CN111463736A - Direct ground wire grounding ice melting method - Google Patents
Direct ground wire grounding ice melting method Download PDFInfo
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- CN111463736A CN111463736A CN202010382320.3A CN202010382320A CN111463736A CN 111463736 A CN111463736 A CN 111463736A CN 202010382320 A CN202010382320 A CN 202010382320A CN 111463736 A CN111463736 A CN 111463736A
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- ice melting
- ground wire
- tower
- ground
- wire
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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
- H02G7/16—Devices for removing snow or ice from lines or cables
Abstract
A direct ground connection ice melting method of ground wire, after short circuit of ground wire and optical cable of head end of ice melting section, insert the anodal of the ice melting apparatus; after the ground wire at the tail end of the ice melting section is short-circuited with the optical cable, the ice melting section is connected with the tail end of any phase of wire; the head end of the lead is connected with the negative pole of the ice melting device to form a loop. The ice melting device outputs direct current, one part of the direct current flows into an ice melting section through the ground wire and the optical cable, the other part of the direct current flows into the ground through the tower, and finally the direct current is collected to the lead and flows back to the negative electrode of the ice melting device. The invention adopts a wiring mode of 'ground wire removing and wire returning', overcomes the influence of tower shunt, and leads the ice melting current on the ground wire to reach a certain value, thereby achieving the purpose of ice melting. The problem of high operation and maintenance cost due to the installation of the insulator is solved on the premise of ensuring the ice melting efficiency.
Description
Technical Field
The invention relates to the technical field of deicing of ground wires in power transmission line engineering, in particular to a direct ground-connection deicing method for the ground wires.
Background
The ice coating of the transmission line in winter seriously threatens the safe operation of the power system. In 2008, ice disaster causes large-area power failure in south, and a serious challenge is provided for reliable operation and maintenance of a power system. At present, ice melting methods of the ground wire are different and comprise alternating current short circuit ice melting and direct current ice melting. The basic principle of the direct-current ice melting device is that the converter valve is adopted to convert alternating current into direct current, the direct current is injected into an alternating-current wire, and the direct current is utilized to generate heat in a wire resistor to melt covered ice. However, due to the influence of the operating conditions of the ground wire, the ice melting mode of the ground wire is that the insulator is arranged between the ground wire and the tower, so that the ice melting current of the ground wire is prevented from flowing into the ground through the tower, but the insulation method can greatly improve the operation and maintenance cost and is complex to operate. It is for these reasons that ice melting of the ground wire is an issue that has not yet been fully solved in power transmission lines.
In the existing ground wire ice melting method, in order to improve the ice melting efficiency of the ground wire, an insulator is usually installed between the ground wire and a tower, so that the ground wire is connected with the tower through the insulator, thereby isolating the electrical connection between the ground wire and the tower and preventing the ice melting current on the ground wire from entering the ground through the tower. However, the installation of the insulator between the ground wire and the tower increases the operation and maintenance cost of the line, increases the workload of workers, and causes resource waste.
Such as: chinese patent 'a method for melting ice on circuitous series ground wires of power transmission line': CN201610704381.0 proposes a method for melting ice of an 'circuitous series connection' ground wire, the invention connects three ground wires of an ice melting section in series, and solves the problem of replacing the ground wires of a single loop and a double loop on the premise of ensuring the safety and the reliability of a power transmission line. However, the technical scheme is complex to operate and high in operation and maintenance cost.
Disclosure of Invention
The invention provides a direct ground ice melting method for a ground wire, which does not install an insulator between the ground wire and a tower, adopts a wiring mode of 'ground wire going and wire returning', overcomes the influence of tower shunting, and enables the ice melting current on the ground wire to reach a certain value, thereby achieving the purpose of ice melting. The problem of high operation and maintenance cost due to the installation of the insulator is solved on the premise of ensuring the ice melting efficiency.
The technical scheme adopted by the invention is as follows:
a direct ground connection ice melting method of ground wire, after short circuit of ground wire and optical cable of head end of ice melting section, insert the anodal of the ice melting apparatus; after the ground wire at the tail end of the ice melting section is short-circuited with the optical cable, the ice melting section is connected with the tail end of any phase of wire; the head end of the lead is connected with the negative pole of the ice melting device to form a loop;
the ice melting device outputs direct current, one part of the direct current flows into an ice melting section through the ground wire and the optical cable, the other part of the direct current flows into the ground through the tower, and finally the direct current is collected to the lead and flows back to the negative electrode of the ice melting device.
The ice melting distance is shortened, the shorter the distance, the smaller the shunt is, the long-distance ice melting ground wire can be subjected to ground wire ice melting in a segmented mode.
The ice melting output current of the head end is increased, and the size of the ground wire current of the middle section can be increased under the condition that the shunt coefficient is not changed.
