CN201434893Y - Multi-point synchronous measurement type digital grounding resistance tester - Google Patents

Multi-point synchronous measurement type digital grounding resistance tester Download PDF

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Publication number
CN201434893Y
CN201434893Y CN2009200648945U CN200920064894U CN201434893Y CN 201434893 Y CN201434893 Y CN 201434893Y CN 2009200648945 U CN2009200648945 U CN 2009200648945U CN 200920064894 U CN200920064894 U CN 200920064894U CN 201434893 Y CN201434893 Y CN 201434893Y
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signal
output terminal
electronic switch
resistance
power supply
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CN2009200648945U
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罗望保
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Abstract

The utility model discloses a multi-point synchronous measurement type digital grounding resistance tester, which comprises a switching power supply, a resistance measurement reference power supply, apulse signal generator, a power inverter, an electronic switch, a filter unit, an earth resistance demodulation and A / D converter, an earth resistance signal amplifier, a control unit and the likeconnected in sequence. The electronic switch can be switched on and off between a plurality of tested electrodes and can sample the voltage between the tested electrode and the potential electrode, thereby realizing the automatic testing of a group of earth wires in one machine room. With the base frequency signal of 550Hz, and the RC filter circuit, the phase locked loop circuit and the digital filtering device for filtering, the utility model has good effect on the inhibition of the signals with strong interference such as the power frequency, instantaneous pulse, ground clutter and the like, thereby greatly improving the accuracy of the test data and also the anti-jamming rate.

