CN206420992U - A kind of offline inspection positioner of high-tension cable potential problems - Google Patents
A kind of offline inspection positioner of high-tension cable potential problems Download PDFInfo
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Abstract
The utility model discloses a kind of offline inspection positioner of high-tension cable potential problems, including：Single-chip microcomputer, signal generating module, signal amplification module, transformer, calibration detection module, sampling trigger signal module, cable under test, echo detecting circuit, data acquisition module, Data Analysis Services module and light-coupled isolation module, single-chip microcomputer, signal generating module, signal amplification module and transformer are sequentially connected；Transformer includes primary side and first and second primary side, and primary side is connected with signal amplification module, calibration detection module；First primary side is connected with cable under test, and cable is connected with echo detecting circuit, and echo detecting circuit, data acquisition module, Data Analysis Services module and light-coupled isolation module are sequentially connected, and light-coupled isolation module is connected to single-chip microcomputer；Second subprime side is connected with sampling trigger signal module, and sampling trigger signal module is connected with Data Analysis Services module；Light-coupled isolation module is located between single-chip microcomputer and Data Analysis Services module.
Description
Technical Field
The utility model relates to a cable testing field especially relates to a high tension cable potential problem's off-line detection positioner based on travelling wave method, safe convenient.
Background
In recent years, power grids at home and abroad are rapidly developed, a large amount of power cables are put into the construction of urban power grids, and the usage amount is increased year by year. With the continuous increase of the power load of the power grid, the failure rate of the cable is greatly increased, and great economic loss is caused. In order to ensure the reliable operation of the power cable and guarantee the safety of a power grid, the detection technology of the cable becomes a research hotspot of experts at home and abroad. At present, the common detection mode for high-voltage cables is as follows: before commissioning or periodically powering off the running high-voltage cable, and carrying out off-line detection.
Currently, the pulse current method is widely used in an offline detection method of a power cable. The basic principle is that an alternating current experimental power supply is used for pressurizing a cable to a certain voltage level, partial discharge can occur at the defect position of cable insulation, instantaneous voltage change can occur at two ends of the cable, pulse current is generated in a loop through a coupling circuit at the moment, and pulse voltage generated by the pulse current flowing through detection impedance is collected, amplified and displayed to measure the basic quantity of the partial discharge. The position is calculated by using the time difference generated by the forward and backward propagation of the pulse. However, the charging test of the cable needs high voltage and long time, and the charging system comprises a plurality of devices, such as a generator, a high-voltage transformer, a coupling capacitor and a high-voltage connecting cable, when the charging system is used for field detection. Meanwhile, the equipment is inconvenient to transport and is not beneficial to off-line detection under the field condition. And the pulse generated by the method is actually damped oscillation, when the potential defect point is close to the test point, the reflected pulse and the incident pulse are mixed due to the over-short pulse propagation path, so that the observation is not easy, the time difference between the incident pulse and the reflected pulse cannot be accurately obtained, and the positioning failure is caused. In addition, the method calculates the time difference by observing the oscilloscope, the error is very large, and the result is very inaccurate.
The oscillatory wave method replaces the traditional alternating current experimental power supply in the pulse current method through the passive resonance technology, so that the volume and the weight of the system are obviously reduced. On the basis of charging the cable by using direct current and finishing charging, a damping oscillation voltage wave is formed by a built-in high-voltage reactor, a high-voltage real-time solid-state switch and the test cable, and a discharge signal of a potential defect position of the cable is excited. Because the basic principle of the method is approximately the same as that of a pulse current method, the problem that the potential defect point cannot be accurately positioned when being close to the test point also exists. And still need to carry oscillograph equipment etc. in order to observe discharge signal and record data, it is troublesome. In addition, the method needs high-voltage charging, potential safety hazards exist for operators, secondary damage can be caused to cables with discharging sources, and damage to the cables is large.
Based on the above problems, there is a need in the art for a safe and convenient offline detection and positioning method and device for potential problems of high-voltage cables.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model provides a high tension cable potential problem's off-line detection positioning method and device safe convenient based on travelling wave method.
