CN102780193B - A kind of power transmission line overhead ground wire electric current de-icing method - Google Patents

Abstract

A current melting method for overhead ground wires of power transmission lines, which mainly includes the following steps: use the ground wire insulators to insulate each overhead ground wire, and ground them through a grounding knife switch. When the power transmission line is in normal operation, the The overhead ground wire is reliably grounded through the closed grounding knife switch. When the ice is melted, the grounding knife switch is disconnected, and the overhead ground wire is insulated from the ground; The power transmission wires are short-circuited by a short wire, and the start of the overhead ground wire that needs to be melted is connected to the other overhead ground wire near it or the out-of-service transmission wire to the ice-melting power supply to form The ice-melting circuit turns on the ice-melting power supply, generates an ice-melting current in the ice-melting circuit, and uses the current to do work and generate heat to melt the ice. The method of the invention is used to load the ice-melting current on the overhead ground wire to increase the self-heating temperature of the overhead ground wire, thereby effectively melting the ice on it.

Description

A current melting method for overhead ground wires of transmission lines

technical field

The invention relates to a current melting method for overhead ground wires of power transmission lines, which is applicable to power transmission lines with a single overhead ground wire or two overhead ground wires.

Background technique

The current of the overhead ground wire of the transmission line is much smaller than that of the transmission wire, so it is easier to be iced. The sag of the overhead ground wire after ice coating becomes larger, which cannot meet the sag requirements of the transmission line for its overhead ground wire. When the wind blows and dances, flashovers are prone to occur between the transmission wires of the transmission line and the overhead ground wire. Make the transmission line trip, affect the normal operation of the transmission line, and may damage the transmission line. In addition, if the spans at both ends of the tower are not equal or the tower is located in a mountainous area, the overhead ground wire will be covered with ice, which will cause the tower to be unbalanced in force, which will easily cause the danger of the tower head being bent, deformed or even broken. In severe cases, the tower may tilt or collapse.

Overhead ground wires are mainly divided into ordinary overhead ground wires such as steel strands or good conductor ground wires and optical fiber composite overhead grounds, referred to as OPGW. It has the dual functions of ground wire and communication optical cable, and generally adopts the grounding method of base-by-base grounding. For overhead ground wires that are grounded base by base, it is difficult to achieve direct current melting of overhead ground wires. Sometimes in order to melt the ice of the overhead ground wire, it is even necessary to remove the original overhead ground wire and erect a new line. Also have mechanical deicing method, passive deicing method etc., but deicing effect is all poor.

Contents of the invention

The technical problem to be solved by the present invention is to propose a new method of melting ice for overhead ground wires of power transmission lines. By using the method of melting ice of the present invention, it is possible to effectively melt ice for overhead ground wires and avoid The flashover of the transmission line and the deformation of the iron tower caused by the problem occur, and the overhead ground wire does not need to be removed when the ice is melted. The method is convenient to implement and has a wide range of applications.

The technical problem to be solved by the present invention is realized through the following technical solutions:

A current melting method for overhead ground wires of transmission lines, characterized in that it comprises the following steps:

S1) According to the icing degree of the overhead ground wire, determine the length of the overhead ground wire that needs to be ice-melted, determine the voltage of the ice-melting power supply, select a ground wire insulator with appropriate mechanical strength, and determine its protective gap distance d;

S2) Use the ground wire insulator to insulate each overhead ground wire, and ground them through the grounding switch. When the transmission line is in normal operation, the overhead ground wire is reliably grounded through the closed grounding switch. The ground switch is disconnected, and the overhead ground wire is insulated from the ground;

S3) Short-circuit the end of the overhead ground wire that needs to be melted with another nearby overhead ground wire or an out-of-service transmission wire through a short wire, and connect the beginning of the overhead ground wire that needs to be melted with the nearby Another overhead ground wire or the out-of-service power transmission wire is connected to the ice-melting power supply to form an ice-melting circuit, and the ice-melting power supply is turned on to generate an ice-melting current in the ice-melting circuit, and use the current to do work Heat to melt ice.

For the lines with segmented insulation of the overhead ground wire, when melting the ice of the overhead ground wire, each adjacent segment of the overhead ground wire within the determined ice-melting range shall be connected through a jumper wire to form an ice-melting circuit . For lines with full-line insulation or single-point grounding with full-line insulation, there is no need to use jumper wires because there is no segment point in the middle of the line.

