CN109596934A - A kind of double split-core type meter mensurations of secondary circuit multipoint earthing - Google Patents
A kind of double split-core type meter mensurations of secondary circuit multipoint earthing Download PDFInfo
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- CN109596934A CN109596934A CN201811460282.8A CN201811460282A CN109596934A CN 109596934 A CN109596934 A CN 109596934A CN 201811460282 A CN201811460282 A CN 201811460282A CN 109596934 A CN109596934 A CN 109596934A
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- secondary circuit
- branch
- line
- core type
- type meter
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
Abstract
The present invention discloses a kind of double split-core type meter mensurations of secondary circuit multipoint earthing, secondary circuit N line is detected with system detector split-core type meter first, by the way that secondary circuit N line earth impedance value R is calculated, then system detector is according to judging whether the automatically derived conclusion of 200 Ω of R >, N600 system whether there is multipoint earth faults, if there is multipoint earth faults, system detector is by R value impedance transition at curve, and curve signal is sent to feeder line detector, then feeder line detector split-core type meter detection branch is used, the R value forming curves sended in system detector are compared and whether meet 0.9R < R branch < 1.1R according to condition R branch by the branch impedance value R branch that feeder line detector detection branch obtains, finally obtain the branch with the presence or absence of earth fault, other branch is continued to test if not；The double split-core type meter mensurations of secondary circuit multipoint earthing have without disconnecting line, the advantages of without outer connecting resistance.
Description
Technical field
The present invention relates to a kind of double split-core type meter mensurations of secondary circuit multipoint earthing.
Background technique
According to regulation in " relay protection of power system and automatic safety device anti-accident measures main points ": through zero phase of control room
Several groups of Secondary Circuit of Potential Transformer of small bus (N600) connection, only should be in control room by N600 one point earth, and each voltage is mutual
Sensor secondary neutral should be disconnected in switch yard grounding point；To guarantee that ground connection is reliable, the neutral conductor of each voltage transformer must not be connect
It is possible that the breaker or contactor etc. that disconnect.
When N600 respectively switch place ground connection or control room be grounded when, if system jam, substation ground network stream
Excessive fault current, at this moment the both ends N600 will appear potential difference, it will cause the voltage-phase of neutral point to deviate, and then influence phase
The amplitude and phase of voltage and residual voltage.So as to lead to distance protection, zero-sequence voltage injection tripping or malfunction.If
N600 poor contact will also result in the voltage-phase offset of neutral point.So each voltage transformer neutral conductor must not be connected to possibility
The breaker or contactor of disconnection, on the voltage transformer switching screen of control room, the ground connection of secondary winding must respective lead
It is connected on the grounding copper bar of screen cabinet, and cannot be using the method for concatenation.
Present N600, which looks into ground fault method, electric-resistivity method, shunting, voltage method.
Electric-resistivity method: it be by artificially access one can on-off with slide wire resistance and all the way can on-off ground line, so
The connecting line for disconnecting control room one point earth afterwards, measures the electric current on swept resistance, powers on stream to slide wire resistance and analyze, electricity
Stream, which changes, to be illustrated PT secondary circuit N600 there are two o'clock (or multiple spot) ground connection.The detection method needs external access resistive conductor
Road and the connecting line for switching and disconnecting original control room one point earth, there are security risks；Current data after test is analyzed and is needed
Want technical professional.
Shunting: it is the both ends injection DC current signal being grounded on one point, then measures one point earth with direct current split-core type meter
Electric current, the value measured and the current value of injection are compared, explanation only has one point earth if the same, if relatively large deviation
Illustrate that there are two o'clock (or multiple spot) ground connection.This method electric-resistivity method that compares can faster find Grounding, but infuse to N600
Enter the dangerous situation that external signal is likely to result in system malfunction, while it is using direct current split-core type meter, it is high-precision on the market at present
The opening radian of degree direct current split-core type meter is difficult to meet measurement request.
Voltage method: voltage method is to measure the voltage value of respective N600 over the ground by multimeter on the basis of electric-resistivity method,
If somewhere N600 line-to-earth voltage is 0 volt or several millivolts, it can tentatively judge that there is N600 grounding point on the ground.
