CN212808479U

CN212808479U - Electrified fault diagnosis device of low-voltage transformer area zero line

Info

Publication number: CN212808479U
Application number: CN202021005519.6U
Authority: CN
Inventors: 何森; 伍振园; 虞浩文; 廖文翔; 周弘之; 黄辉; 曹青; 郭振炎
Original assignee: Guilin Power Supply Bureau of Guangxi Power Grid Co Ltd
Current assignee: Guilin Power Supply Bureau of Guangxi Power Grid Co Ltd
Priority date: 2020-06-04
Filing date: 2020-06-04
Publication date: 2021-03-26
Anticipated expiration: 2030-06-04

Abstract

The utility model discloses a low-voltage transformer area zero line live fault diagnosis device, which comprises a sensor module, a signal preprocessing circuit, a data acquisition and processing module, a wireless transmission module and a man-machine interaction module; the sensor module, the signal preprocessing circuit and the data acquisition and processing module are sequentially connected; the data acquisition and processing module is in data transmission with the man-machine interaction module through the wireless transmission module. The utility model discloses an introduce the current transformer to three-phase electric wire and zero line and carry out the measurement of electric current in step to show its waveform image synchronization, can conveniently be applied to the on-the-spot diagnosis of the electrified trouble of zero line.

Description

Electrified fault diagnosis device of low-voltage transformer area zero line

Technical Field

The utility model belongs to the technical field of electrical equipment detects, especially, relate to an electrified fault diagnosis device of low pressure platform district zero line.

Background

With the rapid development of the economy of China and a series of rural household appliance rural preferential policies of China, the rural electrical appliance level is continuously improved, but the frequency of zero line live faults in rural low-voltage transformer areas is also increased sharply, and the normal production and life of residents are seriously threatened by the occurrence of the zero line live faults. Because the low voltage distribution station area has more users, the outgoing line and the trend of the station area are complex, and the lighting and the electric appliances of residents at home are still working when the zero line fault occurs, the zero line live fault is difficult to be found by a power supply company in daily operation and maintenance.

For a long time, no effective detection method for live faults of the zero line of the overhead line in the low-voltage transformer area is available, and power failure removal methods such as a phase splitting method, a voltage method and a switching-off method are mostly adopted. When zero line faults occur in a low-voltage power supply area, firstly, whether residual current circuit breakers have faults is judged, if no faults exist, power is tested and transmitted to each branch line respectively to judge which branch has ground faults, after a fault branch is found out, all loads on the branch line are completely disconnected, power is tested and transmitted, if the power is tested and transmitted normally, a fault point is proved to be on a user side, and if the power is tested and transmitted abnormally, the fault point is proved to be on a low-voltage line. This type of treatment is labor and time consuming and also presents a significant safety hazard.

The live fault of the zero line can be detected by a method for measuring the insulation resistance, such as a megohmmeter connection measuring method, a comparison measuring method and the like. However, these methods require a reliable dc voltage-stabilized power supply and instruments and meters with high precision requirements, and are relatively troublesome to operate and difficult to implement. If the fault position is in the distribution line or the electric appliance behind the incoming line switch of the user or the equipment, the fault is easy to judge. However, if the fault point is in a distribution network formed by transformers, the grounding wires of the fault point are connected in parallel to form a common grounding mode, and the detection is difficult by using the method.

The clamp-on ammeter can solve the problems to a certain extent, and when the clamp-on ammeter is used for measuring the leakage fault, if a switch with the leakage fault cannot be closed, the leakage fault of the leakage switch or the leakage fault on a line needs to be detected firstly. If the leakage fault occurs on the line and the tripping is caused, the leakage switch is only required to be temporarily closed to stop the operation of the leakage switch. Firstly, removing an incoming neutral line of the leakage switch, then closing the switch with the leakage fault, adjusting the clamp-on ammeter to a milliampere gear to measure the phase line current, and then displaying the value on the ammeter as the value of the current with the leakage. The method is used for continuing on the lead with the leakage current until the tail end of the line is detected, and the position of the leakage fault can be found by analyzing the magnitude of the leakage current value. Compared with the traditional method, the method is safer, but the clamp-on ammeter can only give the value of the leakage current at the moment, and further analysis and positioning by workers are needed, so that the method is not beneficial to the workers to carry out troubleshooting in time. The clamp-on ammeter sold in the market at present has the advantages of small measurement range, low precision and low detection efficiency, and cannot judge whether faults exist in time, so that the requirement for electrified fault diagnosis of the overhead line zero line is difficult to meet.

