CN115882412A - Ice melting method for ground wire of wire without power failure - Google Patents
Ice melting method for ground wire of wire without power failure Download PDFInfo
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- CN115882412A CN115882412A CN202211653786.8A CN202211653786A CN115882412A CN 115882412 A CN115882412 A CN 115882412A CN 202211653786 A CN202211653786 A CN 202211653786A CN 115882412 A CN115882412 A CN 115882412A
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Abstract
The invention provides a method for melting ice on a ground wire of a wire without power failure, which comprises the following steps: determining the range and the length of the ground wire ice melting; determining the ice melting time, and obtaining the maximum value and the minimum value of the ice melting current of the ground wire; obtaining the maximum length of single ice melting according to the ice melting current value limit value, and dividing the ice melting range into a single ice melting section or a plurality of ice melting sections; selecting a ground wire ice-melting wiring mode of the section according to the length of the ice-melting section and the position of an access point of an ice-melting power supply; calculating the ice melting capacity range and the ice melting voltage range required by each section according to the ground wire ice melting wiring mode, and determining the rated current, the rated voltage and the rated capacity of an ice melting power supply; selecting an access mode of the ice melting power supply; insulators are additionally arranged on the ground wire suspension string and the strain insulator string, and an insulating drainage wire clamp is additionally arranged on the drainage wire; installing an arcing horn on the ground wire ice melting string insulator; and accessing a ground wire induction voltage suppression device to perform ground wire ice melting operation.
Description
Technical Field
The invention relates to the technical field of ground wire ice melting, in particular to a method for melting ice on a ground wire without power failure of a lead.
Background
Ice and snow cover, as a special meteorological condition, has had a serious impact on the safe operation of many overhead transmission lines around the world. China is influenced by climatic conditions, micro-terrain and micro-meteorological conditions, and ice disasters frequently occur. Icing of the ground wire of the power transmission line is serious, tower falling and line breaking accidents are caused, and great damage is brought to a power grid.
Because the ground wire does not carry the circulating current in the ice and snow weather, the wire is easier to be coated with ice compared with the wire. The damage condition of ice disaster accidents in recent years is analyzed, and the ice coating often causes damage or slippage of an overhead ground wire and damage of a ground wire bracket at first, so that the trip and shutdown of a line are caused, and further, accidents such as damage of an iron tower and the like are caused. Through statistics, the proportion of ground wire faults in the line icing faults is far higher than that of lead faults, and the overhead ground wire is the weakest link in the power transmission line. Therefore, the ice melting of the overhead ground wire is realized, and the ice melting device has very important significance for improving the integral ice-proof capacity of the power transmission line and ensuring the power supply reliability of a power grid.
The ice melting mode of the ground wire is usually the ice melting by electric heating after the ground wire is electrified, the used ice melting power supply is generally positioned in substations at two ends of the line, and the existing ice melting scheme of the ground wire needs to form an ice melting loop by connecting a lead in series with the ground wire so as to lap the ice melting device in the station. Therefore, when the ground wire melts ice, the conductor needs to be shut down at the same time, so that the normal power supply of the line is influenced, and the power transmission function of the line is lost during the ice melting period.
Disclosure of Invention
The invention aims to at least solve one of the technical problems that the normal power supply of a line is influenced by stopping the operation of a conductor when the ice melting of a ground wire is carried out, and the power transmission function of the line is lost during the ice melting period in the prior art.
Therefore, the invention provides a method for melting ice on a ground wire without power failure of a lead.
The invention provides a method for melting ice on a ground wire of a wire without power failure, which comprises the following steps:
s1, determining a section needing ground wire de-icing according to the partition condition of an engineering ice area, the ground wire model selection condition and the micro-meteorological area of the engineering micro-terrain, and determining the range and the length of the ground wire de-icing;
s2, determining ice melting duration according to the relation between the environmental temperature, the wind speed, the ice coating thickness and the ice melting current, and obtaining the maximum value and the minimum value of the ice melting current of the ground wire;
s3, obtaining the maximum length Lmax of single ice melting according to the ice melting current value limit value, and dividing an ice melting range into a single ice melting section or a plurality of ice melting sections according to the Lmax;
s4, selecting a ground wire ice melting wiring mode of the ice melting section according to the length of the ice melting section and the position of an ice melting power supply access point, wherein the ground wire ice melting wiring mode comprises a series ice melting wiring mode and a parallel ice melting wiring mode;
s5, calculating the ice melting capacity range and the ice melting voltage range required by each section according to the ice melting wiring mode of the ground wire selected by the ice melting section, and determining the rated current, the rated voltage and the rated capacity of the ice melting power supply;
s6, insulators are additionally arranged on the ground wire suspension string and the strain insulator string, and an insulating drainage wire clamp is additionally arranged on the drainage wire, so that the insulation transformation of the ground wire is realized;
s7, additionally arranging arc attracting corners on insulators of the ice melting suspension string and the strain insulator string of the ground wire;
and S8, performing ground wire ice melting operation.