The step S1) is specifically implemented through the following steps:

S1.1) Select ground wire insulators with appropriate mechanical strength according to their load, material requirements and installation method;

S1.2) Select the ice-melting power supply voltage according to the icing degree of the overhead ground wire and the ice-melting length;

S1.3) Determine the protective gap distance d of the ground wire insulator according to the ice-melting power supply voltage;

S1.4) Determine whether the discharge voltage of the protective gap distance d is less than the flashover voltage of the ground wire insulator;

S1.5) If step S1.4) is not established, reduce the ice-melting power supply voltage and ice-melting length, and return to step S1.3); if step S1.4) is established, determine the ground wire insulator protective gap distance as d.

The type of the short wire is the same as that of the overhead ground wire, and the type of the overhead ground wire is the same as that of the other overhead ground wire.

The ice-melting power supply is a DC ice-melting power supply or an AC ice-melting power supply.

Compared with the prior art, the present invention has the following beneficial effects:

①It can effectively melt the ice of the overhead ground wire: the method of the present invention is used to load the ice-melting current on the overhead ground wire to make the overhead ground wire self-heating, and the temperature rises, thereby effectively melting the ice on it, and can effectively avoid the damage caused by the overhead ground wire Problems such as transmission line flashover and iron tower deformation caused by ice coating, and when melting ice, there is no need to remove the overhead ground wire, which is convenient for implementation; Solving the problem of icing on overhead ground wires is conducive to ensuring the normal operation of the power system during ice periods;

2. Wide range of application: the method of the present invention considers the situation of having only a single overhead ground wire and two overhead ground wires, and is applicable to overhead lines of different voltage levels; Grounding, segmented insulation single-point grounding, etc., have a wide range of applications;

③Low cost: Compared with losses such as line outage, transmission line burning, and iron tower damage caused by icing on overhead ground wires, the cost of accessories used in the ice-melting method of the present invention is lower.

Description of drawings

Fig. 1 is a block flow diagram of step S1) of the present invention;

Fig. 2 is the structural representation of the grounding of the overhead ground wire insulation lead through the grounding knife switch of the present invention;

Figure 3 is a schematic diagram of the structure of two adjacent overhead ground line segments connected by a jumper wire;

Fig. 4 is a structural schematic diagram of a single overhead ground wire-conductor melting ice connection mode;

Figure 5 is a schematic diagram of the structure of two overhead ground wires for ice-melting wiring.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

Figure 1 is a specific flow chart of step S1) of the present invention. Step S1) mainly needs to determine the length of ice-melting overhead ground wires that need to be ice-melted, determine the voltage of the ice-melting power supply, select a ground wire insulator with appropriate mechanical strength, and determine its protection. Gap distance d, the specific steps are as follows:

S1.1) Select ground wire insulators with appropriate mechanical strength according to their load, material requirements and installation method;

S1.2) Select the ice-melting power supply voltage according to the icing degree of the overhead ground wire and the ice-melting length;

S1.3) Determine the protective gap distance d of the ground wire insulator according to the ice-melting power supply voltage;

S1.4) Determine whether the discharge voltage of the protective gap distance d is less than the flashover voltage of the ground insulator, and note that the discharge voltage of the protective gap distance d and the flashover voltage of the ground insulator need to consider its dry and wet conditions;

S1.5) If step S1.4) is established, determine the protective gap distance of the ground wire insulator as d, if step S1.4) is not established, then reduce the ice-melting power supply voltage and ice-melting length, because the protective gap distance d and ice-melting The power supply voltage is closely related, here the ice melting power supply voltage is reduced, so the protective gap distance d of the ground wire insulator should be correspondingly reduced, and re-judgment, that is, return to step S1.3). In this embodiment, the ice-melting power supply is a DC ice-melting power supply.

Figure 2 is a schematic diagram of the structure of the overhead ground wire insulation lead. The overhead ground wire 2 is supported by the ground wire tension insulator at the cross arm of the strain tower, and each overhead ground wire 2 is respectively connected by the ground wire insulator 1. Insulated and grounded through the grounding switch 3. When the transmission line is in normal operation, the overhead ground wire 2 is reliably grounded through the closed grounding switch 3. When the ice is melted, the grounding switch 3 is disconnected, and the overhead ground wire 2 is insulated from the ground. .

