CN108152595A - A kind of earth mat class power-frequency earthing impedance instrument and test method - Google Patents
A kind of earth mat class power-frequency earthing impedance instrument and test method Download PDFInfo
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- CN108152595A CN108152595A CN201711312756.XA CN201711312756A CN108152595A CN 108152595 A CN108152595 A CN 108152595A CN 201711312756 A CN201711312756 A CN 201711312756A CN 108152595 A CN108152595 A CN 108152595A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/20—Measuring earth resistance; Measuring contact resistance, e.g. of earth connections, e.g. plates
- G01R27/205—Measuring contact resistance of connections, e.g. of earth connections
Abstract
The invention discloses a kind of earth mat class power-frequency earthing impedance instruments, including alien frequencies crossing current power supply, current amplifier and voltage amplifier, the alien frequencies constant-current source output variable frequency test electric current；The current amplifier gives wave filter I after obtaining current signal and amplification from current transformer, wave filter II is given after the voltage amplification of the voltage amplifier collection voltages input terminal, electric current and voltage after filtered device I and wave filter II filterings send microcontroller to by A/D converter, contain storage unit in the microcontroller, for preserving each test data, also disclose the test method of the earth mat class power-frequency earthing impedance based on the tester, it is small with test error, the advantages of precision is accurate, strong antijamming capability.
Description
Technical field
The present invention relates to a kind of mesh grounding impedance instrument and test methods, belong to earth mat class power-frequency earthing testing impedance
Technical field.
Background technology
The test job of country's earthing or grounding means is weaker at present, some crucial Technologies And Conceptions are relatively fuzzyyer, technology hand
After paragraph.For above-mentioned present situation, China has worked out newest professional standard DL/T475-2006 and standard GB/T/T17949.1-
2000.New standard has done old plant many material alterations.
Class power-frequency earthing impedance refers to potential difference of the earthing or grounding means between the zero potential point of a distant place with being flowed by earthing or grounding means
The ratio of class power current in ground.The impedance of class power-frequency earthing was habitually known as " class power frequency earthing resistance " in the past.This title
Correction, in standard GB/T/T17949.1-2000, " soil resistivity of earthed system, impedance ground and ground potential measure
Directive/guide first part：General measure " and power industry standard " earthing or grounding means characterisitic parameter measures directive/guide revised draft " (substitution
DL475-92 it is set forth in).The measuring instrument is tested using alternating current, therefore surveyed numerical value is known as impedance ground, without
Previous address " ground resistance " is continued to use again.
When being measured to earthing or grounding means, due to by the various interference such as uneven zero-sequence current and radio frequency so that survey
Test result generates very big error.The general very little of impedance ground (generally in 0.5 below Ω) of particularly large-scale grounding network, interference
The relative error bigger brought.In order to reduce the influence of scene interference, there are mainly two types of the methods used at present, and one kind is increase
Electric current is tested, one kind is to use alien frequencies method.First method is to test electric current by increasing to increase signal voltage and signal electricity
Stream so as to improve signal-to-noise ratio, reduces measurement error.This method is as a result of very big test electric current (DL/T475-2006
Standard recommendation is not preferably less than 50A) so that equipment is very heavy, and wiring labor intensity is very big, takes time and effort.It is moreover, because main
It interferes with signal with frequency, the influence of interference can not be inherently eliminated.Alien frequencies rule is that the frequency of electric current is tested by change
Class Hz noise is avoided, since signal frequency is different from interfering frequency, it is possible to filter out the influence of interference by wave filter,
So as to improve measurement accuracy.For alien frequencies method since the test electric current of use is smaller, equipment is compact, connects up labor intensity also significantly
Mitigate.Due to having the advantages that test result is reliable and stable and time saving and energy saving, alien frequencies method test is connect extensively by domestic and international expert
By and use, but power-frequency earthing impedance be impedance of the grounding body under power current, alien frequencies method use test power frequency not
For power frequency, so measurement result equivalence is poor, it is difficult to meet the requirement of electric system regulation regulation.
