Ring network box for remote status perception

Abstract

The present application relates to the technical field of power transmission and distribution equipment, and specifically to a ring network box that facilitates remote state perception, including: an ultrasonic signal acquisition module to obtain the ultrasonic signal of the ring network box and the concentration of the insulating gas inside the ring network box; an ultrasonic signal analysis module to construct the degree of energy distribution concentration and the matching degree of waveform characteristics to obtain the partial discharge confidence; construct the scattering attenuation step coefficient inside the ring network box, correct the partial discharge confidence, calculate the step adjustment index, determine the adaptive step factor of the ultrasonic signal, and use the adaptive filtering algorithm to obtain a pure ultrasonic signal; a partial discharge identification module to determine the type and location of the ring network box fault; a wireless communication module to send the fault type and location to the control center through wireless communication technology to remotely perceive the working condition of the ring network box; a display module to visualize the working condition of the ring network box using a liquid crystal display. The present application improves the state perception accuracy of the ring network box.

Description

Technical Field

[0001] The present application relates to the technical field of power transmission and distribution equipment, and in particular to a ring network box that facilitates remote status perception. Background Art

[0002] Ring network box, also known as ring network cabinet, is a closed equipment. Ring network box failure is usually caused by insulation degradation and damage during operation. Partial discharge is an important reason for insulation degradation of ring network box. The ultrasonic partial discharge detection method receives ultrasonic pulses generated by partial discharge inside the ring network box. It has strong spatial propagation and is less affected by electrical interference during the operation of the ring network box. It can realize the identification and positioning of partial discharge of the ring network box. However, the ultrasonic partial discharge detection method is easily interfered by the noise of the construction environment and mechanical vibration. The ultrasonic signal finally obtained is inevitably mixed with a certain amount of noise components, which will greatly interfere with the results of ultrasonic detection.

[0003] The LMS (Least Mean Squares) adaptive filtering algorithm is simple and efficient. It removes noise by continuously adjusting the filter coefficients. However, the performance of the LMS algorithm is highly dependent on the choice of the step factor, which is usually set to a fixed value based on experience. However, under different working conditions of the ring network box, the attenuation of ultrasonic signals is inconsistent, and the noise interference outside the ring network box is also random. There is a situation where ultrasonic signals and noise signals cannot be distinguished. The fixed step factor is difficult to adapt to the complex and changeable actual working conditions of the ring network box, which can easily cause excessive noise reduction and incomplete noise reduction. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a ring network box that facilitates remote status perception. The technical solutions adopted are as follows:

[0005] The present application proposes a ring network box that facilitates remote status perception, and the ring network box includes:

[0006] Ultrasonic signal acquisition module, used to obtain the ultrasonic signal of the ring network box and the concentration of insulating gas inside the ring network box;

[0007] The ultrasonic signal analysis module performs frame processing on the ultrasonic signal to obtain each ultrasonic signal frame, analyzes the frequency difference and bandwidth corresponding to the spectrum peak of each ultrasonic signal frame in the frequency domain, so as to obtain the energy distribution concentration degree of each ultrasonic signal frame; based on the amplitude change trend in the neighborhood of the maximum amplitude data point in each ultrasonic signal frame and the amplitude strength of all data points of the ultrasonic signal frame, obtains the waveform feature matching degree of each ultrasonic signal frame, and obtains the partial discharge confidence of each ultrasonic signal frame in combination with the energy distribution concentration degree;

[0008] According to the discrete degree of the insulating gas concentration inside the ring network box and the difference between the average level of the insulating gas concentration inside the ring network box and the preset insulating gas concentration factory inspection value, the scattering attenuation step coefficient inside the ring network box is obtained to correct the partial discharge confidence to obtain the partial discharge correction confidence of each ultrasonic signal frame;

[0009] According to the frequency and energy distribution of the spectrum graph corresponding to each ultrasonic signal frame and the confidence of partial discharge correction, the step adjustment index of each ultrasonic signal frame is obtained, the adaptive step factor of the ultrasonic signal is determined according to the average level of the step adjustment index of all ultrasonic signal frames in the ultrasonic signal, and the adaptive filtering algorithm is used to obtain a pure ultrasonic signal;

[0010] The partial discharge identification module is used to obtain the fault type and location of the ring main box using the partial discharge spectrum according to the pure ultrasonic signal of the ring main box;

[0011] A wireless communication module is used to send the fault type and location of the ring network box to the control center through wireless communication technology, and the control center remotely senses the working condition of the ring network box;

[0012] The display module is used to receive the fault type and location of the ring network box and visualize the working condition of the ring network box using an LCD liquid crystal display screen.

