CN100410673C - Cable failure prefixed point detection method and detection device - Google Patents
Cable failure prefixed point detection method and detection device Download PDFInfo
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Abstract
The present invention relates to a cable fault prefixed point detecting method and a detecting device thereof, which belongs to the field of electrical fault detection. The present invention is characterized in that the output ends of a high voltage direct current pulse generating unit and an audio signal injecting unit are connected to one end of an electrifying unit, and the other end of the electrifying unit is connected with one end of a fault cable. The high voltage direct current pulse generating unit electrifies the fault cable through the electrifying unit, and the audio signal injecting unit superimposes an audio pulse direct current electric current to the cable in a period that electric arcs exist stably on the basis that the electric arcs are fired. Through an audio magnetic field receiving device which moves along a cable laid path, a magnetic field which is radiated by the audio pulse direct current electric current through the cable is received, according to the characteristic that a very large difference of the amplitude of the audio magnetic field in front of and behind a fault point exists, a user can judge that the audio magnetic field receiving apparatus is in the front or behind the point, and accordingly, the preliminary and coarse prefixed point detection to a cable fault point is rapidly carried out. The present invention can be widely used in the field of fault detection of various cables.
Description
Technical Field
The invention belongs to the field of detection of electrical faults, and particularly relates to detection and positioning of a high-resistance fault point of a power cable.
Background
With the development of social economy and the acceleration of modernized construction pace, the electricity consumption of industrial and agricultural production and people's life is increasing day by day, the demand for electric power is increasing, and the requirement for safe operation of a power grid is also increasing.
As power cables for connecting various electric devices, transmitting and distributing electric power, the positions of overhead wires have been gradually replaced. The transmission performance of cable power supply is more stable than that of an overhead line in cities and countryside, the reliability is high, the occupied area is small, the influence on the city appearance cannot be caused, and the restriction of natural environment is avoided, so that the safety of power supply is improved. The power transmission and distribution mode of largely adopting underground power cable lines to replace overhead power transmission lines has become a main trend of future development of domestic and foreign power transmission and distribution networks.
Power cables play a critical role in power systems as a carrier for transmitting and distributing electrical energy and for connecting various electrical devices, etc., and therefore, maintaining safe operation of the cables is a vital task.
Theoretically, the power cable is less influenced by external environmental factors and human factors, and the reliability of safe operation is high. However, long-term accumulated power cable operation experience and experimental research results prove that the power cable line is easy to have cable operation faults within the period of 1-5 years after the power cable line is put into operation.
The main reasons of the operation failure of the power cable are external force damage, the manufacturing quality defect of the cable accessory, the installation quality defect of the cable or the manufacturing quality defect of the cable body and the like.
The cable has a complex fault condition, and in order to shorten the time for searching and repairing the fault and not influence the normal power supply, a quick and effective measuring and searching method is required to be adopted to quickly and accurately find out the fault point and carry out emergency repair.
The power cable fault test is generally divided into two steps: firstly, "rough measurement" and secondly "fixed point". Firstly, selecting a correct test method according to a fault phenomenon, and measuring an approximate range of a fault point, namely 'rough measurement'; the device is then used to determine the specific location of the failure point, i.e., the "fix point".
The Chinese patent application with publication number CN1101984A, published as 26.4.1995, discloses a high-voltage discharge method for detecting the disconnection point of a cable, which is characterized in that the output end of a high-voltage small current generator is connected to one side of a disconnection pair, and the other side of the disconnection pair is short-circuited. The high voltage generates discharge at the disconnection point, and the discharge generates sound. The probe 3 is moved along the sheath of the cable by a radio with a probe, and when the radio is moved to a place with a discharging sound, the position is a broken line point.
However, the method can only be applied to short-distance and short-distance cabling small-range detection and fault finding (namely the fixed-point detection), has low detection speed, is easily interfered by surrounding electromagnetic fields, has higher requirements on detection environment and users, and is not applicable to long-distance cabling, cables laid in a direct-buried mode or occasions with large electromagnetic interference of the surrounding environment.
Chinese patent No. CN1013618B, entitled "system and apparatus for detecting ground fault of electric power equipment", published as 1992, month 4 and 8, discloses a system and apparatus for detecting ground fault of electric power equipment, in which two magneto-optical sensors are separately installed at both ends of a section of a cable, a signal from the magneto-optical sensors is transmitted to a photo-electric conversion circuit connected thereto through an optical fiber cable connected thereto, a discrimination circuit determines whether or not a ground fault has occurred and where the fault is located based on an output signal of the photo-electric conversion circuit, and the determination is made based on a difference in magnetic value or phase or a combination of both between output signals of the photo-electric conversion circuit. Although the detection problem of long-distance laid cables is solved, the whole detection device relates to a magneto-optical sensor and an optical fiber cable with the same length as the detected cable, the implementation cost is high, the optical fiber cable needs to be laid synchronously when the cable is laid, the detection device is not suitable for fault point detection of the laid cable, and a user has certain difficulty in implementation.
Disclosure of Invention
The invention aims to solve the technical problem of providing a cable fault presetting point detection method and a detection device which can carry out quick preliminary detection on cable fault points of cables which are directly laid, directly buried or laid by penetrating through non-metal pipes in a long distance range, are simple and practical and have low manufacturing cost.
