Cable partial discharge positioning system
By dividing the area according to the signal propagation characteristics of the cable line and setting monitoring sensors with differentiated spacing, combined with calibrated sensors and Kalman filtering algorithm, the accuracy and cost problems of traditional cable partial discharge location methods under long distance and complex structure are solved, and high-precision and low-cost cable partial discharge location is achieved.
Patent Information
- Application Number
- CN202511913734.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-20
AI Technical Summary
Traditional partial discharge location methods for cables suffer from low positioning accuracy and high cost when cables are laid over long distances and have complex structures. In particular, signal reflection and refraction have a significant impact at special locations such as cable joints and bends, leading to inaccurate monitoring.
By dividing the area according to the signal propagation characteristics of the cable line, setting up monitoring sensors with differentiated spacing, and setting up calibration sensors at the abrupt changes in spacing, the time delay is calibrated by emitting a reference UHF pulse signal through the calibration sensors. Combined with cable characteristic parameters and Kalman filtering algorithm, the accurate location of the discharge source is achieved.
It improves the accuracy of partial discharge location in cables and reduces implementation costs, adapts to long-distance and complex cable lines, and ensures signal transmission stability and positioning accuracy.
Smart Images
Figure CN121703597A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of cable partial discharge monitoring, and specifically relates to a cable partial discharge location system. Background Technology
[0002] As the core carrier of power transmission systems, the insulation performance of cables directly determines the stability and security of power supply. Partial discharge in cables is a discharge phenomenon that occurs in localized areas of the insulation material during long-term operation, influenced by factors such as dielectric aging and insulation structural defects. It often manifests as arc discharge or pulse discharge. This phenomenon continuously accelerates the deterioration of the insulation material, leading to a gradual decline in cable insulation performance. If not detected, located, and addressed in a timely manner, it can ultimately cause serious equipment failures such as cable insulation breakdown, resulting in large-scale power outages and significant economic losses.
[0003] Therefore, accurate location of partial discharge in cables is a crucial prerequisite for ensuring the safe operation of power cables. Currently, the mainstream approach in the industry is to use sensors to collect information such as electrical and ultrasonic signals generated by partial discharge, and then use the signal propagation characteristics to invert the discharge location. Among these methods, the most widely used is to use sensors with uniform spacing to acquire partial discharge information.
[0004] However, power cable lines typically extend linearly and over long distances, an objective characteristic that presents numerous unavoidable problems with traditional uniform spacing layout schemes. On one hand, reducing sensor spacing to ensure monitoring coverage and positioning accuracy leads to a significant increase in the number of sensors deployed, substantially raising the costs of equipment purchase, installation, and subsequent maintenance. Conversely, increasing sensor spacing to control costs results in accumulated signal propagation delay errors, severely impacting positioning accuracy and failing to meet actual monitoring needs. On the other hand, cable lines contain numerous joints, bends, and other special locations, which are prone to reflecting and refractioning partial discharge signals, altering the signal propagation path. Conventional uniform spacing layouts do not consider the impact of these special structures, making it impossible to achieve adaptive monitoring of these critical locations, further reducing the reliability and accuracy of partial discharge location. In summary, the shortcomings of traditional cable partial discharge location methods urgently necessitate a positioning scheme adapted to the characteristics of long-distance linear cable laying and complex structures to improve positioning accuracy and reduce implementation costs. Summary of the Invention
[0005] The present invention provides a partial discharge locating system for cables, which can effectively solve the problems in the background art.
[0006] The present invention provides a cable partial discharge locating system, comprising the following steps:
[0007] Step 1: Divide the cable line into different areas according to the signal propagation characteristics and set up monitoring sensors with different spacing, and set up calibration sensors at the points of abrupt change in spacing;
[0008] Step 2: Calibrate the time delay measurement data of adjacent monitoring sensors by calibrating the reference UHF pulse signal emitted by the calibration sensor;
[0009] Step 3: Each monitoring sensor receives the discharge power signal from the discharge cable, and extracts the signal delay data after preprocessing;
[0010] Step 4: Integrate delay data from multiple monitoring sensors and cable characteristic parameters, and calculate the power supply location using a positioning algorithm.
[0011] As a further optimization of the present invention, the regions for dividing the signal propagation characteristics of cable lines include:
[0012] A seamless, bend-free, low-attenuation direct-buried section with a burial depth of 0.8-1.2m and a signal attenuation coefficient. ≤0.2dB / m;
[0013] For a moderate attenuation transition section with a slight bend and a bend angle ≤30° or a distance of ≥3m from the nearest building, the signal attenuation coefficient of the moderate attenuation transition section is... Between 0.2 and 0.5 dB / m;
[0014] In addition, high attenuation / reflection sections including joints, bends with bend angles >30°, crossings or proximity to strong electromagnetic interference sources, and the signal attenuation coefficient of high attenuation / reflection sections. >0.5dB / m.
