CN107091966A - A kind of method for determining the maximum allowable resistive leakage current of Zinc-Oxide Arrester - Google Patents
A kind of method for determining the maximum allowable resistive leakage current of Zinc-Oxide Arrester Download PDFInfo
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- CN107091966A CN107091966A CN201710438892.7A CN201710438892A CN107091966A CN 107091966 A CN107091966 A CN 107091966A CN 201710438892 A CN201710438892 A CN 201710438892A CN 107091966 A CN107091966 A CN 107091966A
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- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 title claims abstract description 384
- 239000011787 zinc oxide Substances 0.000 title claims abstract description 192
- 238000000034 method Methods 0.000 title claims abstract description 20
- 229960001296 zinc oxide Drugs 0.000 title abstract 13
- 230000008859 change Effects 0.000 claims abstract description 15
- 239000007787 solid Substances 0.000 claims description 11
- 229910052755 nonmetal Inorganic materials 0.000 claims description 6
- DLINORNFHVEIFE-UHFFFAOYSA-N hydrogen peroxide;zinc Chemical compound [Zn].OO DLINORNFHVEIFE-UHFFFAOYSA-N 0.000 abstract 1
- 229940105296 zinc peroxide Drugs 0.000 abstract 1
- 238000004364 calculation method Methods 0.000 description 14
- 230000005684 electric field Effects 0.000 description 14
- 238000010586 diagram Methods 0.000 description 9
- 238000006073 displacement reaction Methods 0.000 description 6
- 239000004020 conductor Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229910052573 porcelain Inorganic materials 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 230000005686 electrostatic field Effects 0.000 description 4
- 239000013598 vector Substances 0.000 description 4
- 230000033228 biological regulation Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 230000005672 electromagnetic field Effects 0.000 description 2
- 230000008571 general function Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- 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
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Abstract
The present invention provides a kind of method for determining the maximum allowable resistive leakage current of Zinc-Oxide Arrester, including：Set up the three-dimensional entity model of Zinc-Oxide Arrester；Grid division；Set the boundary condition of grid property and Zinc-Oxide Arrester three-dimensional entity model, the actual operating voltage of loading Zinc-Oxide Arrester；To Zinc-Oxide Arrester, the current potential of practical operation situation is calculated under actual operating voltage, is obtained the potential value of each zinc oxide resistance sheet of Zinc-Oxide Arrester, is obtained the capacitive leakage current values of zinc oxide resistance sheet；Calculate the resistive leakage current of the dirty zinc peroxide resistor disc of different resistivity；Obtain the relation of resistive leakage current situation of change and ZnO resistors sheet resistivity；Calculate maximum allowable resistive leakage current.Damp degree of the invention by judging the calculating of the zinc oxide lightning arrester block property leakage current rate of change Zinc-Oxide Arrester, can be estimated to the failure situation of Zinc-Oxide Arrester, so as to carry out effective early warning to Zinc-Oxide Arrester.
Description
Technical Field
The invention belongs to the technical field of high-voltage electric appliances, and particularly relates to a method for determining the maximum allowable resistive leakage current of a zinc oxide arrester.
Background
The lightning arrester is mainly used for limiting lightning overvoltage transmitted by a line or internal overvoltage caused by operation in a power system and ensuring the normal operation of the system. The zinc oxide arrester has excellent nonlinear characteristics, good protection characteristics, large through-current capacity and simple structure, provides better protection level and larger protection margin, and is widely applied. Although the production level of zinc oxide lightning arrester materials is continuously improved, the valve plate can be gradually aged due to the long-term bearing of factors such as power frequency voltage, overvoltage and dampness, the valve plate is increased in leakage current and temperature is increased, and finally power grid accidents are caused.
Factors causing the zinc oxide arrester to break down mainly include moisture, short circuit and the like, and moisture accidents account for more than 60% of the total accident rate of the zinc oxide arrester. The change of the operating state of the zinc oxide arrester is directly reflected on the change of the resistive leakage current of the zinc oxide arrester, and the increase and the sudden change of the resistive leakage current are main reasons for the fault of the zinc oxide arrester, so the monitoring of the resistive leakage current is an effective means for detecting the fault of the zinc oxide arrester.
