CN114910250A - Method and device for identifying target optical cable from multiple optical cables - Google Patents
Method and device for identifying target optical cable from multiple optical cables Download PDFInfo
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- CN114910250A CN114910250A CN202210498220.6A CN202210498220A CN114910250A CN 114910250 A CN114910250 A CN 114910250A CN 202210498220 A CN202210498220 A CN 202210498220A CN 114910250 A CN114910250 A CN 114910250A
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- G01R31/60—Identification of wires in a multicore cable
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Abstract
The invention discloses a method for identifying a target optical cable from a plurality of optical cables, which comprises the following steps: A. connecting a signal transmitter to a metal reinforced core or a metal sheath at the near end of a target optical cable, and testing the grounding resistance by using a loop resistance testing module arranged on the signal transmitter; B. if the tested grounding resistance is infinite, a virtual grounding current loop is formed between the metal reinforcing core or the metal sheath in the optical cable and the ground in a capacitance mode, and a specific pulse signal is sent to the optical cable for detecting the specific pulse signal at the far end of the optical cable; C. using a signal receiver to perform pulse signal identification on the optical cable in the remote identification area; D. and identifying the optical cable with the specific waveform pulse signal as the target optical cable. The invention can carry out high-accuracy identification and detection on the target optical cable at higher efficiency, does not damage the optical cable and is more convenient and faster to operate.
Description
Technical Field
The invention relates to a method and a device for identifying a target optical cable from multiple optical cables, and belongs to the technical field of communication detection equipment.
Background
With the construction of all optical networks of large communication operators in China, the communication network transmission optical cable is large in scale, and a plurality of optical cables are usually arranged at optical cable bearing facility points of a machine room, an optical cross-connecting box, a communication pipe well or an optical cable pole and the like, and the number of the optical cables is from several to hundreds. Meanwhile, with the advance of the policy of 'co-construction sharing' of national communication infrastructure, the optical cables at the facilities may belong to different operators, which brings great difficulty to daily maintenance and construction of enterprises, especially because of the reasons of capacity expansion and network adjustment of optical networks, operations such as cutting, routing change and the like are required to be carried out on specific optical cables, the accuracy of the specific optical cables must be guaranteed by hundreds, otherwise, serious communication safety production liability accidents will be caused.
In the process of constructing and maintaining an optical cable communication line, construction units only pay attention to the fact that optical cables are connected and do not pay attention to problems of standard labeling of the optical cables and the like, or some optical cable hanging tags even fall off after a long time, so that operation and maintenance personnel cannot confirm the identities of the optical cables when maintaining the optical cables, particularly optical cables in co-constructed facilities and incoming optical cables in pipelines before offices, although the optical cables are usually only hundreds of meters, the identification difficulty is quite large due to the fact that the optical cables are large in number and very concentrated, and the damaged optical cables are difficult to distinguish when the optical cables are damaged, and huge challenges are brought to operation and maintenance of a communication network.
Optical cables constructed by operators are mainly divided into long-distance optical cables, local network optical cables and home-entry optical cables. At present, most communication optical cables running in a network mainly adopt metal reinforcing component optical cables, long-distance optical cables mainly adopt silicon core tube direct-buried optical cables as main optical cables, local network optical cables are mainly laid in pipelines in cities, pipelines and overhead ways are adopted in suburbs and towns, and overhead ways are mainly adopted in vast rural areas.
In the event of a missing or inaccurate cable hangtag, several methods of identifying the cable are currently available as follows:
1. the manual method comprises the following steps: identifying a specific optical cable by a method of groping and dragging the optical cable;
2. OTDR test method: manufacturing a fault point by artificially looping the optical cable, and identifying a specific optical cable by observing attenuation change of an OTDR test; this approach, which in practice poses a great risk to the optical network, is strictly forbidden;
3. the detection method of the optical cable general survey instrument comprises the following steps: the optical cable is knocked, and the knocking sound is intercepted by utilizing the optical interference principle and the sensing effect of the ordinary investigation instrument to identify the specific optical cable. In the method, on the point where a plurality of optical cables are intensively distributed, because the optical cables are mutually wound, the target optical cable can be correspondingly judged by mistake when a non-target optical cable is knocked, and the accuracy is low;
in addition, the identification of the specific optical cables adopts a one-to-one corresponding identification method, a large number of optical cables which are intensively distributed cannot be identified in groups, and the identification can be realized only by matching personnel at two ends, so that the efficiency is relatively low.