[0015] As a further optimization of the present invention, the distance between the low-attenuation direct-buried section and the corresponding monitoring sensor is 50-80m; the distance between the medium-attenuation transition section and the corresponding monitoring sensor is 20-50m; and the distance between the high-attenuation / reflection section and the corresponding monitoring sensor is 5-20m.
[0016] As a further optimization of the present invention, a triangular positioning monitoring sensor is installed in the high-power area of the cable joint and terminal.
[0017] As a further optimization of the present invention, the calibration sensor transmits a reference signal with a preset frequency and amplitude. This signal propagates bidirectionally along the cable and is received by an adjacent monitoring sensor to obtain a time delay error correction value.
[0018]
[0019] in, This is the theoretical time delay for the reference signal to propagate from the calibration sensor to the monitoring sensor. This indicates the time delay value at which the monitoring sensor actually receives the reference signal.
[0020] As a further optimization of the present invention, the signal preprocessing adopts a 300MHz-3GHz bandpass filter for filtering and is amplified by a gain adjustable of 20-40dB.
[0021] As a further optimization of the present invention, the positioning algorithm includes the following steps:
[0022] Combining cable characteristic parameters Correcting the actual power supply delay signal ; To adjust the parameters for the characteristics of the integrated cable, ;in, This is the attenuation coefficient correction term. , The attenuation effect coefficient, To monitor the distance between the sensor and the calibration sensor; This is a correction term for the dielectric constant. , The relative permittivity of the cable line, The dielectric constant shift, The estimated distance from the sensor to the discharge source. The speed of light in a vacuum;
[0023] Construct a set of multi-sensor time delay difference positioning equations to determine the coordinates of the power supply. :
[0024] , ; To monitor sensor coordinates, As a benchmark, it is compared with other sensors. The time delay difference is , To incorporate the corrected signal propagation speed.
[0025] As a further optimization of the present invention, it also includes combining the Kalman filtering algorithm. , The steps involve fusing data and outputting the optimal solution; among them, For the present Estimated state of the discharge source at time t, state vector , Here is the state transition matrix. For process noise, For the observation vector, For the observation matrix, This is the observation vector.
[0026] This invention provides a partial discharge location system for cables. Based on the maximum allowable spacing calculated using a time delay error-sensor spacing correlation model, the spacing of monitoring sensors is determined by combining the signal attenuation characteristics of directly buried sections, achieving sparse deployment. The core function of the linear section monitoring sensors is to assist in positioning and signal relay: on the one hand, when the discharge source is located in the linear section, preliminary positioning is achieved through the signal time delay difference between adjacent monitoring sensors, and accuracy is corrected by combining the signals from both ends for targeted focusing; on the other hand, for long-distance cable lines, the linear section monitoring sensors can serve as signal relay nodes, preventing excessive amplitude attenuation and signal distortion of the partial discharge signal due to excessive propagation distance, thus ensuring the stability of signal transmission. Attached Figure Description
[0027] Figure 1 This is a schematic diagram illustrating the principle of this embodiment. Detailed Implementation
[0028] This embodiment specifically includes the following steps:
[0029] First, different areas are divided according to the signal propagation characteristics of cable lines, and monitoring sensors with different spacing are set.
[0030] In this embodiment, the signal propagation characteristics of the cable line mainly refer to the signal attenuation coefficient. The signal attenuation coefficient was obtained based on pulse signal transmission experiments. By measuring the amplitude attenuation of the partial discharge simulated signal in different cable sections and at different propagation distances, the correlation curve between the signal attenuation coefficient and the propagation distance of each cable section was obtained by fitting.
[0031] In this embodiment, the regions defined by the signal propagation characteristics of the cable line include a low-attenuation direct-buried section, a medium-attenuation transition section, and a high-attenuation / reflection section.
[0032] Low-attenuation direct-buried sections are jointless and bendless direct-buried cables with a burial depth of 0.8-1.2m and a signal attenuation coefficient of [missing value]. The distance between the low-attenuation direct-buried section and the corresponding monitoring sensor is controlled within the range of 50-80m.
