Coal mine power supply fault diagnosis method and system based on pulse signals

Abstract

The invention relates to the technical field of signal fault detection, in particular to a coal mine power supply fault diagnosis method and system based on pulse signals, and the method comprises the steps: obtaining a main line pulse signal of a coal mine power supply line and a branch pulse signal of each branch in a disconnected state; screening out a signal fluctuation time period corresponding to each branch according to the time difference and the signal value difference between the branch pulse signal of each branch and the main line pulse signal; according to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained by combining the difference between the actual time and the theoretical time of the disconnection operation of each branch; and obtaining a fault diagnosis result of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period. According to the invention, a real line pulse fluctuation condition can be obtained, and the accuracy of a fault diagnosis result is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of signal fault detection, and in particular to a pulse signal-based coal mine power supply fault diagnosis method and system. Background Art

[0002] The coal mine power supply system is the core energy guarantee for underground production in coal mines. Its power supply cables are in a working environment with high humidity, high temperature, high probability of mechanical damage, and complex vibration for a long time. Due to line aging and external force damage, there are many short circuit and disconnection faults. Traditional fault detection methods rely on manual inspections and offline tests, and have problems such as low positioning accuracy and delayed response, which are difficult to meet the stringent requirements of modern mines for power supply reliability. Active diagnosis technology based on this pulse signal has become the mainstream of current power supply system fault diagnosis.

[0003] When diagnosing power supply faults in coal mines, the instantaneous voltage changes caused by the opening and closing of equipment on the power supply branch will affect the voltage changes of the line, causing the waveform of the pulse signal to produce uneven signal fluctuations, resulting in low accuracy of the fault diagnosis results for coal mine power supply based on the fluctuations of the pulse signal. Summary of the invention

[0004] In order to solve the technical problem that when the existing method performs fault diagnosis based on pulse signals, the voltage change at the moment of branch opening and closing causes the fault diagnosis result to be less accurate, the purpose of the present invention is to provide a coal mine power supply fault diagnosis method and system based on pulse signals, and the technical scheme adopted is as follows: In a first aspect, the present invention provides a method for diagnosing coal mine power supply faults based on pulse signals, comprising: Obtain the main line pulse signal of the coal mine power supply line and the branch pulse signal of each branch in the disconnected state; According to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal, the signal fluctuation time period corresponding to the disconnection state of each branch is screened out; According to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and theoretical time of the disconnection operation of each branch, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained; According to the pulse fluctuation instability of each branch in each signal fluctuation time period, the fault diagnosis results of the coal mine power supply line are analyzed and obtained.

[0005] Preferably, the method of screening out the signal fluctuation time period corresponding to the disconnection state of each branch according to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal specifically includes: For any branch, the theoretical pulse time length of the branch is determined based on the distance between the branch and the main line pulse generator and the pulse signal transmission speed; Determine the surge time period in the branch disconnection state based on the branch disconnection time node and the theoretical pulse time length; According to the time difference between the time period in which the signal value difference between the branch pulse signal corresponding to the branch and the main line pulse signal is located and the surge time period, the signal fluctuation time period corresponding to the branch disconnection state is obtained.

[0006] Preferably, obtaining the signal fluctuation time period corresponding to the branch disconnection state according to the time difference between the signal value difference between the branch pulse signal corresponding to the branch and the main line pulse signal and the surge time period specifically includes: For any branch, based on the difference in signal values ​​at the same time between the main line pulse signal and the branch pulse signal corresponding to the branch disconnection, determine the pulse difference signal corresponding to each moment of the branch pulse signal; Outside the surge time period, a continuous time period in which the value of the pulse difference signal at each moment meets the threshold requirement is obtained as a signal fluctuation time period corresponding to the branch disconnection state.

[0007] Preferably, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained according to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and the theoretical time of the disconnection operation of each branch, and specifically includes: According to the difference between the theoretical pulse time length corresponding to each branch and the actual duration length of each branch disconnection operation, the position attribution degree of each branch disconnection state is obtained; According to the difference of adjacent signal values ​​of the branch pulse signal corresponding to each branch in each signal fluctuation time period, combined with the position attribution degree, the disconnection pulse attenuation degree of each branch in each signal fluctuation time period is obtained; According to the disconnection pulse attenuation of each branch in each signal fluctuation time period and the signal value fluctuation degree of the branch pulse signal in each signal fluctuation time period, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained.

[0008] Preferably, the position attribution of each branch disconnection state is obtained according to the difference between the theoretical pulse time length corresponding to each branch and the actual duration length of each branch disconnection operation, specifically including: For any branch, the pulse difference signal corresponding to each moment of the branch pulse signal is fitted to obtain the difference signal curve of the branch, the first signal mutation point of the difference signal curve is obtained, and the time length between the branch disconnection time node and the signal mutation point is taken as the actual pulse time length of the branch disconnection; Based on the negative correlation coefficient of the difference between the theoretical pulse time length and the actual pulse time length corresponding to the branch, the position attribution of the branch disconnection state is determined.

