A method for evaluating the safe opening distance between contact fingers of isolating switch
By setting up photoelectric sensors and vibration sensors on the high-voltage isolation switch, combined with the analysis of optical signals and vibration signals, the problem of difficult to diagnose mechanical faults in the prior art is solved, and more accurate fault detection and safe and stable operation of the power system are achieved.
Patent Information
- Application Number
- CN202411717893.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-04-08
AI Technical Summary
The prior art is difficult to effectively diagnose and monitor mechanical failures such as corrosion and jamming and inadequate stroke in high-voltage isolation switches, resulting in frequent accidents.
The photoelectric sensor and vibration sensor are provided on the isolating switch contacts. Through the acquisition of optical signals and vibration signals, spectrum analysis and multi-stage filtering processing, the position of the rigid segmentation point is determined in combination with the optical signal map and vibration signal map, the opening distance ratio is calculated, and whether there is an abnormality is determined and an alarm is called.
It improves the accuracy of position identification of the isolation switch contacts, reduces the failure rate, extends the life of the monitoring equipment, and ensures the safe and stable operation of the power system.
Smart Images
Figure CN119779141A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of high-voltage disconnectors, and in particular to a method for evaluating the safe opening distance between contact fingers of disconnectors. Background Art
[0002] High-voltage disconnectors are the most widely used high-voltage switchgear in substations, and have a great impact on the safe operation of substations. Over the years, accidents of high-voltage disconnectors caused by mechanical failures have occurred frequently and with serious consequences. At present, there are a large number of methods at home and abroad to diagnose serious failures such as insulator cracks, but there are few methods for diagnosing defects such as rust, jamming, and inadequate travel. Existing methods are mainly based on preventive measures and empirical diagnosis. Therefore, it is necessary to carry out research on mechanical status monitoring of high-voltage disconnectors to detect mechanical failures in a timely manner and prevent accidents from expanding and causing greater losses.
[0003] However, in the power system, after the disconnector opening and closing action instructions are issued, the key focus is whether the equipment completes the corresponding action and can promptly detect the abnormal state of the disconnector opening and closing position to avoid possible operating accidents. This is crucial for the safe and stable operation of the power system.
[0004] As a key component in the power system, the disconnector must be accurate and reliable in its opening and closing actions. After the opening and closing action command is issued, if the device fails to complete the corresponding action, it may cause abnormal circuit connection in the power system and even cause a major accident. Therefore, it is necessary to ensure that the opening and closing positions of the disconnector can accurately respond to the command to ensure the normal operation of the power system.
[0005] In addition, it is also crucial to detect abnormal conditions of the disconnector's open and closed positions in a timely manner. The disconnector may fail or be damaged during operation, resulting in the inability to accurately switch its open and closed positions. If the power system continues to operate in this abnormal state, it may cause serious consequences such as circuit disconnection, overload, short circuit, and even cause fire and explosion. Therefore, it is necessary to be able to detect these abnormal conditions in a timely manner, stop operation in a timely manner, and take corresponding measures to ensure the safety of the power system.
[0006] To achieve this goal, the power system should be equipped with special monitoring and protection devices. These devices should be able to monitor the operation process of the disconnector in real time, ensure the accurate completion of the opening and closing actions, and respond to abnormal situations in a timely manner.
[0007] The existing method for judging the safe opening distance of contact fingers generally adopts the method of machine vision detection, and takes photos of the contact fingers during the movement. However, the isolating switch will produce certain vibrations during the movement, which will lead to inaccuracy in the collected images to a certain extent, resulting in errors in judgment. Secondly, a camera is set on the isolating switch to shoot its movement process. The camera is in an open-air environment for a long time and it is easy to malfunction due to rain, snow, etc., resulting in the inability to perform detection. Summary of the invention
[0008] The present invention aims at the technical problems existing in the prior art and provides a method for evaluating the safe opening distance between contact fingers of an isolating switch.
