JPS6337567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas insulated busbar device having a built-in lightning arrester therein.

[Technical background of the invention and its problems]

Recently, gas-insulated switchgears are mainly installed as power receiving and transforming equipment. This gas-insulated switchgear has gas-insulated circuit breakers, disconnectors, busbars, lightning arresters, and the like, which are combined together to form a comprehensive device. Among these, for surge arresters for gas-insulated switchgear, the surge arrester element is housed in a tank independent of the busbar, and this is connected to the busbar by branching, but it is combined by branching and connecting via a dedicated disconnector. .

Tank-type lightning arresters configured in this way are inevitably large in size and require a lot of space, but for gas-insulated switchgear with the aim of downsizing, it is possible to reduce the size by coordinating with other equipment. There is room for improvement. In other words, in an independent tank type arrester, an internal element such as a ZnO element, a support member for this element, a potential sharing control element such as a capacitor or a shield ring, a tank, a spacer for the arrester, and in some cases a set of special disconnectors for the arrester. If the necessary insulation distance is required, the lightning arrester will be large, occupy a large amount of space in the substation, and will be expensive.

On the other hand, with the recent appearance of ZnO elements, surge arresters with built-in busbars have been considered, but simply arranging ZnO elements between the busbar and the tank perpendicular to the busbar direction still poses many problems, making it impractical. Not.
Many ZnO elements must be connected in series, and the distance between the conductor and the tank is small, so
ZnO element cannot be inserted. The stray capacitance between the ZnO element and the tank disturbs the potential distribution of the element, which requires separate potential sharing control in high-voltage arresters, resulting in a complex structure. These are problems that must be solved in a gas-insulated busbar system that includes a built-in lightning arrester.

Furthermore, since gas insulated busbar equipment has a sealed structure, it is necessary to avoid internal ground faults and corona generation as much as possible. A conventional lightning arrester with a built-in gas-insulated bus bar includes one in which ZnO elements are arranged side by side on the outer surface of a cone-shaped insulating spacer that supports the bus conductor. However, with this arrangement of ZnO elements, the recess formed by the outer surface of the cone-shaped insulating spacer and the bottom of the sealed container may become a weak point for ground faults or corona generation. It is not preferable to arrange the ZnO element on the outer surface of the .

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas-insulated busbar device having a built-in lightning arrester in a compact manner.

[Summary of the invention]

The present invention relates to a gas-insulated busbar device characterized in that ZnO elements are arranged on the inner surface of a cone-shaped insulating spacer that insulates and supports a busbar conductor in a busbar container.

[Embodiments of the invention]

The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 1, a busbar conductor 2 disposed in busbar containers 1, 1 containing SF ₆ gas is firmly insulated and supported by the containers 1, 1 via an insulating spacer 3. That is, the insulating spacer 3 is molded into a cone shape as shown in the figure by casting epoxy resin, and its inner periphery is electrically connected to the conductor 2 with a contact fitting 4, and its outer periphery is connected to the containers 1, 1. It is firmly mechanically supported by being clamped by the connecting flanges 5, 5. In FIG. 1, a diagonal hole 6 is provided on the inner surface of the insulating spacer 3 and extends from the inner surface of the container 1 to the outer surface of the conductor 2.
A predetermined number of elements 8 are connected in series and inserted, the element 8a at one end is connected to the container 1, the element 8b at the other end is electrically connected to the conductor 2, and the element 8 at the end is connected to the container 1.
a, 8b and the central element 8 are connected by a metal fitting 9. Finally, by covering the outside of the hole 6 with an insulating barrier 10, the built-in lightning arrester is completed. Especially ZnO
Since the element 8 is placed on the inner surface of the cone-shaped insulating spacer 3, where there is a relatively large space, avoiding the outer surface of the cone-shaped insulating spacer 3, it is easy to insert the ZnO element 8 into the hole 6 and assemble it. It can protect against ground faults and corona outbreaks.

The distribution of stray capacitance for the built-in ZnO element 8 as shown in FIG. 1 is shown by the equivalent circuit shown in FIG. This means that two parallel ZnO elements 8, 8 are connected between the conductor 2 and the bus bar container 1 at ground potential. This means that the element 8 is arranged diagonally with respect to the conductor 2, and the conductor 2 acts as an effective potential correction for the ZnO element 8, resulting in a nearly uniform potential distribution.

