Cable identification system and method

Abstract

The present invention relates to a cable identification system and method. The cable identification system includes an alternating current generator, a plurality of current identification devices, and an identification control and display device. The alternating current generator is used to output alternating current; the current identification device is used to detect the current of the cable, calculate the absolute integral value of the current within a set time length and output the corresponding current integral signal, and mark the cable; the identification control and display device is used to receive the current integral signal, identify the power-off cable and generate a marking control signal to send to the current identification device corresponding to the power-off cable. The cable identification method is: generate alternating current and connect to each cable, respectively detect the current of each cable and respectively calculate the absolute integral value of the current, and identify the power-off cable based on the absolute integral value of each current. The present invention improves the cable identification principle, can simplify the cable identification process, and improve the efficiency and accuracy of cable identification.

Description

Technical Field

[0001] The present invention relates to the technical field of cable construction, and in particular to a system and method capable of effectively distinguishing a power-off cable from a live cable in a high-voltage cable channel, that is, realizing automatic identification of the power-off cable. Background Art

[0002] During the high-voltage cable power outage cutting construction, since there are usually multiple live cables in the high-voltage cable channel, it is necessary to accurately distinguish between the power-off cables and the live cables.

[0003] At present, cable identification instruments are widely used for identification. The principle is: add a high-frequency pulse to the ground signal to the copper core of the cable at one end, and the copper core of the cable at the other end is grounded, so that the cable and the earth form a loop, and the magnitude and direction of the pulse current are detected at the detection point to realize the identification of the live cable. This method is usually more accurate, but accidents caused by cutting the live cable due to identification errors still occur from time to time. The reason is that the parameter setting of the current cable identification instrument is relatively complicated, and the measurement coil needs a specific direction to identify the current polarity. Due to the technical level limitations of the distribution network operators, misjudgments may occur in the following situations: 1. When there are fewer cables in the channel and the shielding layer of the live cable has a large backflow, the polarity of the measurement coil is set in the wrong direction, which is prone to misjudgment; 2. When the current of the source end is in the wrong direction, misjudgment will occur. At the same time, since the cable identification instrument needs to be used to identify all cables in the channel to distinguish between power-off cables and non-power-off cables, the operator who loads the high-frequency pulse at one end of the cable needs to communicate frequently with the operator at the detection operation point. When there are many cables in the channel, the process is cumbersome, and accidents caused by the operator not following the process are also common.

[0004] Therefore, a cable identification solution is needed that can simplify the workflow and improve identification efficiency and accuracy. Summary of the invention

[0005] The purpose of the present invention is to provide a cable identification system which simplifies the identification process and improves the identification efficiency and accuracy.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A cable identification system is used to identify a power-off cable among a plurality of cables, the cable identification system comprising:

[0008] An alternating current generator, the alternating current generator is used to output alternating current, and the alternating current generator is respectively connected between each of the cables and the ground;

[0009] A plurality of current identification devices, each of which is disposed in each of the cables, and is used to detect the current of the cable under the control of a detection control signal, calculate the absolute integral value of the current within a set time and output a corresponding current integral signal, upload the current integral signal, and mark the cable under the control of a marking control signal;

[0010] An identification control and display device, wherein the identification control and display device is communicatively connected with each of the current identification devices, and the identification control and display device is used to send the detection control signal to each of the current identification devices, receive the current integration signal uploaded by each of the current identification devices, identify the power-off cable based on each of the current integration signals, and generate the marking control signal and send it to the current identification device corresponding to the power-off cable.

[0011] Preferably, the current identification device comprises:

[0012] A detection end signal receiving unit, the detection end signal receiving unit is used to receive and forward the detection control signal and the marking control signal;

[0013] A current input unit, the current input unit is connected to the detection end signal receiving unit, the current input unit is used to receive the detection control signal, measure the differential value of the current in the cable with respect to time and upload a corresponding current differential signal;

[0014] A detection end data processing unit, the detection end data processing unit is connected to the current input unit, and the detection end data processing unit is used to calculate the current absolute value integral value within a set time length according to the current differential signal and upload the corresponding current integral signal;

[0015] A detection end signal sending unit, the detection end signal sending unit is connected to the detection end data processing unit, and the detection end signal sending unit is used to receive and upload the current integration signal;

[0016] A marking unit, the marking unit is connected to the detection end signal receiving unit, and the marking unit is used to receive the marking control signal and mark the cable.