[0013] Preferably, the energy distribution concentration degree of each ultrasonic signal frame is calculated by: ; Where E is the energy distribution concentration of the ultrasonic signal frame, are the frequencies corresponding to the sth and s-1th peak points in the spectrum peak sequence of the ultrasonic signal frame, are the frequency bandwidths corresponding to the sth and s-1th peak points in the spectrum peak sequence of the ultrasonic signal frame, respectively. S is the number of peak points in the spectrum graph of the ultrasonic signal frame, wherein all peak points of the spectrum graph of the ultrasonic signal frame are arranged in ascending order of frequency to form the spectrum peak sequence of the ultrasonic signal frame.

[0014] Preferably, the waveform feature matching degree of each ultrasonic signal frame is calculated by:

[0015] ; In the formula, is the waveform feature matching degree of the ultrasonic signal frame, is the cumulative sum of the square values ​​of the amplitudes of all data points in the ultrasonic signal frame, is an exponential function with a natural constant as base, It is the trend statistic of the amplitude sequence of the ultrasonic signal frame, wherein the amplitude sequence is constructed according to the amplitudes of all data points in the neighborhood of the data point where the maximum amplitude of the ultrasonic signal frame is located, and the trend statistic of the amplitude sequence is obtained by a trend test algorithm.

[0016] Preferably, the construction of the amplitude sequence includes:

[0017] Taking the data point with the largest amplitude in the ultrasonic signal frame as the starting point, all data points within a preset time length are selected to the right, and the amplitudes of all selected data points are arranged in ascending order of time of the data points to form an amplitude sequence.

[0018] Preferably, the partial discharge confidence of each ultrasonic signal frame is the product of the energy distribution concentration degree of each ultrasonic signal frame and the waveform feature matching degree.

[0019] Preferably, the corresponding calculation method of the scattering attenuation step coefficient inside the ring network box is:

[0020] ; In the formula, is the scattering attenuation compensation coefficient inside the ring network box, is the standard deviation of the insulating gas concentration series inside the ring main box, is the mean value of the insulating gas concentration sequence inside the ring network box, The factory inspection value of the insulating gas concentration inside the ring network box is preset, wherein the insulating gas concentration inside the ring network box at all acquisition moments constitutes the insulating concentration sequence inside the ring network box.

[0021] Preferably, the partial discharge correction confidence of each ultrasonic signal frame is a normalized value of the product of the partial discharge confidence of each ultrasonic signal frame and a scattering attenuation compensation coefficient.

[0022] Preferably, the step size adjustment index of each ultrasonic signal frame is calculated as follows:

[0023] ; In the formula, is the step size adjustment index of the ultrasound signal frame, is the Jaccard distance, is the confidence level of partial discharge correction of the ultrasonic signal frame, To prevent the denominator from being a constant of 0, Norm[] is a normalization function. They are respectively the high-energy and high-frequency set of partial discharge and the high-energy and high-frequency set of ultrasonic signal frames.

[0024] Preferably, the method for acquiring the high-energy and high-frequency set of partial discharge and the high-energy and high-frequency set of ultrasonic signal frames further comprises:

[0025] The frequencies in the spectrum of the ultrasonic signal frame that are greater than a preset threshold are regarded as high frequencies, and the high frequencies that belong to the frequency bandwidth corresponding to the 3dB bandwidth of any peak point are recorded as high-energy high frequencies, and all high-energy high frequencies are composed of a high-energy high frequency set of the ultrasonic signal frame;

[0026] The partial discharge correction confidences of all ultrasonic signal frames are arranged in descending order, and the intersection of the high-energy and high-frequency sets of the first preset number of ultrasonic signal frames is used as the partial discharge high-energy and high-frequency set.

[0027] Preferably, the adaptive step size factor of the ultrasonic signal is calculated as follows: ; In the formula, is the adaptive step size factor of the ultrasonic signal, is the step-size adjusted exponential mean of all ultrasound signal frames of the ultrasound signal, is the maximum value of the step size factor in the adaptive filtering algorithm, and its value is the maximum eigenvalue of the autocorrelation matrix of the ultrasonic signal.

