CN201576056U - Grounding resistance online detector based on TMS320LF2407A - Google Patents
Grounding resistance online detector based on TMS320LF2407A Download PDFInfo
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- CN201576056U CN201576056U CN2009202265355U CN200920226535U CN201576056U CN 201576056 U CN201576056 U CN 201576056U CN 2009202265355 U CN2009202265355 U CN 2009202265355U CN 200920226535 U CN200920226535 U CN 200920226535U CN 201576056 U CN201576056 U CN 201576056U
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Abstract
The utility model discloses a grounding resistance online detector based on TMS320LF2407A, comprising a current nip, a preamplifier module, a program control active filter, a voltage nip, a power amplifier module, a low-frequency frequency-conversion signal generator, a partial pressure module, a coupling voltage sampling module and a TMS320LF2407A digital signal processor, wherein the current nip, the preamplifier module and the program control active filter are connected in sequence and then are accessed to one input port of the TMS320LF2407A digital signal processor; the voltage nip, the power amplifier module and the low-frequency frequency-conversion signal generator are connected in sequence and then are accessed to one output port of the TMS320LF2407A digital signal processor; the voltage nip, the partial pressure module and the coupling voltage sampling module are connected in sequence and then are accessed to another input port of the TMS320LF2407A digital signal processor. The grounding resistance online detector based on TMS320LF2407A has the advantages that by the TMS320LF2407A digital signal processor, the grounding resistance online detector can precisely process the collected data, so the measurement precision is high, and the errors are small; and the grounding resistance online detector has simple structure and low cost.
Description
Technical field
The utility model relates to a kind of stake resistance on-line detector, particularly a kind of stake resistance on-line detector based on TMS320LF2407A.
Background technology
Generating plant, substation grounding system are the important measures of safeguarding the power system security reliability service, ensureing electrical equipment and operations staff's safety.In order to prevent that effectively power equipment from being damaged because of being struck by lightning, DL/T 621-1997 " ground connection of alternating-current electric device " has proposed very strict requirement to the line service of substation grounding and lightning protection facility, as every year before thunderstorm season arrives to all lightning protection facilities once check comprehensively, the stake resistance that should be not more than 1 Ω, 110kV and above generating plant, grounding net of transformer substation for complicated electrical equipment integrated ground resistance should be not more than 0.5 Ω, large-scale 220～500kV generating plant, transformer station should be not more than 0.25 Ω etc.
Reasonably selecting measurement instrument is that the prerequisite that stake resistance is accurately measured is guaranteed.With regard to present stake resistance on-line detector, can mainly contain two types for what the user selected: first kind is traditional megger formula numeral instrument for measuring earth resistance, and second kind is the single jaw ground resistance measuring instrument.
One, traditional megger formula numeral instrument for measuring earth resistance
Its measuring principle is to inject low-frequency ac electric current I between the electric current utmost point and tested grounding body, can obtain a voltage U this moment between tested grounding body and voltage pole, by measuring this electric current and magnitude of voltage,, can calculate the stake resistance of tested grounding body according to Ohm law R=U/I.But it has following shortcoming: (1) each measurement all will be made a call to two auxiliary earth polars, this has not only increased the labour intensity of safeguarding, and many field conditions can't satisfy on the earth mat diagonal electric current interpole apart from earth mat about 40 meters can't beat auxiliary earth polar or beat auxiliary earth polar the time, and the voltage interpole is apart from 20 meters these requirements of earth mat; (2) measuring accuracy is very low, particularly the measurement to hindering below 0.5 Ω; (3) because whole measuring process all is manually-operated from beating auxiliary pile to measuring, thus measurement result influenced by human factor very big, handle shakes that speed is slow excessively, frequency is inhomogeneous etc. and all can measurement result be produced a very large impact during as measurement; Need when (4) measuring grounding body is disconnected with equipment,, thereby can not realize on-line measurement with the accuracy of avoiding the influence of equipment self grounding body to measure.
