measurement system.

Based on the transfer function

The high frequency component of the power receiving voltage of the measured electric locomotive is determined by the measured value of the measuring system.

On the basis of the above technical solution, the present invention can also make the following improvements.

的确定方法为：Optionally, the sensitivity of the current sensor

The method for determining is:

；

;

表示所述电力机车的受电暂态电压高频分量对应的最大频率。in,

Indicates the maximum frequency corresponding to the high-frequency component of the transient voltage received by the electric locomotive.

的过程包括：Optionally, in step 3, the transfer function of the measurement system is determined

The process includes:

Step 301, installing a voltage standard that meets the frequency range requirements and sensitivity requirements, wherein the voltage standard is connected between the pantograph end of the electric locomotive and the ground;

。Step 302: synchronously sample to obtain a set of waveform data of the voltage output by the voltage standard device and the measurement system, compare at least two sets of the waveform data, and calculate the transfer function

.

，上限截止频率不低于

，灵敏度为

。Optionally, the lower cut-off frequency of the voltage standard is not higher than

, the upper cut-off frequency is not less than

, the sensitivity is

.

Optionally, step 302 includes:

、所述测量系统的输出幅值数据序列

以及基于所述波形数据的采样率和采样次数构成的频率数据序列f；Step 30201, perform a windowed Fourier transform on the two sets of waveform data to obtain the output amplitude data sequence of the voltage standard device.

, the output amplitude data sequence of the measurement system

and a frequency data sequence f formed based on the sampling rate and sampling times of the waveform data;

中抽取数据构成数据数列

，在所述数据序列

中抽取对应的数据，将该对应的数据除以所述频率数据序列f中对应的值后构建得到数据数列

；Step 30302, from the data sequence

Extract data from the data to form a data series

, in the data sequence

The corresponding data is extracted from the frequency data sequence f, and the corresponding data is divided by the corresponding value in the frequency data sequence f to construct a data sequence

;

和数据数列

之间的大小关系的拟合目标模型，拟合求解得到所述拟合目标模型的系数后，确定所述测量系统的传变函数为该系数对应的拟合目标模型。Step 30303, set the data sequence

and data series

A fitting target model of the size relationship between them is obtained, and after fitting and solving the coefficients of the fitting target model, the transfer function of the measurement system is determined to be the fitting target model corresponding to the coefficients.

；Optionally, the frequency data sequence

;

，

和N分别为所述波形数据的采样率和采样次数。in,

,

and N are the sampling rate and number of sampling times of the waveform data respectively.

的过程包括：Optionally, the data extracted in step 30301 constitutes a data sequence

The process includes:

个十倍频程子频带；Select a frequency band range and divide the frequency band range into

decade sub-bands;

中抽取对应元素，并选择其中较大的

个，构成包含m×n个元素的数据数列

。In each sub-band, the data sequence

Extract the corresponding elements and select the larger one

, forming a data sequence containing m×n elements

.

，y表示数据数列

中的数据，x表示数据数列

中的数据，

和

为待确定系数。Optionally, the fitting target model is

, y represents the data series

The data in, x represents the data series

The data in

and

is the coefficient to be determined.

The present invention provides a non-invasive measurement method for the high-frequency component of the power receiving voltage of an electric locomotive. With the help of the core-skin structure unique to the incoming line of the electric locomotive, the bow-side voltage is inverted by measuring the current in the shielding layer of the incoming line. Thanks to the characteristic that the high-frequency component has a much higher penetration ability in parasitic capacitance than the power frequency component, the high-frequency component can still be highlighted even under the background interference of high-amplitude power frequency. In view of the dilemma that electric locomotives have extremely high operating requirements and are difficult to calibrate in real time, the present invention provides a calibration method for the measurement system with the help of the consistency of the transfer function of the Rogowski coil in the medium and high frequency bands. Finally, with the help of in-depot experiments and the intermediate frequency components unique to the traction network, the calibration of the measurement system is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a non-intrusive measurement method of a high-frequency component of a power supply voltage of an electric locomotive provided by the present invention;

FIG2 is a cross-sectional view of an electric locomotive incoming line coaxial cable provided by an embodiment of the present invention;

FIG3 is an equivalent circuit diagram of a switchable, self-integrating Rogowski coil provided by an embodiment of the present invention;

FIG4 is a schematic diagram of a calibration principle of a measurement system provided in an embodiment of the present invention;

至

中特有分量的时、频域展示的示意图；FIG. 5 is a diagram of an electric locomotive traction network provided by an embodiment of the present invention.

to

Schematic diagram showing the time and frequency domains of the unique components in the

FIG6 is a flow chart of a method for screening spectral lines in a characteristic frequency domain provided by an embodiment of the present invention.