As shown in FIG. 3 , for a circuit in which the overhead ground wire 2 is section-insulated, that is, the entire overhead ground wire 2 is divided into several sections, and the insulation between each section is disconnected and grounded respectively. If the selected ice-melting length includes more than one above-mentioned overhead ground wire segment, the jumper wire 4 can be connected with the overhead ground wire segment adjacent to each segment by using parallel ditch clamp 7 so as to form an ice-melting circuit.

Figures 4 and 5 are the structural schematic diagrams of a single overhead ground wire-conductor deicing connection mode and the structural diagrams of two overhead ground wire deicing wiring modes, respectively. Among them, the single overhead ground wire-conductor deicing connection mode and the two overhead ground wire deicing wiring mode are respectively applicable to transmission lines with only one overhead ground wire and transmission lines with two or more overhead ground wires.

As shown in Figure 4, when operating the overhead ground wire 2 to melt ice, disconnect the grounding knife switch 3 on the lower end of the grounding lead of the overhead ground wire 2, connect two adjacent overhead ground wire segments within the ice-melting range through the jumper wire 4, and connect the The right end of the ice-melting section of the overhead ground wire 2 and the nearby out-of-service transmission conductor 5 are short-circuited through the short-circuit wire 6, and the left end and the nearby out-of-service transmission conductor 5 are connected to the DC ice-melting power supply 8 to form an ice-melting circuit , turn on the DC ice-melting power supply 8, generate ice-melting current in the ice-melting circuit, make the overhead ground wire 2 generate heat by itself, and achieve the purpose of ice-melting.

As shown in Figure 5, when melting ice, disconnect the grounding knife switch 3 on the lower end of the two overhead ground wires 2, 2' and disconnect the two wires on the two overhead ground wires 2, 2' respectively within the ice-melting range. The overhead ground wire segments adjacent to the segment are respectively connected by jumper wires 4 and 4ˊ using parallel trench clamps, and the right ends of the two overhead ground wires 2 and 2ˊ are short-circuited through the short wire 6 of the same type as the overhead ground wire, and their left ends are connected to The DC ice-melting power supply 8 forms an ice-melting loop. This kind of wiring method does not need to stop the transportation of electric wires. The DC ice-melting power supply 8 of the present invention can also be replaced by an AC ice-melting power supply.

Claims (3)

1. a power transmission line overhead ground wire electric current de-icing method, is characterized in that, comprises the steps:

S1) determine the ice-melt length of the overhead ground wire needing ice-melt according to overhead ground wire ice coverage degree, determine the voltage of ice-melt power supply, selection has the ground insulator of suitable mechanical strength and determines its portable protective gaps distance d;

S2) under using described ground insulator every bar overhead ground wire insulation to be drawn respectively, and by grounding switch ground connection, when transmission line normally runs, described overhead ground wire is by closed grounding switch reliable ground, during ice-melt, grounding switch disconnects, overhead ground wire insulation against ground;

S3) will the end of the overhead ground wire of ice-melt and another overhead ground wire near it or the transmission pressure of having stopped transport be needed by shorting stub short circuit, and another overhead ground wire needed near the top of the overhead ground wire of ice-melt and described its or the described transmission pressure of having stopped transport are accessed described ice-melt power supply form ice-melt loop, open described ice-melt power supply, in described ice-melt loop, produce ice melting current, utilize current work heating ice-melt;

Being the circuit of graded insulation for overhead ground wire, when carrying out overhead ground wire ice-melt, being communicated with the adjacent overhead ground wire section of on each bar overhead ground wire within the scope of determined ice-melt each section by jumper to form ice-melt loop;

Described step S1) realize as follows:

S1.1) ground insulator with suitable mechanical strength is selected according to its load, material requirements and mounting means;

S1.2) ice-melt supply voltage is selected according to overhead ground wire ice coverage degree and ice-melt length;

S1.3) according to the portable protective gaps distance d of described ice-melt supply voltage determination ground insulator;

S1.4) judge whether the discharge voltage of portable protective gaps distance d is less than the flashover voltage of ground insulator;

S1.5) if step S1.4) be false, then reduce ice-melt supply voltage and ice-melt length, return step S1.3); If step S1.4) set up, determine that ground insulator portable protective gaps distance is for d.

2. power transmission line overhead ground wire electric current de-icing method according to claim 1, is characterized in that, described shorting stub model is identical with above-mentioned overhead ground wire.

3. power transmission line overhead ground wire electric current de-icing method according to claim 1, is characterized in that, described ice-melt power supply is DC ice melting power supply or exchanges ice-melt power supply.