[0009] The technical solution of the present invention to solve the above technical problem is as follows: a method for evaluating the safe opening distance between contact fingers of an isolating switch, the method comprising: A photoelectric sensor and a vibration sensor are arranged on the disconnector contact to collect light signals and vibration signals respectively; Perform spectrum analysis on the optical signal, extract the frequency distribution interval of the optical signal, perform multi-level filtering on the optical signal, and generate an optical signal spectrum based on the obtained optical signal; De-noising the vibration signal, and generating a vibration signal spectrum according to the de-noised vibration signal; The position of the split point is determined by combining the optical signal spectrum and the vibration signal spectrum, the time when the motor movement ends is obtained, the opening distance ratio is calculated, and whether there is an abnormality is determined based on the opening distance ratio. If an abnormality exists, an alarm is issued.
[0010] Preferably, in the step of performing multi-stage filtering on the optical signal, a multi-stage bandpass filter is used, and the multi-stage bandpass filter includes at least a low-frequency interval, a medium-frequency interval and a high-frequency interval. The low-frequency interval is used to capture the main frequency of the optical signal, the medium-frequency interval is used to capture the higher harmonics of the optical signal, and the high-frequency interval is used to filter out external interference.
[0011] Preferably, the bandwidth in the multi-stage bandpass filter is adjusted through a dynamic bandwidth adjustment mechanism. When a new optical signal is found in the low frequency band, the filter bandwidth is expanded. For the high frequency band noise bandwidth, it is adaptively adjusted according to the environmental noise characteristics to expand or shrink the high frequency suppression bandwidth.
[0012] Preferably, in the multi-stage bandpass filter, a frequency boundary buffer zone is provided between different bandwidths, and the frequency boundary buffer zone is 10-20 Hz.
[0013] Preferably, in the step of denoising the vibration signal and generating a vibration signal spectrum according to the denoised vibration signal, wavelet threshold denoising is used: The expression of the noisy signal is: s(t)=y(t)+n(t); Among them, y(t) is the true signal, n(t) is the noise signal, and s(t) is the signal with noise. Select a wavelet basis type and the level N of wavelet decomposition, perform N-level wavelet decomposition on the noisy signal to obtain the wavelet coefficients of each level, perform quantization on the high-frequency wavelet coefficients from the first level to the Nth level using an appropriate threshold, and use decorrelation to remove the noise.
[0014] Preferably, for the step of denoising the vibration signal and generating a vibration signal spectrum based on the denoised vibration signal, it further includes constructing a threshold function:
[0015] is the wavelet coefficient, k is the position coefficient, representing the position of the wavelet in the time domain; j is the scale order, representing the scale or resolution of the wavelet function; the larger j is, the smaller the scale, that is, the higher the frequency; the smaller j is, the larger the scale, that is, the lower the frequency. is the threshold; it is the hard threshold function when a = 0; it is the soft threshold function when a = 1, and 0 < a < 1 is a compromise between the hard and soft thresholds.
[0016] Preferably, the quantization methods include hard threshold quantization and soft threshold quantization.
[0017] Preferably, the upper limit value of the low-frequency interval is set to 740 Hz.
[0018] Preferably, in the step of calculating the opening distance ratio, determining whether there is an abnormality based on the opening distance ratio, and alarming when there is an abnormality, judge the opening distance ratio. If the opening distance remains unchanged, the opening distance ratio is 1. If the opening distance ratio is less than 1, it is determined that the opening distance decreases, and there is a risk of incomplete opening. If the opening distance ratio is greater than 1, it is determined that the opening distance increases. Set the opening distance ratio threshold according to the operation and maintenance requirements, and generate an alarm when it is too large or too small to judge whether the opening process of the GIS switch is in place.
[0019] Preferably, the disconnecting switch is an open-type disconnecting switch, and protective covers are provided on both the optical sensor and the vibration sensor.
[0020] The beneficial effects of the present invention are: by synchronously setting the optoelectronic sensor and the vibration sensor, it is possible to directly identify the change situation of the contact, determine the position of the contact, so as to specifically determine the opening distance ratio. In this process, by using a multi-stage band-pass filter for filtering, not only the optical signal is retained, but also the interference signal can be suppressed. Through the double-determination method, the recognition accuracy of the just-separation point is improved. Using the optoelectronic sensor and the vibration sensor can greatly reduce the failure rate and extend the life of the monitoring equipment. Description of the Drawings
[0021] Figure 1 It is a schematic diagram of the power curve showing jamming during closing provided by the present invention; Figure 2 A schematic diagram of a power curve when the circuit breaker is not in place during closing provided by the present invention. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.
[0023] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.