According to definition, class power-frequency earthing impedance refers to the impedance that earthing or grounding means shows under class power current, and alien frequencies
The test power frequency that method uses not for class power frequency, therefore the numerical value measured will and power current under the value that measures have deviation.
The reason of theory and practice shows to generate deviation is that the impedance ground of earthing or grounding means is complex impedance, not only comprising resistive point
Amount, also containing the inductive and capacitive component related with frequency, the test frequency of use differs more remote then equivalent with class power frequency
Property it is poorer, i.e. measurement error is bigger, in order to ensure test accuracy, test frequency cannot be too wide in the gap with class power frequency, and survey
The waveform of examination electric current should be sine wave (other waveforms such as square wave contains abundant harmonic frequency).Early in the seventies, the U.S., Japan
States is waited just to define the difference of test frequency and class power frequency no more than 10Hz.Chinese national standard GB/T17949.1-2000 requirements
Test power frequency should as possible close to class power frequency, professional standard DL/T475-2006 define test power frequency preferably 40~
Between 60Hz.
But data of current instrument test or bigger, particularly there is situation existing for other harassing and wrecking frequencies
Under, test data can be more inaccurate.
Invention content
The object of the present invention is to provide a kind of earth mat class power-frequency earthing impedance instrument and test methods, are surveyed using alien frequencies method
Amount, and with reference to filtering technique so that the advantages of instrument has very high interference free performance, and test data is reliable and stable.
The technical solution that the present invention takes is：
A kind of earth mat class power-frequency earthing impedance instrument, including alien frequencies crossing current power supply, current amplifier and voltage amplifier,
The alien frequencies constant-current source output variable frequency test electric current；The current amplifier obtains current signal from current transformer and puts
Wave filter I is given after big, wave filter II, filtered device are given after the voltage amplification of the voltage amplifier collection voltages input terminal
Electric current and voltage after I and wave filter II filterings send microcontroller to by A/D converter, contain in the microcontroller and deposit
Storage unit, for preserving each test data；Wave filter I and wave filter II be used for filtering interference signals, only allow 45Hz and
55Hz signals pass through so that instrument has very high interference free performance, and test data is reliable and stable.
Preferential, the voltage amplifier is high input impedance amplifier.
Preferential, it is exported after the filtered device filtering of test electric current of the alien frequencies constant-current source output through current output terminal mouth,
The electric current of output is isolated, prevents output current from being ensured the correctness of the test frequency of output current by external interference.
Preferably, the current output terminal mouth and control source port are respectively two, current transformer and one of them
Current output terminal mouth is connected.
Preferably, the microcontroller is keyed with mini-printer, liquid crystal display, alarm and at least one press,
When circuit breaking, microcontroller control alarm equipment alarm avoids wrong measurement, when a failure occurs, alarm text importing
The reason of breaking down does not send out alarm sound.
Preferably, the microcontroller is communicated with background computer, and the data of detection are uploaded to computer in real time, is realized
The function of on-line real-time measuremen.
Preferably, the adjustable sine wave that the alien frequencies constant-current source output frequency is 45Hz or the virtual value of 55Hz is 1-3A is surveyed
Electric current is tried, the potential rise of earthing or grounding means to be measured is too high when will not cause test.
Preferably, the microcontroller and 4 are by key connection, including：
Upward arrow key is used to increase number or moves up cursor；
Down Arrow is used to reduce number or moves down cursor；
Cursor key is used to move cursor；
Acknowledgement key is used to confirm the order at the data inputted or execution cursor.
Preferably, the microcontroller passes through RS232 communication interfaces and computer communication.
Preferably, the described tester further includes instrument panel and electric power connecting head, power switch, passes through electric power connecting head
It powers for the tester.
Preferably, the current output terminal mouth, control source port, button, liquid crystal display, mini-printer, power supply
Connection-peg, power switch are installed on instrument panel.
Preferably, power switch is switched for ship type, is powered on upwards for tester.
Preferably, earth mat class power frequency is 50HZ.