Two, single jaw ground resistance measuring instrument
Hinder off-balancesheet shape pincerlikely and exactly like clamp on amperemeter, need not assist the earth polar during measurement, can carry out on-line measurement to hindering on ground with equipment, and need not cut off device power supply (DPS) or disconnect ground wire, only need toward one being pressed from both sides on the geodesic line, can obtain measurement result several seconds, be very easy to grounding resistance measurement work, but it has following shortcoming: (1) is because instrument has single-frequency to the low-frequency ac voltage that ground loop injects, when its frequency and electrical equipment earth mat leakage current frequency near the time, measuring accuracy is very low, when serious even can't measure; (2) because voltage injects coil and current measurement coil combination in same jaw, so the mutual inductance effect between coil and the coil has considerable influence to measuring accuracy; (3) measuring 0.7 Ω, to hinder error bigger followingly, can not satisfy the measurement that 0.5 Ω hinders followingly; (4) the jaw internal diameter is little, is generally 25mm,, can't measure greater than the earth mat of 25mm the earth mat wire widths.
Summary of the invention
Problem to be solved in the utility model is: provide a kind of can be accurately to stake resistance measure, cheap stake resistance on-line detector based on TMS320LF2407A.
In order to solve the problems of the technologies described above, stake resistance on-line detector based on TMS320LF2407A of the present utility model comprises electric current jaw, pre-amplifying module, program control active filter, voltage jaw, power amplifier module, low frequency frequency variation signal generator, division module, coupled voltages sampling module and TMS320LF2407A digital signal processor; Described electric current jaw, pre-amplifying module and be linked into an input port of TMS320LF2407A digital signal processor after program control active filter links to each other successively; Described voltage jaw, power amplifier module and be linked into a delivery outlet of TMS320LF2407A digital signal processor after low frequency frequency variation signal generator links to each other successively; Described voltage jaw, division module and be linked into the another one input port of TMS320LF2407A digital signal processor after the coupled voltages sampling module is connected successively.
Stake resistance on-line detector based on TMS320LF2407A of the present utility model also is connected with LCD display, keyboard input module and RS232 communication interface respectively on the described TMS320LF2407A digital signal processor.
The beneficial effect that the utility model is obtained is: (1) can handle the data that collected by the TMS320LF2407A digital signal processor accurately, so the measuring accuracy height, and error is little; (2) simple in structure, price is comparatively cheap, and the very high ratio of performance to price is arranged.
Description of drawings
Fig. 1 is a framed structure synoptic diagram of the present utility model.
Among the figure: 1, electric current jaw, 2 pre-amplifying modules, 3, division module, 4, program control active filter, 5, coupled voltages sampling module, 6, TMS320LF2407A digital signal processor, 7, LCD display, 8, keyboard input module, 9, voltage jaw, 10, power amplifier module, 11, low frequency frequency variation signal generator, 12, the RS232 communication interface.
Embodiment
As shown in Figure 1, stake resistance on-line detector based on TMS320LF2407A of the present utility model comprises electric current jaw 1, pre-amplifying module 2, program control active filter 4, voltage jaw 9, power amplifier module 10, low frequency frequency variation signal generator 11, division module 3, coupled voltages sampling module 5 and TMS320LF2407A digital signal processor 6; Described electric current jaw 1, pre-amplifying module 2 and be linked into an input port of TMS320LF2407A digital signal processor 6 after program control active filter 4 links to each other successively; Described voltage jaw 9, power amplifier module 10 and be linked into a delivery outlet of TMS320LF2407A digital signal processor 6 after low frequency frequency variation signal generator 11 links to each other successively; Described voltage jaw 9, division module 4 and be linked into the another one input port of TMS320LF2407A digital signal processor 6 after coupled voltages sampling module 5 is connected successively; Also be connected with LCD display 7, keyboard input module 8 and RS232 communication interface 12 on the described TMS320LF2407A digital signal processor 6 respectively.
Explanation about TMS320LF2407A digital signal processor 6:
TMS320LF2407A digital signal processor 6 has adopted the TMS320LF2407A of TI company production as detecting core.In this measuring instrument, adopt programmable gain amplifier (PGA) realization range switching in the sheet; Adopt coupled voltages and the induction current of electric current jaw and the interference current in the earth loop of ADC subsystem measuring voltage jaw in the sheet; Adopt the frequency of task manager module EV measurement interference current in the sheet; Adopt temperature sensor realization temperature detection in the sheet; Utilize voltage comparator realization battery undervoltage alarm in the sheet; Utilize the interior serial port of sheet that measurement data is uploaded to host computer.This shows, adopt TMS320LF2407A digital signal processor 6 single chips can finish the measurement of stake resistance, simplified The Hardware Design, reduced system cost and power consumption, prolonged the serviceable life of supplying cell.