[0009] Preferably, the attenuation of the disconnection pulse of each branch in each signal fluctuation time period is obtained according to the difference of adjacent signal values ​​of the branch pulse signal corresponding to each branch in each signal fluctuation time period in combination with the position attribution degree, specifically including: For any branch, based on the inverse of the length of time of the branch in each signal fluctuation time period and the position attribution degree, determine the first characteristic coefficient of each signal fluctuation time period; The accumulated sum of the differences in the signal values ​​of the branch pulse signals at every two adjacent moments in each signal fluctuation time period is used as the second characteristic coefficient of each signal fluctuation time period; The disconnection pulse attenuation degree in each signal fluctuation time period is obtained according to the first characteristic coefficient and the second characteristic coefficient, and the disconnection pulse attenuation degree is a normalized value.

[0010] Preferably, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained according to the disconnection pulse attenuation of each branch in each signal fluctuation time period and the signal value fluctuation degree of the branch pulse signal in each signal fluctuation time period, specifically including: For any branch, the product of the negative correlation coefficient of the disconnection pulse attenuation in each signal fluctuation time period and the signal value variance of all branch pulse signals in the same signal fluctuation time period is normalized to obtain the pulse fluctuation instability in each signal fluctuation time period.

[0011] Preferably, the analysis and obtaining of the fault diagnosis result of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period specifically includes: When the pulse fluctuation instability of each signal fluctuation time period of each branch is less than the preset abnormal threshold, the coal mine power supply line has not failed; When the pulse fluctuation instability of each signal fluctuation time period of each branch is greater than or equal to a preset abnormal threshold, a coal mine power supply line fails.

[0012] Preferably, when a coal mine power supply line fails, the method further comprises: For any signal fluctuation time period where a fault occurs, the signal propagation length is determined based on the product of the propagation speed of the pulse signal and the time length of the signal fluctuation time period, and the location of the fault point is determined using half of the signal propagation length.

[0013] In a second aspect, the present invention provides a coal mine power supply fault diagnosis system based on pulse signals, the system is used to implement the steps of a coal mine power supply fault diagnosis method based on pulse signals, and the coal mine power supply fault diagnosis system based on pulse signals specifically includes: A data acquisition module, used to acquire the main line pulse signal of the coal mine power supply line and the branch pulse signal of each branch in the disconnected state; A data preprocessing module, used to screen out the signal fluctuation time period corresponding to the disconnection state of each branch according to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal; The instability analysis module is used to obtain the pulse fluctuation instability of each branch in each signal fluctuation time period according to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and theoretical time of the disconnection operation of each branch; The fault diagnosis module is used to analyze and obtain the fault diagnosis results of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period.

[0014] The embodiments of the present invention have at least the following beneficial effects: The present invention first obtains the complete main line pulse signal and the branch pulse signal in the state of disconnecting different branches, and provides a data basis for the subsequent process of analyzing the impact of the surge phenomenon caused by the branch disconnection. Then, the difference in the pulse signal value and the time difference between the branch disconnection and the complete main line are analyzed to preliminarily eliminate the influence of the surge phenomenon and screen out the signal fluctuation time period where there may be faults or abnormalities. Further, the fluctuation degree of the signal value in each signal fluctuation time period when the branch is disconnected is analyzed to reflect the degree of fault characteristics shown by the signal fluctuation of the branch disconnection, and the actual and theoretical time difference of the branch disconnection operation is analyzed to reflect the degree of surge characteristics shown by the signal fluctuation of the branch disconnection. The signal instability in the signal fluctuation time period in the state of branch disconnection is quantified by combining these two aspects, and the possibility of the existence of faults in the corresponding time period is characterized. Finally, the diagnosis result of whether a fault occurs is obtained by using the instability of the pulse fluctuation, which can eliminate the interference of the voltage surge caused by the voltage change of the branch, obtain the real pulse signal fluctuation on the line, and then better perform the fault diagnosis of coal mine power supply, and improve the accuracy of fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a flow chart of the steps of a pulse signal-based coal mine power supply fault diagnosis method provided by the present invention; Figure 2 is a flowchart of the steps of the method for obtaining the signal fluctuation time period provided by the present invention; Figure 3 It is a schematic diagram of an oscillation waveform generated in a branch disconnection state provided by the present invention; Figure 4 is a flow chart of the steps of the method for obtaining pulse fluctuation instability provided by the present invention; Figure 5 It is a structural schematic diagram of a coal mine power supply fault diagnosis based on pulse signals provided by the present invention; Figure 6 It is a structural schematic diagram of a computer device provided by the present invention. DETAILED DESCRIPTION

[0017] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a method and system for diagnosing coal mine power supply faults based on pulse signals proposed by the present invention, its specific implementation method, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0018] Unless defined otherwise, all 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.

