CN103985298B - A kind of cable fault simulation, alignment system - Google Patents

Abstract

The invention relates to a cable fault simulation and positioning system, comprising: a cable fault simulation box, an electrode mounting plate arranged in the cable fault simulation box, three incoming wire electrodes and three outgoing wire electrodes; The three-phase cores in the cable are connected, and the three outgoing electrodes are respectively connected to the three-phase cores in the outgoing cable; the cable fault simulation box is equipped with a circuit for simulating disconnection, low resistance, The resistance box for high-resistance and flashover faults, the end of the outgoing cable connected to the outgoing electrode is equipped with a high-voltage cable terminal; the high-voltage cable terminal is used to connect the cable fault location detector. The cable fault location detector includes: a central control unit, a pulse transmitting circuit for transmitting pulse signals to the tested cable, a reflection receiving circuit and a high-speed data acquisition circuit for receiving reflected signals from the tested cable; the reflection receiving circuit The output end is connected with the input end of the high-speed data acquisition circuit.

Description

A cable fault simulation and location system

This application is a divisional application of the invention patent application with the application number: 200910309789.8, the invention name is "Cable Fault Simulation and Fault Location System", and the application date is: November 16, 2009.

technical field

The invention relates to the technical field of cable fault simulation equipment for personnel training, in particular to a cable fault simulation and fault location system for personnel training.

Background technique

Power cables (hereinafter referred to as cables) are mostly buried underground. Once a fault occurs, it is very difficult to find it. It often takes hours or even days, which not only wastes a lot of manpower and material resources, but also causes a lot of power loss and bad social impact. How to accurately, quickly and economically find the cable fault point has become a problem that the power supply department pays more and more attention to. The cable fault situation and the embedment environment are more complicated and varied. Testers should be familiar with the cable burial direction and environment, accurately determine the nature of the cable fault, select appropriate instruments and measurement methods, and work in accordance with certain procedures to successfully test Cable fault point.

In recent years, the testing technology for power cable faults has made great progress, such as the pulse time domain reflection method for fault location, the pulse magnetic field method for path detection, and the method of using the time difference between the magnetic field and the sound signal to find the location of the fault point, etc. The application of computer technology has brought a new look to the cable fault detection technology and entered the stage of intelligence.

Power cable fault detection is a highly technical job, and testers should master the working principles of the instruments used and have certain work experience. To do a good job in the detection of cable faults, in addition to purchasing advanced instruments and equipment, it is also necessary to do a good job in the training of testers.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cable fault simulation and fault location system for personnel training.

In order to solve the above-mentioned technical problems, the present invention provides a cable fault simulation and positioning system, comprising: a cable fault simulation box, an electrode mounting plate located in the cable fault simulation box, and three incoming wires located on the electrode mounting plate electrodes and three outgoing electrodes; the three incoming electrodes are respectively connected to the three-phase cores in the incoming cables, and the three outgoing electrodes are respectively connected to the three-phase cores in the outgoing cables; the cable fault simulation box is equipped with A resistance box for simulating disconnection faults, low-resistance faults, high-resistance faults and flashover faults between the incoming and outgoing electrodes, the end of the outgoing cable connected to the outgoing electrodes is provided with a high-voltage cable terminal; For connecting cable fault location detectors. The cable fault location detector includes: a central control unit, a pulse transmitting circuit connected to the central control unit for transmitting a pulse signal to the cable under test, a reflection receiving circuit for receiving a reflected signal from the cable under test, and A high-speed data acquisition circuit connected to the data acquisition input end of the central control unit; an output end of the reflection receiving circuit connected to an input end of the high-speed data acquisition circuit.

The cable fault simulation box is provided with a monitor connected to the insulators on each incoming line electrode and each outgoing line electrode for monitoring the voltage status of each incoming line electrode and each outgoing line electrode.

The pulse transmitting circuit includes: a timer connected to the preset and start signal output terminals of the central control unit, an amplifying circuit connected to the output terminal of the timer, a pulse transformer connected to the output terminal of the amplifying circuit, and a pulse transformer connected to the output terminal of the pulse transformer. Coupled coupling transformer, and internal impedance balancing circuit; the first secondary coil of the pulse transformer, the first primary coil of the coupling transformer and the internal impedance balancing circuit form a loop; the second secondary coil of the pulse transformer, the second primary coil of the coupling transformer The coil and the cable under test form a loop; the secondary coil of the coupling transformer and the reflection receiving circuit.

