Discharge noise detection method for vehicle-mounted catenary insulator, storage medium and system

Abstract

The application discloses a kind of vehicle-mounted contact network insulator discharge noise detection method, storage medium and system, the method includes sampling and carrying out frequency domain filtering, filtering by signal duty cycle and carrying out spatial consistency filtering.The application is according to the characteristics of vehicle-mounted contact network insulator discharge signal, including the width, frequency, jump and other characteristics of discharge signal, designs specific filtering algorithm, effectively utilizes the signal characteristics of vehicle-mounted detection along-line equipment data, and engine background noise, cylinder exhaust sound and vibration noise do not comply with this signal characteristic.The application is simple and convenient, not affected by speed, and can be used for various vehicle models.

Description

Technical Field

[0001] This invention relates to the field of vehicle-mounted contact network discharge detection technology, and in particular to a method, storage medium, and system for detecting discharge noise in vehicle-mounted contact network insulators. Background Technology

[0002] When a contact wire insulator experiences partial discharge due to pollution, the molecules in the discharge region undergo violent collisions, and the volume changes caused by the discharge heat. These processes generate pulse pressure waves, which in turn cause changes in sound waves, with ultrasound being a particularly characteristic component. Ultrasound refers to sound waves with frequencies greater than 20kHz that are inaudible to the human ear. The partial discharge source can be considered a point pulse sound source, following the propagation laws of mechanical waves. The sound waves propagate in the form of spherical waves, with varying propagation speeds in different media, and reflections occur at the interfaces between different media.

[0003] Utilizing the propagation characteristics of ultrasound, after acquiring ultrasonic signals using an ultrasonic sensor, it is necessary to filter out the ultrasonic signals introduced by non-discharge processes, retaining only the normal discharge signals. Since the equipment is installed on the vehicle roof, the main noise introduced includes wind noise from high-speed driving, background noise from the vehicle engine, hydraulic exhaust noise, and vehicle vibration noise. All of these noises fall within the ultrasonic frequency spectrum, with background noise from the vehicle engine, cylinder exhaust noise, and vehicle vibration noise having a significant impact on signal acquisition.

[0004] Therefore, it is necessary to develop a method, storage medium, and system for detecting discharge noise in vehicle-mounted contact network insulators to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to design a method, storage medium, and system for detecting discharge noise in vehicle-mounted contact network insulators in order to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] Methods for detecting discharge noise in vehicle-mounted overhead contact line insulators include:

[0008] Step 1: Sample and perform frequency domain filtering;

[0009] High-speed sampling of the ultrasonic probe is achieved based on the frequency band of the discharge of the contact wire insulator, and bandpass filtering is performed in the range of 20kHz-50kHz.

[0010] Step 2: Filtering is performed by setting the longitudinal distance of the discharge point;

[0011] The longitudinal distance of the discharge point is calculated using the following formula. S :

[0012] (1-1)

[0013] (1-2)

[0014] In the formula, N is the total number of signal samples. Where is the sampling frequency, v is the vehicle speed, and δ is the allowable error. S0 The set longitudinal distance of the discharge point;

[0015] Sampled data that do not satisfy formula (1-2) are identified as invalid signals and filtered out;

[0016] Step 3: Filter the signal by its duty cycle;

[0017] The formula is as follows:

[0018] (2)

[0019] In the formula, It is data of a signal with a large jump. These are all the discharge data; D is the duty cycle setting value.

[0020] Sampled data that do not satisfy formula (2) are identified as invalid signals and filtered out;

[0021] Step 4: Perform spatial consistency filtering;

[0022] Two ultrasonic probes, spaced a distance L apart, are installed on the roof of the testing vehicle. The time it takes for the two probes to capture the discharge signal, one in front of the other, satisfies the formula:

[0023] (3)

[0024] In the formula, t1 and t2 are the times when the signals are captured by the two sets of ultrasonic probes, respectively; B is the allowable error; and V is the vehicle speed. L The distance between the two sets of ultrasonic probes;

[0025] Sampled data that do not satisfy formula (3) are identified as invalid signals and filtered out.

[0026] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for detecting discharge noise in vehicle-mounted contact network insulators.

[0027] A vehicle-mounted contact wire insulator discharge noise detection system includes two sets of ultrasonic probes installed on the roof of the detection vehicle, spaced a distance L apart, a data acquisition unit, and a computer. The data acquisition unit is used to collect the acoustic signals from the ultrasonic probes and transmit them to the computer in real time. The computer contains a computer-readable storage medium.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. By effectively utilizing on-board discharge to detect driving characteristics and setting up a filter, it is simple and convenient, unaffected by vehicle speed, and can be used for various vehicle models. It can effectively filter out engine background noise, cylinder exhaust sound, and vibration noise.