[0019] The specific scheme of a coal mine power supply fault diagnosis method and system based on pulse signals provided by the present invention is described in detail below with reference to the accompanying drawings.

[0020] The specific scenario targeted by the present invention is: in the process of monitoring power supply failures in coal mines, due to the existence of different circuit branches in the coal mine, various mining equipment are connected on different branches. At the moment when the switches of each branch are opened and closed, due to the large power consumption of the mining equipment, voltage surges will be generated, which will cause an instantaneous increase in voltage. Therefore, when conducting power consumption detection of coal mine cables, it is necessary to eliminate the power interference caused by the voltage surge of the branch.

[0021] The main purpose of the present invention is to distinguish the pulse signals by analyzing the different manifestations of the reflected waves of the pulse signals in the circuit, reduce the influence of the voltage surge generated by the mining equipment in the coal mine at the moment of opening and closing, thereby reducing the misjudgment of the power supply fault of the cable caused by the uneven fluctuation of the reflected waves of the pulse signals, and improve the accuracy of the pulse signal in diagnosing the power supply fault of the coal mine.

[0022] See also Figure 1 , which shows a flow chart of a method for diagnosing coal mine power supply faults based on pulse signals provided by an embodiment of the present invention, the method comprising the following steps: Step S100, obtaining a main line pulse signal of a coal mine power supply line and a branch pulse signal in a disconnected state of each branch.

[0023] A pulse generator is set on the main line of the coal mine power supply cable line, which is used for the pulse signal of the cooking machine cable line. In this embodiment, the fault analysis is mainly carried out on the voltage change after the branch is disconnected, so the pulse signals involved in this embodiment are all voltage pulses, and the instantaneous signal value at each moment in the pulse signal is the instantaneous voltage value corresponding to each moment. And the pulse parameters of the pulse signal are recorded in real time, including the amplitude (pulse voltage peak), width and frequency and the reflection time of the pulse signal. The acquisition is real-time acquisition, and the acquisition frequency is 10khz. At the same time, the route line distance length and the reflection wave response time are acquired.

[0024] It should be noted that this embodiment uses the FPG225 pulse generator, which is mainly composed of a main control unit, a low-noise phase delay module, a low-jitter pulse generation module, and a linear power supply module. Through ultra-high frequency resolution control technology and low-noise signal processing technology, it can achieve femtosecond-level phase, period, and pulse width adjustment, and at the same time, it also has a PPS recording function. In other embodiments, the implementer can make a selection according to the specific implementation scenario.

[0025] Specifically, first, the original reflected wave is obtained through the pulse generator, that is, when all branches are connected, the pulse signal emitted by the pulse generator in the main line is used to obtain the reflected wave reflected by the pulse signal after it propagates through the line to each branch terminal, and the original reflected wave is obtained, which is recorded as the main line pulse signal.

[0026] Randomly select a branch connected to the main line, disconnect the branch from the main line, and obtain the reflected wave after the branch is disconnected through the pulse generator, which is recorded as the branch pulse signal in the disconnected state of the branch. At the same time, obtain the time node of disconnecting the branch to provide a data basis for subsequent signal fluctuation analysis.

[0027] It should be noted that by controlling the switch state of the branch through the control variable, the reflected wave contribution of each branch can be separated to achieve difference analysis. In some embodiments, the implementer can also disconnect the branch in a specific order (such as binary tree search) to reduce the detection blind area. It is understandable that in order to avoid noise affecting the data analysis results, the collected pulse signal can be filtered. The filtering method is a well-known technology and will not be introduced in detail here.

[0028] Step S200, based on the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal, filter out the signal fluctuation time period corresponding to the disconnection state of each branch.

[0029] When the line is intact, the voltage in the line is stable, the pulse signal propagates evenly in the line, and its reflected wave shows a uniform and stable fluctuation characteristic. When the line is damaged, the line at the damaged point is uneven, the local resistance increases, and the voltage increases abnormally, which will cause the reflected wave waveform of the line to show abnormal changes. However, in the power supply system of the coal mine, because the electrical equipment in the coal mine has a large power consumption, the equipment will produce huge voltage changes at the moment of opening and closing, which will cause voltage surges in the circuit, causing the local voltage on the line to increase instantly, which will cause uneven changes in the reflected wave on the line. Therefore, by controlling the switch of the branch, a new reflected wave with a voltage surge generated at the moment of opening and closing the branch is obtained, and the difference in the reflected waves is calculated and compared to obtain the difference in the reflected wave bands.

[0030] Considering that the surge impact area refers to the reflected wave difference time period caused by the voltage surge caused by the branch switch operation. By analyzing the time comparison between the local pulse difference generated during the disconnection of each branch and the voltage fluctuation in the main line, the voltage surge fluctuation phenomenon caused by the opening and closing of the branch equipment in the line can be eliminated, and the signal fluctuations in some other time periods can be screened out, so as to further analyze whether these fluctuating signal segments are caused by voltage surges or line faults.

