CN112305351A - MOA resistive current measuring method for leakage current reconstruction voltage - Google Patents

MOA resistive current measuring method for leakage current reconstruction voltage Download PDF

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CN112305351A
CN112305351A CN202011125246.3A CN202011125246A CN112305351A CN 112305351 A CN112305351 A CN 112305351A CN 202011125246 A CN202011125246 A CN 202011125246A CN 112305351 A CN112305351 A CN 112305351A
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moa
phase
current
data
voltage
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钱国超
潘浩
彭庆军
周仿荣
马御棠
马仪
黄然
文刚
耿浩
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
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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
    • G01R31/003—Environmental or reliability tests
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • 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
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
    • G01R31/1236—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of surge arresters
    • 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
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
    • 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
    • G01R31/52—Testing for short-circuits, leakage current or ground faults

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Abstract

The application provides an MOA resistive current measuring method for reconstructing voltage by leakage current, which comprises the following steps: obtaining a current signal I of an MOA grounding down lead to be testedXThe current signal I of the in-phase capacitive equipment grounding down lead; MOA data K obtained by linear transformation1IXAnd in-phase capacitive device data K2I; performing analog-to-digital conversion to obtain digital quantity, and performing Fourier transform; extracting fundamental wave angle phi in MOA result after Fourier transformXAnd fundamental angle Φ in-phase capacitive device results; phase comparison is carried out to obtain an equivalent dielectric loss angle theta of the lightning arrester;obtaining the resistive current I of the lightning arresterR＝IXX sin θ. The method has the advantages that the resistive current of the zinc oxide arrester in the power grid can be quickly and accurately acquired, the operation is simple and safe, reliable guarantee can be provided for performance evaluation of the zinc oxide arrester, safety of power equipment and the like, technical support is provided for safe and reliable operation and modification decision of the power system, the MOA voltage to be measured is obtained by adopting a voltage-transformer-free measuring mode, the action of a protection device is avoided, and the safety of the power system is improved.

Description

MOA resistive current measuring method for leakage current reconstruction voltage
Technical Field
The application relates to the field of online detection, in particular to an MOA resistive current measuring method for reconstructing voltage by leakage current.
Background
The insulating state of a Metal Oxide Arrester (MOA) is important for safe operation of itself and surrounding electrical equipment.
The traditional measuring method comprises a secondary voltage method, an induction plate method and a compensation method; the secondary voltage method is characterized in that a voltage transformer is used for obtaining the voltage of the MOA to be detected, meanwhile, the leakage current of the arrester is synchronously collected, the resistive current component of the MOA is extracted through an algorithm, and when a voltage signal is obtained at a secondary terminal of the voltage transformer, the situations of short circuit and the like of a secondary circuit exist; the method comprises the following steps that an induction plate method obtains MOA voltage to be measured through a non-contact sensor in an MOA resistive current measuring mode without voltage reference, the working principle of the method is that a capacitive voltage divider is formed by stray capacitance existing between a power transmission line and the sensor and voltage dividing capacitance of the sensor, so that voltage waveform in the power transmission line is obtained, and an induction metal plate leads out a voltage signal through a matching resistor and transmits the voltage signal to an external data acquisition system through a coaxial cable; the compensation method is based on the principle that the sum of total leakage currents of the zinc oxide arresters which are three phases of each other is the third harmonic component of the resistive current component, and the aging degree of the arrester is reflected by the third harmonic component of the resistive current.
However, the secondary terminal of the voltage transformer is also connected with the protection device, and the situation of a secondary loop short-circuit lamp occurs, which may cause the action of the power grid protection device, and bring the safety hazard of the power system device and the reduction of the electric energy transmission stability, and the stray capacitance between the power transmission line and the sensor is seriously influenced by the external interference, which may cause the reduction of the precision.
Disclosure of Invention
The application provides a MOA resistive current measuring method for reconstructing voltage by leakage current, which aims to solve the technical problem that a secondary terminal of a voltage transformer is still connected with a protection device, the situation of a secondary loop short-circuit lamp occurs, the action of a power grid protection device can be caused, the safety hazard of power system equipment and the reduction of electric energy transmission stability are brought, stray capacitance between a power transmission line and a sensor is seriously influenced by external interference, the precision is reduced, a harmonic analysis method has harsh preconditions and is influenced by MOA voltage triple harmonic to be detected, and the technical problem that the change of a resistive current component is caused by which phase is difficult to judge.
