CN102780176B - Method for reducing insulation overhead ground wire induction voltage of alternating current transmission line - Google Patents

Abstract

A method for reducing the induced voltage of the isolated overhead ground wire of an AC transmission line, comprising the steps of: determining the induced voltage limit value U ₀ and the line current I of the isolated overhead ground wire; The transposition pitch of the overhead ground wire is l ₀ = (8~15)*U ₀ /I (km), and the nearest tension tower is selected every l ₀ from the end of the insulated overhead ground wire as the transposition node Perform ground wire transposition or wire transposition; if the grounding point of the insulated overhead ground wire is selected to be between the two ends of the insulated overhead ground wire, the calculated transposition pitch of the insulated overhead ground wire is 2*l ₀ = (16~30)*U ₀ /I (km), starting from one end of the insulated overhead ground wire, select the nearest tension tower as the transposition node every 2*l ₀ for ground wire transposition or wire transposition, and the insulated overhead ground wire The grounding point is set near half a transposition pitch from one of the transposition nodes. The invention can reduce the induced voltage to within the limit value _U0 of the induced voltage set arbitrarily.

Description

A Method for Reducing the Induced Voltage of Insulated Overhead Ground Wires of AC Transmission Lines

technical field

The invention relates to a method for reducing the induced voltage of the insulating overhead ground wire of the AC transmission line, which can reduce the induced voltage of the insulating overhead ground wire of the AC transmission line to within an arbitrary limit value U ₀ .

Background technique

At present, the insulated overhead ground wire mainly adopts the whole line insulation or single point grounding method. When the transmission line overhead ground wire is fully insulated, the induced voltage of the 500kV transmission line insulated overhead ground wire is above 40kV, and the 220kV transmission line is above 30kV. When the insulated overhead ground wire (same as the above-mentioned insulated overhead ground wire) is single-point grounded, the induced voltage on it increases with the increase of the length of the insulated overhead ground wire, and generally can reach thousands of volts. Excessively high induced voltage of insulated overhead ground wires may lead to faults such as misdischarge and burning of the protection gaps of ground wire insulators, and it is also easy to cause wireless interference to external radio signals, and it is also not conducive to live work on the tower.

Although the above-mentioned induced voltage can be reduced by transposition of wires and ground wires, due to the lack of a scientific calculation method for the transposition pitch, there are large differences in the induced voltage values of insulated overhead ground wires in various regions, which limits the protection gap of ground wire insulators. The setting of the distance is inconvenient. If the distance of the protective gap of the ground insulator is not set properly, the protective gap of the ground insulator may be misdischarged, and it may be difficult to extinguish the arc due to the high recovery voltage of the protective gap. In severe cases, the protective gap of the ground insulator may be burned , and even cause the ground wire insulator to burst. In addition, due to the lack of a unified value for the induced voltage of the insulated overhead ground wire, the workers on the tower have a vague understanding of the induced voltage of the overhead ground wire, which may easily lead to safety accidents.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for reducing the induced voltage of the insulating overhead ground wire of the AC transmission line, which can reduce the induced voltage to within the arbitrarily set induced voltage limit value U ₀ .

In order to solve the above technical problems, the present invention provides two methods for reducing the induced voltage of insulating overhead ground wires of AC transmission lines, the first method is only applicable to single-circuit AC transmission lines, and the second method is applicable to single-circuit and double-circuit AC transmission lines on the same tower . The first method is mainly to reduce the induced voltage of the insulated overhead ground wire to the induced voltage limit value U ₀ by setting the transposition pitch of the conductor and the ground wire. The second method is mainly to set the segmental pitch of the insulated overhead ground wire To reduce the induced voltage to within the induced voltage limit value U ₀ . Whether it is the above-mentioned transposition operation or the above-mentioned section operation, the relationship between the induced voltage and the length of the insulated overhead ground wire is used to control the increase in the induced voltage of the insulated overhead ground wire by controlling the node pitch, so the two methods of the present invention belong to A general inventive concept.

