CN206321710U - A kind of frequency conversion electric current earth loop impedance test instrument - Google Patents
A kind of frequency conversion electric current earth loop impedance test instrument Download PDFInfo
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- CN206321710U CN206321710U CN201621315542.9U CN201621315542U CN206321710U CN 206321710 U CN206321710 U CN 206321710U CN 201621315542 U CN201621315542 U CN 201621315542U CN 206321710 U CN206321710 U CN 206321710U
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Abstract
The utility model discloses a kind of frequency conversion electric current earth loop impedance test instrument, it is adaptable to tests power-frequency earthing impedance and the soil resistivity of all kinds of earthing or grounding means.The utility model is mainly made up of frequency conversion main circuit, control system, systems soft ware, including an input circuit, a current rectifying and wave filtering circuit, an inverter circuit (containing drive circuit and buffer circuit), an output filter circuit, an output control circuit, a pwm signal generation circuit, a signal acquisition circuit and an input/output control circuit.The utility model employs Novel variable-frequency AC power, pass through the measures such as microcomputer control and signal transacting, the anti-interference problem in test process is solved well, simplify test operation process, the precision and accuracy of test result are improved, labor intensity and the experimentation cost of testing crew is greatly reduced.
Description
【Technical field】
The utility model belongs to testing impedance technical field, is related to a kind of frequency conversion electric current earth loop impedance test instrument.
【Background technology】
With the raising of system nominal voltage class, high voltage, Large Copacity electric substation it is increasing, occur in that many big
Type, the grounded screen of ultra-large type.The working condition of grounded screen is directly connected to the safety of personal safety, power equipment and power system
Operation.Scientifically and rationally test the various characterisitic parameters of grounded screen, the safe condition of accurate evaluation grounded screen, to ensuring power train
The safe and reliable operation of system and the personal safety tool of work of transformer substation personnel are of great significance.
The limitation of tested equipment technical merit before, the test for grounded screen is often limited only to measurement of Grounding Resistance
Size.Essentially for large ground network, " earth resistance " shows significantly " complex impedance " property, i.e., comprising resistance point
Amount, reactive component, so " earth resistance " should be replaced using the concept of " impedance ground ".
The multi-functional mesh grounding characteristic measuring system of frequency conversion high current to grounded screen by injecting an electricity different from power frequency
Stream, efficiently avoid measurement error caused by 50Hz and other interference signals, measurement grounded screen that can accurately, economic, safe
Impedance ground, contact voltage, step voltage, the parameter such as place surface potential gradient, while so that measurement process become it is convenient and
Safety.
【Utility model content】
The purpose of this utility model is that the shortcoming for overcoming above-mentioned prior art is surveyed there is provided a kind of frequency conversion electric current impedance ground
Try instrument.
To reach above-mentioned purpose, the utility model is achieved using following technical scheme：
A kind of frequency conversion electric current earth loop impedance test instrument, including the power cabinet and controller being connected by 3 cables；Power cabinet is used
In output frequency conversion sinusoidal voltage, output voltage range be 0~300V, output frequency be 35Hz~65Hz, 0~30A of output current,
Front panel is provided with the voltmeter and ammeter of the voltage and current value for measurement of Grounding Resistance；Controller is used to control power supply
Cabinet exports frequency conversion sinusoidal voltage, including frequency conversion main circuit and control system, and frequency conversion main circuit includes input circuit, rectifying and wave-filtering electricity
Road, the inverter circuit containing drive circuit and buffer circuit, output filter circuit and output control circuit；Control system includes single
Piece machine, pwm signal generation circuit, signal acquisition circuit, input/output control circuit and power module；Signal acquisition circuit is used
In collection terminal voltage signal, load current signal, induced voltage signal and induced-current.
The utility model is further improved：
Input circuit includes protective breaker Q1, input contactor JC1 and soft start resistance R1；Protective breaker Q1 is used for
Protection is provided when mains input side is short-circuit；After main power source is connected, after 220V industrial-frequency alternating currents are given by soft start resistance R1
Continuous filter capacitor charging；After soft start terminates, the relay J2 control input contactor JC1 works that relay board is passed through by single-chip microcomputer
Make, main contact is closed after the JC1 work of input contactor, soft start resistance R1 is cut off, input circuit enters working condition.
Current rectifying and wave filtering circuit includes diode rectifier bridge and filter condenser group C1.