The technical scheme of the invention is as follows: the cable fault presetting point detection method is characterized by comprising the following steps:
(1) connecting the output ends of the high-voltage direct current pulse generation unit and the audio signal injection unit to one end of a discharge unit, and connecting the other end of the discharge unit to one end of a fault cable;
(2) the high-voltage direct-current pulse generation unit discharges the fault cable through the discharge unit, and an electric arc is ignited and maintained at the fault point of the fault cable;
(3) in a time period when the electric arc stably exists, an audio frequency pulsating direct current is superposed on the cable on the basis of the ignited electric arc by an audio frequency signal injection unit;
(4) receiving the magnetic field radiated by the audio pulsating direct current through the cable by an audio magnetic field receiving device moving along the cable laying path;
(5) according to the characteristic that the amplitude of the audio magnetic field is greatly different before and after the fault point, the audio magnetic field receiving device is judged to be positioned in front of or behind the fault point, and therefore preliminary rough detection preset point detection is rapidly carried out on the cable fault point.
The output end of the high-voltage direct current pulse generation unit is also connected with an arc continuation unit, the arc continuation unit supplements energy to the ignited electric arc to prolong the existence duration of the electric arc, and the high-voltage direct current pulse generation unit and the arc continuation unit are connected in parallel or in series with the audio signal injection unit.
The running time of the audio signal injection unit is shorter than the time of the high-voltage direct current pulse generation unit and the arc continuation unit for causing electric arcs at the fault points of the cables.
The audio frequency pulsating direct current is intermittent audio frequency pulsating direct current.
The invention also provides a cable fault presetting point detection device adopting the detection method, which comprises a signal generating part and a signal receiving part, wherein the output end of the signal generating part is connected with one end of a fault cable, and the signal receiving part can move along the laying path of the cable, and is characterized in that: the signal generating part comprises a high-voltage direct-current pulse generating unit, a continuous arc unit, an audio signal injection unit and a discharging unit, wherein the output ends of the high-voltage direct-current pulse generating unit, the continuous arc unit and the audio signal injection unit are connected in parallel or in series and then connected to one end of the discharging unit, and the other end of the discharging unit is connected with one end of a fault cable; the high-voltage direct-current pulse generating unit discharges to a fault cable and ignites an electric arc at a fault point of the fault cable; the arc continuation unit supplements energy to the ignited arc, and prolongs the arc duration; the audio signal injection unit superposes an audio pulsating direct current on the cable in a time period when the electric arc stably exists; the signal receiving part is a magnetic field detection, amplification and display device.
The high-voltage direct current pulse generating unit comprises a direct current high-voltage generator 9, a high-voltage capacitor C1 and a current-limiting resistor R1; the output end of the direct current high-voltage generator 9 is connected with one end of a high-voltage capacitor C1 and a current-limiting resistor R1, the other end of the high-voltage capacitor C1 is grounded, and the other end of the current-limiting resistor R1 is connected with one end of a discharge unit; the direct current high voltage generator charges the high voltage capacitor, and the current limiting resistor plays a damping role in discharging current of the high voltage capacitor.
The continuous arc unit comprises a direct current power supply 10, a capacitor C2 and a one-way conduction device VD 1; the audio signal injection unit comprises a direct current power supply 11, a high-power electronic switch 12, a one-way conduction device VD5, an audio square wave generator 13 and a control circuit 14; the capacitor C2 is connected in parallel at two ends of the DC power supply 10, the output end of the DC power supply 10 is connected with one end of the one-way conduction device VD1, and the other end of the one-way conduction device VD1 is connected with one end of the discharge unit; the output end of the direct current power supply 11 is connected with the input end of the high-power electronic switch 12, the output end of the high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device VD5, and the control circuit 14 is connected with the control end of the high-power electronic switch device 12 through an audio square wave generator 13; the direct current power supply 10 charges a capacitor C2, and automatically supplements current to the ignited electric arc through a one-way conduction device VD1, so that the storage time of the electric arc is prolonged; the one-way conducting device VD1 plays a role in one-way isolation; under the control of a high-power electronic switch 12, a direct current power supply 11 and an audio square wave generator 13 superpose and inject an intermittent audio pulse direct current to a cable on the basis of an ignited arc; the one-way conducting device VD5 plays a role in one-way isolation; the high-power electronic switch is controlled to be switched on and off by an audio square wave generator and a control circuit.
Or, the continuous arc unit comprises a direct current power supply 10, a capacitor C2 and a one-way conducting device VD 1; the audio signal injection unit comprises a direct current power supply 11, a high-power electronic switch 12, unidirectional conducting devices VD3 and VD5, an audio square wave generator 13 and a control circuit 14; the direct current power supply 10 is connected in series with the direct current power supply 11, and the capacitor C2 and the one-way conduction device VD1 are connected in parallel at two ends of the direct current power supply 10; the output end of the direct current power supply 11 is connected with the input end of the high-power electronic switch 12, the output end of the high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device VD5, and the control circuit 14 is connected with the control end of the high-power electronic switch device 12 through an audio square wave generator 13; the one-way conducting device VD3 is connected in parallel between the serial connection point of the DC power supply 10 and the DC power supply 11 and the output end of the high-power electronic switch 12; the direct current power supply 10 charges a capacitor C2, and automatically supplements current to the ignited electric arc through one-way conduction devices VD1, VD3 and VD5, so that the storage time of the electric arc is prolonged; the one-way conducting device VD1 plays a role in one-way isolation; under the control of a high-power electronic switch 12, a direct current power supply 11 and an audio square wave generator 13 superpose and inject an intermittent audio pulse direct current to a cable on the basis of an ignited arc; the unidirectional conducting devices VD3 and VD5 play a role of unidirectional isolation, and the high-power electronic switch is controlled to be switched on and off by the audio square wave generator and the control circuit.