And the tower grounding down lead is disconnected, the size of the tower grounding resistance value is increased, and the tower shunt is reduced.
The invention relates to a direct ground ice melting method for a ground wire, which has the advantages that:
1: normally, the ground wire is short in icing and waving section, direct-current deicing can be carried out on the short-distance direct grounding type ground wire by combining a light movable deicing device (small capacity and large current output), the operation and wiring are flexible and convenient, and the direct-current deicing device is suitable for power transmission lines of 500kV and below.
2: the ground wire is not required to be subjected to large-scale insulation transformation, a large amount of line operation and maintenance funds are saved, and the economic benefit is remarkable.
3: by adopting the wiring mode of 'ground wire removing and wire returning', the ice melting efficiency of the ground wire can be greatly improved and the ice melting operation and maintenance cost of the ground wire can be reduced on the premise of ensuring the safety and the reliability of the power transmission line.
Drawings
Fig. 1 is a schematic diagram of direct grounding type ground current and tower shunt.
FIG. 2 is a diagram of the distribution of the line current in the ice melting section.
FIG. 3 is a wiring diagram for ice melting of the ground wire and the optical cable.
Detailed Description
Aiming at a single-double-circuit hybrid transmission line, the invention provides a direct ground connection ice melting method of a ground wire, which comprises the steps of connecting a ground wire at the head end of an ice melting section and an optical cable into the anode of an ice melting device after short circuit; after the ground wire at the tail end of the ice melting section is short-circuited with the optical cable, the ice melting section is connected with the tail end of any phase of wire; the head end of the lead is connected with the negative pole of the ice melting device to form a loop; the ice melting device outputs direct current, one part of the direct current flows into an ice melting section through the ground wire and the optical cable, the other part of the direct current flows into the ground through the tower, and finally the direct current is collected to the lead and flows back to the negative electrode of the ice melting device.
The split flow diagram of the direct grounding type ground current and tower is shown in figure 1, I0、I1、I2、......、In-2、In-1、InIs the direct current flowing through each segment of ground. I isf1、If2、If3、......、If(n-2)、......、If(n-1)、IfnThe direct current flowing through each base tower is divided.
It should be noted that, near the head end, the ice melting current is shunted by the tower, and the direct current flowing through the ground wire is gradually reduced; and at the position close to the tail end, the shunt current flows back to the tower through the ground and is converged to the ground wire. In the ice melting section of the ground wire, the current of the ground wires at the head end and the tail end is large, and the current of the ground wire at the middle position is small, as shown in fig. 2. To ensure the ice melting current I of the ground wire at the middle position of the ice melting sectionminLarge enough, the following measures can usually be taken:
1) the ice melting distance is shortened, the shorter the distance is, the smaller the shunt is, the ground wire ice melting can be carried out on the long-distance ice-coated ground wire in a segmented mode;
2) the ice melting output current of the head end is increased, and the size of the ground wire current of the middle section can be increased under the condition that the shunt coefficient is not changed;
3) and disconnecting the tower grounding downlead, increasing the size of the tower grounding resistance value and reducing tower shunt.
Example (b):
7 months from 19 days to 20 days in a year, 500kV Doujiang secondary loop wire and ground wire ice melting tests are carried out by a provincial organization and maintenance company of a certain power-saving limited company of a national grid and a power supply company of a certain city, and the line length is 3.1km, so that the success is achieved. In the process of the ground wire ice melting test, the wiring mode is adopted, the influence of tower shunt is overcome, and the difficulty of direct grounding type ground wire ice melting is solved.
Test conditions:
the ice melting direct current rises from 0A to 800A, which is equal to the current of the head end and the tail end, and the temperature of the ground wire of the No. 4 tower rises by 1.3 ℃ through the infrared detection on the tower; the direct current rises to 1000A, and the temperature of the ground wire rises by 3.0 ℃ cumulatively; the DC current output rises to 1500A, the ice melting current of the ground wire close to the middle position is measured to reach 300A, and the accumulated temperature of the ground wire rises to 13 ℃.
And (4) test conclusion:
(1): the ground wires are connected with the optical cable in parallel, and when the output current of the ice melting device 1 reaches 1500A, the minimum current of a single ground wire reaches 300A;
(2): when the ice melting current exceeds 300A, the temperature rise effect of the ground wire is obvious;
(3): after the ground wire is directly grounded through the tower, the shunting of the tower is large, ice melting can be carried out by adopting a 'ground wire going and conducting wire returning' mode, and meanwhile, in order to reduce the shunting loss as much as possible, the ground wire is disconnected at a strain section outside an ice melting section as much as possible, and a tower grounding down lead is disconnected;
(4): through the ground wire ice melting test, the direct-current ice melting can be carried out on the ground wire directly grounded in a short distance through the light movable ice melting device, the large-scale insulation transformation of the ground wire is not needed, a large amount of line transformation funds can be saved, and the economic benefit is remarkable.
