CN107192885A - Using alien frequencies, the method for high-current test large hydropower station Grounding impedance - Google Patents
Using alien frequencies, the method for high-current test large hydropower station Grounding impedance Download PDFInfo
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- CN107192885A CN107192885A CN201710351530.4A CN201710351530A CN107192885A CN 107192885 A CN107192885 A CN 107192885A CN 201710351530 A CN201710351530 A CN 201710351530A CN 107192885 A CN107192885 A CN 107192885A
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- 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
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Abstract
The present invention provides a kind of use alien frequencies, the method for high-current test large hydropower station Grounding impedance, solves the big problem of large hydropower station Grounding testing impedance difficulty, the technical scheme is that：Using alien frequencies, high-current test Grounding impedance, export sine wave test current from variable-frequency power sources and use testing transformer isolation and amplifier.The present invention can improve the accuracy of grounded screen test data, and the impedance ground value of tested grounded screen, grounding resistance, reactance value are calculated by test data, judge whether laying for grounded screen meets the requirement of power plant safety service requirement and design according to these data.
Description
Technical field
The present invention relates to earth loop impedance test field, more particularly, to one kind using alien frequencies, the large-scale water power of high-current test
Stand the method for Grounding impedance.
Background technology
Chinese large-sized power station generally has voltage class height, single-machine capacity big and most mountains for building geologic structure complexity in
Area, the grounded screen of these large hydropower stations all has huge obvious area, dispersed placement, contacts loose, soil resistivity height
And it is uneven the characteristics of.The method of existing normally grounded testing impedance, one is power current method of testing, and this method of testing is on mountain
It is vulnerable to the influence of out-of-balance current in ground in the crisscross complicated landform in paddy river, causes test data inaccurate；Two are
Using frequency conversion instrument test method, this measuring method effectively avoids the influence of out-of-balance current in ground.But large hydropower station
The area of grounded screen is huge, and its impedance ground design load is small, by providing the Ω of the value ≯ 0.5, or even the Ω of ＜ 0.2.With the tester
The maximum output current 5A of device is calculated, then the upper measured voltage maximum ≯ 2.5V of equipotential line test, or even ＜ 1V, so small
Voltage is easy to be influenceed by induced voltage and cause the untrue of test data.For these reasons, establishing criteria is existing
Two kinds of method of testings be all difficult accurately and efficiently to large hydropower station Grounding impedance measurement, so as to large-scale water power
The operation and safe and stable operation stood bring many difficulties.
The content of the invention
It is an object of the invention to：The problem of existing for prior art is big using alien frequencies, high-current test there is provided one kind
The method of type power station Grounding impedance, solves the big problem of large hydropower station Grounding testing impedance difficulty.
The goal of the invention of the present invention is achieved through the following technical solutions：
A kind of use alien frequencies, the method for high-current test large hydropower station Grounding impedance, it is characterised in that the party
Method includes：
Using GPS location and record the test point of tested grounded screen, electric current pole, the longitude and latitude of potential pole；
Electric current pole and potential pole are arranged, and by three-phase test plant-grid connection variable-frequency power sources, by the voltage output of variable-frequency power sources
End is connected with the input of isolating transformer, and an output end of isolating transformer is accessed into one end of testing current line, will
The other end of testing current line is connected with electric current pole, by another output end of isolating transformer seal in after ammeter with test
Point be connected, one end of potential test line is connected with potential pole, the other end access voltmeter one end, by the another of voltmeter
End is connected with test point；
During experiment, adjustment variable-frequency power sources to the frequency needed, by zero up-flow, when electric current rises to more than 100A, reads this
The voltage value tested out and current values are carved, after then lowering the current to zero, are adjusted to test again during another frequency, similarly
Test electric current, voltage value under multiple frequencies；
The electric current tested out under different frequency, voltage value are substituted into formulaCalculate tested grounded screen
In impedance ground under different frequency, formulaThe virtual value for the electric current that expression is tested out,Represent impedance ground,Represent
The virtual value of the voltage tested out；
The voltage value and current values that are tested out under two different frequencies are substituted into formula respectivelyAnd two groups of data simultaneous composition equation groups are calculated into grounding resistance, inductance value respectively,
In formulaRepresent virtual value, the R of electric current tested outgRepresent that grounding resistance, f represent practical frequency, LgRepresent in impedance ground
Inductance value,Represent the virtual value of voltage tested out.