The first method for reducing the induced voltage of an AC transmission line insulation overhead ground wire is characterized in that it includes the following steps:

S1) Determine the limit value _U0 of the induced voltage of the insulated overhead ground wire and the line current I;

S2) Select the grounding point of the insulated overhead ground wire at one end of the insulated overhead ground wire or between the two ends of the insulated overhead ground wire:

S2.1) If the grounding point of the insulated overhead ground wire is selected at one end

S2.11) Calculate the transposition pitch of _the insulated overhead ground wire as l ₀ =(8～15)*U ₀ /I(km), and select the nearest resistant The tension tower is used as a transposition node to perform ground wire transposition or conductor transposition;

S2.2) If the grounding point of the insulated overhead ground wire is selected to be between the two ends of the insulated overhead ground wire

S2.21) Calculate the transposition pitch of the insulated overhead ground wire as 2*l ₀ = (16～30)*U ₀ /I(km), and select the nearest every 2*l ₀ from one end of the insulated overhead ground wire The tension pole tower is used as a transposition node for ground wire transposition or wire transposition, and the grounding point of the insulated overhead ground wire is set near half a transposition pitch from one of the transposition nodes.

The above method 1 essentially includes three wiring methods: 1. Transposition of the insulated overhead ground wire, that is, only the transposition of the ground wire; 2. Transposition of the single-circuit transmission line conductor, that is, only the transposition of the conductor; 3. Cooperate with the transposition of the single-circuit transmission conductor, that is, select the ground wire transposition at some transposition nodes, and select the conductor transposition at the other part.

The second method for reducing the induced voltage of an AC transmission line insulation overhead ground wire is characterized in that it includes the following steps:

S1) Determine the limit value _U0 of the induced voltage of the insulated overhead ground wire and the line current I;

S2) Preliminarily choose whether the grounding point of the insulated overhead ground wire is set at the end of each segmented ground wire or in the middle of each segmented ground wire:

S2.1) If the grounding point of the insulated overhead ground wire is selected at the end of each segment ground wire

S2.11) Calculate the segmental pitch of the insulated overhead ground wire _as l ₀ ′=(8～15)*U ₀ /I(km), and select the nearest resistant The tension pole tower is used as a segmented node to segment the ground wire, and the grounding point of the insulated overhead ground wire is set at the same side end of each segmented ground wire;

S2.2) If the grounding point of the insulated overhead ground wire is selected in the middle of each segment ground wire

S2.21) Calculate the segmental pitch of the insulated overhead ground wire as 2*l ₀ ′=(16～30)*U ₀ /I(km), starting from one end of the insulated overhead ground wire at intervals of 2*l ₀ ′ Select the nearest tension tower as the segment node to segment the ground wire, and set the grounding point of the insulated overhead ground wire near the middle of each segment ground wire.

Method 2: Each segmented ground wire is grounded at a single point, and the entire insulated overhead ground wire is divided into several sections, and the insulation between each segment is disconnected, and each segment constitutes a segmented ground wire of the present invention.

The present invention has the following beneficial effects: 1) The present invention can reduce the induced voltage of the insulated overhead ground wire of the AC transmission line to an arbitrary setting of a lower level by calculating the transposition pitch or segmental pitch of the insulated overhead ground wire The induced voltage limit U ₀ , on the one hand, it is convenient to set the protection gap of the ground wire insulator according to the induced voltage limit U ₀ , which is beneficial to protect the ground wire insulator; on the other hand, the induced voltage of the insulating overhead ground wire is limited to a certain limit Within the value, it is helpful for the operation and maintenance personnel of the transmission line to form a clear understanding of the existence of the induced voltage of the insulating overhead ground wire, and it also provides a way to protect the personal and property safety of the workers on the live tower; The induced voltage of the ground wire is limited within the set induced voltage limit U ₀ , which is conducive to weakening the radio interference that may be caused by the insulated overhead ground wire;

2) Method 2 of the present invention can be applied to single-circuit and double-circuit AC transmission lines on the same tower, and has a wide range of applications; Method 1 and Method 2 of the present invention provide multiple wiring modes, The grounding method, the user can choose flexibly according to the actual situation, which has better practicability.

Description of drawings

Figures 1, 2, and 3 are structural schematic diagrams of three specific wiring methods of Method 1:

Figure 1 shows the transposition of the insulated overhead ground wire, where Figure 1a shows the situation where the ground point of the insulated overhead ground wire is at one end of the insulated overhead ground wire, and Figure 1b shows the situation where the ground point of the insulated overhead ground wire is between the two ends of the insulated overhead ground wire Condition;

Figure 2 shows the transposition of single-circuit transmission line conductors, where Figure 2a shows the situation where the grounding point of the insulated overhead ground wire is at one end of the insulating overhead ground wire, and Figure 2b shows that the grounding point of the insulated overhead ground wire is between the two ends of the insulated overhead ground wire Case;

Figure 3 shows the coordinated transposition of the insulated overhead ground wire and the single-circuit transmission conductor, where Figure 3a shows the situation where the grounding point of the insulated overhead ground wire is at one end of the insulated overhead ground wire, and Figure 3b shows that the grounding point of the insulated overhead ground wire is at the the situation between the two ends of the line;

Figure 4 is an embodiment of the specific wiring method of method two: among them, Figure 4a shows the situation where the grounding point of the insulated overhead ground wire is set at the end of each segment ground wire, and Figure 4b shows that the grounding point of the insulated overhead ground wire is set at the end of each segment The situation in the middle of the ground line.

