JPH0155568B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to high voltage electrical equipment.

High-voltage (including ultra-high voltage) electrical equipment, such as a collective capacitor device, surrounds the assembled capacitor body (electrical equipment main body) with an internal shield, and the outer periphery is further covered with an insulator for ground insulation. surround. For example, as shown in FIG. 1, the internal shield S is formed by framing a metal pipe P in a box shape, and closing each tube with a metal flat plate M to form the box shape. The reason why the pipe P is used here is that by forming each edge into an arc shape, the potential gradient can be made lower than by forming each edge into an angular shape. Then, at the corner edge (the part where the three planes intersect), a delta corner D made of an insulator (for example, pipe molded) is formed so that the three planes are perpendicular to each other, and at the edge corner ( By applying a corner L made of an L-shaped insulator (for example, made of pressboard) to the area where two planes intersect, and by applying a flat insulator to each plane. Enclose and provide ground insulation. Note that R is a hole for leading out the lead.

However, as understood from the above explanation, such a delta corner D intersects three planes that are perpendicular to each other, and each intersection must be arcuate to match the radius of curvature of the pipe P. It is extremely troublesome to produce a shape that satisfies these conditions. If the perpendicularity of each plane is out of order or does not match the radius of curvature of the pipe P, if this is applied to the corner edge, the distance between it and the outer surface of the inner shield is shown in Figure 5. A gap G is likely to occur as shown in FIG. Therefore, when this is immersed in insulating oil, an oil layer will be formed in the gap G. Furthermore, the radius of curvature at the corner portion of the internal shield is determined by the radius of curvature of the pipe that forms the frame of the internal shield, and it cannot be made too large. For these reasons, there are drawbacks such as a large potential gradient at the corner portion and a low partial discharge inception voltage.

In order to increase the radius of curvature at the corner of the internal shield, it is possible to use a pipe P with a large radius, that is, a thick pipe. However, if such a pipe is used, the entire device becomes larger and the capacitor element is In order to insert the element body later, it is necessary to provide a space equal to the diameter of the pipe P between the outer surface of the body and the inner surface of the inner shield, and the dead space increases accordingly.

This invention improves partial discharge characteristics by reducing the potential gradient at the corner portions of the inner shield without increasing the radius of curvature at the corner portions, and by preventing the formation of an oil layer that is a weak point in insulation characteristics. With the goal.

This invention prepares a delta corner electrode in which a conductive layer is provided on the inner surface of an insulating molded article having a large radius of curvature and which has substantially the same shape as a delta corner, and interposes this between the innermost delta corner and an internal shield, and the conductive layer and the internal shield are connected with a conductive wire so that they have the same potential.

The insulating molded product constituting the delta corner electrode is preferably pipe-molded, for example, and in order to provide a conductive layer thereon, the electrode plate may be integrally molded or formed by applying a conductive paint. It's okay.

Embodiments of the present invention will be described with reference to FIG. 2 and subsequent figures. DM is a delta corner electrode according to the present invention, which, like the delta corner D, includes an insulating molded object DC having three planes at right angles to each other;
It is composed of a conductive layer E provided on its inner surface. The edges where the planes intersect have a radius of curvature larger than the radius of curvature of the corner portion of the inner shield, that is, the radius of curvature of the pipe P.

As shown in FIG. 2, the delta corner electrode DM is placed so that its inner surface is in close contact with the corner edge of the inner shield S. and conductive layer E and inner shield S
and is connected by a conductive wire W, and the potential of the conductive layer E is fixed to the potential of the inner shield S. delta corner electrode
Overlap delta corner D on the outer circumference of DM. The delta corner D used here is constructed to be somewhat longer than the delta corner electrode DM. Then, the end of the corner L of the first layer is inserted between the delta corner D of the first layer and the inner shield S, and the corner L is applied to the edge corner of the inner shield S. Thereafter, other delta corners D and corners L are sequentially stacked on the outer surface of each delta corner D and corner L to form a multilayer structure. Note that if the end of the delta corner D that overlaps the outer periphery of the delta corner electrode DM is made longer, an overlapping portion between the end of the delta corner D and the corner L will be formed, thereby increasing the dielectric strength of the surface. It is advantageous to be able to do so. _S1 is a spacer made of an insulating material provided as necessary.

Delta corner electrode DM shown in Figures 2 and 3
The conductive layer E is formed by integrally molding an electrode plate on the inner surface of the molded article DC, but as shown in FIG. According to the present invention having such a configuration, the following effects are achieved.

(1) Even if the accuracy of the perpendicularity of the three planes of the molded material that constitutes the delta corner electrode is a little poor, even if there is a gap between the inner surface and the inner shield, the conductive layer of the delta corner electrode and the inner shield Since the potential gradient between is zero, no dielectric breakdown occurs in this part.

(2) Since the radius of curvature at the edge of the delta corner electrode is made larger than that of the inner shield, the potential gradient is lower than in the conventional configuration, and partial discharge characteristics can be improved. Even if the radius of curvature is increased in this manner, the internal shield does not become larger in any way.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the invention, Fig. 2 is a perspective view showing an embodiment of the invention;
3 is a perspective view of a delta corner electrode, FIG. 4 is a sectional view of a delta corner electrode showing another embodiment, and FIG. 5 is a sectional view of a conventional example. S...Internal shield, D...Delta corner, L
...Corner, DM...Delta corner electrode, E...
conductive layer.

Claims (1)

[Claims] 1. In high-voltage electrical equipment in which the main body of the electrical equipment is surrounded by an internal shield, and ground insulation is provided by applying a delta corner to the corner edge of the internal shield and an L-shaped corner to the corner edge, the innermost layer A delta corner electrode is interposed between the delta corner and the inner shield, the outer surface of which is an insulating material, the inner surface of which is a conductive layer, and each edge of which has a radius of curvature larger than that of the edge of the inner shield. A high-voltage electrical device in which a layer and the internal shield are connected with a conductor.