Based on a kind of earth mat class power-frequency earthing impedance detecting method of earth mat class class power-frequency earthing impedance instrument, including with
Lower step：
The test loop of earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance；
Current output terminal and voltage input end access the test loop of earthing or grounding means to be measured；
Alien frequencies constant-current source exports the test electric current under test frequency；
Measure voltage V, electric current I and its phase difference chosen under test frequency；
Class power-frequency earthing impedance Z, resistive component R and electricity are calculated according to measured voltage V, electric current I and its phasometer
Anti- component X；
Using the class power-frequency earthing impedance value under different test frequencies, class power-frequency earthing decision value is calculated；
The data of measurement are uploaded into computer in real time, realize on-line real-time measuremen.
The test that earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance
Circuit, including following sub-step：
Select current voltage meter straight line three electrode method arrangement test loop, potential pole test cable and electric current pole test cable
Between angle be zero；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively；
The wire laying mode that the test loop cable is used for a long time using buried primary wiring, uses buried wiring
It does not need to repeat to connect up when being to test again, mitigates tester's labor intensity, reduce testing cost.
The test that earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance
Circuit, including following sub-step：
Select electric current pole, potential pole angle-off set arrangement test loop, during angle-off set, potential pole test cable and electric current pole are surveyed
The angle tried between cable is 30 °；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively；
The wire laying mode that the test loop cable is used for a long time using buried primary wiring, uses buried wiring
It does not need to repeat to connect up when being to test again, mitigates tester's labor intensity, reduce testing cost.
The current output terminal and voltage input end access the test loop of earthing or grounding means to be measured, including following sub-step：
Current output terminal mouth C1 is connect with the Current injection points of earthing or grounding means to be measured, control source port P1 and ground connection to be measured
The voltage test points connection of device；
Current output terminal mouth C2 is connect using current line with electric current pole, and control source port P2 utilizes equipotential line and potential pole
Connection, current transformer are concatenated with output port of power source C2.
The alien frequencies constant-current source exports the test electric current under test frequency, to automatically select the virtual value of 45HZ or 55HZ
Adjustable sine wave for 1-3A tests electric current.
The determining electric current pole and the position of potential pole, including following sub-step：
The distance of electric current pole and tested earthing or grounding means is more than 4 times of tested earthing or grounding means maximum diagonal length D；
Potential pole selects the position for meeting compensation condition in infinite approach, and the compensation condition is：
It is described to calculate class power-frequency earthing impedance Z, resistive component R according to measured voltage V, electric current I and its phasometer
With reactive component X, including following sub-step：
If it is unsatisfactory for compensation conditionThe class power-frequency earthing then calculated
Impedance needs to be modified using the following formula：
In formula, Z '=V/I is instrument measurements, and D is to be tested earthing or grounding means maximum diagonal length, dCGIt is electric current pole with connecing
The distance at ground device edge, dPGFor the distance of potential pole and earthing or grounding means edge, θ is the angle of current line and equipotential line；
Such as meet compensation conditionIt does not need to then correct；
Automatically compensation makes geodetic network's impedance ground data that can more accurately contract to potential pole data for the test method of zero potential
Short test loop wiring distance, position current potential extremely 0 current potential of 4 × D of network edge (D is earth mat catercorner length) distance on ground,
It is not then 0 current potential to shorten test loop cable wiring apart from potential pole, and earthing or grounding means test loop to be measured is automatically by current potential at this time
Pole compensation is 0 current potential, ensures that test data is accurate.
Beneficial effects of the present invention：1. the impedance of class power-frequency earthing, contact that tester can be to all kinds of earthing or grounding means to be measured
The classes power frequency characterisitic parameters such as voltage, step voltage, transfer current potential, surface potential gradient in place to be measured and soil resistivity carry out
Test；
2. the present invention can accurately measure the number under class power frequency 50Hz using alien frequencies Anti-Jamming Technique under strong interference environment
According to；Test electric current is smaller, and the current potential of earthing or grounding means is excessively high when will not cause test, while it also has extremely strong anti-interference energy
Power, test data are reliable and stable；
3. the class power frequency equivalence measured is good.Test current waveform is sine wave, and the difference of frequency and class power frequency is only 5Hz,
It is measured using two kinds of frequencies of 45Hz and 55Hz, error is very small, and precision is high.
