Power line noise suppression method based on carrier spectrum analysis

Abstract

The invention relates to the technical field of power line data communication, in particular to a power line noise suppression method based on carrier spectrum analysis, and the method comprises the steps: calculating a noise distribution complexity tendency value around a power line based on the complexity of power line distribution and the type number of load equipment connected to the power line; determining an acquisition mode of a power line carrier signal based on the noise distribution complex type around the power line; determining the position of a noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal of the key node of the power line in the preprocessed observation period; the noise type is determined based on the noise intensity of the noise source position and the consistency degree of the noise occurrence time and the load dynamic change time; and determining whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value. According to the invention, the noise suppression effect is improved by improving the accuracy of noise type judgment.

Description

Technical Field

[0001] The present invention relates to the technical field of power line data communication, and in particular to a power line noise suppression method based on carrier spectrum analysis. Background Art

[0002] In today's power system, intelligent monitoring and control of low-voltage equipment plays a vital role. With the continuous development of smart grids, various smart devices such as smart meters, smart circuit breakers, photovoltaic inverters, street lights, and charging piles have been widely used in low-voltage areas. These devices require efficient and reliable communication means to achieve data transmission and remote control to meet the requirements of smart grids for intelligent and automated management of power systems. However, power lines as communication media are not ideal communication environments, and there are various complex noise interferences. Traditional filtering methods use low-pass, high-pass or band-pass filters to filter out specific frequency components in power line noise. However, the spectrum of power line noise is very complex and time-varying, and the fixed frequency response of traditional filters is difficult to adapt to changes in the noise spectrum.

[0003] Chinese patent application publication number: CN116545476A discloses a method for suppressing pulse noise in a power line carrier communication system, which belongs to the field of power line data communication. The method includes: S1: parameter adaptation: inputting the received signal into the parameter adaptation module at the receiving end, and adapting the condition parameters, i.e., detection parameters and noise suppression parameters, for the pulse noise detection module and the pulse noise suppression module by means of a sliding window; S2: pulse noise detection: inputting the received data into the pulse noise detection module in blocks, obtaining the peak value of the detection data block, and comparing the peak value with the adapted detection parameter to determine whether there is pulse noise; S3: pulse noise suppression: continuously finding the maximum value and position of each segment of received data and setting the maximum value and the data in its adjacent interval to zero, and finally limiting the data above a certain threshold to suppress pulse noise. The invention method is simple to implement and does not require experience to select the amplitude threshold.

[0004] It can be seen that the existing technology has the problem that the power line carrier signal is not accurately collected, resulting in inaccurate judgment of the noise source location and inaccurate judgment of the noise type, resulting in poor noise suppression effect. Summary of the invention

[0005] To this end, the present invention provides a power line noise suppression method based on carrier spectrum analysis to overcome the problems in the prior art of inaccurate power line carrier signal acquisition leading to inaccurate noise source location judgment and inaccurate noise type judgment resulting in poor noise suppression effect.

[0006] To achieve the above object, the present invention provides a method for suppressing power line noise based on carrier spectrum analysis, comprising: Using a sensor to collect a power line carrier signal, and calculating a noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the number of types of load devices connected to the power line; Determine a method for collecting power line carrier signals based on the complexity type of noise distribution around the power line, wherein the complexity type of noise distribution around the power line is determined according to a comparison result between a complexity tendency value of the noise distribution around the power line and a preset complexity tendency value of noise distribution; Preprocessing the collected power line carrier signal, and determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal at the key nodes of the power line within the observation period after preprocessing, wherein the key nodes of the power line are determined according to the power line branch point and the noise generation frequency of the load equipment connected to the power line within a preset time; Determine the noise type based on the noise intensity at the noise source location and the consistency between the time when the noise occurs and the time when the load changes dynamically, wherein the noise type includes suppressed noise, irrelevant noise, and noise to be analyzed; Based on the power line communication quality evaluation value, it is determined whether to adjust the power line noise suppression process parameters, wherein the power line communication quality evaluation value is determined according to the bit error rate and signal-to-noise ratio of the power line communication, and the power line noise suppression process parameters include a preset noise distribution complexity tendency value, a preset noise intensity, and a preset generation frequency.