Explanation about pre-amplification circuit 2:
Because the induction current variation range in the earth loop is bigger, be generally tens μ A～tens mA, faradic amplitude minimum in the electric current jaw only is tens μ A like this, therefore differential amplifier adopts high-accuracy instrumentation amplifier AD620 in this measuring instrument, its internal core is three discharge circuits, and higher common-mode rejection ratio CMRR is arranged, and temperature stability is good, noise figure is little, as long as an external resistance just can be provided with 1～3000 gain.
Because the dynamic range that this measuring instrument is measured is bigger, be to improve measuring accuracy, adopted the programmable gain amplifier in the TMS320LF2407A sheet, by the register setting adjustment that can gain.
Explanation about program control active filter 4:
The AC ripple and the output noise of electrical equipment owing to superposeed usually on the induction current in the earth loop, the amplitude of these undesired signals and the induced signal in the earth loop may be quite, sometimes even bigger, therefore must carry out good filtering to the measuring-signal in the earth loop, to weaken undesired signal.Select two second order universal switch capacitor filter MAX260 for use at this, follow TMS320LF2407A digital signal processor 6 interfaces by parallel bus, can be set to easily that band is logical, working methods such as low pass, high pass, trap and all-pass, its centre frequency, corner frequency, Q value all can be controlled by TMS320LF2407A digital signal processor 6.
In this measuring instrument according to the difference of interference current frequency, the frequency of the low-frequency ac voltage that potential winding produces can be selected in 94Hz, 105Hz, four kinds of frequencies of 111Hz, 128Hz automatically, so the centre frequency of active filter MAX260 also must make corresponding changes.When the induction current of the coupled voltages of measuring voltage jaw and electric current jaw, this wave filter is operated in the bandpass filtering mode; When measuring interference current, be operated in the low-pass filtering mode.These are all by 6 controls of TMS320LF2407A digital signal processor.
Explanation about low frequency frequency variation signal generator 11:
Low frequency frequency variation signal generator 11 common implementation methods have two kinds: analog and digital.Analog characteristics are that circuit is fairly simple, but when output frequency is very low, need very big electrochemical capacitor, can produce bigger frequency drift, and change the parameter value that output frequency need change elements such as resistance, electric capacity, adjust cumbersome; And digital circuit is relatively complicated, but the frequency signal that produces is very accurate, and it is simpler to change frequency.For this reason, the utility model has adopted digital signal generator ML2036.
ML2036 is the integrated zero passage sine-wave generator of output frequency monolithic able to programme that Fairchild company (Fairchild Semiconductor) releases, and need not outer member.By the optional frequency between serial SPI digital interface programming output DC～50kHz, full scale resolution 1.5Hz, can improve resolution by reducing reference frequency output, can provide ± VREF or ± the voltage output amplitude of VREF/2, be that the low-cost sinusoidal wave ideal of using of low frequency is selected.
Calculate about stake resistance:
According to the alternating voltage and the faradic numerical value of detector injection earth loop of the present utility model, can calculate the numerical value of stake resistance.
Claims (2)
1. the stake resistance on-line detector based on TMS320LF2407A is characterized in that: comprise electric current jaw (1), pre-amplifying module (2), program control active filter (4), voltage jaw (9), power amplifier module (10), low frequency frequency variation signal generator (11), division module (3), coupled voltages sampling module (5) and TMS320LF2407A digital signal processor (6); Described electric current jaw (1), pre-amplifying module (2) and be linked into an input port of TMS320LF2407A digital signal processor (6) after program control active filter (4) links to each other successively; Described voltage jaw (9), power amplifier module (10) and be linked into a delivery outlet of TMS320LF2407A digital signal processor (6) after low frequency frequency variation signal generator (11) links to each other successively; Described voltage jaw (9), division module (4) and be linked into the another one input port of TMS320LF2407A digital signal processor (6) after coupled voltages sampling module (5) is connected successively.
2. the stake resistance on-line detector based on TMS320LF2407A according to claim 1 is characterized in that: also be connected with LCD display (7), keyboard input module (8) and RS232 communication interface (12) on the described TMS320LF2407A digital signal processor (6) respectively.
