CN112611938A - Method and device for calculating signal propagation attenuation coefficient in cable off-line partial discharge detection - Google Patents
Method and device for calculating signal propagation attenuation coefficient in cable off-line partial discharge detection Download PDFInfo
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- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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Abstract
The invention discloses a method and a device for calculating a signal propagation attenuation coefficient in cable off-line partial discharge detection, which expand a calibration link in the off-line partial discharge detection process by connecting 3-phase cables in series and injecting a simulation partial discharge signal, conveniently acquire the propagation attenuation condition of the injection simulation partial discharge signal after 1-6 times of the whole field of the cable, obtain a characteristic rule curve of cable propagation attenuation by means of exponential curve fitting, reversely calculate the relation between the detection partial discharge amount of a test end and the apparent partial discharge amount of a partial discharge source, obtain the real apparent partial discharge amount of a partial discharge occurring position, and solve the problems of complex calculation and low detection efficiency in the prior art when the structure and material parameters of the test cable cannot be mastered under the field condition.
Description
Technical Field
The application relates to the field of power cable equipment state inspection and test, in particular to a method for calculating a signal propagation attenuation coefficient in cable off-line partial discharge detection, and also relates to a device for calculating the signal propagation attenuation coefficient in cable off-line partial discharge detection.
Background
At present, off-line detection test technologies such as oscillatory wave partial discharge and ultra-low frequency partial discharge in state detection of a power distribution network cable line are widely applied, but a quota threshold is mainly used in related partial discharge evaluation criteria, but attenuation influence of partial discharge propagation characteristics on detected apparent partial discharge amount is not considered in common off-line partial discharge detection equipment, state evaluation is simply carried out according to a single criterion, and obviously, defects far away from a detection end cannot be reliably evaluated.
Disclosure of Invention
The application provides a method and a device for calculating a signal propagation attenuation coefficient in cable off-line partial discharge detection, which solve the problems of complex calculation and low detection efficiency in the prior art.
The application provides a method for calculating a signal propagation attenuation coefficient in cable off-line partial discharge detection, which comprises the following steps:
the connection between the terminals at the two ends of the cable line to be tested and the high-voltage electrical connection and the ground wire of the switch cabinet and the ring main unit is released; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
connecting the conductor and the metal shield at the opposite ends of the phase A and the phase B to be tested, and injecting the simulated partial discharge calibration source from the space between the conductor of the cable at the test end and the metal shield to obtain a plurality of groups of reflected wave waveforms of the simulated partial discharge after 3 times and 4 times of full-length propagation attenuation of the cable;
connecting the conductor of the B-phase test end and the C-phase test end with the metal shield, and performing analog partial discharge injection on an analog partial discharge calibration source between the conductor of the test-end cable and the metal shield to obtain a plurality of groups of reflected wave waveforms of analog partial discharge after the analog partial discharge is propagated and attenuated by 5 times and 6 times of the total length of the cable;
obtaining a regular curve of the amplitude attenuation of the partial discharge signal of the cable by simulating the partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and simulating the partial discharge injection waveform;
when the off-line partial discharge detection is carried out on the cable to be detected, after a partial discharge signal is detected and positioned at a test end, the apparent partial discharge amount at the partial discharge position is obtained according to an attenuation rule curve corresponding to the positioning data of the signal.
Preferably, the analog partial discharge standard source is obtained by adopting an oscillating wave and ultra-low frequency partial discharge detection equipment configuration.
Preferably, the reflected wave waveform after 1 time of cable full length propagation attenuation is simulated in the partial discharge and is obtained by testing the injected signal at the opposite end.
Preferably, the method for obtaining the law curve of the amplitude attenuation of the cable partial discharge signal by simulating the partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1 to 6 times of the total length of the cable and simulating the partial discharge injection waveform comprises the following steps:
carrying out exponential function fitting on a partial discharge attenuation waveform obtained by passing a simulation partial discharge signal through 1-6 times of the total length of the cable and a simulation partial discharge injection waveform;
and fitting and solving the exponential function to obtain a regular curve of the amplitude attenuation of the cable partial discharge signal.
Preferably, obtaining the apparent partial discharge amount at the partial discharge occurrence position according to the positioning data of the signal and the attenuation law curve includes:
inquiring an attenuation rule curve according to the positioning data;
and reversely calculating the relation between the detected partial discharge quantity of the test end and the apparent partial discharge quantity of the partial discharge source through the attenuation rule curve to obtain the apparent partial discharge quantity of the partial discharge position.
