CN114744576B - Method and system for optimizing design of alternating-current transmission line to direct-current operation - Google Patents
Method and system for optimizing design of alternating-current transmission line to direct-current operation Download PDFInfo
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- CN114744576B CN114744576B CN202210232235.8A CN202210232235A CN114744576B CN 114744576 B CN114744576 B CN 114744576B CN 202210232235 A CN202210232235 A CN 202210232235A CN 114744576 B CN114744576 B CN 114744576B
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Classifications
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- 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
- H02G7/20—Spatial arrangements or dispositions of lines or cables on poles, posts or towers
- H02G7/205—Installation of electric cables, extending along a pole
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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Abstract
The invention discloses a method and a system for optimizing the operation of an alternating current transmission line, which adopt a direct current insulator to replace a suspension string, a jumper string and a tension string of the alternating current transmission line, acquire a tower head gap of a straight line tower and a jumper gap of the tension tower through the configuration of the direct current insulator string and the air gaps of the direct current transmission line under different operation working conditions, adapt the tower head gap of the straight line tower and the jumper gap of the tension tower by adjusting the maximum voltage of the direct current transmission line, and ensure that the tripping rate of the direct current transmission line meets the operation requirement, and acquire the maximum voltage of the optimized direct current transmission line, the configuration of the direct current insulator string and the air gaps of the direct current transmission line under different operation working conditions, so that the direct current transmission line after alternating current straightening has the highest voltage level and transmission capacity as much as possible, and simultaneously satisfies the safe and stable operation of the flexible direct current transmission line, thereby realizing the reliable transmission of electric energy.
Description
Technical Field
The invention relates to a method and a system for optimizing and designing alternating current transmission line to direct current operation, and belongs to the technical field of direct current transmission.
Background
Compared with the traditional alternating current transmission mode, the novel power grid constructed by flexible direct current transmission has the advantages of rapid operation characteristic control and capability of improving and dividing the power network, has stronger technical advantages in the aspects of capacity increase, island power supply, alternating current system interconnection, large-scale new energy grid connection and the like of the urban power grid, and has wide application prospect in the aspect of changing the development pattern of the power grid.
In coastal economically developed areas, the contradiction between power supply and demand is increasingly prominent, and in consideration of the fact that new power transmission corridors in certain areas are difficult to obtain, the cost of a newly built power transmission line is very high, and the land-characteristic cost of the power transmission corridors far exceeds the manufacturing cost of a power transmission line body. In order to fully utilize the existing path channel resources and solve the problem of extremely difficult transmission line corridor, an alternating current line is necessary to be changed into a direct current, but no corresponding method exists at present.
Disclosure of Invention
The invention provides a method and a system for optimizing and designing alternating current transmission line to direct current operation, which solve the problems disclosed in the background technology.
In order to solve the technical problems, the invention adopts the following technical scheme:
The method for optimizing the design of alternating current transmission line to direct current operation comprises the following steps:
According to the operation voltage of the alternating current circuit, primarily determining the maximum voltage of the direct current circuit;
Replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
Calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
Checking the tower head gap of the straight line tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
In response to the problems that the gap of the tower head of the linear tower is insufficient or over-large in electrical gap, the gap of the jumper of the tension tower is insufficient or over-large in electrical gap, or the tripping rate of the direct current line is not met with the operation requirement according to the protection angle of the tower, the configuration of the direct current insulator string and the checking of the air gap of the direct current line under different operation working conditions, the maximum voltage of the direct current line is adjusted, the configuration of the direct current insulator string and the air gap of the direct current line under different operation working conditions are recalculated until the gap of the tower head of the linear tower is free from the problems that the gap of the linear tower is insufficient or over-large in electrical gap, the gap of the jumper of the tension tower is free from the problems that the gap of the tension tower is insufficient or over-large in electrical gap, and the tripping rate of the direct current line meets the operation requirement, and the preferred maximum voltage of the direct current line, the configuration of the direct current insulator string and the air gap of the direct current line under different operation working conditions are obtained.
The formula for preliminarily determining the maximum voltage of the direct current line is as follows:
Where U dc is the maximum voltage level of the dc line and U ac is the operating voltage of the ac line.