[0033] The medium attenuation transition section is a cable line section with a slight bend and a bend angle ≤30° or a distance ≥3m from the nearest building. The signal attenuation coefficient of the medium attenuation transition section is... Between 0.2 and 0.5 dB / m, the distance between the medium attenuation transition section and the corresponding monitoring sensor is controlled within the range of 20-50 m.
[0034] High attenuation / reflection sections are cable sections that include joints, bends with bend angles >30°, crossings, or proximity to strong electromagnetic interference sources. The signal attenuation coefficient of high attenuation / reflection sections... The distance between the high attenuation / reflection section and the corresponding monitoring sensor is controlled within the range of 5-20m.
[0035] Calibration sensors are set at locations where the sensor spacing changes abruptly from large to small or from small to large, including the low-attenuation direct-buried section, the medium-attenuation transition section, and the high-attenuation / reflection section.
[0036] The calibration sensors are placed at locations including abrupt changes in spacing, the start / end points of cable lines, and both sides of important joint areas, with one calibration sensor at each location. The calibration sensors have a built-in controllable UHF pulse source with an output frequency of 300MHz-3GHz, a pulse width ≤1ns, an amplitude stability error ≤±0.5dB, and support timed triggering and manual triggering with a cycle of 1-10 minutes.
[0037] The calibration sensor uses equipment of the same model and precision as the monitoring sensor to ensure the consistency between the reference signal and the monitoring signal. The calibration sensor must be placed close to nodes with abrupt changes in spacing, while avoiding sources of signal reflection interference to ensure the stability of the reference signal.
[0038] Furthermore, in this embodiment, a triangular positioning monitoring sensor is installed in the cable joint and the high-voltage power supply area of the terminal.
[0039] A triangulation-based targeted layout is employed around each cable joint and termination. Three monitoring sensors are evenly distributed around the core area of the joint / terminal, forming an equilateral triangle monitoring unit. The side lengths of the triangles are determined based on the size of the joint / terminal and its signal propagation characteristics, ensuring that all three sensors can effectively capture the partial discharge signal in that area, and that the signal propagation time delay difference meets the requirements for accurate positioning. By utilizing the triangulation principle and the time delay difference of the signals received by the three sensors, the source of discharge in high-incidence areas can be quickly and accurately located, achieving a positioning accuracy superior to linear layout methods.
[0040] Let the location of the power source to be solved be... .
[0041] deploy There are several monitoring sensors, including a targeted triangular unit monitoring sensor and a linear segment chain monitoring sensor. The coordinates of the monitoring sensors are known. .
[0042] The time delay measurement data of adjacent monitoring sensors are calibrated by calibrating the sensor to transmit a reference UHF pulse signal.
[0043] Specifically, a reference signal with a preset frequency and amplitude is emitted by a calibration sensor. This signal propagates bidirectionally along the cable and is received by adjacent monitoring sensors. Based on the known propagation speed and distance of the reference signal, the theoretical time delay of the received signal by each monitoring sensor is calculated and compared with the actual measured time delay to obtain the time delay error correction value.
[0044]
[0045] in, This represents the theoretical time delay of the reference signal propagating from the calibration sensor to the target monitoring sensor. The specific calculation is obtained by dividing the actual distance by the propagation speed. This indicates the time delay value at which the monitoring sensor actually receives the reference signal.
[0046] By incorporating the time delay error correction value into the positioning algorithm, the monitoring signal time delay in areas of abrupt changes in spacing is calibrated in real time. This avoids the accumulation of time delay errors caused by uneven spacing, ensuring the accuracy of the positioning results. The calibration process can employ a combination of periodic automatic calibration and irregular manual calibration to guarantee the continuity of calibration accuracy.
[0047] Each monitoring sensor receives the discharge power signal from the discharge cable, and extracts the signal delay data after preprocessing. Sensors Actual measured power supply delay signal .
[0048] Signal preprocessing employs a 300MHz-3GHz bandpass filter followed by adjustable gain amplification of 20-40dB. Time delay data extraction utilizes a cross-correlation and threshold-triggered fusion algorithm. Specifically, using one monitoring sensor as a baseline, the time difference is obtained by cross-correlation calculation between the signals received by other monitoring sensors and the baseline signal. This, combined with adaptive threshold triggering, achieves a time delay measurement accuracy of ≤0.1ns.
[0049] By integrating delay data from multiple monitoring sensors and cable characteristic parameters, the location of the power supply is calculated using a positioning algorithm.
[0050] Combining cable characteristic parameters Correction determines the actual power supply delay signal .