The utility model provides an above-mentioned technical problem's technical scheme as follows:
an off-line detection and positioning method for potential problems of a high-voltage cable comprises the following steps:
1) controlling a DDS signal generator to generate a sinusoidal signal for detecting a cable to be detected by a singlechip;
2) the sinusoidal signal is amplified through a signal amplification module;
3) the amplified sinusoidal signal is coupled to an echo detection circuit connected to a cable to be detected through a transformer;
4) sampling voltage at a detection end of the echo detection circuit by a data acquisition module;
5) the data analysis processing module reads the sampled waveform data and analyzes and processes the waveform data;
6) detecting and sampling the intact cable, and storing the sampled data of the waveform B into a storage unit of a data analysis processing module;
7) the data analysis processing module is used for obtaining the following data before carrying out data analysis processing on the sampling signals:
a) the propagation speed v of the sinusoidal signal in the cable to be tested;
b) the frequency f and the period T of the sinusoidal signal.
8) The data analysis processing module needs to complete the following steps during processing:
a) when a cable to be tested is detected, sampling data of a waveform A of two periods at a test point;
b) obtaining data of two periodic waveforms C reflected by the sine signal reaching the problem point according to the difference between the data of the waveform A obtained by detecting the cable to be detected and the data of the waveform B obtained by detecting the intact cable;
c) abscissa t of maximum point of waveform CiAnd the time delta t taken by the traveling wave to be transmitted to a potential problem point and then reflected backiThe relation of (A) is as follows:
d) the distance x of each problem point from the test point is calculated by the formula:
x＝vΔti/2
calculating;
9) when a cable to be measured with potential problems is detected, the single chip microcomputer collects the peak value of the voltage of the primary side of the transformer, compares the peak value with a corresponding value stored when the cable is detected to be intact, sends the obtained ratio to the data analysis processing module, and the data analysis processing module divides the sampling value of the current cable to be measured by the ratio so as to eliminate the influence of the aging, humidity and temperature of the circuit on the measurement.
On the basis of the technical scheme, the utility model discloses can also do following improvement.
Further, the method also comprises the following steps: and displaying the result obtained by analyzing and processing the data analysis and processing module on a display module.
Further, the signal amplification of the sinusoidal signal by the signal amplification module includes: the voltage is amplified by the voltage amplifier, and then the power is amplified by the power amplifier.
Because contain potential problem tested cable probably more than one potential problem point, can have a plurality of reflection waves, after the test point stack, waveform C has more than one maximum value point in a cycle, probably has a plurality of maximum value points, and the abscissa of ith maximum value point is ti, and the distance x of each potential problem point apart from the test end still can be through the formula x ═ v Δ tiAnd/2.
In practical applications, the frequency f of the sinusoidal signal should be fixed and f should be much smaller than the natural resonance frequency f of the echo detection circuit0(ii) a Typically, f may be chosen to be 50 kHz.
Sinusoidal signals are transmitted in a medium between a metal wire of a cable with potential problems and a metal shielding net, when the sinusoidal signals pass through potential problem points, waveforms are reflected, and pi phase mutation occurs during reflection; the finally sampled waveform data is signal waveform data obtained by superposing the signal coupled by the transformer and each reflected wave.
The utility model also provides an off-line detection positioner of high tension cable potential problem, include: the device comprises a single chip microcomputer, a signal generation module, a signal amplification module, a transformer, a calibration detection module, a sampling trigger signal module, a cable to be detected, an echo detection circuit, a data acquisition module, a data analysis processing module and an optical coupling isolation module, wherein a DDS signal generator connected to the single chip microcomputer is arranged in the signal generation module, and the single chip microcomputer controls the DDS signal generator to generate a sinusoidal signal; the DDS signal generator is connected with the signal amplification module through a resistor R1, and the signal amplification module is connected to the transformer; the transformer includes: the calibration detection module comprises a transformer primary side, a transformer first secondary side and a transformer second secondary side, wherein the transformer primary side is connected with the signal amplification module and the transformer primary side is also connected with the calibration detection module; the transformer first secondary side is connected with the cable to be tested, the cable to be tested is connected with the echo detection circuit, the data acquisition module, the data analysis processing module and the optical coupling isolation module are sequentially connected, and the optical coupling isolation module is connected to the single chip microcomputer; the second secondary side of the transformer is connected with the sampling trigger signal module, and the sampling trigger signal module is connected with the data analysis processing module; the optical coupling isolation module is arranged between the single chip microcomputer and the data analysis processing module.
On the basis of the technical scheme, the utility model discloses can also do following improvement.