Therefore, how to find and diagnose the live fault of the zero line of the overhead line in the low-voltage transformer area in time and improve the operation and management level of the overhead line is a difficult problem in line maintenance for many years.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an electrified fault diagnosis device of low pressure platform district zero line to the not enough of existence among the prior art. The diagnosis device can realize accurate analysis and diagnosis of live faults of the zero line.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a low-voltage transformer area zero line live fault diagnosis device comprises a sensor module, a signal preprocessing circuit, a data acquisition and processing module, a wireless transmission module and a man-machine interaction module; the sensor module, the signal preprocessing circuit and the data acquisition and processing module are sequentially connected; the data acquisition and processing module is in data transmission with the man-machine interaction module through the wireless transmission module.

The utility model discloses an introduce the current transformer to three-phase electric wire and zero line and carry out the measurement of electric current in step to show its waveform image synchronization, can conveniently be applied to the on-the-spot diagnosis of the electrified trouble of zero line.

The utility model can realize the sampling, display, storage and analysis of the zero line live fault current of the low-voltage transformer area; the sensor module can synchronously measure the current on the three phases and the zero line; extracting the waveform of the effective frequency band through the processing of a preprocessing circuit; and the data is uploaded to a human-computer interaction module of the upper computer for display through the wireless transmission module after being processed by the data acquisition and processing module, and is used for analysis and diagnosis of testers.

The utility model provides a sensor module, signal preprocessing circuit, data acquisition and processing module can be integrated as an organic whole, become an intelligent sensor, and this intelligent sensor and man-machine interaction module rethread wireless transmission module carry out data transmission, have avoided the loaded down with trivial details wiring of on-the-spot detection time measuring.

The utility model discloses further explain, sensor module contain four ways current transformer, cup joint respectively on A, B, C three-phase electric wire and zero line for response A, B, C three-phase current and zero line electric current. The utility model discloses a diagnostic device can read four ways current transformer's current value simultaneously, then to A, B, C three ways current transformer data ask the phasor with, compare with the zero sequence current value. Because the utility model is charged, the utility model discloses need to use insulating material, have sufficient dielectric strength.

The utility model discloses explain further, signal preprocessing circuit adopt active band pass filter. The filter has the advantages of few components, good stability and convenient parameter adjustment. The working principle is as follows:

transfer function:

from the virtual short break, the node voltage between R2 and C2 is 0, and the current is 0:

elimination of V_AThe transfer function is obtained:

then the amplitude of H (ω) is:

let the bandpass filter center frequency be f₀Then omega₀＝2πf₀At ω₀The value of | H (ω) | is maximized. From the mathematical function, it can be observed that | H (ω) | takes the maximum value when the preceding term of the denominator is 0. Then

The transfer function takes the maximum value:

center frequency:

gain:

in actual engineering practice to simplify calculations and design R1R 2,

center frequency f₀1/2 pi RC, gain A_v＝|H(ω)_max|＝C₁/2C₂。

The utility model discloses further explain, the data acquisition and processing module include AD chip, FPGA chip, ARM treater and FIFO memory; the FPGA chip is connected with the signal preprocessing circuit through the AD chip; the FIFO memory is connected with the FPGA chip; the ARM processor is connected with the FPGA chip through an AXI bus; the ARM processor is used for carrying out data transmission with the man-machine interaction module through the wireless transmission module.

The utility model discloses well FPGA can pass through AXI bus access ARM's memory to carry out the read-write operation. The FPGA controls the acquisition of front-end mutual inductor data by receiving a command issued by the ARM, and the detection data is firstly stored in the FIFO and then sent to the ARM through the AXI bus for data analysis and processing. The AXI bus is adopted to control transmission, the AXI protocol supports the design of a system supporting high performance and high frequency, the high-bandwidth low-delay design is suitable, high-frequency operation can be realized without a complex bridge, and the interface requirements of most devices are met.

The utility model discloses the electronic components who relates to in (for example AD chip, FPGA chip, ARM treater etc.) are the components and parts of conventional use, all can purchase in market and obtain according to required function, need not the specially limited model.

The utility model discloses further explain, wireless transmission module adopt the wireless transmission module based on Zigbee technique. The Zigbee technology provides data integrity check and authentication functions, adopts an AES-128 encryption algorithm, and has high safety, simple protocol and low cost. The sensor and the man-machine interaction module (detection host) are communicated in a wireless mode, and the field wiring complexity is reduced.