[0031] Specifically, by simulating the situation where any branch is disconnected, how to eliminate the influence of the voltage surge caused by the disconnection on the line fault detection when one branch is disconnected.

[0032] In some embodiments, Figure 2 As shown, the method for acquiring the signal fluctuation time period can be implemented by steps S201 to S203.

[0033] Step S201, determining the theoretical pulse time length of the branch based on the distance between the branch and the main line pulse generator and the pulse signal transmission speed.

[0034] When the branch switch is disconnected, the pulse signal starts from the pulse generator of the main line, propagates to the branch switch position, and then reflects back to the pulse generator. When the distance from the branch switch to the pulse generator and the propagation speed of the pulse signal are known, the theoretical reflection time of the whole process can be calculated, which can be specifically expressed as: ,in represents the theoretical pulse time length of the ath branch, represents the distance from the a-th branch switch to the pulse generator, Indicates the propagation speed of the pulse signal.

[0035] Step S202, based on the branch disconnection time node and the theoretical pulse time length, determine the surge time period in the branch disconnection state.

[0036] Taking the ath branch as an example, the time period from the time node when the ath branch is disconnected to the theoretical pulse time length of the ath branch can be regarded as the surge influence area corresponding to the pulse signal, that is, the pulse signal difference time period caused by the voltage surge caused by the disconnection operation of the ath branch.

[0037] Step S203, obtaining a signal fluctuation time period corresponding to the branch disconnection state according to the time period of the difference between the signal value between the branch pulse signal corresponding to the branch and the main line pulse signal and the time difference between the surge time period.

[0038] The signal fluctuation during the surge period of the branch can be regarded as the signal fluctuation phenomenon caused by the voltage surge caused by the branch disconnection operation, while the signal fluctuation phenomenon outside the surge period requires further fluctuation characteristic analysis to distinguish the impact of voltage surge or voltage fault.

[0039] Specifically, taking the ath branch as an example, the first step is to determine the pulse difference signal corresponding to each moment of the branch pulse signal based on the difference in signal values ​​at the same moment between the main line pulse signal and the branch pulse signal corresponding to the branch disconnection.

[0040] Considering that the time lengths of the reflected wave bands are the same, the signal values ​​at the same time can be directly subtracted to obtain the pulse difference signal corresponding to the a-th branch at each time. The larger the value of the pulse difference signal, the greater the impact of the voltage surge fluctuation or the fault voltage fluctuation.

[0041] Considering that the surge period is affected by voltage surge, the voltage fluctuation in this period is not analyzed. Only the pulse difference signal at each moment meets the threshold requirement is analyzed for other moments outside the surge period. That is, outside the surge period, the continuous time period in which the value of the pulse difference signal at each moment meets the threshold requirement is obtained as the signal fluctuation time period corresponding to the branch disconnection state.

[0042] In this embodiment, for the ath branch, when the value of the pulse difference signal at a certain moment is not 0, it means that there is a signal fluctuation between the main line pulse signal and the branch pulse signal, and further analysis is needed on the cause of the signal fluctuation. Specifically, the time period consisting of all consecutive moments when the value of the pulse difference signal is not 0 is obtained as the signal fluctuation time period corresponding to the disconnection state of the ath branch. The signal fluctuation time period represents the time period in which the voltage fluctuation caused by the branch disconnection operation occurs.

[0043] Step S300, based on the degree of fluctuation of the signal value difference of the branch pulse signal corresponding to each branch within the signal fluctuation time period, combined with the difference between the actual time and theoretical time of each branch disconnection operation, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained.

[0044] When the ath branch is disconnected, the high-power mining electrical equipment connected to the ath branch is disconnected. Due to the inductance in the line, a voltage surge will be generated in the line, causing an instantaneous voltage surge on the line. The voltage amplitude is significantly higher than the voltage level when the system is operating normally. This voltage surge phenomenon is instantaneous and lasts for a very short time. Based on this, the reflected wave is affected by the voltage change, and will also produce instantaneous abnormal fluctuations. After the incident wave and the reflected wave surge voltage are superimposed, a periodic oscillation waveform is formed at a specific position of the transmission line, such as Figure 3 As shown, the reflected wave presents a specific fluctuation. Because of the instantaneous voltage surge, the reflected wave will surge instantly and the peak amplitude of the fluctuation will gradually decrease with time. Because the ath branch is disconnected, at the open circuit terminal, the reflected wave and the incident wave are in the same phase, and the same phase is superimposed, and the fluctuation amplitude of the reflected wave increases.