[0024] In the description of the present application, the term "for example" is used to mean "used as an example, illustration or description". Any embodiment described as "for example" in the present application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any technician in the field to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details to obscure the description of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.
[0025] Embodiment 1, as Figure 1 and Figure 2 As shown, a method for evaluating the safe opening distance between contact fingers of an isolating switch provided by an embodiment of the present invention comprises: A photoelectric sensor and a vibration sensor are arranged on the disconnector contact to collect light signals and vibration signals respectively; Perform spectrum analysis on the optical signal, extract the frequency distribution interval of the optical signal, perform multi-level filtering on the optical signal, and generate an optical signal spectrum based on the obtained optical signal; De-noising the vibration signal, and generating a vibration signal spectrum according to the de-noised vibration signal; The position of the split point is determined by combining the optical signal spectrum and the vibration signal spectrum, the time when the motor movement ends is obtained, the opening distance ratio is calculated, and whether there is an abnormality is determined based on the opening distance ratio. If an abnormality exists, an alarm is issued.
[0026] In this embodiment, the present invention sets a photoelectric sensor on the isolating switch contact, and the optical signal detected by the photoelectric sensor is adapted to the detection circuit. The detected optical signal is transmitted to the processing module, and the processing module performs noise reduction processing on the detected optical signal. In the present invention, a nonlinear optical denoising method is used to perform noise reduction processing on the detected optical signal.
[0027] In order to ensure that the bandwidth of the frequency domain filter covers all the frequencies of the collected optical signals, the frequency characteristics of the collected optical signals need to be analyzed first. In the detection of the contact fingers of the disconnector, the collected optical signals usually appear as characteristic signals in the low-frequency range, while the high-frequency parts are mostly environmental noise and electromagnetic interference.
[0028] Spectrum analysis: By performing spectrum analysis on optical signals under different working conditions, the frequency distribution range of the optical signals can be found. For example, the frequency of leakage optical signals is usually concentrated in the range of several hundred hertz, while high-frequency noise is usually in the range of several thousand hertz or higher. Therefore, the frequency band of the filter can be set to focus on the main frequency range of the optical signal.
[0029] By increasing the bandwidth of the system, the information transmission capacity of the optical fiber communication system can be improved, and the power density of the optical signal during transmission can be reduced, thereby reducing the impact of nonlinear optical effects.
[0030] Bandwidth division based on: In order to accurately capture the characteristics of different frequency bands of optical signals and suppress high-frequency interference signals, the frequency domain filter is designed as a multi-stage bandpass filter, and each stage of the filter corresponds to a specific frequency range.
[0031] The specific basis for bandwidth division is as follows: Low frequency range (main optical signal area): According to the frequency distribution of optical signals, the low frequency bandwidth of the filter is concentrated in the main optical frequency range. According to the results of the previous spectrum analysis, the upper limit of this frequency band can be set in the range of 740 Hz to ensure the full capture of optical signals.
[0032] Intermediate frequency interval (potential optical signal and noise mixing area): Considering that some optical signals may contain higher-frequency components, an intermediate frequency filter bandwidth interval is added to capture the higher harmonics of the optical signal. The bandwidth of this interval can be set to a range of several hundred hertz to several thousand hertz to ensure that leakage signals under some complex working conditions will not be missed.
[0033] High frequency range (noise filtering area): The noise in the high frequency part is often composed of external electromagnetic interference, transient high frequency components generated by equipment operation, etc. In order to filter out these interferences, the filter bandwidth in the high frequency range can cover frequencies of several thousand hertz and above, and directly suppress or attenuate the signals in this range to a lower level to reduce the impact on low-frequency optical signals.
[0034] Dynamic bandwidth adjustment: In practical applications, since the frequency of environmental noise may fluctuate, setting a dynamic bandwidth adjustment mechanism can improve system adaptability.
[0035] The specific implementation is as follows: Adaptive bandwidth expansion: When a new optical signal is detected in the low frequency band, the filter bandwidth can be adaptively expanded. For example, when a significant increase in the energy of the signal within the low frequency bandwidth is detected and the frequency is near the upper limit of the bandwidth, the upper limit of the frequency band can be temporarily expanded to ensure the complete capture of the optical signal.
