Small current grounding system single phase earth fault traveling wave line selection and distance measurement apparatus

A single-phase ground fault, small current grounding technology, applied in the field of power system, can solve the problems of being easily affected by interference signals, etc., and achieve the effect of wide application range and accurate measurement of fault distance

Inactive Publication Date: 2011-10-19

SHENZHEN SUOTU TECH

5 Cites 36 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0009] The invention provides a single-phase ground fault traveling wave line selection and distance measuring device for a small current grounding system. Aiming at the current problem of small current ground fault line selection, the hardware technology of high-speed acquisition, high-resolution sampling and high-precision synchronization is adopted, combined with The original fault start discrimination algorithm e...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Method used

The high-speed acquisition board has the detection and judgment function of line fault, and when line is running normally, system collects analog quantity, calculates whether zero-sequence voltage exceeds recording start set value, when ground fault occurs in line, on the bus The zero-sequence voltage exceeds the limit to start, and then the DSP digital signal processor of the high-speed acquisition board automatically calculates and compares the size and direction of the traveling wave head, and output...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Abstract

The invention provides a small current grounding system single phase earth fault traveling wave line selection and distance measurement apparatus which comprises a signal conversion plate, a high speed acquisition plate and a central management machine. The signal conversion plate converts bus zero sequence voltage and line current to 0 to 10 volts voltage signal after isolation. The high speed acquisition plate connecting with the signal conversion plate finishes the conversion from analog signal to digital signal, carries out high speed acquisition and caching, receives a synchronization time setting signal simultaneously, and marks data with absolute marker. A digital signal processor (DSP) of the high speed acquisition plate calculates whether the zero sequence voltage exceeds a starting set value or not, wherein, if so, line fault happens. The DSP automatically searches and calculates a tip size and direction of traveling wave, and outputs line selection result through a switch output plate connecting the high speed acquisition plate. Simultaneously wave recording is started to record fault data which is transmitted to the central management machine through a high speed bus. According to the wave recording data, the central management machine automatically searches initial wave tip of the fault line and time of fault point reflection wave tip, and calculates distance of the fault point. Finally, fault data and fault report are published through a WEB SERVER platform.

Application Domain

Fault location

Technology Topic

Single phaseWeb server +13

Image

Examples

Experimental program(1)

Example Embodiment

[0038] The present invention will be further described below in conjunction with specific embodiments and with reference to the drawings.

[0039] The working principle diagram of the present invention, such as figure 1 Shown. The signal conversion board converts the zero sequence voltage and line current of the bus bar, including phase current, zero sequence current, etc., into a 0-10 volt voltage signal through isolation, and transmits it to the high-speed acquisition board connected to the signal conversion board.

[0040] The high-speed acquisition board, after receiving the 0-10V voltage signal from the signal conversion board, completes the conversion of analog signals into digital signals, and then performs high-speed acquisition and buffering. The high-speed acquisition board simultaneously receives the seconds pulse or B code granted by GPS and Beidou satellites as the synchronous sampling signal of each device, and the data is marked with an absolute time stamp. Then the DSP digital signal processor of the high-speed acquisition board calculates whether the zero-sequence voltage exceeds the record start setting value. Exceeding the setting value indicates that the line is faulty. DSP will automatically find and calculate the size and direction of the initial traveling wave wave head. The switch output board of the board outputs the line selection result. Start recording at the same time. After the high-speed acquisition board starts the recording, it will record and collect the fault data of two cycles before and after the fault. Then the data is transmitted to the central management machine connected to the high-speed acquisition board through the high-speed bus.

[0041] The central management computer receives the fault data sent by the high-speed acquisition board, calculates the amplitude of the fault line current traveling wave through wavelet transform, finds the initial traveling wave and the wave head time reflected by the fault point, and calculates the distance to the fault point. The error is within 300 meters. Finally, the fault data and fault report are released through the built-in WEB SERVER platform, and the user can realize network communication functions such as fault report and fault data review through the IE browser.