Replacing alternating current insulators in the tangent tower wire suspension string, the strain tower wire jumper string and the strain tower wire strain string with direct current insulator strings, and calculating the configuration of the direct current insulator strings according to the preliminarily determined direct current line maximum voltage, wherein the configuration comprises the following steps:
Alternating current insulators in the tangent tower wire suspension string, the strain tower wire jumper string and the strain tower wire strain string are replaced by direct current insulators, and the configuration of the direct current insulator string is calculated by adopting a creepage ratio distance method or a pollution withstand voltage method according to the preliminarily determined direct current line maximum voltage.
The direct current insulator comprises a direct current composite insulator and a direct current disc type insulator, wherein alternating current insulators in the suspension string of the straight line tower wire and the jumper string of the tension tower wire are replaced by the direct current composite insulator, and alternating current insulators in the tension wire and the tension wire of the tension tower are replaced by the direct current disc type insulator.
The configuration of the direct current insulator string calculated by adopting the creepage ratio distance method is as follows:
DC composite insulator: when the creepage distance per unit length is L c, the dry arc distance is taken Wherein λ= 1.0669 ·ln (ESDD) +7.5127 is the creepage distance of the direct current line, ESDD is equivalent salt density, and U is the direct current nominal voltage;
DC disc insulator: when the effective creepage distance of a single piece is L s, the number of the DC disc type insulators is taken
The configuration of the direct current insulator string calculated by adopting the pollution withstand voltage method is as follows:
DC composite insulator: when the pollution flashover voltage u' 50％ is per unit length, the dry arc distance is taken Wherein U m is the maximum voltage of the direct current line, K 1 is the gray density correction coefficient, K 2 is the non-uniform correction coefficient, n is the standard deviation multiple, and sigma is the standard deviation of the pollution flashover voltage of the direct current insulator;
DC disc insulator: when the single-chip pollution flashover voltage is u 50％, the number of the direct current disc type insulators is taken
Adjusting a maximum voltage of a direct current line, comprising:
if the clearance of the tower head of the linear tower has the problem of insufficient electric clearance, the clearance of the jumper wire of the tension tower has the problem of insufficient electric clearance, or the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length;
If the gap of the tower head of the linear tower has the problem of overlarge electric gap margin or the problem of overlarge electric gap margin of the jumper wire gap of the tension tower, the maximum voltage of the direct current circuit is increased according to a preset step length.
An optimization design system for changing an alternating current transmission line into a direct current operation, comprising:
A preliminary maximum voltage determination module: according to the operation voltage of the alternating current circuit, primarily determining the maximum voltage of the direct current circuit;
and (3) configuring a calculation module: replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
an air gap calculation module: calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
tower head clearance and jumper wire clearance calculation module: checking the tower head gap of the straight line tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
And a determination module: and in response to the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resistant tower, or the operation requirement is not met according to the protection angle of the tower, the configuration of the direct-current insulator string and the tripping rate of the direct-current line for checking the air gap of the direct-current line under different operation working conditions, the maximum voltage of the direct-current line is adjusted, the configuration calculation module and the air gap calculation module are transferred to calculate the air gap of the configuration of the direct-current insulator string and the direct-current line under different operation working conditions again until the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resistant tower, and the tripping rate of the direct-current line meets the operation requirement, and the optimal maximum voltage of the direct-current line, the configuration of the direct-current insulator string and the air gap of the direct-current line under different operation working conditions are obtained.
The determining module comprises a voltage adjusting module for adjusting the maximum voltage of the direct current line;
The voltage regulation module includes:
A first adjusting module: if the clearance of the tower head of the linear tower has the problem of insufficient electric clearance, the clearance of the jumper wire of the tension tower has the problem of insufficient electric clearance, or the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length;
and a second adjusting module: if the gap of the tower head of the linear tower has the problem of overlarge electrical gap margin or the electrical gap margin of the jumper wire gap of the tension tower is overlarge, the maximum voltage of the direct current circuit is increased according to a preset step length.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform an ac transmission line to dc operation optimization design method.
A computing device comprising one or more processors, one or more memories, and one or more programs, wherein one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the ac transmission line to dc operation optimization design methods.
The invention has the beneficial effects that: according to the invention, the hanging string, the jumper string and the tension string of the alternating current circuit are replaced by adopting the direct current insulator, the gap between the tower head of the linear tower and the gap between the jumper wire of the tension tower are obtained through the configuration of the direct current insulator string and the air gap of the direct current circuit under different working conditions, the maximum voltage of the direct current circuit is adjusted, the gap between the tower head of the linear tower and the gap between the jumper wire of the tension tower are adapted, the tripping rate of the direct current circuit meets the operation requirement, and the optimal maximum voltage of the direct current circuit, the configuration of the direct current insulator string and the air gap of the direct current circuit under different working conditions are obtained, so that the direct current circuit after alternating current is straightened has the highest voltage grade and the conveying capacity as much as possible, the safe and stable operation of the flexible direct current circuit is satisfied, and the reliable transmission of electric energy is realized.