Preferably, after the step of obtaining the apparent play amount where the partial discharge occurs, the method further comprises:
the insulation state of the cable is evaluated based on the apparent amount of partial discharge where the partial discharge occurs.
This application provides a signal propagation attenuation coefficient's in detection computing device is put in cable off-line office simultaneously, includes:
the reflected wave waveform acquisition unit is used for removing the connection between the terminals at the two ends of the cable line to be tested and the high-voltage electrical connection and the ground wire of the switch cabinet and the ring main unit; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
the reflected wave waveform acquisition unit is used for connecting the conductor and the metal shield at the opposite ends of the phase A and the phase B to be tested, and injecting the simulation partial discharge calibration source between the conductor and the metal shield of the cable at the test end to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after 3 times and 4 times of total length propagation attenuation of the cable;
the reflected wave waveform acquisition unit is used for connecting the conductors of the B-phase test end and the C-phase test end with the metal shield, and injecting the simulation partial discharge calibration source between the conductor of the test-end cable and the metal shield to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after the simulation partial discharge is propagated and attenuated by 5 times and 6 times of the total length of the cable;
the device comprises a regular curve acquisition unit and a control unit, wherein the regular curve acquisition unit is used for acquiring a regular curve of the amplitude attenuation of the partial discharge signal of the cable through simulating the partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and simulating the partial discharge injection waveform;
and the apparent partial discharge acquisition unit is used for acquiring the apparent partial discharge at the partial discharge occurrence position according to an attenuation rule curve corresponding to the positioning data of the signal after the test end detects and positions the partial discharge signal when the offline partial discharge detection is carried out on the cable to be detected.
Preferably, the regular curve acquiring unit includes:
the fitting subunit performs exponential function fitting on a partial discharge attenuation waveform obtained by passing a simulation partial discharge signal through 1-6 times of the total length of the cable and the simulation partial discharge injection waveform;
and the curve acquisition subunit is used for solving the exponential function in a fitting way to obtain a regular curve of the amplitude attenuation of the cable partial discharge signal.
Preferably, the apparent partial discharge amount obtaining unit includes:
the inquiring subunit inquires an attenuation rule curve according to the positioning data;
and the apparent partial discharge acquisition subunit reversely calculates the relationship between the detected partial discharge at the test end and the apparent partial discharge of the partial discharge source through the attenuation rule curve to acquire the apparent partial discharge at the partial discharge occurrence position.
Preferably, the method further comprises the following steps:
and the evaluation unit is used for evaluating the insulation state of the cable according to the apparent partial discharge amount at the partial discharge occurrence position.
The method comprises the steps of expanding a checking link in the offline partial discharge detection process in a mode of connecting 3-phase cables in series and injecting a simulation partial discharge signal, conveniently obtaining the propagation attenuation condition of the injection simulation partial discharge signal after the cable passes through 1-6 times of the whole field, obtaining a cable propagation attenuation characteristic rule curve in a mode of exponential curve fitting, reversely calculating the relation between the detection partial discharge amount of a testing end and the apparent partial discharge amount of a partial discharge source, obtaining the real apparent partial discharge amount of the partial discharge occurring position, and solving the problems of complex calculation and low detection efficiency of the prior art when the structure and material parameters of the tested cable cannot be mastered under the field condition.
Drawings
Fig. 1 is a schematic flowchart of a method for calculating a signal propagation attenuation coefficient in a cable offline partial discharge detection according to an embodiment of the present application;
fig. 2 is a schematic diagram of a device for calculating a signal propagation attenuation coefficient in cable offline partial discharge detection according to an embodiment of the present application.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of implementation in many different ways than those herein set forth and of similar import by those skilled in the art without departing from the spirit of this application and is therefore not limited to the specific implementations disclosed below.
Fig. 1 is a schematic flowchart of a method for calculating a signal propagation attenuation coefficient in cable offline partial discharge detection, which is provided by the present application, and the method provided by the present application is described in detail below with reference to fig. 1.
The invention relates to a method for quickly calculating a signal propagation attenuation coefficient in off-line partial discharge detection of a distribution cable, which is suitable for quickly acquiring the propagation characteristics of the cable line by properly expanding the original signal calibration and instrument verification processes in the off-line partial discharge detection process of oscillatory waves, ultralow frequencies and the like of 10-35kV distribution cable lines, thereby more accurately estimating the apparent partial discharge amount at a partial discharge source and realizing lean estimation of a local defect state.
