CN111856143A - Grounding impedance test method and device for eliminating mutual inductance influence - Google Patents
Grounding impedance test method and device for eliminating mutual inductance influence Download PDFInfo
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- CN111856143A CN111856143A CN202010773814.4A CN202010773814A CN111856143A CN 111856143 A CN111856143 A CN 111856143A CN 202010773814 A CN202010773814 A CN 202010773814A CN 111856143 A CN111856143 A CN 111856143A
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- 238000005259 measurement Methods 0.000 abstract description 5
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- G—PHYSICS
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- 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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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
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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
- G01R27/08—Measuring resistance by measuring both voltage and current
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Abstract
The application provides a grounding impedance testing method and device for eliminating mutual inductance influence. The method comprises the steps of obtaining a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter; and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value. The device includes ground connection impedance tester, earthing device, shielding voltage line, voltage utmost point, electric current line and electric current utmost point, through at large-scale earthing device test wiring in-process, lays shielding voltage line, shielding voltage line is the voltage test wire that possesses the shielding function, shields the interference signal of different frequency current signal through space coupling to shielding voltage line, and the voltage signal that the voltage utmost point was tested is for not having mutual inductive superposition's voltage value to eliminate the mutual inductance influence of lead wire, reach accurate measurement ground connection impedance's purpose.
Description
Technical Field
The application relates to the technical field of grounding of power equipment of a power system, in particular to a grounding impedance testing method and device for eliminating mutual inductance influence.
Background
With the continuous appearance of high-capacity and high-voltage power grids, the system grounding current is larger and larger, and the potential rise on the grounding grid of the power generation and transformation station becomes higher and higher. In order to ensure the safety of equipment and personnel, higher requirements are put forward on the reliability of the grounding network. The measurement result of the grounding impedance of the grounding network is often influenced by a plurality of factors, so that the reduction of the influence of various interference factors is important for accurately measuring the grounding impedance of the grounding network.
The traditional high-current method needs larger equipment capacity and the section diameter of a test wire is large enough, so that the workload of the high-current method is very large, and the method is not adopted slowly. Factors influencing the accuracy of the grounding impedance measurement include: the method comprises the following steps of (1) soil moisture condition, specification and size of a grounding network, a line lightning conductor, connection of a pole tower and the grounding network, skin effect of the earth, mutual inductance between an underground metal pipeline, a structure and a long-distance wire and external electromagnetic environment.
The different-frequency method measures the grounding impedance of the grounding device, and the currents higher than and lower than the power frequency are respectively used for measuring once and then converted into the resistance value when the power frequency is reached. The pilot frequency testing technology can effectively eliminate external interference, completely extracts a test signal, and easily eliminates the external power frequency interference when the frequency of the test signal deviates far from the power frequency. Due to the fact that the voltage line is parallel to the current line in a long distance in a straight line mode, when the grounding impedance is measured, the mutual inductance between the voltage line and the current line can enable a test result to generate certain errors.
Disclosure of Invention
In order to solve the above problems, the present application provides a method and an apparatus for testing ground impedance to eliminate mutual inductance influence, so as to solve the problem in the prior art that mutual inductance between long-distance wires influences the measurement of ground impedance.
In order to achieve the purpose, the application is realized by the following technical scheme:
in one aspect, a method for testing ground impedance to eliminate mutual inductance influence includes:
acquiring a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter;
and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value.
Optionally, the determining the ground impedance according to the zero potential point voltage value and the pilot frequency current value includes:
and calculating and determining the grounding impedance by using ohm's law according to the voltage value of the zero potential point and the pilot frequency current value.
In another aspect, a ground impedance testing apparatus for eliminating mutual inductance influence includes: the grounding device comprises a grounding impedance tester, a grounding device, a shielding voltage wire, a voltage electrode, a current wire and a current electrode;
wherein, the ground impedance tester includes: the device comprises a shell, a voltmeter, an ammeter, a first terminal, a second terminal, a third terminal and a fourth terminal;
the shell is grounded;
the voltmeter and the ammeter are arranged in the shell;
the first, second, third and fourth terminals are disposed on a surface of the housing;
the second terminal and the third terminal are connected with the voltmeter;
the first terminal and the fourth terminal are connected with the ammeter;
the first terminal and the second terminal are connected with the grounding device through wires;
the voltage electrode is connected to the third terminal through the shielding voltage line;
the current electrode is connected with the fourth terminal through the current line.
Optionally, the shielding voltage line includes: the conductor, the insulating layer, the shielding layer and the sheath layer are arranged from inside to outside in sequence;
one end of the conductor is connected with the third terminal, and the other end of the conductor is connected with the voltage electrode;
one end of the shielding layer is connected with the shell.