The method for melting ice on the ground wire without power failure of the lead wire according to the technical scheme of the invention can also have the following additional technical characteristics:
in the technical scheme, when the length of the ice melting section is not more than the maximum length Lmax of single ice melting, the ice melting section adopts a series ice melting connection mode, and the series ice melting connection mode comprises a first series ice melting connection mode and a second series ice melting connection mode;
when the ice melting section adopts a first series ice melting wiring mode, two ground wires are respectively connected to the anode and the cathode of an ice melting power supply at the starting end of the ice melting section, and the two ground wires are connected in a lap joint manner through the series wire at the tail end of the ice melting section to form a series loop;
when the ice melting section adopts a second series ice melting connection mode, one of the two ground wires is connected to the anode and the cathode of the ice melting power supply at any point in the ice melting section, the ground wires on two sides of the ground wire connected to the ice melting power supply are subjected to separation treatment, and the two ground wires are respectively connected in a lap joint manner through the series wires at the starting end and the tail end of the ice melting section to form a series loop.
In the technical scheme, when the ice melting section adopts a series ice melting connection mode, the total resistance of the ice melting section is the sum of the resistance values of two ground wires in the ice melting section.
In the technical scheme, when the length of the ice melting section is greater than the maximum length Lmax of single ice melting, the ice melting section adopts a parallel ice melting connection mode, the middle points of the resistors of the two ground wires in the ice melting section are respectively connected to the anode and the cathode of an ice melting power supply, and the two ground wires are respectively connected in a lap joint manner through a series line at the starting end and the tail end of the ice melting section to form a parallel loop.
In the technical scheme, when the ice melting section adopts a parallel ice melting connection mode, the total resistance of the ice melting section is half of the sum of the resistance values of two ground wires in the ice melting section.
In the technical scheme, when the ice melting section adopts a parallel ice melting connection mode, the ice melting section can be subjected to unilateral ice melting according to the severe ice coating condition, namely two ground wires are connected in a lap joint mode through a serial line at the starting end of the ice melting section, and the two ground wires at the tail end of the ice melting section are not connected, or the two ground wires are connected in a lap joint mode through the serial line at the tail end of the ice melting section, and the two ground wires at the starting end of the ice melting section are not connected.
In the above technical solution, in S5, when the ice melting section adopts a series ice melting connection manner, the ice melting voltage range of the section is IminR to ImaxR, and the ice melting capacity range is Imin 2 R～Imax 2 R, the rated current required by the ice melting power supply is Imax, the rated voltage is ImaxR, and the rated capacity is Imax 2 R；
When the ice melting section adopts a parallel ice melting connection mode, the ice melting voltage range of the section is IminR-ImaxR, and the ice melting capacity range is 2Imin 2 R～2Imax 2 R, the rated current required by the ice melting power supply is 2Imax, the rated voltage is ImaxR,rated capacity of 2Imax 2 R；
And Imin is the minimum value of the ground wire ice melting current obtained in S2, imax is the maximum value of the ground wire ice melting current obtained in S2, and R is the total resistance of the ice melting section.
In the above technical solution, the method further comprises:
and selecting the ice melting power supply according to the actual condition of the line site and the rated current, the rated voltage and the rated capacity required by the ice melting power supply obtained in the step S5, wherein the ice melting power supply comprises a movable ice melting vehicle, an offline fixed ice melting device, an ice melting power supply in a transformer substation near the lap joint of a newly-built connecting line and the like.
In the above technical solution, the method further comprises: an induced voltage suppression device is additionally arranged on the ground wire.
In the above technical solution, in S6, after the ground wire is transformed into an insulated state, at least one point of the ground wire in the ice melting section is grounded when ice is not melted, and the ground point is disconnected during ice melting to form an insulated loop.
In summary, due to the adoption of the technical characteristics, the invention has the beneficial effects that:
the novel ground wire ice melting method is simple in structure and scientific and reasonable in design, the ground wire forms an ice melting loop independently, and the ice melting of the ground wire can be realized without the participation of a lead, namely the lead is not powered off.
After the novel ice melting technology of 'melting ice on the ground wires without power outage' is adopted, on the premise that the safety and reliability of the power transmission line are not reduced, two ground wires can form a complete loop to melt ice according to the length and the section distribution of the ground wires, the problem that the wires need to be stopped in the existing ground wire ice melting technology is effectively solved, the wires keep the power transmission function while the ground wires melt ice, and the power outage loss of the power transmission line is reduced.
The wiring method for de-icing the ground wire without power failure of the lead reduces a large number of lapping operations of the lead wire and the ground wire before de-icing and after de-icing, and saves de-icing time.