[0017] Preferably, the current identification device further includes:

[0018] A timing unit, wherein the timing unit is respectively connected to the detection end signal receiving unit, the detection end signal sending unit, and the detection end data processing unit, and the timing unit is used to start timing after receiving the detection control signal so that the current input unit starts measuring when the set timing time is reached.

[0019] Preferably, the current input unit comprises a Rogowski coil sleeved on the outer circumference of the cable.

[0020] Preferably, the marking unit is a sound marking unit and / or a light marking unit capable of performing sound and / or light marking.

[0021] Preferably, the identification control and display device comprises:

[0022] an identification end signal sending unit, the identification end signal sending unit being used to send the detection control signal and the marking control signal to the current identification device;

[0023] an identification end signal receiving unit, the identification end signal receiving unit being used to receive and forward the current integration signal;

[0024] An identification end data processing unit, wherein the identification end data processing unit is respectively connected to the identification end signal sending unit and the identification end signal receiving unit, and the identification end data processing unit is used to output the detection control signal and the marking control signal to the identification end signal sending unit, receive the current integration signal forwarded by the identification end signal receiving unit, identify the power-off cable to obtain the cable identification result and generate the marking control signal.

[0025] Preferably, in the identification end data processing unit, the maximum value among the current absolute value integral values ​​is found, and if the maximum value is greater than the sum of the remaining current absolute value integral values, the cable where the current identification device that detects the maximum value is located is the power-off cable.

[0026] Preferably, the identification control and display device further includes:

[0027] A display unit is connected to the identification end signal processing unit, and is used to display the absolute value integral of the current detected by each current identification device and the cable identification result.

[0028] Preferably, the AC current generator is a high-frequency sinusoidal AC current generator.

[0029] Preferably, the current generator includes a power supply unit and an inverter unit connected to the power supply unit.

[0030] Preferably, the power supply unit comprises a lithium battery.

[0031] Preferably, the current generator further comprises a current measuring and display unit for detecting and displaying the magnitude of the output alternating current.

[0032] The present invention also provides a cable identification method that simplifies the identification process and improves identification efficiency and accuracy. The method is:

[0033] A cable identification method is used to identify a power-off cable among multiple cables. The cable identification method is as follows: an alternating current is generated and connected to one end of each of the cables, current detection is performed on each cable respectively, and the absolute value integral of the current within the corresponding set time length is calculated respectively, and the power-off cable is identified based on each of the current absolute value integral values; the method for identifying the power-off cable is as follows: a maximum value among the absolute value integral values ​​of the current is found, and if the maximum value is greater than the sum of the remaining absolute value integral values ​​of the current, the cable detecting the maximum value is the power-off cable.

[0034] Preferably, a high-frequency sinusoidal alternating current is generated and connected to each of the cables.

[0035] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: the present invention improves the cable identification principle, can simplify the cable identification process, and improve the cable identification efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Attached Figure 1 It is a principle block diagram of the cable identification system of the present invention.

[0037] Attached Figure 2 It is a schematic diagram of the connection of the AC current generator and the formed circulating current in the cable identification system of the present invention.

[0038] Attached Figure 3 It is a schematic diagram of the identification principle of the cable identification system of the present invention.

[0039] In the above figures: 11, cable; 12, cable head end; 13, cable end; 14, copper core; 15, measuring coil. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0041] Embodiment 1: There are multiple cables arranged in a cable channel. Before performing certain constructions, such as cable power-off cutting, it is necessary to first identify the power-off cables and the power-on cables. Figure 1 Cable identification system shown.

