CN115902477A - Lightning arrester operation state detection method based on digital twinning - Google Patents
Lightning arrester operation state detection method based on digital twinning Download PDFInfo
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Abstract
The invention discloses a digital twin-based lightning arrester operation state detection method, which comprises the steps of obtaining equipment parameters, operation data and external information of a lightning arrester to be modeled, and obtaining installation information of the lightning arrester in a power grid topology; performing characteristic mapping on an arrester entity from an electrical perspective, and establishing an arrester digital twin model considering an arrester aging factor according to an improved resistive current algorithm; correcting a digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance; on the basis of a digital twinning model, online detection of the lightning arrester considering harmonic influence is carried out, the aging state evaluation of the lightning arrester is provided by using a harmonic analysis method, and the lightning arrester is divided into three grades of non-aging, middle aging and complete aging according to the calculation result; the technical problems that a common lightning arrester model is simple and effective in detection of leakage current, but errors can be gradually increased along with the influences of aging, wetting and the like, so that the online detection effectiveness is insufficient and the like are solved.
Description
Technical Field
The invention belongs to the technical field of lightning arrester operation state detection, and particularly relates to a digital twin-based lightning arrester operation state detection method.
Background
The lightning arrester is an important protection device for suppressing overvoltage, releasing impact heavy current and protecting power equipment from being damaged by lightning in a power system, and the stability of a power grid system is greatly influenced by the running state of the lightning arrester. However, due to the influence of factors such as external environment, power supply voltage, power grid harmonics, and damp and aging phenomena inside equipment for a long time, the insulation performance and sensitivity of the valve plate inside the lightning arrester will have different degrees of deviation, so that the traditional online detection method has a large error on the lightning arrester, and how to establish a lightning arrester model considering the influence of factors such as aging and damp becomes a difficult problem of online detection of the lightning arrester. Meanwhile, equipment in the existing power grid station is often arranged densely, interphase and space interference currents are easily generated by coupling capacitors existing between electrified conductors, large interference is brought to detection of leakage currents and the like of the lightning arrester, and an interphase and space interference-considered related model and algorithm need to be established. The most commonly used lightning arrester model at present is a small current area model only considering the resistance and capacitance characteristics in a normal state, and although the model is simple and effective for detecting leakage current, the error is gradually increased along with the influences of aging, wetting and the like, so that the on-line detection effectiveness is insufficient.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method is used for solving the technical problems that a common lightning arrester model is a small current area model only considering the resistance and capacitance characteristics in a normal state, the model is simple and effective for detecting leakage current, but errors are gradually increased along with the influences of aging, wetting and the like, so that the on-line detection effectiveness is insufficient, and the like.
The technical scheme of the invention is as follows:
a method for detecting an operational state of a lightning arrester based on digital twinning, the method comprising:
step 1: acquiring equipment parameters, operation data and external information of the lightning arrester to be modeled, and acquiring installation information of the lightning arrester in a power grid topology;
step 2: performing characteristic mapping on an arrester entity from an electrical perspective, and establishing an arrester digital twin model considering the aging factors of the arrester according to an improved resistive current algorithm;
and step 3: correcting a digital twinborn model of the lightning arrester by considering the interference of the interphase stray capacitance;
and 4, step 4: on the basis of a digital twinning model, the lightning arrester on-line detection considering the harmonic influence is carried out;
and 5: and based on the digital twin model information, utilizing a harmonic analysis method to provide lightning arrester aging state assessment, and dividing the lightning arrester into three grades of non-aging, middle aging and complete aging according to a calculation result.
Acquiring parameters of lightning arrester equipment to be modeled, wherein the parameters comprise electrical parameters and structural parameters; the electrical parameters comprise a volt-ampere characteristic curve, a rated voltage, a continuous operation voltage, a residual voltage under a nominal discharge current and a maximum discharge current, and the structural parameters comprise the model of the lightning arrester, the material of a valve plate, the quality and the specific heat capacity parameters.
