CN107632240B - Overhead cable current data primary analysis method, health state monitoring method and system - Google Patents
Overhead cable current data primary analysis method, health state monitoring method and system Download PDFInfo
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Abstract
The invention belongs to the technical field of power monitoring, and provides an overhead cable current data analysis method which comprises the steps of preprocessing a current signal, carrying out differential analysis on the signal, extracting a difference extreme point, and finally comparing a distribution waveform of the difference extreme point with a reference waveform to judge whether the health state of an overhead line cable is normal. The invention also provides a method for monitoring the health state of the overhead cable, which comprises the steps of current acquisition, GPS synchronous clock calibration, base station data acquisition and recording, base station data analysis, abnormal data acquisition, fault database establishment, management station data analysis, fault alarm and GPS graphic display. Through the technical scheme, the problems that in the prior art, early warning cannot be performed in advance and accidents cannot be prevented in the research on the faults of the overhead line cable are solved.
Description
Technical Field
The invention belongs to the technical field of power monitoring, and relates to an overhead line cable current data analysis method, a health state monitoring method and a health state monitoring device.
Background
Overhead lines are generally erected outdoors by cables without protective jackets and are in various severe use environments such as severe summer and cold, wind, rain and the like for years. The overhead line has long outdoor erection distance, generally, the erection distance is several kilometers to dozens of kilometers, and the erection distance of part of high-voltage lines is several hundreds to thousands of kilometers. The cable is qualified after being produced and delivered, and is called as healthy; the state of the cable during use is referred to as the health of the cable. As the service time increases, the cable begins to suffer from various problems such as aging, increased resistance, strand breakage, etc., which are called a decrease in the health of the cable. The health decline of the cable is a long-term cumulative process that is not easily discovered in the short term. The newly produced cable is erected on the line, and the safety performance of the overhead line at the initial stage can be ensured. As the use time of the overhead line increases, various faults of the overhead line gradually occur due to the decrease of the health state of the cable.
At present, researches on various faults possibly occurring on an overhead line cable mainly focus on various sudden faults caused by external force factors, such as short-circuit faults, open circuit faults and the like, and researches on the problems mainly focus on two aspects.
On one hand, the research and the application of the relay protection theory after the fault occurs are provided. CN105974232A discloses a power grid fault diagnosis method suitable for a high-voltage transmission network, comprising the following steps of obtaining switching value and electric quantity information in a power grid; step two, determining a fault range according to the switching value and electric quantity information obtained in the step one; step three, determining all fault equipment in the fault range obtained in the step two according to the incidence relation between the protection signal and the fault equipment; step four, simplifying a protection model of the high-voltage power grid, and establishing a 71EC61850 high-voltage power grid model; and step five, determining a target function according to the high-voltage power grid model established in the step four, and detecting whether the fault equipment obtained in the step three has the conditions of protection refusal and switch refusal to obtain protection action information. And fault diagnosis is performed based on the relay protection model, the wave recording information and the multi-source information of the switch, so that the positioning accuracy is greatly improved. CN105203866A discloses a new method for online fault diagnosis of 110kVXLPE cross-connect cables, namely a trace method. The method comprises the steps of collecting parameters of circulating current and operating voltage of a grounding wire of a metal sheath of a cable through an online monitoring system, and constructing a track graph integrating two parameters in the same time period after the parameters are transmitted to a computer. Any fault corresponds to different track maps, and the difference between the track maps and the normal situation is analyzed and compared by using a digital image processing technology to accurately diagnose the fault.
Another aspect is ranging of line fault points after a fault occurs. CN205643604U discloses a high-voltage cable fault diagnosis device, which includes an arithmetic processor, a temperature sensor, an optical fiber wave detector, a pulse signal receiver, an optical fiber signal receiver/transmitter, an alarm part, and a battery part, and by utilizing the mutual cooperation of the components, the fault occurrence point in the cable can be accurately determined, and not only the position of the fault occurrence point can be determined, but also the specific reason of the fault occurrence can be obtained. CN102928743A provides a technical solution of a method for detecting a fault of a power line, and when a fault current at a certain location is known, the location of a fault point can be quickly calculated, so as to quickly find and remove the fault point of the power line, and quickly recover power transmission to a trip circuit.
All of these prior arts have been studied on power transmission lines in terms of grid fault diagnosis methods, fault point detection, and the like. However, the research focuses on diagnosing the type of accident and measuring the location of the accident, and there is a lack of research on the prior accident. If the health state of the overhead line cable is monitored before an accident occurs, when the health state of the cable goes wrong, the health state of the cable is found in time and measures are taken, so that the accident caused by the decline of the health state of the cable can be avoided.