[0042] The cable identification system consists of three parts: AC current generator, current identification device and identification control and display device. The specific scheme is as follows:

[0043] The AC current generator is used to output AC current. The AC current generator is connected between each cable and the ground, as shown in the attached Figure 2As shown, the AC current generator has two power lines, one of which is connected to the copper core 14 of the cable 11 at the cable head end 12, and the other power line is connected to the grounding copper busbar, and the copper core 14 of the cable end 13 is grounded, so that a current loop can be formed between the cable 11 and the earth, as shown by the dotted line with arrows in the figure. The AC current generator preferably adopts a high-frequency sinusoidal AC current generator, which can output a high-frequency sinusoidal AC current and inject it into the copper core 14 of the cable 11. The current generator mainly includes a power supply unit and an inverter unit. The power supply unit includes a lithium battery, and the inverter unit is connected to the power supply unit, and the DC current output by the power supply voltage is inverted into AC current through the inverter unit. The current generator can also include a current measurement and display unit, which is used to detect and display the current size of the AC current output by the inverter unit.

[0044] Multiple current identification devices are provided, corresponding to the number of cables in the cable channel, and each cable is equipped with a current identification device, which is respectively provided on each cable 11 at the measuring point. The current identification device is used to detect the current of the cable 11 under the control of the detection control signal, calculate the absolute integral value of the current within the set time and output the corresponding current integral signal, upload the current integral signal, and mark the cable 11 under the control of the marking control signal. The current identification devices cooperate with each other and interact with the identification control and display device to realize the above functions, that is, to realize multi-loop current measurement and upload the data information to the identification control and display device after preliminary processing of the data.

[0045] The current identification device mainly includes a detection end signal receiving unit, a current input unit, a detection end data processing unit, a detection end signal sending unit, a marking unit and a timing unit.

[0046] Detection end signal receiving unit: The detection end signal receiving unit is used to receive and forward the detection control signal and the marking control signal. The detection control signal and the marking control signal come from the identification control and display device, that is, the detection end signal receiving unit can communicate with the identification control and display device, usually using wireless communication. After receiving the detection control signal or the marking control signal sent by the identification control and display device, the detection end signal receiving unit forwards it to other corresponding functional modules.

[0047] Current input unit: The current input unit is connected to the detection end signal receiving unit. The current input unit is used to receive the detection control signal, measure the differential value of the current in the cable with respect to time, and upload the corresponding current differential signal. After the detection end signal receiving unit sends the detection control signal to the current input unit, the current input unit starts to measure the current in the cable. The current input unit includes a measuring coil 15, such as a Rogowski coil, which is sleeved on the outer circumference of the cable to measure the AC current signal in the cable, and the measurement of the differential value of the current with respect to time is achieved through the Rogowski coil.

[0048] Detection end data processing unit: The detection end data processing unit is connected to the current input unit. The detection end data processing unit is used to calculate the absolute value integral of the current within the set time length according to the current differential signal and upload the corresponding current integral signal. After obtaining the differential value of the current with respect to time through the current input unit, the current value is obtained by integrating the current differential signal; after obtaining the AC current value, the absolute value of the current is further integrated according to time to obtain the absolute value integral of the current, and then the current integral signal is obtained. Therefore, the current identification device outputs the absolute value integral of the current (i.e., the effective value integral). In specific operations, the set time length can usually be set to 1 minute, and the detection end data processing unit outputs the absolute value integral of the current within 1 minute after the start of the measurement.

[0049] Detection end signal sending unit: The detection end signal sending unit is connected to the detection end data processing unit. The detection end signal sending unit is used to receive the current integration signal and upload the current integration signal to the identification control and display device. In addition, the detection end signal sending unit can also be used to send a self-test pass signal to the identification control and display device after the device is turned on, establish a communication connection, and send device fault information, etc.

[0050] Marking unit: The marking unit is connected to the detection end signal receiving unit. When the detection end signal receiving unit receives the marking control signal sent by the identification control and display device and forwards it to the marking unit, the marking unit is used to receive the marking control signal and mark the cable where it is located. The cable marked by the marking unit is the target cable, that is, the power-off cable. The marking unit is a sound marking unit and / or light marking unit that can perform sound and / or light marking. When it can perform sound and light marking at the same time, the marking unit can also be called a sound and light unit.

