CN109342821A - Impedance ground and its resistive component measurement method, device and earth loop impedance test instrument - Google Patents
Impedance ground and its resistive component measurement method, device and earth loop impedance test instrument Download PDFInfo
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- CN109342821A CN109342821A CN201810941927.3A CN201810941927A CN109342821A CN 109342821 A CN109342821 A CN 109342821A CN 201810941927 A CN201810941927 A CN 201810941927A CN 109342821 A CN109342821 A CN 109342821A
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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
Abstract
The invention discloses a kind of impedance ground and its resistive component measurement methods, device and earth loop impedance test instrument, belong to engineering measuring technology field.Method: apply the first test current to grounded screen, the first test current is direct current or square wave current；Determine that the first test voltage, the first test voltage are the voltage that the first test current generates on the resistive component of Grounding impedance；Based on the first test current and the first test voltage, the resistive component of Grounding impedance is calculated；Apply the second test current to grounded screen, the second test current is sine-wave current, and the frequency of the first, second test current is 10Hz~60Hz；Determine that the second test voltage, the second test voltage are the voltage that the second test current generates in grounded screen；The modulus value of impedance ground is calculated based on the second test current and the second test voltage；The phase angle of magnitude calculation impedance ground based on resistive component and impedance ground；The magnitude calculation impedance ground of phase angle and impedance ground based on impedance ground.
Description
Technical field
The present invention relates to engineering measuring technology field, in particular to a kind of impedance ground and its resistive component measurement method,
Device and earth loop impedance test instrument.
Background technique
Grounded screen is to ensure that the basis of each main structure reliability service and personal safety in electric system.Determine power train
Each main structure in system, such as substation etc., could put into operation after construction or whether running grounded screen needs
The important evidence of transformation is whether the impedance ground and its relevant parameter of grounding net of transformer substation meet the requirements.Impedance ground is one
A plural number, resistive component and induction reactance component including impedance ground.Power-frequency earthing impedance (hereinafter referred to as impedance ground) refers to work
The impedance that ground connection medium is presented when frequency electric current is to the earth diffusing.
The method of measurement impedance ground includes the following steps at present.
Firstly, the modulus value of the impedance ground using three electrode method measurement grounded screen | Z |.As shown in Figure 1, being existed by current source I
Apply a test current I between electric current pole C and tested grounded screen Gm, test current ImIt flows out, leads to from the C1 terminal of current source I
It crosses p-wire and is connected to electric current pole C with entering, connect by greatly returning to grounded screen G, then from the reflux point B of grounded screen G by p-wire
To the C2 terminal of current source I, current loop is formed.Voltmeter V measures test current ImIt is produced between voltage pole P and grounded screen G
Raw voltage U.Mono- terminal of voltmeter V is P1, is connected to voltage pole P by p-wire；Another terminal of voltmeter V is P2, is led to
Cross the reflux point B that p-wire is connected to grounded screen G.According to Ohm's law, the impedance ground modulus value of grounded screen | Z |=U/Im。
Secondly, using the phase angle theta of cross zero detecting method measurement impedance ground.Specifically, in measurement test current ImWhen it is synchronous
At the time of measuring test current signal zero-crossing, when measuring voltage U at the time of synchro measure voltage signal zero crossing.Based on examination
At the time of galvanoscope signal zero-crossing and at the time of voltage signal zero crossing, test current signal and voltage signal are obtained
Time difference Δ t.Phase angle is calculated by 2 π of formula θ=(Δ t/T) in cycle T based on the time difference and test current signal again
θ。
Finally, according to formula Z=| Z | ∠ θ calculates impedance ground Z.
In the implementation of the present invention, the inventor finds that the existing technology has at least the following problems:
Current source I injects grounded screen as test current source using sine-wave current, and in measurement process, due to test
The wiring of the limitation of method and landform, voltage lead (route where voltmeter) and current feed (route where current source) is more
It less can be parallel.The variation of sine-wave current size on current feed, inevitably in electricity due to the mutual inductance between voltage lead
Pressure drop is generated on voltage lead wires, brings error to voltage signal U.The error of voltage signal U will lead to impedance ground modulus value | Z | exist
There is error in error and phase angle, and so as to cause grid grounding impedance measurement result, there are large errors.
Summary of the invention
The embodiment of the invention provides a kind of impedance ground and its resistive component measurement methods, device and earth loop impedance test
Instrument can reduce influence of the Mutual Inductance Coupling to impedance ground, improve the precision of impedance ground.The technical solution is as follows:
In a first aspect, providing a kind of grid grounding impedance measurement method, which comprises
Apply the first test current to grounded screen, first test current is direct current or square wave current；
Determine that the first test voltage, first test voltage are that first test current is hindered in the Grounding
The voltage generated on anti-resistive component；
Based on first test current and first test voltage, the resistance point of the Grounding impedance is calculated
Amount；
Apply the second test current to the grounded screen, second test current is sine-wave current, first examination
The frequency of galvanoscope and the frequency of second test current are 10Hz~60Hz；
Determine that the second test voltage, second test voltage are that second test current generates in the grounded screen
Voltage；
Based on second test current and second test voltage, the modulus value of the impedance ground is calculated；
Modulus value based on the resistive component and the impedance ground, calculates the phase angle of the impedance ground；
The modulus value of phase angle and the impedance ground based on the impedance ground, calculates the impedance ground.