Disclosure of Invention
The invention provides a primary analysis method of overhead cable current data, a health state monitoring method and a device, and solves the problems that the research on overhead line cable faults in the prior art cannot be early warned and accidents cannot be prevented.
The technical scheme of the invention is realized as follows:
the overhead cable current data primary analysis method comprises the following steps,
step 41: preprocessing a current signal, namely removing power frequency 50Hz signals from the current signals at two positions on one phase of the overhead cable to obtain high-frequency current signals at the two positions, and respectively recording the high-frequency current signals as f (K1) and f (K2);
step 42: performing difference analysis on the signals, performing difference analysis on f (K1) and f (K2), if the signals are the same, monitoring the health state of the line cable to be normal, and if the signals are not the same, performing wavelet analysis on f (K1) -f (K2);
step 43: extracting the extreme difference points, extracting the extreme difference points of wavelet analysis in the step 42, and sequencing according to time to obtain the extreme difference point distribution waveform;
step 44: and (4) analyzing data, comparing the distribution waveform of the extreme points of the difference with a reference waveform, and judging whether the health state of the overhead line cable is normal or not.
The invention also provides a method for monitoring the health state of the overhead cable, which comprises the following steps:
step 1: current collection, at least two current collectors on the overhead cable distribute corresponding numbers and IP addresses, collect position current signals of the current collectors, and send the position current signals to a base station in a wireless mode;
step 2: GPS synchronous clock calibration, according to the difference of each current collector from the base station, considering the signal transmission time difference to calibrate the time;
and step 3: acquiring and recording data of a base station, wherein the base station receives and records the data synchronously calibrated by a GPS clock;
and 4, step 4: analyzing base station data, wherein the base station performs primary analysis on the current data of the overhead line cable according to the data recorded in the step 3, ignores normal data and transmits abnormal data to a management station in a wireless transmission mode;
and 5: acquiring abnormal data, wherein a management station receives and records the abnormal data sent by a base station;
step 6: establishing a fault database;
and 7: and (5) analyzing data of the management station, performing secondary analysis on the current data by the management station according to the data recorded in the step (5) to obtain a difference extreme point, a characteristic parameter, a time sequence and a frequency, and then matching the result of the secondary analysis on the current data with the fault data in the fault database by using fuzzy pattern recognition to obtain the fault type of the overhead line cable.
As a further technical proposal, the method also comprises the following steps after the step 7,
and 8: the method comprises the following steps of performing fault alarm, namely informing an operator on duty in an acousto-optic and electric mode for an event which is judged to be an overhead line cable fault by a management station, and displaying a fault code for the operator on duty;
and step 9: and GPS graphic display, namely displaying the position of the fault overhead line cable on a GPS graphic, and enabling a person on duty to accurately judge the position coordinate of the fault overhead line cable according to the graphic display and take measures in a targeted manner.
As a further technical solution, in step 6,
step 61: carrying out fault simulation tests on the overhead line cable in different environments, and recording fault types and corresponding fault data;
step 62: the method comprises the following steps of (1) recording fault types and corresponding fault data of faults of overhead line cables in actual use environments;
and step 63: and step 61 and step 62, storing the fault types and the fault data in a fault database in a one-to-one correspondence manner, and allocating corresponding fault codes to the fault types.
As a further technical solution, in step 7, the secondary analysis of the current data includes the following steps:
step 71, performing difference analysis on the signals, and performing wavelet analysis on the difference between high-frequency current signals f (K1) and f (K2) of the abnormal data;
and step 72, extracting the extreme value point of the difference, the characteristic parameters, the time sequence and the frequency in the step 71.
As a further technical solution, in step 7, the fuzzy pattern recognition includes the following steps:
step 73, calculating the similarity between the result of the secondary analysis of the current data in the step 7 and the fault data in the step 6, and recording the similarity as a numerical value of 0-1;
and step 74, identifying the fault type and the fault possibility according to the numerical value of the similarity.
According to a further technical scheme, the closer the numerical value of the similarity is to 1, the higher the possibility that the overhead line cable is the type of fault is, the closer the similarity is to 0, and the lower the possibility that the overhead line cable is the type of fault is.
The invention also provides a system for monitoring the health state of the overhead cable, which comprises
At least two current collectors arranged on the overhead line cable, the current collectors comprise a controller, and a Rogowski coil and a GPS synchronous clock which are both connected with the controller,
the controller is connected with the base station data acquisition system, the base station data analysis system, the abnormal data acquisition system, the fault database and the management station data analysis system in sequence,
the two ends of the Rogowski coil are butt-jointed and sleeved on the overhead line cable, the sampling frequency of the Rogowski coil is 1MHz, the controller transmits the acquired current signal data to the base station data acquisition system in a wireless transmission mode,
the GPS synchronous clock is synchronous with the satellite GPS synchronous clock, and is the GPS synchronous clock which performs time calibration according to the difference of the distance of each Rogowski coil from the base station and by considering the time difference of signal transmission.