According to the invention, series connection once ice melting or parallel connection once ice melting can be selected according to the length of the ice melting section and the ice melting power supply access point, so that the ice melting of the ground wires with different lengths can be efficiently and reliably completed.
In the parallel ice-melting wiring mode, the ground wires at two sides of the access point can be melted for one time after being connected in parallel, and the single-side ground wire section can be selected for independent ice melting according to the real-time severe ice-coating condition.
The ice melting power supply can be selected in a mode of selecting a movable ice melting vehicle, a fixed ice melting device under a newly-added line, or an ice melting power supply device in a transformer substation near the lap joint of a newly-built ice melting connecting line and the like according to comprehensive consideration of the current, the voltage, the capacity, the actual situation of the site and the like required by ice melting.
The influence of ground wire induction current on uninterrupted ice melting is considered, the ground wire induction voltage under different running states of the wire needs to be researched, and the ground wire induction voltage suppression device is additionally arranged, so that the reliability of self starting of the ice melting power is guaranteed.
The invention takes the ground wire insulation transformation method into consideration, and ensures the insulation connection of the ground wire of the ice melting section and the iron tower.
In the invention, the arcing horn (discharge gap) is additionally arranged on the insulator of the ground wire ice melting string, and the single-point or multi-point grounding of the ground wire of the ice melting section is considered when ice is not melted, so that the influence on the line lightning protection performance after the insulation transformation of the ground wire of the ice melting section is reduced.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a flowchart of a method for melting ice on a ground wire without power failure according to an embodiment of the present invention.
FIG. 2 is a schematic wiring diagram of a first serial ice-melting wiring manner in a method for melting ice on a ground wire without power failure of a wire according to an embodiment of the present invention;
FIG. 3 is a schematic wiring diagram of a second serial connection ice-melting connection mode in a method for melting ice on a ground wire without power failure of a lead according to an embodiment of the present invention;
FIG. 4 is a schematic wiring diagram of a parallel connection ice-melting wiring manner in a method for melting ice on a ground wire without power failure of a wire according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of the ground wire de-icing insulation string and arcing horn (discharge gap) added in a method for de-electrifying the ground wire and de-icing the ground wire according to one embodiment of the invention;
FIG. 6 is a schematic diagram of grounding under an insulation lead for wire deicing in a method for wire deicing without power outage according to an embodiment of the present invention;
FIG. 7 is a schematic diagram illustrating the connection of a ground line induced voltage suppression device in a method for melting ice on a ground line without power outage according to an embodiment of the present invention;
FIG. 8 is a schematic diagram illustrating division of ice melting sections in a method for melting ice on a ground wire without power failure according to an embodiment of the present invention;
wherein, the correspondence between the reference numbers and the component names in fig. 1 to 8 is:
1. a positive temporary lap joint line; 2. a negative electrode temporary lap wire; 3. and connecting the wires in series.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention, taken in conjunction with the accompanying drawings and detailed description, is set forth below. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced otherwise than as specifically described herein and, therefore, the scope of the present invention is not limited by the specific embodiments disclosed below.
A method for melting ice on a ground wire without power failure according to some embodiments of the present invention is described below with reference to fig. 1 to 8.
Some embodiments of the present application provide a method for de-icing a ground wire without power outage of the wire.
As shown in fig. 1 to 8, a first embodiment of the present invention provides a method for melting ice on a ground wire without power outage, which includes the following steps:
s1, determining a section needing ground wire de-icing according to the partition condition of an engineering ice area, the ground wire model selection condition, the micro-meteorological area of the engineering micro-terrain and the like, and determining the range and the length of the ground wire de-icing;
s2, determining ice melting duration according to the relation between the environment temperature, the wind speed, the ice coating thickness and the typical ground wire ice melting current, and obtaining a maximum value Imax and a minimum value Imin of the ground wire ice melting current;
s3, obtaining the maximum length Lmax of single ice melting according to the ice melting current value limit value, determining the maximum length of an ice melting section according to the Lmax, dividing the ice melting range into a single or a plurality of ice melting sections, wherein the length of each section is L1, L2 and L3, 823082823082sign, \8230signand Ln;
s4, selecting a ground wire ice melting wiring mode of the ice melting section according to the length of the ice melting section and the position of an ice melting power supply access point, wherein the ground wire ice melting wiring mode comprises a series ice melting wiring mode and a parallel ice melting wiring mode;
when the length of the ice melting section is not more than the maximum length Lmax of single ice melting, the ice melting section adopts a series ice melting connection mode, and the series ice melting connection mode comprises a first series ice melting connection mode and a second series ice melting connection mode;
according to the length L1 of the ice melting section of the selected ground wire, if the L1 is shorter, namely the L1 is smaller than Lmax, the ice melting section adopts a first series ice melting connection mode, as shown in figure 2, two ground wires are respectively connected to the anode and the cathode of an ice melting power supply through an anode temporary overlapping wire 1 and a cathode temporary overlapping wire 2 at the starting end of the ice melting section, and the two ground wires are connected in a lap joint mode through a series connection wire 3 at the tail end of the ice melting section to form a series circuit;
according to the length L2 of the ice melting section of the selected ground wire, if the L2 is shorter, namely the L2 is smaller than Lmax, the ice melting section adopts a second series ice melting connection mode, as shown in figure 3, one of two ground wires is connected to the anode and the cathode of an ice melting power supply through an anode temporary overlapping wire 1 and a cathode temporary overlapping wire 2 at any point in the ice melting section, the ground wires on two sides of the ice melting power supply connected to the ground wires are subjected to separation treatment, namely the ground wires on two sides of the ice melting power supply point connected to the ice melting power supply point are not communicated, and the two ground wires are respectively connected in a lap joint mode through a series connection wire 3 at the starting end and the tail end of the ice melting section to form a series loop.
