Cable potential safety hazard comprehensive analysis and fault positioning system based on distributed optical fibers

Abstract

The invention discloses a cable potential safety hazard comprehensive analysis and fault positioning system based on distributed optical fibers, belongs to the technical field of power cable monitoring, relates to a distributed optical fiber technology, and comprises a data acquisition unit used for acquiring fault parameters of different layout point positions of a power cable; the data analysis module is used for processing the fault parameters, the controller is used for setting a plurality of threshold values, and the controller is used for comparing the received data with the plurality of threshold values and generating and outputting a signal to the monitoring center; the monitoring center is used for giving an alarm, early warning or sending out a tripping instruction according to the generated alarm signal, early warning signal or tripping signal; comprehensive monitoring of the operation state of the cable can be realized; by analyzing the characteristics of the temperature, the vibration and the ultrasonic signals, potential safety hazards of the cable can be effectively identified, early warning of faults is achieved, by comprehensively analyzing the temperature, the vibration and the ultrasonic signals, the cable fault position can be accurately positioned, and the fault processing efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power cable monitoring, relates to distributed optical fiber technology, and particularly relates to a comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber. Background Art

[0002] As an important power transmission device in the power system, the operating state of power cables is directly related to the safe and stable operation of the power grid. Traditional power cable monitoring methods mainly rely on regular inspections and local sensor monitoring, which have problems such as limited monitoring range, poor real-time performance, and high costs.

[0003] Distributed optical fiber sensing technology has been widely used in the field of power cable monitoring due to its advantages such as anti-electromagnetic interference, corrosion resistance, long measurement distance, and high spatial resolution. However, most of the existing power cable monitoring methods based on distributed optical fiber sensing only monitor single parameters, making it difficult to comprehensively reflect the operating state and safety hazards of cables, and even more unable to achieve accurate location of local temperature anomalies, partial discharges, and faults.

[0004] Therefore, the present invention proposes a comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber. Summary of the Invention

[0005] The present invention provides a comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber, which can solve the technical problems in the prior art that power cable monitoring methods only monitor single parameters, making it difficult to comprehensively reflect the operating state and safety hazards of cables, and unable to achieve accurate location of local temperature anomalies, partial discharges, and faults.

[0006] The present invention provides a comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber, including: a data acquisition unit installed along the laying path of the power cable for obtaining fault parameters at different laying points of the power cable; the fault parameters include: temperature value Ti and ultrasonic amplitude Sj; i represents the layout point number of the distributed optical fiber temperature sensor; j represents the layout point number of the distributed optical fiber ultrasonic sensor;

[0007] a data analysis module for processing the fault parameters, and the data analysis module is used to calculate the average temperature ratio k through a calculation formula Ti and send it to the controller;

[0008] and calculate the current ratio k through a calculation formula Ii and send it to the controller; a controller that sets multiple thresholds, and the controller is used to compare the received data with multiple thresholds, generate and output signals to the monitoring center; the monitoring center is used to alarm, give early warnings, or issue trip instructions according to the generated alarm signals, early warning signals, or trip signals.

[0009] Furthermore, the data acquisition unit is a plurality of different types of sensors arranged on the power cable. The different types of sensors include: distributed optical fiber temperature sensors, distributed optical fiber vibration sensors, and distributed optical fiber ultrasonic sensors.

[0010] Furthermore, the data acquisition unit is periodically arranged along the entire length of the power cable, and the arrangement interval distances of different types of sensors are different.

[0011] Furthermore, it further includes a data processing module. The data processing module is connected to the data acquisition unit and is used for preprocessing the temperature value Ti, vibration frequency, and ultrasonic amplitude Sj collected by the data acquisition unit. The preprocessing includes denoising, filtering, and feature extraction.

[0012] Furthermore, the process of the data analysis module for processing fault parameters includes:

[0013] The data analysis module customizes a cable section ΔL with the same laying method and environment; and respectively obtains the temperature values Ti of each layout point within the cable section ΔL;

[0014] Calculate the arithmetic mean T of the temperature values Ti of each layout point within the cable section ΔL as the average temperature value T of the cable section ΔL;

[0015] Respectively calculate the temperature difference between the temperature value Ti of each layout point and the average temperature value T, denoted as temperature difference ΔTi;

[0016] Calculate the average temperature ratio k through the calculation formula Ti and send it to the controller;

[0017] wherein, the average temperature ratio k Ti is calculated as:

[0018] k Ti = ΔTi / T.