Inverter circuit uses voltage source inverter, and inverter bridge main circuit is by two half-bridge insulated gate bipolar transistor IGBT
Composition.
Output filter circuit includes output transformer and ac filter capacitor bank C2, the leakage inductance and ac filter of transformer
Capacitor bank C2 composition output LC wave filters；Output control circuit includes circuit breaker Q 2, output contactor JC2 and output contact
Device；Circuit breaker Q 2 is used to protection is overloaded or provided when short-circuit in power output end, and output contactor is used to connect output extremely load；
When needing power supply to export, the relay J3 work on Single-chip Controlling relay board, its normally opened contact connects output contactor
JC2 wire loop, output contactor JC2 work, main contact closure, power supply output.
Single-chip microcomputer uses AVR128 single-chip microcomputers, and man-machine interaction is shown using free-standing key and VFD；Pwm signal generation circuit
Pwm signal is generated using integrated chip 8382, is connected by system bus with single-chip microcomputer.
Compared with prior art, the utility model has the advantages that：
The utility model uses Novel variable-frequency AC power, by measures such as microcomputer control and signal transactings, solves well
The anti-interference problem determined in test process, simplifies test operation process, improves the precision and accuracy of test result, greatly
Big labor intensity and the experimentation cost for reducing testing crew.The power frequency that the utility model is applied to test all kinds of earthing or grounding means connects
Ground impedance and soil resistivity.Using alien frequencies Anti-Jamming Technique, it can accurately be measured under strong interference environment under power frequency 50Hz
Data.
【Brief description of the drawings】
Fig. 1 is the structural representation of the utility model controller front panel；
Fig. 2 is the utility model frequency conversion main circuit diagram；
Fig. 3 is the utility model inverter and electric operation control circuit figure；
Fig. 4 is the structural representation of utility model works power module；
Fig. 5 is the utility model instrument and contactor control circuit figure；
Fig. 6-1 is the structural representation of the utility model relay circuit plate；
Fig. 6-2 is the structural representation of the utility model I/O interface cables；
Fig. 7 is the utility model single-chip microcomputer fundamental system figure；
Fig. 8-1 is the circuit theory diagrams of the utility model 8382；
Fig. 8-2 is the crystal oscillating circuit figure of the utility model 8382；
Fig. 9-1 is the utility model voltage collection circuit figure；
Fig. 9-2 is the utility model current collection circuit figure；
Figure 10-1 is that the utility model inputs control principle circuit diagram；
Figure 10-2 is that the utility model inputs control principle circuit diagram.
【Embodiment】
The utility model is described in further detail below in conjunction with the accompanying drawings：
Referring to Fig. 1, the utility model is controlled and signal transacting and the ground connection for using Novel variable-frequency AC power based on microcomputer
Impedance instrument, is made up of power cabinet and controller, and both are connected by 3 cables.Power cabinet is used to export frequency conversion sinusoidal voltage,
Output voltage range is 0~300V, and output frequency is 35Hz~65Hz, and 0~30A of output current, front panel is provided with voltmeter
And ammeter, the associated voltage of measurable earth resistance, current value.Controller is used to control power cabinet to export the sinusoidal electricity of frequency conversion
Pressure, its power switch is in plate below, and front panel has setting, increases, reduces, determining, cancelling, switching on and off seven buttons.Connect
Ground impedance instrument includes a frequency conversion main circuit and a control system.Frequency conversion main circuit include input circuit, one
Current rectifying and wave filtering circuit, inverter circuit (containing drive circuit and buffer circuit), an output filter circuit.Control system includes
One pwm signal generation circuit, a signal acquisition circuit and an input/output control circuit.
Frequency conversion main circuit theory diagram is as shown in Fig. 2 using device for high-power power electronic IGBT, by AVR single chip control
System.Including an input circuit, current rectifying and wave filtering circuit, inverter circuit (containing drive circuit and buffer circuit), one
Output filter circuit.
Input circuit includes protective breaker Q1, input contactor JC1 and soft start resistance R1.Protective breaker Q1 is in electricity
Source input side provides protection when short-circuit.After main power source is connected, 220V industrial-frequency alternating currents are by soft start resistance R1 to follow-up filter
Ripple electric capacity is charged, it is to avoid larger rush of current is caused to the electrolytic capacitor in current rectifying and wave filtering circuit.After soft start terminates, by
Single-chip microcomputer is worked (see Fig. 5) by relay J2 (see Fig. 6) the control input contactor JC1 of relay board, inputs contactor JC1
Main contact is closed after work, and soft start resistance R1 is cut off, and input circuit enters normal operating conditions.