As a further technical scheme, the system also comprises a fault alarm device which is connected with the management station data analysis system, the fault alarm device is connected with a GPS graphic display system, and the GPS graphic display system comprises a plurality of GPS positioning devices which are arranged on the overhead line cable.
The invention has the following using principle and beneficial effects:
the invention has the beneficial effects that:
1. the primary analysis of the current data is used for preliminarily judging the health condition of the overhead line cable, neglecting the current data which is preliminarily judged to be normal, continuing to acquire the current data of a new round, and carrying out subsequent complex judgment on the current data which is preliminarily judged to be abnormal. The distribution waveform of the difference extreme points is obtained by carrying out difference analysis on the high-frequency signal, the distribution waveform of the difference extreme points is compared with the reference waveform, data with the error value within +/-10% of the reference waveform is judged as normal data, and if the data is abnormal data, the method is simple in calculation process and direct in judgment method, subsequent complex operation is not needed for the current signal with the normal judgment result, resources are saved, and the monitoring speed is improved.
2. The current data analysis method adopts a wavelet theory analysis method, and the high-frequency current signals are gradually subjected to multi-scale refinement to finally achieve high-frequency time subdivision, so that any details of the signals can be focused, accurate judgment can be made, and the occurrence of misjudgment is reduced.
3. The invention can still continue the live-line operation when the overhead line cable has a local fault, but has the potential safety hazard which is difficult to discover.
4. One part of the fault database is used for carrying out fault simulation tests on the type of overhead line cable under different environments to obtain fault data, and then the fault data are recorded in the fault database, the other part of the fault database is used for recording the fault data in the fault database according to the data acquired when the overhead line cable breaks down in the actual using environment, the faults are accumulated according to the experience of workers, and the fault data are continuously supplemented and accumulated in the actual application, so that the fault database is ensured to cover all fault types, and accurate fault judgment is carried out; and corresponding fault codes are allocated to the fault types, so that the fault information is displayed simply and clearly.
5. Fuzzy pattern recognition is characterized in that a fuzzy mathematical method is introduced, the result of secondary analysis of current data is matched with the fault type in a fault database, a fuzzy technology is used for designing an overhead line cable health state recognition system, the structure is simple, the range is wide, the thinking process of human brain is simulated deeply, and therefore the overhead line cable health state is classified and recognized more effectively.
6. The Rogowski coil is an open-loop hollow flexible coil, and two ends of the Rogowski coil are butted and sleeved on the overhead line cable, so that the normal work of the overhead line cable is not influenced; compared with a mutual inductor, the Rogowski coil has no problem of magnetic saturation, and can also measure high-frequency signals of overhead line cables.
The GPS synchronous clock is synchronous with the satellite GPS synchronous clock, the time difference of signal transmission is considered according to the difference of the distance between each Rogowski coil and the base station, time calibration is carried out, and misjudgment caused by the asynchronous clock of data transmission is avoided.
7. The GPS graphic display system can display the specific position and the fault type of the fault overhead cable, and an operator on duty can accurately judge the position coordinate and the phase sequence attribute of the fault cable according to graphic display, and take measures with pertinence.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a schematic diagram of a primary analysis process of overhead cable current data according to the present invention;
FIG. 2 is a schematic flow diagram of a method for monitoring the health of an overhead cable according to the present invention;
FIG. 3 is a schematic view of a data analysis process of a management station according to the present invention;
FIG. 4 is a schematic block diagram of an overhead cable health monitoring system according to the present invention;
FIG. 5 is a schematic diagram of the overhead cable health monitoring system distribution of the present invention;
FIG. 6 is a schematic diagram of a fault tree in accordance with the present invention;
in the figure: the system comprises a 1-Rogowski coil, a 2-GPS synchronous clock, a 3-base station data acquisition system, a 4-base station data analysis system, a 5-abnormal data acquisition system, a 6-fault database, a 7-management station data analysis system, an 8-fault alarm device, a 9-GPS graphic display system, a 10-fixed point, an 11-overhead line iron tower, a 12-base station and a 13-management station.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
As shown in fig. 1 to 6, the method for primary analysis of overhead cable current data provided by the present invention comprises the following steps,
step 41: preprocessing a current signal, namely removing power frequency 50Hz signals from the current signals at two positions on one phase of the overhead cable to obtain high-frequency current signals at the two positions, and respectively recording the high-frequency current signals as f (K1) and f (K2);
step 42: performing difference analysis on the signals, performing difference analysis on f (K1) and f (K2), if the signals are the same, monitoring the health state of the line cable to be normal, and if the signals are not the same, performing wavelet analysis on f (K1) -f (K2);
step 43: extracting the extreme difference points, extracting the extreme difference points of wavelet analysis in the step 42, and sequencing according to time to obtain the extreme difference point distribution waveform;
step 44: and (4) analyzing data, comparing the distribution waveform of the extreme points of the difference with a reference waveform, and judging whether the health state of the overhead line cable is normal or not.