A method for quickly calculating signal propagation attenuation coefficient in off-line partial discharge detection of a distribution cable is characterized in that a line high-frequency signal loop is expanded on the basis of an original signal calibration and instrument verification process, partial discharge signal first wave and tail end reflected wave detection is simulated under multiple lengths, further propagation attenuation conditions of partial discharge signals in cables with multiple lengths are obtained, a partial discharge attenuation curve is drawn according to the standard condition of multipoint data, and finally when partial discharge occurs at any point in a cable line, the relation between the apparent partial discharge amount of a partial discharge source and the actual partial discharge amount detected by a detection end is obtained, and the implementation steps are as follows:
step S101, removing the high-voltage electrical connection and the ground wire connection between the terminals at the two ends of the cable line to be tested and the switch cabinet and the ring main unit; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
the method comprises the steps that a simulation partial discharge calibration source configured by oscillatory wave and ultralow frequency partial discharge detection equipment is adopted, simulation partial discharge injection is carried out between a test-end cable conductor and a metal shield from large to small, generally 100nC to 10pC, multiple groups of reflected wave waveforms of the simulation partial discharge after 2 times of cable full-length propagation attenuation can be obtained in the process, meanwhile, signals of the simulation partial discharge after 1 time of cable full-length propagation attenuation can be obtained through testing opposite-end injection signals, and the background noise condition of a line to be tested is observed in the process.
And S102, connecting the conductor and the metal shield at the opposite ends of the phase A and the phase B to be tested, and injecting the simulation partial discharge calibration source from the space between the conductor and the metal shield of the cable at the test end to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after 3 times and 4 times of full-length propagation attenuation of the cable.
Through the above process, a plurality of groups (different injection simulation partial discharge) of reflected wave waveforms after signals are propagated and attenuated by 2 times of the total length of the cable can be obtained, but attenuation curve characteristics cannot be fully described only according to 2 points, so that after step S101 is completed, a conductor and a metal shield at the opposite end of a test phase (taking phase a as an example) and another phase (taking phase B as an example) are connected, and a simulation partial discharge is injected at the connection position of the test end and A, B, so that partial discharge reflected wave waveforms after 3 times and 4 times of the total length of the cable can be obtained.
And step S103, connecting the conductors of the B-phase test end and the C-phase test end with the metal shield, and injecting the simulation partial discharge calibration source between the conductor of the test-end cable and the metal shield to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after the simulation partial discharge is propagated and attenuated by 5 times and 6 times of the total length of the cable.
And after the step S102 is completed, connecting the conductor of the B-phase and C-phase test ends with the metal shield, and injecting the simulated partial discharge calibration source between the conductor of the test end cable and the metal shield to obtain partial discharge reflection waveforms after 5 and 6 times of the total length of the cable.
And step S104, obtaining a regular curve of the amplitude attenuation of the cable partial discharge signal by simulating a partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and simulating an injection waveform of the partial discharge.
Partial discharge attenuation waveforms of the same analog partial discharge signal after passing through 1-6 times of the total length of the cable are obtained through the steps S101-S103, and a regular curve of the partial discharge signal amplitude attenuation in the cable can be solved through an exponential function fitting mode according to the head end injection waveforms and 3 groups of attenuation waveforms.
Step S105, when the off-line partial discharge detection is carried out on the cable to be detected, after the partial discharge signal is detected and positioned by the testing end, the apparent partial discharge amount at the partial discharge position is obtained according to the attenuation rule curve corresponding to the positioning data of the signal.
When off-line partial discharge detection is carried out, after a partial discharge signal is detected and positioned by a test end, an attenuation rule curve can be inquired according to positioning data of the signal, and the relation between the detected partial discharge quantity of the test end and the apparent partial discharge quantity of a partial discharge source can be reversely calculated, so that the real apparent partial discharge quantity of a partial discharge position is obtained, and the insulation state of the cable is accurately evaluated.