Or, the audio signal injection unit comprises at least two groups of direct current power supplies 11A and 11B, each group of direct current power supplies is correspondingly provided with a corresponding high-power electronic switch, a one-way conduction device, an audio square wave generator and a control circuit: the direct current power supplies 11A and 11B are connected in series with the direct current power supply 10 of the continuous arc unit, the output ends of the direct current power supplies 11A and 11B are respectively connected with the input ends of the corresponding high-power electronic switches, the output end of each high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device, and each control circuit is connected with the control end of the corresponding high-power electronic switch through an audio square wave generator.
Furthermore, a current limiting resistor R2 or R3 is arranged between the direct current power supply 10 and the unidirectional conducting device VD1 or between the high-power electronic switch and the unidirectional conducting device VD 5; wherein, resistance R2 is used for prolonging the time that the electric arc lasts: the resistor R3 is used to protect high power electronic switching devices.
Compared with the prior art, the invention has the advantages that:
1. the audio pulse signal superposition injection mode is used, so that the tested cable generates an audio current magnetic field which is easy to detect before a fault point, when a user drives a magnetic field signal receiver to move along the cable, whether the cable passes the fault point or not can be known clearly, and the fault point of various directly-laid, directly-buried or through-pipe laid cables can be rapidly and preliminarily determined;
2. the principle and the method are simple and practical, the approximate position of a fault point can be quickly judged within a large-area range, the fault finding time and the processing workload of long-distance cable laying can be greatly shortened, and the loss of power failure faults to users is reduced;
3. the device has relatively low manufacturing cost, is easy to be accepted by users and is convenient to popularize.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a flow chart of the detection steps and method of the present invention;
FIG. 2 is a schematic view of a connection of the detecting unit of the present invention;
FIG. 3 is a schematic view of another connection of the detecting unit of the present invention;
FIG. 4 is a schematic view of another embodiment of the present invention;
FIG. 5 is a schematic diagram of waveforms at various points in FIG. 2;
FIG. 6 is a circuit diagram of an embodiment of an audio square wave generator;
FIG. 7 is a circuit diagram of an embodiment of a control circuit;
FIG. 8 is a waveform diagram of various points of the control circuit;
FIG. 9 is a circuit diagram of an embodiment of a DC high voltage generator;
fig. 10 is a circuit diagram of an embodiment of a dc power supply.
In the figure, 1 is the detection device, 2 is an audio magnetic field signal receiver, 3 is a fault cable to be detected, 4 is a fault point, 5 is a high-voltage direct current pulse generation unit, 6 is a continuous arc unit, 7 is an audio signal injection unit, 8 is a discharge unit, 9 is a direct current high-voltage generator, 10, 11A and 11B are direct current power supplies, 12A and 12B are high-power electronic switches, 13 is an audio square wave generator, and 14 is a control circuit.
Detailed Description
In fig. 1, the present invention provides a method for detecting a predetermined point of cable fault, which comprises the following steps:
(1) connecting the output ends of a high-voltage direct-current pulse generation unit, a continuous arc unit and an audio signal injection unit in parallel at one end of a discharge unit, wherein the other end of the discharge unit is connected with a phase line at one end of a fault cable;
(2) the high-voltage direct-current pulse generation unit discharges the fault cable through the discharge unit, and an electric arc is ignited and maintained at the fault point of the fault cable;
(3) the arc continuation unit supplements energy to the ignited arc, and prolongs the arc duration;
(4) in a time period when the electric arc stably exists, an audio frequency pulsating direct current is superposed on the cable on the basis of the ignited electric arc by an audio frequency signal injection unit;
(5) receiving the magnetic field radiated by the audio pulsating direct current through the cable by an audio magnetic field receiving device moving along the cable laying path;
(6) according to the characteristic that the amplitude of the audio magnetic field before the fault point is greatly higher than the amplitude of the audio magnetic field after the fault point, the audio magnetic field receiving device is judged to be in front of or behind the fault point, and therefore preliminary rough detection preset point detection is rapidly carried out on the cable fault point.
The running time of the audio signal injection unit is shorter than the time of the high-voltage direct current pulse generation unit and the arc continuation unit for causing electric arcs at the fault points of the cables.
The audio frequency pulsating direct current is intermittent audio frequency pulsating direct current.
In fig. 2, the cable failure predetermined point detecting apparatus using the detecting method described in fig. 1 includes a signal generating section 1 whose output end is connected to one end of a failed cable 3 and a signal receiving section 2 which is movable along a cable laying path.
The signal generating part comprises a high-voltage direct-current pulse generating unit 5, a continuous arc unit 6, an audio signal injection unit 7 and a discharging unit 8, wherein the output ends of the high-voltage direct-current pulse generating unit, the continuous arc unit and the audio signal injection unit are connected in parallel or in series (in the figure, the output ends are in a parallel connection mode) and then connected to one end of the discharging unit, the other end of the discharging unit is connected with one end of a fault cable, and a fault point of the cable is represented by 4.