[0019] Furthermore, the cable section ΔL includes at least one data acquisition unit layout point.

[0020] Furthermore, the data analysis module calculates the maximum current-carrying capacity It under the real-time ambient temperature of the cable section ΔL 实 and send it to the controller;

[0021] The maximum current-carrying capacity It 实 is calculated as:

[0022] I0 = It 实 / kk θ

[0023] Among them, I0 is the rated current-carrying capacity of the power cable at the designed ambient temperature t3; k is the laying environment influence coefficient of the power cable except for the temperature influence; k θ is the temperature influence coefficient;

[0024] Among them:

[0025] t is the allowable long-term working temperature of the power cable core;

[0026] t 实 is the real-time ambient temperature value of the laying environment space; the laying environment space is a cable trench or a cable tunnel, etc.;

[0027] Calculate the current ratio k through the calculation formula I and send it to the controller;

[0028] Among them, the current ratio k I is calculated as follows:

[0029] K I = I 实 / It 实

[0030] I 实 is the real-time current value of the power cable.

[0031] Furthermore, the controller is set with multiple thresholds; including:

[0032] Early warning temperature threshold T1, alarm temperature threshold T2;

[0033] Ultrasonic amplitude early warning threshold S1, ultrasonic amplitude alarm parameter S2;

[0034] Early warning temperature difference ratio threshold K1; alarm temperature difference ratio threshold K2;

[0035] Alarm current ratio threshold K3.

[0036] Furthermore, the controller is used to compare the received data with multiple thresholds, generate and output signals to the monitoring center;

[0037] The process of comparison includes:

[0038] When Ti > T1, generate an early warning signal;

[0039] When Ti > T2, generate an alarm signal;

[0040] When K Ii < K3; Ti > T1, generate an alarm signal;

[0041] When K Ii < K3; Ti > T2, generate a trip signal;

[0042] When Sj > S1, a warning signal is generated;

[0043] When Sj > S2, an alarm signal is generated;

[0044] When Ti > T1; Sj > S1, an alarm signal is generated;

[0045] When Ti > T2; Sj > S2, a trip signal is generated;

[0046] When k Ti > K1, a warning signal is generated;

[0047] When k Ti > K2, an alarm signal is generated.

[0048] Furthermore, a fault location module is also provided. When a fault occurs in the power cable, the fault location module locates the fault position. The specific process includes:

[0049] When it is monitored that Ti > T2, the monitoring center detects the signal of the incoming loop of the power cable and receives the detection feedback signal. The detection feedback signal includes a trip signal, and the short - circuit fault position is captured based on the optical time - domain reflectometry principle;

[0050] When it is monitored that Sj > S2, the monitoring center detects the signal of the incoming loop of the power cable and receives the detection feedback signal. The detection feedback signal includes a trip signal, and the short - circuit fault position is captured based on the optical time - domain reflectometry principle.

[0051] Compared with the prior art, the present invention has the following technical effects:

[0052] 1. Comprehensive monitoring: The present invention can simultaneously monitor the temperature, vibration, and ultrasonic signal of the cable, realizing comprehensive monitoring of the cable operation state.

[0053] 2. Hidden danger identification: By analyzing the characteristics of the temperature, vibration, and ultrasonic signal, the potential safety hazards of the cable can be effectively identified, realizing early warning of faults.

[0054] 3. Precise positioning: By comprehensively analyzing the temperature, vibration, and ultrasonic signal, the fault position of the cable can be accurately located, improving the efficiency of fault handling.