DETAILED DESCRIPTION

The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

FIG1 is a flow chart of a non-intrusive measurement method for a high-frequency component of a power supply voltage of an electric locomotive provided by the present invention. As shown in FIG1 , the non-intrusive measurement method includes:

Step 1: Estimate the parasitic capacitance value C of the electric locomotive according to the structure and corresponding parameters of the electric locomotive downlink cable obtained on site.

In a specific implementation, the parasitic capacitance value C can be estimated by the structure and corresponding parameters of the electric locomotive downlink cable and the surrounding environment obtained on site.

根据电力机车的额定功率P和寄生电容值C确定。Step 2, constructing a measurement system for measuring the high-frequency component of the receiving voltage, including: deploying a current sensor that meets the sensitivity requirements on the ground wire of the shielded outer skin; the sensitivity of the current sensor

Determined according to the rated power P and parasitic capacitance value C of the electric locomotive.

In a specific implementation, the current sensor can be measured by a non-invasive current probe, and the measurement system can also include an analog-to-digital conversion group and a host computer cascaded with the current sensor to obtain the measurement data of the current sensor in real time.

；基于传变函数

和测量系统的测量值确定被测电力机车的受电电压高频分量。Step 3: calibrate the measurement system and calibrate the transfer function that represents the relationship between the receiving voltage and the output voltage of the measurement system.

; Based on the transfer function

The high-frequency component of the power receiving voltage of the electric locomotive under test is determined by the measured values of the measurement system.

The present invention provides a non-invasive measurement method for the high-frequency component of the power receiving voltage of an electric locomotive. With the help of the core-skin coaxial structure that is stably present in the pantograph downlink cable, a current sensor is deployed on the ground wire of the shielded outer skin, so as to separate the high-amplitude power frequency component and the relatively low-amplitude but high-frequency component, and then convert the measurement of the high-frequency voltage component into the measurement of the current, which greatly reduces the interference of the background voltage of the traction network on the measurement and makes the measurement object stand out.

Example 1

Embodiment 1 provided by the present invention is an embodiment of a non-invasive measurement method for the high-frequency component of the power supply voltage of an electric locomotive provided by the present invention. In this embodiment, the conversion of U-I is realized by the inherent structure of the electric locomotive, and then the measurement and detection of the high-frequency voltage component is realized by non-invasive current measurement. In addition, the method reasonably designs the calibration method in the station, effectively avoiding the problems of large background voltage and difficulty in calibration during the measurement process. In conjunction with Figure 1, it can be seen that the embodiment of the non-invasive measurement method includes:

Step 1: Estimate the parasitic capacitance value C of the electric locomotive according to the structure and corresponding parameters of the electric locomotive downlink cable obtained on site.

根据电力机车的额定功率P和寄生电容值C确定。Step 2, constructing a measurement system for measuring the high-frequency component of the receiving voltage, including: deploying a current sensor that meets the sensitivity requirements on the ground wire of the shielded outer skin; the sensitivity of the current sensor

Determined according to the rated power P and parasitic capacitance value C of the electric locomotive.

的确定方法为：In one possible embodiment, the sensitivity of the current sensor is

The method for determining is:

表示电力机车的受电暂态电压高频分量对应的最大频率。具体的，

可以为该最大频率的±1%偏差截止频率，且频响范围可覆盖弓-网拉弧过程中暂态电压中的全部高频成分。in,

Indicates the maximum frequency corresponding to the high-frequency component of the transient voltage of the electric locomotive. Specifically,

The cut-off frequency can be ±1% deviation of the maximum frequency, and the frequency response range can cover all high-frequency components in the transient voltage during the bow-net arcing process.