[0007] Further, the calculating of the noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the number of types of load devices connected to the power line includes: The complexity of the power line distribution is determined according to the sum of the ratio of the line length of the power line to the maximum line length of the power line during the historical noise suppression process and the ratio of the number of branches of the power line to the maximum number of branches of the power line during the historical noise suppression process; The noise distribution complexity tendency value around the power line is determined according to the sum of the ratios of the complexity of the power line distribution to the number of types of load devices connected to the power line and the maximum number of types of load devices connected to the power line during historical noise suppression.

[0008] Furthermore, the method of determining the acquisition method of the power line carrier signal based on the complex type of noise distribution around the power line includes: If the noise distribution complexity type around the power line is a complex type, determine to collect the power line carrier signal in a multi-sensor collaborative collection manner; If the noise distribution complexity type around the power line is a simple type, it is determined that the power line carrier signal is collected in a single sensor fixed-point collection mode.

[0009] Further, the noise distribution complexity type around the power line is determined according to a comparison result of the noise distribution complexity tendency value around the power line and a preset noise distribution complexity tendency value, including: If the noise distribution complexity tendency value around the power line is less than or equal to the preset noise distribution complexity tendency value, determining that the noise distribution complexity type around the power line is a simple type; If the complexity tendency value of the noise distribution around the power line is greater than the preset complexity tendency value of the noise distribution, it is determined that the complexity type of the noise distribution around the power line is a complex type.

[0010] Furthermore, the step of determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal at the key node of the power line within the observation period after preprocessing includes: The observation period is divided into a complete period from the operation to the stop of the load equipment connected to the power line; Obtaining the fluctuation range of the energy spectrum density of the carrier signal of the key node of the power line within the observation period after preprocessing; Comparing the fluctuation range of the energy spectrum density with a preset fluctuation range to determine whether the energy spectrum density is an abnormal fluctuation; The location of the noise source is determined based on the upstream and downstream key nodes where abnormal fluctuations in energy spectral density occur.

[0011] Furthermore, the key nodes of the power line are determined according to the power line branch points and the noise generation frequencies of the load devices connected to the power lines, including: The power line branch points and the access points and outflow points of load devices whose noise generation frequency is greater than the preset generation frequency within the preset time are used as key nodes.

[0012] Further, the determining of the noise type based on the noise intensity at the noise source position and the consistency between the time when the noise occurs and the time when the load changes dynamically includes: If the noise intensity is greater than the preset noise intensity and the consistency between the time when the noise occurs and the time when the load changes dynamically is less than the preset consistency, the noise type is determined to be irrelevant noise; If the noise intensity is greater than the preset noise intensity and the consistency between the time when the noise occurs and the time when the load changes dynamically is greater than or equal to the preset consistency, the noise type is determined to be suppressed noise; If the noise intensity is less than or equal to the preset noise intensity, it is determined that the noise type is noise to be analyzed.

[0013] Furthermore, the preset noise intensity is determined according to a historical average value of noise intensity at the noise source position when the power line is in a normal operating state.

[0014] Further, the determining whether to adjust the parameters of the power line noise suppression process based on the power line communication quality evaluation value includes: If the power line communication quality evaluation value is greater than a preset evaluation value, it is determined to adjust the parameters of the power line noise suppression process.

[0015] Furthermore, the adjustment amount of the preset noise distribution complexity tendency value is negatively correlated with the power line communication quality evaluation value, the adjustment amount of the preset noise intensity is negatively correlated with the power line communication quality evaluation value, and the adjustment amount of the preset generation frequency is positively correlated with the power line communication quality evaluation value.

