CN201072678Y - Maintenance-free AC transmission line composite jacket metal oxide arrester - Google Patents

Abstract

The utility model relates to a metal oxide surge arrester with a composite jacket for maintenance-free AC transmission lines. The utility model belongs to a protection device for protecting electrical equipment or transmission line insulators of a 33-500KV AC system from overvoltage damage (or flashover) such as lightning and operation. The utility model is composed of a connecting terminal, a lightning arrester body, a disconnector, a supporting insulator, and a gap electrode, wherein the supporting insulator is connected to the lightning arrester body through a connecting fitting, and one end of the gap electrode is fixed on the bracket at the fixed end through a screw hole, and the disconnector at the other end is passed through The bolts are connected with the bracket and the gap electrodes, and the two ends of the lightning arrester are respectively fixed on the iron tower and the transmission wire through the connecting terminals. The utility model is connected in series and parallel with the insulators of the protected circuit, which can effectively improve the lightning resistance level of the circuit, reduce the tripping rate, and improve the reliability of power grid operation.

Description

Maintenance-free AC transmission line composite jacket metal oxide arrester

technical field

The utility model belongs to a protection device for protecting 33-500KV AC system electrical equipment or transmission line insulators from overvoltage damage (or flashover) such as lightning and operation. Specifically, it is a metal oxide surge arrester with a composite jacket for maintenance-free AC transmission lines.

Background technique

Before the utility model was proposed, in order to reduce lightning strike accidents of power lines and improve power supply reliability, someone proposed a method of installing lightning arresters on the line to reduce line lightning strike accidents. Since 1980, foreign countries have carried out research on the application of zinc oxide arresters for lightning protection of power systems, and have successfully applied arresters to transmission lines since then. However, the cost of traditional silicon carbide valve arresters is relatively high, and frequent maintenance and pre-testing are required, which brings great inconvenience to disassembly and assembly, which limits its large-scale application.

Contents of the invention

The utility model provides a metal oxide lightning arrester with a composite jacket with a smaller pressure ratio, larger flow capacity, higher reliability, and stronger pollution resistance, so that when the lightning arrester ages or is damaged by a fault, the separator Automatic action to separate the fault phase arrester from the system, achieving the purpose of maintenance-free operation.

Realize the technical scheme of the present utility model as:

The structure of this maintenance-free AC transmission line composite jacket metal oxide arrester (hereinafter referred to as the arrester) is composed of a connecting terminal, an arrester body, a disconnector, a supporting insulator, and a gap electrode. The supporting insulator is connected to the arrester body through a connecting fitting, and one end of the gap electrode It passes through the screw hole and is fixed on the bracket at the fixed end, and the disconnector at the other end is connected with the bracket and the gap electrode through bolts.

The working principle of the utility model is:

The arrester is made of metal oxide non-linear resistor as the main protection element. The arrester is connected in parallel with the protected equipment. When the system has an overvoltage that endangers the insulation of electrical equipment or transmission lines, the arrester is in a low-impedance conduction state, and the overvoltage is limited within the allowable value range, thereby protecting the insulation of electrical equipment from damage. , or avoid lightning flashover of transmission line (or catenary, etc.) insulators. Under normal operating voltage, the arrester is in a high-resistance insulation state, which insulates the system from the ground. The inside of the arrester is filled with special special arc-suppression materials, and has many technologies such as explosion-proof, detachment and maintenance-free.

The utility model is compared with the traditional silicon carbide valve arrester for operation comparison test to prove that:

The utility model has more excellent and reliable maintenance-free operation characteristics, and the lightning arrester connected in series and parallel with the insulator of the protected line can effectively improve the lightning resistance level of the line, reduce the tripping rate, and improve the reliability of the power grid operation.

In areas with strong lightning activities, after installing a set of arresters for 110kV transmission lines, if the impact grounding resistance R ₁ of lightning strikes the tower is not greater than 40Ω, the lightning withstand level of the line can be increased to above 65kA.

The 500kV line is installed with a set of arresters in areas with strong lightning activities. Even if the impact grounding resistance of the tower reaches 40Ω, the lightning resistance level can reach 350kA.

Description of drawings

Fig. 1 Schematic diagram of the structure of the utility model maintenance-free AC transmission line compound jacket metal oxide arrester

Fig. 2 schematic diagram of pure air gap maintenance-free arrester of the utility model

Fig. 3 The schematic diagram of maintenance-free surge arrester with insulating support series gap of the utility model

Figure 4 is a schematic diagram of the utility model without gaps, with a separator and maintenance-free arrester

In the drawings: connecting terminal 1, arrester body 2, disconnector 3, support insulator 4, gap electrode 5, voltage equalizing ring 6

Detailed ways

The utility model is specifically divided into three different types: pure air gap maintenance-free type (see attached drawing 2), series gap maintenance-free type with insulating support (see attached drawing 3) and no gap, maintenance-free type with separator ( See attached drawing 4).

The outer series gap line arrester has an optimally designed gap electrode, which has good field strength uniformity between electrodes, small discharge dispersion, and small lightning impulse discharge voltage deviation between positive and negative polarities. When atmospheric overvoltage occurs in the system, the air gap is accurate and reliable for discharge breakdown, and the arrester body then limits current and voltage. A flashover of the corresponding line insulator is thus reliably prevented. When the system is running normally, due to the isolation effect of the air gap, the arrester body hardly bears the system voltage - it is in a "rest" state, which effectively avoids the deterioration of the resistor sheet in the long-term system voltage, thereby improving the operational reliability.

No gap, surge arrester with separator, when the system has internal overvoltage such as atmospheric overvoltage and operation, the arrester presents low resistance, and the overvoltage is limited to a low level, which can avoid the overvoltage flashover of the corresponding line insulator, and can Limit the operating overvoltage to make the protection level more excellent. When the arrester ages or is damaged due to a fault, the separator will automatically operate (the arc is extinguished by means of the reclosing device for system protection under large freewheeling), so that the arrester of the fault phase is separated from the system.

The specific installation method is:

Maintenance-free type with insulating support series gap: The upper end of the arrester is directly hung on the installation frame on the iron tower, and the lower end of the outer series gap electrode of the arrester is connected to the high-voltage wire of the system through the drain wire. According to the actual installation position and space conditions of the tower, vertical and inclined installation methods can be selected.

Pure air gap maintenance-free type: the upper end of the arrester body is fixed to the installation frame of the iron tower with bolts, the upper electrode of the outer string gap is fixed to the lower end of the arrester, and the long axis of the elliptical upper electrode is perpendicular to the high-voltage wire; the lower electrode of the gap is fastened to the high-voltage wire Wire clamp, the axis of the lower electrode is parallel to the high-voltage wire. And pay attention to adjust the distance between the upper and lower electrodes to meet the specified requirements.

No gap, maintenance-free type with separator: the upper end of the arrester body is directly hung on the installation frame on the iron tower; The other end is connected with the high voltage wire.

Counters or monitors can be connected in series between the bottom plate of the arrester and the installation grounding plate, otherwise the bottom plate can be directly grounded.

Claims (1)

1. non-maintaining transmission line of alternation current polymeric metal oxide surge arrester is made up of splicing ear, lightning arrester body, disconnector, supporting insulator, clearance electrode, it is characterized in that: supporting insulator links to each other with lightning arrester body by connecting gold utensil, clearance electrode one end passes screw and is fixed on the stiff end support, other end disconnector links to each other with clearance electrode with support by bolt, and the whole two ends of lightning arrester are individually fixed on iron tower and the transmission pressure by splicing ear.

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