CN105655962A - Novel lightning protection device of overhead distribution line - Google Patents

Abstract

The invention relates to a new type of lightning protection device for overhead power distribution lines, which includes an overhead power line, a terminal pole, and a high-voltage lightning protector. The terminal pole is installed on the ground above the grounding grid and the terminal pole is arranged outside the building and its power equipment. The top of the terminal pole is connected to an overhead power line and the overhead power line is connected to a high-voltage lightning arrester; the high-voltage lightning arrester has a number of lightning arresting insulators inside, and the number of lightning arresting insulators is 1, 3 or at least 3; The interior of the high-voltage surge arrester is connected in parallel. The beneficial effect of the novel lightning protection device for overhead distribution lines of the present invention is that by adding a line post-type variable-ratio clamp lightning protection insulator, it is beneficial to special grounding down conductors, and will not affect power transmission due to its own faults. There are fault indications for easy inspection, exactly the same size and structural characteristics as the existing insulators, allowing lightning current to pass through, blocking power frequency freewheeling, and high operational reliability.

Description

A new type of lightning protection device for overhead distribution lines

technical field

The invention relates to lightning protection technology for overhead power distribution lines, in particular to a novel lightning protection device for overhead power distribution lines.

Background technique

Aiming at the problem of frequent lightning disconnection accidents on overhead distribution lines, the preventive measures are discussed in order to improve the safe operation level of distribution networks. At present, insulated wires have been widely used on overhead distribution lines, but some new problems have appeared in the application process of insulated wires; among them, the most prominent problem is that they are prone to disconnection when struck by lightning Accidents: According to relevant statistics, within two years from 2008 to 2009 in Nanchang Economic and Technological Development Zone, within a 30-square-kilometer power supply area, there were about 35 lightning disconnection accidents and lightning tripping accidents, and the direct power loss was about 300,000 kwh , seriously reduced the reliability of power supply, and brought adverse effects to the society. In the past two years, the accident rate of lightning strike disconnection accounted for 76.2%. Some of the above statistical data show that the lightning strike disconnection accident is the most prominent serious problem in the application of insulated wires. This has attracted our extensive attention, and we have actively carried out peer-to-peer experimental research and found many effective preventive measures.

The main causes of lightning disconnection accidents are as follows: ①Lightning overvoltage flashover of the power grid, that is, large current discharge in atmospheric pressure or higher than atmospheric pressure, which is in the form of arc discharge; ②When lightning overvoltage flashover occurs, the instantaneous arc current is very large, but The time is very short; ③When the lightning overvoltage flashover, especially between two phases or three phases, a metallic short-circuit channel is formed, causing thousands of amperes of continuous current, and the arc energy will increase suddenly.

When the lightning strikes the overhead insulated line to generate a huge lightning overvoltage, when it exceeds the withstand voltage level of the wire insulation layer, it will find the weakest point of the electric field along the wire to break down the insulation layer of the wire (usually within 30 cm at both ends of the insulator), A pinhole-sized breakdown point is formed, and then the insulator is discharged along the surface to form a flashover. Finally, the power-frequency arc develops to the metal at the root of the insulator and forms a metallic short-circuit channel. The power-frequency arc is fixed at one point and burns to fuse the wire; When a huge lightning overvoltage occurs on the wire, the insulator along the wire looking for the weakest point in the electric field will discharge along the surface to form a flashover. Finally, the power frequency arc develops to the metal at the root of the insulator and forms a metallic short circuit channel, causing a line tripping accident.

What needs to be pointed out here is that according to conventional principles, several aspects of analysis are required:

The protection principle and protection range of lightning insulators, that is, to carry out theoretical calculations and verification tests, determine the proportional parameters of voltage clamping; The difference; the combination and structure of the arrester and insulator, through the verification test, confirm the difference between the nonlinear clamping element installed on the high voltage side and the grounding side; according to the destruction principle of the nonlinear clamping element, develop a new type of thermally sensitive explosive element, It acts when the nonlinear clamping element is damaged, and has an obvious sign, which can easily find the fault point; study the thermal expansion coefficient of different materials, and make it possible to compensate each other under harsh natural conditions; study lightning protection The optimal sealing structure and sealing method of insulators; study the difference between different fixing methods of insulated wires and bare wires on lightning insulators; the law of man-made weak points on insulated wires and the natural breakdown point of lightning; lightning activity paths in different installation methods of lightning insulators The impact of different grounding methods and different grounding resistances on the overvoltage protection performance of lightning insulators.

The lightning protection insulator is a new concept lightning protection device for distribution lines. It combines lightning arresters and insulators into one, which conforms to the general trend of lightning protection for international distribution lines. For this reason, we combine the above problems, and can be widely used in the lightning protection of overhead insulated conductors and bare conductor lines of power systems with voltage levels of 35kV and below, and can also be used to protect distribution transformers. Therefore, in view of the above aspects, it is necessary to effectively innovate the prior art.

Contents of the invention

In view of the above defects, the present invention provides an insulator that will not affect power transmission due to its own faults, has fault indications for easy inspection, is exactly the same size and structural characteristics as existing insulators, allows lightning current to pass through, blocks power frequency freewheeling, and operates reliably. A new type of lightning protection device for overhead distribution lines with high reliability to solve many deficiencies in the existing technology.

