CN112653063A - 10kV overhead line lightning protection method used by matching of coupling ground wire and lightning arrester - Google Patents
10kV overhead line lightning protection method used by matching of coupling ground wire and lightning arrester Download PDFInfo
- Publication number
- CN112653063A CN112653063A CN202011496249.8A CN202011496249A CN112653063A CN 112653063 A CN112653063 A CN 112653063A CN 202011496249 A CN202011496249 A CN 202011496249A CN 112653063 A CN112653063 A CN 112653063A
- Authority
- CN
- China
- Prior art keywords
- ground wire
- lightning
- coupling ground
- coupling
- line
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G7/00—Overhead installations of electric lines or cables
- H02G7/22—Arrangements of earthing wires suspended between mastheads
Abstract
The invention discloses a 10kV overhead line lightning protection method for matching use of a coupling ground wire and a lightning arrester, which comprises the following steps: firstly, considering the influence on the mechanical aspects such as the bearing of a line tower and the like after the coupling ground wires are additionally arranged, and checking the applicability of the coupling ground wires to obtain the installation number of the coupling ground wires. And secondly, under various extreme conditions (ice coating and windage yaw), ensuring that no discharge occurs between the coupling ground wire and the lead at the center of the span, so as to determine the installation position of the coupling ground wire, and further providing a method for testing the lightning resistance level of the 10kV overhead line containing the coupling ground wire. Aiming at the problem that the lightning withstand level is reduced after the coupling ground wire is erected in sections, a lightning protection method for matching the coupling ground wire sections with a lightning arrester is provided, a 10kV overhead line lightning overvoltage simulation calculation model is established by using simulation software, so that the lightning protection effect of matching the coupling ground wire sections with an MOA is tested under the condition that two-phase short circuit of a distribution line does not occur. The lightning protection method can further improve the lightning protection level of the 10kV distribution line and improve the operation reliability of the distribution network on the basis of the existing lightning protection design.
Description
Technical Field
The invention relates to the field of lightning protection of overhead lines of a 10kV power distribution network, in particular to a 10kV overhead line lightning protection method using a coupling ground wire and a lightning arrester (MOA) in a matched mode.
Background
The 10kV distribution line is used as an important connecting part of the power transmission line and the user side, and the safe and stable operation of the distribution line is very important. At present, a typical design is mostly adopted for a 10kV overhead line, and due to the fact that the insulation margin of the overhead line is large, the height of a tower is relatively low, most overhead lines do not need to adopt lightning protection measures, and only measures such as MOA addition and grounding resistance reduction are adopted at distribution equipment such as a distribution transformer and a load switch. The measures can meet the lightning protection requirements of most areas, but the lightning resistance level of some areas with strong lightning activity can not meet the requirements.
In mountainous areas, mining areas and the like with strong lightning activities, lightning protection measures taken by a 10kV overhead line basically mainly include line MOA installation, but the 10kV line MOA is easy to break down to form short circuit points, operation and maintenance workload is increased if the line is installed on the whole line, and later maintenance cost is high. And generally, the tower which is easy to be directly hit by a line needs to be subjected to grounding transformation after the MOA is additionally arranged due to reasons such as terrain and the like, so that the grounding resistance is reduced, the problems of difficult construction and higher cost exist, and the using amount of the MOA needs to be reduced.
The coupling ground wire is a common lightning protection measure in the power transmission line, is arranged at the joint of the lower part of the lead and the tower body, and improves the lightning protection level of the line through the coupling effect between the coupling ground wire and each phase of lead and the shunting effect on lightning current. When setting up coupling ground wire on 10kV overhead distribution lines shaft tower, in order to guarantee distribution lines's safe operation, need emphatically consider the restriction in two respects: (1) under various extreme conditions (icing and windage yaw), it should be ensured that no discharge occurs between the coupled ground line and the conductor at the center of the span; (2) after the coupling ground wire is additionally arranged, the allowable range of the bearing of the tower is not exceeded. In order to ensure that the range of the tower bearing is not exceeded after the coupling ground wire is additionally arranged on the line.
The coupling ground wire has better protective effect to two kinds of thunderbolt forms of response thunder and thunderbolt cross arm, when can bring better lightning protection effect, also has some drawbacks: in the places of crossing roads, rivers, hills and the like, the installation cannot be carried out due to the factor of limiting the height of the ground, and the sectional erection is needed, and the sectional erection cannot play a role in improving the lightning resistance level.
Therefore, 2 lightning protection measures of the coupling ground wire and the lightning arrester are required to be matched for use so as to comprehensively improve the lightning resistance level of the 10kV overhead line.
Disclosure of Invention
The invention provides a 10kV overhead line lightning protection method for matching a coupling ground wire and an MOA (metal oxide arrester), which is used for solving the application method of the coupling ground wire in a 10kV overhead line and providing a method for additionally installing the MOA at the subsection of the coupling ground wire, and is used for solving the problem of reduction of the lightning resistance level of the line caused by the subsection of the coupling ground wire.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
1. the application method of the coupling ground wire in the 10kV overhead line comprises the following steps:
1.1, checking the applicability of the coupling ground wires according to the influence of the coupling ground wires on the mechanical aspects such as the bearing of a line tower and the like after the coupling ground wires are additionally arranged, and obtaining the installation number of the coupling ground wires.
