CN109459617A - The ground loop resistance measurement method of power test grounding intelligent prior-warning device - Google Patents
The ground loop resistance measurement method of power test grounding intelligent prior-warning device Download PDFInfo
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- CN109459617A CN109459617A CN201810012016.2A CN201810012016A CN109459617A CN 109459617 A CN109459617 A CN 109459617A CN 201810012016 A CN201810012016 A CN 201810012016A CN 109459617 A CN109459617 A CN 109459617A
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- resistance
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- voltage signal
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- grounding
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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
- G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
- G01R27/18—Measuring resistance to earth, i.e. line to ground
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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
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
本发明公开了一种电力试验接地智能预警装置的接地回路电阻测量方法，接地电阻测量模块包括恒流源测量单元和恒压源测量单元，恒流源测量单元包括恒流源、电压测量子单元和模数转换器，数模转换器将电压信号通过内部五个通道分别进行差异化放大后进行AD转换；恒压源检测单元作为容余测量，包括恒压源和霍尔传感器，与恒流源测量单元交替工作。本发明的实质性效果是：对数模转换器的增益通道进行设置，使得阈值周围的接地回路电阻测量更加精准，同时降低了远离阈值的接地电阻的电阻测量精度，提高了转换器整体测量效率，并增加了恒压源测量单元，从而提高了电力试验中接地保护的可靠性。
The invention discloses a grounding loop resistance measurement method of an electric power test grounding intelligent early warning device. A grounding resistance measurement module includes a constant current source measurement unit and a constant voltage source measurement unit, and the constant current source measurement unit includes a constant current source and a voltage measurement subunit. And the analog-to-digital converter, the digital-to-analog converter amplifies the voltage signal through the five internal channels and then performs AD conversion; the constant voltage source detection unit is used as a residual measurement, including a constant voltage source and a Hall sensor, and constant current The source-measure units work alternately. The substantial effect of the present invention is: setting the gain channel of the digital-to-analog converter makes the measurement of the ground loop resistance around the threshold more accurate, reduces the resistance measurement accuracy of the ground resistance far from the threshold, and improves the overall measurement efficiency of the converter , and increased the constant voltage source measurement unit, thereby improving the reliability of the grounding protection in the power test.
Description
Technical field
The present invention relates to technical field of electric power more particularly to a kind of earth-return circuits of power test grounding intelligent prior-warning device
Resistance measurement method.
Background technique
During electric power overhaul test, reliable test ground connection is that experimental data is accurate and the necessary of life equipment safety protects
Card.Substation will periodically carry out the high-potting of pressure resistance or shelf depreciation to power equipments such as transformer, mutual inductor, cables,
The all necessary reliable ground of all appts equipment of test, to guarantee personal safety.Existing power test ground connection prior-warning device is equal
Judge whether ground connection is qualified by the way that whether measurement ground loop resistance exceeds threshold value setting, so measurement ground loop resistance
Accuracy and measuring speed become the key problem of the prior-warning device.
103207342 B of Chinese patent Authorization Notice No. CN authorized announcement date on 09 07th, 2016, discloses one kind
Checking experiment grounding intelligent prior-warning device, it specifically includes that cpu controller, ground resistance measurement circuit, control loop, voice
Alarm system, LCD display and keypad, the cpu controller connection one are connect with direct current constant current output, ground connection and auxiliary
The DC va method ground resistance that place differential voltage measuring circuit is constituted measures circuit, is touched by cpu controller Interruption
Hair carries out resistance Timing measurement；The cpu controller is connected with a control loop output, it uses cpu controller I/O
Mouthful, by the relay and contactor that connect Control experiment on/off；The cpu controller is controlled configured with one with CPU
The keyboard that the connection of device interface, realization relevant operation and resistance definite value processed are arranged；It is able to achieve definite value can set, ground resistance it is real-time
Measure display, experiment power supply real-time control etc..But in above-mentioned patent use ground resistance measurement circuit on design one with
DC va method resistance measurement between 0.5A direct current constant current output, ground connection and auxiliary earth point based on differential voltage measuring circuit
Module carrys out measurement of Grounding Resistance, which makes analog-digital converter AD7705 not obtain abundant benefit
With, so that the reduction of ground loop resistance accuracy of measurement, and reduce measurement efficiency.
Summary of the invention
The technical problem to be solved by the present invention is to how design a kind of accuracy of measurement and survey for improving measurement loop resistance
The method of amount efficiency.