Description of the drawings
Fig. 1 is earth mat class power-frequency earthing impedance instrument system block diagram
Fig. 2 is the test wiring diagram of embodiment two；
Fig. 3 is the test wiring diagram of example IV；
Fig. 4 is the test wiring diagram of embodiment five；
Fig. 5 is the test wiring diagram of embodiment six.
Wherein：The power supply 1. alien frequencies flows over；2. current transformer；3. current amplifier；4；Voltage amplifier；5. wave filter I；
6. wave filter II；7.A/D converters；8. microcontroller；9. liquid crystal display；10. mini-printer；11.R232 communication interfaces.
Specific embodiment
The invention will be further described with preferred embodiment below in conjunction with the accompanying drawings.
Embodiment one
As shown in Figure 1, a kind of earth mat class power-frequency earthing impedance instrument, including alien frequencies crossing current power supply 1, current amplifier 3
With voltage amplifier 4, the alien frequencies constant-current source 1 exports variable frequency test electric current；The current amplifier 3 is from current transformer
Wave filter I5 is given after 2 acquirement current signals and amplification, is sent after the voltage amplification of the 4 collection voltages input terminal of voltage amplifier
The electric current and voltage given after wave filter II6, filtered device I5 and wave filter II6 filtering send microcontroller to by A/D converter 7
Device 8；Contain storage unit in the microcontroller 8, for preserving each test data；The voltage amplifier 4 is high defeated
Enter impedance amplifier, exported after the filtered device filtering of the test electric current that the alien frequencies constant-current source 1 exports through current output terminal mouth；Institute
It is respectively two to state current output terminal mouth and control source port, and current transformer is connected with one of current output terminal mouth；
The microcontroller 8 is connect with mini-printer 10, liquid crystal display 9 and alarm；When a failure occurs it, alarm display event
Hinder reason, fault alarm sound will not be sent out；The sine wave test electricity that 1 output frequency of alien frequencies constant-current source is 45Hz or 55Hz
Stream；The microcontroller 8 and 4 by key connection, including：
Upward arrow key is generally used for increasing number or moves up cursor；
Down Arrow is generally used for reducing number or moves down cursor；
Cursor key is mainly used for mobile cursor；
Acknowledgement key is mainly used for confirming the order at the data inputted or execution cursor.
The data of detection are uploaded to calculating by microcontroller 8 in real time by RS232 communication interfaces 11 and computer communication
Machine, realizes on-line real-time measuremen, and the described tester further includes instrument panel and electric power connecting head, power switch, passes through power supply
Connection-peg is powered for the tester；The current output terminal mouth, control source port, button, liquid crystal display 9, microprinting
Machine 10, electric power connecting head, power switch are installed on instrument panel, and power switch is switched for ship type, is connect upwards for tester
Energization source, earth mat class power frequency are 50HZ.
Embodiment two
As shown in Fig. 2, G is earthing or grounding means to be measured, P is potential pole, and C is electric current pole；
A kind of test method using the test earth mat class power-frequency earthing impedance of earth mat class power-frequency earthing impedance instrument, including
Following steps：
The test loop of earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance；
Tester is accessed to the test loop of earthing or grounding means to be measured using current output terminal mouth and control source port；
Alien frequencies constant-current source exports the test electric current under test frequency；
Measure voltage V, electric current I and its phase difference chosen under test frequency；
Class power-frequency earthing impedance Z, resistive component R and electricity are calculated according to measured voltage V, electric current I and its phasometer
Anti- component X；
Using the class power-frequency earthing impedance value under different test frequencies, class power-frequency earthing decision value is calculated；
The data of detection are uploaded into computer in real time, realize the function of on-line real-time measuremen.
The test that earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance
Circuit, including following sub-step：
Select current voltage meter straight line three electrode method arrangement test loop, voltage pole test cable and electric current pole test cable
Between angle be zero；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively；
The wire laying mode that the test loop cable is used for a long time using buried primary wiring, uses buried wiring
It does not need to repeat to connect up when being to test again, mitigates tester's labor intensity, reduce testing cost.