[0051] Correction parameters for the characteristics of the fusion cable:
[0052]
[0053] in, This is the attenuation coefficient correction term. , The attenuation effect coefficient, To monitor the distance between the sensor and the calibration sensor; This is a correction term for the dielectric constant. , The relative permittivity of the cable line, The dielectric constant shift, The estimated distance from the sensor to the discharge source. It is the speed of light in a vacuum.
[0054] Construct a set of multi-sensor time delay difference localization equations, using any one monitoring sensor, such as As a benchmark, it is compared with other sensors. The time delay difference is Combined with the corrected signal propagation speed Establish the distance difference equation:
[0055]
[0056] when At that time, one can obtain These equations form an overdetermined system of equations. The coordinates of the power source are then determined. .
[0057] Finally, the Kalman filtering algorithm is combined. , The data is then integrated and the optimal solution is output. That is, the current Estimated state of the discharge source at time t, state vector ; Here is the state transition matrix. For process noise, For the observation vector, For the observation matrix, This is the observation vector.
[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A partial discharge locating system for cables, characterized in that, Includes the following steps: Step 1: Divide the cable line into different areas according to the signal propagation characteristics and set up monitoring sensors with different spacing, and set up calibration sensors at the points of abrupt change in spacing; Step 2: Calibrate the time delay measurement data of adjacent monitoring sensors by calibrating the reference UHF pulse signal emitted by the calibration sensor; Step 3: Each monitoring sensor receives the discharge power signal from the discharge cable, and extracts the signal delay data after preprocessing; Step 4: Integrate delay data from multiple monitoring sensors and cable characteristic parameters, and calculate the power supply location using a positioning algorithm.
2. The cable partial discharge locating system according to claim 1, characterized in that, The regions defined by the signal propagation characteristics of cable lines include: A seamless, bend-free, low-attenuation direct-buried section with a burial depth of 0.8-1.2m and a signal attenuation coefficient. ≤0.2dB / m; For a moderate attenuation transition section with a slight bend and a bend angle ≤30° or a distance of ≥3m from the nearest building, the signal attenuation coefficient of the moderate attenuation transition section is... Between 0.2 and 0.5 dB / m; In addition, high attenuation / reflection sections including joints, bends with bend angles >30°, crossings or proximity to strong electromagnetic interference sources, and the signal attenuation coefficient of high attenuation / reflection sections. >0.5dB / m.
3. The cable partial discharge locating system according to claim 2, characterized in that, The distance between the low-attenuation direct-buried section and the corresponding monitoring sensor ranges from 50 to 80 meters; the distance between the medium-attenuation transition section and the corresponding monitoring sensor ranges from 20 to 50 meters. The distance between the high attenuation / reflection section and the corresponding monitoring sensor ranges from 5 to 20 meters.
4. The cable partial discharge locating system according to claim 1, characterized in that, Triangular positioning monitoring sensors are installed at cable joints and high-voltage power supply areas.
5. A partial discharge locating system for cables according to claim 1, characterized in that, The calibration sensor transmits a reference signal with a preset frequency and amplitude. This signal propagates bidirectionally along the cable and is received by adjacent monitoring sensors to obtain the time delay error correction value.
6. Among them, This is the theoretical time delay for the reference signal to propagate from the calibration sensor to the monitoring sensor. This indicates the time delay value at which the monitoring sensor actually receives the reference signal.
7. A partial discharge locating system for cables according to claim 1, characterized in that, Signal preprocessing uses a 300MHz-3GHz bandpass filter for filtering, followed by adjustable gain amplification of 20-40dB.
8. A partial discharge locating system for cables according to claim 1, characterized in that, The localization algorithm includes the following steps: Combining cable characteristic parameters Correcting the actual power supply delay signal ; To adjust the parameters for the characteristics of the integrated cable, ;in, This is the attenuation coefficient correction term. , The attenuation effect coefficient is... To monitor the distance between the sensor and the calibration sensor; This is a correction term for the dielectric constant. , The relative permittivity of the cable line, The dielectric constant shift, The estimated distance from the sensor to the discharge source. The speed of light in a vacuum; Construct a set of multi-sensor time delay difference positioning equations to determine the coordinates of the power supply. : ， ; To monitor sensor coordinates, As a benchmark, it is compared with other sensors The time delay difference is , To incorporate the corrected signal propagation speed.
9. A partial discharge locating system for cables according to claim 7, characterized in that, It also includes combining the Kalman filter algorithm , The steps involve fusing data and outputting the optimal solution; among them, For the present Estimated state of the discharge source at time t, state vector , Here is the state transition matrix. For process noise, For the observation vector, For the observation matrix, This is the observation vector.