[0036] Adaptive suppression of high-frequency noise: For the high-frequency noise bandwidth, it can be adaptively adjusted according to the characteristics of the environmental noise, appropriately expanding or shrinking the high-frequency suppression bandwidth to ensure the accuracy of signal processing.
[0037] Avoid bandwidth overlap and over-width issues: The bandwidth setting of the filter must not only cover all possible optical signals, but also avoid bandwidth overlap between frequency bands to avoid spectrum confusion.
[0038] Boundary Control: Ensures that the bandwidths of each frequency band do not overlap or mix up by setting an appropriate frequency boundary buffer between the bandwidths. This buffer can be set to 10-20 Hz to prevent signals from crossing the band.
[0039] Control of excessive bandwidth: If the filter bandwidth is set too wide, high-frequency noise may enter the optical signal frequency band, affecting the accuracy of signal extraction. The bandwidth should be controlled according to actual needs and signal characteristics to ensure the accuracy of bandpass filtering.
[0040] Frequency response and gain optimization: The frequency response curve and gain design of each frequency band filter need to ensure the filtering effect. In the optical signal section, the gain should be close to 1 to ensure that the signal is not distorted; in the high-frequency noise section, the gain should be low enough to ensure that the noise signal is effectively suppressed.
[0041] Through the above bandwidth division basis and the corresponding adaptive adjustment strategy, it can be ensured that the bandwidth selection of the frequency domain filter can not only cover all possible optical signal frequencies, but also effectively suppress the interference of high-frequency noise, thereby improving the signal extraction accuracy and anti-interference ability of the system.
[0042] The denoised optical signal is plotted as an optical signal spectrum of the contact finger during movement. The just-separation point is found through the spectrum. Generally, the just-separation point is the position where the amplitude of the optical signal is the largest.
[0043] To further ensure the accuracy of the just-closure point, a vibration sensor is set up simultaneously to collect the vibration signal of the contact finger of the disconnector during movement. Similar to the above process, the collected vibration signal is subjected to noise reduction and filtering processing. In the present invention, wavelet threshold denoising is adopted and processed by giving soft / hard threshold. The main process is as follows: The expression of the noisy signal is: s(t) = y(t) + n(t) where y(t) is the true signal, n(t) is the noise signal, and s(t) is the noisy signal.
[0044] Select a wavelet basis type and the decomposition level N of the wavelet. The noisy signal is decomposed into N layers of wavelet decomposition to obtain the wavelet coefficients of each layer. Appropriate thresholds are taken for the high-frequency wavelet coefficients from the first layer to the Nth layer for quantization, and the noise is removed by using its decorrelation. The quantization processing methods mainly include hard threshold quantization and soft threshold quantization. The hard threshold method can well retain local features such as signal edges, and the soft threshold processing is relatively smoother, but it will cause distortion phenomena such as edge blurring.
[0045] Construct a threshold function
[0046] is the wavelet coefficient, k is the position coefficient, indicating the position of the wavelet in the time domain; j is the scale order, indicating the scale or resolution of the wavelet function; the larger j is, the smaller the scale is, that is, the higher the frequency; the smaller j is, the larger the scale is, that is, the lower the frequency; is the threshold; When a = 0, it is a hard threshold function; when a = 1, it is a soft threshold function, and 0 < a < 1 is a compromise between hard and soft thresholds.
[0047] Similarly, the denoised vibration signal is plotted as a vibration signal spectrum of the contact finger during movement. The just-separation point is found through the spectrum. Generally, the just-separation point is the position where the amplitude of the vibration signal is the largest.
[0048] The specific position of the just-separation point is determined by comparison, and the specific position of the just-separation point is further determined through double determination; wait for the end time of the motor movement, and compare the end time of the motor movement with the time in the plotted spectrum to obtain the opening distance ratio.
[0049] Wait for the end time of the motor movement, and compare the end time of the motor movement with the time in the plotted spectrum to obtain the opening distance ratio.
[0050] The opening distance ratio is judged. If the opening distance remains unchanged, the opening distance ratio is 1. If the opening distance ratio is less than 1, it means that the opening distance is reduced and there is a risk of inadequate opening. If the opening distance ratio is greater than 1, it means that the opening distance is increased. Set the opening distance ratio threshold according to the needs of on-site operation and maintenance. If it is too large or too small, an alarm will be generated to determine whether the GIS switch opening process is in place.
