CN107765099A - A kind of broadband test apparatus and method for being used to measure grounding body impedance - Google Patents
A kind of broadband test apparatus and method for being used to measure grounding body impedance Download PDFInfo
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- CN107765099A CN107765099A CN201710979429.3A CN201710979429A CN107765099A CN 107765099 A CN107765099 A CN 107765099A CN 201710979429 A CN201710979429 A CN 201710979429A CN 107765099 A CN107765099 A CN 107765099A
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Abstract
The present invention discloses a kind of broadband test device for being used to measure grounding body impedance, including the driving source based on simulation PI regulations；Driving source based on simulation PI regulations includes AC/DC converters, DC/AC converters, pi regulator, SPWM and comparator；The input of AC/DC converters is the input of the driving source based on simulation PI regulations；The input of the output end connection DC/AC converters of AC/DC converters, the output end of DC/AC converters is as the output end based on the driving source for simulating PI regulations；The first input end of the output end connection comparator of DC/AC converters, the second input of the output end connection comparator of given circuit, the input of the output end connection pi regulator of comparator, the control terminal of the output end connection AC/DC converters of pi regulator；The output end of the input connection DC/AC converters of controller based on DSP, two output ends of the controller based on DSP connect given circuit and SPWM input respectively；The control terminal of SPWM output end connection DC/AC converters.More a width of 20Hz~the 30kHz of frequency band that the present invention exports.
Description
Technical field
The present invention relates to grid grounding impedance measurement field, more particularly to a kind of broadband test for being used to measure grounding body impedance
Apparatus and method.
Background technology
Grounded screen is laid on underground and is in close contact with soil, oxygen, acid solution, stray electrical current and microorganism in soil
Deng there is certain corrosion function to grounded screen.The soil characteristic of different regions is also not quite similar with composition, and it is to grounded screen
Corrosive power also not to the utmost just as.Therefore, the running status of grounded screen is monitored and perceived, and it is timely safeguarded electric to ensureing
The reliability service of equipment is particularly important with supplying Electrical Safety.And the impedance operator of grounded screen turns into sign and perceives ground connection network operation
The only resource of state.Because a large amount of power frequency electromagnet interference, and the signal line transmission distance tested be present in grounded screen measure field
From interference is very big between each other farther out, it is desirable to which tester will have output current as big as possible, that is, ensure whole tester
Power it is sufficiently large, to ensure the antijamming capability of whole test process.
With the continuous development of test e measurement technology, earth loop impedance test method and earth loop impedance test instrument all have passed through not
Disconnected development and improvement.Successively there is hand-rail type ohmmeter, pincerlike ohmmeter and the high-power impedance test system of frequency conversion etc..Become
Frequently high-power impedance test system is tested according to alien frequencies method, it is desirable to electric current is tested in 3A~20A, frequency 40Hz~
60Hz.Test electric current as big as possible is used to ensure the antijamming capability of test process, using be easy to power frequency and as far as possible connect
The measurement frequency of power frequency is bordering on, detection and its test result for being convenient for measuring result are very close again and under the conditions of power frequency.
But with to the side such as Fault Diagnosis for Grounding Grids, the prediction of ground net corrosion speed and earthing material characteristic test
The research in face is goed deep into, the intermediate frequency and high frequency characteristics of the more deep understanding grounded screen of people's urgent need.It is also required to simultaneously
By the further investigation of this aspect, the system in revision IEEE/GB progressively in terms of ground mat construction and grid grounding impedance measurement
One standard.Wherein main test target is the characteristic near the intermediate frequency i.e. 1kHz for testing grounded screen and near high frequency 30kHz.
But under the requirement of such test frequency, completed using the means of signal amplification, its test equipment volume
Greatly, power output is small, antijamming capability is also poor.
The content of the invention
Be used to measure the broadband test apparatus and method of grounding body impedance it is an object of the invention to provide a kind of, with gram
Take the problem of existing frequency conversion test equipment frequency range is narrow.The present invention designs a kind of portable, intelligence by introducing converter technique
Energyization, wideband, powerful earth loop impedance test equipment, while test frequency is widened, as far as possible in increase within reason
On the premise of volume and weight, the power output of whole test system is improved, and survey for the supporting impedance of the test equipment designs
Part is measured, becomes the earthing or grounding means broadband integrated test system of complete set.