Disclosure of Invention
The invention aims to provide a method and a device for identifying a target optical cable from a plurality of optical cables. The high-accuracy identification and detection can be carried out on the target optical cable at high efficiency, the optical cable cannot be damaged, and the operation is more convenient and faster.
The technical scheme of the invention is as follows: a method for identifying a target optical cable from a plurality of optical cables is characterized by comprising the following steps:
A. connecting one end of the output end of the signal transmitter to the ground, connecting the other end of the output end of the signal transmitter to a metal reinforced core or a metal sheath at the near end of the target optical cable, and testing the grounding resistance by using a loop resistance testing module arranged on the signal transmitter;
B. if the tested grounding resistance is infinite, a virtual grounding current loop is formed between the metal reinforcing core or the metal sheath in the optical cable and the ground in a capacitance mode, and a specific pulse signal is sent to the optical cable for detecting the specific pulse signal at the far end of the optical cable;
C. using a signal receiver to perform pulse signal identification on the optical cable in the remote identification area;
D. and identifying the optical cable with the specific waveform pulse signal as the target optical cable.
In the method for identifying the target optical cable from the plurality of optical cables, in the step B, when the tested grounding resistance is lower than the set threshold, it is determined that the optical cables are continuous and the opposite end is grounded, and at this time, the detection of the target optical cable can be completed only by reducing the strength of the specific pulse signal and performing the steps C and D.
In the method for identifying the target optical cable from the plurality of optical cables, the pulse signal is a rectangular wave signal, and after the rectangular wave signal is fed into the target optical cable, the signal receiver located at the far end detects and subsequently processes and identifies the pulse current signal in the optical cable at the far end. The frequency selection range of the pulse signal is as follows: the pulse width selection range is between 10Hz and 100 KHz: the setting of the parameter can further improve the detection sensitivity and the anti-interference capability of the signal receiver between 10ms and 1 us.
In the method for identifying the target optical cable from the plurality of optical cables, the signal receiver receives the pulse signal through the current sensor, the current sensor is an open-type current transformer or a rogowski coil, all the optical cables are divided into a plurality of optical cables in one group during detection, the current sensor is sleeved into the plurality of optical cables in one group each time, and whether the target optical cable is in the optical cables is identified, so that the identification efficiency is improved.
In the foregoing method for identifying a target optical cable from a plurality of optical cables, the method for forming a virtual ground current loop in a capacitive manner between the metal reinforcing core or the metal sheath in the optical cable and the ground in step B includes two ways:
firstly, a virtual grounding current loop can be formed by distributed capacitance between a metal reinforced core or a metal sheath on a directly-buried or pipeline-laid optical cable and the ground;
second, a length of metal film tape is wrapped around the outer jacket of the distal end of the optical cable and grounded to form a virtual ground current loop.
In the foregoing method for identifying a target cable from a plurality of cables, if there is a splice in the middle of a cable segment, the following two methods can be adopted:
firstly, the optical cable from the near end to the front of the joint can be identified by forming a virtual ground current loop between a metal reinforced core or a metal sheath in the optical cable and the ground in a capacitance mode, and if the optical cable on the other side of the joint needs to be identified, a signal transmitter only needs to be connected to the other end of a target optical cable;
secondly, the optical cables at two ends of the joint box are wound with metal film adhesive tapes to form capacitors, and pulse signals are coupled to the metal reinforced core or the metal sheath of the optical cable at the rear end by the capacitors, so that the whole-process identification of the whole optical cable can be realized.
In the method for identifying the target optical cable from the plurality of optical cables, the pulse current received by the current sensor is filtered, amplified and AD converted, and then the DFT narrowband filtering calculation is performed in the form of digital signals, so that the signal-to-noise ratio of the signals is improved.
The target optical cable identification device for realizing the method is characterized by at least comprising the following steps:
the signal transmitter is used for detecting the grounding resistance after being connected with the metal reinforcing core or the metal sheath at the near end of the target optical cable and transmitting a pulse signal;
the signal receiver is used for detecting a pulse signal on a target optical cable;
the signal transmitter comprises a pulse signal generating module, a pulse power control module, an output conversion module, an output isolation transformer and a loop resistance testing module, wherein the pulse signal generating module is connected with the output conversion module sequentially through the pulse power control module and the output isolation transformer; and the output conversion module is also connected with a loop resistance test module.
