JPH0318953Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention consists of continuously welding a tube filled with an insulating gas, and storing a high-voltage conductor with insulated support inside the tube. The present invention relates to busbars, and particularly to gas-insulated busbars that can detect ground fault points in the event of a ground fault.

[Technical background of the invention and its problems]

In recent years, instead of using power cables to connect each yard in a substation, gas-insulated busbars, which house insulated and supported high-voltage conductors in pipes and fill them with insulating gas such as SF ₆ gas, have begun to be used. I'm getting used to it. If a ground fault occurs in this gas-insulated bus, the internal high-voltage conductor and inner surface of the tube will melt, so the part where the fault occurred must be replaced. but,
Since there were no changes to the outside surface of the tube, it was necessary to completely disassemble it and make internal adjustments in order to find the ground fault point, that is, the part that needed to be replaced over several hundred meters of busbar. For this reason, once a ground fault occurs, it takes a long time to recover, and the power transmission line becomes weakened during that time.

[Purpose of invention]

This invention was made taking the above points into consideration.
The purpose of this is to provide a gas that can easily detect ground fault points from outside the pipe and shorten the period of recovery work after a ground fault in pipes formed by sequentially welding and connecting multiple pipes. The purpose is to provide an insulated busbar.

[Summary of the idea]

In order to achieve this purpose, the present invention involves welding and connecting pipes to form a continuous pipe, in which a high voltage conductor is housed with insulated support, and a length of approximately 20 m or less in the longitudinal direction is attached to the outer circumferential surface of the continuous pipe. By arranging ground fault point detectors equipped with acceleration sensors at different intervals, it is possible to easily detect ground fault points from outside the pipe and shorten the recovery work period after a ground fault. Features.

[Example of idea]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A gas insulated bus bar according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the gas insulated bus bar is constructed by sequentially welding a plurality of tubes to form a continuous tube 11. Inside this continuous tube 11, an insulated and supported high voltage conductor 12 shown by a dotted line is housed _. It is formed by filling an insulating gas such as gas. By the way, due to this official transport restriction, a length of approximately 10m is used. The gas insulated bus bar thus formed is installed on a foundation (not shown) with legs 15 provided every 20 m, for example.

And ground fault detectors 16 _-1 , 1 each having an acceleration sensor approximately at the center between adjacent legs 15
6 _-2 shall be established. In other words, ground fault detectors will be installed every 20m. The distance between the legs 15 is approximately 20 m, and the position where the ground fault detector 16 _-1 in the center is installed is point A, the position where the ground fault detector 16 _-2 is installed is point B, and the point A The position of the leg 15 between point B and point C
Point. Therefore, the distance between points A and C is 10 m, and the distance between points C and B is 10 m.

Although not shown, the ground fault detector 16 is configured to provide a meter display that maintains the peak through an acceleration sensor such as a pickup and a measurement circuit, and the acceleration sensor is attached closely to the outside of the continuous pipe 11.

The ground fault is between the high voltage conductor 12 and the continuous pipe 1 shown by the dotted line.
A flashover, that is, a ground fault current flows between the pipe wall of No. 1 and the pipe wall of No. 1. This ground fault current impacts the pipe wall. The vibrations generated in the tube by this impact have an acceleration of several hundred G and a frequency band of 500Hz to 5kHz, and these vibrations propagate along the tube while being attenuated.

Since the ground fault detector 16 utilizes the above-mentioned phenomenon, the acceleration sensor has the characteristics of sensing an acceleration of 100G to 700G and a frequency band of 500Hz to 5kHz. The vibration caused when a stone or tool hits a pipe is similar to the vibration caused by a ground fault, but in this case the acceleration is about 50G to 70G, and the vibration caused by a ground fault is caused by a vibration that occurs in the longitudinal direction from the point of the ground fault.
Attenuation is 5% per meter and 8% per leg.

Next, the effects of the gas insulated bus bar of the present invention will be explained. A ground fault detector 16 is provided every 20 m in the longitudinal direction of the continuous pipe 11. That is, for example, if the interval between adjacent legs 15 is 20 m, a ground fault detector 16 is installed approximately in the center of each continuous pipe 11 having a length of 20 m.
, the distance between the ground fault detectors 16 _-1 and 16 _-2 will be 20 m, and the distance between the ground fault detectors 16 -1 and 16 -2 will be 20 m.
_-1 , 16 _-2 are placed at point A and point B, respectively.
The leg portion 15 is located in the center between points A and B, and this position is defined as point C. Therefore, point A and B
The distance between points is 20m, and the distance between points A and C and between points B and C is 10m.