The test that earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance
Circuit, including following sub-step：
Select electric current pole, potential pole angle-off set arrangement test loop, during angle-off set, potential pole test cable and electric current pole are surveyed
The angle tried between cable is 30 °；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively.
The test loop that tester is accessed to earthing or grounding means to be measured using current output terminal mouth and control source port,
Including following sub-step：
Current output terminal mouth C1 is connect with the Current injection points of earthing or grounding means to be measured, control source port P1 and ground connection to be measured
The voltage test points connection of device；
Current output terminal mouth C2 is connect using current line with electric current pole, and control source port P2 utilizes equipotential line and potential pole
Connection, current transformer are concatenated with output port of power source C2；
The alien frequencies constant-current source exports the test electric current under test frequency, to automatically select the virtual value of 45HZ or 55HZ
Adjustable sine wave for 1-3A tests electric current.
The determining electric current pole and the position of potential pole, including following sub-step：
The distance of electric current pole and tested earthing or grounding means is more than 4 times of tested earthing or grounding means maximum diagonal length D；
Potential pole selects the position for meeting compensation condition in infinite approach, and the compensation condition is：
It is described to calculate class power-frequency earthing impedance Z, resistive component R according to measured voltage V, electric current I and its phasometer
With reactive component X, including following sub-step：
If it is unsatisfactory for compensation conditionThe class power-frequency earthing then calculated
Impedance needs to be modified using the following formula：
In formula, Z '=V/I is instrument measurements, and D is to be tested earthing or grounding means maximum diagonal length, dCGIt is electric current pole with connecing
The distance at ground device edge, dPGFor the distance of potential pole and earthing or grounding means edge, θ is the angle of current line and equipotential line；
Such as meet compensation conditionIt does not need to then correct；
Automatically compensation makes geodetic network's impedance ground data that can more accurately contract to potential pole data for the test method of zero potential
Short test loop wiring distance, the position electricity of 4 × D of network edge (D is tested earthing or grounding means maximum diagonal length) distance on ground
Position extremely 0 current potential, it is not then 0 current potential to shorten test loop cable wiring apart from potential pole, and earthing or grounding means to be measured is tested back at this time
Potential pole compensation is automatically 0 current potential by road, ensures that test data is accurate.
Embodiment three
The test of place surface potential gradient is carried out using tester, step includes：
Step 1：A pile is being made a call to as electric current pole from earthing or grounding means predeterminated position to be measured, and predeterminated position refers to the electric current
Pole is still taken as 4 times more than earthing or grounding means maximum diagonal length D to be measured with a distance from earthing or grounding means edge to be measured；Selection one
The down conductor of good earthing or grounding means to be measured be can contact as Current injection points, with conducting wire by the C1 terminals of instrument panel and electricity
Streamer access point is reliably connected, then is reliably connected the C2 terminals of instrument panel with electric current pole with conducting wire；
Step 2：By tested place classifying rationally, tested place Potential distribution is stated with several curves；On curve road
Middle part select one on diameter and the good down conductor of major network connection is reference point, and the reference point is connected to test with conducting wire
The P1 terminals of instrument first by potential pole as the starting point of curve, and are wired to the P2 terminals of tester；
Step 3：Tester power switch is opened, after selection performs " contact potential, step voltage " function menu, liquid crystal
9 input system single-phase earth fault current Is screens of display, are configured according to real system single-phase earth fault current；Confirm
Afterwards, tester prompting setting test size of current, may be selected to be " automatic ", 0.2A, 0.5A, 1.0A, 2.0A, 3.0A；
Step 4：Tester starts to measure, and shows voltage value U, record position and the voltage data measured.
Step 5：Since the starting point of the curve, equidistantly with migration potential pole, step 3 and step 4 are repeated, until
End of Curve measures multiple positions and voltage data, these data are depicted as U-x curves to get to a Potential distribution song
Line；
Step 6：Curve is replaced, step 1 to step 5 is repeated and measures whole curves.