In the target optical cable identification device, the signal receiver comprises a current sensor, a pre-amplification module, a signal processing module and a signal display module, and the current sensor is connected with the signal display module sequentially through the pre-amplification module and the signal processing module.
Compared with the prior art, the method simply and efficiently completes the task of identifying the target optical cable from a large number of optical cables at the centralized laying position of the optical cables, and has the following characteristics:
1. the metal component of the optical cable is used for transmitting and receiving signals, so that the target optical cable can be accurately and efficiently identified under the conditions of not occupying a fiber core, not damaging the structure of the optical cable and not changing the use environment of the existing optical cable;
2. the operation is carried out on the point positions of the target optical cable to be identified, and the target optical cable does not need to be arranged along a road, so that a large amount of time is saved;
3. the signal receiver can be accessed into a plurality of optical cables for identification at one time, and the identification efficiency is greatly improved.
4. Compared with the common optical cable general survey instrument, the method of the invention determines the target optical cable by using the specific pulse principle in the detection current loop, has strong anti-interference capability and does not have misjudgment.
5. Compared with the prior art, the method can complete the identification of the optical cable by only 1 person without 2 persons in cooperation, and improves the use efficiency of the personnel.
Drawings
FIG. 1 is a schematic diagram of the principles of the present invention;
FIG. 2 is an equivalent circuit diagram of the grounding of the metal reinforcing core or the metal sheath of the optical cable of the invention
FIG. 3 is a schematic structural diagram of the apparatus of the present invention;
FIG. 4 is a schematic diagram of a method for identifying a metallic core or a metallic sheath of a target optical cable segment in communication and grounded at an opposite end under any laying condition according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a method for identifying a joint in the middle of an optical cable segment in a direct-buried optical cable or a pipe-laid optical cable according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a method for identifying an aerial cable having a joint between cable segments according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a method for identifying a joint in a manhole in the middle of a cable segment for laying an aerial and pipeline hybrid cable according to an embodiment of the present invention;
fig. 8 is a schematic diagram illustrating a method for identifying aerial splices in intermediate frames of a cable segment in an aerial, duct-mixed cabling cable according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a signal receiver according to the present invention;
FIG. 10 is a schematic diagram of the emitter follower circuit of FIG. 9;
FIG. 11 is a schematic diagram of the low noise preamplifier circuit of FIG. 9;
FIG. 12 is a schematic diagram of the automatic gain control circuit of FIG. 9;
FIG. 13 is a schematic diagram of the structure of the syntropy amplifying circuit in FIG. 9;
FIG. 14 is a schematic diagram of the comparison circuit of FIG. 9;
fig. 15 is a schematic structural diagram of the low frequency phase detection circuit in fig. 9;
FIG. 16 is a schematic diagram of a signal transmitter of the present invention;
FIG. 17 is a schematic diagram of a pulse signal generating module shown in FIG. 16;
fig. 18 is a schematic diagram of a pulse power control module in fig. 16.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
In one embodiment, a method of identifying a target cable from a plurality of cables includes the steps of:
A. connecting one end of the output end of the signal transmitter to the ground, connecting the other end of the output end of the signal transmitter to a metal reinforced core or a metal sheath at the near end of the target optical cable, and testing the grounding resistance by using a loop resistance testing module arranged on the signal transmitter;
B. if the tested grounding resistance is infinite, a virtual grounding current loop is formed between the metal reinforcing core or the metal sheath in the optical cable and the ground in a capacitance mode, and a specific pulse signal is sent to the optical cable for detecting the specific pulse signal at the far end of the optical cable;
C. using a signal receiver to perform pulse signal identification on the optical cable in the remote identification area;
D. and identifying the optical cable with the specific waveform pulse signal as the target optical cable.
In the step B, when the tested ground resistance is lower than a set threshold (generally 30 kilo-ohms), it is determined that the optical cable is continuous and the opposite end is grounded, and at this time, the detection of the target optical cable can be completed only by reducing the strength of the specific pulse signal and performing the steps C and D.