And according to relevant regulations of a Liaoning lightning protection technology service center, judging the piezoresistor with the numerical value variation of the leakage current exceeding 10 percent as the failed piezoresistor. The damp degree of the zinc oxide arrester is reflected by the variation rate of the resistive leakage current of the zinc oxide arrester, the stable operation of the zinc oxide arrester and the safety allowance of a power system are considered, the relation between the variation condition of the resistive leakage current and the damp state of the zinc oxide arrester is obtained, and the maximum allowable resistive current of the zinc oxide arrester is obtained.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for determining the maximum allowable resistive leakage current of a zinc oxide arrester so as to achieve the purposes of conveniently and visually obtaining the moisture degree of each zinc oxide resistance card in the zinc oxide arrester and better early warning the faults of the zinc oxide arrester.
The technical scheme of the invention is as follows:
a method of determining the maximum allowable resistive leakage current of a zinc oxide arrester, comprising the steps of:
step 1, establishing a three-dimensional entity model of a zinc oxide arrester;
step 2, dividing the non-metal components of the established three-dimensional entity model of the zinc oxide arrester into grids;
step 3, setting grid attributes and boundary conditions of a three-dimensional entity model of the zinc oxide arrester, and loading the actual working voltage of the zinc oxide arrester;
step 4, calculating the potential of the actual operation condition of the zinc oxide arrester under the actual working voltage to obtain the potential value of each zinc oxide resistance card of the zinc oxide arrester, and obtaining the capacitive leakage current value of the zinc oxide resistance card according to the potential difference at the two ends of the zinc oxide resistance card and the capacitance value of the zinc oxide resistance card;
step 5, calculating the resistive leakage current of the zinc oxide resistance card under different resistivities according to the structure and the size of the zinc oxide resistance card and the potential drop of the upper surface and the lower surface of the zinc oxide resistance card;
step 6, calculating the change rate of the resistive leakage current of the zinc oxide arrester according to the capacitive leakage current value and the resistive leakage current value of the zinc oxide resistance chip to obtain the relation between the change condition of the resistive leakage current and the resistivity of the zinc oxide resistance chip;
step 7, judging the piezoresistor to be a failed piezoresistor when the variation rate of the resistive leakage current of the zinc oxide resistor sheet exceeds a threshold value, and calculating the resistive leakage current when the variation rate of the resistive leakage current of the zinc oxide arrester reaches the threshold value, namely the maximum allowable resistive leakage current;
and 8, judging the moisture degree of the zinc oxide arrester according to the real-time monitored resistive leakage current value of the zinc oxide arrester, wherein the larger the resistive leakage current value is, the more serious the zinc oxide arrester is wetted.
The step 3 comprises the following steps:
step 3-1, setting grid attributes as relative dielectric constants of all elements of the zinc oxide arrester;
3-2, calculating the potential of the zinc oxide arrester through a potential control equation;
3-3, setting boundary conditions of a three-dimensional entity model of the zinc oxide arrester;
and 3-4, loading the actual working voltage of the zinc oxide arrester.
The non-metal parts of the established three-dimensional solid model of the zinc oxide arrester are divided into grids by adopting a free grid dividing method, all elements of the three-dimensional solid model of the zinc oxide arrester are sequentially subjected to grid division from inside to outside, and the elements of the same type are divided together.
In the step 4, a calculation formula of the capacitive leakage current value of the zinc oxide resistance chip is as follows:
Ii＝Ui×Ci×2πf (1)
wherein, IiIndicates the value of capacitive leakage current, U, flowing through the ith zinc oxide resistor disciThe potential difference between two ends of the ith zinc oxide resistance card is shown; ciThe capacitance value of the ith zinc oxide resistance card is shown; and f represents the power frequency.