[0030] 2. Parameters can be set according to the actual installation situation, such as the range of continuous discharge length and error, which improves the adaptability of the algorithm;

[0031] 3. Through algorithms, the filtering effect can be achieved physically without adding additional hardware;

[0032] 4. Through automated processing, the false alarm rate of the system can be effectively reduced, the workload of on-site personnel in verifying the data can be greatly reduced, and the maintenance efficiency of overhead contact line insulators can be improved. Attached Figure Description

[0033] Figure 1 This is a flowchart of a method for detecting discharge noise in vehicle-mounted contact network insulators according to the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0039] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" 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; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] like Figure 1 As shown, the method for detecting discharge noise in vehicle-mounted overhead contact line insulators includes:

[0042] Step 1: Sample and perform frequency domain filtering;

[0043] Since the special frequency band of the discharge of the contact wire insulator is between 20kHz and 50kHz, it is necessary to use a sampling rate of 100kHz-200kHz to achieve high-speed sampling of the ultrasonic probe and to perform frequency domain bandpass filtering of 20kHz-50kHz on the sampled data.

[0044] Step 2: Filtering is performed by setting the longitudinal distance of the discharge point;

[0045] The vehicle's speed can be determined using its photoelectric encoder; therefore, if Where is the sampling frequency (Hz), v is the vehicle speed (m / s), N is the total number of ultrasonic signal samples, S0 is the limited ultrasonic detection range (m, e.g., a distance of 10m), and δ is the allowable error distance (m). The longitudinal distance of the discharge point is calculated using the following formula. S :

[0046] (1-1)

[0047] (1-2)

[0048] Sampling data that does not satisfy formula (1-2) is considered invalid and filtered out. During different speeds, if a vehicle passes a discharge point, the longitudinal distance generated by the discharge is within a certain range depending on the vehicle's installation location. However, background noise from the engine or cylinder exhaust does not change with vehicle speed but exhibits a certain waveform on the time axis. Therefore, this method can filter out some noise. In this step, for example, if an ultrasonic signal is detected, and the amount of sampled data reaching the threshold (e.g., 40dB) is 400k, and the sampling rate is 100kHz (unit: units / second), then the sampling time is 400000 / 100000 = 4 seconds. At a speed of 80 km / h, the travel distance is 80 / 3.6*4 ≈ 88 meters. Assuming the ultrasonic wave's limited range S0 is 10 meters, then 88 meters > 10 meters, therefore the signal is considered invalid.

[0049] Step 3: Filter the signal by its duty cycle;

[0050] Contact wire discharge mainly consists of surface discharge and surface flashover. Experiments have verified that, under certain humidity conditions, the normal discharge signal of the contact wire has a duty cycle of approximately 0.1-0.3. This means that within a certain period, only about 30% of the sound pressure data shows significant jumps exceeding 40 dB, while the signal is weak or absent at other times. Engine background noise and cylinder exhaust sounds have a duty cycle between 0.6-0.9, which can essentially be considered a continuous sound pressure signal. Therefore, after a period of data acquisition, signal characteristics can be extracted by analyzing the duty cycle of the data. This method can also filter out some noise. This is data from signals with relatively large transitions (default 40dB or more). These are all the discharge data; D is the duty cycle setting value.

[0051] The formula is as follows:

[0052] (2)

[0053] Sampled data that does not meet the formula (2) are identified as invalid signals and filtered out. If 400k data points are collected in a certain interval, and 200k of them exceed the threshold (assuming 40dB), then the duty cycle is 200000 / 400000=0.5, which exceeds the duty cycle of 0.1-0.3 for normal discharge signals, and is therefore judged as an interference signal.

[0054] Step 4: Perform spatial consistency filtering;

[0055] The testing vehicle is typically 15-20 meters long. Two sets of ultrasonic probes are installed at both ends of the vehicle's roof. If the two sets of probes are spaced apart... L =10 meters. Therefore, if a contact wire discharge is detected while the vehicle is traveling at high speed, the two sets of sensors should capture the discharge signal one after the other. For example, if the vehicle speed is 20 meters per second, the time interval between the two sets of sensors capturing the discharge should be 10 / 20 = 0.5 seconds. However, for background noise from the engine, cylinder exhaust, or vibration noise, the two sets of sensors should detect the noise simultaneously without any time interval. Based on this approach, filtering for other types of noise can be achieved. The formula is as follows:

[0056] (3)

[0057] In the formula, t1 and t2 are the times when the signals are captured by the two sets of ultrasonic probes, respectively; B is the allowable error; and V is the vehicle speed. L The distance between the two sets of ultrasonic probes;

[0058] Sampled data that do not meet the formula (3) are identified as invalid signals and filtered out, and finally normal discharge ultrasonic signals are obtained.