[0051] Timing unit: The timing unit is connected to the detection end signal receiving unit, the detection end signal sending unit, and the detection end data processing unit respectively. The timing unit is used to start timing after receiving the detection control signal so that the current input unit starts measuring when the set timing time is up. It is also used to cooperate with other current identification devices so that the current identification devices can send signals in turn to avoid mutual interference of signals, and can also realize synchronous start measurement.

[0052] The identification control and display device is connected to each current identification device in communication, thereby realizing interaction between it and the current identification device. The identification control and display device is used to send a detection control signal to each current identification device, receive a current integration signal uploaded by each current identification device, identify the power-off cable based on each current integration signal, and generate a marking control signal to send to the current identification device corresponding to the power-off cable. The identification control and display device includes an identification end signal sending unit, an identification end signal receiving unit, an identification end data processing unit, and a display unit.

[0053] Identification end signal sending unit: The identification end signal sending unit is in communication connection with the current identification device, and is used to send a detection control signal and a marking control signal to the current identification device, thereby controlling the current identification device to perform measurement and marking.

[0054] Identification end signal receiving unit: The identification end signal receiving unit is in communication connection with the current identification device, and is used to receive and forward the current integration signal, and can also receive the working status signal sent by the current identification device.

[0055] Identification end data processing unit: The identification end data processing unit is connected to the identification end signal sending unit and the identification end signal receiving unit respectively. The identification end data processing unit is used to output a detection control signal and a marking control signal to the identification end signal sending unit, receive the current integration signal forwarded by the identification end signal receiving unit, identify the power-off cable to obtain the cable identification result and generate a marking control signal. In the identification end data processing unit, the method for identifying the power-off cable based on the current integration signal uploaded by each current identification device is: find the maximum value among the absolute value integral values ​​of each current. If the maximum value is greater than the sum of the absolute value integral values ​​of the remaining currents, the cable where the current identification device that detects the maximum value is located is a power-off cable, and then generate a marking control signal and send it to the corresponding current identification device through the identification end signal sending unit to enable it to be marked.

[0056] Display unit: The display unit is connected to the identification end signal processing unit. The display unit is used to display the absolute value integral of the current detected by each current identification device and the cable identification result.

[0057] The method of using the above cable identification system is as follows:

[0058] 1. Arrange the above-mentioned AC current generator and current identification devices. All cables in the channel must be equipped with corresponding current identification devices. After the current identification device is turned on, it sends a self-test signal to the identification control and display device to ensure that the device is normal and the communication is unobstructed.

[0059] 2. The identification control and display device sends a measurement control signal to all current identification devices. After receiving the measurement control signal, each current identification device starts timing. According to the preset order, each current identification device feeds back a signal to the identification control and display device in turn (to prevent interference from simultaneous signal transmission). After a period of timing (for example, after 5 seconds), each current identification device starts current measurement synchronously. If a current identification device fails to start, the measurement can be stopped and replaced before starting the measurement again.

[0060] 3. The current identification device measures the differential value of the current to the time signal through the Rogowski coil, and obtains the current value by integrating the current differential signal. After obtaining the AC current value, the absolute value of the current is further integrated according to time to obtain the absolute value integral of the current, and the output current integral signal is obtained and uploaded to the identification control and display device.

[0061] The reasons why the current identification device adopts the above data measurement and processing scheme are: 1) Since all cables pass through the current identification device to measure the current synchronously, the integral value within a certain period of time is used as the measurement result, which can avoid the problem that the measurement results of each device cannot be compared and calculated due to the asynchronous time scale of the device. The current identification device does not need to strictly synchronize sampling during measurement, which reduces the difficulty of technical implementation and improves equipment reliability; 2) By integrating and accumulating the absolute value of the current within a certain period of time, the current can be accumulated, making the measurement values ​​of each cable under test more differentiated, improving the identification accuracy, and accurately identifying the situation where there are fewer cables in the cable channel or only two cables with similar paths, and the shielding layer of the running cable has a large backflow.