[0028] This application has the following beneficial effects:

[0029] The present application constructs a scattering attenuation compensation coefficient by deeply analyzing the uniformity of the gas medium inside the ring network box and the degree of decomposition of the insulating gas. The beneficial effect is to compensate for the local discharge ultrasonic signal of the ring network box with a high degree of scattering attenuation, so as to avoid the serious energy attenuation of the local discharge ultrasonic signal and the low confidence of the local discharge caused by the high degree of scattering attenuation, and to avoid excessive noise reduction in the subsequent LMS adaptive filtering, which causes a large number of details of the local discharge ultrasonic signal to be lost, thereby improving the accuracy of the ring network box status perception;

[0030] At the same time, the present application identifies the additional echo of the partial discharge ultrasonic signal of the ring network box and constructs the step adjustment index of the ultrasonic signal frame. The beneficial effect is to give the additional echo ultrasonic signal a larger step factor, improve the convergence speed of the LMS algorithm, and reduce the interference of the additional echo ultrasonic signal on the partial discharge of the ring network box.

[0031] Furthermore, according to the actual working conditions of the ring main box, the step size factor of the LMS algorithm is adaptively determined, so as to improve the convergence speed of the LMS algorithm and the real-time performance of the state perception of the ring main box while retaining the detailed characteristics of the partial discharge ultrasonic signal in a targeted manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A block diagram of a ring network box for facilitating remote status perception provided by an embodiment of the present application;

[0034] Figure 2A schematic diagram of ultrasonic signal acquisition provided by an embodiment of the present application;

[0035] Figure 3 A schematic diagram of an additional echo propagation path of an ultrasonic sensor provided in one embodiment of the present application;

[0036] Figure 4 A flow chart of denoising the ultrasonic signal of a ring network box provided in one embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of the ring network box for facilitating remote status perception proposed by the present application in combination 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.

[0038] 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 application belongs.

[0039] The specific scheme of the ring network box that facilitates remote status perception provided by the present application is described in detail below with reference to the accompanying drawings.

[0040] See also Figure 1 , which shows a block diagram of a ring network box that facilitates remote status perception provided by an embodiment of the present application. The system includes: an ultrasonic signal acquisition module, an ultrasonic signal analysis module, a partial discharge identification module, a wireless communication module, and a display module.

[0041] Ultrasonic signal acquisition module: used to obtain the ultrasonic signal of the ring network box and the concentration of insulating gas inside the ring network box.

[0042] The ring network box is a closed device that uses insulating gas as the insulating medium. When local discharge occurs inside the ring network box, the violent collision between the surrounding molecules excites ultrasonic signals and propagates inside the ring network box. The signal frequency range is 20kHz to 200kH. In this embodiment, ultrasonic sensors are fixed at the center positions of the two side surfaces outside the ring network box cabinet to receive ultrasonic signals. The frequency response width of the ultrasonic sensor, that is, the signal frequency range collected during the ultrasonic sensor detection process, is 20kHz to 200kHz, and the sampling time is 10s to obtain the ultrasonic signal of the ring network box; and a gas monitoring device is installed at the center position just above the inside of the ring network box to measure the insulating gas concentration data inside the ring network box. The sampling frequency is 5Hz and the sampling time is 10s to obtain the insulating gas concentration sequence inside the ring network box. Figure 2 For the collection diagram, Figure 2 Among them, number 101 is the ring network box cabinet, number 102 is the local discharge inside the ring network box, number 103 is the sound field caused by the local discharge inside the ring network box, number 104 is the ultrasonic sensor, and number 105 is the gas monitoring equipment.

[0043] At this point, the ultrasonic signal of the ring main box and the concentration sequence of the insulating gas inside the ring main box can be obtained. The ultrasonic signal acquisition module transmits the ultrasonic signal received by the ultrasonic sensor to the ultrasonic signal analysis module through wired transmission.

[0044] Ultrasonic signal analysis module: used to denoise the ultrasonic signal of the ring network box to obtain a pure ultrasonic signal, which specifically includes three processes.

[0045] The first process includes: performing frame processing on the ultrasonic signal to obtain each ultrasonic signal frame, analyzing the frequency difference and bandwidth difference corresponding to the spectrum peak of each ultrasonic signal frame in the frequency domain to obtain the energy distribution concentration degree of each ultrasonic signal frame, based on the amplitude change trend in the neighborhood of the maximum amplitude data point in each ultrasonic signal frame and the amplitude intensity of all data points of the ultrasonic signal frame, obtaining the waveform feature matching degree of each ultrasonic signal frame, and combining the energy distribution concentration degree to obtain the local discharge confidence of each ultrasonic signal frame.

[0046] Some insulation positions in the ring network box will discharge under the action of external voltage. The discharge phenomenon in these discharge areas without a fixed discharge channel is partial discharge. Partial discharge is an important cause of insulation degradation of the ring network box. When the local discharge phenomenon accumulates to a certain extent, the insulation capacity is weakened. Therefore, it is necessary to use online monitoring technology to perceive the state of the ring network box and monitor it effectively, so as to formulate scientific measures within an effective time to prevent it and reduce the insulation failure rate of the ring network box.