[0016] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention calculates the complexity by considering the distribution characteristics of the power line itself (line length and number of branches), and then determines the noise distribution complexity tendency value in combination with the number of load device types. This method can be evaluated according to the specific conditions of each power line. With the development of the power system and the upgrading of equipment, the layout of the power lines and the types of load devices will change, and this calculation method can adapt well to these changes. Each time the noise suppression process is performed, new data (such as the updated maximum line length, maximum number of branches and maximum number of load device types) can be recorded for the next complex tendency value calculation. The signal acquisition method (single sensor fixed-point acquisition or multi-sensor collaborative acquisition) is determined based on the comparison result of the calculated noise distribution complex tendency value with the preset value. This decision-making method based on quantitative evaluation can make signal acquisition more reasonable and efficient. In the subsequent noise source positioning step, accurate noise distribution complex tendency value calculation helps to more specifically determine the key nodes of the power line, because the distribution and importance of key nodes of power lines with different complexities are also different. In a complex power line system, more branch points and different types of load device access points may be key nodes; while in a simple power line system, key nodes are relatively few and easier to determine. In this way, the abnormal fluctuations of the carrier signal energy spectrum density of the key nodes within the observation period after preprocessing can be used more efficiently to locate the noise source, thereby improving the accuracy of noise type judgment to enhance the noise suppression effect.

[0017] Furthermore, the present invention can accurately determine the type of noise distribution complexity by evaluating the complexity tendency value of the noise distribution around the power line and comparing it with the preset value, so as to select the most suitable power line carrier signal acquisition method. In the case of simple noise distribution, a single sensor is used for fixed-point acquisition, which avoids the unnecessary cost and data processing workload caused by the use of multiple sensors, and improves the acquisition efficiency. This method can quickly determine the use of a single sensor for fixed-point acquisition, which not only meets the signal acquisition requirements, but also saves resources and time. For a power line environment with complex noise distribution, a multi-sensor collaborative acquisition method can give full play to the advantages of each sensor and comprehensively collect power line carrier signals from different positions and angles, so that the signal characteristics in a complex noise environment can be captured more accurately, avoiding possible omissions or misjudgments of a single sensor. In a simple type of noise environment, the noise source is relatively small and easy to analyze, and the noise type can be determined more quickly and the corresponding suppression method can be adopted. In a complex type of noise environment, the data collected by multiple sensors in a collaborative manner can more comprehensively understand the distribution and characteristics of the noise, and provide more information for accurately determining the noise type. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect.

[0018] Furthermore, the present invention determines the noise type by combining multiple factors such as noise intensity, the consistency between the occurrence time and the load dynamic change time, and can achieve accurate classification of noise. This allows the most suitable suppression method or analysis strategy to be adopted for different types of noise in subsequent processing. For the noise to be analyzed, by recording in detail the changes in the operating status of the load equipment when it occurs, potential noise problems can be discovered in time. If it is found that the noise is correlated with the operation time of a specific device, it is classified as irrelevant noise to avoid over-analysis; if there is no correlation, it is classified as suppressed noise, and further analysis of its specific type helps to prevent possible communication failures in advance and ensure the reliable operation of the power line communication system. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect.

[0019] Furthermore, the present invention determines whether to adjust the noise suppression process parameters by comparing the power line communication quality evaluation value with the preset evaluation value, so that the system can automatically adjust according to the actual communication quality situation, thereby realizing adaptive noise suppression. When it is determined that the noise suppression process parameters need to be adjusted, the preset noise distribution complexity tendency value, the preset noise intensity and the preset generation frequency are adjusted with different adjustment coefficients respectively. This targeted adjustment method can suppress noise more effectively. By continuously monitoring and adjusting the noise suppression process parameters, the power line communication quality can be continuously optimized. As the system runs, the characteristics of the noise may change. By adjusting the parameters in time, it can be ensured that the noise suppression measures always maintain the best effect. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The following is a flowchart of a method for suppressing power line noise based on carrier spectrum analysis according to an embodiment of the present invention; Figure 2 A flowchart of determining the complex type of noise distribution around a power line in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention; Figure 3 A flowchart of determining whether to adjust noise suppression process parameters in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention; Figure 4 The present invention is a flowchart of a process for determining the location of a noise source in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0023] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0024] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] See also Figure 1-Figure 4 As shown, Figure 1 The following is a flowchart of a method for suppressing power line noise based on carrier spectrum analysis according to an embodiment of the present invention; Figure 2 A flowchart of determining the complex type of noise distribution around a power line in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention; Figure 3 A flowchart of determining whether to adjust noise suppression process parameters in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention; Figure 4 The present invention is a flowchart of a process for determining the location of a noise source in a power line noise suppression method based on carrier spectrum analysis according to an embodiment of the present invention.