The primary analysis of the current data is used for preliminarily judging the health condition of the overhead line cable, neglecting the current data which is preliminarily judged to be normal, continuing to acquire the current data of a new round, and carrying out subsequent complex judgment on the current data which is preliminarily judged to be abnormal. The distribution waveform of the difference extreme points is obtained by carrying out difference analysis on the high-frequency signal, the distribution waveform of the difference extreme points is compared with the reference waveform, data with the error value within +/-10% of the reference waveform is judged as normal data, and if the data is abnormal data, the method is simple in calculation process and direct in judgment method, subsequent complex operation is not needed for the current signal with the normal judgment result, resources are saved, and the monitoring speed is improved.
The current data analysis method adopts a wavelet theory analysis method, and the high-frequency current signals are gradually subjected to multi-scale refinement to finally achieve high-frequency time subdivision, so that any details of the signals can be focused, accurate judgment can be made, and the occurrence of misjudgment is reduced.
The invention also provides a method for monitoring the health state of the overhead cable, which comprises the following steps:
step 1: current collection, at least two current collectors on the overhead cable distribute corresponding numbers and IP addresses, collect position current signals of the current collectors, and send the position current signals to a base station 12 in a wireless mode;
step 2: GPS synchronous clock calibration, which is to take the signal transmission time difference into consideration according to the difference of the position of each current collector from the base station 12 to carry out time calibration;
and step 3: base station data acquisition records, and the base station 12 receives and records data after GPS clock synchronous calibration;
and 4, step 4: analyzing base station data, wherein the base station 12 performs primary analysis on the current data of the overhead line cable according to the data recorded in the step 3, ignores normal data and transmits abnormal data to the management station 13 in a wireless transmission mode;
and 5: acquiring abnormal data, wherein the management station 13 receives and records the abnormal data sent by the base station 12;
step 6: establishing a fault database 6;
and 7: and (3) analyzing data of the management station, wherein the management station 13 performs secondary analysis on the current data according to the data recorded in the step (5) to obtain a difference extreme point, a characteristic parameter, a time sequence and a frequency, and then matches the result of the secondary analysis on the current data with the fault data in the fault database 6 by using fuzzy pattern recognition to obtain the fault type of the overhead line cable.
The invention can still continue the live-line operation when the overhead line cable has a local fault, but has the potential safety hazard which is difficult to discover.
Further, the step 6 is specifically that,
step 61: carrying out fault simulation tests on the overhead line cable in different environments, and recording fault types and corresponding fault data;
step 62: the method comprises the following steps of (1) recording fault types and corresponding fault data of faults of overhead line cables in actual use environments;
and step 63: the fault types and the fault data in the steps 61 and 62 are stored in the fault database 6 in a one-to-one correspondence manner, and corresponding fault codes are allocated to the fault types.
One part of the fault database 6 is used for carrying out fault simulation tests on the type of overhead line cable under different environments to obtain fault data, and then the fault data are recorded in the fault database 6, the other part of the fault database is used for recording the fault data in the fault database 6 according to the data collected when the overhead line cable breaks down in the actual using environment, the faults are accumulated according to the experience of workers, and are continuously supplemented and accumulated in the actual application, so that the fault database 6 is ensured to cover all fault types, and accurate fault judgment is carried out; and corresponding fault codes are allocated to the fault types, so that the fault information is displayed simply and clearly.
Further, in step 7, the secondary analysis of the current data includes the following steps:
step 71, performing difference analysis on the signals, and performing wavelet analysis on the difference between high-frequency current signals f (K1) and f (K2) of the abnormal data;
and step 72, extracting the extreme value point of the difference, the characteristic parameters, the time sequence and the frequency in the step 71.
Further, in step 7, the fuzzy pattern recognition comprises the following steps:
step 73, calculating the similarity between the result of the secondary analysis of the current data in the step 7 and the fault data in the step 6, and recording the similarity as a numerical value of 0-1;
and step 74, identifying the fault type and the fault possibility according to the numerical value of the similarity.