[0062] 4. After the measurement is completed, each current identification device sends a signal in turn according to the preset program and transmits the measurement results to the identification control and display device. After receiving the current integration signal sent by each current identification device, the identification control and display device identifies the size of each current absolute value integral value. When it is detected that the current absolute value integral value corresponding to a certain cable is the largest and it is greater than the sum of the current absolute value integral values ​​of all other cables, the cable is judged to be the target cable, that is, the power-off cable, and a marking control signal is sent to the current identification device on the target cable. After receiving the marking control signal, the current identification device sends an acoustic and optical phase signal to mark the cable.

[0063] The identification principle of the above cable identification system is shown in the attached Figure 3As shown: The high-frequency sinusoidal AC current generator emits a high-frequency sinusoidal AC current signal. The resulting current 1 will flow from the head end of the target cable through the copper core to the end grounding wire, and then to the earth. A portion of the current 2 will flow back to the high-frequency sinusoidal AC current generator through the earth. The other portions of current 3, current 4, current 5, ... current n will flow back to the high-frequency sinusoidal AC current generator through the end grounding wire of the target cable, the earth, the end grounding end of the remaining cable shielding layer, the head grounding end of the remaining cable shielding layer, and the grounding copper busbar. The current identification device measures current 1, current 3, current 4, current 5, ... current n respectively, while current 2 cannot be directly measured. (The gray dotted lines in the figure represent the stray ground capacitance current of each cable).

[0064] According to the node current method, we can get:

[0065] Vector sum: Current 1 = Current 2 + Current 3 + Current 4 + Current 5 + … + Current n.

[0066] If it is a pure resistance loop, the absolute value (effective value) can also get the above conclusion. Due to the shunting effect of the cable-to-ground capacitance effect, the absolute value (effective value) of currents 3, 4, 5...n... will be further reduced. In fact: |Current 1|>|Current 2|+|Current 3|+|Current 4|+|Current 5|+…+|Current n|, then: |Current 1|>|Current 3|+|Current 4|+|Current 5|+…+|Current n|, so the integral of the absolute value of current 1>the integral of the absolute value of current 3+the integral of the absolute value of current 4+the integral of the absolute value of current 5+…+the integral of the absolute value of current n. It can be seen that the above measurement scheme theoretically ensures the accuracy of the measurement.

[0067] Embodiment 2: A cable identification method for identifying a power-off cable among multiple cables, specifically: generating an alternating current and connecting one end of each cable, respectively detecting the current of each cable and respectively calculating the current absolute value integral within the corresponding set time length (measuring the differential value of the current with respect to the time signal, and obtaining the current value by integrating the current differential signal; after obtaining the alternating current value, further integrating the absolute value of the current according to time, thereby obtaining the current absolute value integral value), and identifying the power-off cable based on the absolute value integral values ​​of each current. The method for identifying the power-off cable is: finding the maximum value among the absolute value integral values ​​of each current, and if the maximum value is greater than the sum of the absolute value integral values ​​of the remaining currents, the cable with the maximum value detected is the power-off cable. In the above scheme, it is preferably implemented by generating a high-frequency sinusoidal alternating current and connecting each cable. The cable identification method is implemented by the cable identification system of embodiment 1.

[0068] Compared with the prior art, the present invention improves the cable identification principle and adopts the new scheme of the present application for cable identification. There is no possibility of identification error due to reverse polarity at the source end or reverse polarity at the measuring end, and the possibility of identification error due to polarity operation error by personnel is eliminated from the identification principle. At the same time, all devices are identified and measured synchronously, which greatly simplifies the measurement process. Fully automatic measurement is realized, and there is no need for manual judgment of the measurement results.

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A cable identification system for identifying a power-off cable among a plurality of cables, characterized in that: The cable identification system comprises: An alternating current generator, the alternating current generator is used to output alternating current, and the alternating current generator is respectively connected between each of the cables and the ground; A plurality of current identification devices, each of which is disposed on each of the cables, and is used to detect the current of the cable under the control of a detection control signal, calculate the absolute integral value of the current within a set time and output a corresponding current integral signal, upload the current integral signal, and mark the cable under the control of a marking control signal; An identification control and display device, wherein the identification control and display device is communicatively connected with each of the current identification devices, and is used to send the detection control signal to each of the current identification devices, receive the current integration signal uploaded by each of the current identification devices, identify the power-off cable based on each of the current integration signals, and generate the marking control signal and send it to the current identification device corresponding to the power-off cable; The method for identifying the power-off cable is: finding the maximum value among the absolute value integral values ​​of each current. If the maximum value is greater than the sum of the absolute value integral values ​​of the remaining currents, the cable with the maximum value detected is the power-off cable.