Drawings
FIG. 1 is a tower for AC transmission line to DC operation;
Fig. 2 is a flow chart of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
As shown in FIG. 1, the tower for changing the current AC transmission line to DC operation comprises a tangent tower, a strain tower, wires, a wire suspension string, an electric gap, a jumper wire, a wire jumper wire string and a wire strain string. In order to fully utilize the existing power transmission equipment, the alternating current power transmission line is changed into a direct current power transmission line on the premise of not modifying the existing tangent tower and strain tower of the alternating current line and not replacing wires.
The method specifically adopted can be as shown in fig. 2, and the method for optimizing the design of the alternating current transmission line to the direct current operation comprises the following steps:
Step 1, preliminarily determining the maximum voltage of a direct current circuit according to the operation voltage of the alternating current circuit;
Step 2, replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
step 3, calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
Step 4, checking the tower head gap of the straight tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
Step 5, in response to the problems of insufficient electrical clearance or overlarge margin of the tower head clearance of the linear tower, insufficient electrical clearance of the jumper clearance of the tension tower, or failure of the operation requirement according to the protection angle of the tower, the configuration of the DC insulator string and the tripping rate of the DC line for checking the air clearance of the DC line under different operation working conditions, adjusting the maximum voltage of the DC line, and turning to step 2; if the gap of the tower head of the linear tower does not have the problem of insufficient electric gap or overlarge margin, the gap of the tension tower jumper does not have the problem of insufficient electric gap or overlarge margin, and the tripping rate of the direct current circuit meets the operation requirement, the optimal maximum voltage of the direct current circuit, the configuration of the direct current insulator string and the air gap of the direct current circuit under different operation working conditions are obtained.
According to the method, the hanging string, the jumper string and the tension string of the alternating current circuit are replaced by adopting the direct current insulator, the gap between the tower head of the linear tower and the gap between the jumper of the tension tower are obtained through the configuration of the direct current insulator string and the air gap of the direct current circuit under different working conditions, the maximum voltage of the direct current circuit is adjusted, the gap between the tower head of the linear tower and the gap between the jumper of the tension tower are adapted, the tripping rate of the direct current circuit meets the operation requirement, the optimal maximum voltage of the direct current circuit, the configuration of the direct current insulator string and the air gap of the direct current circuit under different working conditions are obtained, the direct current circuit after alternating current straightening has the highest voltage grade and the conveying capacity as much as possible, the safe and stable operation of the flexible direct current circuit is met, and the reliable transmission of electric energy is realized.
Before the method is carried out in real time, the aim of transformation needs to be known, namely, the wire model of the original alternating current line, the tower head sizes of the tangent tower and the tension tower, the structure height of the insulator and the air gap of the tower head need to be obtained.
According to the operation voltage of the alternating current line, the maximum voltage of the direct current line is preliminarily determined, and the specific calculation formula can be as follows:
Where U dc is the maximum voltage level of the dc line and U ac is the operating voltage of the ac line.
Unlike ac transmission lines, high voltage dc lines are more susceptible to electrochemical corrosion in a humid environment than ac voltages. Electrochemical corrosion of the insulator affects the electrical insulation strength and mechanical resistance of the insulator string, resulting in a reduction in the fouling withstand voltage and mechanical failure load. The original alternating current insulator is difficult to meet the long-term safe and stable operation of a direct current circuit, so that the alternating current insulators in the straight line tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string are required to be replaced by the direct current insulators.
The direct current insulator generally comprises a direct current composite insulator and a direct current disc insulator, and in order to improve the direct current operation voltage of an alternating current circuit as much as possible, the composite insulator is utilized to have excellent pollution flashover resistance, the alternating current insulators in the suspension string of the straight line tower wire and the jumper string of the tension tower wire are replaced by the direct current composite insulator, the alternating current insulators in the tension string of the tension tower wire are replaced by the direct current disc insulator, and then the configuration of the direct current insulator string is calculated by adopting a creepage ratio distance method or a pollution withstand voltage method.