To achieve these goals, the present invention adopts the following technical scheme that：
A kind of broadband test device for being used to measure grounding body impedance, it is characterised in that including based on simulation PI regulations
Driving source and controller based on DSP；
Driving source based on simulation PI regulations includes AC/DC converters, DC/AC converters, pi regulator, SPWM and compared
Device；The input of AC/DC converters is the input of the driving source based on simulation PI regulations；The output end of AC/DC converters connects
The input of DC/AC converters is connect, the output end of DC/AC converters is as the output end based on the driving source for simulating PI regulations；
The first input end of the output end connection comparator of DC/AC converters, the second of the output end connection comparator of given circuit are defeated
Enter end, the input of the output end connection pi regulator of comparator, the control of the output end connection AC/DC converters of pi regulator
End；
The output end of the input connection DC/AC converters of controller based on DSP, two of the controller based on DSP
Output end connects the input of given circuit and SPWM input respectively；The control of SPWM output end connection DC/AC converters
End processed.
Further, in the driving source based on simulation PI regulations, by the AC/DC converters that input by convert alternating current Cheng Zhi
Stream electricity provides busbar voltage for DC/AC converters, then converts generation frequency and the adjustable sine wave electricity of amplitude through DC/AC converters
Source；The Setting signal of driving source is produced by the controller based on DSP, with the output voltage signal of DC/AC converters compared with
It is compared in device, error signal is sent into simulation pi regulator, forms voltage control loop.
Further, AC/DC converters are both used as DC sources, again the prime as AC sources, and bus is provided for DC/AC converters
Voltage；Wherein, AC and DC output switching is completed using one group of switching switch；The output end of AC/DC converters is connected with first
Switch contact, the output end of DC/AC converters are connected with second switch contact；The of the fixing end connection comparator of switching switch
One input, switching the mobile terminal of switch can select to connect first switch contact or second switch contact, for switch AC and
DC output.
Further, the controller based on DSP, control D/A converter produces controllable driving source Setting signal, with DC/AC
The relatively rear caused error signal of converter output voltage feedback signal passes through the bus that pi regulator controls AC/DC parts to provide
Voltage；Meanwhile the controller based on DSP produces the SPWM synchronous modulations waveform control DC/AC converter output alternating currents of wideband
Frequency, the measurement of the voltage and current signal to impedance measurement point is completed together with peripheral sampled signal process circuit, and count
Calculate impedance value.
Further, in addition to the man-machine interactive system based on ARM；Man-machine interactive system connection based on ARM is based on DSP
Controller；Man-machine interactive system based on ARM, instructed for receiving user configuration by external key, pass through LCD display
Current measurement configuration condition and impedance measurements are shown, and by ARM and DSP communication port, realizes ARM to whole system
The monitoring of the state of system.
Further, AC/DC converters are connected with DC/AC converters two-layer configuration by LC buffer circuits.
Further, the output end of DC/AC converters sets selectable electric capacity C1 and C2, can by switching C1 and C2
The frequency range for making the driving source output alternating current based on simulation PI regulations is 20Hz~30kHz.
A kind of Broad-band Measurement Method for Electromagnetic for being used to measure grounding body impedance, including：Simulate the output of the driving source of PI regulations
End connects grounding body to be measured, there is provided driving voltage；Sample circuit is acquired and turned to voltage, the current signal at grounding body both ends
The voltage signal for changing 0-3V into gives AD processing inside the controller based on DSP, is then based on DSP controller to AD
Voltage, the digital quantity of electric current being converted to carry out computing, obtain the impedance value of grounding body.
Design requirement of the invention according to earthing or grounding means broadband integrated test system, it is determined that overall system design frame
Frame.Mainly include three parts：Driving source, the controller based on DSP and the man-machine interaction based on ARM based on simulation PI regulations
System.
The driving source main circuit of earthing or grounding means broadband integrated test system is divided into two-layer configuration, will by the AC/DC inputted
Convert alternating current provides busbar voltage into direct current for DC/AC parts, then adjustable just through DC/AC conversion generation frequency and amplitude
String ripple power supply.The Setting signal of driving source is produced by DSP, compared with output voltage signal, error signal is sent into mould
Intend pi regulator, form voltage control loop.