In order to ensure the safe and stable operation of the distribution line after the coupling ground wire is erected, the accounting of the bearing of the tower is particularly important. The vertical load that can increase the shaft tower after setting up coupling ground wire, the vertical load that the shaft tower bore includes: (1) the gravity load of the lead, the coupling ground wire, the insulator string and the hardware fitting; (2) and additional vertical load during installation and maintenance comprises the gravity load of workers and tools. Respectively calculating the vertical load value G after considering the icingDkDesign value G of vertical loadDWherein
GDk＝nγ1ALV+GJ+nγ2ALV+GJ(K-1) (1)
GD＝γGnγ1ALV+γGGJ+γQnγ2ALV+γGGJ(K-1)+Gf (2)
In the formulas (1) and (2), n is the number of the conducting wires; l isVVertical span for tower, m: gamma ray1、γ2Respectively, the vertical specific load before and after ice coating, N/(m.mm)2) (ii) a K is the icing coefficient, and when the designed icing thickness is 5mm, 1.075 is taken; gfFor additional vertical load during installation and maintenance
If G isDk＜GDAnd the requirement of minimum margin can be met, and the bearing requirement of the tower can be met after the coupling ground wire is erected.
For typical arrangement of a tower type and materials of a 10KV line tower, generally, a single coupling ground wire is preferably additionally arranged on the 10KV line tower. In the invention, the application method of the coupling ground wire in the 10KV overhead line is a single coupling ground wire. As shown in fig. 1, the grounding device comprises a coupling grounding wire (1), wherein the coupling grounding wire (1) is arranged below a lower conductor cross arm (2), an anchor ear (3) is arranged on the coupling grounding wire (1), and the coupling grounding wire (1) is fixed through the anchor ear (3) and is connected with a tower (4).
1.2 determination of the installation position of the coupled ground wire
The installation position of the coupling ground wire adopted by the invention in a 10kV overhead line tower is shown in figure 1, the coupling ground wire is required to be positioned below a wire cross arm (2), an anchor ear (3) is arranged on the coupling ground wire (1), the coupling ground wire (1) is fixed through the anchor ear (3) and is connected with the tower (4), and the key point is to determine the distance P below the cross arm.
The distance between the coupling ground wire and the conducting wire must be greater than a certain safety distance, and the distance between the conducting wire and the ground wire in the center of the span must meet the requirement
S≥0.012L+1 (3)
In the formula (3), S is the distance between the coupling ground wire and the conducting wire at the center of the span; and L is the span of the line.
The distance S between the ground and the conductor at the center of the span can be determined from equation (3). The overhead conductor and the coupling ground wire have certain sag, and the sag size is related to factors such as temperature, ice coating and the like. After selecting the bare conductor, the insulated conductor and the coupling ground wire with specific applicable models, the maximum sag H of various wire types under different spans under extreme conditions is found. And finally, determining the suspension position P of the coupling ground wire according to the geometrical position relation by the span central distance S and the maximum sag H.
According to the method, the installation position of the 10KV line pole tower coupling ground wire is obtained. For a 10kV overhead bare conductor line, hanging a coupling ground wire at a position 4.2m below the lowest cross arm, namely P is 4.2 m; for a 10kV overhead insulated conductor line, a coupling ground wire is hung at a position 5.3m below the lowest cross arm, namely P is 5.3 m. At this time, the distance between the lower bare conductor and the coupling ground wire at the center of the span is 2.13m, the distance between the insulated conductor and the coupling ground wire is 2.03m, and the distance can meet the requirement of the distance between the conductor and the coupling ground wire that discharge does not occur under various extreme conditions.
2. The invention also provides a simulation calculation method for testing the lightning resistance level of a 10kV overhead line containing a coupling ground wire, which comprises the following steps:
in the test, ATP-EMTP simulation software is adopted to establish a 10kV overhead line lightning overvoltage simulation calculation model, and 10kV single-circuit and double-circuit power distribution line simulation models are respectively established in ATP-EMPT. The device comprises 9-base towers, wherein the span between lines is 80m, the leftmost side of the lines is a 10kV three-phase alternating-current power supply, an insulator flashover model is simplified to be replaced by a voltage-controlled switch, and the 50% impact breakdown voltage of the insulator is 139 kV. A JMARTI model which can reflect frequency characteristics in LCC is selected as a model of a bare conductor and a coupling ground wire in ATP-EMTP, and a single-core cable model is selected as an insulated conductor model to replace the model.
2 typical line arrangements of single-loop triangular and double-loop linearly arranged conductors are respectively tested, and the rule of influence on the lightning resistance level of a 10kV overhead bare conductor and an insulated conductor after a coupling ground wire is erected in 3 lightning strike modes of inducing lightning overvoltage, lightning strike overhead lines and lightning strike cross arms.
Because the neutral point in the 10kV power distribution system adopts a non-effective grounding mode, the circuit can be tripped immediately only when two-phase or three-phase short circuit occurs. Therefore, the defined lightning resistant level is the minimum current amplitude value for enabling the distribution line to generate two-phase or three-phase line insulation flashover when the line is struck by lightning. In the simulation test, a smaller current is applied firstly, the amplitude of the lightning current is gradually increased, and the insulator flashover condition is observed. When 2-phase or 3-phase insulator flashover occurs, the corresponding minimum lightning current amplitude is recorded as the lightning resistance level of the line.
The line shape, tower shape and span in the 10kV overhead line are taken as calculation examples, and the effect of the influence of the whole line additionally provided with the coupling ground wire on the lightning resistance level of the line is obtained. For the single-circuit triangular arrangement line, after the coupling ground wire is erected, the lightning resistance level of the bare conductor line is improved by 86.3 percent to the maximum extent, and the lightning resistance level of the insulated conductor line is improved by 90.8 percent to the maximum extent; for the double-circuit straight line arrangement line, after the coupling ground wire is erected, the lightning resistance level of the bare conductor line is improved by 79.9% to the maximum extent, and the lightning resistance level of the insulated conductor line is improved by 112.7% to the maximum extent.