According to the technical scheme, the ground impedance testing method and device for eliminating mutual inductance influence are provided. The method comprises the steps of obtaining a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter; and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value. The device includes ground connection impedance tester, earthing device, shielding voltage line, voltage utmost point, electric current line and electric current utmost point, through at large-scale earthing device test wiring in-process, lays shielding voltage line, shielding voltage line is the voltage test wire that possesses the shielding function, shields the interference signal of different frequency current signal through space coupling to shielding voltage line, and the voltage signal that the voltage utmost point was tested is for not having mutual inductive superposition's voltage value to eliminate the mutual inductance influence of lead wire, reach accurate measurement ground connection impedance's purpose.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a connection diagram of a grounding impedance testing apparatus according to an embodiment of the present application;
fig. 2 is a schematic cross-sectional view of the shield voltage line of fig. 1.
The device comprises a 1-grounding impedance tester, a 11-shell, a 12-voltmeter, a 13-ammeter, a 2-grounding device, a 3-shielding voltage line, a 31-conductor, a 32-insulating layer, a 33-shielding layer, a 34-sheath layer, a 4-voltage pole, a 5-current line, a 6-current pole, a C1-first terminal, a C2-fourth terminal, a P1-second terminal and a P2-third terminal.
Detailed Description
In order to make the technical means, the creation features, the achievement purposes and the effects of the application easy to understand, the application is further described in the following with the specific embodiments.
In one aspect, a method for testing ground impedance to eliminate mutual inductance influence includes:
acquiring a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter; and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value. The grounding impedance tester 1 can apply a pilot frequency current signal, inject the pilot frequency current signal into the ground at the current pole 6 through the current line 5, and measure the magnitude of the current value through the current meter 12. The zero potential point voltage is measured by the shield voltage line 3 using the voltage electrode 4, and the value of the zero potential point voltage is measured by the voltmeter 13.
In some embodiments, said determining a ground impedance based on said zero potential point voltage value and said pilot frequency current value comprises: and calculating and determining the grounding impedance by using ohm's law according to the voltage value of the zero potential point and the pilot frequency current value. The voltage electrode 4 is used for measuring a voltage value of a zero potential point, the ammeter 13 is used for measuring a pilot frequency current value, and the grounding impedance of the grounding device 2 is calculated through ohm's law.
On the other hand, fig. 1 is a connection diagram of a ground impedance testing apparatus according to an embodiment of the present application, and as shown in fig. 1, the ground impedance testing apparatus for eliminating mutual inductance influence includes a ground impedance tester 1, a grounding device 2, a shielding voltage line 3, a voltage electrode 4, a current line 5, and a current electrode 6. In use, the grounding device 2 is grounded. The voltage pole 4 is a potential rod, one end of the voltage pole 4 is pointed, and when the voltage pole 4 is used, the voltage pole is driven into the ground, and the other end of the voltage pole 4 is connected to the third terminal P2 of the grounding resistance tester 1 through the shielding voltage wire 3. The current pole 6 is a current rod, one end of the current pole 6 is pointed, and when the current pole 6 is used, the current pole is driven into the ground, and the other end of the current pole 6 is connected to the fourth terminal C2 of the ground impedance tester 1 through a current wire 5.
The grounding impedance tester 1 applies a pilot frequency current signal, the pilot frequency current signal passes through the current line 5 and is injected into the ground at the current pole 6, the current signal flows back to the grounding impedance tester 1 from the grounding device 2 through a lead, and the voltage pole 4 measures the voltage of a zero potential point through the shielding voltage line 3.
Wherein, the ground impedance tester 1 includes: the device comprises a shell 11, a voltmeter 12, an ammeter 13, a first terminal C1, a second terminal P1, a third terminal P2 and a fourth terminal C2;
the housing 11 is grounded;
the voltmeter 12 and the ammeter 13 are arranged in the shell 11; the voltmeter 12 is used for measuring the zero potential point voltage, and the ammeter 13 is used for measuring the magnitude of the current value.
The first terminal C1, the second terminal P1, the third terminal P2 and the fourth terminal C2 are disposed on the surface of the housing 11;
the second terminal P1 and the third terminal P2 are connected with the voltmeter 12; for measuring the voltage.
The first terminal C1 and the fourth terminal C2 are connected with the ammeter 13; for measuring the current.
The first terminal C1 and the second terminal P1 are connected with the grounding device 2 through wires;
the voltage pole 4 is connected to the third terminal P2 via the shielding voltage line 3;
the current electrode 6 is connected to the fourth terminal C2 via the current line 5.