The method for acquiring the installation information in the power grid topology comprises the following steps: and acquiring the voltage grade of the power grid, determining the access mode and the protection range of the lightning arrester, and acquiring a power grid topological graph and a mounting distribution diagram of the lightning arrester on the power grid.
The step 2 specifically comprises the following steps:
2.1, establishing a basic digital twin model of the arrester based on the acquired arrester equipment parameters;
the lightning arrester is equivalent to a parallel circuit of a capacitor C branch and a nonlinear resistor R branch according to a lightning arrester volt-ampere characteristic curve; leakage current i of lightning arrester X Divided into resistive currents i R And a capacitive current i C Two parts, the calculation formula is as follows:
wherein u is the voltage of applying to the arrester both ends, and k is the constant that the arrester self ageing degree decided:
step 2.2, eliminating the capacitive current based on a capacitive current compensation method, thereby obtaining a resistive current; considering the influence of the harmonic on the capacitive current, the capacitive current component is calculated according to u, as follows:
i R ＝i X -i C
wherein omega is alternating current frequency, and n is harmonic frequency;
step 2.3, correcting the nonlinear equivalent resistance according to an improved resistive current algorithm, and establishing a digital twin model of the arrester, which takes the influence of the aging of the arrester on the resistance into consideration;
the resistance of the nonlinear resistor R generating fundamental resistive current is equivalent to a linear resistor R 1 The rest part is equivalent to a nonlinear resistor R 2 So that the nonlinear resistance R is equivalent to R 1 And R 2 Are connected in parallel; for resistive current i according to a basic twin circuit model R Performing FFT decomposition as shown in the following formula:
wherein theta is x Is the phase of the x-th harmonic current;
calculating the resistive current amplitude I of the x harmonic at the fundamental wave MX1 As shown in the following formula:
calculating to obtain R 1 Linear equivalent resistance, then according to R 1 To obtain R 2 As shown in the following equation, where θ is the phase of the fundamental current:
R 2 ＝tanu/k-R 1 。
step 3, the step of correcting the digital twin model of the lightning arrester specifically comprises the following steps:
step 3.1, correcting the digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance, and setting the interphase stray capacitance as C AB 、C BA 、C BC 、C BC When the lightning arrester is connected into a three-phase circuit in a linear mode, the four stray capacitance parameters are equal, and a true value correction formula of each resistive current is obtained through a harmonic analysis method, wherein the formula is shown as the following formula
Is the included angle between the current and the voltage at the current moment>
The included angle between each phase current and voltage is as follows:
step 3.2, collecting three-phase leakage current I of the lightning arrester A 、I B 、I C And three-phase voltage signal U A 、U B 、U C And calculating corresponding amplitude and phase information;
3.3, calculating zero sequence and positive sequence current components of three-phase current, and calculating full current amplitude and included angle information after B-phase compensation;
3.4, calculating amplitude and included angle information after compensation of the phase B initial running time, calculating corresponding resistive current, and further calculating and correcting parameters of the lightning arrester capacitor and resistor according to the step 2;
and 3.5, taking the initial value calculated by the phase B as a reference for each phase, adding the variable quantity of the amplitude and the included angle of each phase as a calculation result, calculating corresponding resistive current, and further calculating and correcting parameters of the capacitor and the resistor of the lightning arrester according to the step 2.
Step 4, based on the digital twin model, the specific method for online detection of the lightning arrester considering harmonic influence comprises the following steps:
step 4.1, the leakage current comprises a resistive component and a capacitive component, as shown in the following formula,
wherein alpha is k The phase angle of each harmonic current;
step 4.2, multiplying sin (n ω t + α) on both sides simultaneously n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Rk ＝I km cos(β k -α k )
step 4.3, multiplying cos (n ω t + α) simultaneously on both sides n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Ck ＝I km sin(β k -α k )
and calculating the total current, the resistive current and the capacitive current of each phase in real time, and setting alarm thresholds of the total current, the resistive current and the capacitive current of each phase according to the calculated current values in normal operation and various fault operation, thereby realizing fault early warning of the lightning arrester body.