Fuzzy pattern recognition is realized by introducing a fuzzy mathematical method, the result of secondary analysis of current data is matched with the fault type in the fault database 6, and a fuzzy technology is used for designing the overhead line cable health state recognition system.
Further, according to the fact that the closer the numerical value of the similarity is to 1, the higher the possibility that the overhead line cable is of the type of fault is, the closer the similarity is to 0, the lower the possibility that the overhead line cable is of the type of fault is.
The invention also provides a system for monitoring the health state of the overhead cable, which comprises
At least two current collectors arranged on the overhead line cable, the current collectors comprise a controller, a Rogowski coil 1 and a GPS synchronous clock 2 which are connected with the controller,
the controller is connected with a base station data acquisition system 3, a base station data analysis system 4, an abnormal data acquisition system 5, a fault database 6 and a management station data analysis system 7 in sequence,
the two ends of the Rogowski coil 1 are butt-jointed and sleeved on an overhead line cable, the sampling frequency of the Rogowski coil 1 is 1MHz, the controller transmits the acquired current signal data to the base station data acquisition system 3 in a wireless transmission mode,
the GPS synchronous clock 2 is synchronized with a satellite GPS synchronous clock, and is a GPS synchronous clock that performs time calibration in consideration of a time difference of signal transmission according to a difference in position of each of the rogowski coils 1 from the base station 12.
The Rogowski coil 1 is an open-loop hollow flexible coil, and two ends of the Rogowski coil are butted and sleeved on the overhead line cable, so that the normal work of the overhead line cable is not influenced; compared with a mutual inductor, the Rogowski coil 1 has no problem of magnetic saturation, and the Rogowski coil 1 can also measure a high-frequency signal of an overhead line cable.
The GPS synchronous clock 2 is synchronous with the satellite GPS synchronous clock 2, and according to the difference of the distance between each Rogowski coil 1 and the base station 12, the time difference of signal transmission is considered to carry out time calibration, thereby avoiding misjudgment caused by the asynchronous clock of data transmission.
Further: the management station data analysis system is characterized by further comprising a fault alarm device 8 connected with the management station data analysis system 7, the fault alarm device 8 is connected with a GPS graphic display system 9, and the GPS graphic display system 9 comprises a plurality of GPS positioning devices installed on the overhead line cable.
The GPS graphic display system 9 can display the specific position and fault type of the fault overhead cable, and the operator on duty can accurately judge the position coordinate and phase sequence attribute of the fault cable according to graphic display, and take measures with pertinence.
Taking a certain section of overhead line as an example, the starting end and the tail end of the phase A of the overhead line cable are respectively fixed on the fixed point 10 of the overhead line cable, the starting end and the tail end of the phase A are respectively sleeved with Rogowski coils 1, and the Rogowski coils are respectively numbered K1 and K2 according to different positions of the Rogowski coils 1; the high-frequency current signals collected by the K1 and the K2 are respectively recorded as a function f (K1) and a function f (K2), and then are transmitted to the base station data collection system 3 as data in a wireless transmission mode; the base station data acquisition system 3 receives and records the data of the function f (K1) and the function f (K2) through the calibration of the GPS synchronous clock 2; the data analysis system 4 of the base station 12 performs data analysis on the data recorded by the base station data acquisition system 3 by adopting a wavelet analysis theory, which is simply described as follows: performing wavelet analysis on the difference between the two functions f (K1) and f (K2), namely performing wavelet analysis on the functions f (f (K1) -f (K2)); the overhead line cable is produced in a multi-strand twisting mode, when one strand of the overhead line cable breaks, a high-frequency signal function f (K1) collected at the starting end of the cable is different from a current high-frequency signal function f (K2) collected at the tail end of the cable, and the wavelet analysis result of the functions f (f (K1) -f (K2)) preliminarily judges that the health state of the cable changes; because enough allowance is reserved in the design of the cable, normal electric energy transmission cannot be influenced when one cable breaks, but the problems of temperature rise, resistance increase and the like occur at the broken part, so that potential safety hazards exist in the cable; the data analysis system 4 of the base station 12 wirelessly transmits the data with abnormal analysis results to the power grid data acquisition system 5; the power grid data acquisition system 5 receives and records the data transmitted by the data analysis system 4 of the base station 12; the power grid data analysis system 6 further performs data analysis on the data recorded by the power grid data acquisition system 5, performs fuzzy pattern recognition on the data and the fault type recorded in the fault database 7, and judges the fault type and the fault code; the fault alarm device 8 informs the operator on duty in an acousto-optic and electric mode according to the judgment result, displays the fault code and provides the fault code for the operator on duty; the GPS graphic display system 9 can display the position of the fault cable on a GPS graphic, and the operator on duty can accurately judge the position coordinate of the fault cable according to the graphic display and take measures with pertinence.