After the coupling ground wire is used in a segmented mode, the lightning withstand level of the lightning stroke cross arm is the same as that when the coupling ground wire is not erected, and the lightning withstand level of the induction lightning is reduced along with the increase of the breaking range of the coupling ground wire. When the coupling ground wires are erected at 5-base tower intervals, the induced lightning resistant level is equivalent to the lightning resistant level without the coupling ground wires.
3. The invention also provides a method for matching use and effect test with the MOA at the coupling ground wire subsection of the 10kV overhead line, which comprises the following steps:
the MOA has a direct lightning protection function, so the invention mainly aims at two lightning strike modes of induction lightning and lightning strike cross arm. A single-circuit 10kV overhead distribution line simulation model is built in the ATP-EMTP, wherein the model comprises a 13-base tower, the MOA is simulated by adopting a nonlinear resistor, and an insulator, a lead and a coupling ground wire model are the same as those of the upper section.
In the simulation, the coupling ground wires between the No. 6-8 tower and the No. 5-9 tower are disconnected, and the schematic diagram is shown in FIG. 2 by taking the disconnection of the coupling ground wires between the No. 5-9 tower as an example. In consideration of the most serious situation, the lightning stroke point of the direct lightning is arranged on the cross arm of the No. 7 tower, and the inductive lightning is arranged 100m away from the No. 7 tower. And (4) carrying out simulation calculation to obtain lightning resistance levels when MOAs are arranged at different phases of 1-4 base towers on the left and right of No. 7 towers. In the simulation test, a smaller current is applied firstly, the amplitude of the lightning current is gradually increased, and the insulator flashover condition is observed. When 2-phase or 3-phase insulator flashover occurs, the corresponding minimum lightning current amplitude is recorded as the lightning resistance level of the line.
Through simulation calculation, fig. 3 and 4 respectively show the change rule of lightning withstand level when the sectional coupling ground wire is matched with B, C-phase MOA and three-phase MOA during lightning stroke cross arm. Fig. 5 and 6 are respectively the change rule of lightning withstand level when the induction lightning time subsection coupling ground wire is matched with B, C phase and three-phase MOA.
Therefore, (1) when the cross arm is struck by lightning, the MOA is continuously installed at the coupling ground wire subsection, so that the problem of lightning resistance level reduction caused by the subsection erection of the coupling ground wire can be solved. The lightning resistance level of the B, C-phase MOA installation mode is slightly higher than that of a three-phase MOA installation mode, and the B, C-phase MOA installation mode has better economic benefit; (2) under the action of an induction thunder, when the disconnection range of the coupling ground wire is small (between No. 6 and No. 8 towers), the lightning protection effect of the B, C phase MOA is almost the same as that of the three-phase MOA, and when the disconnection range of the coupling ground wire is expanded (between No. 5 and No. 9 towers), the matching effect of the three-phase MOA and the coupling ground wire is obviously better than that of the B, C two-phase installation.
Therefore, when coupling towers with the ground wire segment spacing of 3 bases and less, the invention provides that the MOA is installed on B, C phases (the highest phase and the side phase) of the step-by-step tower at the segment spacing (comprising 2 ends); when the tower with the ground wire subsection interval of more than 3 bases is coupled, the MOA is installed on the step-by-step tower three-phase at the subsection interval (comprising 2 ends).
The invention has the following beneficial effects:
the accounting method and the specific installation mode of the applicability of the coupling ground wire in the 10kV overhead line consider the sag change caused by extreme weather such as ice coating and the like. The optimal installation position is designed, and the installation of the device can be safely, accurately and quickly guided.
The test method of the invention can test that: for the single-circuit triangular arrangement line, after the coupling ground wire is erected, the lightning resistance level of the bare conductor line is improved by 43.2 percent to the maximum extent, and the lightning resistance level of the insulated conductor line is improved by 74.5 percent to the maximum extent; for the double-circuit straight line arrangement line, after the coupling ground wire is erected, the lightning resistance level of the bare conductor line is improved by 44.7% to the maximum extent, and the lightning resistance level of the insulated conductor line is improved by 54.5% to the maximum extent.
After the coupling ground wire subsection is matched with the MOA for use, overvoltage at two ends of the insulator of the whole line can be greatly reduced, and the problem of lightning resistance level reduction caused by the coupling ground wire subsection is effectively solved.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic structural diagram of a tower of a 10kV single-circuit overhead line additionally provided with a coupling ground wire according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram of tower erection subsection coupling ground wires of No. 5-9 in the preferred embodiment of the invention.
FIG. 3 is a schematic diagram of the change rule of the lightning withstand level of the combination of the segment coupling ground wire and B, C-phase MOA when the cross arm is struck by lightning in the preferred embodiment of the invention;
FIG. 4 is a schematic diagram of the lightning resistant level change rule of the combination of the sectional coupling ground wire and the three-phase MOA when the cross arm is struck by lightning in the preferred embodiment of the invention;
FIG. 5 is a schematic diagram of the variation rule of lightning withstand level of the combination of the induction lightning time-division coupling ground wire and B, C-phase MOA according to the preferred embodiment of the invention;
FIG. 6 is a schematic diagram of the lightning withstand level variation law of the matching of the inductive lightning time-division coupling ground wire and the three-phase MOA according to the preferred embodiment of the invention;
FIG. 7 is a schematic diagram of the voltage waveforms across the insulator when the single-circuit bare conductor is unprotected during lightning induction in accordance with the preferred embodiment of the present invention;
FIG. 8 is a schematic diagram showing voltage waveforms across the insulator when a coupling ground is installed on a single-circuit bare conductor in induction of lightning in accordance with a preferred embodiment of the present invention;
FIG. 9 is a schematic diagram of the voltage waveforms across the insulator when the double-circuit bare conductor is unprotected during lightning induction in accordance with the preferred embodiment of the present invention;
FIG. 10 is a schematic diagram showing the voltage waveforms across the insulator when a coupled ground wire is installed on a double-circuit bare conductor in an inductive lightning strike according to the preferred embodiment of the present invention;
the reference numerals in the figures denote:
1. coupling a ground wire; 2. a cross arm; 3. a metal hoop; 4. a pole tower.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
1. The application method of the coupling ground wire in the 10kV overhead line comprises the following steps:
1.1, checking the applicability of the coupling ground wires according to the influence of the coupling ground wires on the mechanical aspects such as the bearing of a line tower and the like after the coupling ground wires are additionally arranged, and obtaining the installation number of the coupling ground wires.