As further technical scheme, before GPS location, using each ground connection of continuity test instrument to tested grounded screen
The interconnection of unit is detected.
As further technical scheme, during arrangement electric current pole, at the actual geographic position of electric current pole, selection soil compared with
Thick, moist part is squeezed into soil using angle steel or round steel, and depth is more than 1.5m；It is actual in potential pole when arranging potential pole
Geographical location, 1.5m in soil is squeezed into by angle steel or round steel.
As further technical scheme, when laying testing current line, river, lake should be avoided, for large hydropower station
Grounded screen can do electric current line p-wire using overhead transmission line；When laying potential test line, metal tubes and operation should be remotely descended
In transmission line of electricity, it is to avoid long section is parallel therewith, when intersecting therewith perpendicular across.
As further technical scheme, potential test line uses band screened coaxial cable.
As further technical scheme, if there is certain angle between testing current line and potential test line, ground connection resistance
Anti- needs are modified, and correction formula is
In formula, Z represents revised ground connection
Impedance, Z " represents the impedance ground before amendment, and D represents the maximum diagonal length of tested grounded screen, dPGRepresent potential pole and quilt
Survey the distance of ground connection network edge, dCGElectric current pole and the distance of tested ground connection network edge are represented, θ represents that testing current line and current potential are surveyed
Try the angle of line.
As further technical scheme, voltmeter uses frequency selective voltmeter.
Compared with prior art, the present invention has advantages below：
1st, test point, electric current pole, each point location of potential pole, d during measurement are carried out using GPSCG、dPGThe degree of accuracy energy of distance
It is effectively guaranteed；
2nd, use alien frequencies to test electric current, it is to avoid the influence of out-of-balance current in ground, improve test accuracy；
3rd, test electric current is big, and test current adds greatly assay sensitivity, is solved using variable-frequency power sources and isolating transformer
Because tested grounded screen is huge, grounded screen catercorner length is long, dCGThe corresponding increase of distance, test loop impedance is because of test electricity consumption streamline
The problem that length increases and increased；
4th, potential test line access tester uses selective frequency meter, and measurement electric voltage frequency is corresponding with test power frequency,
The influence of exclusive PCR voltage, improves test accuracy；
5th, test data includes impedance ground, grounding resistance, the inductance value of grounded screen, is the analysis of test data, judges
Provide convenience；
6th, the present invention using alien frequencies, high current by test with electric current pole injection test electric current, test electric current through the earth and
Large hydropower station grounded screen and test equipment formation test loop, and according to test guidance measurement potential pole and the same frequency of test electric current
The voltage of rate, you can the earth loop impedance test value of grounded screen must be tested, then Adjustment Tests frequency can be obtained separately again according to the method
The connection composition equation group of measurement data twice simultaneously can be respectively obtained ground connection by the earth loop impedance test value under one frequency, repeatedly measurement
Grounding resistance, the inductance value of net, it is convenient to judge whether large hydropower station grounded screen meets the requirement of safe operation and design.
Brief description of the drawings
Fig. 1 is test philosophy figure of the invention.
Embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment
The present invention relates to a kind of method of testing of large hydropower station Grounding impedance, to large hydropower station grounded screen
The accuracy of grounded screen test data can be improved, and calculate tested grounded screen by test data by applying alien frequencies, high current
Impedance ground value, grounding resistance, reactance value, judge whether laying for grounded screen meets power plant safety operation according to these data
It is required that and design requirement.