Preferably, the pulse signal is a rectangular wave signal, and after the rectangular wave signal is fed into the target optical cable, the signal receiver at the far end detects and subsequently processes and identifies the pulse current signal in the optical cable at the far end. The current sensor identifies the pulse signals based on the mode that the sudden change of the front edge and the rear edge of the rectangular wave signals can induce pulse current, so that interference can be avoided, and the detection sensitivity can be improved. The detection principle of the current sensor is based on the impulse (current) response of a pulse signal, and the mathematical expression is as follows: i (t) ═ K ═ du (t)/d (t). The pulse signal cannot be detected on the non-target optical cable.
Further, under the test condition that the metal reinforced core or the metal sheath of the optical cable to be tested is grounded at the opposite end, the principle is shown in an equivalent circuit of FIG. 2, and then the grounding resistance R is 0 Very small because the distributed capacitance impedance is much larger than the opposite end ground resistance R 0 The pulse current mainly forms a loop by grounding the opposite end, and when the signal receiver moves from A to B on the target optical cable, the detected pulse signal waveform is a rectangular wave similar to an overshoot. Under the test condition that the opposite ends of the metal reinforced core or the metal sheath of the target optical cable are open, the principle is shown in an equivalent circuit of FIG. 2, and then the grounding resistance R 0 The pulse current is mainly formed by the impedance of the optical cable metal reinforced core or the metal sheath to the distributed capacitance of the ground, the current loop differentiates the pulse waveform, the distributed capacitance forming the detection loop becomes smaller and smaller as the signal receiver moves from A to B on the target optical cable, the pulse current detected by the signal receiver becomes smaller and smaller, the differential effect is more obvious, the detected pulse signal waveform gradually changes from a similar rectangular wave with overshoot into a comb wave, and the pulse amplitude also decreases until the detection sensitivity limit of the signal receiver.
As long as the opposite end of the whole optical cable section to be identified is directly buried or laid in a pipeline with the length larger than 20M, the target optical cable can be reliably identified by virtue of a virtual grounding loop formed by the optical cable metal reinforced core or the metal sheath to the ground distributed capacitor, so that most optical cable sections can be identified without performing additional processing on the target optical cable.
Furthermore, by means of the judgment of the pulse polarity, the identification of the same-route optical cable in the optical cable branching joint can be completed.
The signal receiver receives pulse signals through the current sensor, the current sensor is an open type current transformer or a Rogowski coil, all optical cables are divided into a plurality of optical cables during detection, the current sensor is sleeved into the plurality of optical cables at each time, and whether a target optical cable is located in the optical cables is identified, so that the identification efficiency is improved.
The method for forming a grounding current loop in the step B by utilizing the metal reinforcing core or the metal sheath in the optical cable and the ground in a capacitance mode comprises two modes:
firstly, a virtual grounding current loop can be formed by distributed capacitance between a metal reinforced core or a metal sheath on a directly-buried or pipeline-laid optical cable and the ground;
second, a length of metal film tape is wrapped around the outer jacket of the distal end of the optical cable and grounded to form a virtual ground current loop.
If there is a splice in the middle of a fiber optic cable segment, the following two methods can be used:
1. the optical cable from the near end to the front of the joint can be identified by utilizing a mode that a virtual ground current loop is formed between the metal reinforced core or the metal sheath in the optical cable and the ground in a capacitance mode, and if the optical cable on the other side of the joint needs to be identified, only the signal transmitter needs to be connected to the other end of the target optical cable.
2. The metal film adhesive tape is wound on the optical cables at the two ends of the joint box to form a capacitor, and the pulse signals are coupled to the metal reinforced core or the metal sheath of the optical cable at the rear end by the capacitor, so that the whole-process identification of the whole optical cable can be realized.
Pulse current received by the current sensor is filtered, amplified and AD converted, and then DFT narrow-band filtering calculation is carried out in a digital signal mode, so that the signal-to-noise ratio of signals is improved.
Since DFT can have the following convolution form
Where N denotes time, x (N) denotes an input signal, and x (k) denotes a DFT output signal.
For a given k, the output of the DFT is the value of the input signal x (N) at time N through a filter with impulse response exp (2 π kn/N). After the input signal passes through the 1024-point DFT, most of the noise can be filtered out, thereby improving the signal-to-noise ratio.
