CN105186372B - A kind of test method for being applied to research 10kV leakage conductor Contact patch - Google Patents

Abstract

A test method suitable for studying the grounding form of a 10kV line arrester, the method includes: building a test model of a 10kV power distribution line, the type of equipment selected should be consistent with the actual line, and the model layout includes 10kV concrete tower (1), iron cross-arm And hoop (2), 10kV line insulator (3), 10kV line outer series gap surge arrester (4), analog wire (5), grounding down conductor (6), impulse voltage generator (7), tower grounding resistance (8); The internal reinforcement of the concrete tower is always effectively grounded; the lightning impact comparison test is carried out under the conditions of laying the grounding downconductor separately and grounding through the grounding device, and not laying the grounding downconductor separately through the natural grounding of the tower. The invention studies how to adopt a reasonable grounding form for a line lightning arrester, so as to have a positive effect on the lightning protection of a power distribution line and provide guidance for actual engineering design.

Description

A test method suitable for studying the grounding form of 10kV line arrester

technical field

The invention relates to a test method suitable for studying the grounding form of a 10kV line lightning arrester, which belongs to the field of lightning protection of power distribution lines.

Background technique

The power distribution line is the level closer to the user in the power system. It is responsible for the important responsibility of supplying power to industrial and agricultural production and residents' daily life. It has the characteristics of complex line structure, large number of lines, and wide coverage area. In the past, the idea of focusing on the main network and ignoring the distribution network existed for a long time, resulting in a large gap between the equipment status and technical level of the current distribution network compared with the main network. The insulation level of distribution lines is low, and there are generally no special lightning protection measures. Not only are they affected by direct lightning strikes, but also insulator flashovers occur due to the influence of induced overvoltages generated by lightning strikes on the ground. Compared with high-voltage transmission lines, distribution lines are more prone to lightning flashover tripping, which seriously affects the reliability of power supply.

In view of the frequent lightning disasters of distribution lines, various lightning protection measures have been adopted at home and abroad, among which the installation of line arresters is a more effective way. The installation of line arresters plays a positive role in preventing direct lightning overvoltage and preventing induced lightning overvoltage.

In the actual project of 10kV distribution line, due to the consideration of economy and operability, the line arrester may not lay the grounding down-conductor separately, but use the steel bar inside the tower as the discharge channel. In the actual line, the concrete tower When a lightning flashover occurs on the line, it will break down the weak part of the cement insulation, and there is no systematic research and analysis on the impact on the lightning withstand level of the line, the protection effect of the arrester and the personal safety, and there is a lack of experimental verification.

Notification number CN203278165U discloses a 10kV power distribution overhead line lightning arrester layout structure, including cement towers, line lightning arresters, line insulators, power transmission wires, grounding down-conductors and tower grounding resistances, and the line lightning arresters and line insulators are connected and installed on the cement poles and towers , The high-voltage end of the line arrester is connected to the transmission wire, the ground end of the line arrester is connected to the grounding down conductor, and the grounding down conductor is connected to the grounding resistor of the tower through galvanized round steel or flat steel and then grounded. However, this utility model has the following problems: when the magnitude of the lightning current is large, a large voltage will be generated when it passes through the grounding resistance and enters the ground, which will cause the ground potential of the arrester to rise. This potential difference is added to the steel bars and cross arms inside the tower. At both ends of the insulation, the weak insulation of the cement tower will still be damaged, and the separate laying of the grounding downconductor will also increase the cost of line lightning protection.

Notification No. CN203160802U discloses a grounding integrated concrete pole adopting a fully built-in grounding electrode. A non-prestressed grounding steel bar is set in the body of the concrete pole as a built-in grounding downlead. At least one built-in grounding nut is provided in the middle and lower parts, one end of the built-in grounding nut is flush with the side surface of the concrete pole, or the side surface of the concrete pole is exposed, and the other end is fixed with the non-prestressed grounding steel bar; A grounding pipe support is set at the bottom of the pole, and the non-prestressed grounding steel bar is fixedly connected with the grounding pipe support; a grounding electrode is set under the grounding pipe support, and the grounding electrode and the grounding pipe support are fixed as a whole; the non-prestressed grounding steel bar , the grounding pipe bracket and the grounding electrode constitute the grounding electrode system of the concrete pole. This utility model saves costs, and due to the existence of the built-in grounding nut, it will not break down the weak insulation of the cement pole tower, but it has not been compared and studied through the system test whether the line arrester has a separate grounding down conductor to protect the general cement pole structure and arrester. The impact of the effect.