[0045] Based on this feature, by analyzing the difference between the actual occurrence time and the theoretical occurrence time in the time period when there is a signal difference after a branch is disconnected, and combining the analysis of the signal value attenuation over time, it is possible to quantify whether there is an abnormality in the voltage fluctuation occurring in this time period, and quantify the pulse fluctuation instability in the signal fluctuation time period corresponding to the voltage fluctuation.

[0046] In some embodiments, Figure 4As shown, the method for obtaining pulse fluctuation instability can be implemented by steps S301 to S303.

[0047] Step S301, obtaining the position attribution of the disconnection state of each branch according to the difference between the theoretical pulse time length corresponding to each branch and the actual duration length of the disconnection operation of each branch.

[0048] In step S201, the theoretical pulse real time length corresponding to each branch is obtained, which represents the impact time length of the voltage fluctuation theoretically generated by the branch disconnection operation under theoretical conditions. The actual impact time length is further obtained by actually monitoring the time performance of the pulse signal mutation after the branch disconnection operation, and then the difference between theory and practice is compared.

[0049] Specifically, taking any branch disconnection operation as an example, for the ath branch, the pulse difference signal corresponding to each moment of the branch pulse signal is fitted to obtain the difference signal curve of the branch, and the first signal mutation point of the difference signal curve is obtained, and the time length between the branch disconnection time node and the signal mutation point is used as the actual pulse time length of the branch disconnection. Among them, the mutation point of the pulse signal can be obtained by wavelet transform and other algorithms, which is a well-known technology and will not be introduced in detail here.

[0050] It can be understood that on the difference signal curve, the location of the first signal mutation point can be regarded as the voltage mutation phenomenon caused by the branch disconnection operation, that is, the time point when the branch disconnection operation actually produces voltage fluctuations during the actual monitoring of the pulse signal.

[0051] Further, based on the negative correlation coefficient of the difference between the theoretical pulse time length and the actual pulse time length corresponding to the branch, the position attribution of the branch disconnection state is determined. As a specific example, the calculation formula for the position attribution of the a-th branch disconnection state can be expressed as: ,in Indicates the location attribution of the disconnected state of the a-th branch, represents the theoretical pulse time length of the ath branch, represents the actual pulse time length of the ath branch, Represents an exponential function with the natural constant e as the base.

[0052] It indicates the difference between the theoretical and actual pulse practice lengths after the a-th branch is disconnected. The smaller the difference, the higher the correlation between the voltage fluctuation of the branch and the branch disconnection event. The possibility of voltage surge at the moment of branch disconnection is greater, and the corresponding position attribution degree is greater. The position attribution degree corresponding to the branch reflects, to a certain extent, the possibility of voltage surge generated by the corresponding branch disconnection operation.

[0053] Step S302, according to the difference of adjacent signal values ​​of the branch pulse signal corresponding to each branch in each signal fluctuation time period, combined with the position attribution, the disconnection pulse attenuation degree of each branch in each signal fluctuation time period is obtained.

[0054] Taking into account the voltage fluctuation phenomenon caused by the voltage surge generated by the branch disconnection, the instantaneous voltage of the pulse signal generally shows the instantaneous attenuation and duration. By analyzing the performance of the pulse signal in these two aspects in each signal fluctuation time period when the branch is disconnected, and combining the possibility of generating a voltage surge represented by the position attribution, the degree of attribution of the signal attenuation when the circuit is disconnected in each signal fluctuation time period is quantified.

[0055] Specifically, for any branch, the first characteristic coefficient of each signal fluctuation time period is determined based on the inverse of the time length of the branch in each signal fluctuation time period and the position attribution degree; the cumulative sum of the signal value differences of the branch pulse signal at every two adjacent moments in each signal fluctuation time period is taken as the second characteristic coefficient of each signal fluctuation time period; the circuit breaker pulse attenuation degree of each signal fluctuation time period is obtained according to the first characteristic coefficient and the second characteristic coefficient, and the circuit breaker pulse attenuation degree is a normalized value.

[0056] As a specific example, the calculation formula of the disconnection pulse attenuation of the a-th branch in the i-th signal fluctuation time period can be expressed as: ; in, It represents the attenuation of the disconnection pulse of the a-th branch in the i-th signal fluctuation time period, Indicates the location attribution of the disconnected state of the a-th branch, It represents the time length of the a-th branch in the i-th signal fluctuation period, It represents the signal value of the branch pulse signal of the a-th branch at the x-th moment in the i-th signal fluctuation time period. It represents the signal value of the branch pulse signal of the a-th branch at the x+1th moment in the i-th signal fluctuation time period. is the normalization function.

[0057] is the first characteristic coefficient. The larger its value is, the greater the possibility that the pulse difference may be caused by the disconnection of the ath branch during the current signal fluctuation period. The smaller the value, The larger the value is, the more emphasis is placed on the rapid attenuation characteristics of transient surges. It reflects the position matching, that is, the degree of attribution, and considers the position matching and time scale at the same time to ensure that only the signal segments with high correlation and rapid decay have corresponding attenuation degrees that are larger.