When the ice melting section adopts a series ice melting connection mode, the total resistance of the ice melting section is the sum of the resistance values of two ground wires in the ice melting section in the section.
According to the length L3 of the ice melting section of the selected ground wire, if L3 is longer, namely L3 is larger than Lmax and smaller than 2Lmax, the ice melting section adopts a parallel ice melting connection mode, as shown in figure 4, the resistance midpoints of two ground wires in the ice melting section are respectively connected to the anode and the cathode of an ice melting power supply through an anode temporary overlapping wire 1 and a cathode temporary overlapping wire 2, and the two ground wires are respectively connected in an overlapping mode through a series connection wire 3 at the starting end and the tail end of the ice melting section to form a parallel loop.
When the ice melting section adopts a parallel ice melting connection mode, the total resistance of the ice melting section is half of the sum of the resistance values of two ground wires in the ice melting section.
When the ice melting section adopts a parallel ice melting connection mode, the ice melting section can be subjected to single-side ice melting according to the severe ice coating condition, namely if only the ground wire at the severe ice coating side in the ice melting section is needed, the serial line at the ground wire end of the side is connected, and meanwhile, the serial line at the ground wire end of the non-ice melting side is disconnected; namely, the two ground wires are connected in a lap joint mode through the serial line at the starting end of the ice melting section, and the two ground wires at the tail end of the ice melting section are not connected, or the two ground wires are connected in a lap joint mode through the serial line at the tail end of the ice melting section, and the two ground wires at the starting end of the ice melting section are not connected.
S5, calculating the ice melting capacity range and the ice melting voltage range required by each section according to the ice melting wiring mode of the ground wire selected by the ice melting section, and determining the rated current, the rated voltage and the rated capacity of the ice melting power supply;
in S5, when the ice melting section adopts a series ice melting connection mode, the ice melting voltage range of the section is IminR-ImaxR, and the ice melting capacity range is Imin 2 R～Imax 2 R, the rated current required by the ice melting power supply is Imax, the rated voltage is ImaxR, and the rated capacity is Imax 2 R；
When the ice melting section adopts a parallel ice melting connection mode, the section is meltedThe ice voltage range is IminR-ImaxR, and the ice melting capacity range is 2Imin 2 R～2Imax 2 R, the rated current and the rated voltage required by the ice melting power supply are respectively 2Imax and ImaxR, and the rated capacity is 2Imax 2 R；
And Imin is the minimum value of the ground wire ice melting current obtained in S2, imax is the maximum value of the ground wire ice melting current obtained in S2, and R is the total resistance of the ice melting section.
And selecting the ice melting power supply according to the actual condition of the line site and the rated current, the rated voltage and the rated capacity required by the ice melting power supply obtained in the step S5, wherein the ice melting power supply comprises a movable ice melting vehicle, a fixed ice melting device under a newly-added line and an ice melting power supply device in a transformer substation near the lap joint of the newly-built ice melting connecting line.
The lap joint of the ice melting section ground wire and the ice melting power supply needs to consider that when the lead is not powered off, the induction voltage exists on the fully insulated ground wire.
The ground line induced voltage refers to induced voltage generated on the ground line due to electrostatic induction or harmonic wave influence of the conducting wire in different running states when the ground line is insulated and has no ground point. When the ground wire melts ice, the ground wire forms an insulated ice melting loop, and the induction voltage has influence on the access and the starting of the ice melting power supply. Therefore, the induced voltage suppression device is additionally arranged on the ground wire, and the reliable lap joint of the ice melting power supply and the ground wire is guaranteed.
