1. A coiled cable conductor quality measuring device is characterized by comprising a length measuring module for measuring the length of a coiled cable, a resistance measuring module for measuring the resistance of a conductor, a middle section conductor length measuring device and a central processing unit, wherein the device adopts a handheld structure, the resistance measuring module comprises a measuring circuit and two movable wiring terminals electrically connected with two ends of the measuring circuit, the wiring terminals are used for being electrically connected with two ends of a conductor section to be measured, the middle section conductor length measuring device is used for measuring the distance between the two wiring terminals, and the measuring circuit comprises a constant current source resistance measuring circuit and a double arm bridge resistance measuring circuit; the device also comprises a temperature sensor for measuring the temperature during the test; the central processing unit executes the following steps:

(1) the central processing unit controls the length measuring module to inject high-frequency low-voltage pulse to one end of the coiled cable, and the length of the cable is calculated according to pulse reflection time and pulse propagation speed; the central processing unit controls the resistance measuring module to measure the direct current resistance of the coiled cable through the constant current source resistance measuring circuit;

(2) calculating conductor resistance of the coiled cable per kilometer at standard temperature according to the cable length, the temperature during testing and the test resistance of the coiled cable, comparing the conductor resistance with a detection standard, and judging that the conductor quality of the coiled cable is qualified if the conductor resistance is lower than a standard required value; if the standard requirement value is higher than the standard requirement value, the next step is carried out;

(3) the central processing unit controls the resistance measuring module to measure the resistance of the end part of the cable through the double-arm bridge resistance measuring circuit, and the length of the end part of the cable is measured through the middle section conductor length measuring device;

(4) calculating the conductor resistance of the cable end part at each kilometer under the standard temperature according to the cable length, the temperature during testing and the testing resistance of the cable end part, comparing the conductor resistance with the detection standard, judging that the cable end part is unqualified if the conductor resistance is higher than a standard required value, and ending the test; if the quality is lower than the standard requirement value, the conductor quality at the end part of the cable is judged to be qualified, and the next step is carried out;

(5) the central processing unit controls the resistance measuring module to measure the resistance of the middle section of the cable through the double-arm bridge resistance measuring circuit, and the conductor length measuring device of the middle section measures the length of the middle section of the cable;

(6) and calculating the conductor resistance of the middle section of the cable at each kilometer at the standard temperature according to the cable length of the middle section of the cable, the temperature during testing and the test resistance, and comparing the conductor resistance with the detection standard to judge whether the conductor quality of the end part of the cable and the middle section of the cable is qualified or not.

2. The apparatus of claim 1, wherein: calculating the conductor resistance per kilometer at the standard temperature in the steps (2), (4) and (6), wherein the calculation formula is as follows:

in the formula R₂₀Represents the conductor resistance per kilometer at a standard temperature of 20℃, R_xDenotes the conductor resistance test result of the L-length cable at t DEG C, alpha₂₀The temperature coefficient of resistance of the conductor material of the cable at the standard temperature of 20 ℃ is shown, t represents the temperature at the time of measurement, and L represents the length of the cable.

3. The apparatus of claim 1, wherein: the middle section conductor length measuring device adopts a phase type laser range finder which is arranged at one of the wiring terminals, and a rotatable flat plate is connected at the other wiring terminal.

4. The apparatus of claim 1, wherein: the middle section conductor length measuring device adopts a measuring tape, the measuring tape is arranged on a certain wiring terminal, and a hook is arranged on the other wiring terminal and can be used for hanging the starting end of the measuring tape.

5. The apparatus of claim 1, wherein: the device also comprises a wireless communication module and a remote data processing platform, wherein the central processing unit sends the detection result to the remote data processing platform through the wireless communication module, and the data processing platform stores the detection result according to the detection standard.

6. The apparatus of claim 1, wherein: and the central processing unit is also used for carrying out data structuring processing on the detection result obtained by calculation to obtain detection data meeting the requirement of the remote data processing platform.

7. The apparatus of claim 6, wherein: the data structuring process is to output the detection data according to the following format: unique identification number, specification and model of the cable, and direct current resistance of the conductor at 20 ℃.

8. The apparatus of claim 1, wherein: the high-frequency low-voltage pulse comprises a plurality of measuring gears, and the measuring gears are automatically adjusted according to the length of the cable.

9. The apparatus of claim 1, wherein: the pulse propagation speed is obtained by selecting the same type of cable from the cables coiled in the whole batch and taking a short sample for calibration, the calibration pulse is a narrow pulse, and the length of the calibration cable is not less than 1.5 m.

10. The apparatus of claim 1, wherein: instead of the hand-held structure, rollers are provided at the bottom of the device.