Used technical solution is the present invention in order to solve the above problem: a kind of power test grounding intelligent prior-warning device
Ground loop resistance measurement method, the input power of the power test grounding intelligent prior-warning device successively pass through power inlet,
Out-put supply plug-in strip and earth leakage circuit breaker be connected to power output for power test relevant apparatus power supply, input power according to
Secondary process power inlet and auxiliary supply transformer are processor module power supply, ground resistance measurement module, relay output
Module, voice cue module, display module, control button and debugging interface are connect with processor module, when ground resistance is examined
When the grounding resistance that survey module measures is greater than given threshold, processor module is by control relay output module come so that leakage
Electric protection breaker disconnect power supply output, which is characterized in that the ground resistance measurement module include constant-current source measuring unit and
Constant pressure source measuring unit, the constant-current source measuring unit include constant-current source, voltage measurement subelement and analog-digital converter AD7705,
The constant-current source accesses earth-return circuit, and the voltage measurement subelement is for measuring earth-return circuit both end voltage and by voltage signal
It is transmitted in digital analog converter AD7705, the digital analog converter AD7705 puts voltage signal by internal programmable-gain
Big device is AD converted after carrying out signal amplification；The constant pressure source detection unit includes constant pressure source and Hall sensor, the perseverance
Potential source accesses earth-return circuit, and the Hall sensor is located in earth-return circuit and current signal collected is transmitted to processor
Module.
Preferably, the Hall sensor is magnetic balancing current sensor, the response time is less than 10 μ s.
Preferably, set the threshold resistance B of ground resistance as 0.2 Ω, the setting side of the digital analog converter AD7705
Method is as follows:
S1: digital analog converter AD7705 is divided into 5 gain amplification channels, the first gain channel is used for 0 ~ 0.15 Ω resistance value model
The voltage signal amplification enclosed, voltage signal of second gain channel for 0.15 ~ 0.25 Ω Standard resistance range amplify, and third gain is logical
Voltage signal of the road for 0.25 ~ 2 Ω Standard resistance range amplifies, and the 4th gain channel is used for the voltage signal of 2 ~ 5 Ω Standard resistance ranges
Amplification, voltage signal of the 5th gain channel for 5 Ω or more resistance values amplify；
S2: wherein the Standard resistance range of the second gain channel service is (0.5B, 1.5B), and the gain channel is in setting gain factor
When, so that voltage signal is amplified to the full scale voltage close to analog-digital converter, so that the resistance value measurement of the Standard resistance range is the most
Precisely；
S3: 80% will be amplified to the voltage signal of adjacent first gain channel of the second gain channel and third gain channel
The size of digital analog converter full scale voltage；
S4: the voltage signal of the 4th gain channel is amplified to the size of 60% digital analog converter full scale voltage；
S5: the voltage signal of the 5th gain channel is amplified to the size of 50% digital analog converter full scale voltage.
Preferably, the constant-current source measuring unit and the constant pressure source measuring unit are in each measurement of Grounding Resistance week
It is worked alternatively in phase.
Preferably, the duty cycle of ground resistance measurement module is set as 80ms, wherein constant-current source measures cell operation
60ms, constant pressure source measuring unit work 20ms, constant pressure source increase the stability of measurement of Grounding Resistance as additional survey mode.
Substantial effect of the invention is: the gain channel of logarithm mode converter AD7705 is configured, so that threshold value is all
The ground loop resistance measurement enclosed is more accurate, while reducing the resistance measurement precision of the ground resistance far from threshold value, improves
Converter entirety measurement efficiency, and increase constant pressure source measuring unit, so that improve ground protection in power test can
By property.
Detailed description of the invention
Fig. 1 is the principle schematic diagram of power test grounding intelligent prior-warning device.
In figure: 1, processor module, 2, ground resistance measurement module, 3, relay output module, 4, voice cue module,
5, display module, 6, control button, 7, debugging interface, 8, out-put supply plug-in strip, 9, auxiliary supply transformer, 10, earth leakage protective
Breaker, 11, power output, 12, power inlet.
Specific embodiment
Below by specific embodiment, and in conjunction with attached drawing, a specific embodiment of the invention is further described in detail.