[0059] In some embodiments, the longitudinal distance between the discharge points is set to S0 = 8 − 12 meters.

[0060] In some embodiments, the data of a signal with a large jump is above 40 dB.

[0061] In some embodiments, the duty cycle of the signal during normal discharge of the contact network is ≤0.3, and the duty cycle of the engine background noise and cylinder exhaust sound is ≥0.6.

[0062] In some embodiments, more preferably, the duty cycle of the signal for normal discharge of the contact network is between 0.1 and 0.3.

[0063] In some embodiments, more preferably, the duty cycle of the engine background noise and cylinder exhaust noise is between 0.6 and 0.9.

[0064] In some embodiments, the distance between the two sets of ultrasonic probes is L = 8-12 meters.

[0065] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for detecting discharge noise in vehicle-mounted contact network insulators.

[0066] A vehicle-mounted contact wire insulator discharge noise detection system includes two sets of ultrasonic probes installed on the roof of the detection vehicle, spaced a distance L apart, a data acquisition unit, and a computer. The data acquisition unit is used to collect the acoustic signals from the ultrasonic probes and transmit them to the computer in real time. The computer contains a computer-readable storage medium.

[0067] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting discharge noise of an overhead contact line insulator on a vehicle, characterized by, The method comprises the following steps: Step 1, sampling and frequency domain filtering; High-speed sampling of the ultrasonic probe is realized according to the frequency band of the discharge of the overhead contact line insulator, and 20kHz-50kHz band-pass filtering is performed; Step 2, filtering by setting the longitudinal distance of the discharge point; The longitudinal distance of the discharge point is calculated by the following formula S : （1-1） （1-2） where N is the total number of signal samples, is the sampling frequency, v is the vehicle speed, δ is the allowed error, S0 is the set longitudinal distance of discharge points; The sampling data not satisfying formula (1-2) is identified as invalid signal and filtered out; Step 3, filtering by signal duty cycle; The formula is as follows: （2） In the formula, is the data of a signal with a large jump, is all discharge data, D is a duty setting value; the data of a signal with a large jump is data of 40 db or more The sampling data not satisfying formula (2) is identified as invalid signal and filtered out; Step 4, spatial consistency filtering; Two sets of ultrasonic probes with a front-rear distance L are installed on the roof of the detection vehicle, and the time of capturing the discharge signal by the two sets of probes satisfies formula: （3） In the formula, t1 and t2 are respectively the time when signals are captured by the front and rear ultrasonic probes, B is an allowable error, V is the vehicle speed, L is the interval distance of the front and rear ultrasonic probes; The sampling data not satisfying formula (3) is identified as invalid signal and filtered out.

2. The method according to claim 1, characterized in that: The frequency band of the discharge of the overhead contact line insulator is between 20kHz-50kHz, and the sampling frequency of high-speed sampling is 100kHz-200kHz.

3. The method according to claim 1, characterized in that: The set longitudinal distance S0 of the discharge point is 8-12 meters.

4. The method according to claim 1, characterized in that: The signal duty cycle of the normal discharge of the overhead contact line is ≤0.3, and the duty cycle of the engine background noise and the cylinder exhaust sound is ≥0.

6.

5. The method according to claim 4, characterized in that: The signal duty cycle of the normal discharge of the overhead contact line is between 0.1-0.

3.

6. The method according to claim 4, characterized in that: The duty cycle of the engine background noise and the cylinder exhaust sound is between 0.6-0.

9.

7. The method according to claim 1, characterized in that: The front-rear distance L of the two sets of ultrasonic probes is 8-12 meters.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the steps of the overhead contact line insulator discharge noise detection method according to any one of claims 1-7.

9. A pantograph catenary insulator discharge noise detection system, characterized by, The system comprises two sets of ultrasonic probes with a front-rear distance L installed on the roof of the detection vehicle, a data collector and a computer, the data collector is used for collecting the sound signals of the ultrasonic probes and transmitting the sound signals to the computer in real time, and the computer contains a computer readable storage medium according to claim 8.

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