[0026] The power line noise suppression method based on carrier spectrum analysis in an embodiment of the present invention includes: Step S1, using a sensor to collect a power line carrier signal, and calculating a noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the number of types of load devices connected to the power line; Step S2, determining a method for collecting a power line carrier signal based on a complexity type of noise distribution around the power line, wherein the complexity type of noise distribution around the power line is determined according to a comparison result of a complexity tendency value of the noise distribution around the power line and a preset complexity tendency value of noise distribution; Step S3, preprocessing the collected power line carrier signal, and determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal of the key node of the power line within the observation period after the preprocessing, wherein the key node of the power line is determined according to the noise generation frequency of the power line branch point and the load device connected to the power line within a preset time; Step S4, determining the noise type based on the noise intensity at the noise source location and the consistency between the time when the noise occurs and the time when the load changes dynamically, wherein the noise type includes suppressed noise, irrelevant noise, and noise to be analyzed; Step S5, determining whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value, wherein the power line communication quality evaluation value is determined according to the bit error rate and signal-to-noise ratio of the power line communication, and the power line noise suppression process parameters include a preset noise distribution complexity tendency value, a preset noise intensity, and a preset generation frequency.

[0027] The sensors in the embodiment of the present invention include but are not limited to "current transformers, voltage transformers and capacitive couplers", and the pre-processing of the collected power line carrier signal includes but is not limited to "filtering processing, noise reduction processing and amplification processing".

[0028] Specifically, in step S1, the noise distribution complexity tendency value around the power line is calculated based on the complexity of the power line distribution and the number of types of load devices connected to the power line; The complexity of the power line distribution is determined according to the sum of the ratio of the line length of the power line to the maximum line length of the power line during the historical noise suppression process and the ratio of the number of branches of the power line to the maximum number of branches of the power line during the historical noise suppression process; The noise distribution complexity tendency value around the power line is determined according to the sum of the ratios of the complexity of the power line distribution to the number of types of load devices connected to the power line and the maximum number of types of load devices connected to the power line during historical noise suppression.

[0029] The present invention calculates the complexity by considering the distribution characteristics of the power line itself (line length and number of branches), and then determines the noise distribution complexity tendency value in combination with the number of load device types. This method can be evaluated based on the specific conditions of each power line. With the development of the power system and the upgrading of equipment, the layout of the power lines and the types of load devices will change. This calculation method can adapt well to these changes. Each time the noise suppression process is performed, new data (such as the updated maximum line length, maximum number of branches and maximum number of load device types) can be recorded for the next complex tendency value calculation. The signal acquisition method (single sensor fixed-point acquisition or multi-sensor collaborative acquisition) is determined based on the comparison result of the calculated noise distribution complex tendency value with the preset value. This decision-making method based on quantitative evaluation can make signal acquisition more reasonable and efficient. In the subsequent noise source positioning step, accurate noise distribution complex tendency value calculation helps to more specifically determine the key nodes of the power line, because the distribution and importance of key nodes of power lines with different complexities are also different. In a complex power line system, more branch points and different types of load device access points may be key nodes; while in a simple power line system, key nodes are relatively few and easier to determine. In this way, the abnormal fluctuations of the carrier signal energy spectrum density of the key nodes within the observation period after preprocessing can be used more efficiently to locate the noise source, thereby improving the accuracy of noise type judgment to enhance the noise suppression effect.