；基于传变函数

和测量系统的测量值确定被测电力机车的受电电压高频分量。Step 3: calibrate the measurement system and calibrate the transfer function that represents the relationship between the receiving voltage and the output voltage of the measurement system.

; Based on the transfer function

The high-frequency component of the power receiving voltage of the electric locomotive under test is determined by the measured values of the measurement system.

的过程包括：In a possible embodiment, in step 3, the transfer function of the measurement system is determined

The process includes:

Step 301, installing a voltage standard that meets the frequency range requirements and sensitivity requirements, and the voltage standard is connected between the pantograph end of the electric locomotive and the ground.

，上限截止频率（±0.2%偏差）不低于

，灵敏度为

。In a possible implementation manner, the voltage standard needs to meet the frequency range requirements and sensitivity requirements, and the lower cutoff frequency (±0.2% deviation) of the voltage standard is not higher than

, the upper cut-off frequency (±0.2% deviation) is not less than

, the sensitivity is

.

表示电力机车的受电暂态电压高频分量对应的最大频率，

表示电力机车的受电暂态电压高频分量对应的最小频率。in,

Indicates the maximum frequency corresponding to the high-frequency component of the transient voltage of the electric locomotive.

Indicates the minimum frequency corresponding to the high-frequency component of the transient voltage received by the electric locomotive.

。Step 302: synchronously sample and obtain a set of waveform data of the voltage output by the voltage standard and the measurement system, compare at least two sets of waveform data, and calculate the transfer function

.

≥1MSa/s采样深度不低于16 bit，两组波形的数据量均为

，且不小于20000。In the specific implementation, the voltage standard performs the operation of the pantograph rising connection (or falling cut-out), and uses the acquisition card and the host computer to synchronously record the waveform data of the output voltage of the voltage standard and the measurement system during the sampling process. The sampling rate

≥1MSa/s Sampling depth is not less than 16 bits, and the data volume of the two sets of waveforms is

, and not less than 20000.

In a possible embodiment, step 302 includes:

、测量系统的输出幅值数据序列

以及基于波形数据的采样率和采样次数构成的频率数据序列f。Step 30201, perform a windowed Fourier transform on the two sets of waveform data to obtain the output amplitude data sequence of the voltage standard device.

, the output amplitude data sequence of the measurement system

And a frequency data sequence f composed of the sampling rate and number of sampling times of the waveform data.

。

.

中抽取数据构成数据数列

，在数据序列

序列中抽取对应的数据，将该对应的数据除以频率数据序列f中对应的值后构建得到数据数列

。Step 30302, from the data sequence

Extract data from the data to form a data series

, in the data series

Extract the corresponding data from the sequence, divide the corresponding data by the corresponding value in the frequency data sequence f, and then construct the data series

.

In a possible implementation manner, the process of extracting data in step 30301 includes:

划分为

个十倍频程子频带。Select the frequency band range.

Divide into

decade sub-bands.

中抽取对应元素，并选择其中较大的

个，构成包含m×n个元素的数据数列

。In each sub-band, from the data sequence

Extract the corresponding elements and select the larger one

, forming a data sequence containing m×n elements

.

和数据数列

用于灵敏度估算，具体的，编号可以分别为

、

、

……，具体为：The data series

and data series

Used for sensitivity estimation, specifically, the numbers can be

,

,

..., specifically:

。

.

和数据数列

之间的大小关系的拟合目标模型，拟合求解得到拟合目标模型的系数后，确定测量系统的传变函数为该系数对应的拟合目标模型。Step 30303, set the data sequence

and data series

A fitting target model of the size relationship between them is obtained by fitting and solving the coefficients of the fitting target model, and then the transfer function of the measurement system is determined to be the fitting target model corresponding to the coefficient.

，y表示数据数列

中的数据，x表示数据数列

中的数据，

和

为待确定系数。In a possible embodiment, the fitting target model is

, y represents the data series

The data in, x represents the data series

The data in

and

is the coefficient to be determined.