Optionally, the square wave current is bipolar square wave electric current, when first test current is the square wave current
When, first test voltage of determination, comprising:
Determine the voltage that positive polarity electric current generates on the resistive component；
Determine the voltage that negative polarity electric current generates on the resistive component；
The voltage and the negative polarity electric current generated on the resistive component based on the positive polarity electric current is described
The voltage generated on resistive component calculates first test voltage.
Optionally, the method also includes:
Modulus value based on the resistive component and the impedance ground calculates the induction reactance component of the impedance ground.
Second aspect provides a kind of resistive component measurement method of impedance ground, which comprises
Apply test current to grounded screen, the test current is direct current or square wave current, the frequency of the test current
Rate is 10Hz~60Hz；
Determine that test voltage, the test voltage are resistive component of the test current in the Grounding impedance
The voltage of upper generation；
Based on the test current and the test voltage, the resistive component of the Grounding impedance is calculated.
Optionally, the square wave current is bipolar square wave electric current, when the test current is the square wave current, institute
State determining test voltage, comprising:
Determine the voltage that positive polarity electric current generates on the resistive component；
Determine the voltage that negative polarity electric current generates on the resistive component；
The voltage and the negative polarity electric current generated on the resistive component based on the positive polarity electric current is described
The voltage generated on resistive component calculates the test voltage.
Optionally, the voltage that the determining positive polarity electric current generates on the resistive component, comprising:
In a cycle of the square wave current, voltage that the positive polarity electric current is generated in the grounded screen into
Row continuous sampling；
Determine the difference of two neighboring voltage in the voltage of sampling；
When the difference of the two neighboring voltage is less than or equal to difference threshold, its in the two neighboring voltage is determined
In voltage be voltage that the positive polarity electric current generates on the resistive component.
Optionally, the frequency of the test current is 45Hz~55Hz.
The third aspect, provides a kind of footing impedance measuring apparatus, and described device includes processor and memory, described to deposit
At least one instruction is stored in reservoir, described instruction is loaded by the processor and executed to realize aforementioned grid grounding impedance measurement
Operation performed by method.
Fourth aspect, provides a kind of earth loop impedance test instrument, and the earth loop impedance test instrument includes:
Power source, voltmeter and footing impedance measuring apparatus；
The footing impedance measuring apparatus is used for, and applies the first test current to grounded screen by the power source, described
First test current is direct current or square wave current；The first test voltage, the first test electricity are determined by the voltmeter
Pressure is the voltage that first test current generates on the resistive component of the Grounding impedance；Based on first examination
Galvanoscope and first test voltage, calculate the resistive component of the Grounding impedance；By the power source to institute
It states grounded screen and applies the second test current, second test current is sine-wave current, the frequency of first test current
Frequency with second test current is 10Hz~60Hz；The second test voltage is determined by the voltmeter, described
Two test voltages are the voltage that second test current generates in the grounded screen；Based on second test current and institute
The second test voltage is stated, the modulus value of the impedance ground is calculated；Modulus value based on the resistive component and the impedance ground, meter
Calculate the phase angle of the impedance ground；The modulus value of phase angle and the impedance ground based on the impedance ground, calculates the ground connection
Impedance.
5th aspect, provides a kind of resistive component measuring device of impedance ground, and described device includes processor and deposits
Reservoir is stored at least one instruction in the memory, and described instruction is loaded by the processor and executed aforementioned to realize
Operation performed by the resistive component measurement method of impedance ground.
Technical solution provided in an embodiment of the present invention has the benefit that
By applying the first test current, i.e. direct current or square wave current to grounded screen, direct current or square wave are then determined
The voltage that electric current generates on the resistive component of Grounding impedance；Due to the size of current of the square wave current in certain time
Be with direction it is constant, therefore, the constant square wave current of size of current in certain time and direction can be considered as direct current；When
When what measurement circuit flowed through is direct current, inductance is channel status to direct current in the circuit model of impedance ground, and there is no resistances
Hinder effect, at this moment the first test voltage measured on circuit model is the voltage of resistive component；Meanwhile when measurement circuit stream
When what is crossed is direct current, it can be avoided generation Mutual Inductance Coupling phenomenon between measurement circuit, eliminate brought by Mutual Inductance Coupling phenomenon
Voltage error；Based on the first test current and the first test voltage, the resistive component of Grounding impedance is calculated；Due to first
Voltage error is not present in test voltage, and the resistive component being calculated so also will be not present error, improve resistive component
Accuracy；After the modulus value for calculating impedance ground, the modulus value based on resistive component and impedance ground calculates the phase of impedance ground
Angle, as resistive component be eliminate Mutual Inductance Coupling phenomenon brought by voltage error in the case of obtain, accuracy is higher,
Therefore the phase angle accuracy of impedance ground is also relatively high；The modulus value of the phase angle based on impedance ground and impedance ground, calculating connect again
Ground impedance, since the accuracy of resistive component and the phase angle of impedance ground is higher, the accuracy of obtained impedance ground also compares
It is higher.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment
Attached drawing is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, for
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is the schematic diagram of the modulus value of the impedance ground provided by the invention using three electrode method measurement grounded screen；
Fig. 2 is the schematic diagram of the circuit model of impedance ground provided in an embodiment of the present invention；
Fig. 3 is the schematic diagram of the phase angle of impedance ground provided in an embodiment of the present invention；
Fig. 4 is the signal of mutual inductance phenomenon present in the measurement process of impedance ground modulus value provided in an embodiment of the present invention
Figure；
Fig. 5 and Fig. 6 is a kind of process of the resistive component measurement method of impedance ground provided in an embodiment of the present invention respectively
Figure；
Fig. 7 is the waveform diagram of bipolar square wave electric current provided in an embodiment of the present invention；
Fig. 8 and Fig. 9 is a kind of flow chart of grid grounding impedance measurement method provided in an embodiment of the present invention respectively；
Figure 10 is the waveform diagram of the second test current provided in an embodiment of the present invention；
Figure 11 is the resistive component measuring device or a kind of resistance of ground connection of a kind of impedance ground provided in an embodiment of the present invention
The structural block diagram of anti-measuring device；
Figure 12 is a kind of structural schematic diagram of earth loop impedance test instrument provided in an embodiment of the present invention.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, below in conjunction with attached drawing to embodiment party of the present invention
Formula is described in further detail.