[0042] The working principle diagram of the acquisition board of the present invention, such as figure 2 Shown. The high-speed data acquisition board completes the high-speed acquisition and buffering of the traveling wave signal, receives the 0-10 volt voltage signal transmitted by the signal conversion board, performs A/D sampling, and completes the conversion of analog signals into digital signals. Under normal operation conditions, the frequency is 1MHz-5MHz The frequency is written into SDRAM under the control of FPGA. SDRAM is divided into several storage areas in units of 80 milliseconds. With the block as the control unit, it receives GPS and Beidou satellites at the same time to obtain time reference, and uses GPS, Beidou satellites, etc. The granted time such as the second pulse or B code is used as the synchronous sampling time scale of the device. The data is marked with absolute time stamp when writing, and the time signal error is 1×10 -8 second. This time scale realizes the time uniformity of the data of other devices in the system.

[0043] The sampled data is stored in a data area in a cyclic storage mode. When the external line selection start signal is received, the data storage area stops refreshing, and the sampled data after the start is stored in another data area. Refresh is allowed, but the refresh signal can be controlled externally. The length of the line selection data recording buffer is 80 milliseconds. In order to ensure that the failure data will not be lost when the power grid has a continuity failure, multiple data buffers have been opened on the high-speed acquisition DSP board. When a failure occurs during the transfer of the current recording data, the current failure data can still be recorded. When a piece of data is transmitted to the central management machine, the central management machine gives a refresh signal and the corresponding line selection data block serial number. After the high-speed acquisition DSP board receives the refresh signal, the corresponding data block can be refreshed.

[0044] The high-speed acquisition board has a line fault detection and judgment function. When the line is running normally, the system collects analog data and calculates whether the zero-sequence voltage exceeds the record start setting value. When the line has a ground fault, the zero-sequence voltage on the bus When the amount exceeds the limit, the DSP digital signal processor of the high-speed acquisition board automatically calculates and compares the size and direction of the traveling wave wave head, and outputs the line selection result through the switch output board connected to the high-speed acquisition board. At the same time, the recording is started, and the fault data of two cycles before and after the fault is stored for 80 milliseconds. And adopt the floating threshold starting method to improve the sensitivity and reliability of fault detection and judgment. Then the data is transmitted to the central management machine connected to the high-speed acquisition board through the high-speed bus.

[0045] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, if several equivalent substitutions or obvious modifications are made without departing from the concept of the present invention, and the performance or use is the same, they should be regarded as belonging to the claims submitted by the present invention. The scope of protection determined by the book.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more

PUM

Description & Claims & Application Information

We can also present the details of the Description, Claims and Application information to help users get a comprehensive understanding of the technical details of the patent, such as background art, summary of invention, brief description of drawings, description of embodiments, and other original content. On the other hand, users can also determine the specific scope of protection of the technology through the list of claims; as well as understand the changes in the life cycle of the technology with the presentation of the patent timeline. Login to view more.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more

Classification and recommendation of technical efficacy words

Wide range of applications

Small current grounding system single phase earth fault traveling wave line selection and distance measurement apparatus

A single-phase ground fault, small current grounding technology, applied in the field of power system, can solve the problems of being easily affected by interference signals, etc., and achieve the effect of wide application range and accurate measurement of fault distance

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Image

Examples

Example Embodiment

PUM

Description & Claims & Application Information

Similar technology patents

Test platform for wind driven generator

Deep building pit trussed-beam inner support integral application pre-stress method

Nano talcpowder modified polypropylene composite material and preparation method thereof

Process for removing bitter taste of momordica grosvenori extract

Compound microbe fermentation strain preparing method and its use

Classification and recommendation of technical efficacy words

Automatic guide and obstacle avoidance method for robot

Method for preparing nitrogen-doped graphene material with hydrothermal process

Novel composite ecological cement and product application thereof

Tolerogenic biodegradable artificial antigen presenting system

Multiple point touch localization method