Wherein AC-DC converter is both used as DC sources, again the prime as AC sources, and busbar voltage is provided for DC-AC parts.Its
In, AC and DC output switching are completed using one group of switching switch.
Controller based on DSP, main function have：Control D/A converter to produce controllable driving source Setting signal, produce
The SPWM synchronous modulation waveforms of wideband, complete the voltage and current to impedance measurement point together with peripheral sampled signal process circuit
The measurement of signal, and computing impedance value, while be responsible for receiving the command signal that ARM is provided, realize that state is supervised to whole driving source
Control.
Man-machine interactive system based on ARM, it is mainly used in receiving user configuration instruction by external key, is shown by LCD
Show that device shows current measurement configuration condition and impedance measurements, and by ARM and DSP communication port, realize ARM to whole
The monitoring of the state of individual system.
Relative to prior art, the invention has the advantages that：
1st, on the basis for analyzing existing high frequency measurement system and inverter, the present invention proposes existing wideband
The structure of impedance measurement system with ground, its main power section use AC-DC and DC-AC two-layer configuration.
2nd, wideband output is the key component of the present invention, except being shifted onto switching frequency using high performance MOSFET
Outside 300kHz, mainly by what the mode of " SPWM+ resonance " was completed (two groups of filtering parameters of low frequency and high frequency are devised, are passed through
Switch filter capacitor to realize, low frequency filtering, high-frequency resonant).
3rd, isolation sampling, instrument amplification, precision rectifying and programmable-gain control have been used respectively during signal condition
Circuit processed carries out processing to signal and has reached precision required by system, and realizes automatically selecting for measuring range.
4th, the LCD interface circuit design methods and procedures frameworks of the man-machine interactive system based on ARM are given, and are realized
The flow of measurement and management.
Brief description of the drawings
Fig. 1 is a kind of structured flowchart for being used to measure the broadband test device of grounding body impedance of the present invention；
Fig. 2 is the system construction drawing of driving source；
Fig. 3 is output filter capacitor switching circuit schematic diagram；
Fig. 4 is the system block diagram of the controller based on DSP；
Fig. 5 is the hardware architecture diagram of man-machine interactive system.
Embodiment
Refer to shown in Fig. 1, a kind of broadband test device for being used to measure grounding body impedance of the present invention, including based on mould
Intend driving source, the controller (DSP widebands SPWM and signal processing system) based on DSP and the man-machine friendship based on ARM of PI regulations
Mutual system.
Driving source based on simulation PI regulations includes AC/DC converters, DC/AC converters, pi regulator, SPWM and compared
Device；The input of AC/DC converters is the input of the driving source based on simulation PI regulations；The output end of AC/DC converters connects
The input of DC/AC converters is connect, the output end of DC/AC converters is as the output end based on the driving source for simulating PI regulations；
The first input end of the output end connection comparator of DC/AC converters, the second of the output end connection comparator of given circuit are defeated
Enter end, the input of the output end connection pi regulator of comparator, the control of the output end connection AC/DC converters of pi regulator
End.The imitated output quantity of given circuit as reference voltage compared with the sampled value of output voltage, feed back by result of the comparison
To pi regulator so as to realizing the closed-loop control of output voltage.
The output end of the input connection DC/AC converters of controller based on DSP, two of the controller based on DSP
Output end connects the input of given circuit and SPWM input respectively；The control of SPWM output end connection DC/AC converters
End processed.
Controller of the man-machine interactive system connection based on DSP based on ARM.
Driving source main circuit based on simulation PI regulations is divided into two-layer configuration, by the AC/DC converters that input by alternating current
It is transformed into direct current and provides busbar voltage for DC/AC converters, then it is adjustable through DC/AC converters conversion generation frequency and amplitude
Sine-wave power.The given voltage signal of driving source is produced by the controller based on DSP, the output electricity with DC/AC converters
Pressure signal is compared in a comparator, and error signal is sent into simulation pi regulator, forms voltage control loop.
Wherein AC/DC converters are both used as DC sources, again the prime as AC sources, and busbar voltage is provided for DC/AC converters.