Calculating the configuration of the direct current insulator string by adopting a creepage ratio distance method according to the preliminarily determined maximum voltage of the direct current line:
defining a direct current nominal voltage as U, an equivalent salt density as ESDD, and a direct current line creepage distance as lambda= 1.0669.ln (ESDD) +7.5127;
DC composite insulator: when the creepage distance per unit length is L c, the dry arc distance is taken
DC disc insulator: when the effective creepage distance of a single piece is L s, the number of the DC disc type insulators is taken
Calculating the configuration of the direct current insulator string by adopting a pollution withstand voltage method:
defining a direct current line maximum voltage U m, wherein the gray density correction coefficient is K 1, the non-uniformity correction coefficient is K 2, the standard deviation multiple is n, and the standard deviation sigma of the direct current insulator pollution flashover voltage is defined;
DC composite insulator: when the pollution flashover voltage u' 50％ is per unit length, the dry arc distance is taken
DC disc insulator: when the single-chip pollution flashover voltage is u 50％, the number of the direct current disc type insulators is taken
According to the direct current discharge characteristics of the air gap of the wire pair tower, the air gap of the direct current circuit under different working conditions can be calculated, wherein the air gap of the direct current circuit under working voltage, operation, lightning and live working conditions can be:
Obtaining 50% discharge voltage of the wire to the air gap of the pole tower according to the direct current rated voltage U N, the air density coefficient k 1, the humidity correction coefficient k 2, the safety coefficient k 3 and the relative standard deviation sigma s of the direct current discharge voltage of the air gap Calculating an air gap of the working voltage according to the direct current discharge characteristic of the air gap;
Obtaining a 50% operating condition discharge voltage of the positive electrode of the air gap of the wire pair tower according to the highest operating voltage U m, the air density coefficient k 1, the humidity correction coefficient k 2, the operating excessive pressure multiple k 4 and the variation coefficient sigma' s of the air gap under the operating excessive pressure Then calculating an over-atmospheric air gap according to the positive polarity operation impulse discharge voltage discharge characteristic of the guide wire to the tower air gap;
Under the working condition of excessive lightning pressure, the air gap positive polarity lightning impulse 50% discharge voltage U '50％ is matched with 80% of the 50% lightning impulse discharge voltage U 50％ of the insulator string (the gap is matched according to the insulation length required by 0-level pollution), and U' 50％＝80％·U50％;
in the live working clearance, the standard deviation multiple is changed from 2 to 3 by the operation excessive pressure in consideration of the safety of live working personnel, namely the withstand voltage guarantee rate is 99.86%.
Under the condition that the configuration of the direct current insulator string and the air gaps of the direct current line under different working conditions are calculated, the tower head gap of the straight line tower and the jumper gap of the tension tower are obtained.
Judging whether the gap between the tower head of the linear tower and the gap between the tension tower jumper are insufficient or oversized, if the gap between the tower head of the linear tower is insufficient or the gap between the tension tower jumper is insufficient, reducing the maximum voltage of the direct current line according to a preset step length (generally 5kV or 10 kV), turning to the step 2, if the gap between the tower head of the linear tower is oversized or the gap between the tension tower jumper is oversized, increasing the maximum voltage of the direct current line according to the preset step length (generally 5kV or 10 kV), turning to the step 2, otherwise, indicating gap adaptation.
Under the condition of gap adaptation, checking the tripping rate of the direct current line according to the protection angle of the tower, the configuration of the direct current insulator string and the air gaps of the direct current line under different operation working conditions, if the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length (generally 5kV or 10 kV), turning to the step 2, and if the tripping rate of the direct current line does not meet the operation requirement, then the current maximum voltage of the direct current line, the configuration of the direct current insulator string and the air gaps of the direct current line under different operation working conditions are the preferable results, and completing the design of alternating current-direct current key technical parameters.
Based on the method, the existing tower head electric gap of the existing tangent tower and the existing tower head electric gap of the existing tension tower are facilitated, the voltage class of the direct current line, the external insulation configuration and the electric gap design are carried out, the wire hanging string, the wire tension string and the wire jumper string are replaced, and the jumper is manufactured again, so that the line after direct current transformation simultaneously meets the electric gap requirements of working voltage, excessive operation voltage and excessive lightning voltage.
Based on the same technical scheme, the invention also discloses a software system of the method, and an alternating current transmission line changes a direct current operation optimization design system, which comprises the following steps:
a preliminary maximum voltage determination module: the maximum voltage of the DC line is initially determined based on the operating voltage of the AC line.