The utility model discloses explain further, human-computer interaction module adopt the liquid crystal touch-sensitive screen. The man-machine interaction module displays the test data through the liquid crystal screen and performs operation through the touch screen; the test data display device can be used for displaying the waveform of the test data and analyzing and assisting in positioning; the data can be stored and played back for long-term analysis and early warning of the line.

Compared with the prior art, the utility model discloses the beneficial effect who possesses:

1. the utility model discloses simple structure, use cost are low.

2. The utility model discloses can synchronous measurement three-phase and zero line electric current, the test data synchronism is good, and the waveform display is clear and definite, and easy contrastive analysis can conveniently be applied to the on-the-spot diagnosis of the electrified trouble of zero line.

3. The utility model discloses use wireless connection mode, the wiring is simple, and the security is high.

Drawings

Fig. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a detection principle of the sensor module in an embodiment of the present invention.

Fig. 3 is a schematic circuit diagram of a signal preprocessing circuit according to an embodiment of the present invention.

Fig. 4 is a system function structure diagram of the data collecting and processing module according to an embodiment of the present invention.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

Example (b):

as shown in fig. 1, the low-voltage transformer area zero line live fault diagnosis device comprises a sensor module, a signal preprocessing circuit, a data acquisition and processing module, a wireless transmission module and a human-computer interaction module; the sensor module, the signal preprocessing circuit and the data acquisition and processing module are sequentially connected; the data acquisition and processing module is in data transmission with the man-machine interaction module through the wireless transmission module.

Further, as shown in fig. 2, the sensor module includes four current transformers respectively sleeved on A, B, C three-phase wires and a zero line for inducing A, B, C three-phase current and zero line current.

Furthermore, the signal preprocessing circuit adopts an active band-pass filter. The circuit schematic diagram is shown in fig. 3, and mainly comprises resistors R1, R2, R3, capacitors C1, C2 and an operational amplifier U1.

Further, as shown in fig. 4, the data acquisition and processing module includes an AD chip, an FPGA chip, an ARM processor, and a FIFO memory; the FPGA chip is connected with the signal preprocessing circuit through the AD chip; the FIFO memory is connected with the FPGA chip; the ARM processor is connected with the FPGA chip through an AXI bus; the ARM processor is used for carrying out data transmission with the man-machine interaction module through the wireless transmission module.

The wireless transmission module described in this embodiment is a wireless transmission module based on the Zigbee technology. The man-machine interaction module adopts a liquid crystal touch screen.

It should be understood that the above-described embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the practice of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description; this is not necessary, nor exhaustive, of all embodiments; and obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims

1. The utility model provides a electrified fault diagnosis device of low pressure platform district zero line which characterized in that: the system comprises a sensor module, a signal preprocessing circuit, a data acquisition and processing module, a wireless transmission module and a human-computer interaction module;

the sensor module, the signal preprocessing circuit and the data acquisition and processing module are sequentially connected;

the data acquisition and processing module is in data transmission with the man-machine interaction module through the wireless transmission module.

2. The low-voltage transformer area neutral line live fault diagnosis device of claim 1, wherein: the sensor module comprises four current transformers which are respectively sleeved on A, B, C three-phase wires and a zero line and used for sensing A, B, C three-phase current and zero line current.

3. The low-voltage transformer area zero line live fault diagnosis device according to claim 1 or 2, characterized in that: the signal preprocessing circuit adopts an active band-pass filter.

4. The low-voltage transformer area neutral line live fault diagnosis device of claim 3, wherein: the data acquisition and processing module comprises an AD chip, an FPGA chip, an ARM processor and an FIFO memory; the FPGA chip is connected with the signal preprocessing circuit through the AD chip; the FIFO memory is connected with the FPGA chip; the ARM processor is connected with the FPGA chip through an AXI bus; the ARM processor is used for carrying out data transmission with the man-machine interaction module through the wireless transmission module.

5. The low-voltage transformer area neutral line live fault diagnosis device of claim 1, wherein: the wireless transmission module adopts a Zigbee technology-based wireless transmission module.

6. The low-voltage transformer area neutral line live fault diagnosis device of claim 1, wherein: the man-machine interaction module adopts a liquid crystal touch screen.

7. The low-voltage transformer area neutral line live fault diagnosis device of claim 1, wherein: the sensor module, the signal preprocessing circuit and the data acquisition and processing module are integrated into a whole.