Background

The power cable is one of the most important power grid materials for the development of the economic society. The quality event shows that quality problems such as 'poor-quality copper', 'core-lacking number', 'few cross section' in the middle section of the cable still occur occasionally, and the problem of the conductive quality of the middle section of the coiled power cable cannot be ignored.

Currently, cable conductor quality detection mainly employs an arrival sampling detection mode, namely: after the coiled power cable arrives, the cut end part is sent to a laboratory for carrying out conductor direct current resistance detection about 3 meters. Laboratory sampling test can only inspect the quality of the end conductor of the cable, and cannot inspect the quality of the middle section conductor of the coiled cable. If carry out laboratory sample presentation through intercepting interlude conductor and detect the quality of judging the interlude conductor, then the dish dress cable after the interception can only be useless to laboratory sample presentation detects and relates to processes such as sampling, sample presentation, system appearance, detection, seriously influences the timeliness of electric power cable material supply. Therefore, from the aspects of timeliness and cost, a new detection method and equipment are needed in the field of the material warehouse to realize the field rapid examination of the quality of the middle section conductor of the whole batch of coiled cables.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the problems, the invention provides a coiled cable conductor quality measuring device which can be used for quickly and comprehensively pre-screening and effectively detecting the quality of a conductor in the middle section of a coiled power cable on a warehouse site after the power cable is delivered.

The technical scheme is as follows: the technical scheme adopted by the invention is that the quality measuring device for the conductor of the coiled cable comprises a length measuring module for measuring the length of the coiled cable, a resistance measuring module for measuring the resistance of the conductor, a middle section conductor length measuring device and a central processing unit, wherein the device adopts a handheld structure which can be replaced by a bottom roller. The resistance measuring module comprises a measuring circuit and two movable wiring terminals electrically connected with two ends of the measuring circuit, the wiring terminals are used for being electrically connected with two ends of a conductor section to be measured, the conductor length measuring device at the middle section is used for measuring the distance between the two wiring terminals, and the measuring circuit comprises a constant current source resistance measuring circuit and a double-arm bridge resistance measuring circuit; the device also comprises a temperature sensor for measuring the temperature during the test; the central processing unit executes the following steps:

(1) the central processing unit controls the length measuring module to inject high-frequency low-voltage pulse to one end of the coiled cable, and the length of the cable is calculated according to pulse reflection time and pulse propagation speed; the central processing unit controls the resistance measuring module to measure the direct current resistance of the coiled cable through the constant current source resistance measuring circuit;

(2) calculating conductor resistance of the coiled cable per kilometer at standard temperature according to the cable length, the temperature during testing and the test resistance of the coiled cable, comparing the conductor resistance with a detection standard, and judging that the conductor quality of the coiled cable is qualified if the conductor resistance is lower than a standard required value; if the standard requirement value is higher than the standard requirement value, the next step is carried out;

(3) the central processing unit controls the resistance measuring module to measure the resistance of the end part of the cable through the double-arm bridge resistance measuring circuit, and the length of the end part of the cable is measured through the middle section conductor length measuring device;

(4) calculating the conductor resistance of the cable end part at each kilometer under the standard temperature according to the cable length, the temperature during testing and the testing resistance of the cable end part, comparing the conductor resistance with the detection standard, judging that the cable end part is unqualified if the conductor resistance is higher than a standard required value, and ending the test; if the quality is lower than the standard requirement value, the conductor quality at the end part of the cable is judged to be qualified, and the next step is carried out;

(5) the central processing unit controls the resistance measuring module to measure the resistance of the middle section of the cable through the double-arm bridge resistance measuring circuit, and the conductor length measuring device of the middle section measures the length of the middle section of the cable;

(6) and calculating the conductor resistance of the middle section of the cable at each kilometer at the standard temperature according to the cable length of the middle section of the cable, the temperature during testing and the test resistance, and comparing the conductor resistance with the detection standard to judge whether the conductor quality of the end part of the cable and the middle section of the cable is qualified or not.

Calculating the conductor resistance per kilometer at the standard temperature according to the cable length, the temperature during the test and the test resistance in the steps (2) and (4), wherein the calculation formula is as follows:

in the formula R₂₀Represents the conductor resistance per kilometer at a standard temperature of 20℃, R_xDenotes the conductor resistance test result of the L-length cable at t DEG C, alpha₂₀The temperature coefficient of resistance of the conductor material of the cable at the standard temperature of 20 ℃ is shown, t represents the temperature at the time of measurement, and L represents the length of the cable.

The middle section conductor length measuring device adopts a phase type laser range finder, and a rotatable flat plate is connected to one of the wiring terminals.