The vertical load values and the vertical load design values after different numbers of coupling ground wires are erected on the single-circuit bare conductor and the double-circuit bare conductor and the insulated conductor are obtained by calculation according to the formula (1) and the formula (2), and the calculation results are shown in the table 1.
TABLE 1 vertical load of tower
Therefore, the vertical load values after the single coupling ground wire is erected are all smaller than the vertical load design value, the margin requirement is met, and the bearing requirement of the tower can be met. If 2 coupling ground wires are arranged, the vertical load values are all larger than the vertical load design value, and the requirements of the line tower in the aspect of bearing cannot be met. Therefore, the coupled ground wires of the invention adopt 1 wire.
1.2 determination of the installation position of the coupled ground wire
A typical span of a 10kV distribution line is 80m, which can be obtained from equation (3): the distance S between the conductor and the ground at the center of the span should be greater than 1.96 m. Taking a typical linear selection standard of a 10kV line as an example, a GJ-25 steel strand is adopted as a coupling ground wire, a JL/G1A-70/10 steel-cored aluminum strand is adopted as a bare wire, a JKLYJ-10/70 aluminum-cored crosslinked polyethylene insulated overhead cable is adopted as an insulated wire, and specific parameters are shown in Table 2.
Meter 210 kV distribution line conductor parameters
The calculation method can obtain that the coupling ground wire is hung 4.2m under the single-circuit bare wire cross arm and the double-circuit bare wire cross arm, and 5.3m under the single-circuit insulated wire cross arm and the double-circuit insulated wire cross arm, the distance between the lower bare wire and the coupling ground wire at the span center is 2.13m, the distance between the insulated wire and the coupling ground wire is 2.03m, and the distance can meet the requirement of the distance between the wire and the coupling ground wire that no discharge occurs under various extreme conditions.
2. Lightning protection effect of additional coupling ground wire of 10kV distribution line
A10 kV single-circuit and double-circuit power distribution line simulation model is respectively built in the ATP-EMTP, wherein the model comprises 9-base towers, the span between the lines is 80m, the leftmost side is a 10kV three-phase alternating-current power supply, an insulator flashover model is simplified to be replaced by a voltage-controlled switch, and the 50% impact breakdown voltage of the insulator is 139 kV. A JMARTI model which can reflect frequency characteristics in LCC is selected as a model of a bare conductor and a coupling ground wire in ATP-EMTP, and a single-core cable model is selected as an insulated conductor model to replace the model. The wire types and parameters are shown in table 2.
The form of lightning strikes that cause tripping of 10kV distribution lines is mainly three cases: the induction thunder and lightning stroke leads and the lightning stroke pole tower cross arm. The common conductors of the 10kV distribution line are divided into bare conductors and insulated conductors, and the tower-shaped distribution line is divided into a single-loop line and a multi-loop line on the same tower. Thus, 12 different typical lightning strike scenarios are set for a 10kV distribution line.
2.1 Effect of coupling ground wire on lightning resistance level of 10kV bare conductor
2.1.1 induced lightning level
In the simulation test, an induction thunderstorm point is arranged at one end of a line and is 100m away from a first base tower. A smaller current is applied first, the magnitude of the lightning current is gradually increased, and the insulator flashover is observed. When 2-phase or 3-phase insulator flashover occurs, the corresponding minimum lightning current amplitude is recorded as the induced lightning withstand level of the line.
(1) Single-circuit line
When the amplitude of the induced lightning current is gradually increased to 37.2kA on the line, two-phase flashover occurs on the line, the voltage waveform of the end of the insulator 2 terminal when the single-circuit triangular arrangement bare conductor is unprotected is shown in figure 7, and the level of the induced lightning resistance when the coupling ground wire is not erected is 37.2 kA.
When a coupling ground wire is erected, according to the same method, when an induction lightning with the amplitude of 69.3kA acts on the line, two-phase flashover occurs on the line, and the voltage waveform of the end of the insulator 2 is shown in figure 8. Due to the coupling effect of the coupling ground wire, overvoltage at two ends of the insulator string can be greatly reduced, and the lightning resistance level is improved by 86.3 percent after the coupling ground wire is erected.
(2) Double-circuit line
When the double-circuit six-phase line is simultaneously subjected to an induced lightning with the amplitude of 36.9kA, a three-phase flashover occurs in the first circuit, and the voltage waveform of the terminal of the insulator 2 when the double-circuit triangular arrangement bare conductor is unprotected is shown in fig. 9. And the lightning resistance level when the coupling ground wire is not erected is 36.9kA due to no protection effect of the coupling ground wire.
When a coupling ground wire is erected, according to the same method, when the double-circuit six-phase line and the coupling ground wire are simultaneously subjected to induced lightning with the amplitude of 66.4kA, the first circuit is just subjected to three-phase flashover, and the voltage waveform of the end of the insulator 2 is shown in fig. 10. Compared with the non-erected coupling ground wire, the induced lightning withstand level after the erection of the coupling ground wire is improved by 79.9 percent.