Fig. 1 is the principle schematic diagram of power test grounding intelligent prior-warning device, the power test grounding intelligent early warning
The input power of device successively passes through power inlet 12, out-put supply plug-in strip 8 and earth leakage circuit breaker 10 and is connected to power supply
Delivery outlet 11 is the power supply of power test relevant apparatus, and input power successively passes through power inlet 12 and auxiliary supply transformer 9
For processor module 1 power supply, ground resistance measurement module 2, relay output module 3, voice cue module 4, display module 5,
Control button 6 and debugging interface 7 are connect with processor module 1, when the grounding resistance that insulating resistance measuring module measures is big
When given threshold, processor module 1 is by control relay output module 3 come so that earth leakage circuit breaker 10 disconnects power supply
Output, ground resistance measurement module 2 include constant-current source measuring unit and constant pressure source measuring unit, and constant-current source measuring unit includes perseverance
Stream source, voltage measurement subelement and analog-digital converter AD7705, constant-current source access earth-return circuit, and voltage measurement subelement is for surveying
Voltage signal is simultaneously transmitted in digital analog converter AD7705 by amount earth-return circuit both end voltage, and digital analog converter AD7705 is by voltage
Signal is AD converted after carrying out signal amplification by internal programmable gain amplifier；Constant pressure source detection unit includes constant pressure
Source and Hall sensor, constant pressure source access earth-return circuit, and Hall sensor is located in earth-return circuit and believes electric current collected
Number it is transmitted to processor module 1.Constant-current source measuring unit and constant pressure source measuring unit are within each measurement of Grounding Resistance period
It works alternatively, wherein constant pressure source measuring unit is as capacity resistance measurement, when constant-current source measuring unit is measured and made mistakes to processing
Device module 1 transmits resistivity measurements, is cut off the power output when ground resistance is more than threshold value by earth leakage circuit breaker 10,
Guarantee electric power experimenter safety.Wherein, the duty cycle of ground resistance measurement module 2 is set as 80ms, and wherein constant-current source measures
Cell operation 60ms, constant pressure source measuring unit work 20ms, constant pressure source increase measurement of Grounding Resistance as additional survey mode
Stability.
The setting of ground resistance threshold value is less than 0.5 Ω under normal circumstances, and is carried out according to the temperature and humidity in power test area
Adjustment.Under normal conditions, the threshold resistance B of ground resistance is set as 0.2 Ω, and the setting method of digital analog converter AD7705 is such as
Under:
S1: digital analog converter AD7705 is divided into 5 gain amplification channels, the first gain channel is used for 0 ~ 0.15 Ω resistance value model
The voltage signal amplification enclosed, voltage signal of second gain channel for 0.15 ~ 0.25 Ω Standard resistance range amplify, and third gain is logical
Voltage signal of the road for 0.25 ~ 2 Ω Standard resistance range amplifies, and the 4th gain channel is used for the voltage signal of 2 ~ 5 Ω Standard resistance ranges
Amplification, voltage signal of the 5th gain channel for 5 Ω or more resistance values amplify；
S2: wherein the Standard resistance range of the second gain channel service is (0.5B, 1.5B), and the gain channel is in setting gain factor
When, so that voltage signal is amplified to the full scale voltage close to analog-digital converter, so that the resistance value measurement of the Standard resistance range is the most
Precisely；
S3: 80% will be amplified to the voltage signal of adjacent first gain channel of the second gain channel and third gain channel
The size of digital analog converter full scale voltage；
S4: the voltage signal of the 4th gain channel is amplified to the size of 60% digital analog converter full scale voltage；
S5: the voltage signal of the 5th gain channel is amplified to the size of 50% digital analog converter full scale voltage.
The voltage signal of second gain channel is amplified to the full scale voltage close to analog-digital converter, so that the resistance value model
The resistance value measurement enclosed is the most accurate, while other gain channels are accordingly reduced measurement accuracy, improves digital analog converter
The measurement efficiency of AD7705 can more rapidly cut off the power when imperfect earth, improve the power test grounding intelligent
The safety of prior-warning device.
Above-mentioned embodiment is only a preferred solution of the present invention, not the present invention is made in any form
Limitation, there are also other variations and modifications on the premise of not exceeding the technical scheme recorded in the claims.