Summary of the invention
In view of this, being not necessarily to disconnect line it is an object of the present invention to provide one kind, without the secondary circuit multiple spot of outer connecting resistance
It is grounded double split-core type meter mensurations.
In order to solve the above-mentioned technical problem, the technical scheme is that
A kind of double split-core type meter mensurations of secondary circuit multipoint earthing, are voluntarily compared by double split-core type meter measurement data and quickly judge PT
Secondary circuit whether there is multipoint earth faults, and identify which group PT secondary circuit has multipoint earthing, to achieve the above object,
The mensuration the following steps are included:
1., with system detector split-core type meter detect N600 system one point earth secondary circuit N line；
2., system detector by split-core type meter CT coil to N600 system one point earth secondary circuit N line issue modulation frequency modulation
Sinusoidal signal；
3., by modulation frequency modulation sinusoidal signal N600 system one point earth secondary circuit N line generate sensitive electromotive force
E；
4., simultaneously with feeder line detector split-core type meter detect N600 system one point earth secondary circuit N line, measure electric current I=(Ie
+I50+I1)；
5., by fast Flourier digital filtering extract current value Ie；
6., secondary circuit N line pair can be calculated according to the current value Ie of Ohm's law, induced electromotive force E and extraction
Ground resistance impedance R=E/Ie；
7., judge whether resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground；
8., if resistive impedance R is unsatisfactory for 200 Ω of R > to secondary circuit N line over the ground, N600 system without multipoint earthing therefore
Barrier；
9., if resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground, illustrate that there are multiple spots to connect for N600 system
Earth fault；
10. and then system detector sends the R value signal that detected to feeder line detector by communication module；
Feeder line detector split-core type meter detection branch is used simultaneously, measures electric current I=(Ie+I50+I1)；
Current value Ie is extracted by fast Flourier digital filtering；
Branch can be calculated to ground resistance according to the current value Ie of Ohm's law, induced electromotive force E and extraction branch
Impedance R branch=E/Ie branch；The R value signal forming curves comparison sended over simultaneously with system detector；
Judge whether branch impedance R branch meets 0.9R < R branch < 1.1R；
If meeting theThe Rule of judgment of point then illustrates N600 system, and there are an earth faults；
If being unsatisfactory forThe Rule of judgment of point then continues to search other branch trouble point.
Further, the step 4. in Ie refer to that system detector issues the electric current that measures after signal；What I50 referred to
It is N600 system one point earth secondary circuit N line original electric current itself；I1 refers to other noise jamming electric currents.
Further, the stepIn Ie refer to that system detector issues the electric current that measures after signal；What I50 referred to
It is the original electric current of N600 system branch itself；I1 refers to other noise jamming electric currents.
The technology of the present invention effect major embodiment is in the following areas: the mensuration uses the detection of system detector split-core type meter secondary first
Circuit N line, by the way that secondary circuit N line earth impedance value R is calculated, then system detector is according to judging whether 200 Ω of R >
Automatically derived conclusion, N600 system whether there is multipoint earth faults, and if there is multipoint earth faults, system detector is by R
It is worth impedance transition and is sent to feeder line detector at curve, and by curve signal, then uses feeder line detector split-core type meter detection branch, feedback
The branch impedance value R branch that line detector detection branch obtains compares the R value forming curves sended in system detector simultaneously
Whether meet 0.9R < R branch < 1.1R according to condition R branch, finally obtains the branch with the presence or absence of earth fault, if do not had
Then continue to test other branch；The double split-core type meter mensurations of the secondary circuit multipoint earthing have without disconnecting line, without external
The advantages of resistance.
Detailed description of the invention
Fig. 1 is the double split-core type meter measuring method flow charts of secondary circuit multipoint earthing of the invention；
Fig. 2 is N600 system and device test chart of the invention.
