CN203479974U - High frequency current calibrating device applied to mining high-voltage cable partial discharge detection - Google Patents

Abstract

The utility model discloses a high-frequency current calibration device in partial discharge detection of high-voltage cables for mining, which mainly includes an insulating shell, a high-frequency current coil, a pulse controller and a rechargeable lithium battery. The device of the utility model can simulate partial discharge types such as internal discharge, surface discharge and corona discharge in high-voltage mine cables. The utility model is a high-frequency current calibration device in the detection of partial discharge of high-voltage mine cables, which is especially suitable for the calibration of partial discharge amount and identification of partial discharge types of high-voltage mine cables.

Description

A high-frequency current calibration device in partial discharge detection of mine-used high-voltage cables

【Technical field】

The utility model relates to the detection and positioning technology in the partial discharge detection of the mine high-voltage cable in the mine, in particular to a high-frequency current calibration device in the partial discharge detection of the mine high-voltage cable. the

【Background technique】

Cables in mine power equipment are key equipment for safe production of power transmission in coal mines, and are responsible for safe production. Statistics on accidents from 2005 to 2010 show that the death toll of direct electromechanical accidents ranks fifth, gas explosion accidents indirectly caused by electromechanical accidents account for 48.1% of the total number of gas accidents, and mine fire accidents indirectly caused by them account for 80% of the total number of fire accidents. In electromechanical accidents, high-voltage cable fires are the main cause of such accidents. In 2010, there were 5 major and particularly serious fire accidents in coal mines across the country that killed more than 10 people, of which 4 were electromechanical accidents, and the 4 accidents were all The aging cable is caused by fire. Therefore, research on the occurrence mechanism of insulation defects in mine power equipment is carried out, and then a state monitoring system for mine power equipment is developed, and early warning information is extracted to monitor the insulation status of mine power equipment. It is of great practical significance to ensure the safe use of electricity underground. the

At present, the live detection is mainly based on non-invasive partial discharge detection methods. Many methods have been invented at home and abroad to monitor the partial discharge of power cables, mainly including high-frequency current pulse method, ultrasonic method and ultra-high frequency method (Zheng Wendong. Experimental research on partial discharge location of XLPE cable accessories by multi-sensor joint detection technology [J]. 2011. Li Tianjie. Discussion on the selection technology of coal mine cables [J]. Science and Technology, 2013, (03): 294. Li Haiying, Li Xuan , Song Jiancheng. Safety early warning model of mine high-voltage cables based on radar diagram method[J]. Journal of China Coal Society, 2012, (11): 1941-1946. Feng Dewang, Liu Wenhu. Induction of mine cable sheath to electrical fast transient The influence of coupling[J].Journal of Taiyuan University of Technology,2012,(02):139-143 Zhang Junan. Joint detection of partial discharge of XLPE cable accessories by UHF and VHF[J]. J]. Shaanxi Coal, 2011, (01): 88-89+113.). the

However, it is found in production practice that there are still some problems in the mine cable partial discharge technology based on the high frequency current method. It mainly includes the type of partial discharge failure and the evaluation of the amount of partial discharge that did not occur in the device. As a result, the test data of various manufacturers are inconsistent, and it is difficult to compare and analyze the data. Therefore, designing a high-frequency current calibration device in the partial discharge detection of mine high-voltage cables can solve the above-mentioned problems faced in the partial discharge detection of mine high-voltage cables. the

【Content of utility model】

In order to achieve the above purpose, the utility model provides a high-frequency current calibration device in the detection of partial discharge of high-voltage cables for mines. Discharge type pulse train signal. the

The utility model adopts the following technical solutions:

A high-frequency current calibration device for partial discharge detection of mine-used high-voltage cables, including an insulating casing, a pulse controller and a high-frequency current coil are installed in the insulating casing, one end of the pulse controller is connected to a power supply, and the other One end is connected with the high-frequency current coil. the

As a preferred embodiment of the present invention, the power supply is a rechargeable lithium battery, which is connected to an external charger through a charging interface. the

As a preferred embodiment of the present utility model, the charging interface is a waterproof plug, and the protection level is IP65. the

As a preferred embodiment of the present invention, the high-frequency current coil is composed of a Rogowski coil with a drive signal input interface. the