Corresponding to the method provided by the present application, the present application also provides a device 200 for calculating a signal propagation attenuation coefficient in cable offline partial discharge detection, as shown in fig. 2, including:
the reflected wave waveform obtaining unit 210 is used for removing the connection between the terminals at the two ends of the cable line to be tested and the high-voltage electrical connection and the ground wire of the switch cabinet and the ring main unit; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
a reflected wave waveform obtaining unit 220, which connects the conductor and the metal shield at the opposite ends of the phase a and the phase B to be tested, and injects the analog partial discharge calibration source from the space between the conductor and the metal shield of the cable at the test end to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after the transmission attenuation of the cable in full length is performed by 3 times and 4 times;
a reflected wave waveform obtaining unit 230, which connects the conductor of the phase B and the phase C test end with the metal shield, and performs analog partial discharge injection on the analog partial discharge calibration source between the test end cable conductor and the metal shield to obtain multiple groups of reflected wave waveforms of the analog partial discharge after 5 times and 6 times of cable total length propagation attenuation;
the regular curve obtaining unit 240 obtains a regular curve of the amplitude attenuation of the cable partial discharge signal by simulating a partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and the simulated partial discharge injection waveform;
the apparent partial discharge obtaining unit 250, when performing off-line partial discharge detection on the cable to be detected, obtains the apparent partial discharge at the partial discharge occurrence position according to the attenuation rule curve corresponding to the positioning data of the signal after the test end detects and positions the partial discharge signal.
Preferably, the regular curve acquiring unit includes:
the fitting subunit performs exponential function fitting on a partial discharge attenuation waveform obtained by passing a simulation partial discharge signal through 1-6 times of the total length of the cable and the simulation partial discharge injection waveform;
and the curve acquisition subunit is used for solving the exponential function in a fitting way to obtain a regular curve of the amplitude attenuation of the cable partial discharge signal.
Preferably, the apparent partial discharge amount obtaining unit includes:
the inquiring subunit inquires an attenuation rule curve according to the positioning data;
and the apparent partial discharge acquisition subunit reversely calculates the relationship between the detected partial discharge at the test end and the apparent partial discharge of the partial discharge source through the attenuation rule curve to acquire the apparent partial discharge at the partial discharge occurrence position.
Preferably, the method further comprises the following steps:
and the evaluation unit is used for evaluating the insulation state of the cable according to the apparent partial discharge amount at the partial discharge occurrence position.
The method comprises the steps of expanding a checking link in the offline partial discharge detection process in a mode of connecting 3-phase cables in series and injecting a simulation partial discharge signal, conveniently obtaining the propagation attenuation condition of the injection simulation partial discharge signal after the cable passes through 1-6 times of the whole field, obtaining a cable propagation attenuation characteristic rule curve in a mode of exponential curve fitting, reversely calculating the relation between the detection partial discharge amount of a testing end and the apparent partial discharge amount of a partial discharge source, obtaining the real apparent partial discharge amount of the partial discharge occurring position, and solving the problems of complex calculation and low detection efficiency of the prior art when the structure and material parameters of the tested cable cannot be mastered under the field condition.
Finally, it should be noted that: although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention.
Claims (10)
1. A method for calculating a signal propagation attenuation coefficient in cable off-line partial discharge detection is characterized by comprising the following steps:
the connection between the terminals at the two ends of the cable line to be tested and the high-voltage electrical connection and the ground wire of the switch cabinet and the ring main unit is released; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
connecting the conductor and the metal shield at the opposite ends of the phase A and the phase B to be tested, and injecting the simulated partial discharge calibration source from the space between the conductor of the cable at the test end and the metal shield to obtain a plurality of groups of reflected wave waveforms of the simulated partial discharge after 3 times and 4 times of full-length propagation attenuation of the cable;
connecting the conductor of the B-phase test end and the C-phase test end with the metal shield, and performing analog partial discharge injection on an analog partial discharge calibration source between the conductor of the test-end cable and the metal shield to obtain a plurality of groups of reflected wave waveforms of analog partial discharge after the analog partial discharge is propagated and attenuated by 5 times and 6 times of the total length of the cable;
obtaining a regular curve of the amplitude attenuation of the partial discharge signal of the cable by simulating the partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and simulating the partial discharge injection waveform;
when the off-line partial discharge detection is carried out on the cable to be detected, after a partial discharge signal is detected and positioned at a test end, the apparent partial discharge amount at the partial discharge position is obtained according to an attenuation rule curve corresponding to the positioning data of the signal.
2. The method of claim 1, wherein the analog partial discharge standard source is obtained by using oscillatory wave and ultra low frequency partial discharge detection device configurations.