[0058] is the second characteristic coefficient, It reflects the difference in signal values ​​at adjacent moments during the signal fluctuation period. When , it means that the signal value decays over time during the signal fluctuation period, which is consistent with the typical characteristics of normal surge. It means that the signal value increases with time during the signal fluctuation period. At this time, the degree of surge characteristic is smaller, and it is more likely to be fault interference, and the value of the second characteristic coefficient is smaller.

[0059] The final circuit-breaking pulse attenuation represents the degree of characteristic performance of the signal fluctuation caused by surge in the corresponding signal fluctuation period. The larger the value, the more likely the voltage fluctuation in the corresponding signal fluctuation period is caused by voltage surge. The smaller the value, the more likely the voltage fluctuation in the corresponding signal fluctuation period is caused by voltage fault.

[0060] Step S303, obtaining the pulse fluctuation instability of each branch in each signal fluctuation time period according to the disconnection pulse attenuation of each branch in each signal fluctuation time period and the signal value fluctuation degree of the branch pulse signal in each signal fluctuation time period.

[0061] Considering that if there is a fault in the line, such as damage, moisture, etc., the local resistance suddenly increases and the voltage rises abnormally, which is reflected in the violent fluctuation in the pulse signal. In addition, unlike the instantaneous attenuation characteristics of the surge during the line fault, the pulse fluctuation caused by the fault usually lasts for a long time, thereby causing the signal value variance within this certain period of time to remain high.

[0062] Based on this feature, for any branch, the product of the negative correlation coefficient of the disconnection pulse attenuation in each signal fluctuation time period and the signal value variance of all branch pulse signals in the same signal fluctuation time period is normalized to obtain the pulse fluctuation instability in each signal fluctuation time period.

[0063] In this embodiment, the inverse of the attenuation of the disconnection pulse of the a-th branch in the i-th signal fluctuation time period is calculated as the negative correlation coefficient. It can be understood that this embodiment adopts The function is normalized, and the range of the normalized disconnection pulse attenuation is (0,1). More specifically, the pulse fluctuation instability of the a-th branch in the i-th signal fluctuation time period is It can be expressed as , It represents the attenuation of the disconnection pulse of the a-th branch in the i-th signal fluctuation time period, It represents the variance of the signal values ​​of all branch pulse signals of the a-th branch in the i-th signal fluctuation time period.

[0064] When a line fault occurs, such as line damage, the local resistance at that position increases, the voltage increases, and the pulse signal fluctuates unevenly. The reflected wave pulse signal changes, and the variance of the pulse signal value increases. Since the fault is not instantaneous, the pulse signal value will not decay instantaneously. Therefore, the greater the fluctuation of the pulse signal value within the signal fluctuation time period, the greater the pulse fluctuation instability of the reflected wave within the signal fluctuation time period, that is, the possibility of a line fault at the location of the ath branch within the signal fluctuation time period is greater.

[0065] At this point, the pulse fluctuation instability corresponding to each signal fluctuation time period in each branch disconnected state can be obtained according to the same method, which represents the possibility of a fault occurring in the signal fluctuation time period when the corresponding branch is disconnected.

[0066] Step S400, analyzing and obtaining the fault diagnosis result of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period.

[0067] When the value of pulse fluctuation instability of each branch in each signal fluctuation time period is larger, it means that when the corresponding branch is disconnected, the location of the corresponding branch is more likely to have a fault in the signal fluctuation time period, and the branch needs to be repaired. When the value of pulse fluctuation instability of each branch in each signal fluctuation time period is smaller, it means that when the corresponding branch is disconnected, the location of the corresponding branch is less likely to have a fault in the signal fluctuation time period, and this may be due to voltage fluctuations caused by other objective environmental factors such as noise or surge.

[0068] Based on this, when the pulse fluctuation instability of each signal fluctuation time period of each branch is less than the preset abnormal threshold, the coal mine power supply line has not failed, indicating that the pulse signal at this time is relatively stable and the current line is in normal power supply condition. When the pulse fluctuation instability of each signal fluctuation time period of each branch is greater than or equal to the preset abnormal threshold, the coal mine power supply line has failed, indicating that there is a high possibility of line damage or line failure caused by mechanical vibration or external force factors on the line of the corresponding branch at this time, which makes the reflected wave pulse signal of the branch in this time period more unstable. In this embodiment, the value of the abnormal threshold is 0.8, and the implementer can set it according to the specific implementation scenario.

[0069] In some embodiments, when a fault is detected in the coal mine power supply line, the location of the fault point can be determined based on the pulse fluctuation time length corresponding to the fault. Specifically, for any signal fluctuation time period where the fault occurs, the signal propagation length is determined based on the product of the propagation speed of the pulse signal and the time length of the signal fluctuation time period, and the location of the fault point is determined using half of the signal propagation length.