The high-frequency current coil is mainly composed of a clamp-shaped shell, a magnetic core, a coil, an integrating resistor, a passive bandpass filter, a discharge tube, and a BNC connector; the coil is wound on the periphery of the magnetic core, and the magnetic core is arranged on the One end of the coil is drawn out from the clamp-shaped housing and connected to the BNC connector through a passive bandpass filter. The integrating resistor and discharge tube are connected in series at both ends of the BNC connector, and the integrating resistor and discharge tube are connected in series. The junction between the tubes is connected to the input of the passive bandpass filter. the

Described pulse controller is mainly made of FPGA, DAC and DDR2; One end of FPGA is connected with DDR2, and the other end is connected with DAC; The other end of described DAC is connected with the band driving signal input interface of high-frequency current coil through power amplifier, Output the signal to the high-frequency current coil. the

The FPGA selects EP4CE15 series chips. the

The coil is a Rogowski coil with an inner diameter of 8cm and a frequency band of 1kHz-5MHz. the

The coil adopts an air-core coil structure. the

The insulating shell is made of epoxy resin and can withstand a voltage of not less than 20kV. the

Compared with the prior art, the utility model has the following beneficial effects:

1. Both the shell of the transmitting coil and the shell of the main engine have the insulation level and explosion-proof requirements required by the mine site, which ensures the safety of the user when operating the instrument;

2. When conducting on-site monitoring, the operator only needs to install the clamp-type transceiver coil on the grounding wire of the cable, and the pulse signal of different intensities and frequencies can be transmitted through the pulse transmitting host, and the time difference between the transmitted pulse and the reflected pulse can be calculated accurately. Calculate the propagation velocity of the pulse in the cable; By calculating the amplitude difference between the transmitted pulse and the reflected pulse, the attenuation coefficient of the pulse can be accurately calculated when the pulse is transmitted along the cable, so that it can diagnose whether partial discharge occurs in the cable and locate the discharge point. the

【Description of drawings】

Fig. 1 is a structural schematic diagram of the high-frequency current calibration device in the partial discharge detection of the mine high-voltage cable of the utility model. the

Fig. 2 is a schematic diagram of the composition of the pulse controller of the high-frequency current calibration device in the partial discharge detection of the mine high-voltage cable of the utility model. the

Fig. 3 is a schematic diagram of the basic structure of the high-frequency current coil of the high-frequency current calibration device in the partial discharge detection of the mine high-voltage cable of the present invention. the

Among them, charging interface 11, rechargeable lithium battery 12, pulse controller 13, high-frequency current coil 14, insulating shell 15, field programmable gate array (FPGA) 21, high-speed digital-to-analog conversion chip (DAC) 22, high-speed memory (DDR2 ) 23. Clamp sensor housing 31 , magnetic core 32 , coil 33 , integrating resistor 34 , passive bandpass filter 35 , sensor discharge tube 36 , and BNC connector 37 . the

【Detailed ways】

The above is only an overview of the technical solution of the utility model. In order to understand the technical means of the utility model more clearly, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. the

The structure of the high-frequency current verification device in the partial discharge detection of the mine high-voltage cable of the utility model is shown in Fig. Device 13 and high-frequency current coil 14, wherein:

The charging interface 11 is a waterproof plug with a protection level of IP65. the

One end of the rechargeable lithium battery 12 is connected to an external charger through the charging interface 11 on the insulating casing 15 , and the other end of the rechargeable lithium battery 12 is connected to the pulse controller 13 to provide power for the pulse controller 13 . the

The high-frequency current coil 14 is composed of a Rogowski coil with a drive signal input interface. , Discharge tube 36, BNC joint 37 composition. The coil 33 is wound around the periphery of the magnetic core 32, the magnetic core 32 is arranged in the pincer shell 31, and one end of the coil is drawn from the pincer shell and connected to the BNC connector 37 through a passive bandpass filter 35 The integrating resistor 34 and the discharge tube 36 are connected in series to both ends of the BNC connector 37, and the node between the integrating resistor 34 and the discharge tube 36 is connected to the input terminal of the passive bandpass filter 35. the

The basic structure of described pulse controller 13 is referring to shown in Figure 2, and described pulse controller 13 is fixed in the insulating shell 15, mainly is made of field programmable gate array FPGA21, high-speed digital-to-analog conversion chip DAC22 and high-speed memory DDR223. Field programmable gate array FPGA21 produces various discharge data; One end of field programmable gate array FPGA21 is connected with large-capacity high-speed memory 23, discharge data is stored in large-capacity high-speed memory 23, the other end of field programmable gate array FPGA21 It is connected to one end of the high-speed digital-to-analog conversion chip DAC22; the other end of the high-speed digital-to-analog conversion chip DAC22 is connected to the input interface with a driving signal of the high-frequency current coil 14 through a power amplifier, and outputs the signal to the high-frequency current coil 14. the