In the step 6, the calculation formula of the change rate of the resistive leakage current of the zinc oxide resistance card is as follows:
has the advantages that:
the invention provides a method for determining the maximum allowable resistive leakage current of a zinc oxide arrester, which enables people to intuitively and conveniently obtain the moisture condition of each zinc oxide resistor disc in the zinc oxide arrester, judges the moisture degree of the zinc oxide arrester by calculating the change rate of the resistive leakage current of the zinc oxide arrester, can better evaluate the fault condition of the zinc oxide arrester, and further effectively pre-warns the zinc oxide arrester; the method has the obvious characteristics of simplicity, intuition, high calculation accuracy, clear data analysis and the like.
Drawings
Fig. 1 is a flowchart of a method for determining a maximum allowable resistive leakage current of a zinc oxide arrester according to an embodiment of the present invention;
fig. 2 is an assembly view and component assembly view of a zinc oxide arrester for a 1000kV power system according to an embodiment of the present invention, in which (a) is the assembly view; (b) is an assembly drawing of the component;
fig. 3 is an overall modeling and internal modeling diagram of a zinc oxide arrester for a 1000kV power system according to an embodiment of the present invention, in which (a) is the overall modeling diagram; (b) is an internal modeling diagram;
fig. 4 is a grid division diagram of the components of the zinc oxide arrester according to an embodiment of the invention, wherein (a) is a schematic diagram of a zinc oxide resistor disc, and (b) is a schematic diagram of a capacitor; (c) is a porcelain jacket;
fig. 5 is a graph of variation rate of resistive leakage current of a zinc oxide arrester under different moisture levels according to an embodiment of the present invention.
Detailed Description
An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.
The method for determining the maximum allowable resistive leakage current of the zinc oxide arrester in the embodiment of the invention has the flow shown in fig. 1, and comprises the following steps:
step 1, establishing a three-dimensional solid model of the zinc oxide arrester by adopting Ansys finite element software according to the sizes and the actual structures of all elements of the zinc oxide arrester;
in the embodiment of the invention, as shown in fig. 2(a) to (b), the assembly drawing and the component assembly drawing of the zinc oxide arrester for a 1000kV power system are shown; the zinc oxide resistance card is annular, the outer diameter is 136mm, the inner diameter is 54mm, and the thickness is 20 mm; the thickness of the porcelain bushing shell is 14 mm; the flange is annular, the outer diameter is 1010mm, the inner diameter is 960mm, and the thickness is 110 mm; the grading ring is of a double-layer structure, the diameter of the upper grading ring is 200mm and is arranged at a position 1180mm away from the top end of the zinc oxide arrester, and the diameter of the lower grading ring is 200mm and is arranged at a position 2300mm away from the top end of the zinc oxide arrester; in the embodiment of the invention, the material object of the zinc oxide arrester is reasonably selected, the metal nut, the connecting branch pipe of the equalizing ring and the porcelain jacket umbrella group are omitted, and the three-dimensional solid model is established strictly according to the material object size of the zinc oxide arrester, as shown in fig. 3(a) to (b), the three-dimensional solid model is the overall modeling and internal modeling diagram of the zinc oxide arrester for the 1000kV power system.