Specific embodiment
A kind of double split-core type meter mensurations of secondary circuit multipoint earthing, as shown in Figure 1.It is voluntarily compared by double split-core type meter measurement data
Quickly judge that PT secondary circuit whether there is multipoint earth faults, and identify which group PT secondary circuit has multipoint earthing, is real
Existing above-mentioned purpose, the mensuration the following steps are included:
1., with system detector split-core type meter detect N600 system one point earth secondary circuit N line；
2., system detector by split-core type meter CT coil to N600 system one point earth secondary circuit N line issue modulation frequency modulation
Sinusoidal signal；
3., by modulation frequency modulation sinusoidal signal N600 system one point earth secondary circuit N line generate sensitive electromotive force
E；
4., simultaneously with feeder line detector split-core type meter detect N600 system one point earth secondary circuit N line, measure electric current I=(Ie
+I50+I1)；
5., by fast Flourier digital filtering extract current value Ie；
6., secondary circuit N line pair can be calculated according to the current value Ie of Ohm's law, induced electromotive force E and extraction
Ground resistance impedance R=E/Ie；
7., judge whether resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground；
8., if resistive impedance R is unsatisfactory for 200 Ω of R > to secondary circuit N line over the ground, N600 system without multipoint earthing therefore
Barrier；
9., if resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground, illustrate that there are multiple spots to connect for N600 system
Earth fault；
10. and then system detector sends the R value signal that detected to feeder line detector by communication module；
Feeder line detector split-core type meter detection branch is used simultaneously, measures electric current I=(Ie+I50+I1)；
Current value Ie is extracted by fast Flourier digital filtering；
Branch can be calculated according to the current value Ie of Ohm's law, induced electromotive force E and extraction to hinder ground resistance
Anti- R branch=E/Ie branch；The R value signal forming curves comparison sended over simultaneously with system detector；
Judge whether branch impedance R branch meets 0.9R < R branch < 1.1R；
If meeting theThe Rule of judgment of point then illustrates N600 system, and there are an earth faults；
If being unsatisfactory forThe Rule of judgment of point then continues to search other branch trouble point.
In the present embodiment, the step 4. in Ie refer to that system detector issues the electric current that measures after signal；I50
Refer to N600 system one point earth secondary circuit N line original electric current itself；I1 refers to other noise jamming electric currents.
In the present embodiment, the stepIn Ie refer to that system detector issues the electric current that measures after signal；I50
Refer to the original electric current of N600 system branch itself；I1 refers to other noise jamming electric currents.
As shown in Fig. 2, voltage generator and current amplifier are that be sent into tested earth-return circuit or cable is 2.35KHz
AC constant voltage only has electric current caused by the voltage of 2.35KHz to be detected in system detector current detecting, passes through
It crosses quick Fourier number word filtering to extract, secondary circuit N line earth impedance can be calculated, distinguish whether disconnected secondary circuit has multiple spot
Failure and failure size.Only have electric current caused by the voltage of 2.35KHz to be detected in branch locator current detecting,
It is extracted by fast Flourier digital filtering, the branch earth impedance can be calculated.Exactly because in this way, just eliminating commercialization
Weak current on ground wire brought by alternating current and included high-frequency noise generated itself, so accurately measurement could be obtained
As a result, having the advantage of measurement.
The technology of the present invention effect major embodiment is in the following areas: the mensuration uses the detection of system detector split-core type meter secondary first
Circuit N line, by the way that secondary circuit N line earth impedance value R is calculated, then system detector is according to judging whether 200 Ω of R >
Automatically derived conclusion, N600 system whether there is multipoint earth faults, and if there is multipoint earth faults, system detector is by R
It is worth impedance transition and is sent to feeder line detector at curve, and by curve signal, then uses feeder line detector split-core type meter detection branch, feedback
The branch impedance value R branch that line detector detection branch obtains compares the R value forming curves sended in system detector simultaneously
Whether meet 0.9R < R branch < 1.1R according to condition R branch, finally obtains the branch with the presence or absence of earth fault, if do not had
Then continue to test other branch；The double split-core type meter mensurations of the secondary circuit multipoint earthing have without disconnecting line, without external
The advantages of resistance.