Detailed ways

Below in conjunction with accompanying drawing, invention and four kinds of specific wiring modes thereof are further described: the transmission lines in Fig. 1-4 are all single-circuit AC transmission lines, and it is made of a pair of insulated overhead ground wires arranged in parallel and one three-phase Wire composition.

Fig. 1 is a schematic diagram of the structure of the specific wiring mode of the first method of the present invention - the transposition wiring mode of the insulated overhead ground wire. The wiring method of reducing the induced voltage through the transposition of the insulated overhead ground wire is suitable for single-circuit transmission lines with short lines and no transposition of the whole line. The insulated overhead ground wire is grounded at one point, and the grounding point can be selected as one end of the insulated overhead ground wire. Or between the two ends, as shown in Figure 1a and 1b respectively, the specific steps are as follows:

1-1) Determine the induced voltage limit U ₀ and the line current I of the insulated overhead ground wire;

1-2) Select the grounding point of the insulated overhead ground wire at one end of the insulated overhead ground wire or between the two ends of the insulated overhead ground wire:

1-2.1) If the grounding point of the insulated overhead ground wire is selected at one end

1-2.11) Calculate the transposition pitch of the insulated overhead ground wire as l ₀ = (8～15)*U ₀ /I(km), and select the nearest resistance point every l ₀ from the end of the insulated overhead ground wire The tension pole tower is used as the transposition node to perform the transposition of the ground wire, as shown in Figure 1a;

1-2.2) If the grounding point of the insulated overhead ground wire is selected to be between the two ends of the insulated overhead ground wire

1-2.21) Calculate the transposition pitch of the insulated overhead ground wire as 2*l ₀ = (16～30)*U ₀ /I(km), and select the nearest every 2*l ₀ from one end of the insulated overhead ground wire The tension pole tower is used as a transposition node for ground wire transposition, and the grounding point of the insulated overhead ground wire is set near half a transposition pitch from one of the transposition nodes, as shown in Figure 1b. Transposition node at half transposition pitch.

Fig. 2 is a schematic structural diagram of the specific wiring mode of the first method of the present invention - the transposition wiring mode of the single-circuit transmission line. The difference between it and the transposition wiring method of the insulated overhead ground wire is that, according to the selected position of the grounding point of the insulated overhead ground wire, the transposition of the operating wire is performed, and the whole line of the insulated overhead ground wire is not transposed. Specific steps to distinguish:

2-2.1) If the grounding point of the insulated overhead ground wire is selected at one end

2-2.11) Calculate the transposition pitch of the insulated overhead ground wire as l ₀ = (8～15)*U ₀ /I(km), and select the nearest resistance point every l ₀ from the end of the insulated overhead ground wire The tension tower is used as a transposition node to perform conductor transposition, as shown in Figure 2a;

2-2.2) If the grounding point of the insulated overhead ground wire is selected to be between the two ends of the insulated overhead ground wire

2-2.21) Calculate the transposition pitch of the insulated overhead ground wire as 2*l ₀ = (16～30)*U ₀ /I(km), and select the nearest every 2*l ₀ from one end of the insulated overhead ground wire The tension pole tower is used as the transposition node for wire transposition, and the grounding point of the insulated overhead ground wire is set near half a transposition pitch from one of the transposition nodes, as shown in Figure 2b. Half the transposition pitch of the bit node.

Fig. 3 is a schematic diagram of the structure of the specific wiring mode of the first method of the present invention-the insulated overhead ground wire and the single-circuit power transmission wire combined with the transposition wiring mode. The difference between it and the transposition wiring method of the insulated overhead ground wire is that according to the selected position of the grounding point of the insulated overhead ground wire, the wire transposition is operated at some transposition contacts, and the ground wire transposition is operated at the other part of the transposition contacts. Since the wire transposition and the ground wire transposition have the same effect of reducing the induced voltage of the insulated overhead ground wire, at each transposition node, the ground wire transposition or the conductor transposition can be selected according to the actual situation, as shown in Figure 3a and 3b .