Step 2, dividing the non-metal components of the established three-dimensional entity model of the zinc oxide arrester into grids;
in the embodiment of the invention, a method for freely dividing grids is adopted to divide the non-metal parts of the established three-dimensional Solid model of the zinc oxide arrester into grids, tetrahedral grids with the type of Solid123 are selected, each element of the three-dimensional Solid model of the zinc oxide arrester is sequentially divided into grids from inside to outside, the elements of the same type are divided together, and the specific dividing sequence and the grid size are as follows:
the side length of a tetrahedral grid of the zinc oxide resistor sheet is 20 mm; the side length of a tetrahedral grid is 18 mm; the side length of the tetrahedral mesh is 15 mm; the side length of a tetrahedral grid is 45mm in an air space in the shell; the side length of a tetrahedral mesh in an air area outside the shell is 800 mm; as shown in fig. 4(a) to (c), the grid division diagram of each element of the zinc oxide arrester is shown, and the node attribute of the grid in the diagram is a potential value;
step 3, setting grid attributes and boundary conditions of a three-dimensional entity model of the zinc oxide arrester in Ansys finite element software, and loading the actual working voltage of the zinc oxide arrester;
step 3-1, setting grid attributes as relative dielectric constants of all elements of the zinc oxide arrester;
in the embodiment of the invention, the potential distribution numerical value calculation under the normal working state of the zinc oxide arrester is solved according to the electrostatic field, and the specific description is as follows:
the zinc oxide arrester normally works under the continuous operation voltage of power frequency, and the electric field of the zinc oxide arrester is the electric quasi-static field of a power frequency system; in an electric power system, the frequency of a power frequency electric field around a power transmission line is generally 50Hz, the wavelength is about 6000km, and the length of the power transmission line between transformer substations is only about 200km generally; according to the definition of quasi-static field: when the time for an electromagnetic wave to propagate through the maximum linear dimension L of the electromagnetic system under study at a velocity V is much shorter than the period T of the electromagnetic wave, the coupling effect between the electric field and the magnetic field is extremely weak, and the electromagnetic field can be considered as a quasi-static electromagnetic field. In the calculation of the potential distribution of the lightning arrester, the maximum size of the object is not more than 100m, and the definition is satisfied, therefore, the power frequency electric field generated by the transmission line can be approximately regarded as a quasi-static field, namelyWherein B represents magnetic induction and t represents time.
Thus, the maxwell system of equations is expressed as:
wherein,is a vector differential operator, and H is the magnetic field intensity; b is magnetic induction intensity; d is a potential shift; e is electric field intensityDegree; j is the current density; ρ is the charge density;
to pairThe divergence is calculated as follows:
according toThe electric field is non-rotating and the electric field strength E can still be described by a scalar potential phi:
the electric and magnetic fields are now uncoupled; the governing equation for an electric quasi-static field, which considers both the conductance σ and the dielectric constant of a material, for an electric field, can be expressed as:
for the time-harmonic field, the scalar potential φ is represented as a vector, and equation (4) becomes:
for conductors in the field, such as transmission lines, towers, flanges, earth, etc., the conductance a is generally of the order of 106The relative dielectric constant generally does not exceed 10, and the ratio of the conduction current to the displacement current is:
wherein, JcDenotes the conduction current, JdRepresenting displacement current and omega frequency.
It can be seen that the conduction current is much larger than the displacement current in the power frequency system, so, ignoring the second term in (5), the control equation can be expressed as:
it can be seen that the potentials in the conductors are not equal, but the difference is very small under the power frequency, generally, the potentials in the conductors are considered to be the same, and the suspended conductors can be processed according to a processing method in an electrostatic field in the calculation; therefore, equation (7) need not be solved.
For a medium in the field, such as air, the conductivity is approximately 0, while the conductance of a porcelain bushing, a resistor disc, an insulating rod, etc., is of the order of magnitude of less than 1012The relative dielectric constant generally does not exceed 1000, and the ratio of the conduction current to the displacement current is:
at this time, the displacement current is much larger than the conduction current, and there are:
in the electro-static field, ω and can be regarded as constant process, then equation (9) can be simplified as:
therefore, the calculation of the quasi-static electric field follows a completely similar rule with the static electric field; therefore, the numerical calculation of the potential distribution under the normal operation condition of the zinc oxide arrester can be completely solved according to the electrostatic field; considering the displacement current, setting the relative dielectric constant as the attribute of the grid of the calculation model, and looking up the data, the relative dielectric constant of each element is specifically as follows:
the relative permittivity of the zinc oxide resistor sheet was set to 650, the relative permittivity of the capacitor was set to 5, the relative permittivity of the metal material was extremely large, here 3000, the relative permittivity of the porcelain jacket was set to 7.6, and the relative permittivity of air was set to 1.