In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions:
an MOA resistive current measuring method for reconstructing voltage by leakage current is provided, and the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXThe current signal I of the in-phase capacitive equipment grounding down lead;
the current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the in-phase capacitive equipment grounding down lead obtains MOA data K to be measured through linear transformation1IXAnd in-phase capacitive device data K2I；
The MOA data K to be tested1IXAnd said in-phase capacitive device data K2I, performing analog-to-digital conversion on the digital value, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental angle Φ in-phase capacitive device results;
the fundamental wave angle phiXComparing the phase with the fundamental wave angle phi to obtain an equivalent dielectric loss angle theta of the lightning arrester;
calculating the resistive current I of the lightning arresterR＝IX×sinθ。
Further according to the formula
Figure BDA0002733396240000021
And performing reverse pushing on the current integral of the in-phase capacitive equipment grounding down lead to obtain the MOA voltage to be measured.
In one possible implementation, the in-phase capacitive device is an in-phase high voltage capacitor; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of grounding down lead of in-phase high-voltage capacitorC；
The current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the in-phase high-voltage capacitor grounding down leadCObtaining MOA data K to be measured through linear transformation1IXAnd in-phase high voltage capacitor data K2IC；
The MOA data K to be tested1IXAnd said in-phase high voltage capacitor data K2ICPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd is in phase highFundamental angle phi in piezoelectric capsule resultsC；
The fundamental wave angle phiXAnd the fundamental wave angle phiCPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterC；
Calculating the resistive current I of the lightning arresterRC＝IX×sinθC。
Further, the measurement method further includes:
according to the formula
Figure BDA0002733396240000022
And performing reverse pushing on the current integral of the in-phase high-voltage capacitor grounding down lead to obtain the MOA voltage to be measured.
In one possible implementation, the in-phase capacitive device is an in-phase current transformer; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of grounding down lead of in-phase current transformerTA；
The current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the grounding down lead of the in-phase current transformerTAObtaining MOA data K to be measured through linear transformation1IXAnd in-phase current transformer data K2ITA；
The MOA data K to be tested1IXAnd said in-phase current transformer data K2ITAPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental angle phi in-phase current transformer resultTA；
The fundamental wave angle phiXAnd the fundamental wave angle phiTAPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterTA；
Calculating the resistive current I of the lightning arresterRTA＝IX×sinθTA。
Further, the measurement method further includes:
according to the formula
Figure BDA0002733396240000031
And performing reverse pushing on the current integral of the grounding down lead of the in-phase current transformer to obtain the MOA voltage to be measured.
In one possible implementation manner, the in-phase capacitive device is an in-phase main transformer bushing; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of end screen of high-voltage bushing of in-phase main transformerT；
The current signal I of the MOA to be tested grounding down leadXAnd a current signal I of a high-voltage bushing end screen of the in-phase main transformerTLinear conversion is carried out through a signal amplifier to obtain MOA data K to be measured1IXAnd in-phase main transformation data K2IT；
The MOA data K to be tested1IXAnd said in-phase main transformer casing data K2ITPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental wave angle phi in-phase main transformation resultT；
The fundamental wave angle phiXAnd the fundamental wave angle phiTPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterT；
Calculating the resistive current I of the lightning arresterRT＝IX×sinθT。
Further, the measurement method further includes:
according to the formula
Figure BDA0002733396240000032
And performing reverse thrust on the current integral of the end screen of the in-phase main transformer high-voltage bushing to obtain the MOA voltage to be measured.