S6, insulators are additionally arranged on the ground wire suspension string and the strain insulator string, and an insulating drainage wire clamp is additionally arranged on the drainage wire, so that the insulation transformation of the ground wire is realized;
the ground wire of a general line adopts a mode of tower-by-tower grounding or sectional insulation one-point grounding, the ground wire of an ice melting section must be insulated to realize ice melting, insulators are additionally arranged on a ground wire suspension string and a strain insulator string, and a duplex insulator string is preferably used when the ground wire is insulated; the drainage of the ground wire and the optical cable in the iron tower adopts an insulation drainage wire clamp, so that the insulation of the ground wire (optical cable) and the iron tower in the ice melting section is ensured;
the insulation level of the ground wire insulator needs to be matched with the ice melting voltage value of the ground wire, so that the total length of the insulator string is shortened as much as possible while the ground wire is insulated.
S7, additionally arranging arc attracting corners on insulators of the ice melting suspension string and the strain insulator string of the ground wire;
the insulator of the ice melting suspension string and the tension string of the ground wire is additionally provided with the arcing horn, and when in lightning stroke, the discharge gap of the arcing horn is broken down in the stage of the pre-discharge of the lightning so as to lead the ground wire to be in a grounding state, thereby not influencing the lightning protection function; when the conducting wire has ground fault, the ground wire gap breaks down to play a role in shunting.
And S6, after the ground wire is subjected to insulation transformation, grounding at least one point of the ground wire in the ice melting section when the ice is not melted, and disconnecting the grounding point to form an insulation loop when the ice is melted, so that the influence on the lightning protection performance of the line after the insulation transformation of the ice melting of the ground wire is further reduced.
And S8, selecting a proper wiring mode and an ice melting power supply according to the steps, connecting the ground wire induction voltage suppression device, and performing ground wire ice melting operation after the ground wire and the ice melting power supply are lapped.
A second embodiment of the present invention provides a method for melting ice on a ground wire without power failure for a wire, and on the basis of the first embodiment, as shown in fig. 1 to 8, the method specifically includes the following steps:
s1, determining an ice melting section: collecting the climate characteristic conditions along the investigation line, and mainly carrying out icing investigation on a data relative lack section, an ice-prone area, an ice-heavily covered section and an ice area boundary section, particularly the icing condition in the strong cold tide process in recent years; meanwhile, detailed investigation is carried out on the icing design values and disaster conditions of lines of different grades near the lines, the icing condition, microclimate, micro-topographic point and the like during ice damage are known, and the section of the project needing ground wire deicing is determined.
S2, determining the ice melting current: the ice melting current of the overhead line is related to factors such as environmental temperature, wind speed, ice coating thickness, ice melting time and the like. And selecting an ice melting calculation mathematical model by using the existing mode and the past engineering experience, and calculating ice melting time and critical ice melting current under various conditions. Meanwhile, a related ice melting test is carried out, the ice melting time, the current and the like obtained by theoretical calculation are compared with test parameters to obtain more accurate and reasonable ice melting current and ice melting time, for example, according to the ice melting time of 1 hour, the ice melting current ranges of all the ground wires in the ice melting range when different coated ice is melted are obtained by calculation, and the minimum value Imin and the maximum value Imax of the ice melting current are obtained, which are shown in the following table:
and S3, obtaining the maximum length Lmax of one-time ice melting according to the ice melting current value and the ice melting voltage value limit value, dividing the ice melting range into single or multiple ice melting sections according to the Lmax and the importance (if existing) of single ice melting of the special sections, wherein the length of each section is L1, L2 and L3, 82308230, ln (L1, L2 and L3, 8230; ln is less than or equal to 2 multiplied by Lmax).
When the ice melting current of the ice melting section is as the upper table Imin =200A and Imax =600A, and the ice melting voltage is +/-25 kV (considering that the voltage value of the existing conventional ice melting material and equipment is within +/-25 kV), the total resistance of the ground wires at two sides of the maximum ice melting section is not more than 83 omega (50 kV/0.6 kA), so as to obtain the maximum Lmax (the total resistance of the ground wires at two sides of Lmax is 83 omega) of the ice melting at this time, referring to the line condition, the ice melting division section is as shown in FIG. 8, wherein the length of the ice melting section L1 is L1, and L1 is not more than Lmax; the length of the ice melting section L2 is L2, and L2 is less than or equal to Lmax; the length of the ice melting section L3 is L3, and Lmax is more than or equal to L3 and less than or equal to 2Lmax.