The device further comprises a display module connected to the data analysis processing module and used for displaying the waveform and the calculated value sampled by the data analysis processing module.
Furthermore, a voltage amplifier and a power amplifier are sequentially arranged in the signal amplification module; the positive input end of the voltage amplifier is connected with the resistor R1, the negative input end of the voltage amplifier is grounded through a resistor R2, and a resistor R3 is connected between the negative input end and the output end of the voltage amplifier in parallel; the positive input end of the power amplifier is connected with the output end of the voltage amplifier, the negative input end of the power amplifier is in short circuit with the output end of the power amplifier, and the output end of the power amplifier is connected to the transformer.
Further, the calibration detection module includes: the transformer comprises resistors R6, R7 and R8, a detection operational amplifier and a detection circuit, wherein the resistors R6 and R7 are connected in series and then connected in parallel to the primary side of the transformer, the resistor R7 is grounded, the positive input end of the detection operational amplifier is connected between the resistors R6 and R7 through a resistor R8, the negative input end of the detection operational amplifier is in short circuit with the output end of the detection operational amplifier and is connected to the detection circuit, and the detection circuit is connected to the single chip microcomputer.
Further, the echo detection circuit includes: the high-voltage transformer comprises an inductor L1, a capacitor C1, resistors R4 and R5, a first secondary operational amplifier and a first secondary differential amplifier, wherein the inductor L1 and the capacitor C1 are respectively connected to the first secondary side of the transformer in parallel, the resistors R4 and R5 are connected in series and then connected to the first secondary side of the transformer in parallel, the positive input end of the first secondary operational amplifier is connected between the resistors R4 and R5, the negative input end of the first secondary operational amplifier is short-circuited with the output end of the first secondary operational amplifier, the first secondary differential amplifier is single-ended input and double-ended output, the positive input end of the first secondary operational amplifier is connected with the output end of the first secondary operational amplifier, and the double ends of the first secondary differential amplifier are output to the data acquisition.
Further, the sampling trigger signal module includes: the positive input end and the negative input end of the second secondary differential amplifier are connected to the second secondary side of the transformer, the output end of the second secondary differential amplifier is connected to the positive input end of the voltage comparator through resistors R9 and R10 which are connected in series, the negative terminal of the germanium diode is connected between the resistors R9 and R10, the resistors R11 and R12 are respectively connected to the positive input end and the negative input end of the voltage comparator, and the output end of the voltage comparator is connected to the data analysis processing module.
The utility model has the advantages that: the device can be used in a high-voltage cable production plant to detect the high-voltage cables produced by the high-voltage cable production plant, so that the cables with potential problems are prevented from being put into practical use to cause great economic loss; the method can also be used for checking the problems of the high-voltage cables, each section of the high-voltage cables which are just laid are detected, and waveform data obtained by detection are stored to be used as standard waveforms; if a problem occurs in the using process, detecting each section of high-voltage cable, and finding out the problem by comparing with each section of standard waveform.
Drawings
FIG. 1 is a system diagram of the offline inspection positioning device for potential problems of high voltage cables according to the present invention;
FIG. 2 is a block diagram of circuitry for potential problem detection and location of high voltage cables in one embodiment;
FIG. 3 shows three waveforms obtained from simulation;
in the drawings, the parts names represented by the respective reference numerals are listed as follows:
100. a single chip microcomputer; 200. a signal generation module; 300. a signal amplification module; 301. a voltage amplifier; 302. a power amplifier; 400. a transformer; 401. a primary side of a transformer; 4011. calibrating the detection module; 402. a first secondary side of the transformer; 403. a second secondary side of the transformer; 4031. a sampling trigger signal module; 500. a cable to be tested; 600. an echo detection circuit; 700. a data acquisition module; 800. a data analysis processing module; 801. a display module; 900. an opto-coupler isolation module;
1-2, a DDS signal generator; 1-6, a second secondary differential amplifier; 1-7, a first secondary differential amplifier; 1-8, a voltage comparator; 1-13, a detection operational amplifier; 1-14, a first secondary operational amplifier; 1-18, a detector circuit.
Detailed Description
The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.