The application provides an MOA resistive current measuring method for reconstructing voltage by leakage current, which comprises the following steps: obtaining a current signal I of an MOA grounding down lead to be testedXThe current signal I of the in-phase capacitive equipment grounding down lead; MOA data K obtained by linear transformation1IXAnd in-phase capacitive device data K2I; performing analog-to-digital conversion to obtain digital quantity, and performing Fourier transform; extracting fundamental wave angle phi in MOA result after Fourier transformXAnd fundamental angle Φ in-phase capacitive device results; phase comparison is carried out to obtain an equivalent dielectric loss angle theta of the lightning arrester; obtaining the resistive current I of the lightning arresterR＝IXX sin θ. The method has the advantages that the resistive current of the zinc oxide arrester in the power grid can be quickly and accurately acquired, the operation is simple and safe, reliable guarantee can be provided for performance evaluation of the zinc oxide arrester, safety of power equipment and the like, technical support is provided for safe and reliable operation and modification decision of the power system, the MOA voltage to be measured is obtained by adopting a voltage-transformer-free measuring mode, the action of a protection device is avoided, and the safety of the power system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a wave point method of a harmonic analysis method in the prior art of the present application;
fig. 2 is a schematic flowchart of an MOA resistive current measurement method for reconstructing voltage by using leakage current according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of an MOA resistive current measurement method based on in-phase high-voltage capacitor leakage current reconstructed voltage according to an embodiment of the present application;
fig. 4 is a schematic diagram of an MOA resistive current measurement method based on in-phase current transformer leakage current reconstruction voltage according to an embodiment of the present application;
fig. 5 is a schematic diagram of an MOA resistive current measurement method based on in-phase main transformer leakage current reconstructed voltage according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a vector phase relationship according to an embodiment of the present application;
wherein: 1-MOA to be detected; 11-an MOA to be tested grounding down lead; 21-a first current sensor; 22-a second current sensor; 23-a third current sensor; 24-a fourth current sensor; 3-high pressure pipe bus; 4-in-phase high voltage capacitor; 41-the in-phase high-voltage capacitor grounding down lead; 5-in-phase current transformer; 51-grounding down lead of in-phase current transformer; 6-cophase main transformer; and 61-in-phase main transformer high-voltage bushing end screen.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The existing measuring method also reflects the aging degree of the arrester by utilizing the third harmonic component of the resistive current according to the principle that the sum of the total leakage currents of the zinc oxide arresters which are three phases mutually is the third harmonic component of the resistive current component, but the harmonic analysis method has harsh precondition, is influenced by the third harmonic of the MOA voltage to be measured, and is difficult to judge which phase the change of the resistive current component is caused by.
According to the harmonic analysis method, according to the characteristic of trigonometric function orthogonality, the harmonic analysis method sequentially carries out orthogonal processing on the total leakage current and each subharmonic of the excitation voltage, and therefore the amplitude and the phase of each subharmonic component of the resistive current component of the zinc oxide arrester are obtained. The resistive current extraction method has large calculation amount and is less influenced by voltage harmonics.
When the excitation voltage and the total leakage current waveforms are symmetrical about 90 °, as shown in fig. 1 by the wave point method, the resistive current component can be obtained by the sum of two total leakage currents that are symmetrical points to each other, at t1And t2The relationship between the total leakage current at the time and the resistive and capacitive current components is expressed as:
i(t1)＝iR(t1)+iC(t1)
i(t2)＝iR(t2)+iC(t2)
in the formula, i (t)1)、i(t2) Are each t1And t2Total leakage current at time iR(t1)、iR(t2) Are each t1And t2Resistive current component of time, iC(t1)、iC(t2) Are each t1And t2Capacitive current component at a time.
When the excitation voltage and the total leakage current waveform are symmetric about 90 °, the capacitive current components at two points of symmetry are opposite and the resistive current components are the same, and are expressed as:
iC(t1)＝-iC(t2)
iR(t1)＝iR(t2)
to obtain t1And t2The resistive current component at a time is
Figure BDA0002733396240000051
The principle of the method is simple, but the method is only suitable for the situation that the excitation voltage and the total leakage current waveform are symmetrical about 90 degrees, and when the excitation voltage contains harmonics, the error of the method is large.
The present application is described in further detail below with reference to the attached drawing figures:
the embodiment of the application provides an MOA resistive current measuring method for reconstructing voltage by leakage current, an MOA to be measured and an in-phase capacitive device are both connected with a high-voltage tube bus 3, as shown in fig. 2, the measuring method comprises the following steps:
s100, respectively acquiring current signals I of the MOA grounding down lead to be detected through two current sensorsXAnd a current signal I of the in-phase capacitive equipment grounding down lead. For the leakage current of the MOA, the leakage current has the characteristics of small amplitude but larger equivalent dielectric loss angle; according to the scheme, the secondary output voltage of the voltage transformer is not acquired as a reference, and the protection misoperation risk caused by the short circuit of a secondary system due to misoperation is avoided.