[0047] Ring mainframes are widely used in factories, enterprises and construction sites. Ultrasonic technology is used for partial discharge detection. The external environment mainly contains mechanical vibration interference noise and white noise from construction or processing equipment. Among them, the energy of white noise is evenly distributed in the entire frequency domain, and the energy of partial discharge and mechanical vibration interference noise is more concentrated on the spectrum diagram, and specific frequencies have extremely high energy.

[0048] In this embodiment, an ultrasonic signal of a ring network box received by an ultrasonic sensor is taken as an example for detailed description, and the same processing can be applied to an ultrasonic signal of a ring network box received by another ultrasonic sensor.

[0049] Specifically, the ultrasonic signal of the ring network box is framed. In this embodiment, the ultrasonic signal frame length is set to 20ms, and the corresponding frame shift is 1 / 2. The ultrasonic signal of the ring network box is divided into several ultrasonic signal frames, and the ultrasonic signal frame is subjected to Fast Fourier Transformation (FFT) to output the spectrum diagram of each ultrasonic signal frame. The larger the amplitude corresponding to the frequency component, the greater the energy of the frequency component. The spectrum diagram of the ultrasonic signal frame is used as the input of the AMPD (Automatic multiscale-based peak detection) algorithm to output the peak points in the spectrum diagram of the ultrasonic signal frame. The AMPD algorithm is a well-known technology and the specific process will not be repeated. All peak points are arranged in ascending order of frequency to obtain a spectrum peak sequence. Specifically, in this embodiment, the concentration of energy distribution of the ultrasonic signal frame is obtained in the following way:

[0050] ; Where E is the energy distribution concentration of the ultrasonic signal frame, are the frequencies corresponding to the sth and s-1th peak points in the spectrum peak sequence, are the bandwidths corresponding to the sth and s-1th peak points in the spectrum peak sequence, respectively, and S is the number of peak points in the ultrasonic signal frame spectrum. The smaller the difference in the frequency values ​​of adjacent peak points in the spectrum peak sequence, that is, The smaller it is, the denser the high energy frequency distribution of the ultrasonic signal frame is; at the same time, when the peak point has significant energy in a wider frequency range, that is, The larger the value, the wider the frequency components of the ultrasonic signal frame are distributed, and the more concentrated the high energy distribution is. Its beneficial effect is to avoid the problem that all frequency energies in a small frequency range are high but the number of peak points is small. The degree of energy distribution concentration is The bigger.

[0051] At this point, the energy distribution concentration of any ultrasonic signal frame is obtained, which reflects the energy distribution concentration of the ultrasonic signal frame on the spectrum. The greater the energy distribution concentration, the less white noise components the ultrasonic signal frame contains. The energy distribution concentration of the ultrasonic signal frame can be used to eliminate the interference of white noise in the ring network box working scenario, but it is impossible to accurately distinguish between mechanical vibration interference noise and partial discharge signals.

[0052] Furthermore, in the ring network box enclosed by insulating gas, two types of local discharge faults, corona discharge and suspended discharge, are easily generated inside the ring network box, generating strong ultrasonic signals, and the time domain waveform is similar to a "trumpet shape", and the amplitude gradually decreases with time.

[0053] Therefore, in this embodiment, the data point with the largest amplitude in the ultrasonic signal frame is taken as the starting point, and all data points within the preset time length are selected to the right, and the amplitudes of all selected data points are arranged in ascending order of the time of the data points to form an amplitude sequence. It should be noted that the preset time length is 5ms in this embodiment. The amplitude sequence is used as the input of the Mann-Kendall trend test algorithm, and the trend statistic is output. The Mann-Kendall trend test algorithm is a well-known technology, and the specific process is not repeated here. The waveform feature matching degree of the ultrasonic signal frame is obtained by the following formula:

[0054] ; In the formula, is the waveform feature matching degree of the ultrasonic signal frame, is the cumulative sum of the square values ​​of the amplitudes of all data points in the ultrasonic signal frame, is the trend statistic of the amplitude sequence in the ultrasonic signal frame, is an exponential function with a natural constant as its base.

[0055] It can be understood that the larger the frame energy of the ultrasonic signal frame, the The larger the value, the stronger the ultrasonic signal frame contains in the time domain. The larger the value is, the more the ultrasonic signal frame has a decreasing amplitude trend in the time domain, and the more it conforms to the "horn-shaped" time domain waveform. The more similar the waveform characteristics of the ultrasonic signal in the ultrasonic signal frame are to those of the partial discharge ultrasonic signal, the better the waveform feature matching is. The bigger.