The notification number CN103015786 discloses a concrete pole with integrated grounding function. This utility model is similar to CN203160802U in features. By setting special non-prestressed grounding steel bars and grounding nuts, the concrete pole, grounding down conductor and grounding electrode The three-in-one connection becomes a whole, and the grounding steel bar is avoided from being exposed to the surface of the concrete pole.

In addition, most of the patents on lightning protection for 10kV distribution overhead lines do not mention how to systematically study the test method of the grounding lead form when the 10kV line arrester is installed on the concrete tower.

Contents of the invention

The purpose of the invention is, in order to study how to arrange the grounding form of the distribution line arrester when it is installed on the cement pole tower, thereby having a positive effect on the distribution line lightning protection, a kind of test method suitable for researching the grounding form of the 10kV line arrester is designed.

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

A kind of test method that is applicable to research 10kV line lightning arrester grounding form of the present invention comprises the following steps:

(1) Build a 10kV distribution line test model, the selected equipment type should be consistent with the actual line, the model layout includes 10kV cement pole tower, iron cross arm and hoop, 10kV line insulator, 10kV line with external series gap arrester, simulated wire, Grounding down conductors, impulse voltage generators, and tower grounding resistance; the internal steel bars of cement towers are always effectively grounded;

The aerial crane erects the concrete pole tower, and fixes the iron cross arm on the 10kV cement pole tower through the hoop;

The base of the 10kV line insulator is fixed on the iron cross arm, the simulated wire is bound to the upper end of the 10kV line insulator, and the outer series gap arrester for the 10kV line is installed in parallel on both sides of the 10kV line insulator according to the corresponding requirements;

The high-voltage lead wire of the impulse voltage generator is electrically connected to one end of the analog wire, and the steel bars inside the cement tower are effectively grounded through the tower grounding resistance;

One end of the grounding down-conductor is connected to the iron cross arm, and the other end is effectively grounded; a switch is set on the grounding down-conducting line;

(2) Lay a copper wire separately to ground the iron cross arm and the hoop, and electrically connect the high-voltage lead wire of the impulse voltage generator to one end of the analog wire, and use the negative polarity lightning wave with a waveform parameter of 1.2/50μs to carry out 30 lightning strikes according to the lifting method. Impact discharge test, record the test data and photos, and minimize the interference of external factors; then remove the hoop and observe whether there is any damage to the cement pole where the hoop is bound. If the trace is not obvious, you can wrap a layer of white on the hoop. Paper-assisted observation of test phenomena;

(3) Then restore the hoop, and remove the grounding down-conductor laid separately in step (2), and also use a negative polarity lightning wave with a waveform parameter of 1.2/50μs to gradually increase the voltage until the 10kV line uses an outer string gap When the lightning arrester discharges, record the test data and photos; keep the voltage constant, and after 30 lightning impulse discharge tests, observe whether there is any damage to the 10kV cement tower where the hoop is bound;

(4) Collate the test data, compare and analyze the influence of the 10kV line arrester with or without a separate grounding downconductor on the insulation strength of the 10kV cement tower and the protective effect of the outer series gap arrester for the 10kV line, and draw a reasonable conclusion.

The technical principle of the present invention is: in the existing actual engineering, due to the unreasonable grounding form of the lightning arrester, the phenomenon that the weak part of the cement insulation will sometimes be broken down when the lightning flashover occurs. The purpose of the invention is to study how to arrange the grounding form of the distribution line arrester installed on the concrete tower, so as to have a positive effect on the distribution line lightning protection. The lightning impulse discharge test is carried out under the condition that the grounding down-conductor is laid separately on the line arrester and the tower is naturally grounded, the breakdown voltage and breakdown trace of the weak insulation of the cement tower can be obtained, and the protection effect of the arrester can be observed, which is for the research The conclusion provides experimental data and verification.

The beneficial effect of the present invention is that, by building a test model of 10kV power distribution line, the present invention conducts lightning impact comparison tests under the conditions of separately laying the grounding down conductor and grounding through the grounding device and not separately laying the grounding down conductor through the tower. , we can study how to adopt a reasonable grounding form for line arresters, so as to have a positive effect on lightning protection of distribution lines and provide guidance for actual engineering design.

The invention can provide technical guidance and reference for lightning protection workers when studying the lightning protection design of 10kV power distribution lines.

Description of drawings

Fig. 1 is the structural representation of 10kV distribution circuit test model of the present invention;

In the figure, 1 is a 10kV cement tower; 2 is an iron cross arm and hoop; 3 is a 10kV line insulator; 4 is an external series gap arrester for a 10kV line; 5 is an analog wire; 6 is a grounding down conductor; 7 is an impulse voltage Generator; 8 is the tower grounding resistance.

detailed description

The specific embodiment of the present invention is shown in Fig. 1 .