Technical solution provided in an embodiment of the present invention for ease of understanding introduces impedance ground and its related ginseng first
Number.Fig. 2 shows the circuit model of impedance ground, which is resistance and inductance series model.Wherein, impedance ground Z
=R+jX.Referring to fig. 2, R is real part, that is, resistive component of impedance ground, and resistive component is able to reflect grounded screen diffusion power current
Ability, be very important parameter.It is imaginary part, that is, induction reactance component (also referred to as reactive component) of impedance ground, X=referring to Fig. 3, X
2 π fL, L are the self-induction induction reactance of grounded screen, and f is the corresponding frequency of impedance ground.J is imaginary unit.Fig. 3 is impedance ground
The schematic diagram of phase angle (also referred to as phase or phase angle) θ.| Z | for the modulus value of impedance ground, the relationship of resistive component R and phase angle is
R=| Z | the relationship of cos θ, induction reactance component X and phase angle is X=| Z | sin θ.
Mutual inductance phenomenon present in the measurement process of impedance ground modulus value is described below.Referring to fig. 4, the generation of mutual inductance
The reason is that test current ImFor sine-wave current, when size of current changes over time, circuit and voltmeter V institute where current source I
Mutual Inductance Coupling M occurs in circuit.Due to the presence of Mutual Inductance Coupling M, it can be coupled on voltage pole P and generate an error voltage Δ U.
In this way, the voltage U of actual measurement contains error voltage Δ U when applying test current Im.Ground connection resistance is calculated using voltage U
Anti- modulus value is | Z | '.Since error occurs in the modulus value of impedance ground, referring to Fig. 3, the phase angle of impedance ground also will appear error,
Phase angle with error is θ '.And the traditional method for calculating the resistive component of impedance ground is, is based on formula R=| Z | cos θ is calculated；
The traditional method for calculating the induction reactance component of impedance ground is to be based on formula X=| Z | sin θ calculates.Due to the modulus value of impedance ground
There is error with phase angle, therefore, there is error in the resistive component and induction reactance component of impedance ground, the resistive component with error and
Induction reactance component is respectively R ' and X '.
In the present embodiment, the impedance ground of grounded screen is power-frequency earthing impedance.Grounded screen can be the master of electric system
The grounded screen of body structure, main structure include each power plant, each electric substation (also known as substation), transmission of electricity, distribution line and
Load center.Power plant includes power station, thermal power plant and nuclear power station etc., and electric substation includes step-up substation and load center power transformation
Institute etc..
Fig. 5 shows a kind of resistive component measurement method of impedance ground provided in an embodiment of the present invention.It, should referring to Fig. 5
Method flow includes the following steps.
Step 101 applies test current to grounded screen.
Wherein, test current is direct current or square wave current, and the frequency of test current is 10Hz~60Hz, even lower
Frequency.
Step 102 determines test voltage.
Wherein, test voltage is the voltage that test current generates on the resistive component of Grounding impedance.
Step 103 is based on test current and test voltage, calculates the resistive component of Grounding impedance.
Then the embodiment of the present invention determines direct current or square wave current by applying direct current or square wave current to grounded screen
The voltage generated on the resistive component of Grounding impedance；Size of current and side due to the square wave current in certain time
To be it is constant, therefore, the constant square wave current of size of current in certain time and direction can be considered as direct current；Work as test
When what route flowed through is direct current, inductance is channel status to direct current in the circuit model of impedance ground, and there is no hinder to make
With at this moment the voltage measured on circuit model is the voltage of resistive component；Meanwhile what is flowed through when measurement circuit is direct current
When, it can be avoided generation Mutual Inductance Coupling phenomenon between measurement circuit, eliminate voltage error brought by Mutual Inductance Coupling phenomenon；It is based on
Test current and test voltage calculate the resistive component of Grounding impedance；Since voltage error is not present in test voltage, this
The resistive component that sample is calculated also will be not present error, improve the accuracy of resistive component；Also, the calculating of resistive component
Only it needs to be determined that the voltage generated on resistive component, does not need the phase angle of measurement impedance ground modulus value and impedance ground, greatly
Entire calculating process is simplified, computational efficiency is improved.