When spacing d is taken as 1m, the potential difference on the surface potential curve of place between adjacent 2 points is real system event
Unit place surface potential gradient U during barrierT；Crooked chisel can be used in potential pole P, if test place is cement pavement, using packet
Wrap up in the rosette of the diameter 20cm of wet cloth, and ballast.
Example IV
As shown in figure 3, G be earthing or grounding means to be measured, S be equipment framework, C be electric current pole, PbTo simulate the metallic plate of people's foot
Electrode, RmFor equivalent human body resistance, Rm does not access test loop when measuring contact electromotive force.
Contact voltage, contact electromotive force are measured using tester, step includes：
Step 1：A pile is being made a call to as electric current pole from earthing or grounding means predeterminated position to be measured, and predeterminated position refers to the electric current
Pole is still taken as 4 times that are more than tested earthing or grounding means maximum diagonal length D with a distance from earthing or grounding means edge to be measured；
Step 2：Electric current output port C2 on the instrument panel of tester is reliably connected with electric current pole with conducting wire, with leading
Current output terminal mouth C1 terminals are connected to equipment framework by line；
Step 3：The control source port P1 of tester is connected to the Pa points on equipment framework, and Pa is 1.8 away from ground level
Rice；
The control source interface P2 of tester is connected to the plate electrodes P of simulation people's footbOn, the electrode is using package wet cloth
The rosette of a diameter of 20cm, and press upper weight；Electrode PbCentre-to-centre spacing equipment framework S Edge Distances are 1 meter；
Step 4：Parallel equivalent human body resistance Rm between tester control source port P1 and P2 are straight when measuring contact voltage,
Generally take Rm=1.5K Ω；Rm is not met when measuring contact electromotive force；
Step 5：After detection wiring is errorless, tester power supply is connected, selection performs " contact potential, step voltage " function
Menu；It is prompted according to tester, setting system short-circuit fault electric current Is starts and measures with after test electric current；
Step 6：Measurement finishes, and the contact voltage measured or contact potential difference U are shown on liquid crystal display 9.
Embodiment five
As shown in figure 4, G be earthing or grounding means to be measured, S be equipment framework, C be electric current pole, Pc、PdTo simulate the metal of people's foot
Plate electrode, RmFor equivalent human body resistance, Rm does not connect when measuring step potential difference；
The measuring method of step potential difference and step voltage is carried out using tester, is included the following steps：
Step 1：A pile is being made a call to as electric current pole from earthing or grounding means predeterminated position to be measured, and predeterminated position refers to the electric current
Pole is more than 4 times of earthing or grounding means maximum diagonal length D with a distance from earthing or grounding means edge to be measured；
Step 2：The instrument panel current output terminal mouth C2 of tester is reliably connected with electric current pole with conducting wire；Use conducting wire
The current output terminal mouth C1 of tester is connected to the down conductor of equipment framework；
Step 3：Control source interface P1, P2 of tester are respectively connected to the plate electrodes P of simulation people's footc、Pd, electrode
Pc、PdUsing the rosette of a diameter of 20cm of package wet cloth, and press upper weight；PcAnd PdElectrode centers distance is 1 meter；
When measuring step voltage, parallel equivalent human body resistance Rm between tester control source interface P1 and P2 takes Rm=
1.5KΩ；
Step 4：After detection wiring is errorless, tester power supply is connected, selection performs " contact voltage, step voltage " function
Menu；It is prompted according to tester, setting system short-circuit fault electric current Is and test electric current start test；
Step 5：Measurement finishes, and the step potential difference measured or step voltage U are shown on liquid crystal display 9k。
Embodiment six
As shown in figure 5, four test electrode arrangements are on straight line, a is the spacing of electric current pole and potential pole, b two
The spacing of potential pole, h are the electrode depth of burying；As quadrupole method of equal intervals or Wenner method as a=b；For ease of calculating, please allow
Electrode spacing a, b is more than depth of burying h, meets a, b>10h；
It is not small using round steel of the diameter not less than 15mm or the angle steel of 25mm × 25mm × 4mm, length to test electrode
In 40cm；
Tester measures the test method of soil resistivity, and step is：
Step 1：Embedded electrode, at the same by two current output terminal mouths C1 and C2 of tester respectively with two electric current poles
Connection, the control source port P1 and P2 of tester are connect respectively with two potential poles；
The distance a of electric current best potential pole and two potential pole spacing b, if b values are less than 0.1m, tester will move out measurement；
Step 2：Correct setting electrode spacing parameter, setting test electric current, tester start test；
Step 3：Measurement finishes, and liquid crystal display 9 shows soil resistivity.