The high-voltage direct-current pulse generating unit discharges to a fault cable and ignites an electric arc at a fault point of the fault cable; the arc continuation unit supplements energy to the ignited arc, and prolongs the arc duration; the audio signal injection unit superposes an audio pulsating direct current on the cable in a time period when the electric arc stably exists; the signal receiving part is a magnetic field detection, amplification and display device.
Specifically, the high-voltage direct current pulse generating unit 5 comprises a direct current high-voltage generator 9, a high-voltage capacitor C1 and a current-limiting resistor R1; the output end of the direct current high voltage generator 9 is connected with one end of a high voltage capacitor C1 and a current limiting resistor R1, the other end of the high voltage capacitor C1 is grounded, and the other end of the current limiting resistor R1 is connected with one end of the discharge unit.
The direct current high voltage generator charges the high voltage capacitor, and the current limiting resistor plays a damping role in discharging current of the high voltage capacitor.
The arc continuing unit 6 comprises a direct current power supply 10 (for the convenience of understanding, a battery symbol is used for representing the battery symbol in the figure, and the same is used below), a capacitor C2 and a one-way conduction device VD 1; the audio signal injection unit 7 comprises a direct current power supply 11, a high-power electronic switch 12, a one-way conduction device VD5, an audio square wave generator 13 and a control circuit 14; the capacitor C2 is connected in parallel at two ends of the DC power supply 10, the output end of the DC power supply 10 is connected with one end of the one-way conduction device VD1, and the other end of the one-way conduction device VD1 is connected with one end of the discharge unit; the output end of the direct current power supply 11 is connected with the input end of the high-power electronic switch 12, the output end of the high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device VD5, and the control circuit 14 is connected with the control end of the high-power electronic switch 12 through the audio square wave generator 13.
The direct current power supply 10 charges a capacitor C2, and automatically supplements current to the ignited electric arc through a one-way conduction device VD1, so that the storage time of the electric arc is prolonged; the one-way conducting device VD1 plays a role in one-way isolation; under the control of a high-power electronic switch 12, a direct-current power supply 11 and an audio square-wave generator 13 superpose and inject a large-amplitude intermittent audio-frequency pulsating direct current to a cable on the basis of an ignited arc; the one-way conducting device VD5 plays a role in one-way isolation; the high-power electronic switch is controlled to be switched on and off by an audio square wave generator and a control circuit.
The dc high voltage generator 9 may be composed of a power frequency high voltage transformer and a high voltage silicon stack, or may be a switching power supply type intermediate frequency or high frequency dc high voltage generator.
The direct current high voltage generator charges the high voltage capacitor, and the current limiting resistor plays a damping role in discharging current of the high voltage capacitor. The protection between units and the discharge of a fault cable are realized by the one-way conductive characteristic of the one-way conductive element-silicon stack in the units.
The output voltage of the high voltage DC generator is preferably above 3000V. The dc high voltage generator in this figure is a negative polarity output.
The resistance value of the current limiting resistor R1 can be selected between 10 omega and 1000 omega according to different output voltages of the high-voltage direct current pulse generation unit.
The capacitance of the capacitor C2 in the arc-continuing unit is preferably larger than that of C1, and the capacitance of C2 is large, which is beneficial to prolonging the arc-continuing time.
The high-power electronic switch can be an IGBT, a high-power triode, an MOS tube or other high-power electronic switch devices, and the types of the high-power electronic switch devices are selected as follows:
IGBT: BSM75GB120DN2, BSM100GB120DN2, SKM 100 GAR 123D, FF100R12KS4, or FMG2G75US 120;
a high-power MOS tube: STE50DE100, IXFB80N50Q, IXFB38N100Q, IRFIB5N50L, or IRFPS40N 60K;
the silicon controlled rectifier can be turned off: 5SGA 06D 4502.
The high-power electronic switch is controlled to be switched on and off by the audio square wave generator and the control circuit.
The unidirectional devices VD 1-VD 5 can be silicon stacks, diodes or controllable silicon.
A time control circuit in the control circuit controls the audio square wave generator to start to operate within a plurality of milliseconds after the discharge device (if the discharge device is controllable) is closed, or a time control circuit is started after a current pulse detection device detects the pulse current output of the high-voltage direct current pulse generation unit, so that the audio square wave generator is controlled to start to operate within a plurality of milliseconds after an electric arc is ignited.
After the audio square wave generator starts to operate for a plurality of milliseconds, the time control circuit controls the audio square wave generator to stop working, and the high-power electronic switch is in a turn-off state before and after the audio square wave generator stops working.
The running time of the audio square wave generator is shorter than the time of the high-voltage direct current pulse generating unit and the arc continuing unit for causing electric arcs at the fault points of the cable.
A current limiting resistor R2 or R3 is arranged between the direct current power supply 10 and the unidirectional conducting device VD1 or between the high-power electronic switch and the unidirectional conducting device VD 5; wherein, the resistor R2 is used for prolonging the arc duration; the resistor R3 is used to protect high power electronic switching devices. According to the test result, the two resistors are selected to be ohmic resistors.