[0055] 4. High reliability: The distributed optical fiber sensor has the advantages of anti - electromagnetic interference, corrosion resistance, etc., and can operate stably in a complex environment. Brief Description of the Drawings

[0056] Figure 1 It is a schematic structural diagram of the cable safety hazard comprehensive analysis and fault location system based on distributed optical fiber provided by the present invention. Detailed Embodiments

[0057] The following provides a detailed description of the specific embodiments of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0058] As Figure 1 shown, the embodiment of the present invention provides a comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber, including:

[0059] A data acquisition unit installed along the cable laying path; the data acquisition unit is used to obtain fault parameters at different layout points of the power cable;

[0060] Among them, the data acquisition unit is a plurality of different types of sensors arranged on the power cable, and different types of sensors include but are not limited to: distributed optical fiber temperature sensor (DTS), distributed optical fiber vibration sensor (DVS), distributed optical fiber ultrasonic sensor (DAS);

[0061] The model of the distributed optical fiber temperature sensor can be Hyperion DTS, which has high-precision temperature measurement, is suitable for long-distance power cable monitoring, supports real-time temperature mapping, and has the characteristics of monitoring local temperature anomalies of the cable; the model of the distributed optical fiber vibration sensor can be CarinaDAS / iDAS, which has ultra-high sensitivity acoustic wave monitoring and is suitable for detecting external force damage to the cable (such as construction excavation); the signal of the distributed optical fiber ultrasonic sensor is UltimaDAS, which supports high-frequency ultrasonic waves (>20kHz) and is used for detecting partial discharge of the cable.

[0062] Among them, the distributed optical fiber temperature sensor (DTS), the distributed optical fiber vibration sensor (DVS), and the distributed optical fiber ultrasonic sensor (DAS) are all based on distributed optical fiber sensing technology, and the technical characteristics of monitoring the temperature, ultrasonic waves, and vibration of the cable not only cover the whole area, but also the spatial resolution of temperature monitoring can reach 0.2m, and the spatial resolution of ultrasonic wave and vibration monitoring can reach 1m;

[0063] In a specific embodiment, the data acquisition unit is arranged periodically along the entire length of the power cable, and the layout interval distances of different types of sensors are different;

[0064] Among them, different types of sensors in the data acquisition unit are respectively used to obtain the temperature value Ti, vibration frequency, and ultrasonic amplitude Sj;

[0065] In this application, i represents the layout point number of the distributed optical fiber temperature sensor; j represents the layout point number of the distributed optical fiber ultrasonic sensor;

[0066] It is known that partial discharge of the cable will generate physical phenomena of heat and ultrasonic waves, where the ultrasonic waves have a characteristic frequency of 40 kHz;

[0067] The data acquisition unit is electrically connected to a data processing module, and the data processing module is used to preprocess the temperature value Ti, vibration frequency, and ultrasonic amplitude Sj collected by the data acquisition unit. The preprocessing includes denoising, filtering, feature extraction, etc.; the data processing module is connected to a data analysis module, and the data analysis module is used to analyze the data processed by the data processing module and establish a mapping relationship between the operating state of the power cable and temperature, vibration frequency, and ultrasonic amplitude;

[0068] Specifically, the data analysis module adopts a combination of manually designed features and machine automatically extracted features, including the following steps:

[0069] The data analysis module customizes a cable section ΔL with the same laying method and environment; and respectively obtains the temperature value Ti of each layout point within the cable section ΔL;

[0070] Among them, the cable section ΔL includes at least one layout point of the data acquisition unit;

[0071] Calculate the arithmetic mean T of the temperature values Ti of each layout point within the cable section ΔL as the average temperature value T of the cable section ΔL;

[0072] Respectively calculate the temperature difference between the temperature value Ti of each layout point and the average temperature value T, denoted as temperature difference ΔTi;

[0073] Calculate the average temperature ratio k through the calculation formula Ti and send it to the controller; among them, the average temperature ratio k Ti is calculated to determine whether partial discharge or single-phase grounding has occurred through the average temperature ratio;

[0074] Among them, the average temperature ratio k Ti is calculated as follows:

[0075] k Ti =ΔTi / T

[0076] The data analysis module calculates the maximum current-carrying capacity Ii of the cable section ΔL under the real-time ambient temperature and sends it to the controller;

[0077] It should be noted that the real-time ambient temperature is the temperature of the space where the cable section ΔL is laid;

[0078] The maximum current-carrying capacity It 实 is calculated as follows:

[0079] I0 = It 实 / kkθ

[0080] Among them, I0 is the rated current-carrying capacity of the power cable at the designed ambient temperature t3; k is the laying environment influence coefficient of the power cable except for the temperature influence; k θ is the temperature influence coefficient;

[0081] Among them:

[0082] t is the allowable long-term working temperature of the power cable core;

[0083] t 实 is the real-time ambient temperature value of the laying environment space; the laying environment space is a cable trench or a cable tunnel, etc.;

[0084] Calculate the current ratio k through the calculation formula I and send it to the controller;

[0085] Among them, the current ratio k I is calculated as follows:

[0086] K I =I 实 / It 实

[0087] I 实 is the real-time current value of the power cable;

[0088] In a specific embodiment, when the measured temperature value Ti of the power cable is greater than the threshold value, and the real-time current value is significantly less than the maximum current-carrying capacity, it indicates that the cable is locally overloaded or a single-phase ground fault has occurred. Therefore, it can make up for the deficiency of the cable loop overload protection, and can also be used as a backup protection or auxiliary protection for the failure of the single-phase ground protection;

[0089] The data analysis module in this application is also connected to a controller, and the controller is used to receive the result signal processed by the data analysis module and execute the result according to the result signal;

[0090] Obviously, it can be known that the controller is also connected to the data processing module to synchronously obtain the data processed by the data processing module;

[0091] Specifically, the controller is provided with multiple thresholds; specifically including:

[0092] Early warning temperature threshold T1, alarm temperature threshold T2;

[0093] Ultrasonic amplitude early warning threshold S1, ultrasonic amplitude alarm parameter S2;

[0094] Early warning temperature difference ratio threshold K1; alarm temperature difference ratio threshold K2;

[0095] Alarm current ratio threshold K3;

[0096] The controller is used to compare the received data with multiple thresholds, generate and output signals to the monitoring center;

[0097] Among them, the specific process of comparison includes:

[0098]

[0099] Specifically, the monitoring center is used to alarm or give early warning according to the generated alarm signal or early warning signal; remind the operation and maintenance personnel to take measures in time.

[0100] It should be noted that within the safe distance range of the power cable path, learn the vibration frequency characteristics of manual excavation and mechanical operation;

[0101] Judge whether there is a potential hidden danger of mechanical damage to the power cable according to the obtained vibration frequency, and send out an alarm signal; specifically:

[0102] Identify the vibration spectrum characteristics of the excavator through machine learning. The vibration spectrum characteristics are periodic impact vibrations of 50 - 500 Hz, the signal intensity > 0.1 με, and the duration is long. When the vibration spectrum characteristics are identified, an early warning signal will be sent;

[0103] Identify the vibration spectrum characteristics of manual excavation through machine learning. The vibration spectrum characteristics of manual excavation are low-frequency and irregular vibrations less than 50 Hz, with a low amplitude but continuous. When the vibration spectrum characteristics are identified, an early warning signal will be sent.

[0104] In addition, a fault location module is also set in this application. The fault location module locates the fault location. The specific process includes:

[0105] When it is monitored that Ti > T2, the monitoring center detects the signal of the incoming circuit of the power cable and receives the detection feedback signal. The detection feedback signal includes a trip signal, and the short-circuit fault location is captured based on the optical time domain reflectometry principle;

[0106] When it is monitored that Sj > S2, the monitoring center detects the signal of the incoming circuit of the power cable and receives the detection feedback signal. The detection feedback signal includes a trip signal, and the short-circuit fault location is captured based on the optical time domain reflectometry principle.

[0107] The above discloses only several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. Comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber, characterized in that, Including: A data acquisition unit for obtaining fault parameters at different installation points of a power cable and installed along the laying path of the power cable; The fault parameters include: temperature value Ti and ultrasonic amplitude Sj; i represents the distribution point number of the distributed optical fiber temperature sensor; j represents the distribution point number of the distributed optical fiber ultrasonic sensor; The data analysis module for processing fault parameters, and the data analysis module is used to calculate the average temperature ratio k through a calculation formula Ti and send it to the controller; and calculate the current ratio k through a calculation formula Ii and send it to the controller; A controller that sets multiple thresholds, which is used to compare the received data with the multiple thresholds, generate and output signals to the monitoring center; the monitoring center is used to alarm, give early warning or issue a tripping instruction according to the generated alarm signal, early warning signal or tripping signal.

2. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber as claimed in claim 1, wherein, The data acquisition unit is multiple different types of sensors arranged on the power cable, and the different types of sensors include: distributed optical fiber temperature sensors, distributed optical fiber vibration sensors, and distributed optical fiber ultrasonic sensors.

3. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 2, wherein, The data acquisition unit is arranged periodically along the entire length of the power cable, and the distribution intervals of different types of sensors are different.

4. The comprehensive analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 1, characterized in that, It also includes a data processing module, which is connected to the data acquisition unit. The data processing module is used to preprocess the temperature value Ti, vibration frequency, and ultrasonic amplitude Sj collected by the data acquisition unit, and the preprocessing includes denoising, filtering, and feature extraction.

5. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 1, wherein, The process of the data analysis module for processing fault parameters includes: The data analysis module customizes a cable section ΔL with the same laying method and environment; and respectively obtains the temperature values Ti of each installation point within the cable section ΔL; Calculate the arithmetic mean T of the temperature values Ti of each installation point within the cable section ΔL as the average temperature value T of the cable section ΔL; Respectively calculate the temperature difference between the temperature value Ti of each installation point and the average temperature value T, denoted as temperature difference ΔTi; Calculate the average temperature ratio k through the calculation formula Ti and send it to the controller; Among them, the average temperature ratio k Ti is calculated as follows: k Ti = ΔTi / T 6. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 5, characterized in that, The cable section ΔL includes at least one data acquisition unit installation point.

7. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber as claimed in claim 5, wherein The data analysis module calculates the maximum current-carrying capacity It of the cable section ΔL at the real-time ambient temperature 实 and sends it to the controller; The maximum current-carrying capacity It 实 is calculated as follows: I0 = It 实 / kk θ Wherein, I0 is the rated current-carrying capacity of the power cable at the designed ambient temperature t3; k is the laying environment influence coefficient of the power cable except for the influence of temperature; k θ is the temperature influence coefficient; Wherein: t is the allowable long-term working temperature of the power cable core; t 实 is the real-time ambient temperature value of the laying environment space; wherein the laying environment space is a cable trench or a cable tunnel; Calculate the current ratio k through the calculation formula I and send it to the controller; Among them, the current ratio k I is calculated as follows: K I = I 实 / It 实 I 实 is the real-time current value of the power cable.

8. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 1, characterized in that, The controller is set with multiple thresholds; including: Early warning temperature threshold T1, alarm temperature threshold T2; Ultrasonic amplitude early warning threshold S1, ultrasonic amplitude alarm parameter S2; Early warning temperature difference ratio threshold K1; alarm temperature difference ratio threshold K2; Alarm current ratio threshold K3.

9. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 8, characterized in that, The controller is used to compare the received data with the multiple thresholds, generate and output signals to the monitoring center; The process of comparison includes: When Ti > T1, generate an early warning signal; When Ti > T2, generate an alarm signal; When K Ii < K3; When Ti > T1, an alarm signal is generated; When K Ii < K3; When Ti > T2, a trip signal is generated; When Sj > S1, generate an early warning signal; When Sj > S2, generate an alarm signal; When Ti > T1; Sj > S1, generate an alarm signal; When Ti > T2; Sj > S2, generate a tripping signal; When k T > K1, a warning signal is generated; When k T > K2, an alarm signal is generated.

10. The integrated analysis and fault location system for cable safety hazards based on distributed optical fiber according to claim 1, characterized in that, A fault location module is also provided, and the process of the fault location module for locating the fault position includes: When it is monitored that Ti > T2, the monitoring center detects the signal of the incoming loop of the power cable and receives the detection feedback signal, where the detection feedback signal includes a tripping signal, and captures the short-circuit fault position according to the optical time domain reflectometry principle; When it is monitored that Sj > S2, the monitoring center detects the signal of the incoming loop of the power cable and receives the detection feedback signal, where the detection feedback signal includes a tripping signal, and captures the short-circuit fault position according to the optical time domain reflectometry principle.

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