The structure of the target optical cable identification device is shown in fig. 3, and comprises:
the signal transmitter 1 is used for detecting the grounding resistance after being connected with a metal reinforced core or a metal sheath at the near end of a target optical cable and transmitting a pulse signal;
the signal receiver 2 is used for detecting a pulse signal on a target optical cable;
the signal transmitter 1 comprises a pulse signal generating module 11, wherein the pulse signal generating module 11 is connected to an output isolation transformer 14 through a pulse power control module 12 and is finally connected with an output conversion module 13; the output conversion module 13 is also connected with a loop resistance test module 15. The output isolation transformer 14 functions to vary the amplitude of the output pulse signal and also to isolate the meter ground from the earth ground when transmitting the signal. The loop resistance test module 15 is generally applicable to conventional resistance test circuits and is therefore not shown in the drawings.
The signal receiver 2 comprises a current sensor 21, and the current sensor 21 is connected with a signal display module 24 through a pre-amplification module 22 and a signal processing module 23 in sequence. The preamplification module 22 module comprises an emitter follower circuit 2201, a low-noise preamplification circuit 2202, an automatic gain control circuit 2203 and a homodromous proportion amplifying circuit 2204 which are connected in sequence, one output of the homodromous proportion amplifying circuit 2204 is connected to the signal processing module 23, the other output is connected with the signal processing module 23 through a comparison circuit 2205, the input end of the emitter follower circuit 2201 is connected with the current sensor 21 through a filter capacitor, the output end of the automatic gain control circuit 2203 is also connected with the signal processing module 23 through a low-frequency phase discrimination circuit 2206, and the signal processing module 23 can adopt an ATxmega singlechip.
The specific working principle is as follows: the amplitude of the signal coupled by the current sensor is weak, generally in mV magnitude, and after passing through the emitter follower circuit 2201, the signal is sent to the low-noise preamplifier circuit 2202 for amplification, and then sent to the automatic gain control circuit 2203 to increase the amplitude of the signal to 500mV for output, one path of the signal enters the low-frequency phase discrimination circuit 2206 for phase discrimination, and the other path of the signal enters the homodromous proportional amplification circuit 2204 for continuous amplification and then is sent to the high-speed a/D conversion channel of the signal processing module 23(ADC0 pin) for AD conversion.
The signal processing module 23(DAC1 pin) outputs a synchronous sampling (trigger) comparison signal to the comparison circuit 2205, which is compared with the input signal to generate a synchronous sampling signal, and the synchronous sampling signal is transmitted back to the signal processing module 23 to enable the signal processing module 23 to have a fixed period of start point determination function during the AD conversion of the input signal. The output signal of the signal processing module 23 (pin DAC 0) is fed back to the agc circuit 2203 to amplify the signal more accurately.
The specific using method of the invention comprises the following steps:
due to the diversity of the cable laying modes, the following description is made with reference to the accompanying drawings for the cable identification methods in some typical laying modes.
1. Under any laying condition, the middle of the metal reinforced core or the metal sheath of the optical cable section to be checked has no break point, the identification method of the opposite end grounding refers to fig. 4, all the optical cable metal reinforced cores and the metal sheath at the near end (A end) are disconnected from the grounding, one end of the signal generator is grounded, the other end of the signal generator is connected to the metal reinforced core or the metal sheath at the A end of the target optical cable, and the far end (B) of the optical cable is grounded. The loop resistance is tested by using the loop resistance detection function of the signal generator, and the loop resistance is generally less than 30K omega, which indicates that the metal member of the optical cable is continuous and the opposite end is grounded. At the moment, the pulse current mainly depends on the grounding resistance of the optical cable metal component to the earth to form a loop, and from the end A to any position between the end B, the signal receiver receives the pulse current signal on the target optical cable, and cannot receive the pulse current signal on the non-target optical cable, so that the identification of the whole optical cable is completed.