And (3) configuring a calculation module: replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
an air gap calculation module: calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
tower head clearance and jumper wire clearance calculation module: checking the tower head gap of the straight line tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
And a determination module: and responding to the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resisting tower, or according to the protection angle of the tower, the configuration of the direct-current insulator string and the fact that the tripping rate of the direct-current line is not met with the operation requirement in the air gap check of the direct-current line under different operation working conditions, regulating the maximum voltage of the direct-current line, transferring to a configuration calculation module and an air gap calculation module, and recalculating the air gap of the configuration of the direct-current insulator string and the direct-current line under different operation working conditions until the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resisting tower, and the tripping rate of the direct-current line meets the operation requirement, and the optimal maximum voltage of the direct-current line, the configuration of the direct-current insulator string and the air gap of the direct-current line under different operation working conditions are obtained.
The determining module comprises a voltage adjusting module for adjusting the maximum voltage of the direct current line;
The voltage regulation module includes:
A first adjusting module: if the clearance of the tower head of the linear tower has the problem of insufficient electric clearance, the clearance of the jumper wire of the tension tower has the problem of insufficient electric clearance, or the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length;
and a second adjusting module: if the gap of the tower head of the linear tower has the problem of overlarge electrical gap margin or the electrical gap margin of the jumper wire gap of the tension tower is overlarge, the maximum voltage of the direct current circuit is increased according to a preset step length.
The above-mentioned flow transmission line changes the consistency of the data processing flow and method of each module in the direct current system, and the description is not repeated here.
Based on the same technical scheme, the invention also discloses a computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to execute the alternating current transmission line to change direct current operation optimization design method.
Based on the same technical scheme, the invention also discloses a computing device, which comprises one or more processors, one or more memories and one or more programs, wherein the one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs comprise instructions for executing the alternating current transmission line direct current operation optimizing design method.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof, but rather as providing for the use of additional embodiments and advantages of all such modifications, equivalents, improvements and similar to the present invention are intended to be included within the scope of the present invention as defined by the appended claims.
Claims (10)
1. The method for optimizing the design of alternating current transmission line to direct current operation is characterized by comprising the following steps:
According to the operation voltage of the alternating current circuit, primarily determining the maximum voltage of the direct current circuit;
Replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
Calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
Checking the tower head gap of the straight line tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
In response to the problems that the gap of the tower head of the linear tower is insufficient or over-large in electrical gap, the gap of the jumper of the tension tower is insufficient or over-large in electrical gap, or the tripping rate of the direct current line is not met with the operation requirement according to the protection angle of the tower, the configuration of the direct current insulator string and the checking of the air gap of the direct current line under different operation working conditions, the maximum voltage of the direct current line is adjusted, the configuration of the direct current insulator string and the air gap of the direct current line under different operation working conditions are recalculated until the gap of the tower head of the linear tower is free from the problems that the gap of the linear tower is insufficient or over-large in electrical gap, the gap of the jumper of the tension tower is free from the problems that the gap of the tension tower is insufficient or over-large in electrical gap, and the tripping rate of the direct current line meets the operation requirement, and the preferred maximum voltage of the direct current line, the configuration of the direct current insulator string and the air gap of the direct current line under different operation working conditions are obtained.
2. The method for optimizing design of alternating current transmission line to direct current operation according to claim 1, wherein the formula for preliminarily determining the maximum voltage of the direct current line is:
Where U dc is the maximum voltage level of the dc line and U ac is the operating voltage of the ac line.
3. The method for optimizing design of alternating current transmission line to direct current operation according to claim 1, wherein alternating current insulators in the tangent tower wire overhang string, the strain tower wire jumper string and the strain tower wire strain string are replaced with direct current insulator strings, and the configuration of the direct current insulator strings is calculated according to the preliminarily determined direct current line maximum voltage, comprising:
Alternating current insulators in the tangent tower wire suspension string, the strain tower wire jumper string and the strain tower wire strain string are replaced by direct current insulators, and the configuration of the direct current insulator string is calculated by adopting a creepage ratio distance method or a pollution withstand voltage method according to the preliminarily determined direct current line maximum voltage.
4. The optimal design method for changing alternating current transmission lines to direct current operation according to claim 3, wherein the direct current insulators comprise direct current composite insulators and direct current disc insulators, alternating current insulators in a tangent tower wire suspension string and a strain tower wire jumper string are replaced by the direct current composite insulators, and alternating current insulators in the strain tower wire strain string are replaced by the direct current disc insulators.