It is an object of the present invention to provide large hydropower station Grounding testing impedance accurately effective method, and according to survey
Test result inspection is tested whether grounded screen meets design and the requirement of specification and code, ensures large hydropower station safety and stability fortune
OK, provided for the test of large hydropower station grounded screen from now on and refer to and promote, solve large hydropower station Grounding testing impedance
The big problem of difficulty.The technical scheme is that：Using alien frequencies, high-current test Grounding impedance, from variable-frequency electric
Source exports sine wave test current and uses testing transformer isolation and amplifier., it is necessary to ensure large-scale water before the inventive method is carried out
The installations such as each buried level in power station, ground wire, independent lightning rod, lightning conducter, and unit is connected to each other to form one
Just possesses experimental condition after individual entirety.Specific test procedure is as follows：
Step 1: grounded screen integrity checking：It is mutual to each ground unit for being tested grounded screen using continuity test instrument
Connection is detected, can effectively judge whether grounded screen unit is reliable, effectively connection；
Step 2: satellite fix：First it is being tested the test point of grounded screen with GPS (test point is provided with tested earthing or grounding means G)
Longitude and latitude is recorded in positioning, and electric current pole, potential pole are determined further according to tested grounded screen maximum diagonal length.Arrive and have determined that respectively
With GPS location and longitude and latitude is recorded on good electric current pole, potential pole actual geographic position, according to testing each longitude and latitude put
Make test satellite mapping；
Step 3: arrangement electric current pole, potential pole：At the actual geographic position of electric current pole, thicker, the moist portion of selection soil
Point squeezed into using angle steel or round steel in soil, depth is squeezed into soil preferably more than 1.5m according to testing size of current and can increase
Earthing pole.At potential pole actual geographic position, choose suitable position and angle steel or round steel are squeezed into 1.5m in soil；
Step 4: testing equipment, instrument and instrument selection：Experiment power supply use converter plant, output waveform for sine wave,
Output voltage AC0~350V 30~300Hz of frequency continuously adjustabes, capacity 200kW, isolating transformer 400V/1200V, capacity
150kVA, selective frequency meter, ammeter, voltmeter, current transformer；
Step 5: test electricity consumption streamline (i.e. testing current line), equipotential line (i.e. potential test line) are laid：Test electric current
Line selection takes suitable line footpath to be laid from test point to electric current pole, lays to try one's best and avoids river, lake, is connect for large hydropower station
Earth mat can make electric current line using overhead transmission line.Equipotential line uses band screened coaxial cable artificially to lay, and laying equipotential line should try one's best
Metal tubes and operating transmission line of electricity are remotely descended, it is to avoid long section is parallel therewith, perpendicular across noting subtracting when intersecting therewith
The influence of mutual inductance between low current line and equipotential line.
Step 6: test connection and test：By AC380V three-phase test plant-grid connection variable-frequency power sources f, variable-frequency power sources f electricity
Pressure output end is connected with isolating transformer T input, an isolating transformer T output end access to testing current line and with
Electric current pole C is connected, and isolating transformer T another output end seals in ammeter A and is connected with tested earthing or grounding means G, electricity
Bit test line is connected with potential pole P, and in test point access voltmeter V one end, the other end of voltmeter and tested ground connection dress
G is put to be connected.Variable-frequency power sources is adjusted during experiment to the frequency needed, by zero up-flow, electric current more than 100A is risen into, by electric current liter
Test voltage this moment is read simultaneously to more than 100A；Then, after lowering the current to zero, it is adjusted to test again during another frequency,
Similarly test electric current, voltage value under each frequency；
Step 7: test data is calculated：The electric current tested out under different frequency, voltage data can be calculated as follows
The data tested out under two different frequencies are separately substituted into public affairs by the impedance ground gone out under tested grounded screen different frequency respectively
Formula, and two groups of data cube computations composition equation groups can be calculated into grounding resistance, inductance value respectively.