Step 3-2, calculating the potential of the zinc oxide arrester in Ansys finite element software through a potential control equation;
the formula is as follows:
3-3, setting boundary conditions of a three-dimensional entity model of the zinc oxide arrester in Ansys finite element software;
in the embodiment of the invention, the research on the electric field distribution of the zinc oxide arrester is a problem of a limited area, and a first type boundary condition and a second type boundary condition are considered;
the first type of boundary condition is also called an imposed boundary condition, and is specifically as follows:
φ|1＝g(p) (12)
where g (p) is a general function of position, and in particular may be zero or constant, indicating that the potential at a given point is given, in embodiments of the present invention, the first type of boundary condition is used for the outer boundary of the air domain, the outer surface of the tip flange, and the outer surface of the grading ring.
The second class of boundary conditions is also called natural boundary conditions, and is specifically as follows:
wherein h (p) is a general function, n is an outward normal vector of a boundary, and may be zero or constant under special conditions.
In the embodiment of the invention, each potential suspension conductor of the zinc oxide arrester is processed by adopting a coupling potential freedom degree method, namely the potential of each node on the surface of the zinc oxide arrester is considered to be equal and equal to the same value to be evaluated;
in the embodiment of the invention, the zinc oxide arrester works outdoors, the boundary of the surrounding air domain is infinite, and the problem of no domain is cut off into the problem of bounded domain when the electric field distribution is calculated, namely, the calculation boundary is set to be 5 times of the actual size of the three-dimensional solid model of the zinc oxide arrester, so that the requirement of calculation precision can be met.
In an embodiment of the invention, the permittivity of the dielectric is provided at the interface of the two dielectrics.
In the embodiment of the invention, based on the set boundary conditions, for the solving problem of the three-dimensional electric field of the zinc oxide arrester, the field distribution is described by phi (x, y, z), and then the problem becomes an equivalent variation functional function problem which meets the boundary conditions in the whole solving domain:
wherein x, y and z are three-dimensional coordinate vectors,the sum of the energy functional of each subdivision unit is obtained;
step 3-4, loading the actual working voltage of the zinc oxide arrester;
in the embodiment of the invention, 638kV continuous operation voltage is applied to the topmost flange of the zinc oxide arrester and the grading ring, and zero potential is applied to the base of the zinc oxide arrester and the boundary of an air domain, namely the grounding and the grounding are regarded as infinite;
step 4, calculating the potential of the actual operation condition of the zinc oxide arrester to obtain the potential value of each zinc oxide resistance card of the zinc oxide arrester, and obtaining the capacitive leakage current value of the zinc oxide resistance card according to the potential difference at the two ends of the zinc oxide resistance card and the capacitance value of the zinc oxide resistance card;
in the embodiment of the invention, Ansys finite element software is used for calculating an electric field model of a zinc oxide arrester for a 1000kV power system to obtain potential values of zinc oxide resistance sheets at each position on the zinc oxide arrester, and capacitive leakage current values flowing through each zinc oxide resistance sheet are calculated according to a capacitive leakage current theoretical calculation formula of the zinc oxide arrester;
the formula is as follows:
Ii＝Ui×Ci×2πf (1)
wherein, IiIndicates the value of capacitive leakage current, U, flowing through the ith zinc oxide resistor disciThe potential difference between two ends of the ith zinc oxide resistance card is shown; ciThe capacitance value of the ith zinc oxide resistance card is shown; f represents the power frequency of 50 Hz;
step 5, calculating the resistive leakage current of the downward flow zinc oxide resistance card under different moisture degrees (namely different resistivities) according to the structure and the size of the zinc oxide resistance card and the calculated potential drop of the upper surface and the lower surface of the zinc oxide resistance card;
the resistivity of the zinc oxide resistance card can reflect the degree of the zinc oxide resistance card subjected to moisture, the larger the resistivity is, the more serious the moisture is, and different resistivities are given to the zinc oxide resistance card in the three-dimensional solid model of the zinc oxide arrester; according to the structure, size and resistivity of the zinc oxide resistor discBy calculation of formula of resistanceWherein R, rho, l and s are respectively the resistance value, the resistivity, the thickness and the cross section area of the zinc oxide resistance card, the resistance value of the zinc oxide resistance card is calculated, and the resistive leakage current of the zinc oxide resistance card under different moisture degrees is calculated according to the potential values of the zinc oxide resistance cards at each position on the zinc oxide lightning arrester.