2.1.2 lightning-resistant level when lightning strikes cross arm of tower (counterattack)
When the tower cross arm is struck by lightning, a direct lightning strike point is arranged on the tower cross arm, the amplitude of lightning is gradually increased, and the insulator flashover condition is observed. When 2-phase or 3-phase insulator breakdown occurs, the corresponding maximum lightning current amplitude is the lightning stroke cross arm lightning-resistant level of the line. The lightning withstand levels for single and double circuit lines struck by lightning on the wire are summarized in tables 3 and 4.
2.1.3 lightning withstand level when lightning strikes to a conductor
For the tower with single-circuit triangular arrangement, the middle phase is a B-phase wire. For a tower with double-circuit straight arrangement, the highest phase is also the B-phase conductor. Therefore, only direct lightning strikes on the B-phase conductor are considered at this time, so that the lightning resistance level in each case is obtained, and the method for obtaining the lightning resistance level is the same as the above method. The lightning withstand levels for single and double circuit lines struck by lightning on the wire are summarized in tables 3 and 4.
2.1.4 simulation result analysis of lightning resistance level of 10kV bare conductor
Through the simulation test, the lightning resistance level test results of the single-circuit bare conductor and the double-circuit bare conductor are collated in tables 3 and 4.
TABLE 3 lightning resistance level of single-circuit bare conductor
TABLE 4 lightning resistance level of double-circuit bare conductor
As can be seen from tables 3 and 4, after the coupling ground wire is erected, the lightning resistance horizontal effect is obvious when bare conductor induced lightning and lightning strike on the cross arm of the tower are improved. When the inductive lightning acts on the line, the inductive lightning withstand level of the single-loop bare conductor and the double-loop bare conductor can be respectively improved by 86.3 percent and 79.9 percent after the coupling ground wire is erected. When the tower cross arm is struck by lightning, the counterattack lightning-resistant level of the single-circuit bare conductor and the double-circuit bare conductor after the coupling ground wire is erected can be respectively improved by 36.2 percent and 44.7 percent.
However, the improvement effect on the lightning resistance level when the phase conductor is directly struck is not obvious, and the lightning resistance level of the lightning conductor of the single-circuit bare conductor and the lightning conductor of the double-circuit bare conductor can be respectively improved by 4 percent and 13.6 percent after the coupling ground wire is erected.
2.2 Effect of coupling ground wire on lightning resistance level of 10kV insulated conductor
Aiming at a 10kV overhead insulated wire, in an insulated wire simulation model, the lightning resistance level of a front line and a rear line of a coupling ground wire is erected under three conditions of direct-lightning-stroke cross arms, direct-lightning-stroke wires and induction lightning when different wire arrangement modes are calculated according to the same method in the upper section. The minimum current amplitude of the distribution line with two-phase or three-phase line insulation flashover is also taken as the lightning resistance level.
TABLE 5 lightning resistance level of single-loop insulated conductor
TABLE 6 lightning resistance level of double-circuit insulated conductor
As can be seen from tables 5 and 6, after the coupling ground wire is erected, the coupling ground wire has the obvious effect of improving the lightning resistance level of the 10kV insulated wire when an induction lightning strikes the cross arm of the tower and the lightning resistance level of the tower. When the induction thunder acts on the insulated conductor, the lightning resistance level of the induction thunder to the single-loop insulated conductor and the double-loop insulated conductor can be respectively improved by 90.8 percent and 112.7 percent after the coupling ground wire is erected. When the tower cross arm is struck by lightning, the counterattack lightning-resistant level of the single-circuit and double-circuit insulated conductors after the coupling ground wire is erected can be respectively improved by 74.5 percent and 53.2 percent.
However, the improvement effect of the lightning resistance level when the insulated conductor is directly struck is still not obvious, and the lightning resistance level of the lightning conductor of the single-circuit bare conductor and the double-circuit bare conductor after the coupling ground wire is erected can be improved by 7 percent and 13.6 percent respectively.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
3. The invention also provides a method for testing the MOA lightning protection effect installed at the subsection of the coupling ground wire of the 10kV overhead line, which comprises the following steps:
3.1 construction of simulation test platform
A single-circuit 10kV overhead distribution line simulation model is built in the ATP-EMTP, wherein 13-base towers are included, the span between lines is 80m, the left side is a 10kV three-phase alternating-current power supply, an insulator flashover model is simplified to be replaced by a voltage-controlled switch, and 50% of the impact breakdown voltage of the insulator is 139 kV. A JMARTI model capable of reflecting frequency characteristics in LCC is selected as a model of a bare conductor and a coupling ground wire in ATP-EMTP, and the types and parameters of the conductors are shown in Table 2.
And 3.2, testing the limiting effect of the MOA arranged at the coupling ground wire subsection of the 10kV overhead line on the lightning overvoltage.
Taking a single-loop triangular arrangement bare conductor as an example, a model of a 10kV distribution line for erecting a single coupling ground wire is simulated in simulation software. In the simulation, a smaller current is applied firstly, the amplitude of the lightning current is gradually increased, and the insulator flashover condition is observed. When 2-phase or 3-phase insulator flashover occurs, the corresponding minimum lightning current amplitude is recorded as the lightning resistance level of the line. Through simulation calculation, the lightning withstand levels under different coupling ground wire erection modes under the conditions of lightning cross arms and induced lightning are obtained, as shown in table 7.
TABLE 7 lightning resistance level under different coupling ground wire erection modes
Therefore, when the coupled ground wire spacing 5-base tower is erected, the lightning stroke cross arm and the induced lightning withstand level are equivalent to the lightning withstand level without the coupled ground wire, and therefore only two conditions of the coupling ground wire spacing 3 base and the spacing 5 base are considered in the simulation test.