S4, designing a high-efficiency and reliable ground wire ice melting wiring mode of the section according to the lengths of different ice melting sections and the positions of power supply access points;
the length L1 of the ice melting section L1 is less than or equal to Lmax, and the ice melting of the section can be realized by connecting two ground wires in series for one time. Further determining ice melting power supply access points according to the terrain and the landform of the section, and generally comprehensively selecting a tower position with better terrain conditions and smaller ice area, which is more convenient for construction and operation of operators, or a tower position closer to the location of the ice melting device to set the ice melting power supply access points;
if the access point is at the start point or the end point of the ice melting section (taking the access point at the start point as an example), it can be considered that the two ground wires adopt a first series ice melting connection mode, and the total resistance R of the ice melting section 1 Is the sum of the resistance values of the two ground wires;
the length L2 of the ice melting section L2 is less than or equal to Lmax, and the ice melting of the section can be realized by connecting two ground wires in series. Further determining ice melting power supply access points according to the terrain and the landform of the section, and generally comprehensively selecting a tower position with better terrain conditions and smaller ice area, which is more convenient for construction and operation of operators, or a tower position closer to the location of the ice melting device to set the ice melting power supply access points;
if the access point is at any point in the middle of the ice melting section, a second series connection ice melting connection mode can be considered for two ground wires, and the total resistance R of the ice melting section 2 Is the sum of the resistance values of the two ground wires;
the length Lmax of the ice melting section L3 is less than or equal to L3 and less than or equal to 2Lmax, a parallel ice melting connection mode can be considered for two ground wires, the ice melting power supply access point is the middle value of the resistances of the two ground wires in the section, and the total resistance R of the ice melting section b Is half of the sum of the resistance values of the two ground wires.
S5, calculating a de-icing voltage range and a de-icing capacity range required by each section according to a ground wire de-icing wiring mode selected by the de-icing sections, and determining the rated current, the rated voltage and the rated capacity of the de-icing power supply;
the ice melting voltage range of the ice melting section L1 is IminR 1 ～ImaxR 1 The ice melting capacity range is Imin 2 R 1 ～Imax 2 R 1 The rated current and the rated voltage required by the ice melting power supply are Imax and ImaxR respectively 1 Rated capacity of Imax 2 R 1 ；
The ice melting voltage range of the ice melting section L2 is IminR 2 ～ImaxR 2 The ice melting capacity range is Imin 2 R 2 ～Imax 2 R 2 The rated current and the rated voltage required by the ice melting power supply are Imax and ImaxR respectively 2 Rated capacity of Imax 2 R 2 ；
The ice melting voltage range of the ice melting section L3 is IminR b ～ImaxR b The ice melting capacity range is 2Imin 2 R b ～2Imax 2 R b The rated current and the rated voltage required by the ice melting power supply are respectively 2Imax and ImaxR b Rated capacity of 2Imax 2 R b ；
The ice melting section L3 can be operated actuallySelecting a single-side ice melting section to perform independent ice melting under the condition of ice coating on a line site, for example, when an actual cold tide comes temporarily, if only the ground wires of the sections on the left side of a power access point are seriously coated and ice melting is urgently needed, only considering the section on the left side to perform independent ice melting, only keeping the series connection at the end of the ice melting section connected, and simultaneously disconnecting the series connection at the end of the section on the right side which is not subjected to ice melting, wherein the ice melting current is Imin-Imax, and the voltage is IminR b ～ImaxR b Capacity is Imin 2 R b ～Imax 2 R b 。
In summary, the ice melting parameters in the ice melting region are shown in the following table:
selecting an ice melting power supply: the ice melting power supply is selected based on the current, the voltage and the capacity of the ice melting device needed by the ice melting section, and the situation of the ice melting section of the reference line is comprehensively analyzed and considered. If the ice melting section is short, the required ice melting capacity is small, and the position of an access point of an ice melting power supply is easy to reach, a mobile ice melting vehicle can be selected, the ice melting vehicle is driven to the position below the tower position of the access point during ice melting, and the ground wires at two sides are lapped for power supply; if the ice melting section is longer, the required ice melting capacity is larger, or the position of an access point of an ice melting power supply is inconvenient, a fixed ice melting device is newly added under the tower position of the access point, or an ice melting device in a transformer substation near the lap joint of a newly-built ice melting connecting line can be considered.
And S6, in order to melt ice on the ground wire, the ground wire of the ice melting section is required to be insulated, and insulators are required to be additionally arranged on the ground wire suspension string and the strain insulator string, and a composite insulator or a disc insulator can be adopted. The duplex insulator string is preferably used when the ground wire is insulated, the connection between the serial parts is required to be reliable on the premise of shortening the string length as much as possible, and the duplex insulator string can flexibly rotate along the line direction and the vertical line direction without blocking. Fig. 5 shows a common ground wire ice melting insulation series connection mode.
Besides the ground wire suspension string and the strain insulator string, the insulator is additionally arranged, and the insulating drainage wire clamp is also adopted for routing and drainage of the ground wire (optical cable) in the iron tower, so that the insulation of the ground wire (optical cable) and the iron tower in the ice melting section is ensured. And (3) simulating and determining the sag and the length of the ground wire jumper wire in the ice melting section, wherein the electrical distance between the jumper wire and the tower material is not less than 0.2m after the wind deflection is considered, and the gap between the OPGW optical cable and the lower part of the ground wire down to the tower body is not less than 0.3m.