5. The optimal design method for changing an alternating current transmission line to direct current operation according to claim 4, wherein the configuration of the direct current insulator string calculated by adopting a creepage ratio distance method is as follows:
DC composite insulator: when the creepage distance per unit length is L c, the dry arc distance is taken Wherein λ= 1.0669 ·ln (ESDD) +7.5127 is the creepage distance of the direct current line, ESDD is equivalent salt density, and U is the direct current nominal voltage;
DC disc insulator: when the effective creepage distance of a single piece is L s, the number of the DC disc type insulators is taken
The configuration of the direct current insulator string calculated by adopting the pollution withstand voltage method is as follows:
DC composite insulator: when the pollution flashover voltage u' 50％ is per unit length, the dry arc distance is taken Wherein U m is the maximum voltage of the direct current line, K 1 is the gray density correction coefficient, K 2 is the non-uniform correction coefficient, n is the standard deviation multiple, and sigma is the standard deviation of the pollution flashover voltage of the direct current insulator;
DC disc insulator: when the single-chip pollution flashover voltage is u 50％, the number of the direct current disc type insulators is taken
6. The method for optimizing the design of an ac transmission line to dc operation according to claim 1, wherein adjusting the maximum voltage of the dc line comprises:
if the clearance of the tower head of the linear tower has the problem of insufficient electric clearance, the clearance of the jumper wire of the tension tower has the problem of insufficient electric clearance, or the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length;
If the gap of the tower head of the linear tower has the problem of overlarge electrical gap margin or the electrical gap margin of the jumper wire gap of the tension tower is overlarge, the maximum voltage of the direct current circuit is increased according to a preset step length.
7. The alternating current transmission line changes direct current operation optimal design system, which is characterized by comprising:
A preliminary maximum voltage determination module: according to the operation voltage of the alternating current circuit, primarily determining the maximum voltage of the direct current circuit;
and (3) configuring a calculation module: replacing alternating current insulators in the tangent tower wire suspension string, the tension tower wire jumper string and the tension tower wire tension string with direct current insulators, and calculating the configuration of the direct current insulators according to the preliminarily determined direct current line maximum voltage;
an air gap calculation module: calculating the air gaps of the direct current circuit under different working conditions according to the preliminarily determined maximum voltage of the direct current circuit by utilizing the direct current discharge characteristics of the air gaps of the wire pair tower;
tower head clearance and jumper wire clearance calculation module: checking the tower head gap of the straight line tower and the jumper wire gap of the tension tower according to the configuration of the direct current insulator string and the air gaps of the direct current circuit under different operation working conditions;
And a determination module: and in response to the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resistant tower, or the operation requirement is not met according to the protection angle of the tower, the configuration of the direct-current insulator string and the tripping rate of the direct-current line for checking the air gap of the direct-current line under different operation working conditions, the maximum voltage of the direct-current line is adjusted, the configuration calculation module and the air gap calculation module are transferred to calculate the air gap of the configuration of the direct-current insulator string and the direct-current line under different operation working conditions again until the problems that the electric gap is insufficient or the margin is too large in the tower head gap of the straight-line tower, the electric gap is insufficient or the margin is too large in the jumper gap of the tension-resistant tower, and the tripping rate of the direct-current line meets the operation requirement, and the optimal maximum voltage of the direct-current line, the configuration of the direct-current insulator string and the air gap of the direct-current line under different operation working conditions are obtained.
8. The system of claim 7, wherein the determining module comprises a voltage adjustment module for adjusting a maximum voltage of the dc link;
The voltage regulation module includes:
A first adjusting module: if the clearance of the tower head of the linear tower has the problem of insufficient electric clearance, the clearance of the jumper wire of the tension tower has the problem of insufficient electric clearance, or the tripping rate of the direct current line does not meet the operation requirement, reducing the maximum voltage of the direct current line according to a preset step length;
and a second adjusting module: if the gap of the tower head of the linear tower has the problem of overlarge electrical gap margin or the electrical gap margin of the jumper wire gap of the tension tower is overlarge, the maximum voltage of the direct current circuit is increased according to a preset step length.
9. A computer readable storage medium storing one or more programs, wherein the one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-6.
10. A computing device, comprising:
One or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods of claims 1-6.
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