3.2.1 lightning protection effect of using sectionally coupled ground wire and MOA in cooperation during cross arm lightning stroke
(1) MOA B, C-phase (top phase and side phase) mounting mode
In order to verify the lightning protection effect of the section coupling ground wire used in cooperation with B, C-phase MOA during lightning stroke of the cross arm, according to the simulation model, two conditions of a spacing 3 base and a spacing 5 base of the coupling ground wire are considered respectively, a lightning stroke point is arranged on the cross arm of a No. 7 tower, a small current is applied firstly, the amplitude of the lightning current is increased gradually, and the insulator flashover condition is observed. When 2-phase or 3-phase insulator flashover occurs, the corresponding minimum lightning current amplitude is recorded as the lightning resistance level of the line.
FIG. 3 is a lightning resistant level change rule of matching of a segment coupling ground wire and B, C phase MOA during lightning stroke cross arm. The simulation result shows that (1) when the cross arm is struck by lightning, only the MOA is arranged on the tower of the easy-to-strike pole, and when the MOA installation density does not extend to the tower at the subsection of the coupling ground wire, the lightning protection level of the subsection-arranged coupling ground wire is not as high as that of the whole-line arrangement; (2) when the MOA installation density extends to the tower at the disconnection position of the coupling ground wire, the overall lightning resistance level of the line is slightly superior to that of the coupling ground wire erected on the whole line.
(2) MOA three-phase mounting mode
According to the same method, the lightning protection effect of the section coupling ground wire and the three-phase MOA in cooperation is verified when the cross arm is struck by lightning. FIG. 4 is a lightning resistant horizontal change rule of the matching of the sectional coupling ground wire and the three-phase MOA during lightning stroke of the cross arm.
The simulation result shows that (1) when the cross arm is struck by lightning, the lightning protection effect of the sectionally-coupled ground wire and the three-phase MOA after being matched for use is obviously superior to that of the three-phase MOA only; (2) after the MOAs are continuously installed at the subsection, the lightning protection effect of the subsection coupling ground wire used in cooperation with the three-phase installation MOAs is approximately the same as the effect of the whole-wire erection coupling ground wire used in cooperation with the MOAs.
In conclusion, the lightning resistance level of the B, C-phase MOA mode is slightly higher than that of the three-phase MOA mode, and the B, C-phase MOA mode has better economic benefit. Therefore, for lightning stroke cross arm, B, C-phase MOA is continuously arranged at the coupling ground wire subsection, so that better lightning protection effect is achieved.
3.2.2 lightning protection effect of matching use of inductive lightning time subsection coupling ground wire and MOA
The inductive lightning adopts MODELS inductive lightning module in ATP, and the lightning current channel is assumed to be vertical to the ground, and the lightning return speed is 3 multiplied by 108m/s, and soil resistivity of 1000. omega. m. In the simulation, the coupling ground wires between the No. 6-8 tower and the No. 5-9 tower are also disconnected, and the lightning stroke induction point is arranged at a position 100m away from the No. 7 tower in consideration of the most serious condition.
(1) MOA B, C-phase (top phase and side phase) mounting mode
And arranging lightning stroke points of the induced lightning at a distance of 100m from the No. 7 tower to obtain lightning resistant levels under MOA installed on B, C phases of 1-4 base towers on the left and right of the No. 7 tower. FIG. 5 is a lightning resistant level change rule of the inductive lightning time sectional coupling ground wire matched with B, C-phase MOA.
The simulation result shows that (1) aiming at the induction lightning, when the section range of the coupling ground wire is small (between No. 6-8 towers), the lightning protection effect is the same as that when the coupling ground wire is erected on the whole line when the B, C phases of the three base towers on the left and right of the lightning-struck tower are provided with MOAs; (2) when the sectional range of the coupling ground wire is large (between No. 5-9 towers), the lightning protection effect of the coupling ground wire is still not as good as that of the coupling ground wire erected on the whole wire after the installation density of B, C-phase MOAs is gradually increased.
(2) MOA three-phase mounting mode
And verifying the lightning protection effect of the section coupling ground wire under the induction lightning and the three-phase MOA in cooperation according to the same method. FIG. 6 is a lightning resistant horizontal change rule of the matching of the sectional coupling ground wire and the three-phase MOA during lightning stroke of the cross arm.
The simulation result shows that (1) for the induction thunder, when the MOA installation density is equal to or less than two bases on the left and right of a lightning strike tower, the larger the subsection range of the coupling ground wire is, and the lower the lightning withstand level of the induction thunder is. Under the installation density, the lightning protection effect is not as good as that of the whole line erection coupling ground wire; (2) when the MOA is installed in the three phases of the three-base-tower on the left and right of the lightning-struck tower, namely the three-phase MOA is continuously installed at the subsection of the coupling ground wire, the three-phase MOA is also simultaneously installed on the adjacent base-tower at the subsection, and the lightning protection effect is the same as that when the coupling ground wire is erected on the whole wire at the moment.
In conclusion, the lightning protection method for the 10kV overhead line by matching the coupling ground wire with the lightning arrester has the advantage that the lightning protection effect is obviously improved compared with the lightning protection effect only provided with MOA under two lightning stroke forms of the lightning stroke cross arm and the induced lightning stroke. When the tower is coupled with the ground wire segment interval of 3 bases and less, the MOA is installed on B, C phases (the highest phase and the side phase) of the step-by-step tower at the segment interval (including 2 ends); when the coupled ground wire is coupled with towers with the segmented interval of more than 3 bases, MOAs are installed in three phases of the step-by-step towers at the segmented interval (comprising 2 ends). The problem of lightning withstand level reduction caused by coupling ground wire segments can be effectively solved.