S7, selection of a ground line arcing angle (discharge gap): the arc attracting angle is required to be additionally arranged on the insulators of the ice melting suspension string and the strain insulator of the ground wire, when lightning strikes are carried out, the discharge gap of the arc attracting angle of the ground wire is broken down in the stage of discharging of the precursor of the lightning, so that the ground wire is in a grounding state, the lightning protection function of the ground wire is not influenced, and when the ground fault occurs to the lead, the gap of the ground wire is broken down, so that the shunting effect is achieved.
When the tower or the insulating ground wire is struck by lightning, the arcing angle discharge gap of the ground wire can generate flashover, the lightning triggering effect of the insulating ground wire is not obviously different from the tower-by-tower grounding and sectional grounding ground wires, and when the distance of the air gap between the ground wire and the tower insulation is 60-200 mm, the impact on the counterattack lightning-resistant level of the line is relatively small. Therefore, after the ground wire ice melting insulation string is additionally provided with the arcing angle (the discharge gap is between 60mm and 200 mm), the influence on the electrical property of the line mine can be avoided. Referring to the test conclusion and the past engineering experience, the discharge gap of the ground wire insulator adopts a fixed gap, and the distance value is 60-120 mm.
When the line normally runs, the induction voltage of the insulating ground wire is small, when the line breaks down, the induction voltage on the ground wire is large, meanwhile, in view of the important function of the ground wire on the line lightning protection, after the ground wire of the ice melting section is insulated and transformed, a certain point or certain points of the ground wire section are grounded when the ice is not melted, and the ground point is disconnected to form an insulating loop when the ice is melted.
The ice melting section overhead ground wire is fully insulated and grounded in a single point or multiple points, so that the ground wire at the grounding tower position can be insulated and led down for operation of operators, and then a grounding knife switch is installed for grounding, as shown in fig. 6.
It should be noted that after the ice melting section ground wire is fully insulated, the influence of the induced voltage also needs to be considered when the ground wire and the ice melting power supply device are lapped. When ice is not melted, the ground wire adopts a multipoint grounding mode, and the induction voltage is small and can be ignored; when the ice melting of the ground wire after the wire is stopped is fully insulated, no induction voltage exists on the ground wire. However, in the invention, when the ground wire melts ice, the lead does not stop running, the ground wire is fully insulated to form an ice melting loop, the lead can continuously generate an induction voltage on the ground wire, and the induction voltage has influence on the access and the starting of an ice melting power supply. Therefore, as shown in fig. 7, the ground line induction voltage suppression device is connected in parallel to the ground line, so that the effects of suppressing the induction voltage on the ground line and realizing normal ice melting of the ground line can be achieved.
In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
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.
Claims (10)
1. A method for melting ice on a ground wire without power failure of a lead is characterized by comprising the following steps:
s1, determining a section needing ground wire de-icing according to the partition condition of an engineering ice area, the ground wire model selection condition and the micro-meteorological area of the engineering micro-terrain, and determining the range and the length of the ground wire de-icing;
s2, determining ice melting duration according to the relation between the environmental temperature, the wind speed, the ice coating thickness and the ice melting current, and obtaining the maximum value and the minimum value of the ice melting current of the ground wire;
s3, obtaining the maximum length Lmax of single ice melting according to the ice melting current value limit value, and dividing an ice melting range into a single or a plurality of ice melting sections according to the Lmax;
s4, selecting a ground wire ice melting wiring mode of the section according to the length of the ice melting section and the position of an access point of an ice melting power supply, wherein the ground wire ice melting wiring mode comprises a series connection ice melting wiring mode and a parallel connection ice melting wiring mode;
s5, calculating the ice melting capacity range and the ice melting voltage range required by each section according to the ice melting wiring mode of the ground wire selected by the ice melting section, and determining the rated current, the rated voltage and the rated capacity of the ice melting power supply;
s6, insulators are additionally arranged on the ground wire suspension string and the strain insulator string, and an insulating drainage wire clamp is additionally arranged on the drainage wire, so that the insulation transformation of the ground wire is realized;
s7, additionally arranging arc attracting corners on insulators of the ice melting suspension string and the strain insulator string of the ground wire;
and S8, performing ground wire ice melting operation.