Its formula is：
Formula 1 illustrates：- measured current virtual value (A)；- impedance ground (Ω)；Rg- grounding resistance (Ω)；Lg—
Inductance value (H) in impedance ground；F-practical frequency (Hz)；- measurement voltage virtual value (V).
If because actual geographic position can not meet experiment needs in experiment, causing test electricity consumption streamline and test equipotential line
There is certain angle, then test data needs amendment；
Its correction formula is：
Formula 2 illustrates：Z-revised impedance ground；Impedance ground (Ω) before Z "-amendment；D-subject earthing or grounding means
Maximum diagonal length (m)；dPGThe distance (m) of-potential pole and subject earthing or grounding means edge；dCG- electric current pole is grounded with subject
The distance (m) at device edge；The angle (°) of θ-electric current line and equipotential line.
Step 8: test data analysis judges：Ground connection device to test is improved with the method measuring accuracy and sensitivity,
Can effective exclusive PCR.Test data contains the impedance ground, grounding resistance, inductance value many kinds of parameters of tested earthing or grounding means,
Whether these parameters can be to the large hydropower station grounded screens run by corrosion, destruction, if meet safe operation and provide ginseng
Examine data, to newly-built large hydropower station grounded screen lay whether meet design and code the need for objective and accurate sentence
It is disconnected.
The present invention injects test electric current by test using alien frequencies, high current with electric current pole, and test electric current is through the earth and greatly
Type power station grounded screen and test equipment formation test loop, and according to test guidance measurement potential pole and test electric current same frequency
Voltage, you can must be tested the earth loop impedance test value of grounded screen, then Adjustment Tests frequency can obtain another again according to the method
The connection composition equation group of measurement data twice simultaneously can be respectively obtained grounded screen by the earth loop impedance test value under frequency, repeatedly measurement
Grounding resistance, inductance value, it is convenient to judge whether large hydropower station grounded screen meets the requirement of safe operation and design.This hair
Bright method of testing is in Xiangjiabahydropower project, Jinping Hydroelectric Power Station, Da Gang Mountain power station, pavilion saliva power station, gold Ping Shui
Power station, Ka Jiwa power stations, Xianju, Zhejiang hydroenergy storage station are tested, and result of the test is very satisfied.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, it is noted that all
Any modifications, equivalent substitutions and improvements made within the spirit and principles in the present invention etc., should be included in the guarantor of the present invention
Within the scope of shield.
Claims (7)
1. a kind of use alien frequencies, the method for high-current test large hydropower station Grounding impedance, it is characterised in that this method
Including：
Using GPS location and record the test point of tested grounded screen, electric current pole, the longitude and latitude of potential pole；
Arrange electric current pole and potential pole, and by three-phase test plant-grid connection variable-frequency power sources, by the voltage output end of variable-frequency power sources with
The input of isolating transformer is connected, and an output end of isolating transformer is accessed into one end of testing current line, by electric current
The other end of p-wire is connected with electric current pole, by another output end of isolating transformer seal in after ammeter with test point phase
Connection, one end of potential test line be connected with potential pole, one end of other end access voltmeter, by the other end of voltmeter and
Test point is connected；
During experiment, adjustment variable-frequency power sources to the frequency needed, by zero up-flow, when electric current rises to more than 100A, reading is surveyed this moment
The voltage value and current values tried out, after then lowering the current to zero, is adjusted to test again during another frequency, similarly tests
Electric current, voltage value under multiple frequencies；
The electric current tested out under different frequency, voltage value are substituted into formulaCalculate tested grounded screen different
In impedance ground under frequency, formulaThe virtual value for the electric current that expression is tested out,Represent impedance ground,Expression is tested out
Voltage virtual value；
The voltage value and current values that are tested out under two different frequencies are substituted into formula respectivelyAnd two groups of data simultaneous composition equation groups are calculated into grounding resistance, inductance value respectively,
In formulaRepresent virtual value, the R of electric current tested outgRepresent that grounding resistance, f represent practical frequency, LgRepresent in impedance ground
Inductance value,Represent the virtual value of voltage tested out.