The test results show that the invention is consistent with the expected effect and is feasible.
Description of the wiring situation:
(1) the power line 2 required by ice melting adopts a distribution line under a 500kV Doujiang secondary circuit line and is accessed in a live working mode;
(2) the ice melting device 1 is a vehicle-mounted light mobile ice melting device, the capacity is 4000kVA, the maximum output current is 4000A, the alternating current input is connected to a 10kV distribution line through a cable, and the direct current output is connected to a ground wire and an optical cable through a direct current cable;
(3) and (3) short-circuiting the ground wire and the optical cable of the head end 1# tower from the ice melting section L, namely the 1# tower to the n # tower, then connecting the short-circuited ground wire and the optical cable with the phase line B, outputting current from the positive direct current of the ice melting device 1, and enabling the current to flow into the ground wire and the optical cable through the cable, the ground wire connecting wire and the like hung on the phase B, namely 'ground wire removing'.
And after the ground wire and the optical cable of the n # tower are short-circuited at the tail end of the ice melting section L, the ground wire and the optical cable are connected with a side phase C phase line, and current flows into the n # tower at the tail end of the ice melting section through the ground wire and the optical cable, then flows back through the C phase wire and enters the negative pole of the ice melting device 1 through the cable hung on the C phase of the 1# tower at the head end of the ice melting section, namely the wire return.
(4) In the ice melting process, the current of the ground wire and the temperature of the wire need to be monitored to prevent the contact of the ground wire from heating or fusing.
Claims (4)
1. A deicing method by directly grounding a ground wire is characterized in that: after the ground wire and the optical cable at the head end of the ice melting section are in short circuit, the anode of the ice melting device (1) is accessed; after the ground wire at the tail end of the ice melting section is short-circuited with the optical cable, the ice melting section is connected with the tail end of any phase of wire; the head end of the lead is connected with the negative electrode of the ice melting device (1) to form a loop;
the ice melting device (1) outputs direct current, one part of the direct current flows into an ice melting section through a ground wire and an optical cable, the other part of the direct current flows into the ground through a tower, and finally is collected to a lead and flows back to the negative electrode of the ice melting device (1).
2. The deicing method by directly grounding the ground wire as claimed in claim 1, wherein: the ice melting distance is shortened, the shorter the distance, the smaller the shunt is, the long-distance ice melting ground wire can be subjected to ground wire ice melting in a segmented mode.
3. The deicing method by directly grounding the ground wire as claimed in claim 1, wherein: the ice melting output current of the head end is increased, and the size of the ground wire current of the middle section can be increased under the condition that the shunt coefficient is not changed.
4. The deicing method by directly grounding the ground wire as claimed in claim 1, wherein: and the tower grounding down lead is disconnected, the size of the tower grounding resistance value is increased, and the tower shunt is reduced.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010382320.3A CN111463736A (en) | 2020-05-08 | 2020-05-08 | Direct ground wire grounding ice melting method |
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| CN202010382320.3A CN111463736A (en) | 2020-05-08 | 2020-05-08 | Direct ground wire grounding ice melting method |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102611061A (en) * | 2012-03-13 | 2012-07-25 | 云南电力试验研究院（集团）有限公司电力研究院 | Single-pole ground loop type direct-current deicing method for overhead ground wire and OPGW (optical fiber composite overhead ground wire) |
| CN103326299A (en) * | 2013-05-27 | 2013-09-25 | 南方电网科学研究院有限责任公司 | Method for starting direct-current deicing system of overhead ground wire and compound optical fiber ground wire |
| CN105262001A (en) * | 2015-11-24 | 2016-01-20 | 国网四川省电力公司电力科学研究院 | Ice melting method for overhead ground wire of power transmission line |
| CN105529667A (en) * | 2016-02-23 | 2016-04-27 | 徐光武 | DC ice melting system and DC ice melting method for UHV ground wires |
-
2020
- 2020-05-08 CN CN202010382320.3A patent/CN111463736A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102611061A (en) * | 2012-03-13 | 2012-07-25 | 云南电力试验研究院（集团）有限公司电力研究院 | Single-pole ground loop type direct-current deicing method for overhead ground wire and OPGW (optical fiber composite overhead ground wire) |
| CN103326299A (en) * | 2013-05-27 | 2013-09-25 | 南方电网科学研究院有限责任公司 | Method for starting direct-current deicing system of overhead ground wire and compound optical fiber ground wire |
| CN105262001A (en) * | 2015-11-24 | 2016-01-20 | 国网四川省电力公司电力科学研究院 | Ice melting method for overhead ground wire of power transmission line |
| CN105529667A (en) * | 2016-02-23 | 2016-04-27 | 徐光武 | DC ice melting system and DC ice melting method for UHV ground wires |
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Application publication date: 20200728 |
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