CN203101575U - Short-circuit fault line selection device for borehole cable - Google Patents

Abstract

The utility model discloses a short-circuit fault line selection device for a borehole cable. The short-circuit fault line selection device comprises a current signal generating circuit module, a plurality of current transformers, a plurality of signal conditioning circuit modules and a data processing display circuit module, wherein the current signal generating circuit module is composed of a sinusoidal signal generator and a voltage transformer; the current transformers are sleeved on a grounding wire of an outgoing cable; each single conditioning circuit module is composed of a lowpass filtering circuit module, a twin-T network wave trap module and an amplifying circuit module, which are connected in sequence; and the data processing display circuit module comprises an A/D (Analog/Digital) switching circuit module, a microprocessor module, a communication circuit module and an upper computer, which are connected in sequence. The short-circuit fault line selection device is simple in structure, reasonable in design, convenient to implement, low in cost, high in working reliability, strong in practicability and convenient to popularize and use, can be used for carrying out line selection on a short-circuit fault when a cable line operates and timely and accurately discovering a fault line and has a good use effect.

Description

A line selection device for mine cable short circuit fault

technical field

The utility model relates to the technical field of cable fault diagnosis, in particular to a mine cable short-circuit fault line selection device.

Background technique

Whether it is the arc generated by the fault of the cable itself or the fire in the external environment of the cable, it will directly cause the cable to catch fire. For the special industry of coal mine, the consequences will directly endanger the safety of underground workers. In the final analysis, the fault of the cable itself is the decline of insulation, aging and even destruction. After long-term operation of the cable, or overload operation, and when the protection device cannot cut off the short-circuit current in time, the long-term heating will cause its insulation performance to decline, and the long-term action will eventually cause the short-circuit of the cable to catch fire and bring serious consequences. It is necessary to design an effective online line selection device for the short-circuit fault caused by the insulation drop of underground cables.

At present, the underground cable power supply line still uses an insulation detection device with an additional DC power supply. This device can only detect the change of the insulation resistance of the cable line to the ground. For the cable line, the capacitive effect is its outstanding performance, and the additional DC power supply insulation detection device cannot. It fully reflects the insulation level of the cable line in the AC state, and the fault current is capacitive when the cable line has a short-circuit fault, so the additional DC power supply insulation detection device cannot realize fault line selection. Secondly, at present, the insulation resistance tester used in the regular maintenance of cable lines in the underground is for offline detection, so that the equipment cannot be used to determine the faulty line in time when a short-circuit fault occurs in the cable during operation. To sum up, for mine cables in operation, it is urgent to design and implement a practical mine cable short-circuit fault line selection device.

Utility model content

The technical problem to be solved by the utility model is to provide a line selection device for mine cable short-circuit fault, which is simple in structure, reasonable in design, convenient to realize and low in cost, high in working reliability, and can be timely and accurately The utility model has the advantages of strong practicability, good use effect and convenient popularization and use for finding fault lines.

In order to solve the above-mentioned technical problems, the technical solution adopted by the utility model is: a line selection device for mine cable short-circuit fault, which is characterized in that it includes a current signal generating circuit module for generating a 25Hz sinusoidal current signal and injecting it into the short-circuit fault phase and respectively A plurality of current transformers used to obtain the current flowing through the grounding wires of the plurality of outgoing cables, and a plurality of signal conditioning circuit modules connected to the plurality of current transformers and a plurality of signal conditioning circuit modules connected to the plurality of signal conditioning circuit modules respectively Data processing display circuit module; the current signal generating circuit module is composed of a sinusoidal signal generator and a voltage transformer, and the terminal A, terminal B and terminal C of the primary side coil of the voltage transformer are all grounded through a resistor R, And respectively corresponding to the A-phase line, B-phase line and C-phase line of the busbar, the terminal a, terminal b and terminal c of the secondary side coil of the voltage transformer are connected in a star shape and respectively connected to the sinusoidal signal The output channel A, output channel B and output channel C of the generator are connected, the neutral point n of the secondary side coil of the voltage transformer is connected with the neutral terminal N of the sinusoidal signal generator, and the current transformer is set in the outgoing line On the cable grounding line, the signal conditioning circuit module consists of a low-pass filter circuit module connected in sequence and used to filter out AC signals above 100 Hz, and a double-T network wave limiting circuit module used to filter out 50 Hz power frequency signals and an amplifying circuit module for amplifying signals; the data processing and display circuit module includes an A/D conversion circuit module connected with the amplifying circuit module and a microprocessor module connected with the A/D conversion circuit module, And the communication circuit module connected with the microprocessor module and the host computer connected with the communication circuit module.

The above-mentioned line selection device for mine cable short-circuit fault is characterized in that the current transformer is a split current transformer.

The above-mentioned line selection device for mine cable short-circuit fault is characterized in that: the microprocessor module is a DSP digital signal processor, and the A/D conversion circuit module is integrated inside the DSP digital signal processor.