The discharge unit 8 is a high voltage relay, a contact point driven by an electromagnet or a discharge ball with adjustable discharge gap, which belongs to the prior art and is not described in detail herein.
The signal receiving part is a magnetic field detection, amplification and display device, which belongs to the prior art and is not described in detail herein.
In this figure, there is substantially a current superposition relationship between the arc continuation unit and the audio signal.
Through the devices and the connection relation, intermittent large-amplitude audio-frequency pulsating direct current is injected into the cable to be detected, the audio-frequency current is short-circuited by electric arcs at a cable fault point 4 and does not continuously propagate forwards, a magnetic field radiated by the current through the cable is received through the magnetic field detection, amplification and display device, the amplitude of the audio-frequency magnetic field before the fault point is greatly higher than that of the audio-frequency magnetic field after the fault point, and the position of the magnetic field detection device and the front or the back of the fault point can be judged through the method.
In fig. 3, the continuous arc unit and the audio signal injection unit are connected in series.
The arc continuing unit comprises a direct-current power supply 10, a capacitor C2 and a one-way conducting device VD 1; the audio signal injection unit comprises a direct current power supply 11, a high-power electronic switch 12, unidirectional conducting devices VD3 and VD5, an audio square wave generator 13 and a control circuit 14.
The DC power supply 10 and the DC power supply 11 are connected in series, and the capacitor C2 and the one-way conduction device VD1 are connected in parallel at two ends of the DC power supply 10.
The output end of the direct current power supply 11 is connected with the input end of the high-power electronic switch 12, the output end of the high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device VD5, and the control circuit 14 is connected with the control end of the high-power electronic switch 12 through the audio square wave generator 13.
The one-way conducting device VD3 is connected in parallel between the serial connection point of the DC power supply 10 and the DC power supply 11 and the output end of the high-power electronic switch 12.
The direct current power supply 10 charges a capacitor C2, and automatically supplements current to the ignited electric arc through one-way conduction devices VD1, VD3 and VD5, so that the storage time of the electric arc is prolonged; the unidirectional device VD1 plays the role of unidirectional isolation.
Under the control of a high-power electronic switch 12, a direct current power supply 11 and an audio square wave generator 13 superpose and inject an intermittent audio pulse direct current to a cable on the basis of an ignited arc; the one-way conducting devices VD3 and VD5 play a role in one-way isolation; the high-power electronic switch is controlled to be switched on and off by an audio square wave generator and a control circuit.
The rest is the same as fig. 2.
In this figure, the continuous arc unit and the audio signal are substantially in a current/voltage superposition relationship.
The purpose of adopting the series connection of the direct current power supplies 10 and 11 is to reduce the voltage and the capacity of the direct current power supply 11, reduce the volume of the whole device and the requirement on the direct current power supply, and be more beneficial to engineering and improve the practicability.
In fig. 4, the audio signal injection unit adopts a two-stage series circuit structure, and the continuous arc unit and the audio signal injection unit are connected in series.
The audio signal injection unit comprises at least two groups of direct current power supplies 11A and 11B, and each group of direct current power supplies is correspondingly provided with a corresponding high-power electronic switch, a one-way conduction device, an audio square wave generator and a control circuit (for simplification, the audio square wave generator and the control circuit are not shown in the figure).
The direct current power supplies 11A and 11B are connected in series with the direct current power supply 10 of the continuous arc unit, the output ends of the direct current power supplies 11A and 11B are respectively connected with the input ends of the corresponding high-power electronic switches, the output end of each high-power electronic switch is connected with one end of the discharge unit through a one-way conduction device, and each control circuit is connected with the control end of the corresponding high-power electronic switch through an audio square wave generator.
The rest is the same as fig. 2 or fig. 3.
At least two groups of direct current power supplies 11A and 11B are arranged, each group of direct current power supplies is correspondingly provided with a corresponding high-power electronic switch, a one-way conduction device, an audio square wave generator and a control circuit, and the purpose is to reduce the voltage withstanding requirement on the high-power electronic switch and reduce the voltage grade of the direct current power supplies 11A and 11B so as to reduce the volume and the manufacturing cost of the whole device.
According to this concept, the arc continuing unit may also adopt a circuit structure form in which two or more dc power supplies are connected in series, so as to further reduce the requirements on the voltage and capacity of each dc power supply, and the specific circuit thereof can be easily implemented by those skilled in the art, and will not be described herein.
In fig. 5, the circuit configuration of fig. 2 is taken as an example to illustrate the operation waveforms of various points of the present device, so as to help understand the operation principle of the present invention.
The high-voltage direct-current pulse generator comprises a high-voltage direct-current pulse generating unit, an arc continuation unit, an audio signal injection unit, a cable, a signal receiver and a signal receiver, wherein A is an output voltage waveform diagram when the high-voltage direct-current pulse generating unit works alone, B is an output voltage waveform diagram when the arc continuation unit works alone, C is an output voltage waveform diagram when the audio signal injection unit works alone, D is a signal voltage waveform diagram injected into the cable most when the units work together, E is a signal received by the signal receiver before a cable fault point and is subjected to resonance, filtering and amplification, and F is a signal received by the signal receiver after the cable fault point and is subjected.