Further, in order to facilitate the use of a resistance box to directly set various faults between the incoming electrode and the outgoing electrode and ensure safe operation, the incoming electrode and the outgoing electrode are insulated cones, and the end is provided inside it through the electrode mounting plate. The electrode rod of the mounting hole; the end of the electrode rod is used to connect the cable core wire and wrap it with insulating material, the bottom of the insulating cone extends into the mounting hole on the electrode mounting plate, and the front end of the electrode rod extends out of the top of the insulating cone , the front end of the electrode rod is connected with a bolt.

Positive effects of the present invention: (1) In the present invention, three incoming electrodes and three outgoing electrodes are set in the cable fault simulation box. The change of the resistance value between them, as well as the change of the connection between the phase line and the ground, simulate various cable faults, and then use the cable fault detector to detect, so as to meet the requirements of personnel training. (2) The monitor is used to monitor the voltage state to facilitate debugging. (3) The cable fault detector adopts the method of pulse signal transmission and reception to detect the type of cable fault, and realize fault distance measurement or location. It has a simple structure and is easy to use. (4) The present invention has the following characteristics: 1). High degree of intelligence. It can automatically judge whether the fault point is discharged, calculate and display the fault distance; it has functions such as waveform storage, comparison, amplification and operation prompt; it can also adjust the wave speed according to different cable insulation media; it provides two movable cursors, which can measure the waveform on the The distance between any two points. 2). Using a linear current coupler to measure the pulse current signal flowing through the ground wire, compared with the traditional flash tester using a resistor-capacitor voltage divider to measure pulse voltage signals, the wiring is simple and convenient; the instrument and the high-voltage circuit are separated from the Electrically isolated, the safety is particularly good. 3). Powered by rechargeable batteries, small in size, light in weight and easy to carry. It avoids the interference problem caused by sharing the AC power with the high-voltage circuit in the traditional flash tester, and ensures that the instrument can work reliably when the ball gap of the high-voltage circuit breaks down or the fault point discharges in a strong electromagnetic interference environment. 4). Using a large-screen dot-matrix liquid crystal display, the displayed information such as waveforms and fault distances is stable and clear. The contrast can be adjusted, and it has a backlight function to obtain the best display effect under different external light conditions. 5). The measurement accuracy is high. When the measured cable length is less than 1000m, the absolute error is less than ±1m; when the cable length is greater than 1000m, the relative error is less than 0.5%. 6). The measurement blind area is small, and the fault at the first 10m of the cable can be detected. 7). Equipped with a micro-printer interface, it can easily print out the waveform, data and other information displayed on the screen, which is convenient for saving data.

Description of drawings

In order to make the content of the present invention more easily understood, the present invention will be described in further detail below in conjunction with the specific embodiments according to the accompanying drawings, wherein

Fig. 1 is the front view of cable fault simulation, positioning system in the embodiment;

Fig. 2 is the side view of Fig. 1;

Fig. 3 is the structural representation at the bottom of the cable fault simulation and positioning system in the embodiment;

Fig. 4 is the cable fault simulation in the embodiment, the assembly structure schematic diagram of the electrode mounting plate, the incoming line electrode and the outgoing line electrode in the positioning system;

Fig. 5 is the structural representation of outgoing cable and high-voltage cable terminal in the embodiment;

Fig. 6 is the structural representation of the incoming line electrode and the outgoing line electrode in the embodiment;

Fig. 7 is the B-B sectional view of Fig. 6;

Fig. 8 is the circuit block diagram of the cable fault location detector in the embodiment;

FIG. 9 is a circuit block diagram of the pulse transmitting circuit in FIG. 8 .

detailed description

See Figures 1-9, the cable fault simulation and positioning system of this embodiment includes: a cable fault simulation box 1 located on the concrete foundation 2, an electrode mounting plate 5 located in the cable fault simulation box 1, and an electrode mounting plate Three incoming electrodes 6 and three outgoing electrodes 7 on the board 5; the three incoming electrodes 6 are respectively connected to the three-phase cores in the incoming cable 8, and the three outgoing electrodes 7 are respectively connected to the three phase cores in the outgoing cable 9. The phase cores are connected. The reinforced concrete foundation 2 is fixedly connected with the cable fault simulation box 1 through foundation feet and expansion bolts. Both sides of the bottom of the cable fault simulation box 1 are provided with threading pipes 3, the center of the bottom of the cable fault simulation box 1 has an opening 4, and the front end of the cable fault simulation box 1 is provided with double doors 14.