[0056] So far, the waveform feature matching degree of any ultrasonic signal frame is obtained, and its beneficial effect is that it combines the time-frequency waveform characteristics of the partial discharge ultrasonic signal to avoid the problem that the energy distribution concentration degree is difficult to accurately distinguish the partial discharge ultrasonic signal from the mechanical vibration interference noise. Therefore, this embodiment obtains the partial discharge confidence of the ultrasonic signal frame through the energy distribution concentration degree and waveform feature matching degree of the ultrasonic signal frame.

[0057] Specifically, in this embodiment, the normalized value of the product of the local discharge confidence of each ultrasonic signal frame and the scattering attenuation compensation coefficient is used as the local discharge confidence of each ultrasonic signal frame. It can be understood that the greater the local discharge confidence, the more likely it is that the ultrasonic signal frame contains a local discharge ultrasonic signal. When performing the LMS adaptive filtering algorithm, a smaller step factor should be used to ensure the steady-state effect of the ultrasonic signal after being processed by the LMS algorithm, avoid the phenomenon that the ultrasonic signal diverges after being processed by the LMS algorithm due to a large step factor, and retain the detailed characteristics of the local discharge ultrasonic signal.

[0058] The second process includes: according to the discrete degree of the insulating gas concentration inside the ring network box and the difference between the average level of the insulating gas concentration inside the ring network box and the preset insulating gas concentration factory inspection value, the scattering attenuation step coefficient inside the ring network box is obtained, which is used to correct the local discharge confidence to obtain the local discharge corrected confidence of each ultrasonic signal frame.

[0059] Furthermore, as the operation time of the insulating gas closed ring network box increases, different degrees of partial discharge occur inside the ring network box, which in turn causes different degrees of decomposition of the insulating gas, producing decomposition products of different components. At this time, when the insulating gas inside the insulating gas closed ring network box is uneven, when the ultrasonic wave of the partial discharge encounters an interface composed of gas media with different acoustic impedances during the propagation process of the partial discharge, the partial discharge ultrasonic wave will produce scattering attenuation, causing the energy of the partial discharge ultrasonic signal received by the ultrasonic sensor to attenuate. There is a high degree of scattering attenuation of the partial discharge ultrasonic signal, resulting in a low confidence level of partial discharge in the ultrasonic signal frame.

[0060] Therefore, this embodiment uses the insulating gas concentration sequence inside the ring network box to reflect the uniformity of the gas medium of the ring network box and the degree of decomposition of the insulating gas by analyzing the short-term change degree of the insulating gas concentration inside the ring network box, evaluates the scattering attenuation degree of the ultrasonic signal in the ring network box, and corrects the partial discharge confidence of the ultrasonic signal frame. In this embodiment, the scattering attenuation compensation coefficient inside the ring network box is obtained by the following formula:

[0061] ; In the formula, is the scattering attenuation compensation coefficient inside the ring network box, is the standard deviation of the insulating gas concentration series inside the ring main box, is the mean value of the insulating gas concentration sequence inside the ring network box, is the factory inspection value of the preset insulating gas concentration inside the ring network box, where the insulating gas concentration inside the ring network box at all collection moments constitutes the insulating concentration sequence inside the ring network box. The larger the value, the worse the uniformity of the gas medium in the ring network box. The larger it is, the higher the degree of decomposition of the insulating gas is, the more interfaces composed of gas media with different acoustic impedances are encountered during the propagation of the local discharge ultrasonic wave, and the higher the degree of scattering attenuation of the local discharge ultrasonic wave, the more compensation should be made, and the larger the corresponding scattering attenuation compensation coefficient is.

[0062] At this point, the scattering attenuation compensation coefficient of the gas medium of the ring network box within the sampling time of the ultrasonic sensor is obtained, and the partial discharge confidence of the ultrasonic signal frame is corrected using the scattering attenuation compensation coefficient to obtain the partial discharge correction confidence. In this embodiment, the normalized value of the product of the partial discharge confidence of each ultrasonic signal frame and the scattering attenuation compensation coefficient is used as the partial discharge correction confidence of each ultrasonic signal frame. The larger the scattering attenuation compensation coefficient, the higher the scattering attenuation caused by the gas medium inside the ring network box to the partial discharge ultrasonic signal, and the more scattering attenuation compensation should be performed to prevent the problem of high scattering attenuation of the partial discharge ultrasonic signal and low partial discharge confidence.

[0063] The third process includes: obtaining the step adjustment index of each ultrasonic signal frame according to the frequency and energy distribution of the spectrum diagram corresponding to each ultrasonic signal frame and the partial discharge correction confidence, determining the adaptive step factor of the ultrasonic signal according to the average level of the step adjustment index of all ultrasonic signal frames in the ultrasonic signal, and using an adaptive filtering algorithm to obtain a pure ultrasonic signal.