Claims (7)
1. A10 kV overhead line lightning protection method for coupling a ground wire and a lightning arrester (MOA) is characterized by comprising the following steps: considering the influence on the mechanical aspects such as the bearing of a line tower and the like after the coupling ground wires are additionally arranged, and checking the applicability of the coupling ground wires to obtain the installation number of the coupling ground wires; under extreme conditions (ice coating and windage yaw), ensuring that no discharge occurs between the coupling ground wire and the lead at the center of the span, thereby determining the installation position of the coupling ground wire and further providing a method for testing the lightning resistance level of a 10kV overhead line containing the coupling ground wire; aiming at the problem that the lightning withstand level is reduced after the coupling ground wire is erected in sections, a lightning protection method for matching the coupling ground wire sections with the lightning arrester is provided, a 10kV overhead line lightning overvoltage simulation calculation model is established by using simulation software, so that the lightning protection effect of matching the coupling ground wire sections with the MOA is tested under the condition that two-phase short circuit of a distribution line does not occur.
2. The lightning protection method for the 10kV overhead line used by matching the coupling ground wire with the MOA according to claim 1, wherein the applicability accounting method for the coupling ground wire comprises the following steps:
respectively calculating the vertical loads G of the iced conductor, the coupling ground wire, the insulator string and the hardware fittingDkCalculating the design value G of the vertical load of the tower by considering the additional vertical load and the ice coating influence during installation and maintenanceD. Finally comparing the vertical load value G after the coupling ground wire is erectedDkAnd vertical load design value GDIf G isDk＜GDAnd the bearing requirement of the tower can be met after the coupling ground wire is erected.
3. The 10kV overhead line lightning protection method used by matching the coupling ground wire with the MOA according to claim 2, wherein the vertical load value G of the tower after the coupling ground wire is erectedDkAnd vertical load design value GDCalculated by the following formula:
GDk＝nγ1ALV+GJ+nγ2ALV+GJ(K-1) (1)
GD＝γGnγ1ALV+γGGJ+γQnγ2ALV+γGGJ(K-1)+Gf (2)
in the formulas (1) and (2), n is the number of the conducting wires; l isVVertical span for tower, m: gamma ray1、γ2Respectively, the vertical specific load before and after ice coating, N/(m.mm)2) (ii) a K is the icing coefficient; gfFor additional vertical load during installation and maintenance.
Aiming at typical settings of tower types and materials of 10KV line towers, according to the verification of the calculation method, the application method of the coupling ground wire in the 10KV overhead line provided by the invention is a single coupling ground wire.
4. The lightning protection method for the 10kV overhead line used by the coupling ground wire and the MOA in cooperation is characterized in that the determination of the installation position of the coupling ground wire comprises the following steps:
in order to ensure the safe operation of the distribution line, when the coupling ground wire is erected on a 10kV overhead distribution line tower, the fact that the discharge does not occur between the coupling ground wire and the conducting wire at the center of a span under various extreme conditions (ice coating and windage yaw) needs to be considered, so that the distance S between the coupling ground wire and the conducting wire needs to be larger than a certain safe distance, and the distance between the conducting wire and the ground wire at the center of the span needs to meet the requirement that the distance between the conducting wire and the ground wire at the center of
S≥0.012L+1 (3)
In the formula (3), S is the distance between the coupling ground wire and the conducting wire at the center of the span; and L is the span of the line.
The distance S between the ground and the conductor at the center of the span can be determined from equation (3). The overhead conductor and the coupling ground wire have certain sag, and the sag size is related to factors such as temperature, ice coating and the like. After selecting the bare conductor, the insulated conductor and the coupling ground wire with specific applicable models, the maximum sag H of various wire types under different spans under extreme conditions is found. And finally, determining the suspension position P of the coupling ground wire according to the geometrical position relation by the span central distance S and the maximum sag H.
According to the calculation method, for a 10kV overhead bare conductor line, a coupling ground wire is hung at a position 4.2m below the lowest cross arm, namely P is 4.2 m; for a 10kV overhead insulated conductor line, a coupling ground wire is hung at a position 5.3m below the lowest cross arm.
5. The lightning protection and test method for the 10kV overhead line used by matching the coupling ground wire with the MOA according to claim 1, characterized in that a method for simulation test of the lightning withstand level of the 10kV overhead line containing the coupling ground wire is used, a 10kV distribution line overvoltage simulation model containing the coupling ground wire is built, and the maximum lightning current amplitude of the distribution line, namely the lightning withstand level of the 10kV overhead line, is calculated under the condition that two-phase short circuit of the distribution line does not occur.
6. The lightning protection method for the 10kV overhead line used by matching the coupling ground wire with the MOA according to claim 1, wherein the MOA is specifically installed at the coupling ground wire segment in a manner that:
(1) aiming at two lightning stroke forms of an induction lightning and a lightning stroke cross arm, when a tower is coupled with a ground wire section interval of 3 bases and within, an MOA is suggested to be installed on B, C phases (the highest phase and the side phase) of a step-by-step tower at the section interval (including 2 ends);
(2) when coupling towers with ground wire segment spacing of more than 3 bases, the MOA is recommended to be installed in three phases of the step-by-step towers at the segment spacing (including 2 ends).