Fig. 4 is a schematic structural diagram of a specific wiring mode of Method 2 of the present invention. The wiring method to reduce the induced voltage of the insulated overhead ground wire by segmenting the insulated overhead ground wire needs to be grounded at a single point for each segment of the insulated overhead ground wire. The grounding point can be selected as the end of the segmented ground wire or the middle of the segmented ground wire. The second invented method is applicable to single-circuit and double-circuit AC transmission lines on the same tower. Specific steps are as follows:

4-1) Determine the induced voltage limit U ₀ and the line current I of the insulated overhead ground wire;

4-2) Preliminarily choose whether the grounding point of the insulated overhead ground wire is set at the end of each segmented ground wire or in the middle of each segmented ground wire:

4-2.1) If the grounding point of the insulated overhead ground wire is selected at the end of each segment ground wire

4-2.11) Calculate the segmental pitch _of the insulated overhead ground wire as l ₀ ′=(8～15)*U ₀ /I(km), and select the nearest resistant The tension tower is used as a segmented node to segment the ground wire, and the grounding point of the insulated overhead ground wire is set at the same side end of each segmented ground wire, as shown in Figure 4a;

4-2.2) If the grounding point of the insulated overhead ground wire is selected in the middle of each segment ground wire

4-2.21) Calculate the segmental pitch of the insulated overhead ground wire as 2*l ₀ ′=(16～30)*U ₀ /I(km), starting from one end of the insulated overhead ground wire at intervals of 2*l ₀ ′ Select the nearest tension tower as the segment node to segment the ground wire, and set the grounding point of the insulated overhead ground wire near the middle of each segment ground wire, as shown in Figure 4b.

The present invention compares the measured value and simulated value of the induced voltage of the insulating overhead ground wire of some 500kV and 220kV AC transmission lines in the Guangdong area, calculates the induced voltage of the traditional insulating overhead ground wire and the induced voltage of the insulating overhead ground wire after using the method of the present invention, and compares As a result of both, the method of the present invention can not only effectively reduce the induced voltage of the isolated overhead ground wire of the AC transmission line, but also make the maximum value of the induced voltage of the isolated overhead ground wire lower than any limit value.

Claims (2)

1. reduce a method for transmission line of alternation current insulated static wire induced voltage, it is characterized in that, comprise the steps:

S1) insulated static wire induced voltage limit value U is determined ₀with line current I;

S2) select insulated static wire earth point in insulated static wire one end or be between insulated static wire two ends:

S2.1) if select insulated static wire earth point in one end

S2.11) calculating insulated static wire pitch of transposition is l ₀=(8 ~ 15) * U ₀/ I (km), every l from end described in insulated static wire ₀place selects strain rod tower nearby to carry out ground wire transposition or wire transposition as transposition node;

S2.2) if select insulated static wire earth point to be between insulated static wire two ends

S2.21) calculating insulated static wire pitch of transposition is 2*l ₀=(16 ~ 30) * U ₀/ I (km), every 2*l from insulated static wire one end ₀place selects strain rod tower nearby to carry out ground wire transposition or wire transposition as transposition node, and is located at by described insulated static wire earth point near one of them transposition node half pitch of transposition.

2. reduce a method for transmission line of alternation current insulated static wire induced voltage, it is characterized in that, comprise the steps:

S1) insulated static wire induced voltage limit value U is determined ₀with line current I;

S2) initial option insulated static wire earth point is located at each piecewise thread end and is also provided in the middle part of each segmentation ground wire:

S2.1) if select insulated static wire earth point at each piecewise thread end

S2.11) calculating insulated static wire segmentation pitch is l ₀'=(8 ~ 15) * U ₀/ I (km), every l from insulated static wire one end ₀' place selects strain rod tower nearby to carry out ground wire segmentation as segmented node, and insulated static wire earth point is located at each segmentation ground wire homonymy end;

S2.2) if select insulated static wire earth point in the middle part of each segmentation ground wire

S2.21) calculating insulated static wire segmentation pitch is 2*l ₀'=(16 ~ 30) * U ₀/ I (km), every 2*l from insulated static wire one end ₀' place selects strain rod tower nearby to carry out ground wire segmentation as segmented node, and insulated static wire earth point is located at each segmentation ground wire near middle.