The step 5 specifically comprises the following steps:
and 5.1, simplifying the calculation of the resistive current component of the leakage current in the step 4, and quickly calculating by the following formula, wherein M is an intermediate constant variable and can be solved by using average power definition, u is the terminal voltage measured by the lightning arrester, and i is the measured leakage current:
i r ＝u/M
step 5.2, the fundamental wave resistive current i of the leakage current r1 Can be calculated from the following formula,
i r1 ＝u 1 /M
wherein the fundamental voltage u 1 Can be obtained by FFT calculation of voltage;
(3) According to the step 2, the fundamental wave resistive current i of k and leakage current is obtained through simulation calculation of the digital twin model r1 In relation to each other, and according to the fundamental resistive current i corresponding to k =40,25,12, respectively r1 The values are used as the judgment values of three grades of the non-aging, the middle aging and the complete aging of the lightning arrester.
When the lightning arrester is detectedi r1 Less than k =40 for i r1 When the value is positive, the state is an unaged state; when the lightning arrester i is detected r1 Greater than k =40 corresponds to i r1 Values of and less than k =25 correspond to i r1 When the value is positive, the aging medium-term state is obtained; when the lightning arrester i is detected r1 Greater than k =12 corresponds to i r1 At this value, the aging state was complete.
The invention has the beneficial effects that:
the digital twin model established by the method considers factors such as the aging of the lightning arrester, the inter-phase stray capacitance and the like, has more accurate calculation on the running state of the lightning arrester compared with the traditional simulation model, reduces the error caused by the reduction of the insulation performance due to the aging of the valve block in the lightning arrester, and is favorable for more accurately detecting the running state of the lightning arrester on line. Meanwhile, the online detection method based on the digital twin model is high in calculation speed and more suitable for practical engineering application, and the aging state evaluation method of the lightning arrester can clearly evaluate the aging state of the lightning arrester and is beneficial to arrangement of maintenance and other work.
The model solves the technical problems that a common lightning arrester model is a small current area model only considering the resistance and capacitance characteristics in a normal state, the model is simple and effective for detecting leakage current, but errors can be gradually increased along with the influences of aging, wetting and the like, so that the online detection effectiveness is insufficient, and the like.
Drawings
FIG. 1 is a flow chart of the steps of the method of the present invention;
fig. 2 is a diagram of the leakage current of the arrester measured in the example.
Detailed Description
The invention relates to a method for detecting the running state of a lightning arrester based on digital twinning, which comprises the steps of firstly, establishing a digital twinning model of the lightning arrester according to the equipment parameters, running data and external information of the lightning arrester and by considering the influence of aging factors of the lightning arrester; secondly, correcting a digital twin model of the lightning arrester based on installation information of the lightning arrester in a power grid and considering the interference of interphase stray capacitance; then, based on a digital twinning model, providing an arrester online detection method considering harmonic influence; finally, lightning arrester aging state evaluation method is provided by utilizing harmonic analysis method
The method comprises the following steps:
step 1: acquiring equipment parameters, operation data and external information of the lightning arrester to be modeled, and acquiring installation information of the lightning arrester in power grid topology;
and 2, step: performing characteristic mapping on an arrester entity from an electrical perspective, and establishing an arrester digital twin model considering the aging factors of the arrester according to an improved resistive current algorithm;
and step 3: correcting a digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance;
and 4, step 4: based on a digital twinning model, providing an arrester online detection method considering harmonic influence;
and 5: and based on the digital twin model information, a lightning arrester aging state evaluation method is provided by utilizing a harmonic analysis method, and the lightning arrester is divided into three grades of non-aging, middle-aging and complete aging according to a calculation result.