In some embodiments, fig. 2 is a schematic cross-sectional view of the shielding voltage line of fig. 1, and as shown in fig. 2, the shielding voltage line 3 includes: the conductor 31, the insulating layer 32, the shielding layer 33 and the sheath layer 34 are arranged from inside to outside in sequence;
one end of the conductor 31 is connected to the third terminal P2, and the other end of the conductor 31 is connected to the voltage electrode 4;
one end of the shielding layer 33 is connected to the housing 11, and the other end of the shielding layer 33 is suspended. The shielding layer 33 is led out and then connected with the shell 11 of the grounding impedance tester 1, and the shell 11 is reliably grounded.
Mutual inductance generated between the long-distance parallel current line 5 and the shielding voltage line 3 exists on the shielding layer 33 due to the existence of the shielding layer 33 on the shielding voltage line 3, interference signals coupled to the voltage line by the mutual inductance exist on the shielding layer 33, the shielding layer 33 is reliably grounded by being connected with the shell 11 of the grounding impedance tester 1, and at the moment, the mutual inductance influence of the long-distance wires is eliminated by the voltage signals measured by the conductor 31 of the shielding voltage line 3, so that the measuring accuracy is ensured.
According to the technical scheme, the ground impedance testing method and device for eliminating mutual inductance influence are provided. The method comprises the steps of obtaining a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter; and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value. The device includes ground connection impedance tester 1, earthing device 2, shielding voltage line 3, voltage utmost point 4, current line 5 and current utmost point 6, through at large-scale earthing device test wiring in-process, lays shielding voltage line 3, shielding voltage line 3 is the voltage test wire that possesses the shielding function, shields the interference signal of different frequency current signal through space coupling to shielding voltage line 3, and the voltage signal that voltage utmost point 4 was tested is the superimposed voltage value of no mutual inductance to eliminate the mutual inductance influence of lead wire, reach the purpose of accurate measurement ground connection impedance.
The embodiments of the present application have been described in detail, but the description is only for the preferred embodiments of the present application and should not be construed as limiting the scope of the application. All equivalent changes and modifications made within the scope of the present application shall fall within the scope of the present application.
Claims (4)
1. A ground impedance test method for eliminating mutual inductance influence is characterized by comprising the following steps:
acquiring a zero potential point voltage value measured by a voltmeter and a pilot frequency current value measured by an ammeter;
and determining the grounding impedance according to the zero potential point voltage value and the pilot frequency current value.
2. The method for testing ground impedance to eliminate mutual inductance influence according to claim 1, wherein the determining ground impedance according to the zero potential point voltage value and the pilot frequency current value comprises:
and calculating and determining the grounding impedance by using ohm's law according to the voltage value of the zero potential point and the pilot frequency current value.
3. A ground impedance testing device for eliminating mutual inductance influence is characterized by comprising: the grounding device comprises a grounding impedance tester (1), a grounding device (2), a shielding voltage line (3), a voltage pole (4), a current line (5) and a current pole (6);
wherein the ground impedance tester (1) comprises: the device comprises a shell (11), a voltmeter (12), an ammeter (13), a first terminal (C1), a second terminal (P1), a third terminal (P2) and a fourth terminal (C2);
the shell (11) is grounded;
the voltmeter (12) and the ammeter (13) are arranged in the shell (11);
the first terminal (C1), the second terminal (P1), the third terminal (P2) and the fourth terminal (C2) are arranged on the surface of the shell (11);
the second terminal (P1) and the third terminal (P2) are connected with the voltmeter (12);
the first terminal (C1) and the fourth terminal (C2) are connected with the ammeter (13);
the first terminal (C1) and the second terminal (P1) are connected with the grounding device (2) through wires;
the voltage pole (4) is connected to the third terminal (P2) via the shielding voltage line (3);
the current pole (6) is connected to the fourth terminal (C2) via the current line (5).
4. A ground impedance test device for eliminating mutual inductance influence according to claim 3, wherein the shielding voltage line (3) comprises: the cable comprises a conductor (31), an insulating layer (32), a shielding layer (33) and a sheath layer (34) which are arranged from inside to outside in sequence;
one end of the conductor (31) is connected to the third terminal (P2), and the other end of the conductor (31) is connected to the voltage electrode (6);
one end of the shielding layer (33) is connected with the shell (11).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010773814.4A CN111856143A (en) | 2020-08-04 | 2020-08-04 | Grounding impedance test method and device for eliminating mutual inductance influence |
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| CN202010773814.4A CN111856143A (en) | 2020-08-04 | 2020-08-04 | Grounding impedance test method and device for eliminating mutual inductance influence |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112557759A (en) * | 2020-12-02 | 2021-03-26 | 云南电力技术有限责任公司 | Grounding impedance test method of grounding device |
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Application publication date: 20201030 |