S200, current signal I of grounding down lead of MOA to be testedXAnd the current signal I of the in-phase capacitive equipment grounding down lead is linearly converted through a signal amplifier to obtain MOA data K to be measured1IXAnd in-phase capacitive device data K2I。
S300, the MOA data K to be detected1IXAnd said in-phase capacitive device data K2I is converted into digital quantity through analog-digital conversion, and the digital quantity is subjected to Fourier transform.
S400, extracting a fundamental wave phase after Fourier transformation to obtain a fundamental wave angle phi in an MOA result to be detectedXAnd fundamental angle phi in-phase capacitive device results.
S500, converting the fundamental wave angle phiXAnd comparing the phase with the fundamental wave angle phi to obtain the equivalent dielectric loss angle theta of the lightning arrester.
S600, obtaining the resistive current I of the lightning arresterR＝IX×sinθ。
Fig. 6 is a schematic diagram showing the phase relationship of the parameters. Because the capacitor is pure capacitive equipment, the dielectric loss of the capacitor is zero, and the current I of the in-phase capacitive equipment grounding down lead is integrated by utilizing an integrating circuit, so that the system voltage U can be obtained, and the measuring method of the embodiment further comprises the following steps: according to the formula
Figure BDA0002733396240000061
And performing reverse pushing on the current integral of the in-phase capacitive equipment grounding down lead to obtain the MOA voltage to be measured.
In one embodiment, as shown in fig. 3, the in-phase capacitive device is an in-phase high voltage capacitor 4; at this time, the measuring method includes the steps of:
acquiring a current signal I of the MOA1 to be measured grounding down-lead 11 through the first current sensor 21 and the second current sensor 22XCurrent signal I of the in-phase high-voltage capacitor ground down-lead 41C。
The current signal I of the down lead 11 is connected with the ground of the MOA1 to be testedXAnd the current signal I of the in-phase high-voltage capacitor ground down-lead 41CLinear conversion is carried out through a signal amplifier to obtain MOA1 data K to be measured1IXAnd in-phase high-voltage capacitor 4 data K2IC；
The MOA1 data K to be tested1IXAnd said in-phase high-voltage capacitor 4 data K2ICPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA1 result to be detected after Fourier transformationXAnd fundamental angle phi in result of in-phase high-voltage capacitor 4C；
The fundamental wave angle phiXAnd the fundamental wave angle phiCPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterC；
Calculating the resistive current I of the lightning arresterRC＝IX×sinθC。
The MOA voltage technology to be measured by reconstructing leakage current of the same-bus, same-voltage grade and same-phase high-voltage capacitor 4 corresponding to the arrester is applied to the live detection of the zinc oxide arrester, so that the operation safety index of the arrester resistive current measurement is improved;
the measurement method further comprises:
according to the formula
Figure BDA0002733396240000062
And performing reverse pushing on the current integral of the in-phase high-voltage capacitor grounding down lead to obtain the MOA voltage to be measured. Because the capacitance of the capacitor is large, the dielectric loss tangent value is less than 0.1%, the corresponding dielectric loss angle is also extremely small and is far less than the equivalent dielectric loss angle of the zinc oxide arrester. Therefore, the capacitor is considered to be a pure capacitive device, and the capacitive current leads the capacitive voltage by 90 degrees.
As shown in fig. 4, in one embodiment, the in-phase capacitive device is an in-phase current transformer 5; at this time, the measuring method includes the steps of:
acquiring a current signal I of the MOA1 to be measured grounding down-lead 11 through the first current sensor 21 and the third current sensor 23XCurrent signal I of grounding down lead 51 of in-phase current transformerTA；
The current signal I of the down lead 11 is connected with the ground of the MOA1 to be testedXAnd the current signal I of the in-phase current transformer grounding down lead 51TALinear conversion is carried out through a signal amplifier to obtain MOA1 data K to be measured1IXAnd in-phase current transformer 5 data K2ITA；
The MOA1 data K to be tested1IXAnd said in-phase current transformer 5 data K2ITAPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA1 result to be detected after Fourier transformationXAnd fundamental angle phi in result of in-phase current transformer 5TA；
The fundamental wave angle phiXAnd the fundamental wave angle phiTAPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterTA；
Calculating the resistive current I of the lightning arresterRTA＝IX×sinθTA。
The MOA voltage technology for reconstructing the leakage current of the same-bus, same-voltage grade and same-phase current transformer 5 corresponding to the arrester to be detected is applied to the live detection of the zinc oxide arrester, so that the operation safety index of the arrester resistive current measurement is improved.