Further, the step 1 specifically comprises:
acquiring equipment parameters of the lightning arrester to be modeled, wherein the equipment parameters comprise electrical parameters and structural parameters, the electrical parameters comprise a volt-ampere characteristic curve, a rated voltage, a continuous operation voltage, residual voltage under a nominal discharge current and a maximum discharge current, and the structural parameters comprise the model of the lightning arrester, the material and the mass of a valve plate and specific heat capacity parameters;
the method comprises the steps of obtaining the power grid structure information of the regional lightning arrester, obtaining the power grid voltage grade, determining the access mode and the protection range of the lightning arrester, and obtaining a power grid topological graph and a power grid installation distribution diagram of the lightning arrester.
Further, the step 2 specifically includes:
(1) And establishing a basic digital twin model of the lightning arrester based on the acquired lightning arrester equipment parameters.
And the lightning arrester is equivalent to a parallel circuit of a capacitor C branch and a nonlinear resistor R branch according to the voltage-current characteristic curve of the lightning arrester. Under this model, the leakage current i of the arrester X Dividable into resistive currents i R And a capacitive current i C Two parts, the calculation formula is as follows, wherein u isExerting in the arrester both ends voltage, k is the constant that the arrester self ageing degree decided:
(2) And eliminating the capacitive current based on a capacitive current compensation method, thereby obtaining the resistive current. Considering the influence of the harmonic on the capacitive current, the capacitive current component is calculated according to u, as shown in the following formula, where ω is the alternating current frequency, and n is the harmonic number:
i R ＝i X -i C
(3) And correcting the nonlinear equivalent resistance according to an improved resistive current algorithm, and establishing a digital twin model of the lightning arrester, which takes the influence of the aging of the lightning arrester on the resistance into consideration.
The resistance of the nonlinear resistor R generating fundamental resistive current is equivalent to a linear resistor R 1 The rest part is equivalent to a nonlinear resistor R 2 So that the nonlinear resistance R is equivalent to R 1 And R 2 Are connected in parallel. For resistive current i according to a basic twin circuit model R FFT decomposition is performed as shown in the following formula, wherein theta x Phase for x harmonic current:
calculating the resistive current amplitude of the x harmonic at the fundamental waveI MX1 As shown in the following formula:
calculating to obtain R 1 Linear equivalent resistance, then according to R 1 To obtain R 2 As shown in the following equation, where θ is the phase of the fundamental current:
R 2 ＝tanu/k-R 1
further, the step 3 specifically includes:
and correcting the digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance. Set the stray capacitance between phases as C AB 、C BA 、C BC 、C BC When the lightning arrester is connected into a three-phase circuit in a linear mode, the four stray capacitance parameters are equal, and a true value correction formula of each resistive current is obtained through a harmonic analysis method, wherein the formula is shown as the following formula
Is the included angle between the current and the voltage at the current moment>
The included angle between each phase current and voltage is as follows:
(1) Three-phase leakage current I of collecting lightning arrester A 、I B 、I C And three-phase voltage signal U A 、U B 、U C And corresponding amplitude and phase information is calculated.
(2) And calculating zero sequence and positive sequence current components of the three-phase current, and calculating full current amplitude and included angle information after B-phase compensation.
(3) And (3) calculating the amplitude and included angle information after the compensation of the initial running time of the phase B, calculating the corresponding resistive current, and further calculating and correcting the parameters of the capacitor and the resistor of the lightning arrester according to the step 2.
(4) And (3) taking the initial value calculated by the phase B as a reference, adding the variable quantity of the amplitude and the included angle of each phase as a calculation result, calculating corresponding resistive current, and further calculating and correcting parameters of the capacitor and the resistor of the lightning arrester according to the step 2.
Further, the step 4 specifically includes:
and providing an arrester on-line detection method considering harmonic influence based on the corrected arrester digital twin model.
(1) From the digital twinning model of the arrester, the leakage current includes a resistive component and a capacitive component, as shown in the following formula, where α k Phase angle for each harmonic current:
(2) For both sides of the 4.1 formula, sin (n ω t + α) is multiplied simultaneously n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Rk ＝I km cos(β k -α k )
(3) Multiplying cos (n ω t + α) simultaneously on both sides of 4.1 n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Ck ＝I km sin(β k -α k )
(4) And calculating the total current, the resistive current and the capacitive current of each phase in real time according to the formula, and setting alarm thresholds of the total current, the resistive current and the capacitive current of each phase according to the magnitude of each current calculated in normal operation and various fault operation, thereby realizing fault early warning of the lightning arrester body.