2. The method for identifying the joint in the middle of the optical cable section comprises the steps of directly-buried laying optical cables and pipeline laying optical cables. Referring to fig. 5, all the optical cable metal reinforced cores and the metal sheaths at the end a are disconnected from the ground, one end of the signal generator is grounded, the other end of the signal generator is connected to the metal reinforced core or the metal sheath at the end a of the target optical cable, and the end B of the optical cable may not be processed. The loop resistance is tested by using the loop resistance detection function of the signal generator, the loop resistance is generally infinite, and the condition that the metal component of the optical cable is not continuous, an optical cable joint is arranged in the middle or the opposite end is not grounded is shown. At the moment, the pulse current forms a loop by depending on the distributed capacitance of the optical cable metal component to the ground, and from the manhole 1 to the manhole N-1, the signal receiver receives the pulse current signal on the target optical cable, and cannot receive the pulse current signal on the non-target optical cable; from the manhole N at the joint to the end B, the signal receiver cannot receive the pulse signal. There are three methods for identifying the optical cable behind the positioning joint, the first method is to connect the signal generator to the B end of the optical cable, the signal receiver starts from the manhole M + N and reaches to the manhole N +1, the signal receiver will receive the pulse current signal in the loop, the receiver will have no signal from the manhole N to the a end, for the identification of the optical cable in the manhole N, it should depend on other means, such as: A. the matching and butt joint of the outgoing cable holes at the B end, the matching and butt joint of the optical cable models, manual investigation on one side of the optical cable section and the like are completed; the second method is to wind a certain length of metal film adhesive tape on the outer sheath of the optical cable at the end of the joint box 2 to form a capacitor, and couple the test signal to the optical cable at the other end of the joint box by the capacitor, thereby achieving the whole-process test of the whole optical cable section; the third method is to open the splice closure to connect the cable metal components inside, thereby achieving a full-range test of the entire cable segment. Particularly, under the condition that a joint is arranged in the middle of an optical cable section, if the loop resistance measured by the loop resistance detection function of the signal generator carried by the A end is less than 30K omega, the situation that the metal component of the optical cable has the fault of unqualified insulation and the problem of water inlet of the optical cable joint box possibly exists is shown, at the moment, the loop current mainly depends on the ground resistance of the optical cable metal component in the joint box to form a loop to the ground, and a signal receiver receives a pulse current signal in the optical cable loop to be detected from the manhole 1 to the optical cable entering from the direction of the joint box A in the manhole N; and conversely, the signal generator is connected to the section B of the optical cable, and the signal receiver is also the same. The other optical cables which are not to be checked do not have pulse current signals, and the signal receiver does not receive the pulse current signals, so that the identification of the whole section of the optical cable to be checked is completed;
3. an identification method for aerial laying optical cable and optical cable section with joint in the middle. Referring to fig. 6, all the optical cables at the end a are disconnected from the ground, the end a of the optical cable to be identified is connected to the signal generator, and the end B may not be processed at first. The loop resistance is tested by using the loop resistance detection function of the signal generator, and at the moment, the loop resistance is infinite, which indicates that the metal component of the optical cable is not communicated with the ground, the optical cable connector is arranged in the middle or the opposite end is not grounded, and if the connector is not arranged in the middle, the opposite end must be grounded so as to form a pulse current loop; if the joint is arranged in the middle, the joint can be temporarily processed by adopting two methods, the first method is to wind a certain length of metal film adhesive tape on the outer protective sleeve of the optical cable at two ends of the joint box to form a capacitor, and a test signal is coupled to the optical cable at the other end of the joint box by the capacitor or the metal film is directly grounded at the joint box so as to form a current loop, thereby achieving the whole-process test of the whole optical cable section; the second method is to open the splice closure to connect the cable metal components inside to form a current loop, thereby achieving full-length testing of the entire cable segment. At this time, the signal receiver will receive the pulse current signal on the target optical cable, and will not receive the pulse current signal on the non-target optical cable.
4. An identification method for the man-hole with joint in the middle of the optical cable section by laying the optical cable in overhead and pipeline mixed mode. Referring to fig. 7, in this installation condition, the identification method is identical to the identification method of "directly-buried cable, pipeline cable, cable segment with joint in the middle", and the identification of the pole portion is identical to that of the cable in the pipeline, because the current fed from the a end forms a loop to the ground by means of the cable metal components installed in the man-well M +1 to the man-well M + 2.
5. An identification method for aerial and pipeline mixed laying optical cable and aerial joint in the middle of the optical cable section. Referring to fig. 8, under the laying condition, the signal generator is connected to the end a, the optical cable from the manhole 1 to the manhole M can be set, and similarly, the signal generator is connected to the end B, the optical cable from the manhole M +1 to the manhole N can be set, the optical cable on the rod road from the guide of the rod road is a recognition blind area, and the method is consistent with the recognition method of aerial laying optical cables and optical cable sections with joints in the middle.