Wherein, AC and DC output switching completes (as shown in Figure 2) using one group of switching switch.The output end connection of AC/DC converters
There is first switch contact, the output end of DC/AC converters is connected with second switch contact；The fixing end connection of switching switch is compared
The first input end of device, switching the mobile terminal of switch can select to connect first switch contact or second switch contact, for cutting
Change AC and DC output.
Controller based on DSP, main function have：D/A converter is controlled to produce controllable driving source Setting signal, with DC/
The relatively rear caused error signal of AC converters output voltage feedback signal passes through the mother that pi regulator controls AC/DC parts to provide
Line voltage；Meanwhile the controller based on DSP produces the SPWM synchronous modulations waveform control DC/AC converter output exchanges of wideband
The frequency of electricity, completes the measurement of the voltage and current signal to impedance measurement point together with peripheral sampled signal process circuit, and
Computing impedance value, while be responsible for receiving the command signal that ARM is provided, condition monitoring is realized to whole driving source.Specifically surveyed
During examination, by pi regulator and SPWM closed-loop control, the output voltage and frequency of the driving source of monitoring simulation PI regulations are can
Setting value in the range of tune；The output end for the driving source for simulating PI regulations is connected into grounding body to be measured, there is provided driving voltage；Sampling
Circuit, which is acquired to voltage, the current signal at grounding body both ends and is converted into 0-3V voltage signal, gives the control based on DSP
AD processing inside device processed, it is then based on voltage, the digital quantity of electric current that DSP controller obtains to AD conversion and transports
Calculate, obtain the impedance value of grounding body.
Man-machine interactive system based on ARM, it is mainly used in receiving user configuration instruction by external key, is shown by LCD
Show that device shows current measurement configuration condition and impedance measurements, and by ARM and DSP communication port, realize ARM to whole
The monitoring of the state of individual system.
In present system, the controller based on DSP is the control core of whole system；Man-machine interaction system based on ARM
Reason human-computer interaction interface under the overall leadership, it is responsible for providing metrical information to DSP, and receives the measurement result of DSP returns.
The system architecture of driving source of the present invention is as shown in Fig. 2 by AC/DC converters and DC/AC converter two-layer configuration groups
Into being connected by LC buffer circuits, while system is possessed alternating current-direct current fan-out capability by the switching of output end switch.
Because the frequency band that the present invention exports is wider, the frequency range for exporting alternating current is 20Hz~30kHz, therefore the present invention
Devise two groups of filtering parameters：Selectable electric capacity C1 and C2 is set in the output end of DC/AC converters, by switching C1 and C2
The output waveform quality of wide frequency range can be ensured, the frequency range for making output alternating current is 20Hz~30kHz；As shown in Figure 3.
The system block diagram of the controller based on DSP is determined according to the design requirement of overall plan, as shown in Figure 4.Entirely
System is divided by its function as 5 bulks using DSP as controller.It is to be controlled by the waveform modulated part of EPWM controls, by SPI1 respectively
And it is sent into A/D and carries out the signal conditioning circuit of analog-to-digital conversion, electric capacity switching circuit and AC/DC logic controls electricity by GPIO controls
Road, the given circuit for the driving source being made up of the SPI2 D/A converters controlled and the communication interface with ARM by SCI controls.This
Invention has selected the TMS320F28035 of TI companies as master devices on the premise of system requirements are considered.
Man-machine interactive system hardware configuration is devised according to overall plan requirement, as shown in Figure 5.Wherein master controller is selected
ST ARM chip STM32F103, display device have selected 5.7 cun of OCM320240-3 liquid crystal displays of company of Jinpeng,
It can realize that ARM exchanges with LCD data command by FSMC (flexible static storage controller) interface, GPIO mouths are controlled
Indicator lamp be used to indicate the running status of system, button is used under different working conditions, realized to the defeated of user instruction
Enter, the communication with DSP is completed by the USART inside ARM.