It can be seen that the discharge time of A is extremely short, the discharge time of B is greatly prolonged, C outputs audio pulsating direct current, the three are superposed to achieve the effect of D, and the comparison of E and F shows that the signal received by the magnetic field detection device before the fault point is far stronger than the signal after the fault point.
Fig. 6 shows an implementation of the audio square-wave generator 13, which is an oscillator circuit composed of a time-base integrated circuit 555 (IC number is U401 in the figure) and its peripheral circuits, and its 3 pins output audio square-wave signals, which are controlled by PORT1 control PORT through and gate to allow or prohibit output, and finally the signals are output by PORT2 PORT, PORT1 is high (logic 1) to allow output, and low (logic 0 to prohibit output), and the level of PORT2 is low when output is prohibited.
U402 in the figure is a conventional AND gate circuit, and other elements have no special requirements.
The audio square wave generator can adopt a conventional square wave generating circuit, and can also adopt a conventional sine wave generating circuit to obtain a required square wave signal after conversion/shaping, which belongs to the prior art and is not described again.
Fig. 7 shows an implementation of the control circuit 10, in which the control circuit is an oscillator circuit formed by the U501 time-base integrated circuit 555, and is used to control the on/off of the discharging device 8, output a high level (logic 1) to control the contact of the discharging device 8 to be closed, and output a low level (logic 0) to control the contact of the discharging device 8 to be opened. The time for outputting logic 1 is between 0.1 second and 1 second, and the time for outputting logic 0 is between 1 second and 10 seconds (see the waveform at the point H in fig. 8).
In addition, the differentiating circuit is composed of C503 and R504, VD501 controls to allow only positive polarity pulse to pass through, and converts the signal rising edge of the H point into positive polarity spike, VT501 and R503 compose an inverter circuit, and changes the positive polarity spike into negative polarity spike (see the I point waveform in figure 8). This sharp pulse triggers a monostable one consisting of a U502 time base integrated circuit 555, which outputs a positive polarity pulse of fixed width (see waveform at point J in fig. 8). This signal is changed into a negative polarity pulse by an inverter constituted by R506, VT502, R507 (see the waveform at the point K in fig. 8). The pulse passes through a differentiating circuit consisting of C506, R508 and VD502 and a one-way conduction circuit to convert the rising edge of the pulse into a negative spike (see the L-point waveform in figure 8). This sharp pulse triggers a monostable circuit two consisting of a U503 time base integrated circuit 555, which outputs a positive polarity pulse of fixed width (see the waveform at point M in fig. 8).
The first monostable circuit is used for generating a trigger signal of a second monostable circuit, the trigger signal is a plurality of milliseconds after the contact of the discharging device is closed, the second monostable circuit is used for generating a control signal of the audio square wave generator, the audio square wave generator is controlled by the control signal to stop outputting after the audio square wave generator outputs for a plurality of milliseconds, and the output stopping time is always before the contact of the discharging device is separated.
Fig. 8 is a waveform diagram of various points of the control circuit, the specific meaning of which has been described in the description of fig. 7.
Fig. 9 is an implementation of the dc high voltage generator 9, in which a T101 high voltage power frequency transformer boosts the input 220V ac mains, a V101 silicon stack controls the unidirectional conduction, and R101 performs current limiting protection.
Fig. 5 is an implementation of a dc power supply, in which a T201 power frequency transformer transforms and isolates an input 220V ac mains, a B201 rectifier bridge rectifies the input mains, and R201 performs current limiting protection.
The method and the device are adopted to carry out field test, and the test result is as follows:
| serial number | Condition of cable | Actual position of fault point from cable starting point | Range of predetermined points | Pre-fault signal strength | |
|
| 1 | Cable voltage class: 10 KV. And (3) overall length: 1200 meter failure property: core wire to armor breakdown fault resistance: 5M | 1050 m | Front and back 2 | 60dB | 30dB | |
| 2 | Voltage class: 10 KV. And (3) overall length: 560 m failure property: core wire to armor breakdown fault resistance: 1M | 360 m | Front and back 3 | 65dB | 35dB | |
| 3 | Voltage class: 600V. And (3) overall length: 210 m failure property: core-to-ground breakdown fault resistance: 20K | 90 m | Front and back 1.5 m | 80dB | 20dB |
The data show that the invention can rapidly and preliminarily measure the cable fault point of the cable which is directly laid, directly buried or through-pipe laid in a long distance range, has obvious signal intensity contrast and is easy to master and implement by users.
The invention adopts the mode of injecting-superposing audio pulse direct current signals on the cable to be detected and detecting the current magnetic field thereof to detect, when a user drives the magnetic field signal receiver to move along the cable, the user can clearly know whether the user has passed the fault point, and the approximate position of the fault point can be rapidly judged in a large area range for various directly-laid, directly-buried or through-pipe laid cables, so that the fault finding time and the processing workload of the long-distance laid cable can be greatly shortened, the loss of power failure faults to the user can be reduced, the manufacturing cost of the device is relatively low, the device is easy to accept and implement by the user, and the popularization is convenient.
The invention can be widely applied to the field of fault detection of various cables which are directly buried, laid through non-metal pipes or laid in cable tunnels.