Description

Multi-point simultaneous-measurement digital grounding resistance tester
Technical field
The utility model relates to a kind of earth resistance tester, particularly a kind of multi-point simultaneous-measurement digital grounding resistance tester.
Background technology
The digital grounding resistance tester kind is more both at home and abroad at present, but the function unanimity.Three outstanding problems of ubiquity in actual applications: the one, when meeting the ground interference of electromagnetic field, poor anti jamming capability, test reading instability, and data deviation is very big; The 2nd, the no datat transmission interface is not easy to realize microcomputer monitoring and remote monitoring; The 3rd, when having the different purposes ground wires of many groups to test respectively in the electrical equipment machine room (such as safety line, working grounding cable, lightning protection ground wire, logic ground wire etc. are arranged), existing earth resistance tester can only go the wiring test singly respectively, both bothered like this, work efficiency is also low, more can't satisfy current detection automatically, the requirement of remote monitoring.
The utility model content
Technical problem to be solved in the utility model is: at the deficiency of existing earth resistance tester technology, provide that a kind of anti-ground interference of electromagnetic field ability is strong, test reading is reliable and stable, can organize the multi-point simultaneous-measurement digital grounding resistance tester that different purposes ground wires are tested respectively automatically more in the electrical equipment machine room.
For solving the problems of the technologies described above, the technical scheme that the utility model adopted is: a kind of multi-point simultaneous-measurement digital grounding resistance tester, and it comprises:
One Switching Power Supply, this Switching Power Supply comprise first output terminal and second output terminal, and this Switching Power Supply is used for civil power 220V alternating current is converted into the required low-voltage DC of tester;
One resistance measurement reference power supply, its input end is connected with second output terminal of Switching Power Supply, and its output terminal is connected with the reference signal input end of ground resistance signal amplifier, thereby provides a reference signal for ground hinders signal amplifier;
One pulse signal generator, it has a plurality of pulse signal output ends, the full sized pules signal that those output terminal output frequencies are 550Hz;
One power inverter, its input end is connected with first output terminal of Switching Power Supply, its trigger end is connected with a pulse signal output end of pulse signal generator, it is under the full sized pules signal triggering of 550Hz in the frequency that pulse signal generator sends, the direct current of Switching Power Supply first output terminal output is modulated the envelope AC signal that changes frequency 550Hz and current constant into, to provide test required constant current source;
One electronic switch, the tested electrode of its external a plurality of usual disconnections and a potential electrode and a testing current electrode, the input end of this electronic switch connects the output terminal of power inverter, this electronic switch also comprises the voltage sample unit that can sample to voltage between tested electrode and the potential electrode, the sampled signal of this voltage sample unit output is through the sampled voltage output terminal output of electronic switch, during test, under control module control, electronic switch switches between a plurality of tested electrodes, respectively different tested electrodes are connected, make and hinder test point a plurality ofly and alternately insert in the loop, realize the ground resistance of a plurality of different ground wires is tested;
One filter unit, it comprises RC filtering circuit and phase-locked loop circuit, the input end of this filter unit is connected with the sampled voltage output terminal of electronic switch;
Resistance signal demodulation of one ground and A/D converter, its input end connects the output terminal of filter unit, and the demodulation of filtered analog quantity sampled voltage signal is converted into pulsation shape digital sample voltage signal;
One ground resistance signal amplifier, its input end connects the output terminal of demodulation and A/D converter, and the shape digital sample voltage signal of will pulsing amplifies earlier, proofreaies and correct and checks and approves, and is transported to control module then;
One control module, its input end connects the output terminal of ground resistance signal amplifier, its output terminal is connected with electronic switch and display device, this control module output instruction signal is given electronic switch, electronic switch is switched between different tested electrodes, this control module also comprises digital filter apparatus and can be according to the APU of sampled voltage calculated signals ground resistance, earlier carry out digital filtering from the digital sample voltage signal of ground resistance signal amplifier Input Control Element through digital filter apparatus, treating apparatus hinders with calculating by analysis again, and to this ground resistance is stored, and send display device to and show.
Also be provided with the data communication mouth on the described control module.
Described control module is robot calculator or single-chip microcomputer.
Compared with prior art, the beneficial effects of the utility model are: electronic switch of the present utility model can switch between a plurality of tested electrodes under the control of control module, make and hinder test point a plurality ofly and alternately insert in the test loop, thereby can realize the ground resistance of a plurality of different ground wires is tested automatically; In addition, the utility model has adopted comprehensive anti-jamming circuit pattern, and it is mainly: the one, and the signal frequency that pulse signal generator is selected for use is 550HZ, departs from fundamental frequency and two, the third harmonic of strong interferers power frequency far away, is weakened strong power frequency and disturbs; The 2nd, adopted phaselocked loop to follow the tracks of the detection technology synchronously, make the test signal sent and the feedback signal of reception not produce frequency deviation, other interfering frequency signals can't be scurried into, weakened the interference of other ground vapour clutter; The 3rd, adopt digital filter apparatus, promptly in a period, detected signal amplitude is carried out analyzing and processing, average again after high-amplitude disturbing pulse that moment is occurred or low amplitude signal are got rid of, can cut down the interference of outside momentary pulse signal so greatly.Owing to adopted above-mentioned comprehensive anti-jamming circuit pattern, the utility model has the good restraining effect for high reject signals such as power frequency, momentary pulse, ground vapour clutters, thereby makes the test data accuracy rate improve greatly.Relatively confirm through test, test stake resistance with stem-winder being disturbed big place, its grounding resistance is 0.6 ohm, and grounding resistance changes between 0.2-3.6 ohm during with on the market digital grounding resistance test chart (containing the domestic and imported table) test at present, when using the utility model multi-point simultaneous-measurement digital grounding resistance tester, grounding resistance then changes between 0.55-0.65 ohm, illustrate that the utility model interference free performance is better than existing digital grounding resistance test chart, its noise immunity can reach more than 90%.