The measurement method further comprises:
according to the formula
Figure BDA0002733396240000071
And performing reverse pushing on the current integral of the grounding down lead of the in-phase current transformer to obtain the MOA voltage to be measured. Because the capacitance of the high-voltage end of the current transformer to the ground is large, the tangent value of the dielectric loss angle is less than 0.1 percent, the corresponding dielectric loss angle is extremely small, and is far less than the equivalent dielectric loss angle of the zinc oxide arrester. The current transformer leakage current ITA is therefore considered to lead the bus voltage by 90 degrees.
As shown in fig. 5, in one embodiment, the in-phase capacitive device is an in-phase main transformer bushing 6; at this time, the measuring method includes the steps of:
acquiring a current signal I of the MOA1 to be measured grounding down-lead 11 through the first current sensor 21 and the fourth current sensor 24XCurrent signal I of high-voltage bushing end screen 61 of in-phase main transformerT；
The current signal I of the down lead 11 is connected with the ground of the MOA1 to be testedXAnd the current signal I of the end screen 61 of the in-phase main transformer high-voltage bushingTLinear conversion is carried out through a signal amplifier to obtain MOA1 data K to be measured1IXAnd in-phase main transformer 6 data K2IT；
The MOA1 data K to be tested1IXAnd said in-phase main transformer 6 data K2ITPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA1 result to be detected after Fourier transformationXAnd fundamental wave angle phi in-phase main transformer 6 resultT；
The fundamental wave angle phiXAnd the fundamental wave angle phiTPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterT；
Calculating the resistive current I of the lightning arresterRT＝IX×sinθT。
The MOA voltage technology to be measured by reconstructing the leakage current of the same-bus, same-voltage grade and same-phase main transformer bushing 6 corresponding to the arrester is applied to the live detection of the zinc oxide arrester, so that the operation safety index of the arrester resistive current measurement is improved.
The measurement method further comprises:
according to the formula
Figure BDA0002733396240000072
And performing reverse thrust on the current integral of the end screen 61 of the in-phase main transformer high-voltage bushing to obtain the MOA voltage to be measured. Because the high-voltage end of the main transformer bushing has large capacitance to the ground, the dielectric loss tangent value is less than 0.1 percent, the corresponding dielectric loss angle is extremely small, and is far less than the equivalent dielectric loss angle of the zinc oxide arrester. Therefore, the main transformer bushing end screen leakage current IT is considered to lead the bus voltage by 90 degrees.
The application provides an MOA resistive current measuring method for reconstructing voltage by leakage current, which comprises the following steps: obtaining a current signal I of an MOA grounding down lead to be testedXThe current signal I of the in-phase capacitive equipment grounding down lead; MOA data K obtained by linear transformation1IXAnd in-phase capacitive device data K2I; performing analog-to-digital conversion to obtain digital quantity, and performing Fourier transform; extracting fundamental wave angle phi in MOA result after Fourier transformXAnd fundamental angle Φ in-phase capacitive device results; phase comparison is carried out to obtain an equivalent dielectric loss angle theta of the lightning arrester; obtaining the resistive current I of the lightning arresterR＝IXX sin θ. The method can realize rapid and accurate acquisition of the resistive current of the zinc oxide arrester in the power grid, is simple and safe to operate, can provide reliable guarantee for performance evaluation of the zinc oxide arrester, safety of power equipment and the like, provides technical support for safe and reliable operation and modification decision of a power system, and adopts measurement without a voltage transformerThe MOA voltage to be measured is obtained in a mode, so that the action of a protection device is avoided, and the safety of a power system is improved.
The above-mentioned contents are only for explaining the technical idea of the present application, and the protection scope of the present application is not limited thereby, and any modification made on the basis of the technical idea presented in the present application falls within the protection scope of the claims of the present application.