Claims (5)
1. a kind of ground loop resistance measurement method of power test grounding intelligent prior-warning device, the power test grounding intelligent are pre-
The input power of alarm device successively passes through power inlet, out-put supply plug-in strip and earth leakage circuit breaker and is connected to power supply output
Mouth is that power test relevant apparatus is powered, and input power successively passes through power inlet and auxiliary supply transformer is processor die
Block power supply, ground resistance measurement module, relay output module, voice cue module, display module, control button and debugging connect
Mouth is connect with processor module, when the grounding resistance that insulating resistance measuring module measures is greater than given threshold, processor
Module is by control relay output module come so that earth leakage circuit breaker disconnects power supply output, which is characterized in that described to connect
Ground resistance measurement module includes constant-current source measuring unit and constant pressure source measuring unit,
The constant-current source measuring unit includes constant-current source, voltage measurement subelement and analog-digital converter AD7705, the constant-current source
Earth-return circuit is accessed, the voltage measurement subelement is for measuring earth-return circuit both end voltage and voltage signal being transmitted to digital-to-analogue
In converter AD7705, voltage signal is carried out letter by internal programmable gain amplifier by the digital analog converter AD7705
Number amplification after be AD converted；
The constant pressure source detection unit includes constant pressure source and Hall sensor, and the constant pressure source accesses earth-return circuit, the Hall
Sensor is located in earth-return circuit and current signal collected is transmitted to processor module.
2. the ground loop resistance measurement method of power test grounding intelligent prior-warning device according to claim 1, special
Sign is that the Hall sensor is magnetic balancing current sensor, and the response time is less than 10 μ s.
3. the ground loop resistance measurement method of power test grounding intelligent prior-warning device according to claim 1, special
Sign is, sets the threshold resistance B of ground resistance as 0.2 Ω, the setting method of the digital analog converter AD7705 is as follows:
S1: digital analog converter AD7705 is divided into 5 gain amplification channels, the first gain channel is used for 0 ~ 0.15 Ω resistance value model
The voltage signal amplification enclosed, voltage signal of second gain channel for 0.15 ~ 0.25 Ω Standard resistance range amplify, and third gain is logical
Voltage signal of the road for 0.25 ~ 2 Ω Standard resistance range amplifies, and the 4th gain channel is used for the voltage signal of 2 ~ 5 Ω Standard resistance ranges
Amplification, voltage signal of the 5th gain channel for 5 Ω or more resistance values amplify；
S2: wherein the Standard resistance range of the second gain channel service is (0.5B, 1.5B), and the gain channel is in setting gain factor
When, so that voltage signal is amplified to the full scale voltage close to analog-digital converter, so that the resistance value measurement of the Standard resistance range is the most
Precisely；
S3: 80% will be amplified to the voltage signal of adjacent first gain channel of the second gain channel and third gain channel
The size of digital analog converter full scale voltage；
S4: the voltage signal of the 4th gain channel is amplified to the size of 60% digital analog converter full scale voltage；
S5: the voltage signal of the 5th gain channel is amplified to the size of 50% digital analog converter full scale voltage.
4. the ground loop resistance measurement method of power test grounding intelligent prior-warning device according to claim 1, special
Sign is that the constant-current source measuring unit and the constant pressure source measuring unit replace work within each measurement of Grounding Resistance period
Make.
5. the ground loop resistance measurement method of power test grounding intelligent prior-warning device according to claim 4, special
Sign is that the duty cycle of ground resistance measurement module is set as 80ms, and wherein constant-current source measures cell operation 60ms, and constant pressure source is surveyed
Cell operation 20ms is measured, constant pressure source increases the stability of measurement of Grounding Resistance as additional survey mode.
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| CN201810012016.2A CN109459617B (en) | 2018-01-05 | 2018-01-05 | Grounding loop resistance measurement method of power test grounding intelligent early warning device |
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| CN201810012016.2A CN109459617B (en) | 2018-01-05 | 2018-01-05 | Grounding loop resistance measurement method of power test grounding intelligent early warning device |
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| CN109459617B CN109459617B (en) | 2020-12-22 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111458579A (en) * | 2020-03-23 | 2020-07-28 | 朔黄铁路发展有限责任公司 | Electrical test apparatus, electrical test method, electrical test device, electrical test apparatus, and storage medium |
| CN115856439A (en) * | 2022-12-02 | 2023-03-28 | 深圳供电局有限公司 | Grounding resistance measuring method |
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| CN103813595A (en) * | 2014-02-24 | 2014-05-21 | 南京创维平面显示科技有限公司 | Efficient power source capable of supplying electricity in constant voltage and constant current alternation mode |
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| CN111458579A (en) * | 2020-03-23 | 2020-07-28 | 朔黄铁路发展有限责任公司 | Electrical test apparatus, electrical test method, electrical test device, electrical test apparatus, and storage medium |
| CN115856439A (en) * | 2022-12-02 | 2023-03-28 | 深圳供电局有限公司 | Grounding resistance measuring method |
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| CN109459617B (en) | 2020-12-22 |
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