Claims (10)
1. A cable fault presetting point detection method is characterized in that:
(1) connecting the output ends of the high-voltage direct current pulse generation unit and the audio signal injection unit to the first end of the discharge unit, and connecting the second end of the discharge unit to one end of the fault cable;
(2) the high-voltage direct-current pulse generation unit discharges the fault cable through the discharge unit, and an electric arc is ignited and maintained at the fault point of the fault cable;
(3) in a time period when the electric arc stably exists, an audio frequency pulsating direct current is superposed on the cable on the basis of the ignited electric arc by an audio frequency signal injection unit;
(4) receiving the magnetic field radiated by the audio pulsating direct current through the cable by an audio magnetic field receiving device moving along the cable laying path;
(5) according to the characteristic that the amplitude of the audio magnetic field is greatly different before and after the fault point, the audio magnetic field receiving device is judged to be positioned in front of or behind the fault point, and therefore preliminary rough detection preset point detection is rapidly carried out on the cable fault point.
2. The method for detecting the cable fault preset point according to claim 1, wherein an arc continuing unit is connected to an output end of the high-voltage direct current pulse generating unit, the ignited electric arc is supplemented with energy by the arc continuing unit, the existence time of the electric arc is prolonged, and the high-voltage direct current pulse generating unit and the arc continuing unit are connected with the audio signal injection unit in parallel or in series.
3. The cable fault predetermined point detecting method as claimed in claim 2, wherein the operating time of the audio signal injecting unit is shorter than the time when the high voltage direct current pulse generating unit and the arc continuing unit induce an arc at the cable fault point.
4. The method of cable fault pre-determined point detection as claimed in claim 1, wherein said audio pulsating direct current is an intermittent audio pulsating direct current.
5. A cable failure predetermined point detecting apparatus using the detecting method according to claim 1, comprising a signal generating section whose output terminal is connected to an end of a failed cable and a signal receiving section which is movable along a running path of the cable, characterized in that:
the signal generating part comprises a high-voltage direct-current pulse generating unit, a continuous arc unit, an audio signal injection unit and a discharging unit, wherein the output ends of the high-voltage direct-current pulse generating unit, the continuous arc unit and the audio signal injection unit are connected in parallel or in series and then connected to the first end of the discharging unit, and the second end of the discharging unit is connected with one end of a fault cable;
the high-voltage direct-current pulse generating unit discharges to a fault cable and ignites an electric arc at a fault point of the fault cable;
the arc continuation unit supplements energy to the ignited arc, and prolongs the arc duration;
the audio signal injection unit superposes an audio pulsating direct current on the cable in a time period when the electric arc stably exists;
the signal receiving part is a magnetic field detection, amplification and display device.
6. The cable fault pre-determined point detection device of claim 5, wherein the high voltage direct current pulse generation unit comprises a direct current high voltage generator (9), a high voltage capacitor C1 and a current limiting resistor R1:
the output end of the direct-current high-voltage generator (9) is connected with one end of a high-voltage capacitor C1 and one end of a current-limiting resistor R1, the other end of the high-voltage capacitor C1 is grounded, and the other end of the current-limiting resistor R1 is connected with the first end of the discharge unit;
the direct current high voltage generator charges the high voltage capacitor, and the current limiting resistor plays a damping role in discharging current of the high voltage capacitor.
7. The cable fault pre-determined point detection device as recited in claim 5, wherein said arc continuing unit comprises a first dc power source (10), a capacitor C2 and a one-way conducting device VD 1; the audio signal injection unit comprises a second direct-current power supply (11), a high-power electronic switch (12), a one-way conduction device VD5, an audio square wave generator (13) and a control circuit (14);
the capacitor C2 is connected in parallel at two ends of the first direct current power supply (10), the output end of the first direct current power supply (10) is connected with one end of the one-way conduction device VD1, and the other end of the one-way conduction device VD1 is connected with the first end of the discharge unit;
the output end of the second direct current power supply (11) is connected with the input end of the high-power electronic switch (12), the output end of the high-power electronic switch is connected with the first end of the discharge unit through a one-way conduction device VD5, and the control circuit (14) is connected with the control end of the high-power electronic switch device (12) through an audio square wave generator (13);
a first direct current power supply (10) charges a capacitor C2, and automatically supplements current to the ignited electric arc through a one-way conduction device VD1, so that the storage time of the electric arc is prolonged; the one-way conducting device VD1 plays a role in one-way isolation;
a second direct current power supply (11) and an audio square wave generator (13) are controlled by a high-power electronic switch (12), and an intermittent audio pulsating direct current is injected into the cable in a superposition mode on the basis of an ignited arc; the one-way conducting device VD5 plays a role in one-way isolation; the high-power electronic switch is controlled to be switched on and off by an audio square wave generator and a control circuit.