[0064] Furthermore, in the process of receiving the partial discharge ultrasonic signal by the ultrasonic sensor, the ultrasonic sensor will also receive some additional echoes due to the reflection of the partial discharge ultrasonic wave propagating through the inner part of the ring network box. The schematic diagram of the propagation path of the additional echo of the ultrasonic sensor is shown in FIG. Figure 3 As shown, Figure 3 In the diagram, number 101 is the ring main box cabinet, number 104 is the ultrasonic sensor, number 102 is the partial discharge inside the ring main box, Figure 3 The solid line in the middle is the propagation path of the partial discharge ultrasonic signal, and the dotted line represents the propagation path of the partial discharge ultrasonic additional echo. These additional echoes are easily identified as partial discharge ultrasonic signals, which seriously interfere with the partial discharge detection results of the ring network box. In the processing of the LMS adaptive filtering algorithm, it is not necessary to retain the detailed characteristics and steady-state effects of the additional echoes. These additional echoes should be given a larger step size factor to improve the convergence speed of the LMS algorithm.

[0065] As an intermittent ultrasonic pulse behavior, the ultrasonic signal energy distribution generated by each local discharge is highly consistent. The additional echo is generated by the reflection of the local discharge ultrasound. Moreover, after a longer propagation path, the high-frequency component ultrasonic signal decays faster than the low-frequency component ultrasonic signal. Therefore, the energy of the high-frequency component of the ultrasonic signal corresponding to the additional echo is significantly reduced.

[0066] Specifically, in this embodiment, for the spectrum diagram of any ultrasonic signal frame, the frequency greater than the preset threshold is regarded as the high frequency, and the frequency corresponding to the bandwidth of the 3dB bandwidth of the peak point has a higher energy. Therefore, in this embodiment, all the high frequencies are traversed in turn, and the high frequencies belonging to the bandwidth corresponding to the 3dB bandwidth of any peak point are recorded as high-energy high frequencies, and the set composed of all high-energy high frequencies is regarded as the high-energy high frequency set of the ultrasonic signal frame. It should be noted that, in this embodiment, the preset threshold is obtained by taking the average value of the two end values ​​of the frequency range in the ultrasonic signal frame spectrum diagram, and the implementer can set it by himself in the actual application scenario.

[0067] Further, the partial discharge correction confidences of all ultrasonic signal frames are arranged from large to small, and the intersection of the high-energy and high-frequency sets of the first preset number of ultrasonic signal frames is obtained as the partial discharge high-energy and high-frequency set. Specifically, in this embodiment, the intersection of the high-energy and high-frequency sets of the first 10 ultrasonic signal frames is selected as the partial discharge high-energy and high-frequency set. The partial discharge high-energy high-frequency set is all high-frequency sets with high energy when partial discharge of the ring network box is suspected to occur.

[0068] Specifically, in this embodiment, the step size adjustment index of the ultrasound signal frame is obtained by the following formula:

[0069] ; In the formula, is the step size adjustment index of the ultrasound signal frame, is the Jaccard distance, is the confidence level of partial discharge correction of the ultrasonic signal frame, To prevent the constant from having a denominator of 0, the value range is 0 to 1. In this embodiment, the value is 0.01. Norm[] is the normalization function. They are respectively the high-energy and high-frequency set of partial discharge and the high-energy and high-frequency set of ultrasonic signal frames. The smaller it is, the lower the possibility that the ultrasonic signal frame contains a local discharge ultrasonic signal. The larger the value is, the higher the degree of energy attenuation of the high-frequency ultrasonic signal in the ultrasonic signal frame is, and the ultrasonic signal frame may contain additional echo signals. In this case, the LMS adaptive filtering algorithm should adopt a larger step size factor to improve the convergence speed of the LMS algorithm and eliminate the influence of noise and additional echo ultrasonic signals on the ring network box status perception.

[0070] In this embodiment, for the ultrasonic signal, the adaptive step size factor of the ultrasonic signal is obtained according to the step size adjustment exponential mean of all ultrasonic signal frames of the ultrasonic signal and the maximum value of the step size factor in the adaptive filtering algorithm. In this embodiment, the specific calculation relationship is:

[0071] ; In the formula, is the adaptive step size factor of the ultrasonic signal, is the maximum value of the step size factor in the adaptive filtering algorithm. In this embodiment, the value is the maximum eigenvalue of the ultrasonic signal autocorrelation matrix. is the step-size adjusted exponential mean of all ultrasound signal frames of the ultrasound signal. The larger the value is, the more noise components and additional echo signals there are in the ultrasonic signal. The LMS algorithm should use a larger step size factor to eliminate the influence of noise components and additional echo signals. The larger the value, the faster the convergence speed of the LMS algorithm. The smaller it is, the more likely it is that the ultrasonic signal contains the local discharge ultrasonic signal of the ring network box, and the smaller the step size factor should be used to retain the detailed features to the maximum extent. The smaller it is, the better the steady-state effect of the LMS algorithm.