More specific description is: the Rogowski coil 1 is sleeved on an overhead line cable to collect a current high-frequency signal flowing through the cable as data, and wirelessly transmits the data to a base station 12 data collection system 3; the data needs to be calibrated by a GPS synchronous clock 2 in the process of wireless transmission; a data acquisition system 3 of a base station (12) receives and records data calibrated by a GPS synchronous clock 2; the base station data analysis system 4 analyzes according to the data recorded by the base station data acquisition system 3, judges whether the cable health state is normal or not, ignores the data with the judgment result of normal, and continues the process; the data with abnormal judgment result is wirelessly sent to a power grid data acquisition system 5; the power grid data analysis system 6 further analyzes the data recorded by the power grid data acquisition system 5; establishing a fault database 7 based on fault data obtained by performing fault simulation tests on the cable in different environments and data acquired when the cable breaks down in actual use environments; the power grid data analysis system 6 carries out complex wavelet theory analysis to obtain an analysis result, and then the fuzzy pattern recognition theory is used for matching with the fault type in the fault database 7 to obtain the fault type of the cable; the fault alarm device 8 gives a fault alarm and displays the specific position and fault type of the fault line on a GPS graphic display system 9.
More specific description is: the current signal acquisition is to acquire a current signal by using a Rogowski coil, wherein the current acquisition frequency is 1MHz, so that the acquired current component comprises a power frequency 50Hz normal current signal and a high-frequency current signal when the overhead line cable is healthy and in an unhealthy state; the current signal preprocessing is to perform signal preprocessing on the acquired current signals according to the rules of wavelet data analysis theory, remove the power frequency 50Hz low-frequency signals, obtain the high-frequency current signals acquired by K1 and K2, and respectively record the high-frequency current signals as a function f (K1) and a function f (K2); the signal difference analysis is to perform wavelet analysis on the difference between the two functions f (K1) and f (K2), namely, the function f (f (K1) -f (K2)) is subjected to wavelet analysis, high-frequency current signals f (K1) and f (K2) collected at the starting end and the tail end of the healthy overhead line cable are theoretically the same, and if the health of the overhead line cable between the starting end and the tail end is in a problem, the high-frequency current signals collected are subjected to wavelet analysis when the high-frequency current signals are theoretically different in the market; extracting signal extreme points, namely performing wavelet analysis on the difference of the high-frequency current signals, extracting the signal extreme points, and sequencing according to a time sequence to obtain accurate data of the distribution of the signal extreme points; the base station data analysis is that the base station data analysis system preliminarily judges whether the cable health state is normal according to the data distributed by the signal extreme points; if the judgment result is normal, continuing to acquire the current signal; the fault test simulation is to simulate various different faults possibly occurring on the overhead line cable through tests, the faults are accumulated according to the experience of workers, and the faults are continuously supplemented and accumulated in practical application; the method for collecting current signals, preprocessing the current signals, carrying out differential analysis on the signals and extracting the extreme points of the signals is completely the same as the method, and is not described repeatedly; establishing a fault database, namely defining a fault type according to the simulated fault test, defining a signal extreme point obtained by utilizing wavelet data analysis as fault data, storing the fault type and the fault data in the fault database in a one-to-one correspondence manner, and distributing a corresponding fault code to the fault type to facilitate identification; the fuzzy pattern recognition means that if the judgment result of the base station data analysis system is abnormal, fuzzy pattern recognition is carried out on the signal extreme point and the fault data in the fault database, and the similarity between the signal extreme point of the overhead line cable and the fault data is calculated according to a fuzzy recognition algorithm, wherein the similarity is a numerical value from 0 to 1; the fault type is identified according to the fuzzy pattern identification result, the closer the similarity is to 1, the higher the possibility that the overhead line cable is the fault type is, and otherwise, the closer the similarity is to 0, the lower the possibility that the overhead line cable is the fault type is.
Example two
Embodiment two provides an overhead cable health status monitoring method and a cable health status monitoring system, including all the steps of the method in embodiment one, which are not described herein again, and embodiment two provides a distribution diagram of an overhead line cable health status monitoring system, as shown in fig. 5, including the following,
taking a certain section of overhead line cable as an example, two ends of the overhead line cable are respectively erected on an overhead line iron tower 11 through fixing points 10, Rogowski coils 1 are respectively sleeved at two ends of the overhead line cable, and the Rogowski coils 1 are respectively numbered as K1 and K2 … KN according to different positions of the Rogowski coils 1;
the base station 12 is a basic substation, and the GPS synchronous clock 2, the base station data acquisition system 3 and the base station data analysis system 4 are arranged on the base station 12;
the management station 13 is a previous-level substation of the primary substation, and five units, namely an abnormal data acquisition system 5, a fault database 6, a management station data analysis system 7, a fault alarm device 8 and a step GPS graphic display system 9, are arranged on the management station 13.