Referring to fig. 1 and fig. 2, fig. 1 is a system structure diagram of an offline detection positioning device for potential problems of a high-voltage cable according to the present invention, and fig. 2 is a circuit block diagram of detection positioning for potential problems of a high-voltage cable in an embodiment; the off-line detection positioning device comprises: the device comprises a singlechip 100, a signal generating module 200, a signal amplifying module 300, a transformer 400, a calibration detecting module 4011, a sampling trigger signal module 4031, a cable to be tested 500, an echo detecting circuit 600, a data collecting module 700, a data analyzing and processing module 800, a display module 801 and an optical coupling isolation module 900, wherein,
a DDS signal generator 1-2 connected to the single chip microcomputer 100 is arranged in the signal generating module 200, and the single chip microcomputer 100 controls the DDS signal generator 1-2 to generate a sinusoidal signal for detecting a high-voltage cable with a hidden danger problem; the single chip microcomputer 100 can adopt an STC12C5a60S2 single chip microcomputer, the DDS signal generator 1-2 can adopt an AD9851, the single chip microcomputer 100 enables the DDS signal generator 1-2 to output the sinusoidal signal by writing a control word command into the DDS signal generator 1-2, and the frequency of the sinusoidal signal can be changed by changing the written control word.
The DDS signal generator 1-2 is connected to the signal amplification module 300 through a resistor R1; the signal amplification module 300 is sequentially provided with a voltage amplifier 301 and a power amplifier 302; the positive input end of the voltage amplifier 301 is connected with the resistor R1, the negative input end is grounded through a resistor R2, and a resistor R3 is connected in parallel between the negative input end and the output end of the voltage amplifier 301; the positive input end of the power amplifier 302 is connected with the output end of the voltage amplifier 301, and the negative input end of the power amplifier 302 is short-circuited with the output end thereof; therefore, the sinusoidal signal generated by the DDS signal generator 1-2 is subjected to voltage amplification through a voltage amplifier, and then is subjected to power amplification through a power amplifier; the voltage amplifier 301 can be LMH6629, the voltage of a power supply can reach +/-15V, and the function of the voltage amplifier is to amplify the sinusoidal signal output by the DDS signal generator 1-2, so that the voltage of the sinusoidal signal meets the requirement; in practical application, the amplification factor of the voltage can be adjusted by setting the resistance values of the resistors R2 and R3; the OPA2604 can be selected as the power amplifier 302, the output current can reach 350mA, and the function is to amplify the power of the sinusoidal signal from the voltage amplifier 301, so that the signal can meet the power requirement of the echo detection circuit.
The output of the power amplifier 302 is connected to the transformer 400, the transformer 400 comprising: a transformer primary side 401, a transformer first secondary side 402, and a transformer second secondary side 403, wherein,
a first end of the transformer primary side 401 is connected with an output end of the power amplifier 302, and a second end of the transformer primary side 401 is directly grounded;
the primary side 401 of the transformer is connected with the calibration detection module 4011, and the calibration detection module 4011 includes: resistors R6, R7 and R8, a detection operational amplifier 1-13 and a detection circuit 1-18, wherein the resistors R6 and R7 are connected in series and then connected in parallel to the primary side of the transformer, the resistor R7 is grounded, the positive input end of the detection operational amplifier 1-13 is connected between the resistors R6 and R7 through a resistor R8, the negative input end of the detection operational amplifier 1-13 is in short circuit with the output end of the detection operational amplifier and is connected to the detection circuit 1-18, and the detection circuit 1-18 is connected to the single chip microcomputer 100;
due to the influence of temperature and the like, the parameters of the device can slightly change and need to be calibrated; the primary side of the transformer is connected with two large resistors R6 and R7 in parallel, and the existence of the two large resistors does not affect the measurement; when the cable is detected completely, voltage signals at two ends of the resistor R7 are taken out, voltage peaks are obtained through a voltage follower consisting of the resistor R8 and the operational amplifiers 1-13 and a detection circuit 1-18, the voltage peaks are sent to an A/D conversion port of the single chip microcomputer 100 to be converted into digital quantities, and the digital quantities are stored in a memory of the single chip microcomputer;
similarly, when the cable with the potential problem is detected, the single chip microcomputer should record the peak value of the voltage signal from the resistor R7, compare the peak value with a corresponding value stored when the cable is detected to be intact, send the obtained ratio to the data analysis processing module 800 through optical coupling isolation, and the data analysis processing module 800 divides the sampling value of the cable with the potential problem by the ratio, so that the influence of temperature and the like on the measurement can be eliminated.