和数据序列

为参数

、

的观测集，可拟合求解两个未知系数

和

的值分别为

和

，进而获取测量系统的传变函数。In the specific implementation, the data sequence

and data series

For parameters

,

The observation set can be fitted to solve the two unknown coefficients

and

The values are

and

, and then obtain the transfer function of the measurement system.

对应的成分为例，受电电压

与测量系统输出

之间的关系可以为：By frequency

For example, the corresponding component is the receiving voltage

With the measurement system output

The relationship between them can be:

。

.

Example 2

Embodiment 2 provided by the present invention is a specific application embodiment of a non-invasive measurement method for high-frequency components of the power receiving voltage of an electric locomotive provided by the present invention. In conjunction with FIG1 , it can be seen that the specific application embodiment of the non-invasive measurement method includes:

Step 1: Estimate the parasitic capacitance value C of the electric locomotive according to the structure and corresponding parameters of the electric locomotive downlink cable obtained on site.

In this embodiment, a certain HXDXX electric locomotive in Central China is taken as an example. Through preliminary measurements on board, it can be known that the incoming cable part of this model can be divided into 3 sections (including arc bends). Table 1 shows the value table of various parameters of each part of the incoming cable obtained by measurement:

Table 1 Parameter values of each part of the incoming cable

表示第q区段电缆的权重系数，

表示第q区段电缆的等效长度，第2区段为电缆弯折部分。Among them, q=1, 2 or 3 represents the number of each section.

represents the weight coefficient of the cable in the qth section,

It represents the equivalent length of the qth section of the cable, and the second section is the bending part of the cable.

=6.45mm.屏蔽层距离轴心半径

=16.75mm。绝缘材料的相对介电常数

。综合以上数据，可预计算出杂散电容估计值。By looking up the cable model of the electric locomotive, we can know that the internal structure of the cable is shown in Figure 2. Specific parameters: Copper conductor radius

=6.45mm. Shielding layer distance to the axis radius

=16.75mm. Relative dielectric constant of insulating material

Combining the above data, the estimated value of stray capacitance can be pre-calculated.

。

.

表示自由空间介电常数，取值为

。

represents the free space dielectric constant, which is

.

根据所述电力机车的额定功率P和寄生电容值C确定。Step 2, constructing a measurement system for measuring the high-frequency component of the power receiving voltage, including: deploying a current sensor that meets the sensitivity requirements on the ground wire of the shielded outer skin; the sensitivity of the current sensor

It is determined according to the rated power P and the parasitic capacitance value C of the electric locomotive.

。而暂态电压分量所对应的频率可至

=200MHz。因此，完成测量所需的增益为：According to the relevant information and literature on electric locomotives, the rated power of this type of electric locomotive is

The frequency corresponding to the transient voltage component can be

= 200MHz. Therefore, the gain required to complete the measurement is:

。其等效电路模型如附图2所示。根据罗氏线圈设计原理，可按照如下参数设计出符合增益的电流传感器：In view of the fact that the current sensor in the embodiment of the present invention is "non-invasive", the probe should be designed as an openable Rogowski coil. Since the current entering the shielding layer is characterized by high frequency and small amplitude, the gain of the probe and the frequency band it covers are the key design targets. Based on this consideration, the magnetic core is designed to be a "nanocrystalline" material with high magnetic permeability, and its relative magnetic permeability is

The equivalent circuit model is shown in Figure 2. According to the design principle of Rogowski coil, a current sensor that meets the gain can be designed according to the following parameters:

①The number of coil turns is 16.

的结构。② The height of two layers of nanocrystals is

structure.

负载阻抗。③Terminal parallel connection

Load impedance.

=56mm;外半径

=74mm。④Inner radius of the Rogowski coil winding

=56mm;Outer radius

=74mm.

=3.1631 V/A。The actual value of the gain calculated based on the above parameters is approximately

=3.1631 V/A.

In a specific implementation, the difference between the actual gain value and the designed gain value can be corrected by a digital processing part.

FIG4 is a calibration principle diagram of a measurement system provided by an embodiment of the present invention. In conjunction with FIG4, it can be seen that the current sensor is deployed on the ground wire of the shielded outer skin, and there is an equivalent shielding layer stray capacitance between the current sensor and the pantograph end of the electric locomotive. The voltage standard is directly connected between the pantograph end of the electric locomotive and the ground.