The above field programmable gate array FPGA uses EP4CE15 series chips from ALTERA Company, which can support DDR2 memory interface, and input and output interfaces support logic level devices such as 1.5-V, 1.8-V, 2.5-V and 3.3-V. the

The above-mentioned coil 14 is a Rogowski coil with an inner diameter of 8cm and a frequency band of 1kHz-5MHz. It adopts a hollow coil structure, and the coil material is a high-frequency material. the

The above-mentioned insulating shell 15 is made of epoxy resin, which can withstand a voltage of not less than 20kV. the

The high-frequency current calibration device in the partial discharge detection of mine high-voltage cables of the utility model is used in the following two aspects:

1. Calibrate the discharge amount of the ground wave signal:

The user can adjust the output strength of the ground wave signal through the high-speed digital-to-analog conversion chip (DAC) in the device. There are multiple levels of signal output strength, and each level corresponds to a different discharge capacity. Therefore, the discharge capacity can be calibrated by using the discharge capacity of the output signal. the

2. Identify the discharge pattern detected by the ground wave:

Various types of discharge signals are generated by using the discharge type data stored in the large-capacity memory of the device. The characteristics of each discharge type signal are different, and the discharge mode can be judged according to the characteristic signal detected by the ground wave sensor. the

The utility model has the following advantages: 1. The partial discharge signal pattern of the utility model can be stored to ensure the accuracy and repeatability of the partial discharge signal pattern. 2. When the utility model is used on site, the operator only needs to clamp the simulation device to the cable, and then use the high-frequency current sensor to collect data at the cable, so as to realize the calibration of the discharge amount and the identification of the discharge mode. the

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model in any form. Those skilled in the art can use the technical content disclosed above to make some simple modifications, equivalent changes or modifications, all of which fall within the protection scope of the present invention. the

Claims (10)

1. the high-frequency current calibration equipment in a mine high-voltage cable Partial Discharge Detection, it is characterized in that, comprise insulation crust (15), impulse controller (13) and high-frequency current coil (14) are installed in described insulation crust (15), one end of described impulse controller is connected with power supply, and the other end is connected with high-frequency current coil.

2. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 1, is characterized in that: described power supply is charged lithium cells (12), and this charged lithium cells is connected with outside charger by charging inlet (11).

3. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 2, is characterized in that: described charging inlet (11) is waterproof plug, and degree of protection is IP65.

4. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 1, is characterized in that: described high-frequency current coil (14) drives the Rogowsky coil of signal input interface to form by band.

5. the high-frequency current calibration equipment in the mine high-voltage cable Partial Discharge Detection as described in claim 1 or 4, is characterized in that: described high-frequency current coil (14) is mainly comprised of pincerlike shell (31), magnetic core (32), coil (33), integrating resistor (34), passive bandpass filters (35), discharge tube (36), BNC connector (37); Described coil (33) is wrapped in magnetic core (32) periphery, described magnetic core (32) is arranged in pincerlike shell (31), an end of described coil is drawn and is passed through passive bandpass filters (35) from pincerlike shell and is connected with BNC connector (37), after described integrating resistor (34) and discharge tube (36) series connection, be connected to BNC connector (37) two ends, and the node between integrating resistor (34) and discharge tube (36) is connected with the input end of passive bandpass filters (35).

6. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 1, is characterized in that: described impulse controller (13) is mainly by FPGA(21), DAC(22) and DDR2(23) form; FPGA(21) one end is connected with DDR2, the other end and DAC(22) be connected; Described DAC(22) the other end drives signal input interface to be connected by power amplifier with the band of high-frequency current coil (14), and signal is outputed to high-frequency current coil (14).

7. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 6, is characterized in that: described FPGA selects EP4CE15 family chip.

8. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 5, is characterized in that: described coil (14) is Rogowsky coil, and internal diameter is 8cm, and frequency band is 1kHz-5MHz.

9. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 8, is characterized in that: described coil (14) adopts air core coil structure.

10. the high-frequency current calibration equipment in mine high-voltage cable Partial Discharge Detection as claimed in claim 1, is characterized in that: described insulation crust (15) is epoxy resin material, and tolerance is not less than 20kV voltage.

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