JPH076907A - Tank-shaped lightning arrester - Google Patents

Abstract

PURPOSE:To make uniform the voltage distribution of non-linear element groups by a method wherein the nonlinear element groups and the blocks of a plurality of nonlinear resistors are connected by a connection fittings, and the position of arrangement of the connection fittings are made on the position surrounded by a connection supporting body. CONSTITUTION:A shade-like shield 6 is arranged on the high voltage side of a nonlinear element group 1. The voltage distribution rate of the nonlinear element group 1 of the tank type lightning arrester, on which a lower shield 8b is arranged on the low voltage side of the above-mentioned shape type shield 6 through the intermediary of a connection supporting body 7, becomes higher on the low voltage side of the shade type shield 6 and in the vicinity of the lower shield 8b, and it becomes lower in the vicinity of the connection supporting body 7. As a result, the arrangement part of a connection fitting 9, where local voltage distribution unbalance is generated, is used as the part surrounded by the connection supporting body 7 having the relatively low voltage distribution rate. As a result, even when the nonlinear element group 1 should be divided to cope with high system voltage, the voltage distribution of the nonlinear element group 1 can be made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tank type arrester equipped with a non-linear resistor (hereinafter referred to as a zinc oxide element) having zinc oxide as a main component and excellent in non-linearity.

[0002]

2. Description of the Related Art A lightning arrester using a zinc oxide element has excellent characteristics such as voltage-current non-linearity, discharge withstand voltage characteristic, and chemical stability. It is widely used in place of the lightning arrester that uses. In recent years, lightning arresters with even better protection characteristics have been developed and applied to high voltage systems such as 275kV and 500kV.

Further, this type of lightning arrester tends to be used with a high average stress (electric charge rate) at a system voltage that is constantly applied, and in order to ensure long-term reliability, individual oxidation arresters are used. The development of a voltage sharing equalization technique for making the sharing voltage of the zinc element uniform has become particularly important.

FIG. 3 shows an example of a conventional tank type lightning arrester. In the tank type lightning arrester shown in FIG. 3, the non-linear element group 1 in which zinc oxide elements are stacked has a vertically arranged ground tank 3 in which an insulating medium 2 having excellent insulating property such as SF ₆ gas is enclosed.
It is housed inside and is arranged coaxially with the ground tank 3. One end of the non-linear element group 1 in the axial direction (upper end in the figure)
Are connected to a substation bus (not shown) via a high-voltage side conductor 5 supported by an insulating spacer 4. As disclosed in Japanese Patent Publication No. Sho 64-1913, this tank type arrester is provided with an umbrella-shaped shield 6 on the high-voltage side of the non-linear element group 1 and on the low-pressure side of this umbrella-shaped shield 6. By arranging two or more lower shields, for example, the annular shield 8a via the connection support body 7 having a narrow width in the direction, the voltage sharing of the zinc oxide elements of the non-linear element group 1 is made uniform. The low voltage side of the nonlinear element group 1 is connected to the ground potential section.

When the system voltage is low, the non-linear element group 1 is formed by continuously stacking a zinc oxide element and an insulator from the high voltage side to the low voltage side. Therefore, the voltage sharing changes continuously, and the voltage sharing rate can be controlled to around 1.0 by disposing the umbrella-shaped shield 6 and the annular shield 8a at predetermined positions. FIG. 4 shows changes in the voltage share of the tank type arrester controlled by using the umbrella-shaped shield 6 and the annular shield 8a. As shown in Fig. 4, the voltage sharing ratio is 1.0, which is the boundary between the positive side and the negative side.
The change is within the voltage sharing ratio allowable range and is not a practical problem.

However, as the system voltage increases, the number of laminated zinc oxide elements and insulating plates increases and the weight also increases, making it difficult to secure the mechanical strength and electrical contact pressure of the non-linear element group. Therefore, the non-linear element group is divided into a plurality of blocks in the axial direction, and the blocks are connected to each other via connecting fittings.

5 (a) and 5 (b), the case where the non-linear element group 1 is continuously laminated and the case where the non-linear element group 1 is divided into a plurality of blocks The conceptual diagram of equipotential line distribution when connected is shown.

When the non-linear element group 1 is continuously laminated as shown in FIG. 5 (a), equipotential lines are at equal intervals, whereas the non-linear element group 1 is divided into blocks, and this block is divided into blocks. When the are connected via the connection fitting 9, the equipotential lines are locally narrowed near the connection fitting 9 as shown in FIG. 5B. This is because the connection fitting 9 does not share the voltage, and an imbalance in voltage distribution locally occurs in the non-linear element group 1 near the connection fitting 9.

Therefore, when the connecting fitting 9 is arranged at a position corresponding to the apex on the positive side of the voltage sharing ratio shown in FIG. 4, the voltage sharing ratio is provided at the installation position of the connecting fitting 9 as shown in FIG. There is a problem that the allowable range is exceeded and the voltage sharing becomes unbalanced.

[0010]

As described above, in the conventional tank type lightning arrester, the non-linear element group is divided into blocks in order to support the high voltage system, and when this block is connected through the connecting metal fittings, There is a problem that it is difficult to make the voltage distribution uniform because the voltage distribution is unbalanced at the installation position. Therefore, an object of the present invention is to provide a tank type lightning arrester in which the disturbance of voltage sharing due to the intervention of connecting fittings is reduced.

[0011]

To achieve the above object, in the present invention, a non-linear element group is housed by laminating a plurality of non-linear resistors in a grounding tank containing an insulating medium. Connect the ground potential part to the low voltage side of the element group,
An umbrella-shaped shield is arranged on the high pressure side of this non-linear element group,
In a tank type arrester in which a lower shield is disposed on the low-pressure side of this umbrella-shaped shield via a connection support, the non-linear element group connects a plurality of non-linear resistor blocks to each other by connecting a block of non-linear resistors. A tank-type lightning arrester characterized in that the connection metal fittings are connected to each other through a connection position, and the connection metal fitting is disposed at a position surrounded by the connection support body.