2. a kind of use alien frequencies according to claim 1, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that before GPS location, the interconnection using continuity test instrument to each ground unit of tested grounded screen
Detected.
3. a kind of use alien frequencies according to claim 1, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that during arrangement electric current pole, at the actual geographic position of electric current pole, thicker, the moist part of selection soil is used
Angle steel or round steel are squeezed into soil, and depth is more than 1.5m；When arranging potential pole, at potential pole actual geographic position, by angle steel
Or round steel squeezes into 1.5m in soil.
4. a kind of use alien frequencies according to claim 1, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that when laying testing current line, should avoid river, lake, can utilize built on stilts for large hydropower station grounded screen
Circuit does electric current line p-wire；When laying potential test line, metal tubes and operating transmission line of electricity should be remotely descended, it is to avoid
Long section is parallel therewith, when intersecting therewith perpendicular across.
5. a kind of use alien frequencies according to claim 4, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that potential test line uses band screened coaxial cable.
6. a kind of use alien frequencies according to claim 1, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that if there is certain angle between testing current line and potential test line, impedance ground needs to be modified,
Correction formula is
In formula, Z represents revised impedance ground,
Z " represents the impedance ground before amendment, and D represents the maximum diagonal length of tested grounded screen, dPGRepresent potential pole and tested ground connection
The distance of network edge, dCGRepresent electric current pole and the distance of tested ground connection network edge, θ represents testing current line and potential test line
Angle.
7. a kind of use alien frequencies according to claim 1, the side of high-current test large hydropower station Grounding impedance
Method, it is characterised in that voltmeter uses frequency selective voltmeter.
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| CN111025024A (en) * | 2019-12-20 | 2020-04-17 | 三峡大学 | Method and device for measuring grounding impedance of transformer substation grounding grid based on actual measurement and simulation |
| CN111641096A (en) * | 2020-04-27 | 2020-09-08 | 国网辽宁省电力有限公司电力科学研究院 | Construction process of conductive polymer material grounding grid |
| CN111983327A (en) * | 2020-07-15 | 2020-11-24 | 大唐水电科学技术研究院有限公司 | Method for measuring grounding impedance of large grounding grid |
| CN112345832A (en) * | 2020-10-09 | 2021-02-09 | 国网山西省电力公司长治供电公司 | Grounding grid grounding resistance test system and method based on GPS |
| CN113899952A (en) * | 2021-10-26 | 2022-01-07 | 西安微电子技术研究所 | Automatic impedance testing system and method |
| WO2022157800A1 (en) * | 2021-01-19 | 2022-07-28 | Jef Techno Solutions Pvt Ltd | System for detecting an electrical grounding intergrid integrity |
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| CN111025024A (en) * | 2019-12-20 | 2020-04-17 | 三峡大学 | Method and device for measuring grounding impedance of transformer substation grounding grid based on actual measurement and simulation |
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| CN111641096A (en) * | 2020-04-27 | 2020-09-08 | 国网辽宁省电力有限公司电力科学研究院 | Construction process of conductive polymer material grounding grid |
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| CN112345832B (en) * | 2020-10-09 | 2024-05-24 | 国网山西省电力公司长治供电公司 | GPS-based grounding network grounding resistance testing system and method |
| WO2022157800A1 (en) * | 2021-01-19 | 2022-07-28 | Jef Techno Solutions Pvt Ltd | System for detecting an electrical grounding intergrid integrity |
| CN113899952A (en) * | 2021-10-26 | 2022-01-07 | 西安微电子技术研究所 | Automatic impedance testing system and method |
| CN113899952B (en) * | 2021-10-26 | 2023-07-28 | 西安微电子技术研究所 | Automatic impedance testing system and method |
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