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| CN2009202265355U CN201576056U (en) | 2009-09-18 | 2009-09-18 | Grounding resistance online detector based on TMS320LF2407A |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102749519A (en) * | 2012-04-18 | 2012-10-24 | 云南电网公司昆明供电局 | On-line resistor intelligent-monitoring system and lower computer |
| CN103018571A (en) * | 2012-12-05 | 2013-04-03 | 北京工业大学 | Dual-coupling type on-line monitoring device of ground impedance of electric transmission line |
| CN104330633A (en) * | 2014-10-22 | 2015-02-04 | 中国石油化工股份有限公司 | Floating roof storage tank float tray connection wire on-line monitoring device |
| CN104749444A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Grounding resistance measuring device |
| CN104749443A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Measuring device for grounding resistance |
| CN105738703A (en) * | 2016-03-31 | 2016-07-06 | 南京信息工程大学 | On-line measurement device and measurement method of grounding resistor |
| CN105891605A (en) * | 2014-11-04 | 2016-08-24 | 国电龙源电气有限公司 | Distribution transformer grounding resistor, current online measurement equipment and method thereof |
| CN109470929A (en) * | 2018-10-18 | 2019-03-15 | 天津天禹水务工程勘察设计有限公司 | Real-time earthing lightning protection monitoring system and monitoring method based on Internet of Things |
| CN112666398A (en) * | 2020-12-30 | 2021-04-16 | 苏州工业园区科佳自动化有限公司 | Intelligent grounding resistance monitor of lightning protection equipment |
| CN117590084A (en) * | 2023-11-14 | 2024-02-23 | 国网江苏省电力有限公司南通市海门区供电分公司 | Device and method for measuring grounding resistance of transmission line tower |
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2009
- 2009-09-18 CN CN2009202265355U patent/CN201576056U/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102749519A (en) * | 2012-04-18 | 2012-10-24 | 云南电网公司昆明供电局 | On-line resistor intelligent-monitoring system and lower computer |
| CN103018571A (en) * | 2012-12-05 | 2013-04-03 | 北京工业大学 | Dual-coupling type on-line monitoring device of ground impedance of electric transmission line |
| CN104749444A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Grounding resistance measuring device |
| CN104749443A (en) * | 2013-12-31 | 2015-07-01 | 孙巍巍 | Measuring device for grounding resistance |
| CN104330633A (en) * | 2014-10-22 | 2015-02-04 | 中国石油化工股份有限公司 | Floating roof storage tank float tray connection wire on-line monitoring device |
| CN105891605A (en) * | 2014-11-04 | 2016-08-24 | 国电龙源电气有限公司 | Distribution transformer grounding resistor, current online measurement equipment and method thereof |
| CN105738703A (en) * | 2016-03-31 | 2016-07-06 | 南京信息工程大学 | On-line measurement device and measurement method of grounding resistor |
| CN105738703B (en) * | 2016-03-31 | 2018-09-04 | 南京信息工程大学 | A kind of the on-line measurement device and measurement method of ground resistance |
| CN109470929A (en) * | 2018-10-18 | 2019-03-15 | 天津天禹水务工程勘察设计有限公司 | Real-time earthing lightning protection monitoring system and monitoring method based on Internet of Things |
| CN112666398A (en) * | 2020-12-30 | 2021-04-16 | 苏州工业园区科佳自动化有限公司 | Intelligent grounding resistance monitor of lightning protection equipment |
| CN117590084A (en) * | 2023-11-14 | 2024-02-23 | 国网江苏省电力有限公司南通市海门区供电分公司 | Device and method for measuring grounding resistance of transmission line tower |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
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Owner name: STATE ELECTRIC NET CROP. Effective date: 20130709 |
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| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20130709 Address after: 261000 Weicheng, Shandong, Dongfeng District, No. West Street, No. 425 Patentee after: Shandong Electric Power Corporation Weifang Power Supply Co., Ltd. Patentee after: State Grid Corporation of China Address before: 261000 Weicheng, Shandong, Dongfeng District, No. West Street, No. 425 Patentee before: Shandong Electric Power Corporation Weifang Power Supply Co., Ltd. |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100908 Termination date: 20170918 |
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| CF01 | Termination of patent right due to non-payment of annual fee |