[0030] Specifically, in step S2, when determining the acquisition method of the power line carrier signal, the acquisition method of the power line carrier signal is determined according to the complexity type of the noise distribution around the power line; When the noise distribution complexity type around the power line is a complex type, determining to collect the power line carrier signal in a multi-sensor collaborative collection manner; When the noise distribution complexity type around the power line is a simple type, it is determined to collect the power line carrier signal in a single sensor fixed-point collection mode.

[0031] In the embodiment of the present invention, the method of collecting power line carrier signals in a single-sensor fixed-point collection manner includes placing a sensor at a specific position of the power line to collect the carrier signal. The position is usually a key position determined based on experience or a preliminary analysis of the power line system, such as an access point, a main branch point, or a position close to an important load device of the power line. The sensor will continuously monitor the power line carrier signal at this point and record the time domain or frequency domain information of the signal (such as voltage, current changes, frequency components, etc.); the method of collecting the power line carrier signal in a multi-sensor collaborative collection manner includes placing sensors at multiple different positions of the power line. The selection of these positions is based on a detailed analysis of the power line system, including the topological structure of the power line (branching conditions, line length, etc.), the distribution and type of connected load devices, and other factors. The sensors cooperate with each other to collect power line carrier signals from different angles. For example, sensors are installed at each branch node of the power line and the access and outflow points of different types of load devices.

[0032] Specifically, in step S2, when determining the noise distribution complexity type around the power line, the noise distribution complexity type around the power line is determined according to a comparison result between the noise distribution complexity tendency value around the power line and a preset noise distribution complexity tendency value; When the noise distribution complexity tendency value around the power line is less than or equal to the preset noise distribution complexity tendency value, determining that the noise distribution complexity type around the power line is a simple type; When the noise distribution complexity tendency value around the power line is greater than the preset noise distribution complexity tendency value, it is determined that the noise distribution complexity type around the power line is a complex type.

[0033] The preset noise distribution complexity tendency value in the embodiment of the present invention is based on the average value of the power line noise distribution complexity tendency value in the historical noise suppression process, but the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0034] The present invention can accurately determine the complex type of noise distribution by evaluating the complex tendency value of noise distribution around the power line and comparing it with the preset value, so as to select the most suitable power line carrier signal acquisition method. In the case of simple noise distribution, a single sensor is used for fixed-point acquisition, which avoids the unnecessary cost and data processing workload caused by using multiple sensors, and improves the acquisition efficiency. Through this method, it can be quickly determined that a single sensor is used for fixed-point acquisition, which not only meets the signal acquisition requirements, but also saves resources and time. For a power line environment with complex noise distribution, a multi-sensor collaborative acquisition method can give full play to the advantages of each sensor and comprehensively collect power line carrier signals from different positions and angles, so that the signal characteristics in a complex noise environment can be captured more accurately, avoiding the omission or misjudgment that may occur in a single sensor. In a simple type of noise environment, the noise source is relatively small and easy to analyze, and the noise type can be determined more quickly and the corresponding suppression method can be adopted. In a complex type of noise environment, through the data collected by multiple sensors in a collaborative manner, the distribution and characteristics of the noise can be more comprehensively understood, and more information is provided for accurately determining the noise type. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect.

[0035] Specifically, in step S3, the step of determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal at the key node of the power line within the observation period after preprocessing includes: Step S3301, dividing the observation period into a complete period from the operation to the stop of the load device connected to the power line; Step S3302, obtaining the fluctuation range of the energy spectrum density of the carrier signal of the key node of the power line within the observation period after preprocessing; Step S3303, comparing the fluctuation range of the energy spectrum density with a preset fluctuation range to determine whether the energy spectrum density is abnormally fluctuating; Step S3304: determine the location of the noise source based on the upstream and downstream key nodes where the abnormal fluctuation of energy spectrum density occurs.