During more than wiring, the resistance of current line can increase loop resistance, and in order to reduce the resistance of current line, current line is selected
Thicker current line；Microampere order electric current is flowed only through in pressure-wire, therefore without considering its through-current capability；Conducting wire should have good
Insulation sheath during adjunction conducting wire, needs to wrap tie point using insulating tape.
The explanation of above example is only intended to facilitate the understanding of the method and its core concept of the invention；Meanwhile for this
The those skilled in the art in field, thought according to the present invention, there will be changes in specific embodiments and applications,
In conclusion the content of the present specification should not be construed as limiting the invention.
Claims (10)
1. a kind of earth mat class power-frequency earthing impedance instrument, which is characterized in that including alien frequencies crossing current power supply, current amplifier and electricity
Press amplifier, the alien frequencies constant-current source output variable frequency test electric current；The current amplifier obtains electricity from current transformer
Wave filter I is given after stream signal and amplification, wave filter is given after the voltage amplification of the voltage amplifier collection voltages input terminal
Electric current and voltage after II, filtered device I and wave filter II filtering send microcontroller, the micro-control to by A/D converter
Contain storage unit in device processed, for preserving each test data.
2. tester as described in claim 1, which is characterized in that the voltage amplifier is high input impedance amplifier.
3. tester as described in claim 1, which is characterized in that the filtered device of test electric current of the alien frequencies constant-current source output
It is exported after filtering through current output terminal mouth；The alien frequencies constant-current source output frequency be 45Hz or the virtual value of 55Hz be 1-3A can
Adjust sine wave test electric current；The current output terminal mouth and control source port are respectively two, the current transformer and its
In the series connection of current output terminal mouth.
4. tester as described in claim 1, which is characterized in that the microcontroller and mini-printer, liquid crystal display,
Alarm and at least one press are keyed, and detection data is uploaded to meter by the microcontroller and computer real-time communication in real time
Calculation machine realizes that data detect in real time.
5. tester as claimed in claim 4, which is characterized in that the microcontroller and 4 by key connection, including：
Upward arrow key is used to increase number or moves up cursor；
Down Arrow is used to reduce number or moves down cursor；
Cursor key is used to move cursor；
Acknowledgement key is used to confirm the order at the data inputted or execution cursor.
6. a kind of earth mat class power-frequency earthing impedance detecting method, which is characterized in that include the following steps：
The test loop of earthing or grounding means to be measured is arranged according to the test mode of prespecified test class power-frequency earthing impedance；
Current output terminal and voltage input end access the test loop of earthing or grounding means to be measured；
Alien frequencies constant-current source exports the test electric current under test frequency；
Measure voltage V, electric current I and its phase difference chosen under test frequency；According to measured voltage V, electric current I and its phase
Difference calculates class power-frequency earthing impedance Z, resistive component R and reactive component X；
Using the class power-frequency earthing impedance value under different test frequencies, class power-frequency earthing decision value is calculated；
The data of detection are uploaded into computer in real time, realize the function of on-line real-time measuremen.
7. test method as claimed in claim 6, which is characterized in that described according to prespecified test power-frequency earthing impedance
Test mode arrange the test loop of earthing or grounding means to be measured, including following sub-step：Select three pole of current voltage meter straight line
Method arranges test loop, and the angle between pressure-wire and current line is zero；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively；
The wire laying mode that the test loop cable is used for a long time using buried primary wiring.