For example, suppose that a ground fault occurs at any position on the gas-insulated bus between points A and B, and the ground fault at point A is the ground fault 20a, the point B is the ground fault 20b, and the ground fault 20 is the ground fault at the point C.
Let it be 0c. However, this is to state that the ground fault does not travel between points A and B, but rather captures the impact when a ground fault occurs at an arbitrary point.

When a ground fault occurs in this way, the ground fault detector 16 _-1 placed at point A and the ground fault detector 16 _-2 placed at point B detect the acceleration of vibration caused by this ground fault. The characteristics are shown in FIG. 2. In FIG. 2, the vertical axis represents acceleration G, and the horizontal axis represents the distance (m) from point A to point C and point B, with point A as zero. The characteristics indicate the relationship between the acceleration detected by the ground fault detector _16-1 and the ground fault position, and the characteristics indicate the relationship between the acceleration detected by the ground fault detector _16-2 and the ground fault position. There is.

As shown in the characteristic diagram, when a ground fault 20a occurs at point A, the acceleration detected by the ground fault detector _16-1 is 150G, and when the ground fault position changes to the right in the figure, the pipe vibrates. is attenuated and tilts to the right, and when ground fault 20b occurs at point B at the right end, approximately 32G is detected.

Also, as shown in the characteristics, when the ground fault 20b occurs at point B, the acceleration detected by the ground fault detector _16-2 is 150G, and when the ground fault position changes to the left in the figure, the pipe vibrates. is attenuated and becomes downward to the left, and when there is a ground fault 20a at the leftmost point A, it is almost
Detect 32G.

If the intersection of both characteristics 1 is the intersection point P, this point corresponds to the leg 15, that is, point C, and both characteristics,
is bent attenuated by the leg portions 15. This intersection point P indicates approximately 85G. That is, when there is a ground fault 20c at point C of the gas insulated bus, both ground fault point detectors 16 _-1 and 16 _-2 simultaneously detect acceleration values. Intersection P is both ground fault detector 16
_-1 , 16 _-2 when the interval is 20 m,
As mentioned above, the acceleration when a stone or tool collides with the pipe is 70G or 50G, which is well above the noise level of 70G shown by the two-dot chain line, so it can be detected separately.

Therefore, the distance between the ground fault detectors should be set at 20m.
If the distance between them is shortened, the attenuation due to the pipes will be reduced, so the intersection point P will be located higher than shown in the figure. That is, since both characteristics have a gentler slope, the intersection point P is far above the noise level, and therefore it is extremely easy to distinguish it from noise. Conversely, if the distance between ground fault detectors is set to 20 m or more, the slope of the characteristic becomes steeper than shown. In other words, since the intersection point P moves close to or below the noise level, for example, a ground fault that occurs near the middle of both ground fault point detectors 16 _-1 and 16 _-2 is difficult to distinguish from the noise level. Or it becomes completely unrecognizable. For this reason, it is necessary to set the interval between the ground fault point detectors to 20 m or less, and it is preferable to set the interval to about 20 m.

Furthermore, if the detectors are installed at intervals approximately equal to the length of each tube forming a continuous tube, one detector will be provided for each tube, which is economical. Although it is possible to install two or more pipes in one pipe, it is economically possible to use up to two pipes.

In this manner, when a ground fault occurs, the position of the ground fault point can be detected from the characteristic of the ground fault point detector that detects the largest acceleration. Further, when adjacent ground fault point detectors detect substantially the same value, it is possible to detect that a ground fault has occurred at the center of both. Since the position of the ground fault point can be easily detected from the outside of the gas-insulated bus bar in this way, the period of restoration work from a ground fault accident can be significantly shortened.

[Effect of idea]

As explained above, according to the gas insulated busbar of the present invention, a plurality of ground fault point detectors are installed along the longitudinal direction on the outside of a continuous tube formed by joining a plurality of tubes.
By arranging them at equal intervals of 20 m or less, the ground fault point can be easily detected from outside the pipe in the event of a ground fault accident, and the recovery work period can be significantly shortened.

[Brief explanation of the drawing]

Figure 1 is a side view of the gas insulated bus bar of the present invention, Figure 2
The figure is a diagram showing the detection characteristics of the ground fault point detector in the event of a ground fault accident on the gas-insulated busbar shown in FIG. 1. 11... Continuous pipe, 12... High voltage conductor, 15...
... Legs, 16 _-1 , 16 _-2 ... Ground fault detector, 20
a, 20b, 20c...ground fault.

Claims (1)

[Scope of utility model registration request] A high-voltage conductor is insulated and supported inside a continuous pipe made by welding and joining pipes, and an insulating gas is filled in. The outer circumferential surface of the continuous pipe is approximately equally spaced with a longitudinal length of about 20 m or less. A gas insulated bus bar characterized in that a plurality of ground fault point detectors each having an acceleration sensor are arranged so as to have the following characteristics.