[0070] More specifically, for any branch, the product of the propagation speed of the pulse signal and the length of the signal fluctuation time period of the branch when the threshold is met is calculated to obtain the signal propagation length of the branch, and the position where the signal propagation length is half the distance from the pulse generator is obtained as the location of the fault point, so that relevant workers can be notified to perform troubleshooting.

[0071] It should be noted that this embodiment aims to eliminate the voltage surge phenomenon in the line after the branch switch is instantly cut off, which affects the judgment result of the line fault and improves the accuracy of the line fault detection result. On the basis of the judgment result, the location of the fault point can be preliminarily determined, which shortens the scope of manual troubleshooting and reduces part of the workload.

[0072] To summarize, the present invention calculates the impact of voltage changes under different line switch states on each branch on the reflected wave on the line, and then separates the impact of surge phenomena generated by each branch on the pulse signal fluctuation, thereby obtaining the true signal value performance of the line, and then judging the line fault on the line. Compared with the prior art, the interference of voltage surges generated by voltage changes in the branches is eliminated, and the true pulse signal fluctuation on the line is obtained, which can better perform coal mine power supply fault diagnosis and improve the accuracy of fault diagnosis.

[0073] In some embodiments, Figure 5As shown, a coal mine power supply fault diagnosis system based on pulse signals is provided, and the system is used to implement the steps of a coal mine power supply fault diagnosis method based on pulse signals. The coal mine power supply fault diagnosis system based on pulse signals specifically includes: A data acquisition module, used to acquire the main line pulse signal of the coal mine power supply line and the branch pulse signal of each branch in the disconnected state; A data preprocessing module, used to screen out the signal fluctuation time period corresponding to the disconnection state of each branch according to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal; The instability analysis module is used to obtain the pulse fluctuation instability of each branch in each signal fluctuation time period according to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and theoretical time of the disconnection operation of each branch; The fault diagnosis module is used to analyze and obtain the fault diagnosis results of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period.

[0074] The present application also provides a computer device. Figure 6 , which shows a schematic diagram of the structure of a computer device provided by an embodiment of the present invention, the computer device includes a memory 601, a processor 602, and a computer program 603 stored in the memory 601 and running on the processor 602, wherein when the processor 602 executes the computer program 603, the computer device can execute the above-mentioned coal mine power supply fault diagnosis method based on pulse signals.

[0075] An embodiment of the present application also provides a computer program product. When the computer program product is run on a computer device, the computer device can execute the above-mentioned coal mine power supply fault diagnosis method based on pulse signals.

[0076] An embodiment of the present application also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer device, the computer device can execute the above-mentioned coal mine power supply fault diagnosis method based on pulse signals.

[0077] In the embodiments provided in the present application, it should be understood that the provided computer device, computer program product and computer-readable storage medium are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the methods provided above and will not be repeated here.

[0078] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A coal mine power supply fault diagnosis method based on pulse signals, characterized in that: The method comprises the following steps: Obtain the main line pulse signal of the coal mine power supply line and the branch pulse signal of each branch in the disconnected state; According to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal, the signal fluctuation time period corresponding to the disconnection state of each branch is screened out; According to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and theoretical time of the disconnection operation of each branch, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained; According to the pulse fluctuation instability of each branch in each signal fluctuation time period, the fault diagnosis results of the coal mine power supply line are analyzed and obtained.

2. A coal mine power supply fault diagnosis method based on pulse signals according to claim 1, characterized in that: The method of screening out the signal fluctuation time period corresponding to the disconnection state of each branch according to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal specifically includes: For any branch, the theoretical pulse time length of the branch is determined based on the distance between the branch and the main line pulse generator and the pulse signal transmission speed; Determine the surge time period in the branch disconnection state based on the branch disconnection time node and the theoretical pulse time length; According to the time difference between the time period in which the signal value difference between the branch pulse signal corresponding to the branch and the main line pulse signal is located and the surge time period, the signal fluctuation time period corresponding to the branch disconnection state is obtained.

3. A coal mine power supply fault diagnosis method based on pulse signal according to claim 2, characterized in that: The obtaining of the signal fluctuation time period corresponding to the branch disconnection state according to the time difference between the signal value difference between the branch pulse signal corresponding to the branch and the main line pulse signal and the surge time period specifically includes: For any branch, based on the difference in signal values ​​at the same time between the main line pulse signal and the branch pulse signal corresponding to the branch disconnection, determine the pulse difference signal corresponding to each moment of the branch pulse signal; Outside the surge time period, a continuous time period in which the value of the pulse difference signal at each moment meets the threshold requirement is obtained as a signal fluctuation time period corresponding to the branch disconnection state.