[0072] According to the above steps, the ultrasonic signal denoising unit performs denoising processing on the ultrasonic signals received by the two ultrasonic sensors using the LMS algorithm according to the adaptive step size factor, obtains a pure ultrasonic signal, and sends it to the partial discharge identification module via wired transmission.

[0073] Specifically, the flow chart of the ring network box ultrasonic signal denoising in this embodiment is as follows: Figure 4 As shown, to obtain a pure ultrasonic signal.

[0074] The partial discharge identification module is used to obtain the fault type and location of the ring main box based on the pure ultrasonic signal of the ring main box using the partial discharge spectrum.

[0075] The partial discharge identification module is used to realize the fault identification and location of partial discharge in the ring network box. In this embodiment, specifically, the pure ultrasonic signals of two ultrasonic sensors are obtained to generate a PRPD (Phase Resolved Partial Discharge) partial discharge map, and the partial discharge fault identification and location are realized through the PRPD partial discharge map, and the partial discharge fault type of the ring network box and the location of the partial discharge fault in the ring network box are obtained, wherein the generation of the PRPD partial discharge map and the fault identification and location of the partial discharge are all well-known technologies, and the specific process will not be repeated.

[0076] By means of wired transmission, the pure ultrasonic signal of the ring network box, the partial discharge fault type and the location of the partial discharge fault in the ring network box are sent to the wireless communication module, and the partial discharge fault type and the location of the partial discharge fault in the ring network box are sent to the display module.

[0077] The wireless communication module is used to send the fault type and location of the ring network box to the control center through wireless communication technology, and the control center remotely senses the working condition of the ring network box.

[0078] Specifically, the wireless communication module sends the operating status of the ring network box to the control center through wireless communication technology, so that the control center can remotely perceive the working condition of the ring network box and obtain the location of the ring network box through GIS technology. The wireless communication technology can be used to send the location of the ring network box, pure ultrasonic signal, local discharge fault type and the location of the local discharge fault in the ring network box to the control center through 4G, 5G, Wi-Fi, LoRa (Long Range) and NB-IoT (Narrowband Internet of Things).

[0079] The display module is used to receive the fault type and location of the ring network box and visualize the working condition of the ring network box using an LCD liquid crystal display screen.

[0080] The display module receives the partial discharge fault type and the location of the partial discharge fault in the ring main box, and uses an LCD liquid crystal display screen to visualize the working condition of the ring main box.

[0081] It should be noted that the sequence of the above embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0082] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0083] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A ring network box that facilitates remote status perception, characterized in that: The ring network box comprises: Ultrasonic signal acquisition module, used to obtain the ultrasonic signal of the ring network box and the concentration of insulating gas inside the ring network box; The ultrasonic signal analysis module performs frame processing on the ultrasonic signal to obtain each ultrasonic signal frame, analyzes the frequency difference and bandwidth corresponding to the spectrum peak of each ultrasonic signal frame in the frequency domain, so as to obtain the energy distribution concentration degree of each ultrasonic signal frame; based on the amplitude change trend in the neighborhood of the maximum amplitude data point in each ultrasonic signal frame and the amplitude strength of all data points of the ultrasonic signal frame, obtains the waveform feature matching degree of each ultrasonic signal frame, and obtains the partial discharge confidence of each ultrasonic signal frame in combination with the energy distribution concentration degree; According to the discrete degree of the insulating gas concentration inside the ring network box and the difference between the average level of the insulating gas concentration inside the ring network box and the preset insulating gas concentration factory inspection value, the scattering attenuation step coefficient inside the ring network box is obtained to correct the partial discharge confidence to obtain the partial discharge correction confidence of each ultrasonic signal frame; According to the frequency and energy distribution of the spectrum graph corresponding to each ultrasonic signal frame and the confidence of partial discharge correction, the step adjustment index of each ultrasonic signal frame is obtained, the adaptive step factor of the ultrasonic signal is determined according to the average level of the step adjustment index of all ultrasonic signal frames in the ultrasonic signal, and the adaptive filtering algorithm is used to obtain a pure ultrasonic signal; The partial discharge identification module is used to obtain the fault type and location of the ring main box using the partial discharge spectrum according to the pure ultrasonic signal of the ring main box; A wireless communication module is used to send the fault type and location of the ring network box to the control center through wireless communication technology, and the control center remotely senses the working condition of the ring network box; The display module is used to receive the fault type and location of the ring network box and visualize the working condition of the ring network box using an LCD liquid crystal display screen.