To achieve the above object, the present invention adopts the following technical solutions:

A new type of lightning protection device for overhead power distribution lines, including overhead power lines, terminal poles, and high-voltage lightning protection devices. The terminal pole is installed on the ground above the grounding grid and the terminal pole is arranged outside the building and its power equipment. The terminal The top of the pole is connected to an overhead power line and the overhead power line is connected to a high-voltage lightning arrester;

There are several lightning insulators inside the high-voltage lightning arrester, the number of which is 1, 3 or at least 3; the lightning insulators are connected in parallel inside the high-voltage lightning arrester.

An iron tower is added around the building and its power equipment, and a lightning receptor is installed on the top of the iron tower, and an antenna is provided on the iron tower.

The lightning insulator is a line column variable ratio clamp type, and a zinc oxide arrester is installed on the ground wire at the bottom of the terminal pole.

The beneficial effects of the novel lightning protection device for overhead distribution lines of the present invention are:

(1) By adding a line post-type variable ratio clamp lightning protection insulator, it is beneficial to the special grounding down-conductor, will not affect the power transmission due to its own fault, and the fault indication is convenient for inspection, and it is completely consistent with the size and structural characteristics of the existing insulators. The same, allowing lightning current to pass through, blocking power frequency freewheeling, and high operational reliability;

(2) It can eliminate the four major problems caused by lightning damage, so that lightning does not trip, insulation does not break down, lines do not burn out, and wires are not disconnected, ensuring safe and reliable power supply, providing intelligent and uninterrupted power supply for distribution lines. F;

(3) Reduce the annual pre-test, facilitate the discovery of fault points, and reduce the time to find faults and power outages;

(4) Through expansion and reconfiguration, live work can be carried out, and lightning protection insulators can be removed and installed. There is an additional lightning protection device for distribution lines, and it is on the side of the insulator. Because there is a potential difference with the insulator, most of them can be charged but not installed. Live dismantling and lightning protection insulators are designed as a whole because of the integrated structure, there is no potential difference, and they can be disassembled when live, reducing power outage time, increasing electricity sales, and adapting to the trend of live work;

(5) The lightning protection insulator is self-clamping and self-protecting, and does not require a special grounding down-conductor. Compared with the existing lightning protection mode, the installation of the insulator with additional lightning protection devices and grounding devices is simple, fast, and highly reliable. Total cost dropped by 1/2 strong.

Description of drawings

The present invention will be described in further detail below according to the accompanying drawings.

Fig. 1 is a structural schematic diagram of a novel lightning protection device for an overhead power distribution line according to an embodiment of the present invention;

Fig. 2 is a partial circuit schematic diagram of the novel lightning protection device for overhead distribution lines according to the embodiment of the present invention.

In the picture:

1. Overhead power lines; 2. Terminal rods; 3. Lightning insulators; 4. High-voltage lightning arresters; 5. Zinc oxide arresters; 6. Buildings and their electrical equipment; 7. Iron towers; 8. Antennas; 10. Lightning receptors.

detailed description

As shown in Figures 1-2, the new lightning protection device for overhead distribution lines described in the embodiment of the present invention includes an overhead power line 1, a terminal pole 2, and a high-voltage lightning protector 4, and the terminal pole 2 is installed above the grounding grid 9 and the terminal pole 2 is arranged outside the building and its power equipment 6, and at the same time, an iron tower 7 is added on the periphery of the building and its power equipment 6;

Correspondingly, the top of the terminal pole 2 is connected to the overhead power line 1 and the overhead power line 1 is connected to the high-voltage lightning arrester 4. It is a line column type variable ratio clamping type and its quantity can be 1, 3 or at least 3. The lightning insulator 3 is connected in parallel inside the high voltage lightning arrester 4; the lightning insulator 3 is self-clamping, self-clamping Compared with the existing lightning protection mode, the additional lightning protection device and grounding device for the insulator are simple, fast and reliable to install, and the total cost is reduced by 1/2.

Correspondingly, a zinc oxide lightning arrester 5 is installed on the ground wire at the bottom of the terminal pole 2 , a lightning receptor 10 is installed at the top of the iron tower 7 , and an antenna 8 is installed on the iron tower 7 .

The above-mentioned description of the embodiments is for those of ordinary skill in the technical field to be able to understand and apply the technology of this case. Those skilled in the art can easily make various modifications to these examples. Therefore, this case is not limited to the above embodiments. Based on the disclosure of this case, those skilled in the art should make improvements and modifications to this case within the scope of protection of this case.

Claims (4)

1. the novel lightning protection device of overhead distribution, comprise overhead power transmission line (1), end pole (2), high pressure lightning protection device (4), end pole (2) is arranged on the ground of ground net (9) top and this end pole (2) is arranged at buildings and power equipment (6) is outside, it is characterised in that:

Described end pole (2) top connects overhead power transmission line (1) and this overhead power transmission line (1) upper connection high pressure lightning protection device (4);

This high pressure lightning protection device (4) is inner with some lightning protection insulators (3), and this lightning protection insulator (3) quantity is 1,3 or at least 3;

This lightning protection insulator (3) is inner at high pressure lightning protection device (4) is parallel way connection.

2. the novel lightning protection device of overhead distribution according to claim 1, it is characterized in that: steel tower (7) is set up in described buildings and power equipment (6) periphery thereof, described steel tower (7) top is installed to connect and is dodged device (10), with antenna (8) on steel tower (7).

3. the novel lightning protection device of overhead distribution according to claim 1, it is characterised in that: described lightning protection insulator (3) is line pole type variable ratio clamper type.

4. the novel lightning protection device of overhead distribution according to claim 1, it is characterised in that: Zinc-Oxide Arrester (5) installed by the ground electric wire of described end pole (2) bottom.