The AC power frequency voltage transformation of input is HVDC by current rectifying and wave filtering circuit, and carries out smothing filtering and accumulation of energy,
Condition is provided for inverter circuit work.The circuit is mainly made up of heavy-duty diode rectifier bridge and filter condenser group C1.
Inverter circuit (inverter) is the core component of variable-frequency power sources, and HVDC is transformed to the exchange arteries and veins of high frequency
Voltage is rushed, and carries out ac buck.Inverter circuit is voltage source inverter, and inverter bridge main circuit is by two half-bridge insulated gate bipolars
Property transistor IGBT composition, using conventional bridge inverter main circuit, realize that DC-AC is converted.Control system controls cable by PWM
Send after the receiver board receiving in control signal, power-supply system, then IGBT module is applied to by driving plate, complete DC/AC and become
Change, as shown in Figure 3.Meanwhile, buffer circuit plate is further connected with IGBT.15V-1 and 15V-2 is driving plate working power, by work
Make power module to provide (as shown in Figure 4).
Inversion output summation current transformer secondary detects the output of inverter, powering order for control system in Fig. 4
Control relay J1 contact is used to control detecting and controlling system and the powering order of power-supply system (J1 coils are as shown in Figure 5).
Only after power-supply system power-up, Fig. 5 repeat circuit J1 coils obtain electric work, its closing of contact (see Fig. 4), pass through
2L1,2L2 could work the power in detecting and controlling system, detecting and controlling system, it is ensured that the realization of soft start function and
The reliably working of power-supply system.Two pieces of instrument in Fig. 5 are respectively full range voltmeter and ammeter, and the input range of voltmeter is
0~500V, the supporting current transformer ratio of ammeter is 30A/30mA.Contactor JC1, JC2 are respectively input, output contact
Whether device, its work passes through relay board control by single-chip microcomputer (relay board is as shown in Figure 6).T-P is TEMP in Fig. 6
Device, the overtemperature protection for variable-frequency power sources.
Output filter circuit is main to be made up of (see as shown in Figure 2) output transformer and ac filter capacitor bank C2.Adopt
There is transformation and buffer action with output transformer, inversion link and load isolation are opened, reduce load acute variation to inversion
The impact influence of link；Meanwhile, leakage inductance and ac filter capacitor bank C2 the composition output LC wave filters of transformer, for suppressing
Harmonic components in voltage waveform so that be output as sine wave alternating current.
Output control circuit is made up of circuit breaker Q 2 and output contactor JC2.Circuit breaker Q 2 is used in power output end mistake
Carry or provide protection when short-circuit；Output contactor K3 is used to connect output to load.When needing power supply to export, Single-chip Controlling
Relay J3 work on relay board, its normally opened contact connects output contactor JC2 wire loop, output contactor JC2
Work, main contact closure, power supply output.
Control system constitutes microcontroller fundamental system, as shown in Figure 7 using AVR128 single-chip microcomputers as core.Man-machine interaction
Shown using free-standing key and VFD.Control system includes a pwm signal generation circuit, a signal acquisition circuit and one
Input/output control circuit.Pwm signal generation circuit generates pwm signal using integrated chip 8382, and the connection with single-chip microcomputer is
System bus structure, as shown in Figure 8.Signal acquisition circuit collection terminal voltage signal, load current signal, induced voltage signal with
And induced-current, as shown in Figure 9.Input/output control circuit is mainly soft start control, using string resistance method, utilizes relay
Switch over control.Output, which is connected, uses Control contactor.Light-coupled isolation interference methods are employed, such as Figure 10 institutes
Show.
The utility model provides a kind of frequency conversion current impedance tester, it is adaptable to test the power-frequency earthing of all kinds of earthing or grounding means
Impedance and soil resistivity.Using alien frequencies Anti-Jamming Technique, the number under power frequency 50Hz can be accurately measured under strong interference environment
According to.Frequency conversion electric current earth loop impedance test instrument is made up of power cabinet and controller, and both are by cable connection.Power cabinet, which is used to export, to be become
Frequency sinusoidal voltage, output voltage range is 0~300V, and output frequency is 35Hz~65Hz, 0~30A of output current, front panel peace
Equipped with voltmeter and ammeter, the associated voltage of measurable earth resistance, current value.Controller is used to control power cabinet output change
Frequency sinusoidal voltage, its power switch is in plate below, and front panel has setting, increases, reduces, determining, cancelling, switching on and off seven
Button, controller front panel is as shown in Figure 1.