[0051] It should be noted that the isolating switch involved in this patent is specifically an open-type isolating switch, and the optical sensor and the vibration sensor are both provided with covers for preventing wind, sand, rain and snow.
[0052] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0053] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A method for evaluating the safe opening distance between contact fingers of an isolating switch, characterized in that: The method comprises: A photoelectric sensor and a vibration sensor are arranged on the disconnector contact to collect light signals and vibration signals respectively; Perform spectrum analysis on the optical signal, extract the frequency distribution interval of the optical signal, perform multi-level filtering on the optical signal, and generate an optical signal spectrum based on the obtained optical signal; De-noising the vibration signal, and generating a vibration signal spectrum according to the de-noised vibration signal; The position of the split point is determined by combining the optical signal spectrum and the vibration signal spectrum, the time when the motor movement ends is obtained, the opening distance ratio is calculated, and whether there is an abnormality is determined based on the opening distance ratio. If an abnormality exists, an alarm is issued.
2. The method for evaluating the safe opening distance between contact fingers of an isolating switch according to claim 1, characterized in that: In the step of performing multi-stage filtering on the optical signal, a multi-stage bandpass filter is used, and the multi-stage bandpass filter includes at least a low-frequency interval, an intermediate frequency interval and a high-frequency interval. The low-frequency interval is used to capture the main frequency of the optical signal, the intermediate frequency interval is used to capture the higher harmonics of the optical signal, and the high-frequency interval is used to filter out external interference.
3. The method for evaluating the safe opening distance between contact fingers of an isolating switch according to claim 2, characterized in that: The bandwidth in the multi-stage bandpass filter is adjusted through a dynamic bandwidth adjustment mechanism. When a new optical signal is found in the low-frequency band, the filter bandwidth is expanded. For the high-frequency noise bandwidth, it is adaptively adjusted according to the environmental noise characteristics to expand or shrink the high-frequency suppression bandwidth.
4. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 2, characterized in that: In the multi-stage bandpass filter, a frequency boundary buffer is set between different bandwidths, and the frequency boundary buffer is 10-20 Hz.
5. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 1, characterized in that: The vibration signal is denoised and in the step of generating a vibration signal spectrum according to the denoised vibration signal, wavelet threshold denoising is used: The expression of the noisy signal is: s(t)=y(t)+n(t); Among them, y(t) is the real signal, n(t) is the noise signal, and s(t) is the noisy signal; Select a wavelet basis type and a wavelet decomposition level N, perform N-layer wavelet decomposition on the noisy signal, obtain the wavelet coefficients of each layer, take appropriate thresholds to quantize the high-frequency wavelet coefficients from the first layer to the Nth layer, and use decorrelation to remove noise.
6. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 5, characterized in that: The step of performing denoising on the vibration signal and generating a vibration signal spectrum according to the denoised vibration signal also includes constructing a threshold function: where \(w_{j,k}\) are wavelet coefficients, \(k\) is the position coefficient representing the position of the wavelet in the time domain, and \(j\) is the scale order representing the scale or resolution of the wavelet function; \(\lambda\) is the threshold; it is the hard threshold function when \(a = 0\); it is the soft threshold function when \(a = 1\), and \(0\lt a\lt1\) represents a compromise between the hard and soft thresholds.
7. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 5, characterized in that: The quantization methods include hard threshold quantization and soft threshold quantization.
8. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 2, characterized in that: The upper limit of the low frequency range is set to 740 Hz.
9. The method for evaluating the safe opening distance between contact fingers of a disconnector contact according to claim 1, characterized in that: Calculate the opening distance ratio, and determine whether there is an abnormality based on the opening distance ratio. In the step of alarming when an abnormality occurs, the opening distance ratio is judged. If the opening distance remains unchanged, the opening distance ratio is 1. If the opening distance ratio is less than 1, it is determined that the opening distance is reduced and there is a risk of inadequate opening. If the opening distance ratio is greater than 1, it is determined that the opening distance is increased. Set the opening distance ratio threshold according to operation and maintenance requirements. An alarm is generated when it is too large or too small to determine whether the GIS switch opening process is in place.
10. The method for evaluating the safe opening distance between contact fingers of an isolating switch according to claim 1, characterized in that: The isolating switch is an open type isolating switch, and both the optical sensor and the vibration sensor are provided with protective covers.