、

，其长度均为

。After the equipment is installed, the signal output of the probe and the standard is extended to the synchronous acquisition system controlled by the NI 8841. In this measurement system based on the NI platform, the measurement system signal waveform and the voltage standard waveform obtained by the acquisition card are recorded as

,

, whose lengths are

.

；基于所述传变函数

和所述测量系统的测量值确定被测电力机车的受电电压高频分量。Step 3: calibrate the measurement system to calibrate the transfer function representing the relationship between the receiving voltage and the output voltage of the measurement system.

Based on the transfer function

The high frequency component of the power receiving voltage of the measured electric locomotive is determined by the measured value of the measuring system.

First, perform a windowed Fourier transform on the waveforms of the measurement system and the standard to obtain their frequency domain information:

、

分别为测量系统、标准器信号，其长度为N。k为频率索引，

。

为加窗过程所采用的窗函数，此处以Hann窗为例，有：in,

,

are the measurement system and standard instrument signals respectively, and their length is N. k is the frequency index,

.

The window function used in the windowing process, taking the Hann window as an example, is:

。

.

After windowing and Fourier transform, the frequency domain information can be properly processed to obtain a spectrum with physical meaning:

。

.

至

频段内存在异常分量，如图5所示。故标定过程中，以该分量作为观测对象，通过如图6所示的流程图整理出“灵敏度估算数据数列”，其结果如表2中灵敏度估算数据数列所示。Through actual investigation, it is known that when the pantograph of the electric locomotive contacts the traction network,

to

There are abnormal components in the frequency band, as shown in Figure 5. Therefore, during the calibration process, this component is used as the observation object, and the "sensitivity estimation data series" is sorted out through the flow chart shown in Figure 6. The results are shown in the sensitivity estimation data series in Table 2.

Table 2 Sensitivity estimation data series

的全部数值进行整合，即可得到

数列；将

与

一一对应作商，结果进行整合即为

数列。基于此，可构造拟合目标函数

。以

作为函数中的

；以

作为函数中的

，将数据带入该函数中进行拟合，可求解出：In Table 2,

By integrating all the values of

sequence;

and

Correspond to the quotients one by one, and integrate the results to get

Based on this, the fitting objective function can be constructed

.by

As a function

;by

As a function

, bring the data into the function for fitting, and we can solve:

。

.

Finally, the calibration of the entire measurement system can be completed based on the actual load:

为系统测得信号在f Hz处的幅值，f为所观测量的频率，

为fHz处的反演结果。将中间过程的系数进行封装，即可得到频率f Hz处的传变函数

。in,

is the amplitude of the signal measured by the system at f Hz, where f is the frequency of the observed quantity,

is the inversion result at fHz. By encapsulating the coefficients of the intermediate process, we can get the transfer function at frequency f Hz

.

The pantograph of an electric locomotive and the traction network may cause arcing due to many factors such as misoperation and aging of the pantograph. If it is not identified, it may easily become a hidden danger of burning the network. Real-time measurement of the high-frequency signal characteristics caused by the arc can effectively prevent the hazard from worsening. Regarding the high-frequency component of voltage, an embodiment of the present invention provides a non-invasive measurement method for the high-frequency component of the power receiving voltage of an electric locomotive. By means of the core-skin structure unique to the incoming line of the electric locomotive, the current in the incoming line shielding layer is measured to invert the bow side voltage. Thanks to the characteristic that the high-frequency component has a much higher penetration ability in parasitic capacitance than the power frequency component, the high-frequency component can still be highlighted even under the background interference of high-amplitude power frequency. In view of the dilemma that electric locomotives have extremely high operating requirements and are difficult to calibrate in real time, the present invention uses the consistency of the transfer function of the Rogowski coil in the middle and high frequency bands to provide a calibration method for the measurement system. Finally, with the help of in-depot experiments and the unique intermediate frequency components of the traction network, the calibration of the measurement system is achieved.