" setting " key is used to set：Initial output voltage and frequency, online output voltage；
" increase " key is used to increase voltage and the numerical value of frequency；
" reduction " key is used to reduce voltage and the numerical value of frequency；
" it is determined that " magnitude of voltage and frequency values of the key for confirming setting；
" cancellation " key is used to cancel invalid setting magnitude of voltage and frequency values；
" on " key is used to connect output relay contact；
"off" key is used for the contact for disconnecting output relay.
The course of work of the present utility model：
" power supply " switch is connected (in plate below), into soft start interface, countdown in 10 seconds.
After countdown terminates, connect input relay (sound of relay adhesive can be heard, " and " a sound).Automatically
Into parameter monitoring interface.
On parameter monitoring interface after soft start, " setting " key is pressed, parameter setting first can be carried out, left arrow refers to
To voltage, voltage can be configured, single presses " increase " key, magnitude of voltage can add 1V on the basis of default value, press
" increase " key is not put, and magnitude of voltage can be increased continuously according to 1V stepping, untill increasing to 300V always；Single is pressed " reduction "
Key, the numerical value of voltage can reduce 1V, and long-press " reduction " key, magnitude of voltage continuously declines according to 1V stepping, until untill 0V.
It is adjusted to after suitable numerical value, press " it is determined that " key, obtained in magnitude of voltage and a check mark " √ " occurs below, simultaneously
Left arrow points to a line of frequency values, represents：Setting completed for magnitude of voltage, will set the numerical value of frequency, presses and " increases
Plus " and " reduction " key, the predetermined value that frequency values can be adjusted, operating method is ibid.
Frequency values after setting completed, press " confirmation " key, obtained in frequency values and a check mark " √ " also occurs below, together
When, " setting successfully occurs in fourth line！" signal language, the numerical value of account for voltage and frequency has been arranged to work(.
If during parameter setting, the numerical value of setting were unsatisfied with, or other reasons would be wanted to cancel the ginseng set
Number, can press " cancellation " key, system will be run according to the parameter before setting before " on " key is pressed.
" set successfully！" after, " on " key is pressed, parameter monitoring interface is switched to, by the voltage of assigned frequency according to journey
The magnitude of voltage specified of the step-length of control from the slow liters of 0V.Slow to be raised to after predetermined numerical value, connecting output relay (can hear relay
The sound of device adhesive, and " " a sound), the magnitude of voltage of output is now automatically adjusted according to PID control program to the numerical value specified,
Current value timely can be updated onto interface simultaneously.
The frequency for setting output is 48Hz, and setting voltage swing is 100V.
On the basis of stable output, the size of output voltage can be changed at any time, noted：Now frequency can not be changed.
Press " setting " key, it may appear that interface is set online.The application method of " increase ", " reduction " is ibid.After setting completed, press
" confirmation " key, appearance sets successfully interface, continues after 1.5 seconds, the parameter monitoring interface of automatic switchover, and according to new settings
Numerical value, inside carry out PID control adjust output voltage size, when one section after, output voltage can be stabilized to new setting again
Magnitude of voltage on, stablize again on 200V magnitude of voltage.
After being completed, "off" key is pressed, output voltage will be dropped to after 0V according to program control step-length is slow, output relay
Disconnect and (sound that relay disconnects can be heard).
If carrying out the output of next round, " setting " key can be pressed again, the voltage and frequency of output is reset, note
Meaning, now frequency can be reset.
Above content is only explanation technological thought of the present utility model, it is impossible to limit protection model of the present utility model with this
Enclose, it is every according to the utility model proposes technological thought, any change done on the basis of technical scheme each falls within this reality
Within protection domain with new claims.
Claims (6)
1. a kind of frequency conversion electric current earth loop impedance test instrument, it is characterised in that including the power cabinet being connected by 3 cables and control
Instrument；Power cabinet is used to export frequency conversion sinusoidal voltage, and output voltage range is 0~300V, and output frequency is 35Hz~65Hz, output
0~30A of electric current, front panel is provided with the voltmeter and ammeter of the voltage and current value for measurement of Grounding Resistance；Controller
For controlling power cabinet to export frequency conversion sinusoidal voltage, including frequency conversion main circuit and control system, frequency conversion main circuit includes input electricity
Road, current rectifying and wave filtering circuit, the inverter circuit containing drive circuit and buffer circuit, output filter circuit and output control circuit；
Control system includes single-chip microcomputer, pwm signal generation circuit, signal acquisition circuit, input/output control circuit and power module；
Signal acquisition circuit is used to gather terminal voltage signal, load current signal, induced voltage signal and induced-current.