7. The lightning protection method for the 10kV overhead line used by matching the coupling ground wire with the MOA according to claim 1, wherein the method for simulating and testing the matching use effect of the sectional coupling ground wire and the MOA comprises the following steps:
a simulation calculation model of the lightning overvoltage of the 10kV overhead line containing the subsection coupling ground wire is established in simulation software, and the lightning protection effect of the MOA installation mode of the subsection of the 10kV overhead line coupling ground wire is tested under the condition that 2 lightning strike modes of lightning overvoltage induction and lightning strike cross arm are adopted, and two-phase short circuit of the distribution line is avoided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011496249.8A CN112653063B (en) | 2020-12-17 | 2020-12-17 | Lightning protection method for 10kV overhead line used by matching coupling ground wire and lightning arrester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011496249.8A CN112653063B (en) | 2020-12-17 | 2020-12-17 | Lightning protection method for 10kV overhead line used by matching coupling ground wire and lightning arrester |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112653063A true CN112653063A (en) | 2021-04-13 |
| CN112653063B CN112653063B (en) | 2022-07-29 |
Family
ID=75354640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011496249.8A Active CN112653063B (en) | 2020-12-17 | 2020-12-17 | Lightning protection method for 10kV overhead line used by matching coupling ground wire and lightning arrester |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112653063B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007209173A (en) * | 2006-02-06 | 2007-08-16 | Hokuriku Electric Power Co Inc:The | Equipment for protecting lightning and surge damage of overhead electric line, and its construction method |
| CN104682304A (en) * | 2015-02-03 | 2015-06-03 | 国网上海市电力公司 | Suburb 10kV power distribution line differentiated lightning-protection method |
| CN105098694A (en) * | 2015-08-24 | 2015-11-25 | 国网天津静海供电有限公司 | Overhead lightning line erection method based on typical design of power distribution network |
| CN105243176A (en) * | 2015-08-31 | 2016-01-13 | 华南理工大学 | Graphic analysis method for optimization configuration of lightning arrester on 110kV/220kV power transmission line |
| CN106451308A (en) * | 2016-11-17 | 2017-02-22 | 国网上海市电力公司 | 35kv/10kv common-tower distribution line lightning protection device |
| CN112054459A (en) * | 2020-07-31 | 2020-12-08 | 广东电网有限责任公司广州供电局 | Lightning protection method for distribution line |
-
2020
- 2020-12-17 CN CN202011496249.8A patent/CN112653063B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007209173A (en) * | 2006-02-06 | 2007-08-16 | Hokuriku Electric Power Co Inc:The | Equipment for protecting lightning and surge damage of overhead electric line, and its construction method |
| CN104682304A (en) * | 2015-02-03 | 2015-06-03 | 国网上海市电力公司 | Suburb 10kV power distribution line differentiated lightning-protection method |
| CN105098694A (en) * | 2015-08-24 | 2015-11-25 | 国网天津静海供电有限公司 | Overhead lightning line erection method based on typical design of power distribution network |
| CN105243176A (en) * | 2015-08-31 | 2016-01-13 | 华南理工大学 | Graphic analysis method for optimization configuration of lightning arrester on 110kV/220kV power transmission line |
| CN106451308A (en) * | 2016-11-17 | 2017-02-22 | 国网上海市电力公司 | 35kv/10kv common-tower distribution line lightning protection device |
| CN112054459A (en) * | 2020-07-31 | 2020-12-08 | 广东电网有限责任公司广州供电局 | Lightning protection method for distribution line |
Non-Patent Citations (1)
| Title |
|---|
| 杨鑫等: "基于正态分布的带串联间隙避雷器间隙距离的确定方法", 《电磁避雷器》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112653063B (en) | 2022-07-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Chowdhuri et al. | Parameters of lightning strokes: A review | |
| Visacro et al. | The use of underbuilt wires to improve the lightning performance of transmission lines | |
| CN110445082B (en) | Single-phase installation structure of parallel gap of 10kV distribution line and test method thereof | |
| CN102967785A (en) | Method for evaluating lightning protection performance of high-speed railway traction network | |
| CN111740349B (en) | Overhead ground wire configuration method for power distribution network and overhead ground wire | |
| Grebovic et al. | Lightning outage performance of power distribution line located in Mountain Lovćen area | |
| CN112653063B (en) | Lightning protection method for 10kV overhead line used by matching coupling ground wire and lightning arrester | |
| Banjanin | Line arresters and underbuilt wire application in lightning protection of 110 kV and 220 kV overhead transmission lines | |
| Piantini et al. | Lightning interaction with medium-voltage overhead power distribution systems | |
| Mikropoulos et al. | Effects of simulation models of overhead transmission line basic components on backflashover surges impinging on GIS substations | |
| CN111431129B (en) | Transmission line without lightning conductor | |
| CN109815593B (en) | Analysis method for coupling propagation mechanism of successive faults of distribution network | |
| CN111666662B (en) | Single-phase collinear installation method for parallel connection gap of 10kV overhead line | |
| Kusuma et al. | Studying of lightning surge transient effect on 500 kV quadruple circuit transmission line | |
| CN112054459A (en) | Lightning protection method for distribution line | |
| CN110336241A (en) | A kind of lightning-protection method and device of the intelligent power distribution net in more overcast and rainy areas | |
| Zhou et al. | Research on Optimal Configuration of Line Lightning Arrester Considering Terrain and Flashover Cost | |
| Wei-Gang | Lightning performance of 500-kV double-circuit line schemes for the three-gorge project | |
| Xie et al. | Lightning Overvoltage Simulation Research of Typical 35kV Overhead Lines | |
| Sestasombut et al. | The Analysis of Lightning Strikes to MEA’s Distribution Lines on Different Impact Positions | |
| CN205688919U (en) | DC line and ground connection polar curve are with tower power transmission tower arranged vertically | |
| Sones et al. | Overview on transient overvoltages and insulation design for a high voltage transmission system | |
| CN107546639B (en) | A kind of distribution transmission line of electricity remodeling method and device | |
| Orawski et al. | Overhead distribution lines—some reflections on design | |
| Wenhua et al. | Application of coupling ground wire in distribution line lightning protection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |