A method for analyzing power line noise based on carrier frequency spectrum analysis

Abstract

The present invention relates to the technical field of power line data communication, and in particular to a power line noise analysis method based on carrier frequency spectrum analysis. The method includes calculating a noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the type and quantity of load devices connected to the power line; determining the acquisition method of the power line carrier signal based on the complexity type of the noise distribution around the power line; determining the noise source location based on the abnormal fluctuation of the energy spectral density of the carrier signal at key nodes of the power line within the observation period after preprocessing; determining the noise type based on the noise intensity at the noise source location and the consistency degree between the time when the noise appears and the time of the dynamic change of the load; determining whether to adjust the process parameters of the power line noise suppression based on the power line communication quality evaluation value. The present invention improves the noise suppression effect 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 particularly to a power line noise analysis method based on carrier spectrum analysis. Background Art

[0002] In today's power system, the intelligent monitoring and control of equipment in low-voltage substations play a crucial role. With the continuous development of smart grids, various intelligent devices such as smart meters, smart circuit breakers, photovoltaic inverters, street lights, and charging piles have been widely used in low-voltage substations. These devices require efficient and reliable communication means to achieve data transmission and remote control to meet the requirements of the smart grid for the intelligent and automated management of the power system. However, the power line as a communication medium is not an ideal communication environment, 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 the 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 the changes in the noise spectrum. Chinese Patent Application Publication No.: CN116545476A discloses a method for suppressing impulse noise in a power line carrier communication system, belonging to the field of power line data communication. The method includes: S1: Parameter adaptation: At the receiving end, the received signal is input into the parameter adaptation module, and the condition parameters, that is, the detection parameters and the noise suppression parameters, are adapted for the impulse noise detection module and the impulse noise suppression module in a sliding window manner; S2: Impulse noise detection: The received data is input into the impulse noise detection module in blocks, the peak value of the detected data block is obtained, and the peak value is compared with the adapted detection parameters to determine whether there is impulse noise; S3: Impulse noise suppression: By means of iteration, the maximum value and its position of each segment of the received data are continuously found, and the data within the maximum value and its adjacent intervals are set to zero, and finally the data higher than a certain threshold is limited to achieve the effect of suppressing impulse noise. The method of the present invention is simple to implement and does not require relying on experience to select the amplitude threshold.

[0003] It can be seen that the existing technology has problems such as inaccurate acquisition of power line carrier signals, resulting in inaccurate judgment of the noise source position and inaccurate judgment of the noise type, resulting in poor noise suppression effect. Summary of the Invention

[0004] Therefore, the present invention provides a power line noise analysis method based on carrier spectrum analysis to overcome the problems in the existing technology that inaccurate acquisition of power line carrier signals leads to inaccurate judgment of the noise source position and inaccurate judgment of the noise type, resulting in poor noise suppression effect.

[0005] To achieve the above object, the present invention provides a power line noise analysis method based on carrier spectrum analysis, including:

[0006] Collect power line carrier signals using sensors, and calculate the complex tendency value of the noise distribution 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;

[0007] Determine the acquisition method of the power line carrier signal based on the complex type of the noise distribution around the power line, where the complex type of the noise distribution around the power line is determined according to the comparison result between the complex tendency value of the noise distribution around the power line and the preset complex tendency value of the noise distribution;

[0008] Preprocess the collected power line carrier signals, and determine the noise source location based on the abnormal fluctuations of the energy spectral density of the carrier signals at the key nodes of the power line during the observation period after preprocessing. 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 line within a preset time;

[0009] Determine the noise type based on the noise intensity at the noise source location and the degree of consistency between the time when the noise appears and the time of the dynamic change of the load. The noise type includes suppression noise, irrelevant noise, and noise to be analyzed;

[0010] Determine whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value. 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. The power line noise suppression process parameters include the preset complex tendency value of the noise distribution, the preset noise intensity, and the preset generation frequency.

[0011] Further, the calculation of the complex tendency value of the noise distribution 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:

[0012] The complexity of the power line distribution is determined by 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;

[0013] The complex tendency value of the noise distribution around the power line is determined by the sum of the ratio of the complexity of the power line distribution to the ratio of the number of types of load devices connected to the power line to the maximum number of types of load devices connected to the power line during the historical noise suppression process.

[0014] Further, the determination of the acquisition method of the power line carrier signal based on the complex type of the noise distribution around the power line includes:

[0015] If the complex type of the noise distribution around the power line is a complex type, determine to collect the power line carrier signal in a multi-sensor collaborative acquisition method;

[0016] If the complex type of the noise distribution around the power line is a simple type, determine to collect the power line carrier signal in a fixed-point collection manner with a single sensor.

[0017] Furthermore, the complex type of the noise distribution around the power line is determined according to the comparison result between the complex tendency value of the noise distribution around the power line and the preset complex tendency value of the noise distribution, including:

[0018] If the complex tendency value of the noise distribution around the power line is less than or equal to the preset complex tendency value of the noise distribution, determine that the complex type of the noise distribution around the power line is a simple type;

[0019] If the complex tendency value of the noise distribution around the power line is greater than the preset complex tendency value of the noise distribution, determine that the complex type of the noise distribution around the power line is a complex type.

[0020] Furthermore, the step of determining the noise source position based on the abnormal fluctuation of the energy spectral density of the carrier signal of the key nodes on the power line within the observation period after preprocessing includes:

[0021] Divide the observation period into a complete cycle from the operation to the stop of the load device connected to the power line;

[0022] Obtain the fluctuation range of the energy spectral density of the carrier signal of the key nodes on the power line within the observation period after preprocessing;

[0023] Compare the fluctuation range of the energy spectral density with the preset fluctuation range to determine whether the energy spectral density is an abnormal fluctuation;

[0024] Determine the noise source position based on the upstream and downstream key nodes where the abnormal fluctuation of the energy spectral density occurs.

[0025] Furthermore, the power line key nodes are determined according to the power line branch points and the noise generation frequencies of the load devices connected to the power line, including:

[0026] The power line branch points and the access points and outflow points of the load devices with noise generation frequencies greater than the preset generation frequency within a preset time are used as key nodes.

[0027] Furthermore, determining the noise type based on the noise intensity at the noise source position and the degree of consistency between the time when the noise appears and the time of load dynamic change includes:

[0028] If the noise intensity is greater than the preset noise intensity and the degree of consistency between the time when the noise appears and the time of load dynamic change is less than the preset degree of consistency, determine that the noise type is irrelevant noise;

[0029] If the noise intensity is greater than the preset noise intensity and the degree of consistency between the time when the noise appears and the time of dynamic change of the load is greater than or equal to the preset consistency degree, determine that the noise type is suppression noise;

[0030] If the noise intensity is less than or equal to the preset noise intensity, determine that the noise type is noise to be analyzed.

[0031] Further, the preset noise intensity is determined according to the historical average value of the noise intensity at the position of the noise source when the power line is in normal operation.

[0032] Further, the determination of whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value includes:

[0033] If the power line communication quality evaluation value is greater than the preset evaluation value, determine to adjust the power line noise suppression process parameters.

[0034] Further, 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.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows. The present invention calculates the complexity by considering the distribution characteristics of the power line itself (line length and number of branches), and then combines the number of types of load devices to determine the noise distribution complexity tendency value. This method can evaluate according to the specific situation of each power line. With the development of the power system and the replacement of equipment, the layout of the power line and the types of load devices will change, and this calculation method can well adapt to these changes. Each time the noise suppression process is carried out, new data (such as the updated maximum line length, maximum number of branches, and maximum number of types of load devices) can be recorded for the next calculation of the complexity tendency value. According to the comparison result between the calculated noise distribution complexity tendency value and the preset value, the signal acquisition method (single-sensor fixed-point acquisition or multi-sensor collaborative acquisition) is determined. This decision-making method based on quantitative evaluation can make the signal acquisition more reasonable and efficient. In the subsequent noise source localization step, accurate calculation of the noise distribution complexity tendency value helps to more specifically determine the key nodes of the power line. Because for power lines with different complexities, the distribution and importance of their key nodes are also different. In a complex power line system, more branch points and access points of different types of load devices may be key nodes; while in a simple power line system, the key nodes are relatively few and easy to determine. In this way, it is possible to more efficiently use the abnormal fluctuations of the carrier signal energy spectral density of the key nodes within the observation period after preprocessing to locate the noise source, thereby improving the accuracy of noise type judgment to enhance the noise suppression effect.

[0036] Furthermore, by evaluating the complex tendency value of the noise distribution around the power line and comparing it with a preset value, the present invention can accurately determine the complex type of the noise distribution, so as to select the most suitable power line carrier signal acquisition method. In the case of simple noise distribution, single-sensor fixed-point acquisition is adopted, which avoids the unnecessary costs and data processing workloads brought by using multiple sensors, improves the acquisition efficiency. By this method, it can be quickly determined to use a single sensor for fixed-point acquisition, which not only meets the signal acquisition requirements but also saves resources and time. For the power line environment with complex noise distribution, the multi-sensor collaborative acquisition method can give full play to the advantages of each sensor and comprehensively acquire the power line carrier signals from different positions and angles. In this way, the signal characteristics in the complex noise environment can be captured more accurately, and the omission or misjudgment that may occur with a single sensor can be avoided. In a simple type of noise environment, the noise sources are relatively few and easy to analyze, and the noise type can be determined faster and corresponding suppression methods can be taken. While in a complex type of noise environment, through the data acquired by multi-sensor collaboration, the distribution and characteristics of the noise can be understood more comprehensively, providing more information for accurately determining the noise type. Through the above method, the accuracy of noise type judgment is improved, and thus the noise suppression effect is enhanced.

[0037] Furthermore, by combining multiple factors such as the noise intensity, the consistency between the occurrence time and the load dynamic change time to determine the noise type, the present invention can achieve accurate classification of the noise, which enables the adoption of the most suitable suppression method or analysis strategy 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 the noise appears, potential noise problems can be discovered in a timely manner. If it is found that the noise is correlated with the operation time of a specific device, it is classified as irrelevant noise, which can avoid over-analysis of it; if there is no correlation, it is classified as suppression 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. Through the above method, the accuracy of noise type judgment is improved, and thus the noise suppression effect is enhanced.

[0038] Furthermore, the present invention determines whether to adjust the noise suppression process parameters by comparing the power line communication quality evaluation value with a preset evaluation value, enabling the system to automatically adjust according to the actual communication quality situation, achieving 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 more effectively suppress noise. By continuously monitoring and adjusting the noise suppression process parameters, the power line communication quality can be continuously optimized. As the system operates, the characteristics of the noise may change. By adjusting the parameters in a timely manner, it can be ensured that the noise suppression measures always maintain the best effect. By the above method, the accuracy of noise type judgment is improved, thereby improving the noise suppression effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 FIG. is a flowchart of the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention;

[0040] Figure 2 FIG. is a flowchart of determining the complex type of noise distribution around the power line in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention;

[0041] Figure 3 FIG. is a flowchart of determining whether to adjust the noise suppression process parameters in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention;

[0042] Figure 4 FIG. is a flowchart of determining the position of the noise source in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0045] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for 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, and therefore cannot be understood as a limitation of the present invention.

[0046] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" 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 an indirect connection through an intermediate medium, and it can be the communication inside 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 situations.

[0047] Please refer to Figures 1-4 as shown in Figure 1 the working flowchart of the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention; Figure 2 the working flowchart of determining the complex type of noise distribution around the power line in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention; Figure 3 the working flowchart of determining whether to adjust the noise suppression process parameters in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention; Figure 4 the working flowchart of determining the position of the noise source in the power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention.

[0048] The power line noise analysis method based on carrier frequency spectrum analysis according to an embodiment of the present invention includes:

[0049] Step S1: Use a sensor to collect power line carrier signals, and calculate the complex tendency value of the noise distribution around the power line based on the complexity of the power line distribution and the type and quantity of load devices connected to the power line;

[0050] Step S2: Determine the acquisition method of the power line carrier signal based on the complex type of the noise distribution around the power line, where the complex type of the noise distribution around the power line is determined according to the comparison result between the complex tendency value of the noise distribution around the power line and a preset complex tendency value of the noise distribution;

[0051] Step S3: Preprocess the collected power line carrier signals, and determine the position of the noise source based on the abnormal fluctuation of the energy spectral density of the carrier signals at the key nodes of the power line during the observation period after preprocessing, where 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 line within a preset time;

[0052] Step S4: Determine the noise type based on the noise intensity at the noise source position and the consistency between the time when the noise appears and the time of the dynamic change of the load, where the noise type includes suppressed noise, irrelevant noise, and noise to be analyzed;

[0053] Step S5: Determine whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value. 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. The power line noise suppression process parameters include a preset noise distribution complexity tendency value, a preset noise intensity, and a preset generation frequency.

[0054] In the embodiments of the present invention, the sensors include, but are not limited to, "current transformers, voltage transformers, and capacitive couplers". The preprocessing of the collected power line carrier signals includes, but is not limited to, "filtering, noise reduction, and amplification".

[0055] Specifically, in step S1, calculate the noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the type and quantity of load devices connected to the power line.

[0056] The complexity of the power line distribution is determined by the sum of the ratio of the line length of the power line to the maximum line length of the power line in 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 in the historical noise suppression process.

[0057] The noise distribution complexity tendency value around the power line is determined by the sum of the ratio of the complexity of the power line distribution to the ratio of the type and quantity of load devices connected to the power line to the maximum type and quantity of load devices connected to the power line in the historical noise suppression process.

[0058] The present invention calculates the complexity by considering the distribution characteristics of the power lines themselves (line length and number of branches), and then determines the complex tendency value of the noise distribution in combination with the number of types of load devices. This method can evaluate according to the specific conditions of each power line. With the development of the power system and the replacement of equipment, the layout of the power lines and the types of load devices will change, and this calculation method can well adapt to these changes. Each time during the noise suppression process, new data (such as the updated maximum line length, maximum number of branches, and maximum number of types of load devices) can be recorded for the next calculation of the complex tendency value. According to the comparison result between the calculated complex tendency value of the noise distribution and the preset value, the signal acquisition method (single-sensor fixed-point acquisition or multi-sensor collaborative acquisition) is determined. This decision-making method based on quantitative evaluation can make the signal acquisition more reasonable and efficient. In the subsequent noise source localization step, accurate calculation of the complex tendency value of the noise distribution helps to more specifically determine the key nodes of the power lines. Because for power lines with different complexities, the distribution and importance of their key nodes are also different. In a complex power line system, more branch points and access points of different types of load devices may be key nodes; while in a simple power line system, the key nodes are relatively few and easier to determine. In this way, the abnormal fluctuations of the carrier signal energy spectral density of the key nodes within the preprocessed observation period can be more efficiently utilized to locate the noise source, thereby improving the accuracy of noise type judgment to enhance the noise suppression effect.

[0059] 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 complex type of the noise distribution around the power line;

[0060] When the complex type of the noise distribution around the power line is a complex type, it is determined to acquire the power line carrier signal by a multi-sensor collaborative acquisition method;

[0061] When the complex type of the noise distribution around the power line is a simple type, it is determined to acquire the power line carrier signal by a single-sensor fixed-point acquisition method.

[0062] In the embodiments of the present invention, the acquisition of power line carrier signals in the single-sensor fixed-point acquisition mode includes placing a sensor at a specific position on the power line to acquire carrier signals. This position is usually a key position determined based on experience or a preliminary analysis of the power line system. For example, at the access point of the power line, the main branch point, or a position close to important load devices. The sensor continuously monitors the power line carrier signals at this point and records the time-domain or frequency-domain information of the signals (such as voltage and current changes, frequency components, etc.); the acquisition of the power line carrier signals in the multi-sensor collaborative acquisition mode includes placing sensors at multiple different positions on the power line. The selection of these positions is based on a detailed analysis of the power line system, including factors such as the topological structure of the power line (branch situation, line length, etc.), the distribution and type of connected load devices, etc. The sensors cooperate with each other to acquire power line carrier signals from different perspectives. For example, sensors are installed at each branch node of the power line, the access and outflow points of different types of load devices.

[0063] Specifically, in step S2, when determining the complex type of the noise distribution around the power line, the complex type of the noise distribution around the power line is determined according to the comparison result between the complex tendency value of the noise distribution around the power line and the preset complex tendency value of the noise distribution.

[0064] When the complex tendency value of the noise distribution around the power line is less than or equal to the preset complex tendency value of the noise distribution, it is determined that the complex type of the noise distribution around the power line is a simple type;

[0065] When the complex tendency value of the noise distribution around the power line is greater than the preset complex tendency value of the noise distribution, it is determined that the complex type of the noise distribution around the power line is a complex type.

[0066] In the embodiments of the present invention, the preset complex tendency value of the noise distribution is based on the average value of the complex tendency value of the noise distribution around the power line during the historical noise suppression process. However, the above value is not limited to this, and those skilled in the art can also adjust this value according to actual needs.

[0067] By evaluating the complex tendency value of the noise distribution around the power line and comparing it with a preset value, the present invention can accurately determine the complex type of the noise distribution, so as to select the most suitable power line carrier signal acquisition method. In the case of simple noise distribution, single-sensor fixed-point acquisition is adopted, which avoids the unnecessary costs and data processing workloads brought by using multiple sensors, improves the acquisition efficiency. By this method, it can be quickly determined to adopt single-sensor fixed-point acquisition, which not only meets the signal acquisition requirements, but also saves resources and time. For the power line environment with complex noise distribution, the multi-sensor collaborative acquisition method can give full play to the advantages of each sensor and comprehensively acquire the power line carrier signal from different positions and angles. In this way, the signal characteristics in the complex noise environment can be captured more accurately, avoiding the omission or misjudgment that may occur with a single sensor. In a simple type of noise environment, the noise sources are relatively few and easy to analyze, and the noise type can be determined faster and corresponding suppression methods can be taken. In a complex type of noise environment, through the data collected by multi-sensor collaboration, the distribution and characteristics of the noise can be understood more comprehensively, providing more information for accurately determining the noise type. By the above method, the accuracy of noise type judgment is improved, and thus the noise suppression effect is enhanced.

[0068] Specifically, in step S3, the step of determining the noise source position based on the abnormal fluctuation of the energy spectral density of the carrier signal of the key nodes on the power line during the observation period after preprocessing includes:

[0069] Step S3301, dividing the observation period into a complete cycle from the operation to the stop of the load device connected to the power line;

[0070] Step S3302, obtaining the fluctuation range of the energy spectral density of the carrier signal of the key nodes on the power line during the observation period after preprocessing;

[0071] Step S3303, comparing the fluctuation range of the energy spectral density with a preset fluctuation range to determine whether the energy spectral density is an abnormal fluctuation;

[0072] Step S3304, determining the noise source position based on the upstream and downstream key nodes where the abnormal fluctuation of the energy spectral density occurs.

[0073] In the embodiment of the present invention, determining the noise source position based on the upstream and downstream key nodes where the abnormal fluctuation of the energy spectral density occurs includes locating the noise source by comparing the position relationship between the key node where the abnormal fluctuation of the energy spectral 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 certain branch, but there is an abnormal fluctuation at the downstream key node, then the noise source is located on the load device connected to the branch line between these two nodes.

[0074] In the embodiment of the present invention, the value range of the preset fluctuation is set to -5% to 5%, but the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0075] Specifically, in step S3, the key nodes of the power line determine, according to the power line branch points and the noise generation frequencies of the load devices connected to the power line, the access points and out - flow points including the power line branch points and the load devices with noise generation frequencies greater than the preset generation frequency as the key nodes.

[0076] In the embodiment of the present invention, the preset time is set to 8 times of a complete cycle from the operation to the stop of the load devices connected to the power line, and the preset generation frequency is the average value of the noise generation frequencies of the load devices connected to the power line within the preset time. However, the above values are not limited to this, and those skilled in the art can also adjust the values according to actual needs.

[0077] 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 degree of consistency between the time when the noise appears and the time of load dynamic change;

[0078] When the noise intensity is greater than the preset noise intensity and the degree of consistency between the time when the noise appears and the time of load dynamic change is less than the preset degree of consistency, the noise type is determined to be irrelevant noise;

[0079] When the noise intensity is greater than the preset noise intensity and the degree of consistency between the time when the noise appears and the time of load dynamic change is greater than or equal to the preset degree of consistency, the noise type is determined to be suppression noise;

[0080] 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.

[0081] In the embodiment of the present invention, the degree of consistency between the time when the noise appears and the time of load dynamic change is the sum of the absolute value of the difference between the start time of the noise appearance and the load dynamic change time and the absolute value of the difference between the disappearance time of the noise and the disappearance time of the load dynamic change. The preset noise intensity is the historical average value of the noise intensity at the noise source location when the power line is in normal operation. The preset degree of consistency is the historical average value of the degree of consistency between the noise appearance time and the load dynamic change time without noise interference or in the case of a stable noise source. The load dynamic change time is the moment when the operation state of the load devices connected to the power line changes. However, the above values are not limited to this, and those skilled in the art can also adjust the values according to actual needs.

[0082] In the embodiment of the present invention, when the noise type is noise to be suppressed, the specific type of the noise is further analyzed to select the corresponding suppression method. For example, through a spectrum analyzer to analyze the noise spectrum, narrowband noise shows obvious energy concentration in a relatively narrow frequency range on the spectrum. For example, by observing the spectrogram, if it is found that the energy in the frequency band with a bandwidth of several hundred hertz 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 targeting 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 change of the operating state of the load device each time the noise appears is recorded in detail. For example, observe whether the noise appears regularly when a certain device starts, stops or switches its working mode. If it is found that the occurrence time of the noise is correlated with the operation time of a specific device, the noise is classified as irrelevant noise. If it is found that the occurrence time of the noise has no correlation with the operation time of a specific device, the noise is classified as noise to be suppressed.

[0083] The present invention determines the noise type by combining multiple factors such as the noise intensity, the consistency between the occurrence time and the load dynamic change time, etc., and can achieve accurate classification of the noise. This enables the adoption of the most suitable suppression method or analysis strategy for different types of noise in subsequent processing. For the noise to be analyzed, by recording in detail the change of the operating state of the load device when it appears, potential noise problems can be discovered in a timely manner. If it is found that the noise is correlated with the operation time of a specific device and is classified as irrelevant noise, over-analysis of it can be avoided; if there is no correlation, it is classified as noise to be suppressed and its specific type is further analyzed, which helps to prevent possible communication failures in advance and ensure the reliable operation of the power line communication system. The accuracy of noise type judgment is improved through the above method, thereby improving the noise suppression effect.

[0084] Specifically, when determining whether to adjust the parameters of the power line noise suppression process, it is determined whether to adjust the parameters of the power line noise suppression process according to the comparison result between the power line communication quality evaluation value and the preset evaluation value;

[0085] When the power line communication quality evaluation value is greater than the preset evaluation value, it is determined that the parameters of the power line noise suppression process need to be adjusted;

[0086] 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.

[0087] In the embodiment of the present invention, the power line communication quality evaluation value is one half of the sum of the bit error rate and the reciprocal of the signal-to-noise ratio, but the above value is not limited to this, and those skilled in the art can also adjust this value according to actual needs.

[0088] Specifically, in step S5, when it is determined that the parameters of the power line noise suppression process need to be adjusted, it is determined to adjust the preset noise distribution complexity tendency value with a first adjustment coefficient, the preset noise intensity with a second adjustment coefficient, and the preset generation frequency with a third adjustment coefficient.

[0089] 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. However, the above values are not limited to this, and those skilled in the art can 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.

[0090] 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, enabling the system to automatically adjust according to the actual communication quality situation, achieving 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 more effectively suppress noise. By continuously monitoring and adjusting the noise suppression process parameters, the power line communication quality can be continuously optimized. As the system operates, the characteristics of the noise may change. By adjusting the parameters in a timely manner, it can be ensured that the noise suppression measures always maintain the best effect. By the above method, the accuracy of noise type judgment is improved, thereby improving the noise suppression effect.

[0091] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the 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 replacements to the relevant technical features, and the technical solutions after these changes or replacements will all fall within the protection scope of the present invention.

[0092] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. 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 analyzing power line noise based on carrier frequency spectrum analysis, characterized in that, Including: Using a sensor to collect power line carrier signals, and calculating a noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the type and quantity of load devices connected to the power line; Determining the acquisition mode of the power line carrier signal based on the noise distribution complexity type around the power line, where the noise distribution complexity type around the power line is determined according to the comparison result between the noise distribution complexity tendency value around the power line and a preset noise distribution complexity tendency value; Preprocessing the collected power line carrier signals, and determining the noise source location based on the abnormal fluctuations of the energy spectral density of the carrier signals at key nodes of the power line within the observation period after preprocessing, where the key nodes of the power line are determined according to the power line branch points and the noise generation frequency of the load devices connected to the power line within a preset time; The steps for determining the noise source location include: Dividing the observation period into a complete cycle from the operation to the stop of the load devices connected to the power line; Obtaining the fluctuation range of the energy spectral density of the carrier signals at key nodes of the power line within the observation period after preprocessing; Comparing the fluctuation range of the energy spectral density with a preset fluctuation range to determine whether the energy spectral density is an abnormal fluctuation; Determining the noise source location based on the upstream and downstream key nodes where the abnormal fluctuation of the energy spectral density occurs; Determining the noise type based on the noise intensity at the noise source location and the consistency degree between the time when the noise appears and the time of load dynamic change, where the noise type includes suppression noise, irrelevant noise, and noise to be analyzed; Determining the noise type includes: If the noise intensity is greater than a preset noise intensity and the consistency degree between the time when the noise appears and the time of load dynamic change is less than a preset consistency degree, determining that the noise type is irrelevant noise; If the noise intensity is greater than a preset noise intensity and the consistency degree between the time when the noise appears and the time of load dynamic change is greater than or equal to a preset consistency degree, determining that the noise type is suppression noise; If the noise intensity is less than or equal to a preset noise intensity, determining that the noise type is noise to be analyzed; Determining whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value, where the power line communication quality evaluation value is determined according to the bit error rate and signal-to-noise ratio of 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 analyzing power line noise based on carrier frequency spectrum analysis according to claim 1, wherein The calculating the noise distribution complexity tendency value around the power line based on the complexity of the power line distribution and the type and quantity 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 in 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 in the historical noise suppression process; The noise distribution complexity tendency value around the power line is determined according to the sum of the ratio of the complexity of the power line distribution to the ratio of the type and quantity of load devices connected to the power line and the maximum type and quantity of load devices connected to the power line in the historical noise suppression process.

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

4. The method for analyzing power line noise based on carrier frequency spectrum analysis according to claim 3, wherein The complex type of the noise distribution around the power line is determined according to the comparison result between the complex tendency value of the noise distribution around the power line and the preset complex tendency value of the noise distribution, and includes: If the complex tendency value of the noise distribution around the power line is less than or equal to the preset complex tendency value of the noise distribution, determine that the complex type of the noise distribution around the power line is a simple type; If the complex tendency value of the noise distribution around the power line is greater than the preset complex tendency value of the noise distribution, determine that the complex type of the noise distribution around the power line is a complex type.

5. The method for analyzing power line noise based on carrier frequency spectrum analysis according to claim 4, characterized in that, 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 line within a preset time, and include: The power line branch points and the access points and outflow points of the load devices with noise generation frequencies greater than the preset generation frequency within a preset time are used as key nodes.

6. The method for analyzing power line noise based on carrier frequency spectrum analysis according to claim 5, characterized in that The preset noise intensity is determined according to the historical average value of the noise intensity at the noise source position when the power line is in a normal operation state.

7. The method for analyzing power line noise based on carrier frequency spectrum analysis according to claim 6, wherein Determining whether to adjust the power line noise suppression process parameters based on the power line communication quality evaluation value includes: If the power line communication quality evaluation value is greater than the preset evaluation value, determine to adjust the power line noise suppression process parameters.

8. The method for analyzing power line noise based on carrier frequency spectrum analysis according to claim 7, wherein The adjustment amount of the preset complex tendency value of the noise distribution 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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