[0036] In the embodiment of the present invention, determining the location of the noise source based on the upstream and downstream key nodes where the abnormal fluctuation of the energy spectrum density occurs includes locating the noise source by comparing the positional relationship between the key node where the abnormal fluctuation of the energy spectrum density occurs and its upstream and downstream nodes in the power line branch structure. For example, if there is no abnormal fluctuation at the upstream key node of a branch, but an abnormal fluctuation occurs at the downstream key node, then the noise source is located on the load device connected to the branch line between the two nodes.

[0037] The value of the preset fluctuation range in the embodiment of the present invention is set to -5% to 5%, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0038] Specifically, in step S3, the power line key node determines the power line branch point and the access point and outflow point of the load device whose noise generation frequency is greater than the preset generation frequency as the key node according to the power line branch point and the noise generation frequency of the load device connected to the power line.

[0039] In the embodiment of the present invention, the preset time is set to 8 times of a complete cycle from the operation of the load device connected to the power line to the stop, and the preset generation frequency is the average value of the noise generation frequency of the load device connected to the power line within the preset time, but the above value is not limited to this, and technical personnel in this field can also adjust the value according to actual needs.

[0040] Specifically, in step S4, when determining the noise type, the noise type is determined according to the noise intensity at the noise source location and the consistency between the time when the noise occurs and the time when the load changes dynamically; When the noise intensity is greater than the preset noise intensity and the consistency between the time when the noise occurs and the time when the load changes dynamically is less than the preset consistency, the noise type is determined to be irrelevant noise; When the noise intensity is greater than the preset noise intensity and the consistency between the time when the sound occurs and the time when the load changes dynamically is greater than or equal to the preset consistency, the noise type is determined to be suppressed noise; When the noise intensity is less than or equal to the preset noise intensity, the noise type is determined to be noise to be analyzed.

[0041] In the embodiment of the present invention, the degree of consistency between the time when the noise occurs and the time when the load changes dynamically is the sum of the absolute value of the difference between the start time of the noise occurrence and the time when the load changes dynamically and the absolute value of the difference between the time when the noise disappears and the time when the load changes dynamically. The preset noise intensity is the historical average value of the noise intensity at the position of the noise source under normal operating conditions of the power line. The preset degree of consistency is the historical average value of the degree of consistency between the noise occurrence time and the load dynamic change time when there is no noise interference or a stable noise source. The load dynamic change time is the moment when the operating state of the load device connected to the power line changes, but the above values ​​are not limited to this, and technicians in this field can also adjust the values ​​according to actual needs.

[0042] In the embodiment of the present invention, when the noise type is suppressed noise, it is determined to further analyze the specific type of noise and then select the corresponding suppression method. For example, the noise spectrum is analyzed by a spectrum analyzer. The narrowband noise is manifested in the spectrum as obvious energy concentration in a narrow frequency range. For example, by observing the spectrum graph, if it is found that the energy in a frequency band with a bandwidth of several hundred Hz is significantly higher than that in other frequency bands near a certain center frequency, it may be narrowband noise. At this time, a notch filter for the center frequency is designed and installed at the front end of the power line communication device; when the noise type is noise to be analyzed, the operating state change of the load device is recorded in detail each time the noise occurs. For example, it is observed whether the noise occurs regularly when a certain device is started, stopped or switched to a working mode. If it is found that the noise occurrence time is correlated with the operation time of the specific device, the noise is classified as irrelevant noise. If it is found that the noise occurrence time is not correlated with the operation time of the specific device, the noise is classified as suppressed noise.

[0043] The present invention determines the noise type by combining multiple factors such as noise intensity, the consistency between the occurrence time and the dynamic change time of the load, and can achieve accurate classification of noise. This allows the most suitable suppression method or analysis strategy to be adopted for different types of noise in subsequent processing. For the noise to be analyzed, by recording in detail the changes in the operating state of the load equipment when it occurs, potential noise problems can be discovered in time. If it is found that the noise is correlated with the operating time of a specific device, it is classified as irrelevant noise to avoid over-analysis of it; if there is no correlation, it is classified as suppressed noise, and further analysis of its specific type helps to prevent possible communication failures in advance and ensure the reliable operation of the power line communication system. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect.