The transformer first secondary side 402 is connected with the cable 500 to be tested, the cable 500 to be tested is connected with the echo detection circuit 600, the data acquisition module 700, the data analysis processing module 800 and the optical coupling isolation module 900 are sequentially connected, and the optical coupling isolation module 900 is connected to the single chip microcomputer 100; wherein,
the echo detection circuit 600 includes: an inductor L1, a capacitor C1, resistors R4 and R5, first secondary operational amplifiers 1 to 14, and first secondary differential amplifiers 1 to 7, wherein the inductor L1 and the capacitor C1 are respectively connected in parallel to the first secondary side of the transformer, the resistors R4 and R5 are connected in series and then connected in parallel to the first secondary side of the transformer, a positive input terminal of the first secondary operational amplifier 1 to 14 is connected between the resistors R4 and R5, a negative input terminal of the first secondary operational amplifier 1 to 14 is short-circuited with an output terminal thereof, the first secondary differential amplifier 1 to 7 is a single-ended input and a double-ended output, a positive input terminal thereof is connected to the output terminal of the first secondary operational amplifier 1 to 14, and the double-ended output is connected to the data acquisition module 700;
in the echo detection circuit 600, the inductor L1 and the capacitor C1 can make the waveform of the sinusoidal signal for detection a relatively perfect sine wave; resistors R4 and R5 are sufficiently large resistors that their presence does not affect detection, for example, resistor R4 may be selected to be 100 megaohms and resistor R5 may be selected to be 100 kiloohms; the magnitude of the voltage coupled to the secondary side by the transformer 400 may be greater than 50V; the echo detection circuit 600 functions to: coupling the sinusoidal signal amplified by the power amplifier to a detection end of a cable to be detected, and generating a traveling wave in the cable to be detected so as to be sampled by a data acquisition module;
the first secondary operational amplifiers 1-14 can be selected from LM709, and the first secondary differential amplifiers 1-7 can be selected from AD 8132; the first secondary operational amplifier 1-14 follows the voltage across the resistor R5, and the first secondary differential amplifier 1-7 differentially amplifies the voltage signal output by the first secondary operational amplifier 1-14 for sampling by the data acquisition module 700; the power supply voltage supplied by the first secondary differential amplifier 1-7 is not too high, because the input voltage of the data acquisition module 700 is small, for example, the power supply voltage of the AD8132 is 2.7V;
the data acquisition module 700 is provided with a high-speed analog-to-digital (a/D) conversion chip, for example, an ADC08D1000 can be selected, and the signals output by the first secondary differential amplifiers 1 to 7 are sampled under the control of the data analysis processing module 800.
The sampling trigger signal module 4031 is connected to the second secondary side 403 of the transformer, and the sampling trigger signal module 4031 includes: a second secondary differential amplifier 1-6, resistors R9-R12, germanium diodes 1-20, and a voltage comparator 1-8, wherein the positive and negative input terminals of the second secondary differential amplifier 1-6 are connected to the second secondary side of the transformer, the output terminal is connected to the positive input terminal of the voltage comparator 1-8 through resistors R9 and R10 connected in series, the negative terminal of the germanium diodes 1-20 is connected between the resistors R9 and R10, the resistors R11 and R12 are respectively connected to the positive and negative input terminals of the voltage comparator 1-8, and the output terminal of the voltage comparator 1-8 is connected to the data analysis processing module 800;
the voltage comparators 1-8 can adopt an LM119, and the sampling trigger signal module 4031 extracts sampling trigger signals from two ends of the second secondary side 403 of the transformer and transmits the sampling trigger signals to the data analysis processing module 800; the second secondary differential amplifier 1-6 differentially amplifies the voltage from the second secondary side of the transformer, the germanium diode 1-20 is used for protecting the rear operational amplifier, so that the voltage of the negative half cycle of the output signal of the differential amplifier at the upper end of the germanium diode is not less than-0.2V, and the voltage comparator 1-8 is protected; the voltage comparator supplies power for the single power supply, and the power supply is the same as the data analysis processing module 800; when the output level of the second secondary differential amplifier 1-6 is higher than 0V, the voltage comparator 1-8 outputs a high level, and when the output level of the second secondary differential amplifier 1-6 is less than or equal to 0V, the voltage comparator 1-8 outputs 0V, thereby providing the data analysis processing module 800 with a sampling trigger signal.