That is, in FIG. 2, if the potential correction effect by the conductor 2 is not considered, the potential distribution of the ZnO element 8 is disturbed by the stray capacitances C ₁ to _{C o} with respect to the container 1, and the potential distribution line V in FIG. ₁ , which is very different from the ideal distribution V ₀ . Therefore, the closer an element is to a live part, the stronger the electric field becomes, leading to deterioration in life characteristics and the like. However, as in the present invention, between the capacitances C ₁₁ to _{C 1o} between the conductor 2 and the diagonal element 8, C ₁₁ > C ₁₂ > C ₁₃ ...> C _1o ... (1) The stray capacitance between the element 8 and the container 1 has the following relationship: C ₁ <C ₂ <C ₃ ...<C _o ...(2), and both of these relationships 1 and 2 are
Since the potential distribution of the ZnO element 8 is made uniform, the potential distribution line C ₂ in FIG. 3 becomes a curve close to the ideal distribution V ₀ . Therefore, there is no need to provide a special capacitor or other special shield, and the structure can be simple.

The relationship between the hole 6 and the insulating spacer 3 is such that the hole 6 is provided in the spacer 3 to cover the insulating barrier 10 as shown in FIG. 4a, and the round hole 6 is provided in the insulating spacer 3 itself as shown in FIG. Alternatively, as shown in FIG. 4c, the insulating barrier 10 may be shaped to accommodate the ZnO element 8 without being processed on the insulating spacer 3 side and arranged side by side with the insulating spacer 3. Also, although the case where two ZnO elements 8 are arranged in parallel is shown, it is generally possible to arrange them in N parallels (N≧1), and as the number of parallels N increases, the cross-sectional area of one ZnO element 8 becomes smaller accordingly. is possible and is structurally compact.

〔Effect of the invention〕

As described above, in the present invention, the ZnO element is arranged diagonally on the cone-shaped inner surface of the insulating spacer that is insulated and supported on the busbar container, so that the ZnO element can be compacted in the limited space within the busbar. They can be arranged in large numbers in series, and the capacitance between the conductor and ZnO element compensates for the stray capacitance between the ZnO element and the ground, improving uniform potential distribution. Effects such as Also, on the inner surface of the cone-shaped insulating spacer
By arranging the ZnO element, it is easy to insert and assemble the ZnO element, and it can protect against ground faults and corona generation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the gas insulated bus device according to the present invention, FIG. 2 is an equivalent circuit diagram of the capacitance distribution by the gas insulated bus device according to the present invention, and FIG. 3 is the potential distribution of the lightning arrester. Curve diagram, Figure 4 a, b,
3c is a cross-sectional view showing another embodiment of the lightning arrester insertion part according to the present invention. 1... Busbar container, 2... Busbar conductor, 3... Insulating spacer, 4... Contact fitting, 5... Connection flange, 6... Hole,
8... ZnO element, 9... Connection fitting, 10... Insulating barrier, C ₁ , C ₂ ... C _o ... Ground floating capacitance, C ₁₁ , C ₁₂
...C _1o ...to-conductor capacitance.

Claims (1)

[Scope of Claims] 1. A cone-shaped insulating spacer that insulates and supports a bus conductor in a bus container filled with an insulating gas, and a cone-shaped insulating spacer that is diagonally arranged and supported on the inner surface of the insulating spacer and has one end connected to the bus container. consisting of a required number of rows of ZnO element lightning arresters whose other ends are connected to the bus conductor,
The capacitance between the bus conductor and each ZnO element is large, and the stray capacitance between each element and the container is large, and the stray capacitance between each element and the container is large. A gas insulated busbar device characterized in that it is characterized in that it increases in size. 2. The gas insulated busbar device according to claim 1, wherein the ZnO element is inserted into a diagonally formed hole on the inner surface of the insulating spacer, and the outside thereof is covered with an insulating barrier. 3 The ZnO element is inserted into a tubular insulation barrier,
The gas insulated busbar device according to claim 1, wherein the gas insulated busbar device is installed obliquely on the inner surface of the insulating spacer.