Data acquisition and distribution are critical in the invention, because the overhead cable is outdoors and widely distributed, the overhead cable is erected at high altitude by using an overhead line iron tower 11, and if the health state of the cable is slightly observed by depending on electric power personnel, the observation cannot be realized; taking a certain section of overhead line as an example, the starting end and the tail end of the phase A of the overhead line cable are respectively fixed on the fixed point 10 of the overhead line cable, the starting end and the tail end of the phase A are respectively sleeved with Rogowski coils 1, and the Rogowski coils are respectively numbered as K1 and K2 … KN according to different positions of the Rogowski coils 1; for the convenience of management, a base station 11 is arranged in a basic substation of a power system, and a base station 12 comprises three units, namely a GPS synchronous clock 2, a base station data acquisition system and a base station data analysis system 4; arranging a system 13 at a primary unit substation on a basic level management station of an electric power system, wherein the system 13 comprises a power grid data acquisition system 5, a power grid data analysis system 6, a fault database, a fault alarm device 8 and a GPS graphic display system 9; the data acquisition distribution structure is a simple structural diagram, and the structural diagram can be more complex according to actual needs, and the range of the overhead line cable is wider, but the basic working principle is completely the same.
EXAMPLE III
The third embodiment provides a method for monitoring the health status of an overhead cable, which includes all the steps of the method in the first embodiment, and is not described herein again. The third embodiment provides a method for judging the position of a fault overhead line cable,
the method also comprises the following steps after the step 7,
and 8: a fault alarm is carried out, wherein for the event that the management station 13 judges that the overhead line cable has a fault, an attendant is notified in an acousto-optic and electric mode, and a fault code is displayed and provided for the attendant;
and step 9: and GPS graphic display, namely displaying the position of the fault overhead line cable on a GPS graphic, and enabling a person on duty to accurately judge the position coordinate of the fault overhead line cable according to the graphic display and take measures in a targeted manner.
As shown in fig. 6, which is a schematic diagram of a fault tree according to the present invention, the method for determining a cable position of a faulty overhead line includes the following steps: the management station 13 monitors that a fault occurs, and judges the base station 12 to which the fault overhead line cable belongs; the base station 12 determines the location of the faulty overhead line cable according to the number of the rogowski coil 1.
According to the fault tree principle, corresponding equipment is distributed step by step according to levels to complete corresponding functions in the process of monitoring the health state of the overhead line cable; the tree root corresponds to the system 13, the branches correspond to the base stations 12, the leaves correspond to the rogowski coils 1 on the fixed points 10 of the overhead line cables; the line fault distribution structure is a simple structural diagram, and the structural diagram can be more complex according to actual needs, and the range of the overhead line cable is wider, but the basic working principle is completely the same.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. The overhead cable current data primary analysis method is characterized by comprising the following steps,
step 41: preprocessing a current signal, namely removing power frequency 50Hz signals from the current signals at two positions on one phase of the overhead cable to obtain high-frequency current signals at the two positions, and respectively recording the high-frequency current signals as f (K1) and f (K2);
step 42: performing difference analysis on the signals, performing difference analysis on f (K1) and f (K2), if the signals are the same, monitoring the health state of the line cable to be normal, and if the signals are not the same, performing wavelet analysis on f (K1) -f (K2);
step 43: extracting the extreme difference points, extracting the extreme difference points of wavelet analysis in the step 42, and sequencing according to time to obtain the extreme difference point distribution waveform;
step 44: and (4) analyzing data, comparing the distribution waveform of the extreme points of the difference with a reference waveform, and judging whether the health state of the overhead line cable is normal or not.