2. The method for melting ice on the ground wire without power failure of the lead according to claim 1, wherein in S4, when the length of the ice melting section is not more than the maximum length Lmax of single ice melting, the ice melting section adopts a series ice melting connection mode, and the series ice melting connection mode comprises a first series ice melting connection mode and a second series ice melting connection mode;
when the ice melting section adopts a first series ice melting connection mode, two ground wires are respectively connected to the anode and the cathode of an ice melting power supply at the starting end of the ice melting section, and the two ground wires are connected in a lap joint mode through a series line at the tail end of the ice melting section to form a series loop;
when the ice melting section adopts a second series ice melting connection mode, one of the two ground wires is connected to the anode and the cathode of the ice melting power supply at any point in the ice melting section, the ground wires on two sides of the ground wire connected to the ice melting power supply are subjected to separation treatment, and the two ground wires are respectively connected in a lap joint manner through the series wires at the starting end and the tail end of the ice melting section to form a series loop.
3. The method for melting ice on ground wires without power failure of the conducting wires as claimed in claim 2, wherein when the ice melting section adopts a series ice melting connection mode, the total resistance of the ice melting section is the sum of the resistance values of two ground wires in the ice melting section.
4. The method for melting ice on the ground wire without power failure of the lead according to claim 1, wherein when the length of the ice melting section is greater than the maximum length Lmax of single ice melting, the ice melting section adopts a parallel ice melting connection mode, the midpoint of the resistance of the two ground wires in the ice melting section is respectively connected to the anode and the cathode of an ice melting power supply, and the two ground wires are respectively connected in a lap joint manner through a series line at the starting end and the tail end of the ice melting section to form a parallel loop.
5. The method for melting ice on the ground wire without power failure of the lead as claimed in claim 4, wherein when the ice melting section adopts a parallel ice melting connection mode, the total resistance of the ice melting section is half of the sum of the resistance values of the two ground wires in the ice melting section.
6. The method for melting ice on the ground wire without power failure of the conducting wire as claimed in claim 5, wherein when the ice melting section adopts a parallel ice melting connection mode, the ice melting section is subjected to unilateral ice melting according to the severe ice coating condition, namely two ground wires are connected in a lap joint mode through a serial line at the starting end of the ice melting section, and two ground wires at the tail end of the ice melting section are not connected, or two ground wires are connected in a lap joint mode through a serial line at the tail end of the ice melting section, and two ground wires at the starting end of the ice melting section are not connected.
7. The method for melting ice on the ground wire without power failure of the lead according to any one of claims 1 to 6, wherein in S5, when the ice melting section adopts a series ice melting connection mode, the ice melting voltage range of the section is IminR-ImaxR, and the ice melting capacity range is Imin 2 R～Imax 2 R, the rated current required by the ice melting power supply is Imax, the rated voltage is ImaxR, and the rated capacity is Imax 2 R；
When the ice melting section adopts a parallel ice melting connection mode, the ice melting voltage range of the section is IminR-ImaxR, the ice melting capacity range is 2 IminR-2 ImaxR, the rated current required by an ice melting power supply is 2Imax, the rated voltage is ImaxR, and the rated capacity is 2ImaxR;
and Imin is the minimum value of the ground wire ice melting current obtained in S2, imax is the maximum value of the ground wire ice melting current obtained in S2, and R is the total resistance of the ice melting section.
8. The method for melting ice on the ground wire without power failure of the wire according to any one of claims 1 to 6, further comprising:
and selecting the ice melting power supply according to the actual condition of the line site and the rated current, the rated voltage and the rated capacity required by the ice melting power supply obtained in the step S5, wherein the ice melting power supply comprises a movable ice melting vehicle, an offline fixed ice melting device and an ice melting power supply in a transformer substation.
9. The method for deicing the ground wire without power failure of the lead according to any one of claims 1 to 6, further comprising: an induced voltage suppression device is additionally arranged on the ground wire.
10. The method for melting ice on the ground wire without power failure of the conducting wire according to any one of claims 1 to 6, wherein in S6, after the transformation of the insulation of the ground wire, at least one point of the ground wire in the ice melting section is grounded when the ice is not melted, and the grounding point is disconnected to form an insulation loop when the ice is melted.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211653786.8A CN115882412A (en) | 2022-12-22 | 2022-12-22 | Ice melting method for ground wire of wire without power failure |
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| CN202211653786.8A CN115882412A (en) | 2022-12-22 | 2022-12-22 | Ice melting method for ground wire of wire without power failure |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117175523A (en) * | 2023-11-03 | 2023-12-05 | 中国电力工程顾问集团西南电力设计院有限公司 | Method for inhibiting ice melting induced voltage of earth wire of uninterrupted AC line |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117175523A (en) * | 2023-11-03 | 2023-12-05 | 中国电力工程顾问集团西南电力设计院有限公司 | Method for inhibiting ice melting induced voltage of earth wire of uninterrupted AC line |
| CN117175523B (en) * | 2023-11-03 | 2024-01-26 | 中国电力工程顾问集团西南电力设计院有限公司 | Method for inhibiting ice melting induced voltage of earth wire of uninterrupted AC line |
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