Step 6, calculating the change rate of the resistive leakage current of the zinc oxide arrester according to the capacitive leakage current value and the resistive leakage current value of the zinc oxide resistor disc to obtain the relation between the change condition of the resistive leakage current and the moisture state (the resistivity of the zinc oxide resistor disc) of the zinc oxide arrester;
the calculation formula of the resistive leakage current variation rate of the zinc oxide arrester is as follows:
in the embodiment of the invention, the change rate of the resistive leakage current of the zinc oxide resistor disc under different moisture degrees (the resistivity of the zinc oxide resistor disc is respectively 80M omega. M, 50M omega. M, 30M omega. M and 20M omega. M) of the zinc oxide arrester for the 1000kV power system is respectively calculated, as shown in fig. 5.
Step 7, judging the piezoresistor to be a failed piezoresistor when the variation rate of the resistive leakage current of the zinc oxide resistor sheet exceeds a threshold value, and calculating the resistive leakage current when the variation rate of the resistive leakage current of the zinc oxide arrester reaches 10%, namely the maximum allowable resistive leakage current;
according to the relevant regulations of the Liaoning lightning protection technical service center, the piezoresistor with the numerical value variation of the leakage current exceeding 10 percent is judged as the failed piezoresistor, and the zinc oxide resistor disc is an excellent piezoresistor material.
In the embodiment of the invention, the maximum allowable resistive leakage current of the zinc oxide arrester for the 1000kV power system is calculated to be 0.31 mA.
And 8, judging the moisture degree of the zinc oxide arrester according to the real-time monitored resistive leakage current value of the zinc oxide arrester by utilizing the relation between the change condition of the resistive leakage current and the moisture state of the zinc oxide arrester, wherein the larger the resistive leakage current value is, the more serious the zinc oxide arrester is wetted, and the fault caused by the moisture of the zinc oxide arrester can be pre-warned by comparing the calculated resistive leakage current mobility with the failure critical value of the zinc oxide resistance chip (namely the maximum allowable resistive leakage current of the zinc oxide resistance chip).
Claims (5)
1. A method for determining the maximum allowable resistive leakage current of a zinc oxide arrester, comprising the steps of:
step 1, establishing a three-dimensional entity model of a zinc oxide arrester;
step 2, dividing the non-metal components of the established three-dimensional entity model of the zinc oxide arrester into grids;
step 3, setting grid attributes and boundary conditions of a three-dimensional entity model of the zinc oxide arrester, and loading the actual working voltage of the zinc oxide arrester;
step 4, calculating the potential of the actual operation condition of the zinc oxide arrester under the actual working voltage to obtain the potential value of each zinc oxide resistance card of the zinc oxide arrester, and obtaining the capacitive leakage current value of the zinc oxide resistance card according to the potential difference at the two ends of the zinc oxide resistance card and the capacitance value of the zinc oxide resistance card;
step 5, calculating the resistive leakage current of the zinc oxide resistance card under different resistivities according to the structure and the size of the zinc oxide resistance card and the potential drop of the upper surface and the lower surface of the zinc oxide resistance card;
step 6, calculating the change rate of the resistive leakage current of the zinc oxide arrester according to the capacitive leakage current value and the resistive leakage current value of the zinc oxide resistance chip to obtain the relation between the change condition of the resistive leakage current and the resistivity of the zinc oxide resistance chip;
step 7, judging the piezoresistor to be a failed piezoresistor when the variation rate of the resistive leakage current of the zinc oxide resistor sheet exceeds a threshold value, and calculating the resistive leakage current when the variation rate of the resistive leakage current of the zinc oxide arrester reaches the threshold value, namely the maximum allowable resistive leakage current;
and 8, judging the moisture degree of the zinc oxide arrester according to the real-time monitored resistive leakage current value of the zinc oxide arrester, wherein the larger the resistive leakage current value is, the more serious the zinc oxide arrester is wetted.