The above-mentioned line selection device for mine cable short-circuit fault is characterized in that: the DSP digital signal processor is a chip TMS320F2812.

The above-mentioned line selection device for mine cable short-circuit fault is characterized in that: the communication circuit module is a serial port communication circuit module or a USB interface communication circuit module.

Compared with the prior art, the utility model has the following advantages:

1. This utility model is designed for the special operation mode of the underground, meets the safety requirements of the underground use, adopts a modular design, and at the same time makes full use of the inherent grounding wire structure of the outgoing cable itself. The structure is simple, the design is reasonable, and the realization of Convenient and low cost.

2. The utility model adopts a split-type current transformer to obtain the cable grounding current, and the split-type current transformer directly outputs a voltage signal of 0.333V to 3.53V, which can be directly used as the input signal of the microprocessor module after signal conditioning, eliminating the need for The sampling resistor link is eliminated, and when in use, only the two semi-circular rings of the current transformer are clamped on the grounding wire of the outgoing cable, which is convenient for installation and low in measurement cost.

3. The utility model adopts the dual-T network wave limiting circuit module to complete the filtering of 50Hz power frequency signal, and the circuit structure is simple and easy to realize.

4. The microprocessor module of the utility model adopts a DSP digital signal processor, which realizes the signal processing of the fault line selection function, fully exerts the digital computing ability of the DSP digital signal processor, and has high working reliability.

5. Due to the obvious difference between the fault line and the non-fault line ground wire current in practice, the accuracy requirements for the A/D conversion circuit module are not high. The utility model adopts the A/D integrated in the DSP digital signal processor. The conversion circuit module performs analog-to-digital conversion, the circuit structure is simple, the implementation cost is low, and the accuracy requirement is met.

6. The utility model can correctly reflect the insulation level of the cable line in the AC state, can select the line for the short-circuit fault of the cable line in operation, can find the faulty line in time and accurately, and cooperate with the actuator to deal with the faulty line to avoid accidents Expand further.

7. The utility model has strong practicability, good use effect, and is convenient for popularization and use.

To sum up, the utility model has the advantages of simple structure, reasonable design, convenient implementation, low cost, high working reliability, timely and accurate detection of fault lines, strong practicability, good use effect, and easy popularization and use.

The technical solutions of the present utility model will be further described in detail through the drawings and embodiments below.

Description of drawings

Fig. 1 is the block diagram of circuit principle of the utility model.

Explanation of reference signs:

1-1-sine signal generator; 1-2-voltage transformer; 2-current transformer;

3-1-Low-pass filter circuit module; 3-2-Double T network wave limiting circuit module;

3-3-amplification circuit module; 4-1-A/D conversion circuit module;

4-2-microprocessor module; 4-3-communication circuit module; 4-4-host computer;

5- three-phase AC power supply; 6- load.

Detailed ways

As shown in Figure 1, the utility model includes a current signal generating circuit module for generating a 25Hz sinusoidal current signal and injecting it into the short-circuit fault phase, and a plurality of current transformers 2 respectively used to obtain the current flowing through the grounding wire of a plurality of outlet cables , and respectively correspond to a plurality of signal conditioning circuit modules connected with a plurality of current transformers 2 and a data processing display circuit module connected with a plurality of signal conditioning circuit modules; the current signal generation circuit module is composed of a sinusoidal signal generator 1-1 and a voltage transformer 1-2, the terminal A, terminal B and terminal C of the primary side coil of the voltage transformer 1-2 are all grounded through the resistor R, and respectively correspond to the A-phase line of the bus bar , B-phase line and C-phase line are connected, and the connection terminal a, connection terminal b and connection terminal c of the secondary side coil of the voltage transformer 1-2 are connected into a star shape and respectively connected with the sinusoidal signal generator 1-1 The output channel A, the output channel B and the output channel C are connected, and the neutral point n of the secondary side coil of the voltage transformer 1-2 is connected with the neutral terminal N of the sinusoidal signal generator 1-1, and the current transformer 2 Set on the grounding wire of the outgoing cable, the signal conditioning circuit module consists of a low-pass filter circuit module 3-1 connected in sequence and used to filter AC signals above 100Hz, and a low-pass filter circuit module 3-1 used to filter 50Hz power frequency signals The double-T network wave-limiting circuit module 3-2 and the amplifying circuit module 3-3 for amplifying the signal are composed; the data processing and display circuit module includes an A/D conversion circuit module connected with the amplifying circuit module 3-3 4-1 and the microprocessor module 4-2 connected with the A/D conversion circuit module 4-1, and the communication circuit module 4-3 connected with the microprocessor module 4-2 and the communication circuit module 4-2 3 connected host computers 4-4.

Wherein, the terminal A, terminal B and terminal C of the primary side coil of the voltage transformer 1-2 are all grounded through the resistor R, following the non-effectively grounded underground operation mode stipulated in the Coal Mine Safety Regulations.