The insulator outer shielding of the incoming cable 8 and the outgoing cable 9 is grounded. The cable fault simulation box 1 is provided with a resistance box 10 for simulating disconnection faults, low-resistance faults, high-resistance faults and flashover faults between the incoming electrode 6 and the outgoing electrode 7 .

The cable fault simulation box 1 is provided with a monitor 11 connected to the insulators on each incoming line electrode 6 and each outgoing line electrode 7 for monitoring the voltage status of each incoming line electrode 6 and each outgoing line electrode 7 .

A high voltage cable terminal 12 is provided at the end of the outgoing cable 13 connected to the outgoing electrode 7 .

After a certain fault is set in the cable fault simulation and positioning system, the fault detection is performed through the cable fault detection and locator connected to the high-voltage cable terminal 12, which is convenient and safe to use, and has good practicality.

The incoming electrode 6 and the outgoing electrode 7 are insulated cones, which are provided with an electrode rod b whose end passes through the mounting hole on the electrode mounting plate 5; the end of the electrode rod b is used to connect the cable core wire d and use an insulating material ePacket. The bottom of the insulating cone extends into the mounting hole on the electrode mounting plate 5 . The front end of the electrode rod b extends out from the top of the insulating cone a, and the front end of the electrode rod b is connected with a bolt c. The insulating material e is connected with a ground wire.

The cable fault location detector includes: a central control unit 30, a pulse transmitting circuit 31 connected to the central control unit 30 for transmitting pulse signals to the cable under test, and a reflection receiving circuit for receiving reflected signals from the cable under test 32 , and a high-speed data acquisition circuit 33 connected to the data acquisition input end of the central control unit 30 ; the output end of the reflection receiving circuit 32 is connected to the input end of the high-speed data acquisition circuit 33 .

The central control unit 30 is also connected with a printer 34 , an LCD 35 and a keyboard 36 .

The pulse transmission circuit 31 includes: a timer 21 connected to the preset and start signal output of the central control unit 30, an amplifying circuit 22 connected to the output of the timer 21, a pulse connected to the output of the amplifying circuit 22 The transformer T1, the coupling transformer T2 coupled with the pulse transformer T1, and the internal impedance balance circuit 23; the first secondary coil L3 of the pulse transformer T1, the first primary coil L5 of the coupling transformer T2 and the internal impedance balance circuit 23 form a loop; The second secondary coil L2 of the pulse transformer T1 , the second primary coil L4 of the coupling transformer T2 and the cable under test form a loop; the secondary coil L6 of the coupling transformer T2 is connected to the reflection receiving circuit 32 .

The cable fault location detector has two working modes of low-voltage pulse reflection and pulse current. The low-voltage pulse reflection working mode is used to detect low resistance and disconnection faults of cables, and to measure the length or wave velocity of various cables. The pulse current working mode is used for high-resistance and flashover fault location of cables.

The function of the central control unit 30 is: to receive key input instructions and perform corresponding operations; take out the recorded pulse reflection waveform or pulse current data of fault point discharge from the high-speed data acquisition circuit 33 for processing; and other information are sent to LCD35 for display; self-inspection and monitoring of the entire system.

LCD35 is the output port of waveform, operation result or operation information.

The printer 34 is used to print out the information on the liquid crystal LCD35.

The pulse transmitting circuit 31 is used to generate a 30V rectangular pulse with a predetermined width and send it to the cable through the coupling transformer T2. The timer 21 is a down counter that can be preset. The central control unit 30 presets a number to the timer, and the pulse transmission circuit 31 outputs a 5V level after receiving the command to start transmission from the central control unit 30. At this time, the timer 21 performs subtraction under the control of the clock signal. Counting, that is, every time a clock pulse comes, the timing counter is decremented by 1. After several pulses, the counter is decremented to 0, and the timer 21 outputs a 0V level, thus forming a 5V rectangular pulse with a certain width. If the preset value is changed according to the measurement range, the timer will output pulses with different widths.