Further, the step 5 specifically includes:
and based on the digital twin model information, utilizing a harmonic analysis method to provide lightning arrester aging state assessment, and dividing the lightning arrester into three grades of non-aging, middle aging and complete aging according to a calculation result.
The constant k reflecting the degree of aging of the arrester itself in step 2 decreases as the degree of aging increases. Therefore, the aging degree of the lightning arrester can be judged according to the resistive component of the fundamental wave of the leakage current, so that the scientificity of judging the aging degree of the lightning arrester in the online running state is improved.
(1) Because the current and voltage phases of the resistive component of the leakage current are the same and the requirement on the accuracy of the aging degree judgment is not high, the calculation of the resistive current component of the leakage current in the step 4 can be simplified and can be quickly calculated according to the following formula, wherein M is an intermediate constant variable and can be used for defining and solving by using average power, u is the terminal voltage measured by the lightning arrester, and i is the measured leakage current:
i r ＝u/M
(2) Fundamental resistive current i of leakage current r1 Can be calculated by the following formula, wherein the fundamental voltage u 1 It can be calculated by FFT on the voltage:
i r1 ＝u 1 /M
(3) Obtaining k and fundamental resistive current i of leakage current through simulation calculation according to the digital twin model in the step 2 r1 In relation to each other, and according to the fundamental resistive current i corresponding to k =40,25,12, respectively r1 The values are used as the judgment values of three grades of the non-aging, the middle aging and the complete aging of the lightning arrester. When the lightning arrester i is detected r1 Less than k =40 corresponds to i r1 At the value of, is not agedA state; when the lightning arrester i is detected r1 Greater than k =40 corresponds to i r1 Values of and less than k =25 correspond to i r1 When the value is positive, the state is an aging middle stage state; when the lightning arrester i is detected r1 Greater than k =12 corresponds to i r1 At this value, the aging state was complete.
Examples
In the embodiment, a lightning arrester of a power grid in a certain area is adopted to carry out digital twin modeling and lightning arrester aging assessment, the lightning arrester is a zinc oxide lightning arrester, the lightning arrester is connected to a certain node of a 1kV three-phase alternating-current power grid in a straight line arrangement mode, the lightning arrester is not aged, k =49 is obtained through equipment tests, the capacitance C =246.3pF is obtained, and the leakage current i of the lightning arrester X The measurements are shown in FIG. 2.
The lightning arrester is equivalent to a parallel circuit of a capacitor C branch and a nonlinear resistor R branch. Under this model. The capacitive current component is calculated as shown in the following equation:
i R ＝i X -i C
for resistive current i according to a basic twin circuit model R Performing FFT decomposition, as shown in the following formula:
calculating the resistive current amplitude I of the x harmonic at the fundamental wave MX1 As shown in the following formula:
calculating to obtain R 1 Linear equivalent resistance, as shown in the following equation:
and (3) performing calculation and evaluation on the aging state of the lightning arrester as follows:
the measuring device measures the terminal voltage and the leakage total current of the B-phase lightning arrester, and an intermediate parameter M is calculated according to the following formula:
fundamental resistive current i of leakage current r1 Calculated from the following formula:
i r1 ＝u 1 /M＝30.7uA
fundamental resistive current i according to k and leakage current r1 The relation yields that the arrester k =49.6, the arrester being in an unaged state.
Claims (8)
1. A lightning arrester operation state detection method based on digital twinning is characterized in that: the method comprises the following steps:
step 1: acquiring equipment parameters, operation data and external information of the lightning arrester to be modeled, and acquiring installation information of the lightning arrester in a power grid topology;
step 2: performing characteristic mapping on an arrester entity from an electrical perspective, and establishing an arrester digital twin model considering the aging factors of the arrester according to an improved resistive current algorithm;
and step 3: correcting a digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance;
and 4, step 4: on the basis of a digital twinning model, the lightning arrester on-line detection considering the harmonic influence is carried out;
and 5: and based on the digital twin model information, utilizing a harmonic analysis method to provide lightning arrester aging state assessment, and dividing the lightning arrester into three grades of non-aging, middle aging and complete aging according to a calculation result.
2. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: acquiring parameters of lightning arrester equipment to be modeled, wherein the parameters comprise electrical parameters and structural parameters; the electrical parameters comprise a volt-ampere characteristic curve, a rated voltage, a continuous operation voltage, a residual voltage under a nominal discharge current and a maximum discharge current, and the structural parameters comprise the model of the lightning arrester, the material of a valve plate, the quality and the specific heat capacity parameters.
3. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: the method for acquiring the installation information in the power grid topology comprises the following steps: and acquiring the voltage grade of the power grid, determining the access mode and the protection range of the lightning arrester, and acquiring a power grid topological graph and a mounting distribution diagram of the lightning arrester on the power grid.
4. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: the step 2 specifically comprises the following steps:
2.1, establishing a basic digital twin model of the lightning arrester based on the acquired parameters of the lightning arrester equipment;
the lightning arrester is equivalent to a parallel circuit of a capacitor C branch and a nonlinear resistor R branch according to a lightning arrester volt-ampere characteristic curve; leakage current i of lightning arrester X Divided into resistive currents i R And a capacitive current i C Two parts, the calculation formula is as follows:
wherein u is applying in arrester both ends voltage, and k is the constant that the arrester self ageing degree decided:
step 2.2, eliminating the capacitive current based on a capacitive current compensation method, so as to obtain a resistive current; considering the influence of the harmonic on the capacitive current, the capacitive current component is calculated according to u, as follows:
i R ＝i X -i C
wherein omega is alternating current frequency, and n is harmonic frequency;
step 2.3, correcting the nonlinear equivalent resistance according to an improved resistive current algorithm, and establishing a digital twin model of the arrester, which takes the influence of the aging of the arrester on the resistance into consideration;
the resistance of the nonlinear resistor R generating fundamental resistive current is equivalent to a linear resistor R 1 The rest part is equivalent to a nonlinear resistor R 2 So that the nonlinear resistance R is equivalent to R 1 And R 2 Are connected in parallel; for resistive current i according to a basic twin circuit model R Performing FFT decomposition as shown in the following formula:
wherein theta is x Is the phase of the x harmonic current;
calculating the resistive current amplitude I of the x harmonic at the fundamental wave MX1 As shown in the following formula:
calculating to obtain R 1 Linear equivalent resistance, then according to R 1 To obtain R 2 As shown in the following equation, where θ is the phase of the fundamental current:
R 2 ＝tanu/k-R 1 。
5. the method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: step 3, the step of correcting the digital twin model of the lightning arrester specifically comprises the following steps:
step 3.1, correcting the digital twin model of the lightning arrester by considering the interference of the interphase stray capacitance, and setting the interphase stray capacitance as C AB 、C BA 、C BC 、C BC When the lightning arrester is connected into a three-phase circuit in a linear mode, the four stray capacitance parameters are equal, and a true value correction formula of each resistive current is obtained through a harmonic analysis method, wherein the formula is shown as the following formula
For the included angle between the current and the voltage at the current moment>
The included angle between each phase current and voltage is as follows:
step 3.2, collecting three-phase leakage current I of the lightning arrester A 、I B 、I C And three-phase voltage signal U A 、U B 、U C And calculating corresponding amplitude and phase information;
3.3, calculating zero sequence and positive sequence current components of three-phase current, and calculating full current amplitude and included angle information after B-phase compensation;
step 3.4, calculating amplitude and included angle information after compensation of the phase B initial running time, calculating corresponding resistive current, and further calculating and correcting parameters of the lightning arrester capacitor and resistor according to the step 2;
and 3.5, taking the initial value calculated by the phase B as a reference for each phase, adding the variation of the amplitude and the included angle of each phase as a calculation result, calculating corresponding resistive current, and further calculating and correcting the parameters of the capacitor and the resistor of the lightning arrester according to the step 2.
6. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: step 4, based on the digital twin model, the specific method for online detection of the lightning arrester considering the harmonic influence comprises the following steps:
step 4.1, the leakage current comprises a resistive component and a capacitive component, as shown in the following formula,
wherein alpha is k The phase angle of each harmonic current;
step 4.2, multiplying sin (n ω t + α) on both sides simultaneously n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Rk ＝I km cos(β k -α k )
step 4.3, multiplying cos (n ω t + α) simultaneously on both sides n ) And making constant integral calculation for two sides of the equation in a period, and simplifying to obtain the following formula:
I Ck ＝I km sin(β k -α k )
and calculating the total current, the resistive current and the capacitive current of each phase in real time, and setting alarm thresholds of the total current, the resistive current and the capacitive current of each phase according to the calculated current values in normal operation and various fault operation, thereby realizing fault early warning of the lightning arrester body.
7. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 1, characterized in that: the step 5 specifically comprises the following steps:
and 5.1, simplifying the calculation of the resistive current component of the leakage current in the step 4, and quickly calculating by using the following formula, wherein M is an intermediate constant variable and can be solved by using average power definition, u is the end voltage measured by the lightning arrester, and i is the measured leakage current:
i r ＝u/M
step 5.2, the fundamental wave resistive current i of the leakage current r1 Can be calculated from the following formula,
i r1 ＝u 1 /M
wherein the fundamental voltage u 1 Can be obtained by FFT calculation of voltage;
(3) According to the step 2, the fundamental wave resistive current i of k and leakage current is obtained through simulation calculation of the digital twin model r1 In relation to each other, and according to the fundamental resistive current i corresponding to k =40,25,12, respectively r1 The values are used as the judgment values of three grades of the non-aging, the middle aging and the complete aging of the lightning arrester.
8. The method for detecting the running state of the lightning arrester based on the digital twin as claimed in claim 7, characterized in that: when the lightning arrester i is detected r1 Less than k =40 for i r1 When the value is positive, the state is an unaged state; when the lightning arrester i is detected r1 Greater than k =40 corresponds toi r1 Values of and less than k =25 correspond to i r1 When the value is positive, the aging medium-term state is obtained; when the lightning arrester i is detected r1 Greater than k =12 corresponds to i r1 At this value, the aging state was complete.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211506181.6A CN115902477A (en) | 2022-11-28 | 2022-11-28 | Lightning arrester operation state detection method based on digital twinning |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117741356A (en) * | 2023-12-04 | 2024-03-22 | 国网宁夏电力有限公司电力科学研究院 | Lightning arrester valve plate aging evaluation method, medium and system under complex working conditions |
| CN118131117A (en) * | 2024-05-07 | 2024-06-04 | 南京电力自动化设备三厂有限公司 | Automatic aging method and system for electric energy meter assembly line |
| CN118376865A (en) * | 2024-06-21 | 2024-07-23 | 苏州华电电气股份有限公司 | Rapid detection method and system for direct current characteristics of lightning arrester |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117741356A (en) * | 2023-12-04 | 2024-03-22 | 国网宁夏电力有限公司电力科学研究院 | Lightning arrester valve plate aging evaluation method, medium and system under complex working conditions |
| CN117741356B (en) * | 2023-12-04 | 2024-06-11 | 国网宁夏电力有限公司电力科学研究院 | Lightning arrester valve plate aging evaluation method, medium and system under complex working conditions |
| CN118131117A (en) * | 2024-05-07 | 2024-06-04 | 南京电力自动化设备三厂有限公司 | Automatic aging method and system for electric energy meter assembly line |
| CN118376865A (en) * | 2024-06-21 | 2024-07-23 | 苏州华电电气股份有限公司 | Rapid detection method and system for direct current characteristics of lightning arrester |
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