2. The ring network box for facilitating remote status perception as claimed in claim 1, characterized in that: The corresponding calculation method for the energy distribution concentration degree of each ultrasonic signal frame is: ; Where E is the energy distribution concentration of the ultrasonic signal frame, are the frequencies corresponding to the sth and s-1th peak points in the spectrum peak sequence of the ultrasonic signal frame, are the frequency bandwidths corresponding to the sth and s-1th peak points in the spectrum peak sequence of the ultrasonic signal frame, respectively. S is the number of peak points in the spectrum graph of the ultrasonic signal frame, wherein all peak points of the spectrum graph of the ultrasonic signal frame are arranged in ascending order of frequency to form the spectrum peak sequence of the ultrasonic signal frame.

3. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The corresponding calculation method of the waveform feature matching degree of each ultrasonic signal frame is: ; In the formula, is the waveform feature matching degree of the ultrasonic signal frame, is the cumulative sum of the square values ​​of the amplitudes of all data points in the ultrasonic signal frame, is an exponential function with a natural constant as base, It is the trend statistic of the amplitude sequence of the ultrasonic signal frame, wherein the amplitude sequence is constructed according to the amplitudes of all data points in the neighborhood of the data point where the maximum amplitude of the ultrasonic signal frame is located, and the trend statistic of the amplitude sequence is obtained by a trend test algorithm.

4. The ring network box for facilitating remote status perception as claimed in claim 3, characterized in that: The construction of the amplitude sequence includes: Taking the data point with the largest amplitude in the ultrasonic signal frame as the starting point, all data points within a preset time length are selected to the right, and the amplitudes of all selected data points are arranged in ascending order of time of the data points to form an amplitude sequence.

5. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The partial discharge confidence of each ultrasonic signal frame is the product of the energy distribution concentration degree of each ultrasonic signal frame and the waveform feature matching degree.

6. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The corresponding calculation method of the scattering attenuation step coefficient inside the ring network box is: ; In the formula, is the scattering attenuation compensation coefficient inside the ring network box, is the standard deviation of the insulating gas concentration series inside the ring main box, is the mean value of the insulating gas concentration sequence inside the ring network box, The factory inspection value of the insulating gas concentration inside the ring network box is preset, wherein the insulating gas concentration inside the ring network box at all acquisition moments constitutes the insulating concentration sequence inside the ring network box.

7. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The partial discharge correction confidence of each ultrasonic signal frame is a normalized value of the product of the partial discharge confidence of each ultrasonic signal frame and the scattering attenuation compensation coefficient.

8. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The step size adjustment index of each ultrasonic signal frame is calculated as follows: ; In the formula, is the step size adjustment index of the ultrasound signal frame, is the Jaccard distance, is the confidence level of partial discharge correction of the ultrasonic signal frame, To prevent the denominator from being a constant of 0, Norm[] is a normalization function. They are respectively the high-energy and high-frequency set of partial discharge and the high-energy and high-frequency set of ultrasonic signal frames.

9. The ring network box for facilitating remote status perception as claimed in claim 8, characterized in that: The method for acquiring the local discharge high-energy and high-frequency set and the high-energy and high-frequency set of the ultrasonic signal frame further comprises: The frequencies in the spectrum of the ultrasonic signal frame that are greater than a preset threshold are regarded as high frequencies, and the high frequencies that belong to the frequency bandwidth corresponding to the 3dB bandwidth of any peak point are recorded as high-energy high frequencies, and all high-energy high frequencies are composed of a high-energy high frequency set of the ultrasonic signal frame; The partial discharge correction confidences of all ultrasonic signal frames are arranged in descending order, and the intersection of the high-energy and high-frequency sets of the first preset number of ultrasonic signal frames is used as the partial discharge high-energy and high-frequency set.

10. The ring network box for facilitating remote status perception according to claim 1, characterized in that: The corresponding calculation method of the adaptive step size factor of the ultrasonic signal is: ; In the formula, is the adaptive step size factor of the ultrasonic signal, is the step-size adjusted exponential mean of all ultrasound signal frames of the ultrasound signal, is the maximum value of the step size factor in the adaptive filtering algorithm, and its value is the maximum eigenvalue of the autocorrelation matrix of the ultrasonic signal.

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