Gas-insulated switchgear

Patent metadata

Field	Value
Publication number	US-10069285-B2
Application number	US-201515325196-A
Country	US
Kind code	B2
Filing date	Jul 16, 2015
Priority date	Nov 20, 2014
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A gas-insulated switchgear includes a grounded tank filled with insulation gas, a center conductor which is disposed in the grounded tank and to which a voltage is applied, an insulating support member which insulates and supports the center conductor, and a nonlinear resistive part disposed at least on a vertically lower side inner surface of the grounded tank and formed by an insulation material containing a nonlinear resistive material. If an electric field applied to the nonlinear resistive part is higher than an electric field value in a vicinity of a contact point between the nonlinear resistive part and a metallic foreign substance mixed in the grounded tank during an operation, a resistivity of the nonlinear resistive part at the center conductor side is lower than a resistivity at which a discharge delay time is equal to an electric field relaxation time constant.

First claim

The invention claimed is:

1. A gas-insulated switchgear comprising:
a grounded tank filled with gas;
a center conductor which is disposed in the grounded tank and to which a voltage is applied;
an electrically insulating support member which is attached to the grounded tank and which electrically insulates and supports the center conductor; and
a nonlinear resistive part which is disposed at least on a vertically lower side inner surface of the grounded tank and which is formed by an electrically insulating material containing a nonlinear resistive material, wherein
if an electric field applied to the nonlinear resistive part is higher than an electric field value in a vicinity of a contact point between the nonlinear resistive part and a metallic foreign substance mixed in the grounded tank when an operation voltage is applied but no electric field relaxation has occurred, a resistivity of the nonlinear resistive part is lower than a resistivity at which a discharge delay time is equal to an electric field relaxation time constant.

2. The gas-insulated switchgear according to claim 1 , wherein the switchgear includes an electrically insulating film between the grounded tank and the nonlinear resistive part.

3. The gas-insulated switchgear according to claim 1 , wherein the resistivity of the nonlinear resistive part at the center conductor side is a value at which a product of a vacuum permittivity, a relative permittivity of the nonlinear resistive part, and a resistivity of the nonlinear resistive part is less than 50 ns.

4. The gas-insulated switchgear according to claim 1 , wherein the nonlinear resistive part contains the nonlinear resistive material in a larger amount at the center conductor side than that at the grounded tank side.

5. The gas-insulated switchgear according to claim 4 , wherein a content ratio of the nonlinear resistive material at the center conductor side falls within a range determined on the basis of a condition for causing the nonlinear resistive part to exhibit a nonlinear resistive characteristic and securing desired strength of the nonlinear resistive part.

6. The gas-insulated switchgear according to claim 1 , wherein the nonlinear resistive part is a coating film formed by an electrically insulating coating material as the electrically insulating material containing the nonlinear resistive material.

7. The gas-insulated switchgear according to claim 6 , wherein the coating film includes a plurality of layers formed by performing coating a plurality of times while the content ratio of the nonlinear resistive material is changed.

8. The gas-insulated switchgear according to claim 7 , wherein the content ratio of the nonlinear resistive material increases stepwise from the grounded tank side toward the center conductor side.

9. The gas-insulated switchgear according to claim 6 , wherein the nonlinear resistive material has a lower specific gravity than the electrically insulating material.

10. The gas-insulated switchgear according to claim 9 , wherein the content ratio of the nonlinear resistive material increases continuously from the grounded tank side toward the center conductor side.

11. The gas-insulated switchgear according to claim 1 , wherein the nonlinear resistive part is a nonlinear resistive sheet formed by an electrically insulating coating material as the electrically insulating material containing the nonlinear resistive material.

12. The gas-insulated switchgear according to claim 11 , wherein the content ratio of the nonlinear resistive material increases continuously from the grounded tank side toward the center conductor side.

13. The gas-insulated switchgear according to claim 6 , wherein the nonlinear resistive material has a higher thermal conductivity than the electrically insulating material.

14. A gas-insulated switchgear comprising:
a grounded tank filled with gas;
a center conductor which is disposed in the grounded tank and to which a voltage is applied;
an electrically insulating support member which is attached to the grounded tank and which electrically insulates and supports the center conductor;
a first nonlinear resistive part which is disposed at least on a vertically lower side inner surface of the grounded tank and which is formed by a first electrically insulating material containing a first nonlinear resistive material; and
a second nonlinear resistive part which is disposed on a surface of the first nonlinear resistive part and which is formed by a second electrically insulating material containing a second nonlinear resistive material, wherein
an electric field intensity at which a resistivity of the first nonlinear resistive part changes is higher than that of the second nonlinear resistive part.

15. The gas-insulated switchgear according to claim 14 , wherein the resistivity of the first nonlinear resistive part in an electric field region having an intensity lower than the electric field intensity at which the resistivity of the first nonlinear resistive part changes is higher than the resistivity of the second nonlinear resistive part in an electric field region having an intensity lower than the electric field intensity at which the resistivity of the second nonlinear resistive part changes.

16. The gas-insulated switchgear according to claim 1 , wherein the nonlinear resistive material is silicon carbide or zinc oxide.

17. The gas-insulated switchgear according to claim 1 , wherein the nonlinear resistive material is a mixture of a plurality of types selected from among silicon carbide, zinc oxide, gallium nitride, and diamond.

Assignees

• Mitsubishi Electric Corp

Inventors

• Kainaga Soichiro
• Kawano Ryoko
• Yoshimura Manabu
• Tsurimoto Takao
• Nakauchi Shinichiro

Classifications

• H02B13/01 Primary

  with resin casing · CPC title

• H02B13/045

  Details of casing, e.g. gas tightness · CPC title

• H02G5/065 Primary

  Particle traps (gettering in vacuum switches H01H33/6683; in discharge or vacuum tubes H01J7/18, H01J19/70) · CPC title