Fig. 6 shows a kind of resistive component measurement method of impedance ground provided in an embodiment of the present invention.It, should referring to Fig. 6
Method flow includes the following steps.
Step 201 applies test current to grounded screen.
Wherein, test current can be direct current, and test current is also possible to square wave current.The frequency of test current can be with
For 10Hz~60Hz.
Test current can be applied to grounded screen by power source and electric current pole.Specifically, the input terminal of power source with connect
Earth mat electrical connection, the output end of power source are electrically connected with electric current pole, and electric current pole is embedded in the earth.
Step 202 determines test voltage.
Wherein, test voltage is the voltage that test current generates on the resistive component of Grounding impedance.
When applying test current to grounded screen, test current can be measured by voltmeter in Grounding impedance
The voltage generated on resistive component.The input terminal of voltmeter is electrically connected with grounded screen, and output end and the voltage pole of voltmeter are electrically connected
It connects, voltage pole is embedded in the earth.
When test current is direct current, referring to fig. 2, inductance is channel status to direct current, and inhibition is not present, this
When, the voltage that voltmeter measurement obtains is the voltage that test current generates on the resistive component of Grounding impedance.
Square wave current can be unipolarity square wave current, and at this moment, the square wave current in half period is positive polarity DC
Electricity or negative polarity d. c electricity, in addition the square wave current in half period is 0.When test current is unipolarity square wave current
When, it is positive the half period of polarity DC electricity or negative polarity d. c electricity in square wave current, the electricity that voltmeter measurement obtains
Pressure is the voltage that test current generates on the resistive component of Grounding impedance.
In view of soil is under DC voltage effect, has polarity effect and generate polarization potential.When time of measuring is longer, pole
The influence of electrochemical potential accordingly enhances, and may cause measurement error to the test voltage of measurement.In order to solve the technical problem, at this
In embodiment, square wave current can also use bipolar square wave electric current, also, the duration of positive and negative polarity current is identical.This
When, the high level of square wave current is positive, and polarity DC is electric, and the low level of square wave current is negative polarity d. c electricity.Bipolar square wave electricity
Stream has the characteristics that alternating polarity and the single polarity duration is not grown, in this way, the polarization potential that soil generates also can be alternately anti-
It offsets, the influence to measurement can be ignored substantially, improve measurement accuracy.
When square wave current or bipolar square wave electric current, this step 202 includes the following steps 2021~step
2023。
Step 2021 determines the voltage that positive polarity electric current generates on resistive component.
Bipolar square wave electric current ISquare waveWaveform and the bipolar square wave function of current Fig. 2 shows circuit model on produce
Raw voltage USquare waveWaveform difference it is as shown in Figure 7.For time domain, due to the presence of inductance L, in positive square waves electric current
Under effect, the voltage U of circuit model generationSquare waveThe process that stable state is arrived in decline again, i.e. transient process and stable state mistake are increased to for step
Journey.Stabilization time is t1, and the duration that steady-state process to current polarity changes is t2.It is generated in transient process
Ceiling voltage and stabilization time t1 depending on the size of resistive component R in circuit model and induction reactance component L, are surveyed
Try the current changing rate di/dt of the corresponding Mutual Inductance Coupling M of line and square wave current.Current changing rate di/dt, refers to electric current
The slope for rising to amplitude from 0, for example it is 10 μ s that electric current rises to the time required to 1A from 0, then di/dt=1A/10 μ s=0.1A/
μs.In steady-state process, square wave current is after positive polarity reaches and stablizes, current changing rate di/dt=0, corresponding voltage magnitude
Size depends on the size of the resistance components R in circuit model, and unrelated with induction reactance component L.Also, Mutual Inductance Coupling M is not yet
Steady state voltage can be impacted.The electricity that polarity current generates on resistive component as it can be seen that the steady state voltage of steady-state process is positive
Pressure.In order to measure the steady state voltage in steady-state process, step 2021 may include steps of 2021a- step 2021c.
Step 2021a, in a cycle of square wave current, the voltage that positive polarity electric current generates in grounded screen is carried out
Continuous sampling.
In one timing of period of square wave current, the application time of positive polarity electric current is certain.In applying for positive polarity electric current
Between added-time, continuous sampling is carried out to the voltage that positive polarity electric current generates in grounded screen by voltmeter.It preferably, can be according to
Time interval carries out continuous sampling to the voltage that positive polarity electric current generates in grounded screen.Time interval can be according to square wave current
Period and required sampling number determine.
Step 2021b, the difference of two neighboring voltage in the voltage of sampling is determined.
The voltage of continuous sampling, is distributed sequentially in time.Step 2021b may include, sequentially in time, really
Surely the difference of two neighboring voltage in the voltage sampled.For example, determining the difference of the 1st voltage and the 2nd voltage, the 2nd is determined
The difference of a voltage and the 3rd voltage, and so on.
Step 2021c, it when the difference of two neighboring voltage is less than or equal to difference threshold, determines in two neighboring voltage
One of voltage is positive the voltage that polarity current generates on resistive component.
It is identical in the steady state voltage that the various time points measurement of steady-state process obtains.Based on this, if two are adjacent
The difference of the voltage at time point is equal to 0, it is determined that the voltage of two adjacent time points is steady state voltage.In view of in practical application
The interference of various factors, two adjacent steady state voltages can have fine error, therefore, a difference threshold can be set and come area
Divide the voltage in steady state voltage and transient process.Difference threshold can be an empirical value.In the present embodiment, difference threshold can
Think, the average value of the difference between each two neighboring voltage and the product of setting coefficient, setting coefficient can be 5%.