Description of drawings
Fig. 1 is the block scheme of the utility model one embodiment.
Embodiment
As shown in Figure 1, the utility model one embodiment comprises:
One Switching Power Supply 1, this Switching Power Supply 1 comprise output voltage be ± first output terminal of 15V and output voltage be second output terminal of ± 6V, this Switching Power Supply 1 is used for civil power 220V alternating current is converted into ± 15V and ± low-voltage DC of 6V;
One resistance measurement reference power supply 2, its input end is connected with second output terminal of Switching Power Supply 1, its output terminal is connected with the reference signal input end of ground resistance signal amplifier 3, and it mainly is the reference power supply that produces one ± 3V, reference signal is provided for ground resistance signal amplifier 3.
One pulse signal generator 5, it has a plurality of pulse signal output ends, the full sized pules signal that those output terminal output frequencies are 550Hz;
One power inverter 4, its input end is connected with first output terminal of Switching Power Supply 1, its trigger end is connected with a pulse signal output end of pulse signal generator 5, it can be under the full sized pules signal triggering of 550Hz in the frequency that pulse signal generator sends, with the output of first output terminal of Switching Power Supply 1 ± the envelope AC signal of the modulation changing into of 15V direct current frequency 550Hz and current constant (in the present embodiment, this signal is a 29V/25mmA/550HZ envelope AC signal), to provide test required constant current source;
One electronic switch 6, tested electrode E and a potential electrode P and a testing current electrode C that can external a plurality of usual disconnections.The input end of this electronic switch 6 connects the output terminal of power inverter 4.This electronic switch 6 also comprises the voltage sample unit that can sample to voltage between tested electrode E and the potential electrode P, and the sampled signal of this voltage sample unit output is through the sampled voltage output terminal output of electronic switch 6.During test, under control module 10 controls, electronic switch 6 can switch between a plurality of tested electrode E, respectively different tested electrode E is connected, thereby make and hinder test point a plurality ofly and alternately insert in the loop, realize the ground resistance of a plurality of different ground wires is tested.
One filter unit 7, it comprises RC filtering circuit and phase-locked loop circuit, the input end of this filter unit 7 is connected with the sampled voltage output terminal of electronic switch 6.What RC filtering circuit herein and phase-locked loop circuit adopted all is custom circuit.Behind the RC filtering circuit, set up phase-locked loop circuit again, will carry out from motion tracking and be locked in 550Hz, further reduce of the interference of other power frequency, thereby improve measuring accuracy test signal through the testing source behind the RC filtering circuit.
Resistance signal demodulation of one ground and A/D converter 8, its input end connects the output terminal of filter unit 7, and the demodulation of filtered analog quantity sampled voltage signal is converted into pulsation shape digital sample voltage signal.
One ground resistance signal amplifier 3, its input end connects the output terminal of ground resistance signal demodulation and A/D converter 8, the pulsation shape digital sample voltage signal of input is amplified earlier, proofread and correct with the standard of 0.10 Ω/10mV again and check and approve, be transported to control module 10 identifications then and handle.
One control module 10, its input end connects the output terminal of ground resistance signal amplifier 3, its output terminal is connected with electronic switch 6 and display device 11, and these control module 10 output instruction signals are given electronic switch 6, and electronic switch 6 is switched between different tested electrode E.This control module 10 also comprises a digital filter apparatus 12 and can be according to the APU 13 of the sampled voltage calculated signals stake resistance of input.Earlier carry out digital filtering from the ground resistance signal of ground resistance signal amplifier 3 Input Control Elements 10 through digital filter apparatus 12, promptly in a period, detected signal amplitude is carried out analyzing and processing, after being got rid of, high-amplitude disturbing pulse that moment is occurred or low amplitude signal average again, can cut down the interference of outside momentary pulse signal so greatly, further improve measuring accuracy; Treating apparatus 13 calculates stake resistance by analysis again, this stake resistance calculating method is: the current value of first storage power inverter 4 outputs, again will be through the current value of digital filter apparatus 12 filtered sample voltage value divided by power inverter output, get final product grounding resistance.This control module 10 is robot calculator or single-chip microcomputer.
One display device 11, this display device 11 is connected with control module 10, is used for the grounding resistance that indicative control unit 10 sends and the Measuring Time of corresponding grounding resistance.
When the utility model is worked, at first control module 10 sends instruction and makes electronic switch 6 connections one tested electrode E, simultaneously Switching Power Supply 1 the 220V alternating current that the outside provides is converted into ± 15V and ± low-voltage DC of 6V, to provide the utility model required dc supply.Resistance measurement reference power supply 2 connect Switching Power Supplies 1 the output of second output terminal ± low-voltage DC of 6V direct current and being translated into ± 3V and hinder signal amplifier 3 with offering and do reference signal.First output terminal output of the input end connection Switching Power Supply 1 of power inverter 4 ± the 15V low-voltage DC, and under the 550HZ full sized pules signal triggering that pulse signal generator 5 sends, the dc inverter of general ± 15V is the AC constant-current source of 29V/25mmA/550HZ, deliver to the tested electrode E of tested earth mat through electronic switch 6, potential electrode P, between the testing current electrode C, sample to voltage between tested electrode E and the potential electrode P in voltage sample unit in the electronic switch 6, and with the sampled voltage output terminal output of this sampled signal through electronic switch 6.This sampled signal through filter unit 7, hinder signal demodulation and A/D converter 8 and ground resistance signal amplifier 3 is sent into control module 10, in control module 10, earlier the sampled signal of input is carried out digital filtering, again it is carried out analyzing and processing, display device 11 is stored and passed to the grounding resistance that obtains show.This filter unit 7 comprises RC filtering circuit and the phase-locked loop circuit that is linked in sequence, this phase-locked loop circuit is followed the tracks of detection synchronously, make the test signal sent and the feedback signal of reception not produce frequency deviation, other interfering frequency signals can't be scurried into, weakened the interference of other ground vapour clutters.Also be provided with the data communication mouth on this control module 10, can realize and being connected of other monitoring systems, thereby realize the remote monitoring monitoring by this data communication mouth.