[0012]

[Function] The voltage sharing of the non-linear element group of the tank type arrester in which the umbrella-shaped shield is arranged on the high-voltage side of the non-linear element group, and the lower shield is arranged on the low-voltage side of the umbrella-shaped shield via the connection support. The rate increases near the low pressure side of the umbrella shield and near the lower shield, and decreases near the connection support. In the tank type lightning arrester of the present invention, the portion where the connecting metal in which a local unbalance of voltage sharing occurs is arranged is surrounded by the connecting support body having a relatively low voltage sharing rate. Therefore, even when the non-linear element group has to be divided in order to cope with a high system voltage, the voltage sharing of the non-linear element group can be made uniform.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. It should be noted that the same parts as the conventional ones are given the same numbers and their explanations are omitted. As shown in FIG. 1, a non-linear element group 1 in which zinc oxide elements are stacked is housed in a ground tank 3 in which an insulating medium 2 such as SF ₆ gas is sealed. The non-linear element group 1 is divided in the axial direction into, for example, two blocks, and these blocks are reconnected via a connecting fitting 9. The low potential side of the non-linear element group 1 is connected to the ground potential portion, the high voltage side of the non-linear element group 1 is provided with the umbrella-shaped shield 6, and the low pressure side of the umbrella-shaped shield 6 has a narrow circumferential width. A lower shield 8b is arranged via the connection support 7.
The non-linear element group 1 is divided so that the connection fittings 9 are arranged at positions surrounded by the connection support body 7. The high voltage side end of the non-linear element group 1 is connected to the high voltage side conductor 5 via an insulating spacer 4. An annular arcuate or spherical shield or the like can be used as the lower shield 8b.

The shape and arrangement of the umbrella-shaped shield 6 and the lower shield 8b are such that the charging current leaking from the non-linear element group 1 to the ground tank 3 at the ground potential and the current flowing into the non-linear element group 1 from the shield side are equal. Is determined based on the analysis and actual measurement.

Next, the operation will be described. A lower shield 8b is disposed on the low pressure side of the umbrella-shaped shield 6 via a connection support body 7 having a narrow width in the circumferential direction. For this reason, there is a sufficient space between the umbrella-shaped shield 6 and the lower shield 8 and the charging current leaking from the non-linear element group 1 located in this space to the ground tank 3 is made uniform in voltage sharing. Can be large enough.

Further, since the voltage sharing rate on the low voltage side of the non-linear element group 1 is relatively low, the lower shield 8b is arranged on the low voltage side as much as possible to raise the voltage sharing rate. Further, the voltage sharing ratio of the non-linear element group 1 on the high voltage side is lowered by disposing the umbrella-shaped shield 6 as high as possible. Therefore, as shown in FIG. 2, the voltage sharing rate of the non-linear element group 1 becomes relatively high at the low voltage side of the umbrella-shaped shield 6 and the position of the lower shield 8b. On the other hand, the umbrella-shaped shield 6 and the lower shield 8b
The voltage sharing ratio becomes relatively low at the position of the connection support 7 that connects the two.

According to this embodiment, the connecting metal fitting 9 for connecting the blocks formed by dividing the non-linear element group 1 is located at the central portion surrounded by the connecting support 7. Connection fitting 9
Although the voltage sharing locally becomes unbalanced at the arrangement position, since the voltage sharing ratio at this position is relatively low, the entire voltage sharing ratio can be controlled within the practical range.

Moreover, since the non-linear element group 1 can be divided, and sufficient mechanical strength and electrical contact pressure can be secured with a relatively simple structure, there is an effect that the reliability of the arrester is greatly improved.

[0019]

As described above, in the present invention, the blocks of the non-linear resistors are connected to each other through the connecting metal fittings to form a non-linear element group, and the arrangement positions of the connecting metal fittings are the umbrella-like shield and the umbrella-like shield. Since it is located at a position surrounded by the connection support body that connects the lower shield on the low voltage side, it is possible to provide a lightning arrester having a uniform voltage sharing ratio even if the non-linear element group is divided into blocks.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of a tank type arrester showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a voltage sharing ratio of the tank type lightning arrester shown in FIG.

FIG. 3 is a sectional view showing the overall configuration of a conventional tank type arrester.

FIG. 4 is a schematic diagram showing a voltage sharing ratio of the tank type lightning arrester shown in FIG.

5 (a) and 5 (b) are conceptual diagrams showing equipotential line distributions of non-linear element portions.

FIG. 6 is a schematic diagram showing a voltage sharing ratio when a connection fitting is used in a conventional tank type lightning arrester.

[Explanation of symbols]

1 ... Non-linear element group, 2 ... Insulating medium, 3 ... Ground tank, 6
... umbrella-shaped shield, 7 ... connection support, 8b ... lower shield, 9 ... connection fitting.

Claims (1)

[Claims] 1. A non-linear element group is accommodated by stacking a plurality of non-linear resistors in a grounded tank containing an insulating medium, and a ground potential portion is connected to the low voltage side of the non-linear element group. A tank type arrester in which an umbrella-shaped shield is arranged on the high-voltage side of the element group, and a lower shield is arranged on the low-pressure side of the umbrella-shaped shield via a connection support, in which the non-linear element group is the non-linear resistance A tank type characterized in that a plurality of non-linear resistor blocks in which bodies are laminated are connected via connecting metal fittings, and the arrangement position of the connecting metal fittings is a position surrounded by the connection support body. Lightning arrester.