2. The method of claim 1, wherein step 3 comprises:
step 3-1, setting grid attributes as relative dielectric constants of all elements of the zinc oxide arrester;
3-2, calculating the potential of the zinc oxide arrester through a potential control equation;
3-3, setting boundary conditions of a three-dimensional entity model of the zinc oxide arrester;
and 3-4, loading the actual working voltage of the zinc oxide arrester.
3. The method according to claim 1, wherein in the step 2, the non-metal parts of the established three-dimensional solid model of the zinc oxide arrester are gridded by adopting a free gridding method, each element of the three-dimensional solid model of the zinc oxide arrester is sequentially gridded from inside to outside, and elements of the same type are divided together.
4. The method of claim 1, wherein in the step 4, the capacitive leakage current value of the zinc oxide resistor sheet is calculated according to the following formula:
Ii＝Ui×Ci×2πf (1)
wherein, IiIndicates the value of capacitive leakage current, U, flowing through the ith zinc oxide resistor disciThe potential difference between two ends of the ith zinc oxide resistance card is shown; ciThe capacitance value of the ith zinc oxide resistance card is shown; and f represents the power frequency.
5. The method according to claim 1, wherein in the step 6, the resistive leakage current fluctuation rate of the zinc oxide resistor sheet is calculated according to the following formula:
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| CN107727993A (en) * | 2017-11-14 | 2018-02-23 | 国网辽宁省电力有限公司电力科学研究院 | The detection means and detection method of DC zinc oxide lighting arrester valve block damp degree |
| CN108693434A (en) * | 2018-08-29 | 2018-10-23 | 深圳天溯计量检测股份有限公司 | A kind of Leakage Current of Zinc-oxide Lightning Arresters test device |
| CN109239540A (en) * | 2018-07-26 | 2019-01-18 | 国网湖南省电力有限公司 | High-voltage arrester defect diagnostic method and voltage distribute measuring device |
| CN109709152A (en) * | 2019-01-30 | 2019-05-03 | 南通大学 | A kind of insulation film measuring system for fA~pA magnitude weak current |
| CN109709151A (en) * | 2019-01-30 | 2019-05-03 | 南通大学 | A kind of thin dielectric film electrical properties measuring system |
| CN111985075A (en) * | 2020-07-03 | 2020-11-24 | 国网山东省电力公司电力科学研究院 | Temperature distribution calculation method and system suitable for zinc oxide arrester |
| CN113419143A (en) * | 2021-05-24 | 2021-09-21 | 广西大学 | Composite insulation state evaluation method based on finite element method and considering sleeve oil paper insulation non-uniform thermal aging effect |
| CN116169657A (en) * | 2023-02-22 | 2023-05-26 | 深圳市拓普泰克技术股份有限公司 | Intelligent photovoltaic lightning protection control system |
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| CN108693434A (en) * | 2018-08-29 | 2018-10-23 | 深圳天溯计量检测股份有限公司 | A kind of Leakage Current of Zinc-oxide Lightning Arresters test device |
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| CN111985075A (en) * | 2020-07-03 | 2020-11-24 | 国网山东省电力公司电力科学研究院 | Temperature distribution calculation method and system suitable for zinc oxide arrester |
| CN111985075B (en) * | 2020-07-03 | 2024-03-26 | 国网山东省电力公司电力科学研究院 | Temperature distribution calculation method and system suitable for zinc oxide lightning arrester |
| CN113419143A (en) * | 2021-05-24 | 2021-09-21 | 广西大学 | Composite insulation state evaluation method based on finite element method and considering sleeve oil paper insulation non-uniform thermal aging effect |
| CN116169657A (en) * | 2023-02-22 | 2023-05-26 | 深圳市拓普泰克技术股份有限公司 | Intelligent photovoltaic lightning protection control system |
| CN116169657B (en) * | 2023-02-22 | 2024-10-01 | 深圳市拓普泰克技术股份有限公司 | Intelligent photovoltaic lightning protection control system |
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