[0044] Specifically, when determining whether to adjust the parameters of the power line noise suppression process, determining whether to adjust the parameters of the power line noise suppression process is based on a comparison result of the power line communication quality evaluation value and a preset evaluation value; When the power line communication quality evaluation value is greater than a preset evaluation value, determining that a power line noise suppression process parameter needs to be adjusted; When the power line communication quality evaluation value is less than or equal to the preset evaluation value, it is determined that there is no need to adjust the parameters of the power line noise suppression process.

[0045] The power line communication quality assessment value in the embodiment of the present invention is half of the sum of the bit error rate and the inverse of the signal-to-noise ratio, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0046] Specifically, in step S5, when it is determined that the power line noise suppression process parameters need to be adjusted, the preset noise distribution complexity tendency value is adjusted by a first adjustment coefficient, the preset noise intensity is adjusted by a second adjustment coefficient, and the preset generation frequency is adjusted by a third adjustment coefficient.

[0047] In the embodiment of the present invention, the value range of the first adjustment coefficient is set to 0.81-0.95, the value range of the second adjustment coefficient is set to 0.83-0.97, and the value range of the third adjustment coefficient is set to 1.05-1.21, but the above values ​​are not limited to this. Those skilled in the art may also adjust the values ​​according to actual needs. The adjustment amount of the preset noise distribution complexity tendency value is negatively correlated with the power line communication quality evaluation value, the adjustment amount of the preset noise intensity is negatively correlated with the power line communication quality evaluation value, and the adjustment amount of the preset generation frequency is positively correlated with the power line communication quality evaluation value.

[0048] The present invention determines whether to adjust the noise suppression process parameters by comparing the power line communication quality evaluation value with the preset evaluation value, so that the system can automatically adjust according to the actual communication quality situation, thereby realizing adaptive noise suppression. When it is determined that the noise suppression process parameters need to be adjusted, the preset noise distribution complexity tendency value, the preset noise intensity and the preset generation frequency are adjusted with different adjustment coefficients respectively. This targeted adjustment method can suppress noise more effectively. By continuously monitoring and adjusting the noise suppression process parameters, the power line communication quality can be continuously optimized. As the system runs, the characteristics of the noise may change. By adjusting the parameters in time, it can be ensured that the noise suppression measures always maintain the best effect. The above method improves the accuracy of noise type judgment and thus improves the noise suppression effect.

[0049] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for suppressing power line noise based on carrier spectrum analysis, characterized in that: include: Using a sensor to collect a power line carrier signal, and calculating a noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the number of types of load devices connected to the power line; Determine a method for collecting power line carrier signals based on the complexity type of noise distribution around the power line, wherein the complexity type of noise distribution around the power line is determined according to a comparison result between a complexity tendency value of the noise distribution around the power line and a preset complexity tendency value of noise distribution; Preprocessing the collected power line carrier signal, and determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal at the key nodes of the power line within the observation period after preprocessing, wherein the key nodes of the power line are determined according to the power line branch point and the noise generation frequency of the load equipment connected to the power line within a preset time; Determine the noise type based on the noise intensity at the noise source location and the consistency between the time when the noise occurs and the time when the load changes dynamically, wherein the noise type includes suppressed noise, irrelevant noise, and noise to be analyzed; Based on the power line communication quality evaluation value, it is determined whether to adjust the power line noise suppression process parameters, wherein the power line communication quality evaluation value is determined according to the bit error rate and signal-to-noise ratio of the power line communication, and the power line noise suppression process parameters include a preset noise distribution complexity tendency value, a preset noise intensity, and a preset generation frequency.

2. The method for suppressing power line noise based on carrier spectrum analysis according to claim 1, characterized in that: The calculating of the noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the number of types of load devices connected to the power line includes: The complexity of the power line distribution is determined according to the sum of the ratio of the line length of the power line to the maximum line length of the power line during the historical noise suppression process and the ratio of the number of branches of the power line to the maximum number of branches of the power line during the historical noise suppression process; The noise distribution complexity tendency value around the power line is determined according to the sum of the ratios of the complexity of the power line distribution to the number of types of load devices connected to the power line and the maximum number of types of load devices connected to the power line during historical noise suppression.