8. test method as claimed in claim 6, which is characterized in that described to be hindered according to prespecified test class power-frequency earthing
Anti- test mode arranges the test loop of earthing or grounding means to be measured, including following sub-step：
Select electric current pole, potential pole angle-off set arrangement test loop, during angle-off set, potential pole test cable and electric current pole p-wire
Angle between cable is 30 °；
Determine the Current injection points and voltage test points in the test loop of earthing or grounding means to be measured；
It determines electric current pole and the position of potential pole, is driven underground as the pile of electric current pole and potential pole respectively；
The wire laying mode that the test loop cable is used for a long time using buried primary wiring.
9. test method as claimed in claim 6, which is characterized in that the current output terminal and voltage input end access are to be measured
The test loop of earthing or grounding means, including following sub-step：
Current output terminal mouth C1 is connect with the Current injection points of earthing or grounding means to be measured, control source port P1 and earthing or grounding means to be measured
Voltage test points connection；
Current output terminal mouth C2 is connect using current line with electric current pole, and control source port P2 is connected using equipotential line and potential pole
It connects.
10. test method as claimed in claim 6, which is characterized in that described according to measured voltage V, electric current I and its phase
Potential difference calculates class power-frequency earthing impedance Z, resistive component R and reactive component X, including following sub-step：
If it is unsatisfactory for compensation conditionThe class power-frequency earthing impedance then calculated needs
It to be modified using the following formula：
In formula, Z '=V/I is instrument measurements, and D is to be tested earthing or grounding means maximum diagonal length, dCGIt is filled for electric current pole and ground connection
Put the distance at edge, dPGFor the distance of potential pole and earthing or grounding means edge, θ is the angle of current line and equipotential line；
Such as meet compensation conditionIt does not need to then correct.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109470930A (en) * | 2018-10-24 | 2019-03-15 | 国网四川省电力公司电力科学研究院 | A kind of measurement method of earthing or grounding means impedance ground spectral characteristic |
| CN110749777A (en) * | 2019-12-02 | 2020-02-04 | 广西地凯科技有限公司 | Soil resistivity measuring method |
| CN112014618A (en) * | 2020-07-27 | 2020-12-01 | 深圳供电局有限公司 | Contact voltage detection device, grounding system and contact voltage detection method |
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| CN112083254A (en) * | 2020-09-18 | 2020-12-15 | 西南交通大学 | Electrical injury damage evaluation method considering differentiation of human body pressure |
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| CN203299282U (en) * | 2013-06-27 | 2013-11-20 | 武汉豪迈电气设备有限公司 | Grounding impedance tester |
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| CN203299282U (en) * | 2013-06-27 | 2013-11-20 | 武汉豪迈电气设备有限公司 | Grounding impedance tester |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109470930A (en) * | 2018-10-24 | 2019-03-15 | 国网四川省电力公司电力科学研究院 | A kind of measurement method of earthing or grounding means impedance ground spectral characteristic |
| CN109470930B (en) * | 2018-10-24 | 2021-01-22 | 国网四川省电力公司电力科学研究院 | Method for measuring frequency spectrum characteristic of grounding impedance of grounding device |
| CN110749777A (en) * | 2019-12-02 | 2020-02-04 | 广西地凯科技有限公司 | Soil resistivity measuring method |
| CN112014618A (en) * | 2020-07-27 | 2020-12-01 | 深圳供电局有限公司 | Contact voltage detection device, grounding system and contact voltage detection method |
| CN112014619A (en) * | 2020-07-27 | 2020-12-01 | 深圳供电局有限公司 | Step voltage detection device, grounding system and step voltage detection method |
| CN112285456A (en) * | 2020-09-16 | 2021-01-29 | 云南电网有限责任公司昆明供电局 | Potential-based ground grid uncertainty measuring method |
| CN112083254A (en) * | 2020-09-18 | 2020-12-15 | 西南交通大学 | Electrical injury damage evaluation method considering differentiation of human body pressure |
| CN112083254B (en) * | 2020-09-18 | 2021-06-29 | 西南交通大学 | Electrical injury damage evaluation method considering differentiation of human body pressure |
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