8. The cable fault pre-determined point detection device as recited in claim 5, wherein said arc continuing unit comprises a first dc power source (10), a capacitor C2 and a one-way conducting device VD 1; the audio signal injection unit comprises a second direct-current power supply (11), a high-power electronic switch (12), unidirectional conducting devices VD3 and VD5, an audio square-wave generator (13) and a control circuit (14);
the first direct-current power supply (10) is connected with the second direct-current power supply (11) in series, and the capacitor C2 and the one-way conduction device VD1 are connected to two ends of the first direct-current power supply (10) in parallel; the output end of the second direct current power supply (11) is connected with the input end of the high-power electronic switch (12), the output end of the high-power electronic switch is connected with the first end of the discharge unit through a one-way conduction device VD5, and the control circuit (14) is connected with the control end of the high-power electronic switch device (12) through an audio square wave generator (13);
the one-way conduction device VD3 is connected in parallel between the serial connection point of the first direct current power supply (10) and the second direct current power supply (11) and the output end of the high-power electronic switch (12);
a first direct current power supply (10) charges a capacitor C2, and automatically supplements current to the ignited electric arc through unidirectional conducting devices VD1, VD3 and VD5 so as to prolong the storage time of the electric arc; the one-way conducting device VD1 plays a role in one-way isolation;
a second direct current power supply (11) and an audio square wave generator (13) are controlled by a high-power electronic switch (12), and an intermittent audio pulsating direct current is injected into the cable in a superposition mode on the basis of an ignited arc; the one-way conducting devices VD3 and VD5 play a role in one-way isolation; the high-power electronic switch is controlled to be switched on and off by an audio square wave generator and a control circuit.
9. The cable fault presetting point detecting device of claim 7 or 8, wherein the second direct current power supply comprises at least two groups of second direct current power supplies A, B, each group of direct current power supplies is correspondingly provided with a corresponding high-power electronic switch, a one-way conducting device, an audio square wave generator and a control circuit;
the second direct current power supply A, B is connected in series with the first direct current power supply (10) of the arc continuation unit, the output ends of the two groups of second direct current power supplies A, B are respectively connected with the input ends of the corresponding high-power electronic switches, the output end of each high-power electronic switch is connected with the first end of the discharge unit through a one-way conduction device, and each control circuit is connected with the control end of the corresponding high-power electronic switch through an audio square wave generator.
10. The cable fault prefixed point detecting device according to claim 7 or 8, characterized in that a current limiting resistor R2 or R3 is provided between said first dc power source (10) and a unidirectional conducting device VD1 or between the high power electronic switch and a unidirectional conducting device VD 5; wherein,
the resistor R2 is used for prolonging the existence time of the arc;
the resistor R3 is used to protect high power electronic switching devices.
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| CNB2005100126443A CN100410673C (en) | 2005-07-01 | 2005-07-01 | Cable failure prefixed point detection method and detection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101533049B (en) * | 2008-12-10 | 2011-04-06 | 北京航空航天大学 | Current radiation transmitting device for measuring cable |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5352984A (en) * | 1992-11-04 | 1994-10-04 | Cable Repair Systems Corporation | Fault and splice finding system and method |
| US5530365A (en) * | 1993-10-21 | 1996-06-25 | Hagenuk Gmbh | Process and apparatus for locating faults in cables, such as faults in underground cables |
| US6826770B2 (en) * | 2001-09-27 | 2004-11-30 | Funai Electric Co., Ltd. | Disk driving device with improved disk holding features |
| CN1588101A (en) * | 2004-09-30 | 2005-03-02 | 杨军 | Accurately positioning method and device for underground layered power cable defect position |
| CN1598607A (en) * | 2004-08-20 | 2005-03-23 | 淄博博鸿电气有限公司 | Directional and positioning testing device for fault of direct application type cable sheath |
-
2005
- 2005-07-01 CN CNB2005100126443A patent/CN100410673C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5352984A (en) * | 1992-11-04 | 1994-10-04 | Cable Repair Systems Corporation | Fault and splice finding system and method |
| US5530365A (en) * | 1993-10-21 | 1996-06-25 | Hagenuk Gmbh | Process and apparatus for locating faults in cables, such as faults in underground cables |
| US6826770B2 (en) * | 2001-09-27 | 2004-11-30 | Funai Electric Co., Ltd. | Disk driving device with improved disk holding features |
| CN1598607A (en) * | 2004-08-20 | 2005-03-23 | 淄博博鸿电气有限公司 | Directional and positioning testing device for fault of direct application type cable sheath |
| CN1588101A (en) * | 2004-09-30 | 2005-03-02 | 杨军 | Accurately positioning method and device for underground layered power cable defect position |
Non-Patent Citations (6)
| Title |
|---|
| 电力电缆故障探测技术的应用与效果分析. 孔祥辉，董正庆，王洋.大庆高等专科学校学报，第24卷第4期. 2004 |
| 电力电缆故障探测技术的应用与效果分析. 孔祥辉，董正庆，王洋.大庆高等专科学校学报，第24卷第4期. 2004 * |
| 电力电缆故障的测试技术及应用. 梁浩，任春明，任立强.山西电力，第5卷. 2003 |
| 电力电缆故障的测试技术及应用. 梁浩，任春明，任立强.山西电力，第5卷. 2003 * |
| 直埋电缆故障点的精测. 袁梅，袁长春.电力建设，第23卷第4期. 2002 |
| 直埋电缆故障点的精测. 袁梅，袁长春.电力建设，第23卷第4期. 2002 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101533049B (en) * | 2008-12-10 | 2011-04-06 | 北京航空航天大学 | Current radiation transmitting device for measuring cable |
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Assignee: Chengdu Kexin Electric Co., Ltd. Assignor: Zibo Weite Electric Co., Ltd. Contract fulfillment period: 2009.9.1 to 2014.8.31 contract change Contract record no.: 2009510000055 Denomination of invention: Cable failure prefixed point detection method and detection device Granted publication date: 20080813 License type: Exclusive license Record date: 2009.9.21 |
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