The 5V rectangular pulse output by the timer 21 is amplified into a 30V voltage pulse by the amplifying circuit 22, and applied to the primary coil L1 of the pulse transformer T1, and the same size and opposite polarity are generated on the coils L2 and L3 of the pulse transformer T1. The voltage pulses are added to the tested circuit and the internal impedance balance circuit 23 respectively. If the impedance of the internal balanced circuit is similar to the wave impedance of the tested circuit, under the action of the transmitted pulse, the coils L4 and L5 of the coupling transformer T2 A current signal with similar magnitude and opposite polarity is generated, and the signal received by L6 is extremely weak, achieving the purpose of compressing the emission pulse. And when the reflected pulse on the cable under test arrives, the voltages generated on the coils L3 and L5 are equal in size and opposite in direction, the algebraic sum of the loop voltage is 0, the internal balance circuit does not work, and the reflected pulse voltage passes through the coupling transformer T2 The second primary coil L4 is completely converted to the secondary coil L6, which is added to the signal receiving circuit.

The reflection receiving circuit 32 is used to receive and amplify the signal from the secondary coil L6 of the coupling transformer, and the amplification gain can be adjusted. In the pulse current working mode, the pulse current signal from the linear current coupler is completely converted to the secondary coil L6 through L4 of the coupling transformer T2;

The high-speed data acquisition circuit 33 samples the analog signal at a certain frequency and converts the extracted amplitude into a digital value for storage, and records pulse reflection or pulse current waveform. If the ranging resolution of 1m is to be realized, the time resolution of waveform sampling is required to be about 10ns, and the corresponding data acquisition frequency is 100MHz. The clock frequency of general central control unit 30 is only ten megahertz, it is difficult to directly control the A/D (analog quantity/digital quantity) conversion and storage of signal. The device designs a unique ultra-high-speed 100MHz data acquisition circuit, which automatically completes the sampling and conversion of the pulse reflection waveform and temporarily stores it in a data buffer without the interference of the central control unit 30 . After one waveform recording is completed, the central control unit 30 takes out the pulse reflection or pulse current waveform data in the data buffer through the interface circuit for processing.

The above-mentioned embodiments are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here.

Claims (1)

1. a cable fault simulation, alignment system, it is characterised in that including: cable fault simulation box (1), the electrode installing plate (5) being located in cable fault simulation box (1) and be located at three inlet wire electrodes (6) on electrode installing plate (5) and three go out line electrode (7); Three inlet wire electrodes (6) are connected with the three-phase core in inlet wire cable (8) respectively, and three go out line electrode (7) and are connected with the three-phase core in outlet cable respectively; Be provided with at inlet wire electrode (6) with go out the resistance box (10) simulating disconnection fault, low resistance faults, high resistive fault and arcing fault between line electrode (7) in described cable fault simulation box (1), with described go out the end of outlet cable that is connected of line electrode (7) be provided with hv cable termination (12);Hv cable termination (12) is used for connecting cable fault positioning detector;

This cable fault positioning detector includes: what central control unit (30) was connected with central control unit (30) is used for launching the impulse ejection circuit (31) of pulse signal to tested cable, being used for the reflection receivable circuit (32) receiving the reflected signal from described tested cable and the High Speed Data Acquisition Circuit (33) being connected with the data acquisition input of central control unit (30); The outfan of reflection receivable circuit (32) is connected with the input of High Speed Data Acquisition Circuit (33);

It is provided with being used for of being connected with each inlet wire electrode (6) and the insulator that respectively goes out on line electrode (7) in described cable fault simulation box (1) monitor each inlet wire electrode (6) and respectively go out the monitor (11) of voltage status of line electrode (7);

Described impulse ejection circuit (31) including: pulse transformer (T1) that the amplifying circuit (22) that the intervalometer (21) being respectively connected with the enabling signal outfan of the preset outfan of central control unit (30) and central control unit (30) is connected with the outfan of intervalometer (21) is connected with the outfan of amplifying circuit (22) and the coupling transformer (T2) that pulse transformer (T1) is coupled and internal driving balancing circuitry (23); First secondary coil (L3) of pulse transformer (T1), first primary coil (L5) of coupling transformer (T2) and internal driving balancing circuitry (23) constitute loop; The second subprime coil (L2) of pulse transformer (T1), second primary coil (L4) of coupling transformer (T2) and tested cable constitute loop; The secondary coil (L6) of coupling transformer (T2) is connected with reflection receivable circuit (32).