2. frequency conversion electric current earth loop impedance test instrument according to claim 1, it is characterised in that it is disconnected that input circuit includes protection
Road device Q1, input contactor JC1 and soft start resistance R1；Protective breaker Q1 is used to provide guarantor when mains input side is short-circuit
Shield；After main power source is connected, 220V industrial-frequency alternating currents are charged by soft start resistance R1 to follow-up filter capacitor；Soft start terminates
Afterwards, worked by single-chip microcomputer by the relay J2 control input contactors JC1 of relay board, it is main after the JC1 work of input contactor
Contact closure, soft start resistance R1 is cut off, and input circuit enters working condition.
3. frequency conversion electric current earth loop impedance test instrument according to claim 1, it is characterised in that current rectifying and wave filtering circuit includes two
Pole pipe rectifier bridge and filter condenser group C1.
4. frequency conversion electric current earth loop impedance test instrument according to claim 1, it is characterised in that inverter circuit uses voltage-type
Inverter, inverter bridge main circuit is made up of two half-bridge insulated gate bipolar transistor IGBT.
5. frequency conversion electric current earth loop impedance test instrument according to claim 1, it is characterised in that output filter circuit includes defeated
Go out transformer and ac filter capacitor bank C2, leakage inductance and ac filter capacitor bank C2 the composition output LC filtering of transformer
Device；Output control circuit includes circuit breaker Q 2, output contactor JC2 and output contactor；Circuit breaker Q 2 is used for defeated in power supply
Go out end overload or protection is provided when short-circuit, output contactor is used to connect output to load；When needing power supply to export, single-chip microcomputer
Relay J3 work on control relay plate, its normally opened contact connects output contactor JC2 wire loop, output contactor
JC2 works, main contact closure, power supply output.
6. frequency conversion electric current earth loop impedance test instrument according to claim 1, it is characterised in that single-chip microcomputer is mono- using AVR128
Piece machine, man-machine interaction is shown using free-standing key and VFD；Pwm signal generation circuit is using the generation PWM letters of integrated chip 8382
Number, it is connected by system bus with single-chip microcomputer.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201621315542.9U CN206321710U (en) | 2016-12-02 | 2016-12-02 | A kind of frequency conversion electric current earth loop impedance test instrument |
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| CN201621315542.9U CN206321710U (en) | 2016-12-02 | 2016-12-02 | A kind of frequency conversion electric current earth loop impedance test instrument |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107102207A (en) * | 2016-12-02 | 2017-08-29 | 国家电网公司 | A kind of earth loop impedance test instrument controlled based on microcomputer with signal transacting |
| CN107576847A (en) * | 2017-09-07 | 2018-01-12 | 西南交通大学 | A kind of vehicular tractive power supply system impedance frequency characteristic measurement apparatus and its measuring method |
| CN108919002A (en) * | 2018-07-05 | 2018-11-30 | 深圳市车电网络有限公司 | A kind of test macro of direct-current charging post |
| CN110850177A (en) * | 2019-12-20 | 2020-02-28 | 成都奥力斯电子科技有限公司 | High-frequency pulse digital ground resistance tester |
-
2016
- 2016-12-02 CN CN201621315542.9U patent/CN206321710U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107102207A (en) * | 2016-12-02 | 2017-08-29 | 国家电网公司 | A kind of earth loop impedance test instrument controlled based on microcomputer with signal transacting |
| CN107576847A (en) * | 2017-09-07 | 2018-01-12 | 西南交通大学 | A kind of vehicular tractive power supply system impedance frequency characteristic measurement apparatus and its measuring method |
| CN107576847B (en) * | 2017-09-07 | 2024-04-26 | 西南交通大学 | Impedance frequency characteristic measuring device and measuring method for vehicle-mounted traction power supply system |
| CN108919002A (en) * | 2018-07-05 | 2018-11-30 | 深圳市车电网络有限公司 | A kind of test macro of direct-current charging post |
| CN110850177A (en) * | 2019-12-20 | 2020-02-28 | 成都奥力斯电子科技有限公司 | High-frequency pulse digital ground resistance tester |
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