4. A coal mine power supply fault diagnosis method based on pulse signal according to claim 2, characterized in that: The pulse fluctuation instability of each branch in each signal fluctuation time period is obtained based on the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and the theoretical time of the disconnection operation of each branch, and specifically includes: According to the difference between the theoretical pulse time length corresponding to each branch and the actual duration length of each branch disconnection operation, the position attribution degree of each branch disconnection state is obtained; According to the difference of adjacent signal values ​​of the branch pulse signal corresponding to each branch in each signal fluctuation time period, combined with the position attribution degree, the disconnection pulse attenuation degree of each branch in each signal fluctuation time period is obtained; According to the disconnection pulse attenuation of each branch in each signal fluctuation time period and the signal value fluctuation degree of the branch pulse signal in each signal fluctuation time period, the pulse fluctuation instability of each branch in each signal fluctuation time period is obtained.

5. A coal mine power supply fault diagnosis method based on pulse signals according to claim 4, characterized in that: The position attribution of each branch disconnection state is obtained according to the difference between the theoretical pulse time length corresponding to each branch and the actual duration length of each branch disconnection operation, specifically including: For any branch, the pulse difference signal corresponding to each moment of the branch pulse signal is fitted to obtain the difference signal curve of the branch, the first signal mutation point of the difference signal curve is obtained, and the time length between the branch disconnection time node and the signal mutation point is taken as the actual pulse time length of the branch disconnection; Based on the negative correlation coefficient of the difference between the theoretical pulse time length and the actual pulse time length corresponding to the branch, the position attribution of the branch disconnection state is determined.

6. A coal mine power supply fault diagnosis method based on pulse signals according to claim 4, characterized in that: The method of obtaining the disconnection pulse attenuation of each branch in each signal fluctuation time period according to the difference of adjacent signal values ​​of the branch pulse signal corresponding to each branch in each signal fluctuation time period in combination with the position attribution degree specifically includes: For any branch, based on the inverse of the length of time of the branch in each signal fluctuation time period and the position attribution degree, determine the first characteristic coefficient of each signal fluctuation time period; The accumulated sum of the differences in the signal values ​​of the branch pulse signals at every two adjacent moments in each signal fluctuation time period is used as the second characteristic coefficient of each signal fluctuation time period; The disconnection pulse attenuation degree in each signal fluctuation time period is obtained according to the first characteristic coefficient and the second characteristic coefficient, and the disconnection pulse attenuation degree is a normalized value.

7. A coal mine power supply fault diagnosis method based on pulse signals according to claim 4, characterized in that: The pulse fluctuation instability of each branch in each signal fluctuation time period is obtained according to the disconnection pulse attenuation of each branch in each signal fluctuation time period and the signal value fluctuation degree of the branch pulse signal in each signal fluctuation time period, specifically including: For any branch, the product of the negative correlation coefficient of the disconnection pulse attenuation in each signal fluctuation time period and the signal value variance of all branch pulse signals in the same signal fluctuation time period is normalized to obtain the pulse fluctuation instability in each signal fluctuation time period.

8. A coal mine power supply fault diagnosis method based on pulse signals according to claim 1, characterized in that: The method of analyzing and obtaining the fault diagnosis result of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period specifically includes: When the pulse fluctuation instability of each signal fluctuation time period of each branch is less than the preset abnormal threshold, the coal mine power supply line has not failed; When the pulse fluctuation instability of each signal fluctuation time period of each branch is greater than or equal to a preset abnormal threshold, a coal mine power supply line fails.

9. A method for diagnosing coal mine power supply faults based on pulse signals according to claim 8, characterized in that: When a coal mine power supply line fails, the method further comprises: For any signal fluctuation time period where a fault occurs, the signal propagation length is determined based on the product of the propagation speed of the pulse signal and the time length of the signal fluctuation time period, and the location of the fault point is determined using half of the signal propagation length.

10. A coal mine power supply fault diagnosis system based on pulse signals, characterized in that: The system is used to implement the steps of a coal mine power supply fault diagnosis method based on pulse signals as described in any one of claims 1 to 9, and the coal mine power supply fault diagnosis system based on pulse signals specifically includes: A data acquisition module, used to acquire the main line pulse signal of the coal mine power supply line and the branch pulse signal of each branch in the disconnected state; A data preprocessing module, used to screen out the signal fluctuation time period corresponding to the disconnection state of each branch according to the time difference and signal value difference between the branch pulse signal corresponding to each branch and the main line pulse signal; The instability analysis module is used to obtain the pulse fluctuation instability of each branch in each signal fluctuation time period according to the fluctuation degree of the signal value difference of the branch pulse signal corresponding to each branch in the signal fluctuation time period, combined with the difference between the actual time and theoretical time of the disconnection operation of each branch; The fault diagnosis module is used to analyze and obtain the fault diagnosis results of the coal mine power supply line according to the pulse fluctuation instability of each branch in each signal fluctuation time period.

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