Claims (4)

1, a kind of multi-point simultaneous-measurement digital grounding resistance tester is characterized in that comprising:
One Switching Power Supply, this Switching Power Supply comprise first output terminal and second output terminal, and this Switching Power Supply is used for civil power 220V alternating current is converted into the required low-voltage DC of tester;
One resistance measurement reference power supply, its input end is connected with second output terminal of Switching Power Supply, and its output terminal is connected with the reference signal input end of ground resistance signal amplifier, thereby provides a reference signal for ground hinders signal amplifier;
One pulse signal generator, it has a plurality of pulse signal output ends, the full sized pules signal that those output terminal output frequencies are 550Hz;
One power inverter, its input end is connected with first output terminal of Switching Power Supply, its trigger end is connected with a pulse signal output end of pulse signal generator, it is under the full sized pules signal triggering of 550Hz in the frequency that pulse signal generator sends, the direct current of Switching Power Supply first output terminal output is modulated the envelope AC signal that changes frequency 550Hz and current constant into, to provide test required constant current source;
One electronic switch, the tested electrode of its external a plurality of usual disconnections and a potential electrode and a testing current electrode, the input end of this electronic switch connects the output terminal of power inverter, this electronic switch also comprises the voltage sample unit that can sample to voltage between tested electrode and the potential electrode, the sampled signal of this voltage sample unit output is through the sampled voltage output terminal output of electronic switch, during test, under control module control, electronic switch switches between a plurality of tested electrodes, respectively different tested electrodes are connected, make and hinder test point a plurality ofly and alternately insert in the loop, realize the ground resistance of a plurality of different ground wires is tested;
One filter unit, it comprises RC filtering circuit and phase-locked loop circuit, the input end of this filter unit is connected with the sampled voltage output terminal of electronic switch;
Resistance signal demodulation of one ground and A/D converter, its input end connects the output terminal of filter unit, and the demodulation of filtered analog quantity sampled voltage signal is converted into pulsation shape digital sample voltage signal;
One ground resistance signal amplifier, its input end connects the output terminal of demodulation and A/D converter, and the shape digital sample voltage signal of will pulsing amplifies earlier, proofreaies and correct and checks and approves, and is transported to control module then;
One control module, its input end connects the output terminal of ground resistance signal amplifier, its output terminal is connected with electronic switch and display device, this control module output instruction signal is given electronic switch, electronic switch is switched between different tested electrodes, this control module also comprises digital filter apparatus and can be according to the APU of sampled voltage calculated signals ground resistance, earlier carry out digital filtering from the digital sample voltage signal of ground resistance signal amplifier Input Control Element through digital filter apparatus, treating apparatus calculates stake resistance by analysis again, and this stake resistance stored, and send display device to and show.
2, multi-point simultaneous-measurement digital grounding resistance tester according to claim 1 is characterized in that, also is provided with the data communication mouth on the described control module.
3, multi-point simultaneous-measurement digital grounding resistance tester according to claim 1 is characterized in that, described control module is a robot calculator.
4, multi-point simultaneous-measurement digital grounding resistance tester according to claim 1 is characterized in that, described control module is a single-chip microcomputer.
CN2009200648945U 2009-06-24 2009-06-24 Multi-point synchronous measurement type digital grounding resistance tester Expired - Fee Related CN201434893Y (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102279244A (en) * 2011-05-10 2011-12-14 中安金力(北京)安全生产技术研究院 Multi-parameter sensor for entry lock
CN106705832A (en) * 2017-02-21 2017-05-24 辽宁省交通规划设计院有限责任公司 Bridge pier scouring detection system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102279244A (en) * 2011-05-10 2011-12-14 中安金力(北京)安全生产技术研究院 Multi-parameter sensor for entry lock
CN106705832A (en) * 2017-02-21 2017-05-24 辽宁省交通规划设计院有限责任公司 Bridge pier scouring detection system

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Granted publication date: 20100331

Termination date: 20120624