Claims (8)
1. a kind of broadband test device for being used to measure grounding body impedance, it is characterised in that including based on simulation PI regulations
Driving source and the controller based on DSP；
Driving source based on simulation PI regulations includes AC/DC converters, DC/AC converters, pi regulator, SPWM and comparator；
The input of AC/DC converters is the input of the driving source based on simulation PI regulations；The output end connection of AC/DC converters
The input of DC/AC converters, the output end of DC/AC converters is as the output end based on the driving source for simulating PI regulations；DC/
The first input end of the output end connection comparator of AC converters, the second input of the output end connection comparator of given circuit
End, the input of the output end connection pi regulator of comparator, the control of the output end connection AC/DC converters of pi regulator
End；
The output end of the input connection DC/AC converters of controller based on DSP, two outputs of the controller based on DSP
End connects the input of given circuit and SPWM input respectively；The control terminal of SPWM output end connection DC/AC converters.
A kind of 2. broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that base
In the driving source of simulation PI regulations, convert alternating current is carried into direct current for DC/AC converters by the AC/DC converters inputted
Generation frequency and the adjustable sine-wave power of amplitude are converted for busbar voltage, then through DC/AC converters；Pass through the control based on DSP
Device processed produces the Setting signal of driving source, with the output voltage signals of DC/AC converters in a comparator compared with, by error
Signal is sent into simulation pi regulator, forms voltage control loop.
A kind of 3. broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that
AC/DC converters are both used as DC sources, again the prime as AC sources, and busbar voltage is provided for DC/AC converters；Wherein, AC and DC
Output switching completed using one group of switching switch；The output end of AC/DC converters is connected with first switch contact, and DC/AC becomes
The output end of parallel operation is connected with second switch contact；The first input end of the fixing end connection comparator of switching switch, switching are opened
The mobile terminal of pass can select to connect first switch contact or second switch contact, for switching AC and DC output.
A kind of 4. broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that base
In DSP controller, control D/A converter produces controllable driving source Setting signal, fed back with DC/AC converters output voltage
The relatively rear caused error signal of signal passes through the busbar voltage that pi regulator controls AC/DC parts to provide；Meanwhile based on DSP
Controller produce wideband SPWM synchronous modulations waveform control DC/AC converters output alternating current frequency, sampled with periphery
Signal processing circuit completes the measurement of the voltage and current signal to impedance measurement point, and computing impedance value together.
5. a kind of broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that also
Including the man-machine interactive system based on ARM；Controller of the man-machine interactive system connection based on DSP based on ARM；Based on ARM's
Man-machine interactive system, instructed for receiving user configuration by external key, show that current measurement configures by LCD display
Condition and impedance measurements, and by ARM and DSP communication port, realize monitoring of the ARM to the state of whole system.
A kind of 6. broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that
AC/DC converters are connected with DC/AC converters two-layer configuration by LC buffer circuits.
A kind of 7. broadband test device for being used to measure grounding body impedance according to claim 1, it is characterised in that
The output end of DC/AC converters sets selectable electric capacity C1 and C2, can be made based on simulation PI regulations by switching C1 and C2
Driving source output alternating current frequency range be 20Hz~30kHz.
8. a kind of Broad-band Measurement Method for Electromagnetic for being used to measure grounding body impedance, it is characterised in that based in claim 1 to 7
A kind of broadband test device for being used to measure grounding body impedance described in one, including：Simulate the defeated of the driving source of PI regulations
Go out end and connect grounding body to be measured, there is provided driving voltage；Sample circuit is acquired simultaneously to voltage, the current signal at grounding body both ends
The voltage signal for being converted into 0-3V gives AD processing inside the controller based on DSP, is then based on DSP controller pair
The digital quantity progress computing of voltage, electric current that AD conversion obtains, obtains the impedance value of grounding body.
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| CN201710979429.3A CN107765099B (en) | 2017-10-19 | 2017-10-19 | Broadband testing device and method for measuring impedance of grounding body |
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| CN201710979429.3A CN107765099B (en) | 2017-10-19 | 2017-10-19 | Broadband testing device and method for measuring impedance of grounding body |
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Cited By (2)
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| CN109283396A (en) * | 2018-10-29 | 2019-01-29 | 国网陕西省电力公司电力科学研究院 | Ground resistance measurement method and system, the pincers resistance instrument for quantifying noiseproof feature |
| CN109374977A (en) * | 2018-10-19 | 2019-02-22 | 中国人民解放军空军勤务学院 | A kind of quick detection device software of online resistance and the quick detection device of online resistance |
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