CN201118170Y - 20kV overhead insulated line overvoltage protector - Google Patents

Abstract

The utility model discloses a 20kV overhead insulated line overvoltage protector, which relates to a lightning protection device. The utility model comprises an insulated wire (1), an insulator (2), a current limiting element (3), a drain ring (4), a connecting fitting (5), a cross arm (6), a series gap (7); an insulator (2) Connect the current limiting element (3) through the connecting fitting (5) and fix it on the line cross arm (6), fix a diversion ring (4) horizontally on the top of the current limiting element (3), and center the insulator (2) Through the diversion ring (4), a certain series gap (7) is formed between the insulated wire (1) fixed on the insulator (2) and the diversion ring (4). The utility model has the advantages of simple structure, high cost performance, safety and reliability, and there is no need to strip the insulating layer of the overhead insulated wire (1) during installation, so it can be applied to lightning protection of 20kV overhead insulated wires.

Description

20kV overhead insulated line overvoltage protector

technical field

The utility model relates to a lightning protection device, in particular to an overvoltage protector for a 20kV overhead insulated line.

Background technique

Compared with the 10kV line, the transmission capacity and transmission distance of the 20kV distribution line can be doubled under the same conductor cross-section and passing current, and the power loss can be reduced by 50% under the same transmission power condition. Promote the application of 20kV overhead insulated lines.

However, overhead insulated lines are prone to lightning disconnection accidents, that is, when lightning overvoltage acts, the power frequency arc is concentrated at the breakdown point of the insulating layer, causing the insulated cable to burn and melt. At present, the lightning protection technology of 20kV voltage level overhead insulated lines is still blank in China, and a few lines temporarily use metal oxide arresters as line lightning protection devices. Metal oxide arresters can play a role in preventing lightning overvoltage, but it has the following disadvantages:

①The insulation layer of the insulated cable must be stripped during installation, causing rainwater to infiltrate along the stripped point of the insulation layer and corrode the metal wire of the insulated cable;

②The arrester not only bears the action of power frequency voltage for a long time, but also intermittently bears the action of lightning overvoltage and power frequency continuous flow, which is easy to age, has many faults, and is very expensive;

③ If the large lightning current passes through the arrester, the arrester cannot withstand it and is damaged, causing a short circuit to ground, resulting in disconnection of the insulated cable.

Contents of the invention

The purpose of the utility model is to overcome the above-mentioned shortcomings and deficiencies in the prior art, and provide a 20kV overhead insulated line overvoltage protector.

The purpose of this utility model is achieved in that:

It can be seen from Fig. 1 that the utility model includes an insulated wire (1), an insulator (2), a current limiting element (3), a drain ring (4), a connecting fitting (5), a cross arm (6), and a series gap (7) ;

The insulator (2) is connected with the current-limiting element (3) through the connecting fitting (5) and fixed on the line cross-arm (6), and a diversion ring (4) is horizontally fixed on the top of the current-limiting element (3), and the insulator (2) passing through the diversion ring (4) in the center, and forming a certain series gap (7) between the insulated wire (1) fixed on the insulator (2) and the diversion ring (4).

The working principle of the utility model is:

When a lightning overvoltage flashover occurs on the insulated wire (1), the high voltage of the lightning current first breaks through the series gap (7) between the insulation layer of the insulated wire (1) and the stainless steel diversion ring (4), leading the lightning current to The current limiting element (3), and flows into the ground through the current limiting element (3).

After the lightning current is released instantaneously, the voltage at both ends of the current limiting element (3) is the maximum power frequency overvoltage (i.e. the maximum operating voltage of the system) when the system does not generate an operating overvoltage at the same time, and the designed current limiting element (3) The rated voltage value is higher than the power frequency overvoltage value of the line, so the power frequency freewheeling current flowing through the current limiting element (3) is cut off, and the current limiting element (3) returns to a high resistance state in an instant, and is added to the series gap (7) The voltage value on the wire is reduced, which is not enough to maintain the arc, and finally the air insulation recovers quickly, so as to effectively prevent the overhead insulated wire (1) from being blown due to power frequency continuous flow and high temperature (lightning break).

The utility model has the following advantages and positive effects:

1. Through the synergistic effect of the series gap (7) and the current limiting element (3), it can effectively cut off the continuous current of power frequency, and avoid the disconnection accident of the insulated wire (1) after lightning strike;

2. It is not necessary to strip the insulation layer of the insulated wire (1) during installation, thereby eliminating the disadvantages of installing the arrester;

3. Due to the series gap (7), the current-limiting element (3) only works when there is a lightning current, and there is no continuous flow of power frequency, which improves the life of the utility model and is conducive to the safe operation of the power system;

4. Even if a large lightning current passes through the current-limiting element (3) and the current-limiting element (3) cannot withstand and is damaged, it is impossible to cause short-circuit grounding due to the isolation effect of the series gap (7), ensuring the safety of the power system.

In a word, because the utility model has simple structure, high cost performance, safety and reliability, and there is no need to strip the insulation layer of the overhead insulated wire (1) during installation, it can be widely used in lightning protection of 20kV overhead insulated lines.

Description of drawings

Fig. 1 is a structural diagram of the utility model;

Fig. 2 is a structural diagram of a circular drainage ring;

Fig. 3 is a structural diagram of a half-ring drainage ring;

Fig. 4 is a structural diagram of a linear drainage ring;

Fig. 5 is a structural diagram of a curved drainage ring;

Figure 6 is a schematic diagram of the installation of the utility model.

in:

1- insulated wire;

2 - insulator;

3-current limiting element;

4-drainage ring, 4.1-ring drainage ring, 4.2-semi-ring drainage ring,

4.3-straight line drainage ring, 4.4-curve drainage ring;

5-connection fittings;

6-cross arm;

7 - Tandem gap;

8- Electric pole.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

1. About the relevant components

1. Drainage ring (4)

Or a circular drainage ring (4.1), as shown in Figure 2;

Or a half-ring drainage ring (4.2), as shown in Figure 3;

Or a straight line drainage ring (4.3), as shown in Figure 4;

Or a curved drainage ring (4.4), as shown in Figure 5.

2. Tandem gap (7)

The series gap (7) is 100±5mm.

Two, about the installation of the utility model

As shown in Figure 6, the utility model is fixed on the pole (8) by the cross arm (6), and the insulated wire (1) is fixed on the insulator (2).

Claims (3)

1. A 20kV overhead insulated line overvoltage protector, characterized in that: Including insulated wires (1), insulators (2), current limiting elements (3), diversion rings (4), connecting fittings (5), cross arms (6), and series gaps (7); The insulator (2) is connected with the current-limiting element (3) through the connecting fitting (5) and fixed on the line cross-arm (6), and a diversion ring (4) is horizontally fixed on the top of the current-limiting element (3), and the insulator (2) passing through the diversion ring (4) in the center, and forming a certain series gap (7) between the insulated wire (1) fixed on the insulator (2) and the diversion ring (4). 2. A 20kV overhead insulated line overvoltage protector according to claim 1, characterized in that: The drainage ring (4) is either a circular drainage ring (4.1), or a half-ring drainage ring (4.2), or a straight line drainage ring (4.3), or a curved drainage ring (4.4). 3. An overhead insulated line overvoltage protector according to claim 1, characterized in that: The series gap (7) is 100±5mm.

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