The middle section conductor length measuring device can also adopt a common tape measure, the tape measure is arranged on one wiring terminal, and a hook is arranged on the other wiring terminal and can be used for hanging the starting end of the tape measure.

The device also comprises a wireless communication module and a remote data processing platform, wherein the central processing unit sends the detection result to the remote data processing platform through the wireless communication module, and the data processing platform stores the detection result according to the detection standard.

And the central processing unit is also used for carrying out data structuring processing on the detection result obtained by calculation to obtain detection data meeting the requirement of the remote data processing platform. The data structuring process is to output the detection data according to the following format: unique identification number, specification and model of the cable, and direct current resistance of the conductor at 20 ℃.

The high-frequency low-voltage pulse comprises a plurality of measuring gears, and the measuring gears are automatically adjusted according to the length of the cable.

The pulse propagation speed is obtained by selecting the same type of cable from the cables coiled in the whole batch and taking a short sample for calibration, the calibration pulse is a narrow pulse, and the length of the calibration cable is not less than 1.5 m.

Has the advantages that: compared with the prior art, the invention has the following advantages: the invention provides a technical means for detecting the quality of the conductors at the middle section of the full-batch coiled cables, is suitable for quick and comprehensive pre-screening of the full-batch cable materials of the power grid after the materials are delivered, can realize effective inspection of the quality of the conductors at the middle section of the coiled cables, is complementary with the sampling detection of the cables in a laboratory, and can realize comprehensive control of the quality of the conductors of the materials of the power cables. The quality detection device for the conductor at the middle section of the coiled power cable has the following characteristics: the test operation is quick, the cable sheath peeling and sample preparation are not needed in the detection of the coiled cable, and the detection time of the single-coiled cable is less than 5 minutes; the detection is intelligent, the length of the coiled cable and the resistance test gear can be automatically adjusted, the direct-current resistance detection result of the conductor can be automatically converted into the resistance value at the standard temperature, and the resistance value can be intelligently researched and judged through the data processing platform. The device realizes the difficult problem that the quality of the conductor of the coiled cable is difficult to detect on site, and particularly provides an effective method for quickly checking the quality of the conductor at the middle section of the coiled cable.

Drawings

FIG. 1 is a schematic view of a detection process of the device for measuring the quality of a coiled cable conductor according to the present invention;

fig. 2 is a schematic structural diagram of a device for measuring the quality of a conductor of a coiled cable according to the invention.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

Fig. 2 is a schematic structural diagram of a quality measuring device for a coiled cable conductor according to the present invention. The device adopts portable structure convenience to remove and test at the scene, and portable structure can also be replaced with the bottom gyro wheel, more conveniently removes. The quality measuring device for the coiled cable conductor comprises a length measuring module, a resistance measuring module, a middle section conductor length measuring device, a central processing unit and the like.

The length measuring module comprises a pulse transmitting unit, a model receiving unit, a signal filtering unit, a signal shaping unit, a comparison circuit and a numerical control potentiometer unit. The pulse transmitting unit injects pulse signals with different pulse widths and different amplitudes into one end of the cable, after the pulse signals are transmitted to the other end along the cable, the pulse signals are reflected due to impedance mismatching, the reflected pulse signals are received through the model receiving unit and are subjected to signal filtering and waveform shaping treatment, the pulse signals are subjected to accurate measurement of pulse transmission time through the comparison circuit, and the threshold voltage of the comparison circuit is adjusted through the digital potentiometer.

Interlude conductor length measurement device can adopt phase type laser range finder, fixes phase type laser range finder in one of them binding post department, and another terminal department is connected with rotatable flat board, and the purpose is reflection laser signal, accomplishes the length measurement. When the length measuring device is used, a length of 2 meters is usually set, one connecting terminal is connected with one end of the sampling cable, then the sampling cable is straightened, the other connecting terminal is moved on the cable until the value on the distance measuring device reaches the set length, and then the other connecting terminal is connected to the point.

The middle section conductor length measuring device can also adopt a measuring tape, the measuring tape is arranged on a certain wiring terminal, the wiring terminal is fixed on the cable for a certain time, a hook is arranged on another wiring terminal, the starting end of the measuring tape can be hung, when the sampling part of the cable is completely straightened, another wiring terminal is moved on the cable, and the cable is fixed when the measuring tape reaches the set length.

The resistance measurement module comprises a constant current source measurement system and a double-arm bridge measurement system, which respectively correspond to the resistance detection measurement of the coiled cable and the resistance measurement of the end part and the middle section of the cable, and can select a resistance measurement mode according to the measurement requirement. The resistance measuring range of the constant current source measuring system is as follows: 0-5 omega, the resistance is divided into three gears according to the size of the measuring resistor, and the gears can be automatically adjusted; the resistance measuring range of the double-arm bridge measuring system is 10 mu omega-1 omega.