In this embodiment, the current transformer 2 is a switchable current transformer, which directly outputs a voltage signal of 0.333V to 3.53V, and can be directly used as the input signal of the microprocessor module 4-2 after signal conditioning, eliminating the need for The sampling resistor link, and when in use, only need to clamp the two semi-circular rings of the current transformer 2 on the grounding wire of the outgoing cable, which is convenient for installation and low in measurement cost. The microprocessor module 4-2 is a DSP digital signal processor, and the A/D conversion circuit module 4-1 is integrated inside the DSP digital signal processor. The DSP digital signal processor is a chip TMS320F2812. The communication circuit module 4-3 is a serial port communication circuit module or a USB interface communication circuit module.

As shown in Figure 1, in the present embodiment, the quantity of described outlet cable is two and is respectively cable L1 and cable L2; The output terminals of are all connected with load 6.

The utility model is a line selection device for single-phase short-circuit faults caused by insulation aging of mine cables, and realizes the line selection function on the premise of specifying the fault phase. The working principle and working process of the utility model are: the sinusoidal signal generator 1-1 fixedly sends out a sinusoidal current signal with a frequency of 25Hz, and utilizes the voltage transformer 1-2 at the busbar to inject a 25Hz sinusoidal current signal into the short-circuit fault phase, each The current transformer 2 set on the grounding wire of each outgoing cable samples the output voltage signal of the current flowing through the grounding wire of each outgoing cable. First, the harmonic signal above 100 Hz is filtered out by the low-pass filter circuit module 3-1, and then passed through the double The T network wave limiting circuit module 3-2 filters out the 50Hz power frequency signal. At this time, the remaining signal only contains a 25Hz sinusoidal voltage signal, and then the injected 25Hz sinusoidal current signal is amplified by the amplifier circuit module 3-3 before transmission. For the A/D conversion circuit module 4-1, the microprocessor module 4-2 collects the signals output by a plurality of signal conditioning circuit modules through the A/D conversion circuit module 4-1, and the signal amplitude output by each signal conditioning circuit module Values are compared, and the outgoing cable corresponding to the larger amplitude is the faulty line, which realizes the line selection function, and the microprocessor module 4-2 uploads the line selection result to the host computer 4-4 through the communication circuit module 4-3, The host computer 4-4 displays the line selection result.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present utility model still belong to Within the scope of protection of the technical solution of the utility model.

Claims (5)

1. borehole cable short trouble line selection apparatus, it is characterized in that: comprise being used to the current signal generative circuit module that produces the 25Hz sinusoidal current signal and inject the short trouble phase and being respectively applied for a plurality of current transformers (2) that obtain the electric current of flowing through on the many outlet cable grounding lines, and corresponding respectively and a plurality of signal conditioning circuit modules that a plurality of current transformers (2) join and the data processing display circuit module of all joining with a plurality of signal conditioning circuit modules; Described current signal generative circuit module is made of sinusoidal signal generator (1-1) and voltage transformer (VT) (1-2), the connection terminal A of described voltage transformer (VT) (1-2) first siding ring, connection terminal B and connection terminal C are all by resistance R ground connection, and A phase line corresponding respectively and bus, B phase line and C phase line are joined, the connection terminal a of described voltage transformer (VT) (1-2) second siding ring, connection terminal b and connection terminal c be connected into star-like after respectively with the output channel A of sinusoidal signal generator (1-1), output channel B is connected with output channel C, the neutral point n of described voltage transformer (VT) (1-2) second siding ring is connected with the zero line side N of sinusoidal signal generator (1-1), described current transformer (2) is sleeved on the outlet cable grounding line, and described signal conditioning circuit module is by joining successively and being used for low-pass filter circuit module (3-1) with the AC signal filtering more than the 100Hz, be used for the twin-T network notch circuit module (3-2) of 50Hz power frequency component filtering and the amplifying circuit module (3-3) that is used for signal is amplified are constituted; Described data processing display circuit module comprises A/D change-over circuit module (4-1) of joining with amplifying circuit module (3-3) and the microprocessor module (4-2) that joins with A/D change-over circuit module (4-1), and communication circuit module (4-3) that joins with microprocessor module (4-2) and the host computer (4-4) that joins with communication circuit module (4-3).

2. according to the described a kind of borehole cable short trouble line selection apparatus of claim 1, it is characterized in that: described current transformer (2) is an open-close type current transformer.

3. according to the described a kind of borehole cable short trouble line selection apparatus of claim 1, it is characterized in that: described microprocessor module (4-2) is the DSP digital signal processor, and described A/D change-over circuit module (4-1) is integrated in described DSP digital signal processor inside.

4. according to the described a kind of borehole cable short trouble line selection apparatus of claim 3, it is characterized in that: described DSP digital signal processor is a chip TMS 320 F 2812.

5. according to the described a kind of borehole cable short trouble line selection apparatus of claim 1, it is characterized in that: described communication circuit module (4-3) is serial communication circuit module or USB interface communication circuit module.