Certainly, above is representative instance of the invention, and in addition to this, the present invention can also have other a variety of specific implementations
Mode, all technical solutions formed using equivalent substitution or equivalent transformation, is all fallen within the scope of protection of present invention.
Claims (3)
1. a kind of double split-core type meter mensurations of secondary circuit multipoint earthing, it is characterised in that: voluntarily compared by double split-core type meter measurement data
Quickly judge that PT secondary circuit whether there is multipoint earth faults, and identify which group PT secondary circuit has multipoint earthing, is real
Existing above-mentioned purpose, the mensuration the following steps are included:
1., with system detector split-core type meter detect N600 system one point earth secondary circuit N line；
2., that system detector by split-core type meter CT coil issues modulation frequency modulation to N600 system one point earth secondary circuit N line is sinusoidal
Signal；
3., by modulation frequency modulation sinusoidal signal N600 system one point earth secondary circuit N line generate sensitive electromotive force E；
4., simultaneously with feeder line detector split-core type meter detect N600 system one point earth secondary circuit N line, measure electric current I=(Ie+I50
+I1)；
5., by fast Flourier digital filtering extract current value Ie；
6., according to the current value Ie of Ohm's law, induced electromotive force E and extraction secondary circuit N line can be calculated electric over the ground
Hinder impedance R；
7., judge whether resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground；
8., if resistive impedance R is unsatisfactory for 200 Ω of R > to secondary circuit N line over the ground, N600 system is without multipoint earth faults；
9., if resistive impedance R meets 200 Ω of R > to secondary circuit N line over the ground, illustrate N600 system there are multipoint earthing therefore
Barrier；
10. and then system detector sends the R value signal that detected to feeder line detector by communication module；
Feeder line detector split-core type meter detection branch is used simultaneously, measures electric current I=(Ie+I50+I1)；
Current value Ie is extracted by fast Flourier digital filtering；
Branch resistive impedance R branch over the ground can be calculated according to the current value Ie of Ohm's law, induced electromotive force E and extraction
=E/Ie branch；The R value signal forming curves comparison sended over simultaneously with system detector；
Judge whether branch impedance R branch meets 0.9R < R branch < 1.1R；
If meeting theThe Rule of judgment of point then illustrates N600 system, and there are an earth faults；
If being unsatisfactory forThe Rule of judgment of point then continues to search other branch trouble point.
2. the double split-core type meter mensurations of a kind of secondary circuit multipoint earthing as described in claim 1, it is characterised in that: the step is 4.
In Ie refer to that system detector issues the electric current that measures after signal；I50 refers to N600 system one point earth secondary circuit N
The original electric current of line itself；I1 refers to other noise jamming electric currents.
3. the double split-core type meter mensurations of a kind of secondary circuit multipoint earthing as described in claim 1, it is characterised in that: the step
In Ie refer to that system detector issues the electric current that measures after signal；I50 refers to the original electric current of N600 system branch itself；
I1 refers to other noise jamming electric currents.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811460282.8A CN109596934B (en) | 2018-11-30 | 2018-11-30 | Secondary circuit multipoint grounding double-clamp meter measuring method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811460282.8A CN109596934B (en) | 2018-11-30 | 2018-11-30 | Secondary circuit multipoint grounding double-clamp meter measuring method |
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| CN109596934A true CN109596934A (en) | 2019-04-09 |
| CN109596934B CN109596934B (en) | 2021-06-01 |
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| CN201811460282.8A Active CN109596934B (en) | 2018-11-30 | 2018-11-30 | Secondary circuit multipoint grounding double-clamp meter measuring method |
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Cited By (3)
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| CN111505533A (en) * | 2020-05-06 | 2020-08-07 | 南京四联共创电气工程有限公司 | Ground wire test terminal and system and ground wire test method under uninterrupted power supply working condition |
| CN111856179A (en) * | 2020-06-24 | 2020-10-30 | 国网天津市电力公司电力科学研究院 | Transformer substation secondary grounding monitoring device and method |
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| CN109596934B (en) | 2021-06-01 |
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