JPS598006B2 - butsing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bushing used in ultra-high voltage electrical equipment such as transformers, oil immersors, and circuit breakers. This relates to improved bushings.

Figure 1 is a cross-sectional view showing one half of a conventional bushing of this type, where 1 is the center conductor and 2 is SF6 gas (sulfur hexafluoride gas).
3 is an insulating medium, 4 is a grounding electrode, 5 is a grounding shield, 6 is the atmosphere, and 7 is an equipotential line. Each component in a conventional bushing is arranged as shown in Figure 1. Above, the equipotential line is the ground electrode 4 inside the insulator tube 3.
The electric field tends to concentrate around the tip of the insulator tube 3, the lower part of the insulator tube 3, and the ground shield 5, which has the disadvantage that the withstand voltage is limited.

This invention was made with attention to this point, and by providing an intermediate electrode between a pair of concentric ceramic tubes and connecting the intermediate electrode and the ground electrode with each other via a capacitor, local electric field concentration is achieved. The purpose of this invention is to provide a bushing that eliminates this problem.

That is, FIG. 2 shows one embodiment of this invention.
1 is a center conductor, 2 is an insulating medium such as SF6 gas (sulfur hexafluoride gas), 3a and 3b are a pair of split insulator tubes arranged concentrically, and 4 is a ground connected to the lower end of one insulator tube 3b. Electrode, 5 is ground shield, 6 is atmosphere, □ is equipotential line, 8
9 is an intermediate shield, 9 is an intermediate electrode interposed between the two divided insulator tubes 3a and 3b, and 10 is a capacitor of a predetermined capacity electrically connected between the intermediate electrode 9 and the ground electrode 4.

It should be noted that, instead of being a force that allows the potential of the intermediate electrode 9 to be arbitrarily set by appropriately changing the capacitance of the capacitor 10, the capacitor 10 may be supported entirely over its entire circumference. , it goes without saying that similar effects can be obtained even if the capacitor is partially supported. As described above, in the bushing of the present invention, an intermediate electrode 8 is provided between the pair of concentric divided insulator tubes 3a and 3b through which the central conductor 1 is inserted approximately in the center, and a capacitor 10 is connected between the intermediate electrode 8 and the ground electrode 4. As shown in Fig. 2, the equipotential lines are almost uniformly distributed over the entire length of the bushing, and the local electric field as in the conventional one described above is avoided. This has the excellent effect of eliminating concentration, and of course greatly improving the withstand voltage of the bushing.

Further, according to the present invention, a pair of concentric segmented insulator tubes 3a, 3
Since it has a simple structure in which the intermediate electrode 8 is interposed between the intermediate electrode 8 and the ground electrode 4, and the capacitor 10 is simply inserted between the intermediate electrode 8 and the ground electrode 4, its assembly is extremely simple and can be manufactured at low cost. Moreover, it also has the effect of providing highly accurate bushing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one half of a conventional bushing, and FIG. 2 is a sectional view showing one embodiment of the present invention.

Claims (1)

[Claims] 1. An intermediate electrode is provided between concentric insulator tubes with a central conductor inserted through the center, and the intermediate electrode and the ground electrode are connected to each other via a capacitor of a predetermined capacity to adjust the potential of the intermediate electrode. A bushing characterized by eliminating electric field concentration.