Through the in-library experiment, the measurement system to be calibrated and the standard instrument observe the same component, that is, the mid-frequency component unique to the traction network between 1kHz and 10kHz. In this frequency band, the standard instrument can calibrate the probe of the measurement system, and then, with the help of the characteristic of the Rogowski coil probe that "the transfer function has consistency" at mid- and high-frequency, the calibration results completed in the mid-frequency part are extended to the high-frequency band where the arc is located.

In particular, the method described in this patent is different from the existing non-intrusive technology patents in the field of electric locomotives. It is a real-time, quantitative measurement of the high-frequency components of electrical signals, and its application is not limited to fault diagnosis. It is also a real-time measurement on the vehicle, not limited to between two phase segments.

In summary, this method cleverly uses the coaxial structure of the electric locomotive incoming cable to extract the arc characteristic component from the large background voltage, and calibrates the measurement system through reasonable in-depot experiments, which complies with the operating specifications of the electric locomotive and makes the whole solution practical.

It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

The present invention is described with reference to the flowchart and/or block diagram of the method, device (system), and computer program product according to the embodiment of the present invention. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the processes and/or boxes in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one process or multiple processes in the flowchart and/or one box or multiple boxes in the block diagram.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (6)

1. A non-intrusive measurement method for high-frequency components of power supply voltage of an electric locomotive, characterized in that the non-intrusive measurement method comprises: Step 1, estimating the parasitic capacitance value C of the electric locomotive according to the structure and corresponding parameters of the electric locomotive downlink cable obtained on site; Step 2, constructing a measurement system for measuring the high-frequency component of the power receiving voltage, including: deploying a current sensor that meets the sensitivity requirements on the ground wire of the shielded outer skin; the sensitivity of the current sensor

Determined according to the rated power P and parasitic capacitance value C of the electric locomotive; Step 3: calibrate the measurement system to calibrate the transfer function representing the relationship between the receiving voltage and the output voltage of the measurement system.

Based on the transfer function

Determine the high frequency component of the power receiving voltage of the electric locomotive under test by using the measured value of the measuring system; The sensitivity of the current sensor

The method for determining is:

; in,

Indicates the maximum frequency corresponding to the high-frequency component of the transient voltage of the electric locomotive; In step 3, the transfer function of the measurement system is determined

The process includes: Step 301, installing a voltage standard that meets the frequency range requirements and sensitivity requirements, wherein the voltage standard is connected between the pantograph end of the electric locomotive and the ground; Step 302: synchronously sample to obtain a set of waveform data of the voltage output by the voltage standard device and the measurement system, compare at least two sets of the waveform data, and calculate the transfer function

. 2. The non-invasive measurement method according to claim 1, characterized in that the lower cut-off frequency of the voltage standard is not higher than

, the upper cut-off frequency is not less than

, the sensitivity is

. 3. The non-invasive measurement method according to claim 1, wherein step 302 comprises: Step 30201, perform a windowed Fourier transform on the two sets of waveform data to obtain the output amplitude data sequence of the voltage standard device.

, the output amplitude data sequence of the measurement system

and a frequency data sequence f formed based on the sampling rate and sampling times of the waveform data; Step 30302, from the data sequence

Extract data from the data to form a data series

, in the data sequence

The corresponding data is extracted from the frequency data sequence f, and the corresponding data is divided by the corresponding value in the frequency data sequence f to construct a data sequence

; Step 30303, set the data sequence

and data series

A fitting target model of the size relationship between them is obtained, and after fitting and solving the coefficients of the fitting target model, the transfer function of the measurement system is determined to be the fitting target model corresponding to the coefficients. 4. The non-intrusive measurement method according to claim 3, characterized in that the frequency data sequence

; in,

,

and N are the sampling rate and number of sampling times of the waveform data respectively. 5. The non-invasive measurement method according to claim 3, characterized in that the data extracted in step 30301 constitutes a data sequence

The process includes: Select a frequency band range and divide the frequency band range into

decade sub-bands; In each sub-band, the data sequence

Extract the corresponding elements and select the larger one

, forming a data sequence containing m×n elements

. 6. The non-invasive measurement method according to claim 3, characterized in that the fitting target model is

, y represents the data series

The data in, x represents the data series

The data in

and

is the coefficient to be determined.

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