3. The method of claim 1, wherein the simulation of the reflected wave form of the partial discharge after 1 time propagation attenuation over the full length of the cable is obtained by testing the injected signal at the opposite end.
4. The method of claim 1, wherein obtaining a regular curve of amplitude attenuation of the cable partial discharge signal by simulating a partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1 to 6 times of the total length of the cable and simulating a partial discharge injection waveform comprises:
carrying out exponential function fitting on a partial discharge attenuation waveform obtained by passing a simulation partial discharge signal through 1-6 times of the total length of the cable and a simulation partial discharge injection waveform;
and fitting and solving the exponential function to obtain a regular curve of the amplitude attenuation of the cable partial discharge signal.
5. The method of claim 1, wherein obtaining an apparent partial discharge amount at which a partial discharge occurs from the positioning data of the signal and the attenuation law curve comprises:
inquiring an attenuation rule curve according to the positioning data;
and reversely calculating the relation between the detected partial discharge quantity of the test end and the apparent partial discharge quantity of the partial discharge source through the attenuation rule curve to obtain the apparent partial discharge quantity of the partial discharge position.
6. The method of claim 1, further comprising, after the step of obtaining an apparent amount of partial discharge where the partial discharge occurs:
the insulation state of the cable is evaluated based on the apparent amount of partial discharge where the partial discharge occurs.
7. A device for calculating signal propagation attenuation coefficient in cable off-line partial discharge detection is characterized by comprising:
the reflected wave waveform acquisition unit is used for removing the connection between the terminals at the two ends of the cable line to be tested and the high-voltage electrical connection and the ground wire of the switch cabinet and the ring main unit; injecting analog partial discharge into a calibration source from a test end cable conductor and a metal shield to obtain a plurality of groups of reflected wave waveforms of the analog partial discharge after 2 times of cable full-length propagation attenuation and reflected wave waveforms of the analog partial discharge after 1 time of cable full-length propagation attenuation;
the reflected wave waveform acquisition unit is used for connecting the conductor and the metal shield at the opposite ends of the phase A and the phase B to be tested, and injecting the simulation partial discharge calibration source between the conductor and the metal shield of the cable at the test end to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after 3 times and 4 times of total length propagation attenuation of the cable;
the reflected wave waveform acquisition unit is used for connecting the conductors of the B-phase test end and the C-phase test end with the metal shield, and injecting the simulation partial discharge calibration source between the conductor of the test-end cable and the metal shield to obtain a plurality of groups of reflected wave waveforms of the simulation partial discharge after the simulation partial discharge is propagated and attenuated by 5 times and 6 times of the total length of the cable;
the device comprises a regular curve acquisition unit and a control unit, wherein the regular curve acquisition unit is used for acquiring a regular curve of the amplitude attenuation of the partial discharge signal of the cable through simulating the partial discharge attenuation waveform of the partial discharge signal after the partial discharge signal passes through 1-6 times of the total length of the cable and simulating the partial discharge injection waveform;
and the apparent partial discharge acquisition unit is used for acquiring the apparent partial discharge at the partial discharge occurrence position according to an attenuation rule curve corresponding to the positioning data of the signal after the test end detects and positions the partial discharge signal when the offline partial discharge detection is carried out on the cable to be detected.
8. The apparatus of claim 7, wherein the regularity curve obtaining unit comprises:
the fitting subunit performs exponential function fitting on a partial discharge attenuation waveform obtained by passing a simulation partial discharge signal through 1-6 times of the total length of the cable and the simulation partial discharge injection waveform;
and the curve acquisition subunit is used for solving the exponential function in a fitting way to obtain a regular curve of the amplitude attenuation of the cable partial discharge signal.
9. The apparatus of claim 7, wherein the apparent play amount obtaining unit comprises:
the inquiring subunit inquires an attenuation rule curve according to the positioning data;
and the apparent partial discharge acquisition subunit reversely calculates the relationship between the detected partial discharge at the test end and the apparent partial discharge of the partial discharge source through the attenuation rule curve to acquire the apparent partial discharge at the partial discharge occurrence position.
10. The apparatus of claim 7, further comprising:
and the evaluation unit is used for evaluating the insulation state of the cable according to the apparent partial discharge amount at the partial discharge occurrence position.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114720808A (en) * | 2022-06-09 | 2022-07-08 | 国网江西省电力有限公司电力科学研究院 | Nondestructive testing and positioning method for quality of conductor in middle section of cable |
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