Claims (10)
1. A method of identifying a target cable from a plurality of cables, comprising the steps of:
A. connecting one end of the output end of the signal transmitter to the ground, connecting the other end of the output end of the signal transmitter to a metal reinforced core or a metal sheath at the near end of the target optical cable, and testing the grounding resistance by using a loop resistance testing module arranged on the signal transmitter;
B. if the tested grounding resistance is infinite, a virtual grounding current loop is formed between the metal reinforcing core or the metal sheath in the optical cable and the ground in a capacitance mode, and a specific pulse signal is sent to the optical cable for detecting the specific pulse signal at the far end of the optical cable;
C. using a signal receiver to perform pulse signal identification on the optical cable in the remote identification area;
D. and identifying the optical cable with the specific waveform pulse signal as the target optical cable.
2. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: in the step B, when the tested grounding resistance is lower than the set threshold value, the optical cable is judged to be continuous and the opposite end is grounded, at the moment, the strength of the specific pulse signal is only required to be reduced, and the detection of the target optical cable can be completed through the steps C and D.
3. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: the pulse signal is a rectangular wave signal, and after the rectangular wave signal is fed into the target optical cable, the signal receiver at the far end detects, processes and identifies the pulse current signal in the optical cable at the far end.
4. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: the signal receiver receives pulse signals through the current sensor, the current sensor is an open type current transformer or a Rogowski coil, all optical cables are divided into a plurality of optical cables during detection, the current sensor is sleeved into the plurality of optical cables at each time, and whether a target optical cable is located in the optical cables is identified, so that the identification efficiency is improved.
5. The method for identifying a target optical cable from a plurality of optical cables as claimed in claim 1, wherein the step B of forming a virtual ground current loop between the metal reinforcing core or the metal sheath of the optical cable and the ground in a capacitive manner comprises two ways:
firstly, a virtual grounding current loop can be formed by distributed capacitance between a metal reinforced core or a metal sheath on a directly-buried or pipeline-laid optical cable and the ground;
second, a length of metal film tape is wrapped around the outer jacket of the distal end of the optical cable and grounded to form a virtual ground current loop.
6. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: if a joint is arranged in the middle of the optical cable section, the optical cable from the near end to the front end of the joint can be identified by utilizing a mode that a virtual ground current loop is formed between a metal reinforced core or a metal sheath in the optical cable and the ground in a capacitance mode, and if the optical cable on the other side of the joint needs to be identified, a signal transmitter only needs to be connected to the other end of the target optical cable.
7. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: if the middle of the optical cable section is provided with a joint, the optical cables at the two ends of the joint box are wound with the metal film adhesive tape to form a capacitor, and the pulse signals are coupled to the metal reinforced core or the metal sheath of the optical cable at the rear end by the capacitor, so that the whole-process identification of the whole optical cable can be realized.
8. The method of claim 1, wherein the identifying the target cable from the plurality of cables comprises: pulse current received by the current sensor is filtered, amplified and AD converted, and then DFT narrow-band filtering calculation is carried out in a digital signal mode, so that the signal-to-noise ratio of signals is improved.
9. Target cable identification device for implementing the method according to any one of claims 1 to 8, characterized in that it comprises at least:
the signal transmitter (1) is used for detecting the grounding resistance after being connected with a metal reinforced core or a metal sheath at the near end of a target optical cable and transmitting a pulse signal;
the signal receiver (2) is used for detecting a pulse signal on a target optical cable;
the signal transmitter (1) comprises a pulse signal generating module (11), a pulse power control module (12), an output conversion module (13), an output isolation transformer (14) and a loop resistance testing module (15), wherein the pulse signal generating module (11) is connected with the output conversion module (13) through the pulse power control module (12) and the output isolation transformer (14) in sequence; the output conversion module (13) is also connected with a loop resistance test module (15).
10. The target cable identification device of claim 9, wherein: the signal receiver (2) comprises a current sensor (21), a pre-amplification module (22), a signal processing module (23) and a signal display module (24), wherein the current sensor (21) is connected with the signal display module (24) sequentially through the pre-amplification module (22) and the signal processing module (23).
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