3. The method for suppressing power line noise based on carrier spectrum analysis according to claim 2, characterized in that: The method of determining the acquisition method of the power line carrier signal based on the complex type of noise distribution around the power line includes: If the noise distribution complexity type around the power line is a complex type, determine to collect the power line carrier signal in a multi-sensor collaborative collection manner; If the noise distribution around the power line is of a simple type, it is determined that the power line carrier signal is collected in a single sensor fixed-point collection mode.

4. The method for suppressing power line noise based on carrier spectrum analysis according to claim 3, characterized in that: The noise distribution complexity type around the power line is determined according to a comparison result between the noise distribution complexity tendency value around the power line and a preset noise distribution complexity tendency value, including: If the noise distribution complexity tendency value around the power line is less than or equal to the preset noise distribution complexity tendency value, determining that the noise distribution complexity type around the power line is a simple type; If the complexity tendency value of the noise distribution around the power line is greater than the preset complexity tendency value of the noise distribution, it is determined that the complexity type of the noise distribution around the power line is a complex type.

5. The method for suppressing power line noise based on carrier spectrum analysis according to claim 4, characterized in that: The step of determining the location of the noise source based on the abnormal fluctuation of the energy spectrum density of the carrier signal of the key node of the power line within the observation period after preprocessing comprises: The observation period is divided into a complete period from the operation to the stop of the load equipment connected to the power line; Obtaining the fluctuation range of the energy spectrum density of the carrier signal of the key node of the power line within the observation period after preprocessing; Comparing the fluctuation range of the energy spectrum density with a preset fluctuation range to determine whether the energy spectrum density is an abnormal fluctuation; The location of the noise source is determined based on the upstream and downstream key nodes where abnormal fluctuations in energy spectral density occur.

6. The method for suppressing power line noise based on carrier spectrum analysis according to claim 5, characterized in that: The key nodes of the power line are determined according to the branch points of the power line and the noise generation frequency of the load devices connected to the power line, including: The power line branch points and the access points and outflow points of load devices whose noise generation frequency is greater than the preset generation frequency within the preset time are used as key nodes.

7. The method for suppressing power line noise based on carrier spectrum analysis according to claim 6, characterized in that: The determining of the noise type based on the noise intensity at the noise source location and the consistency between the time when the noise occurs and the time when the load changes dynamically includes: If the noise intensity is greater than the preset noise intensity and the consistency between the time when the noise occurs and the time when the load changes dynamically is less than the preset consistency, the noise type is determined to be irrelevant noise; If the noise intensity is greater than the preset noise intensity and the consistency between the time when the noise occurs and the time when the load changes dynamically is greater than or equal to the preset consistency, the noise type is determined to be suppressed noise; If the noise intensity is less than or equal to the preset noise intensity, it is determined that the noise type is noise to be analyzed.

8. The method for suppressing power line noise based on carrier spectrum analysis according to claim 7, characterized in that: The preset noise intensity is determined according to a historical average value of the noise intensity at the noise source position when the power line is in a normal operating state.

9. The method for suppressing power line noise based on carrier spectrum analysis according to claim 8, characterized in that: The determining whether to adjust the parameters of the power line noise suppression process based on the power line communication quality evaluation value comprises: If the power line communication quality evaluation value is greater than a preset evaluation value, it is determined to adjust the parameters of the power line noise suppression process.

10. The method for suppressing power line noise based on carrier spectrum analysis according to claim 9, characterized in that: The adjustment amount of the preset noise distribution complexity tendency value is negatively correlated with the power line communication quality evaluation value, the adjustment amount of the preset noise intensity is negatively correlated with the power line communication quality evaluation value, and the adjustment amount of the preset generation frequency is positively correlated with the power line communication quality evaluation value.

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