Specifically, step 2021c may include, firstly, determined in step 2021b two neighboring voltage difference it
Afterwards, the average value of each difference is calculated.Secondly, being based on mean value calculation difference threshold.Then, compare difference threshold and each difference
Value determines that one of voltage is positive polarity current in electricity in two neighboring voltage when difference is less than or equal to difference threshold
The voltage generated on resistance component.
Since transit time t1 is corresponding depending on the size of resistive component R and induction reactance component L, p-wire in circuit model
The current changing rate di/dt of Mutual Inductance Coupling M and square wave current, when in circuit model induction reactance component L or mutual inductance M it is larger
When, transit time t1 may be longer.In order to guarantee that voltmeter can measure steady state voltage, the half-wave week of square wave current can be extended
Phase reduces frequency, allows t1 transient process sufficiently to terminate, could obtain the accurate measurements of steady state voltage in steady state time t2.Base
In this, the frequency of square wave current can be 45Hz~55Hz.The frequency of square wave current can be configured by power source.
Step 2022 determines the voltage that negative polarity electric current generates on resistive component.
Step 2022 may include, and in a cycle of square wave current, generate in grounded screen to negative polarity electric current
Voltage carries out continuous sampling；Determine the difference of two neighboring voltage in the voltage of sampling；When the difference of two neighboring voltage is less than
Or when being equal to difference threshold, determine that one of voltage is negative what polarity current generated on resistive component in two neighboring voltage
Voltage.
The specific implementation process of step 2022 can produce on resistive component according to positive polarity electric current determining in step 2021
The mode of raw voltage determines the voltage that negative polarity electric current generates on resistive component, and details are not described herein.
Step 2023, the voltage generated on resistive component based on positive polarity electric current and negative polarity electric current are in resistance point
The voltage generated in amount calculates test voltage.
It can be according to formula USquare wave=(| UPositive polarity|+|UNegative polarity|)/2 calculating test voltages, USquare waveFor test voltage, UPositive polarityIt is positive
The voltage that polarity current generates on resistive component, UNegative polarityThe voltage that the polarity current that is negative generates on resistive component.
Under an alternating polarity period of square wave current, test voltage and circuit model that voltmeter measurement obtains
In resistive component R it is related, it is unrelated with induction reactance component L and mutual inductance component M, thus ensure that impedance ground resistive component survey
Amount is not influenced by Mutual Inductance Coupling.
Step 203 is based on test current and test voltage, calculates the resistive component of Grounding impedance.
It can be according to formula R=USquare wave/ISquare waveCalculate the resistive component R of Grounding impedance.
Fig. 8 shows a kind of grid grounding impedance measurement method provided in an embodiment of the present invention, and referring to Fig. 8, this method includes such as
Lower process.
Step 301 applies the first test current to grounded screen.
Wherein, the first test current is direct current or square wave current.The frequency of first test current can for 40Hz~
60Hz。
Step 302 determines the first test voltage.
Wherein, the first test voltage is the electricity that the first test current generates on the resistive component of Grounding impedance
Pressure.
Step 303 is based on the first test current and the first test voltage, calculates the resistive component of Grounding impedance.
Step 301~step 303 is respectively with step 101~step 103 in the embodiment shown in Fig. 5, and details are not described herein.
Step 304 applies the second test current to grounded screen.
Wherein, the second test current is sine-wave current, and the frequency of the second test current can be 10Hz~60Hz.
Step 305 determines the second test voltage.
Wherein, the second test voltage is the voltage that the second test current generates in grounded screen.
Step 306 is based on the second test current and the second test voltage, calculates the modulus value of impedance ground.
Step 307, the modulus value based on resistive component and impedance ground, calculate the phase angle of impedance ground.
It can be based on formula R=| Z | cos θ calculates the phase angle of impedance ground, and R is the resistive component of impedance ground, | Z | be
The modulus value of impedance ground, θ are phase angle.
The modulus value of step 308, the phase angle based on impedance ground and impedance ground calculates impedance ground.
It can be based on formula Z=| Z | ∠ θ calculates impedance ground, and Z is impedance ground.
Then the embodiment of the present invention is determined by applying the first test current, i.e. direct current or square wave current to grounded screen
The voltage that direct current or square wave current generate on the resistive component of Grounding impedance；Due to the square wave electricity in certain time
The size of current of stream and direction be it is constant, therefore, square wave current that can be constant by size of current in certain time and direction
It is considered as direct current；When measurement circuit flow through be direct current when, inductance is access to direct current in the circuit model of impedance ground
Inhibition is not present in state, and at this moment the first test voltage measured on circuit model is the voltage of resistive component；Together
When, when measurement circuit flow through be direct current when, can be avoided between measurement circuit generation Mutual Inductance Coupling phenomenon, eliminate mutual inductance coupling
Close voltage error brought by phenomenon；Based on the first test current and the first test voltage, the electricity of Grounding impedance is calculated
Hinder component；Since voltage error is not present in the first test voltage, the resistive component being calculated so also will be not present error, mention
The high accuracy of resistive component；After the modulus value for calculating impedance ground, the modulus value based on resistive component and impedance ground, meter
The phase angle for calculating impedance ground, since resistive component is obtained in the case of eliminating voltage error brought by Mutual Inductance Coupling phenomenon
, accuracy is higher, therefore the phase angle accuracy of impedance ground is also relatively high；Phase angle and impedance ground based on impedance ground again
Modulus value, calculate impedance ground, since the accuracy of resistive component and the phase angle of impedance ground is higher, obtained impedance ground
Accuracy it is also relatively high.