2. The cable identification system according to claim 1, characterized in that: The current identification device comprises: A detection end signal receiving unit, the detection end signal receiving unit is used to receive and forward the detection control signal and the marking control signal; A current input unit, the current input unit is connected to the detection end signal receiving unit, the current input unit is used to receive the detection control signal, measure the differential value of the current in the cable with respect to time and upload a corresponding current differential signal; A detection end data processing unit, the detection end data processing unit is connected to the current input unit, and the detection end data processing unit is used to calculate the current absolute value integral value within a set time length according to the current differential signal and upload the corresponding current integral signal; A detection end signal sending unit, the detection end signal sending unit is connected to the detection end data processing unit, and the detection end signal sending unit is used to receive and upload the current integration signal; A marking unit, the marking unit is connected to the detection end signal receiving unit, and the marking unit is used to receive the marking control signal and mark the cable.

3. The cable identification system according to claim 2, characterized in that: The current identification device also includes: A timing unit, wherein the timing unit is respectively connected to the detection end signal receiving unit, the detection end signal sending unit, and the detection end data processing unit, and the timing unit is used to start timing after receiving the detection control signal so that the current input unit starts measuring when the set timing time is reached.

4. The cable identification system according to claim 2, characterized in that: The current input unit includes a Rogowski coil sleeved on the outer circumference of the cable.

5. The cable identification system according to claim 2, characterized in that: The marking unit is a sound marking unit capable of sound marking and / or a light marking unit capable of light marking.

6. The cable identification system according to claim 1, characterized in that: The identification control and display device comprises: an identification end signal sending unit, the identification end signal sending unit being used to send the detection control signal and the marking control signal to the current identification device; an identification end signal receiving unit, the identification end signal receiving unit being used to receive and forward the current integration signal; An identification end data processing unit, wherein the identification end data processing unit is respectively connected to the identification end signal sending unit and the identification end signal receiving unit, and the identification end data processing unit is used to output the detection control signal and the marking control signal to the identification end signal sending unit, receive the current integration signal forwarded by the identification end signal receiving unit, identify the power-off cable to obtain the cable identification result and generate the marking control signal.

7. The cable identification system according to claim 6, characterized in that: The identification control and display device also includes: A display unit is connected to the identification end data processing unit, and is used to display the absolute value integral of the current detected by each current identification device and the cable identification result.

8. The cable identification system according to claim 1, characterized in that: The alternating current generator is a high-frequency sinusoidal alternating current generator.

9. The cable identification system according to claim 8, characterized in that: The high-frequency sinusoidal alternating current generator comprises a power supply unit and an inverter unit connected to the power supply unit.

10. The cable identification system according to claim 9, characterized in that: The power supply unit includes a lithium battery.

11. The cable identification system according to claim 9, characterized in that: The high-frequency sinusoidal alternating current generator also includes a current measuring and displaying unit for detecting and displaying the magnitude of the output alternating current.

12. A cable identification method, using the cable identification system according to any one of claims 1 to 11, for identifying a power-off cable among a plurality of cables, characterized in that: The cable identification method is: generate an alternating current and connect it to one end of each of the cables, perform current detection on each of the cables and calculate the absolute value integral of the current within the corresponding set time, and identify the power-outage cable based on the absolute value integral of each of the currents; the method for identifying the power-outage cable is: find the maximum value among the absolute value integrals of each of the currents, if the maximum value is greater than the sum of the remaining absolute value integrals of the currents, then the cable that detects the maximum value is the power-outage cable.

13. The cable identification method according to claim 12, characterized in that: A high frequency sinusoidal alternating current is generated and connected to each of the cables.

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