The specific implementation steps are briefly described as follows:

(1) To build a 10kV distribution line test model, the selected equipment type should be consistent with the actual line, as shown in Figure 1, including 10kV cement tower 1, iron cross arm and hoop 2, 10kV line insulator 3, and 10kV line Outer string gap lightning arrester 4, analog wire 5, grounding down conductor 6, impulse voltage generator 7, tower grounding resistance 8.

Use the aerial crane to erect the 10kV cement tower 1, and fix the iron cross arm 2 on the 10kV cement tower 1 through the hoop;

Fix the base of the 10kV line insulator 3 on the iron cross arm 2, bind the simulated wire 5 to the upper end of the 10kV line insulator 3, and install the outer series gap arrester 4 for the 10kV line in parallel on both sides of the 10kV line insulator 3 according to the corresponding requirements;

The high-voltage lead wire of the impulse voltage generator 7 is electrically connected to one end of the analog wire 5, and the steel bar inside the 10kV cement tower is effectively grounded through the tower grounding resistor 8;

One end of the grounding down conductor 6 is connected to the iron cross arm 2, and one end is effectively grounded; a switch is arranged on the grounding down conductor.

(2) First lay a separate copper wire to ground the iron cross arm and the hoop, and electrically connect the high-voltage lead wire of the impulse voltage generator to one end of the analog wire, and use the negative polarity lightning wave with a waveform parameter of 1.2/50μs to carry out 30 times according to the lifting method Lightning impulse discharge test, record the test data and photos, and minimize the interference of external factors; then remove the hoop and observe whether there is any damage to the 10kV cement tower where the hoop is bound. If the trace is not obvious, you can wrap a piece of A layer of white paper assists in observing the test phenomenon.

(3) Then restore the hoop, cut off the grounding down-conductor laid separately in step (2) through the switch, and also use the negative polarity lightning wave with the waveform parameter of 1.2/50μs to gradually increase the voltage until the outer string gap for the 10kV line When the lightning arrester discharges, record the test data and photos; keep the voltage constant, and after 30 lightning impulse discharge tests, observe whether there is any damage to the 10kV cement tower where the hoop is bound.

(4) Organize the test data, compare and analyze the influence of the 10kV line arrester with or without a separate grounding downconductor on the insulation strength of the 10kV cement tower and the protection effect of the arrester, and draw a reasonable conclusion.

Claims (1)

1. a kind of test method that is applicable to research 10kV line lightning arrester grounding form, it is characterized in that, the steps of described method are as follows: (1) Build a 10kV distribution line test model, the selected equipment type should be consistent with the actual line, the model layout includes 10kV cement pole tower, iron cross arm and hoop, 10kV line insulator, 10kV line with external series gap arrester, simulated wire, Grounding down conductors, impulse voltage generators, and tower grounding resistance; the internal steel bars of cement towers are always effectively grounded; The aerial crane erects the concrete pole tower, and fixes the iron cross arm on the 10kV cement pole tower through the hoop; The base of the 10kV line insulator is fixed on the iron cross arm, the simulated wire is bound to the upper end of the 10kV line insulator, and the outer series gap arrester for the 10kV line is installed in parallel on both sides of the 10kV line insulator according to the corresponding requirements; The high-voltage lead wire of the impulse voltage generator is electrically connected to one end of the analog wire, and the steel bars inside the cement tower are effectively grounded through the tower grounding resistance; One end of the grounding down-conductor is connected to an iron crossarm, and the other end is effectively grounded; a switch is arranged on the grounding down-conducting line; (2) Separately lay a copper wire as the grounding down conductor to ground the iron crossarm and the hoop, the high voltage lead wire of the impulse voltage generator is electrically connected to one end of the analog wire, and the negative polarity lightning wave with a waveform parameter of 1.2/50μs is used to press the lifting Conduct 30 times of lightning shock discharge tests, record the test data and photos, and minimize the interference of external factors; then remove the hoop and observe whether there are any signs of damage to the cement tower where the hoop is bound. Wrap a layer of white paper to assist in observing the test phenomenon; (3) Restore the hoop, cut off the separately laid grounding down conductor through the switch, and also use the negative polarity lightning wave with the waveform parameter of 1.2/50μs to gradually increase the voltage until the 10kV line uses the outer series gap arrester to discharge, record Test data and photos; keep the voltage constant, and after 30 lightning impulse discharge tests, observe whether there is any damage to the 10kV cement tower where the hoop is bound; (4) Organize the test data, compare and analyze the influence of the 10kV line arrester with or without a separate grounding downconductor on the insulation strength of the 10kV cement tower and the protection effect of the outer series gap arrester for the 10kV line, and draw a reasonable conclusion.