Fig. 9 shows a kind of grid grounding impedance measurement method provided in an embodiment of the present invention, and referring to Fig. 9, this method includes such as
Lower process.
Step 401 applies the first test current to grounded screen.
As optional embodiment, the first test current is square wave current.The frequency of first test current can be
10Hz~60Hz.Preferably, the frequency of the first test current can be 45Hz~55Hz.
Step 402 determines the first test voltage.
As optional embodiment, square wave current is bipolar square wave electric current, when the first test current is square wave current
When, step 402 may include steps of 4021~step 4023.
Step 4021 determines the voltage that positive polarity electric current generates on resistive component.
Step 4022 determines the voltage that negative polarity electric current generates on resistive component.
Step 4023, the voltage generated on resistive component based on positive polarity electric current and negative polarity electric current are in resistance point
The voltage generated in amount calculates the first test voltage.
Step 4021~step 4023 can with step 2021~step 2023 in the embodiment shown in Fig. 6, herein no longer
It repeats.
Step 403 is based on the first test current and the first test voltage, calculates the resistive component of Grounding impedance.
The content of not detailed description refers to step 201~step in the embodiment shown in Fig. 6 in step 401~step 403
Rapid 203, details are not described herein.
Step 404 applies the second test current to grounded screen.
Wherein it is possible to apply the second test current to grounded screen by power source and electric current pole.Second test current is positive
String wave electric current, the frequency of sine-wave current can be 50Hz, be also possible to than close but different from the frequency of 50Hz, include but not office
It is limited to 10~60Hz, and the frequency of sine-wave current can be configured by power source.Preferably, second test current
Frequency can be 45Hz~55Hz.
Step 405 determines the second test voltage.
Wherein it is possible to measure the second test voltage by voltmeter and voltage pole, the second test voltage is the second test electricity
Flow the voltage generated in grounded screen.
Step 406 is based on the second test current and the second test voltage, calculates the modulus value of impedance ground.
Second test current ISine waveWith the second test voltage USine waveWaveform it is as shown in Figure 10.In the effect of sine-wave current
Under, the voltage U at circuit model both endsSine waveIts amplitude depends on the impedance magnitude of circuit model.Moreover, when there is Mutual Inductance Coupling at scene
When M, the voltage that voltage pole measurement obtains also can be impacted.The voltmeter measurement electricity that voltage pole is presented under sine-wave current effect
Pressure.The modulus value of the impedance ground of grounded screen | Z |=USine wave/ISine wave, USine waveFor the second test voltage, ISine waveFor the second test electricity
Stream.
Step 407, the modulus value based on resistive component and impedance ground, calculate the phase angle of impedance ground.
It can be based on formula R=| Z | cos θ calculates the phase angle of impedance ground, and R is the resistive component of impedance ground, | Z | be
The modulus value of impedance ground, θ are phase angle.
The modulus value of step 408, the phase angle based on impedance ground and impedance ground calculates impedance ground.
It can be based on formula Z=| Z | ∠ θ calculates impedance ground, and Z is impedance ground.
The phase angle of step 409, the modulus value based on impedance ground and impedance ground calculates the induction reactance component of impedance ground.
The induction reactance component of impedance ground is impedance ground imaginary part X, and what is reacted is the self-induction induction reactance L of grounded screen, size
It will affect transient overvoltage when fault transient state current or lightning stroke high-frequency current injection earth mat.Therefore electric system can pay close attention to ground connection
The induction reactance component of impedance.It can be based on formulaOr X=| Z | the induction reactance component X of sin θ calculating impedance ground.
Step 410 determines the corresponding frequency of impedance ground, the induction reactance based on the corresponding frequency of impedance ground and impedance ground
Component calculates the self-induction component of impedance ground.
Self-induction the component L, f that impedance ground can be calculated based on formula L=X/2 π f are the corresponding frequency of impedance ground.When
When impedance ground is power-frequency earthing impedance, the corresponding frequency f of impedance ground is 50Hz.
Power source first sends the first test current I of alternation direct currentSquare wave, and continue for some time tSquare wave, surveyed by voltmeter
The first test voltage U that one test current of flow control generatesSquare wave, the resistive component R of impedance ground is calculated by ohm law.Function
Rate source retransmits the second test current ISine wave, and continue for some time tSine wave, the second test current is measured by voltmeter and is generated
The second test voltage USine wave, impedance ground modulus value is calculated by ohm law | Z |.Finally based on R and | Z | the two independences
Measurement parameter calculates induction reactance component (i.e. imaginary part) X, self-induction induction reactance L and the phase angle theta of impedance ground.
The duration t of first test currentSquare waveThe period of several square wave currents is generally required, to guarantee to obtain one
More stable voltage measuring value.From the point of view of experience, tSquare waveDuration can be 3-5 seconds.Likewise, more stable in order to obtain
Sine-wave current effect under voltage measuring value, tSine waveDuration is also possible to 3-5 seconds.