Because the loads of the two secondary sides of the transformer are different, the phases are not completely the same, and the zero crossing point of the first secondary side is taken as the standard during measurement; when the cable is detected completely, the small time difference is recorded and stored; when a cable with potential hazards is actually measured, the time difference should be subtracted as a true sampling trigger signal when the sampling trigger signal from the output of the voltage comparator 1-8 is received.
The method for sampling the test point comprises the following steps: taking f as an example of 50kHz, one cycle is 20 uS; in order to improve the sampling accuracy, two periods are sampled by 1000 points on average; the interval between two adjacent coordinate points is 40nS, and the sampling process is as follows: these 1000 points are divided into 10 sampling rounds, each of which starts with a time provided by the voltage comparators 1-8. The first round samples 100 points 1, 11, 21, … … 991, the second round re-samples 100 points 2, 12, 22, 32, … … 992, and so on until the 10 th, 20 th, 30 th, … … 1000 th points are sampled. In this process, these 1000 points are sampled once. This process is repeated 1024 more times, adding the data obtained at each point during the sampling of the various processes. When a cable with a potential problem is actually detected, the cable is stored in the memory of the data analysis processing module 800, and data obtained when a good cable is detected is also stored initially.
A DSP digital signal processor is disposed in the data analysis processing module 800, for example, a TMS320F28 series digital signal processor can be adopted; the data analysis processing module 800 needs to control the data acquisition module 700 to perform sampling, including the start and end time of sampling, the sampling time interval, and the like; after receiving the sampling signal, analyzing the sampling signal and calculating the position of a potential problem point; when the data analysis processing module 800 receives the sampling trigger signal from the voltage comparator 1-8, the data acquisition module 700 is controlled to sample the test end of the cable 500 to be tested, and the obtained data is stored;
FIG. 3 is a diagram of three waveforms obtained from simulation; the waveform A is obtained by sampling the test end of the cable with the potential problem, the waveform B is obtained by sampling the test end when the cable is detected to be intact, and the waveform C is obtained by subtracting the amplitude of each coordinate point corresponding to the waveform B from the amplitude of each coordinate point corresponding to the waveform A and is equivalent to the waveform of a signal reflected by a sine wave when the sine wave passes through the potential problem point; the relationship between the abscissa ti of the maximum point of the waveform C and the time delta ti taken by the traveling wave to transmit to a potential problem point and then to return after being reflected is as follows:the distance x of each problem point from the test point is calculated by x ═ v Δ ti/2.
In addition, the data analysis processing module 800 is further connected to the display module 801, and is configured to display the waveform and the calculated value obtained by sampling by the data analysis processing module 800, display three waveforms, namely, the waveform of the sampling signal for the intact cable, and the waveform reflected by the potential problem point in a contrasting manner, and display the position of the potential problem point.
The utility model discloses an among the off-line measuring positioner, because singlechip 100 with data analysis processing module 800's power is different, needs to realize through the opto-coupler singlechip 100 with communication between the data analysis processing module 800, consequently, has set up between the two opto-coupler isolation module 900.
Therefore, the utility model generates the sine signal for detection by the signal generating module, and couples the signal to the detection circuit by the transformer after the voltage and power amplification is carried out on the sine signal by the voltage amplifying module and the power amplifying module; after the data analysis processing module controls the data acquisition module to sample the signal of the detection end of the cable to be detected, the data acquired by the data acquisition module is read, the data is analyzed and processed, and the waveform obtained by analysis and processing and the position of a potential problem point are displayed by the display module.
The utility model discloses can use at the high tension cable manufacturing plant, detect the high tension cable of high tension cable manufacturing plant production, prevent to take the cable of potential problem to drop into in the middle of the in-service use, cause great economic loss.