Additionally, the order in which elements and sequences of the processes described herein are processed, the use of alphanumeric characters, or the use of other designations, is not intended to limit the order of the processes and methods described herein, unless explicitly claimed. While various presently contemplated embodiments have been discussed in the foregoing disclosure by way of example, it should be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.
Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.
The entire contents of each patent, patent application publication, and other material cited in this application, such as articles, books, specifications, publications, documents, and the like, are hereby incorporated by reference into this application. Except where the application is filed in a manner inconsistent or contrary to the present disclosure, and except where the claim is filed in its broadest scope (whether present or later appended to the application) as well. It is noted that the descriptions, definitions and/or use of terms in this application shall control if they are inconsistent or contrary to the statements and/or uses of the present application in the material attached to this application.

Claims (4)

1. An MOA resistive current measurement method for reconstructing voltage by leakage current is characterized by comprising the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXThe current signal I of the in-phase capacitive equipment grounding down lead;
the current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the in-phase capacitive equipment grounding down lead obtains MOA data K to be measured through linear transformation1IXAnd in-phase capacitive device data K2I；
The MOA data K to be tested1IXAnd said in-phase capacitive device data K2I, performing analog-to-digital conversion on the digital value, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental angle Φ in-phase capacitive device results;
the fundamental wave angle phiXComparing the phase with the fundamental wave angle phi to obtain an equivalent dielectric loss angle theta of the lightning arrester;
calculating the resistive current I of the lightning arresterR＝IX×sinθ。
2. The MOA resistive current measurement method of leakage current reconstructed voltage according to claim 1, characterized in that the in-phase capacitive device is an in-phase high voltage capacitor; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of grounding down lead of in-phase high-voltage capacitorC；
The current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the in-phase high-voltage capacitor grounding down leadCObtaining MOA data to be measured through linear transformationK1IXAnd in-phase high voltage capacitor data K2IC；
The MOA data K to be tested1IXAnd said in-phase high voltage capacitor data K2ICPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental angle phi in-phase high-voltage capacitor resultsC；
The fundamental wave angle phiXAnd the fundamental wave angle phiCPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterC；
Calculating the resistive current I of the lightning arresterRC＝IX×sinθC。
3. The MOA resistive current measurement method of leakage current reconstructed voltage according to claim 1, characterized in that the in-phase capacitive device is an in-phase current transformer; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of grounding down lead of in-phase current transformerTA；
The current signal I of the MOA to be tested grounding down leadXAnd the current signal I of the grounding down lead of the in-phase current transformerTAObtaining MOA data K to be measured through linear transformation1IXAnd in-phase current transformer data K2ITA；
The MOA data K to be tested1IXAnd said in-phase current transformer data K2ITAPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental angle phi in-phase current transformer resultTA；
The fundamental wave angle phiXAnd the fundamental wave angle phiTAPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterTA；
To obtainResistive current I of lightning arresterRTA＝IX×sinθTA。
4. The MOA resistive current measurement method of leakage current reconstructed voltage according to claim 1, characterized in that the in-phase capacitive device is an in-phase main transformer bushing; the measuring method comprises the following steps:
obtaining a current signal I of an MOA grounding down lead to be testedXCurrent signal I of end screen of high-voltage bushing of in-phase main transformerT；
The current signal I of the MOA to be tested grounding down leadXAnd a current signal I of a high-voltage bushing end screen of the in-phase main transformerTObtaining MOA data K to be measured through linear transformation1IXAnd in-phase main transformer casing data K2IT；
The MOA data K to be tested1IXAnd said in-phase main transformer casing data K2ITPerforming analog-to-digital conversion to obtain digital quantity, and performing Fourier transform;
extracting fundamental wave angle phi in MOA result to be detected after Fourier transformXAnd fundamental wave angle phi in-phase main transformer casing resultT；
The fundamental wave angle phiXAnd the fundamental wave angle phiTPhase comparison is carried out to obtain the equivalent dielectric loss angle theta of the lightning arresterT；
Calculating the resistive current I of the lightning arresterRT＝IX×sinθT。
CN202011125246.3A 2020-10-20 2020-10-20 MOA resistive current measuring method for leakage current reconstruction voltage Pending CN112305351A (en)

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