In the application, power source and voltmeter are either independent unit, also can integrate the tester for integral type.
Figure 11 shows the resistive component measuring device or ground connection resistance of a kind of impedance ground provided in an embodiment of the present invention
Anti- measuring device.Specifically, measuring device 1800 includes central processing unit (CPU) 1801 including random access memory
The system storage 1804 of device (RAM) 1802 and read-only memory (ROM) 1803, and connection system storage 1804 and center
The system bus 1805 of processing unit 1801.
Without loss of generality, computer-readable medium may include computer storage media and communication media.Computer storage
Medium includes any of the information such as computer readable instructions, data structure, program module or other data for storage
The volatile and non-volatile of method or technique realization, removable and irremovable medium.Computer storage medium include RAM,
ROM, EPROM, EEPROM, flash memory or other solid-state storages its technologies, CD-ROM, DVD or other optical storages, cassette, magnetic
Band, disk storage or other magnetic storage devices.Certainly, skilled person will appreciate that computer storage medium is not limited to
It states several.
Above-mentioned memory further includes one, and perhaps more than one program one or more than one program are stored in storage
In device, it is configured to be executed by CPU 1801.When CPU 1801 executes the program in memory, aforementioned impedance ground may be implemented
Measurement method or impedance ground resistive component measurement method performed by step.
In the exemplary embodiment, a kind of computer readable storage medium including instruction is additionally provided, for example including finger
The memory of order, above-metioned instruction can be loaded by the central processing unit 1801 of measuring device 1800 and be executed to complete aforementioned ground connection
Step performed by measuring device in the measurement method of the resistive component of the measurement method or impedance ground of impedance.For example, meter
Calculation machine readable storage medium storing program for executing can be ROM, random access memory (RAM), CD-ROM, tape, floppy disk and optical data storage and set
It is standby etc..
It should be understood that the resistive component measuring device of impedance ground provided by the above embodiment is in measurement impedance ground
Resistive component when, only the example of the division of the above functional modules, in practical application, can according to need and incite somebody to action
Above-mentioned function distribution is completed by different functional modules, i.e., the internal structure of equipment is divided into different functional modules, with complete
At all or part of function described above.In addition, the resistive component measuring device of impedance ground provided by the above embodiment
Belonging to same design with the resistive component measurement method embodiment of impedance ground, specific implementation process is detailed in embodiment of the method,
Which is not described herein again.Footing impedance measuring apparatus provided by the above embodiment is when measuring impedance ground, only with above-mentioned each function
The division progress of module can according to need and for example, in practical application by above-mentioned function distribution by different function moulds
Block is completed, i.e., the internal structure of equipment is divided into different functional modules, to complete all or part of function described above
Energy.In addition, footing impedance measuring apparatus provided by the above embodiment and grid grounding impedance measurement embodiment of the method belong to same design,
Its specific implementation process is detailed in embodiment of the method, and which is not described herein again.
Figure 12 shows a kind of earth loop impedance test instrument provided in an embodiment of the present invention, referring to Figure 12, earth loop impedance test
Instrument includes: power source 501, voltmeter 502 and footing impedance measuring apparatus 503.
Footing impedance measuring apparatus 503 is used for, and applies the first test current, the first examination to grounded screen by power source 501
Galvanoscope is direct current or square wave current；Determine that the first test voltage, the first test voltage are the first test by voltmeter 502
The voltage that electric current generates on the resistive component of Grounding impedance；Based on the first test current and the first test voltage, meter
Calculate the resistive component of Grounding impedance；Apply the second test current, the second test current to grounded screen by power source 501
For sine-wave current, the frequency of the frequency of the first test current and the second test current is 10Hz~60Hz；Pass through voltmeter
True 502 fixed second test voltages, the second test voltage are the voltage that the second test current generates in grounded screen；Based on the second examination
Galvanoscope and the second test voltage, calculate the modulus value of impedance ground；Modulus value based on resistive component and impedance ground calculates ground connection
The phase angle of impedance；The modulus value of phase angle and impedance ground based on impedance ground calculates impedance ground.
The footing impedance measuring apparatus 503 can be the measuring device shown in Figure 11.
Then the embodiment of the present invention is determined by applying the first test current, i.e. direct current or square wave current to grounded screen
The voltage that direct current or square wave current generate on the resistive component of Grounding impedance；Due to the square wave electricity in certain time
The size of current of stream and direction be it is constant, therefore, square wave current that can be constant by size of current in certain time and direction
It is considered as direct current；When measurement circuit flow through be direct current when, inductance is access to direct current in the circuit model of impedance ground
Inhibition is not present in state, and at this moment the first test voltage measured on circuit model is the voltage of resistive component；Together
When, when measurement circuit flow through be direct current when, can be avoided between measurement circuit generation Mutual Inductance Coupling phenomenon, eliminate mutual inductance coupling
Close voltage error brought by phenomenon；Based on the first test current and the first test voltage, the electricity of Grounding impedance is calculated
Hinder component；Since voltage error is not present in the first test voltage, the resistive component being calculated so also will be not present error, mention
The high accuracy of resistive component；After the modulus value for calculating impedance ground, the modulus value based on resistive component and impedance ground, meter
The phase angle for calculating impedance ground, since resistive component is obtained in the case of eliminating voltage error brought by Mutual Inductance Coupling phenomenon
, accuracy is higher, therefore the phase angle accuracy of impedance ground is also relatively high；Phase angle and impedance ground based on impedance ground again
Modulus value, calculate impedance ground, since the accuracy of resistive component and the phase angle of impedance ground is higher, obtained impedance ground
Accuracy it is also relatively high.