The utility model discloses it is used for the investigation of high tension cable problem to do. And detecting each section of the high-voltage cable which is just laid, and storing waveform data obtained by detection as a standard waveform. When a problem occurs in the using process, each section of high-voltage cable is detected, and the problem is found out by comparing with each section of standard waveform.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (6)
1. An off-line detection and positioning device for potential problems of a high-voltage cable, comprising: a singlechip, a signal generating module, a signal amplifying module, a transformer, a calibration detecting module, a sampling trigger signal module, a cable to be detected, an echo detecting circuit, a data collecting module, a data analyzing and processing module and an optical coupling isolating module, wherein,
a DDS signal generator connected to the single chip microcomputer is arranged in the signal generating module, and the single chip microcomputer controls the DDS signal generator to generate a sinusoidal signal;
the DDS signal generator is connected with the signal amplification module through a resistor R1, and the signal amplification module is connected to the transformer;
the transformer includes: a transformer primary side, a transformer first secondary side, and a transformer second secondary side, wherein,
the primary side of the transformer is connected with the signal amplification module, and the primary side of the transformer is also connected with the calibration detection module;
the transformer first secondary side is connected with the cable to be tested, the cable to be tested is connected with the echo detection circuit, the data acquisition module, the data analysis processing module and the optical coupling isolation module are sequentially connected, and the optical coupling isolation module is connected to the single chip microcomputer;
the second secondary side of the transformer is connected with the sampling trigger signal module, and the sampling trigger signal module is connected with the data analysis processing module;
the optical coupling isolation module is arranged between the single chip microcomputer and the data analysis processing module.
2. The off-line detection positioning device according to claim 1, further comprising a display module connected to the data analysis processing module for displaying the waveform sampled by the data analysis processing module and the calculated value.
3. The off-line detection positioning device according to claim 1 or 2, wherein a voltage amplifier and a power amplifier are sequentially arranged in the signal amplification module; the positive input end of the voltage amplifier is connected with the resistor R1, the negative input end of the voltage amplifier is grounded through a resistor R2, and a resistor R3 is connected between the negative input end and the output end of the voltage amplifier in parallel; the positive input end of the power amplifier is connected with the output end of the voltage amplifier, the negative input end of the power amplifier is in short circuit with the output end of the power amplifier, and the output end of the power amplifier is connected to the transformer.
4. The off-line inspection positioning device of claim 1 or 2, wherein the calibration inspection module comprises: the transformer comprises resistors R6, R7 and R8, a detection operational amplifier and a detection circuit, wherein the resistors R6 and R7 are connected in series and then connected in parallel to the primary side of the transformer, the resistor R7 is grounded, the positive input end of the detection operational amplifier is connected between the resistors R6 and R7 through a resistor R8, the negative input end of the detection operational amplifier is in short circuit with the output end of the detection operational amplifier and is connected to the detection circuit, and the detection circuit is connected to the single chip microcomputer.
5. The off-line detection positioning device according to claim 1 or 2, wherein the echo detection circuit comprises: the high-voltage transformer comprises an inductor L1, a capacitor C1, resistors R4 and R5, a first secondary operational amplifier and a first secondary differential amplifier, wherein the inductor L1 and the capacitor C1 are respectively connected to the first secondary side of the transformer in parallel, the resistors R4 and R5 are connected in series and then connected to the first secondary side of the transformer in parallel, the positive input end of the first secondary operational amplifier is connected between the resistors R4 and R5, the negative input end of the first secondary operational amplifier is short-circuited with the output end of the first secondary operational amplifier, the first secondary differential amplifier is single-ended input and double-ended output, the positive input end of the first secondary operational amplifier is connected with the output end of the first secondary operational amplifier, and the double ends of the first secondary differential amplifier are output to the data acquisition.
6. The off-line detection positioning device according to claim 1 or 2, wherein the sampling trigger signal module comprises: the positive input end and the negative input end of the second secondary differential amplifier are connected to the second secondary side of the transformer, the output end of the second secondary differential amplifier is connected to the positive input end of the voltage comparator through resistors R9 and R10 which are connected in series, the negative terminal of the germanium diode is connected between the resistors R9 and R10, the resistors R11 and R12 are respectively connected to the positive input end and the negative input end of the voltage comparator, and the output end of the voltage comparator is connected to the data analysis processing module.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106771882A (en) * | 2017-01-23 | 2017-05-31 | 鲁东大学 | The offline inspection localization method and device of a kind of high-tension cable potential problems |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106771882A (en) * | 2017-01-23 | 2017-05-31 | 鲁东大学 | The offline inspection localization method and device of a kind of high-tension cable potential problems |
| CN106771882B (en) * | 2017-01-23 | 2023-09-12 | 鲁东大学 | Off-line detection positioning method and device for potential problems of high-voltage cable |
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