The central processing unit calculates the length measurement data and the resistance measurement data to obtain a detection result, and the length calculation formula is as follows:

and v is the calibrated wave velocity, t is the pulse propagation time, and detection data meeting the requirements of the data processing platform are obtained through data structuring processing.

The calculated conductor direct current resistance is given by the formula:

the measured resistance value was converted into a resistance value at a standard temperature (20 ℃). And carrying out structuralization processing on the calculation result to obtain structured data meeting the requirements of a data processing platform, wherein the structured data comprises: unique identification number, specification and model of the cable, direct current resistance of the conductor at 20 ℃ and the like.

The device also designs a wireless communication module which is used for being connected with a remote data processing platform to realize the safe transmission of the structured detection data between the detection equipment and the platform.

Full batch dish dress cable interlude conductor resistance rapid survey device has characteristics such as measurement accuracy height, detection intelligence, is applicable to the quick quality of full batch cable goods and materials in warehouse after arriving the goods and screens in advance.

Fig. 1 is a schematic view of a detection process of the quality measuring device for a coiled cable conductor according to the present invention. The specific implementation scheme is as follows:

s1: measuring direct current resistance and length of a coiled cable conductor: injecting high-frequency low-voltage pulse into one end of the coiled cable to obtain pulse reflection time, setting the pulse propagation speed of the full batch of coiled cables, and calculating to obtain the length of the cable.

According to the type and the length of the cable, the high-frequency low-voltage pulse is automatically adjusted according to the five-gear pulse widths of 5ns, 100ns, 500ns, 2 mu s and 5 mu s for testing, and the longer the cable length is, the larger the pulse width is.

The pulse propagation speed can be calibrated by intercepting the same batch of cables with the same model, the calibration high-frequency pulse width is 5 ns-100 ns, the calibration cable length is 1.5-100 m, and the longer the calibration cable length is, the smaller the wave speed calibration result error is.

And (3) resistance measurement: the resistance measurement of the coiled power cable is based on a volt-resistance method, namely, the coiled power cable is connected in series to a constant current source circuit of a known high-precision measurement resistor, the voltage drop between the coiled cable and the known resistor is measured, and the resistance of the coiled cable can be obtained through voltage-resistance comparison. The resistance measurement of the short sample conductor in the middle section of the power cable is measured by a high-precision double-arm bridge, and the measurement error is not more than 0.5 percent of soil.

After calculating the direct current resistance of the conductor at the ambient temperature, converting the direct current resistance into the resistance at the standard temperature (20 ℃) by the following formula:

in the formula: r₂₀A conductor resistance per kilometer at 20 ℃ R_xResults of the conductor resistance test of L-length cables at t DEG C, alpha₂₀The temperature coefficient of resistance of the conductor material at 20 ℃, t is the measured conductor temperature, the temperature coefficient is obtained by an instrument temperature measuring module, and L is the length of the coiled cable obtained by a length test.

S2: and (3) detection data structuring processing: according to the data format requirement of the data processing platform, carrying out structural processing on the detection data to enable the detection data to be automatically identified by the data processing platform, wherein the structural data comprises: unique identification number, specification and model of the cable, direct current resistance of the conductor at 20 ℃ and the like.

The structured detection data is transmitted to the data processing platform through wireless communication.

S3: intelligent study and judgment of detection data: after the structured data are transmitted to the data processing platform, the platform automatically identifies the detection data, compares the detection data with the standard requirement value, intelligently studies and judges the data according to the detection standard, generates a qualified or unqualified detection conclusion of the disc-mounted power cable, and feeds the detection conclusion back to the measuring device through the wireless communication module.

The data processing platform comprises a cable detection standard database, and the detection standard can be updated.

S4: re-testing the conductor resistance of the end part and the middle section of the cable: if the direct current resistance of the whole section of the conductor of the cable is unqualified, sampling at the end part of the cable, and measuring the conductor resistance of the middle section of the cable by a double-arm bridge method; and if the end part detection result is qualified, re-testing the short sample of the middle section of the coiled cable. When the quality of the end part or middle section conductor is measured, the cable is not required to be stripped and a sample is prepared, and a section of length of the sample is taken.

The sampling principle of the middle section of the cable is as follows: the distance between the sampling position and the end part of the cable is not less than 50m, and the sampling length is 1.5-3 m.

S5: cable interlude detected data intelligence is studied and judged: the cable end and middle section conductor resistance measurement data are subjected to structured processing and transmitted to a data processing platform, the platform is intelligently researched and judged, and a measurement result is obtained.