2. An overhead cable health monitoring method using the overhead cable current data primary analysis method of claim 1, comprising the steps of:
step 1: current collection, at least two current collectors on the overhead cable distribute corresponding numbers and IP addresses, collect position current signals of the current collectors, and send the position current signals to a base station (12) in a wireless mode;
step 2: GPS synchronous clock calibration, according to the difference of the position of each current collector from a base station (12), considering the signal transmission time difference to carry out time calibration;
and step 3: base station data acquisition records, and the base station (12) receives and records data synchronously calibrated by a GPS clock;
and 4, step 4: analyzing base station data, wherein the base station (12) performs primary analysis on the current data of the overhead line cable according to the data recorded in the step 3 and the methods from the step 41 to the step 44, ignores normal data and transmits abnormal data to the management station (13) in a wireless transmission mode;
and 5: abnormal data acquisition, namely, receiving and recording abnormal data sent by a base station (12) by a management station (13);
step 6: establishing a fault database (6);
and 7: and (3) analyzing data of the management station, performing secondary analysis on the current data by the management station (13) according to the data recorded in the step (5) to obtain a difference extreme point, a characteristic parameter, a time sequence and a frequency, and then matching the result of the secondary analysis on the current data with the fault data in the fault database (6) by using fuzzy pattern recognition to obtain the fault type of the overhead line cable.
3. The overhead cable health monitoring method of claim 2, further comprising, after step 7,
and 8: the management station (13) judges the event of the overhead line cable fault, informs an operator on duty in an acousto-optic and electric mode, displays a fault code and provides the fault code for the operator on duty;
and step 9: and GPS graphic display, namely displaying the position of the fault overhead line cable on a GPS graphic, and enabling a person on duty to accurately judge the position coordinate of the fault overhead line cable according to the graphic display and take measures in a targeted manner.
4. Overhead cable health status monitoring method according to claim 2, characterized in that step 6 is in particular,
step 61: carrying out fault simulation tests on the overhead line cable in different environments, and recording fault types and corresponding fault data;
step 62: the method comprises the following steps of (1) recording fault types and corresponding fault data of faults of overhead line cables in actual use environments;
and step 63: and (6) storing the fault types and the fault data in the step 61 and the step 62 in a fault database (6) in a one-to-one correspondence manner, and distributing corresponding fault codes for the fault types.
5. The overhead cable health monitoring method of claim 2, wherein the secondary analysis of the current data in step 7 comprises the steps of:
step 71, performing difference analysis on the signals, and performing wavelet analysis on the difference between high-frequency current signals f (K1) and f (K2) of the abnormal data;
and step 72, extracting the extreme value point of the difference, the characteristic parameters, the time sequence and the frequency in the step 71.
6. The overhead cable health monitoring method of claim 2, wherein in step 7, the fuzzy pattern recognition comprises the steps of:
step 73, calculating the similarity between the result of the secondary analysis of the current data in the step 7 and the fault data in the step 6, and recording the similarity as a numerical value of 0-1;
and step 74, identifying the fault type and the fault possibility according to the numerical value of the similarity.
7. The overhead cable health monitoring method of claim 6, wherein the likelihood of the overhead line cable being the type of fault is higher as the value of the similarity is closer to 1, and the likelihood of the overhead line cable being the type of fault is lower as the similarity is closer to 0.
8. An overhead cable health status monitoring system to which the overhead cable health status monitoring method according to any one of claims 3 to 7 is applied, comprising
At least two current collectors arranged on the overhead line cable, wherein the current collectors comprise a controller, a Rogowski coil (1) and a GPS synchronous clock (2) which are connected with the controller,
the controller is connected with the base station data acquisition system (3), the base station data analysis system (4), the abnormal data acquisition system (5), the fault database (6) and the management station data analysis system (7) in sequence,
the two ends of the Rogowski coil (1) are butted and sleeved on an overhead line cable, the sampling frequency of the Rogowski coil (1) is 1MHz, a controller transmits acquired current signal data to the base station data acquisition system (3) in a wireless transmission mode,
the GPS synchronous clock (2) is synchronous with a satellite GPS synchronous clock, and is a GPS synchronous clock which carries out time calibration according to the difference of the position of each Rogowski coil (1) from a base station (12) and by considering the time difference of signal transmission.
9. The overhead cable health monitoring system of claim 8, wherein: the system is characterized by further comprising a fault alarm device (8) connected with the management station data analysis system (7), wherein the fault alarm device (8) is connected with a GPS (global positioning system) graphic display system (9), and the GPS graphic display system (9) comprises a plurality of GPS positioning devices installed on the overhead line cable.
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| CN110007196A (en) * | 2019-05-05 | 2019-07-12 | 华北电力大学（保定） | A method of on-line monitoring cable fault position |
| CN112485585A (en) * | 2020-10-26 | 2021-03-12 | 中铁第一勘察设计院集团有限公司 | Health state diagnosis system and method for cable through line |
| CN114545162A (en) * | 2022-02-15 | 2022-05-27 | 国网湖南省电力有限公司 | Distributed transmission line insulation performance online monitoring method |
| CN116466178A (en) * | 2023-03-03 | 2023-07-21 | 北京全路通信信号研究设计院集团有限公司 | High-frequency external network quality monitoring method, system and device |
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