JPH017941Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to improving the contamination withstand voltage of a multiple insulator device.

In power systems with a voltage class of 275KV or higher,
In order to reduce corona loss by reducing electric field strength and improve stability by reducing line reactance, the number of conductors per line is generally set to 2, 4, 6, 8, etc. depending on the voltage. A multi-conductor method is adopted. In this case, as the number of conductors increases, their weight also increases, so the mechanical strength required for the insulator chain that insulates and suspends them from the steel tower must also increase. Therefore, as shown in Figure 1, a high-strength insulator is used as the insulator 1, and at the same time, a plurality of single insulators are made by connecting the required number of insulators to obtain the required insulation distance according to the system voltage. A so-called multiple insulator device is used in which a plurality of insulators 1 are assembled together using upper and lower fasteners 3 and 4 so that each component insulator 1 is aligned on the same line L and is spaced apart from each other by l.

By the way, it is generally well known that the withstand voltage of an insulator decreases when an insulator becomes dirty or wet, for example, when it becomes dirty or wet due to salt damage. Particularly in the case of a conventional multiple insulator device as shown in FIG. An arc that occurs locally in one insulator strand becomes intertwined with other adjacent insulator strands, generating an arc in the low resistance part, which further spreads to other adjacent insulator strands, resulting in contamination. The withstand voltage is lower than that of a single insulator device with the same connection length. Figure 2 shows an example of the measurement results for a 54-ton high-strength suspension insulator (shade diameter 380 mm, leakage distance 670 mm).
645 mm)
These are the results of measuring the equivalent 5% flashover voltage in fog while changing the conductivity of the soiling liquid (salt) for two and four hanging systems with an interval l (see Figure 1).

As is clear from this, regardless of the amount of contamination, the flashover voltage decreases by about 5% compared to single station A in the case of 2-station B, and about 10% compared to single station A in the case of 4-station C. . Also, according to calculations, the contamination withstand voltage decreases in proportion to the increase in the number of stations. Therefore, for example, ultra-high voltage power transmission, which is currently being researched with the aim of efficient power transmission by further reducing power transmission losses, is
When it is unavoidable to increase the number of insulators due to the inevitable increase in the number of conductors per unit, such as in 1000KV power transmission, countermeasures are necessary, and the following methods may be considered, for example. One method is to increase the withstand voltage by increasing the number of connected insulators per series, and the other method is to increase the distance between the insulators to prevent local arcs between adjacent series. This is a way to prevent entanglement. However, an increase in the number of insulator connections will result in higher construction costs for the power transmission system, even if only the lines along the coastline, which are susceptible to salt damage, do not cover the entire line. Furthermore, in order to prevent the contamination withstand voltage from decreasing to a satisfactory extent by increasing the interval, the interval must be made considerably wider. This creates new difficulties, such as requiring major changes to the structure of the steel tower, making it extremely difficult to realize.

The present invention aims to provide a multi-row insulator device which can have almost the same stain resistance voltage characteristics as a conventional single-row insulator device with the same number of connected insulators, regardless of the number of rows, under the same series spacing. This was developed for this purpose, and the details will be explained below using the drawings.

Decrease in the contamination withstand voltage in multiple insulator equipment
Conditions not seen in single insulator devices, i.e. 1
As mentioned above, a local arc generated in a particular insulator strand generates a new local arc by intertwining with other adjacent insulator strands, and this successively spreads to other adjacent insulator strands. .

The present inventor believes that the decrease in the contamination withstand voltage characteristics of conventional multiple insulator devices compared to single insulator devices is due to changes in electric field distribution due to the combination of multiple single insulators, which makes local arcs more likely to occur. From this viewpoint, we repeated experiments on a combination structure using upper and lower hanging metal fittings of a single insulator device.
As a result, as in the conventional multiple insulator device described above with reference to FIG.
By arranging the single insulators 2 constituting the multiple insulator device so as to alternately shift them in the vertical direction instead of arranging them adjacent to each other in the same position, the contamination withstand voltage characteristics can be improved. It was made clear that it would be possible.

The present invention was developed based on the above research results, and its characteristics are as shown in FIG. As shown by the dotted lines in the figure, the porcelain parts 1a are located between the constituent insulators 1, that is, the porcelain parts 1a correspond to the connecting fittings 1b of the adjacent insulators 1, so that they are arranged in a staggered manner. It is.

Figure 4 shows the above experimental results. A 54-ton high-strength insulator (shade diameter 380 mm, leakage distance 670 mm) was
A single series insulator device A constructed by connecting multiple series insulators, a multiple series insulator device B of the present invention constructed by suspending four series insulators at intervals of 645 mm so as to form a staggered pattern, and the same single series insulator device A. 5% in the equivalent fog while changing the salt adhesion density for the multiple insulator device C, which is configured by hanging four insulators with the same spacing and arrangement as before.
This is the result of determining the flashover voltage.

As is clear from this, the contamination withstand voltage characteristics of the inventive multiple insulator device B, as shown by the solid line curve in the figure, are improved compared to those of the conventional multiple insulator device C, shown by the dotted line curve in the figure. However, regardless of the salt adhesion density, the contamination withstand voltage characteristics match those of the single insulator device A. Therefore, as shown in Figure 3, by only increasing the length in the chain direction by approximately half the length of the insulator, the number of connected insulators per series and the spacing between each series remain exactly the same as before. , it is possible to provide a multi-row insulator device that has the same contamination withstand voltage characteristics as a single-row insulator device, and does not increase the construction cost of the power transmission line, unlike conventional methods for improving the contamination withstand voltage characteristics.

In addition, when creating a staggered shape in which each insulator constituting a series is inserted between each insulator of an adjacent series as described above, strictly speaking, the contamination withstand voltage depends on the shape of the insulators, especially the shape of the porcelain part. Therefore, it may be necessary to adjust the vertical position of the adjacent insulators 1 between the insulators 1. Furthermore, although the explanation has been given above for use in suspension, it goes without saying that it can also be applied to use in tension. In addition, as in the present invention, a third type of insulator is used for hanging single-strand insulators at different positions alternately in the chain direction.
The upper and lower hanging fittings 3 and 4 shown in the figure have a slightly different shape and are slightly more expensive than those of the conventional multiple insulator device, but this is hardly a problem with respect to the price of the entire insulator device.

As is clear from the above explanation, a multi-row insulator device with a contamination withstand voltage characteristic equivalent to that of a single-row insulator device can be achieved by simply arranging adjacent single-row insulators at different positions in the row direction. The practical effects are great.

[Brief explanation of the drawing]

Figure 1 shows a conventional multiple insulator device, Figure 2
The figure shows the contamination withstand voltage characteristics of a single insulator device and a conventional multiple insulator device, Figure 3 is an example of the multiple insulator device of the present invention, and Figure 4 shows a single insulator device and a multiple insulator device of the present invention. FIG. 3 is a diagram showing the contamination withstand voltage characteristics of the device. 1...Insulator, 1a...The porcelain part, 1b...Connection fittings, 2...Single insulator.

Claims (1)

[Scope of utility model registration request] A multiple series insulator device, characterized in that each single series insulator forming the multiple series insulator device is arranged with its position shifted in the series direction so as to form a staggered arrangement between adjacent single series insulators.