Those of ordinary skill in the art will appreciate that realizing that all or part of the steps of above-described embodiment can pass through hardware
It completes, relevant hardware can also be instructed to complete by program, the program can store in a kind of computer-readable
In storage medium, storage medium mentioned above can be read-only memory, disk or CD etc..
The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and
Within principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.
Claims (10)
1. a kind of grid grounding impedance measurement method, which is characterized in that the described method includes:
Apply the first test current to grounded screen, first test current is direct current or square wave current；
Determine that the first test voltage, first test voltage are first test current in the Grounding impedance
The voltage generated on resistive component；
Based on first test current and first test voltage, the resistive component of the Grounding impedance is calculated；
Apply the second test current to the grounded screen, second test current is sine-wave current, the first test electricity
The frequency of stream and the frequency of second test current are 10Hz~60Hz；
Determine that the second test voltage, second test voltage are the electricity that second test current generates in the grounded screen
Pressure；
Based on second test current and second test voltage, the modulus value of the impedance ground is calculated；
Modulus value based on the resistive component and the impedance ground, calculates the phase angle of the impedance ground；
The modulus value of phase angle and the impedance ground based on the impedance ground, calculates the impedance ground.
2. the method according to claim 1, wherein the square wave current is bipolar square wave electric current, when described
When first test current is the square wave current, first test voltage of determination, comprising:
Determine the voltage that positive polarity electric current generates on the resistive component；
Determine the voltage that negative polarity electric current generates on the resistive component；
The voltage and the negative polarity electric current generated on the resistive component based on the positive polarity electric current is in the resistance
The voltage generated on component calculates first test voltage.
3. the method according to claim 1, wherein the method also includes:
Modulus value based on the resistive component and the impedance ground calculates the induction reactance component of the impedance ground.
4. a kind of resistive component measurement method of impedance ground, which is characterized in that the described method includes:
Apply test current to grounded screen, the test current is direct current or square wave current, and the frequency of the test current is
10Hz~60Hz；
Determine that test voltage, the test voltage are that the test current produces on the resistive component of the Grounding impedance
Raw voltage；
Based on the test current and the test voltage, the resistive component of the Grounding impedance is calculated.
5. according to the method described in claim 4, it is characterized in that, the square wave current is bipolar square wave electric current, when described
When test current is the square wave current, the determining test voltage, comprising:
Determine the voltage that positive polarity electric current generates on the resistive component；
Determine the voltage that negative polarity electric current generates on the resistive component；
The voltage and the negative polarity electric current generated on the resistive component based on the positive polarity electric current is in the resistance
The voltage generated on component calculates the test voltage.
6. according to the method described in claim 5, it is characterized in that, the determining positive polarity electric current produces on the resistive component
Raw voltage, comprising:
In a cycle of the square wave current, the voltage generated in the grounded screen to the positive polarity electric current connects
Continuous sampling；
Determine the difference of two neighboring voltage in the voltage of sampling；
When the difference of the two neighboring voltage is less than or equal to difference threshold, wherein one is determined in the two neighboring voltage
A voltage is the voltage that the positive polarity electric current generates on the resistive component.
7. according to the method described in claim 5, it is characterized in that, the frequency of the test current is 45Hz~55Hz.
8. a kind of footing impedance measuring apparatus, which is characterized in that described device includes processor and memory, in the memory
It is stored at least one instruction, described instruction is loaded by the processor and executed to realize such as any one of claim 1-3
Operation performed by the grid grounding impedance measurement method.
9. a kind of earth loop impedance test instrument, which is characterized in that the earth loop impedance test instrument includes:
Power source, voltmeter and footing impedance measuring apparatus；
The footing impedance measuring apparatus is used for, by the power source to grounded screen apply the first test current, described first
Test current is direct current or square wave current；Determine that the first test voltage, first test voltage are by the voltmeter
The voltage that first test current generates on the resistive component of the Grounding impedance；Based on the first test electricity
Stream and first test voltage, calculate the resistive component of the Grounding impedance；It is connect by the power source to described
Earth mat applies the second test current, and second test current is sine-wave current, the frequency of first test current and institute
The frequency for stating the second test current is 10Hz~60Hz；The second test voltage, second examination are determined by the voltmeter
Electrical verification pressure is the voltage that second test current generates in the grounded screen；Based on second test current and described
Two test voltages calculate the modulus value of the impedance ground；Modulus value based on the resistive component and the impedance ground calculates institute
State the phase angle of impedance ground；The modulus value of phase angle and the impedance ground based on the impedance ground, calculates the impedance ground.
10. a kind of resistive component measuring device of impedance ground, which is characterized in that described device includes processor and memory,
At least one instruction is stored in the memory, described instruction is loaded by the processor and executed to realize such as claim
Operation performed by the resistive component measurement method of impedance ground described in any one of 4-7.
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