Corona shielding system, in particular outer corona shielding system for an electrical machine

Patent metadata

Field	Value
Publication number	US-10506748-B2
Application number	US-201515122271-A
Country	US
Kind code	B2
Filing date	Feb 25, 2015
Priority date	Feb 28, 2014
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

A corona shielding system for an electric machine, for example a high-voltage machine, such as a generator, for generating electrical energy, an electric motor or else other electric operating means having a relatively high rated voltage, such as transformers, bushings, cables, etc, is disclosed. The corona shielding system may include a filler mixture including both planar and spherical particles. Therefore, the electrical conductivity, which is good in the presence of only planar particles in two spatial directions but is very poor in the third, can be adjusted anisotropically in a targeted manner.

First claim

What is claimed is:

1. A corona shielding system for an electrical machine, the corona shielding system comprising:
a polymeric matrix;
a filler dispersed in the polymeric matrix, the filler comprising planar particles and spherical particles;
wherein the planar particles each comprise a planar core covered by a respective electrically conductive coating;
the spherical particles each comprise a spherical core covered by a respective electrically conductive coating; and
a concentration of the particles in the polymeric matrix exceeds 15% by weight of the corona shielding system so the system exceeds a percolation threshold for conductivity of the system along a first axis equivalent to a conductivity of the planar particles along a longest dimension.

2. The corona shielding system of claim 1 , wherein the polymeric matrix is produced from at least one of a thermoset, a thermoplastic, or an elastomer.

3. The corona shielding system of claim 1 , wherein:
the core of the planar particles and the core of the spherical particles are both resistant to partial discharges, and
the electrically conductive coating is resistant to partial discharges and electrically conductive.

4. The corona shielding system of claim 1 , wherein the spherical particles and the planar particles are contained in the filler approximately in a ratio of 1:3.

5. An electrical machine, comprising:
a plurality of machine components; and
a corona shielding system arranged proximate at least one of the machine components, the corona shielding system comprising:
a polymeric matrix; and
a filler dispersed in the polymeric matrix, the filler comprising both planar and spherical particles;
wherein the planar particles each comprise a planar core covered by a respective electrically conductive coating;
the spherical particles each comprise a spherical core covered by a respective electrically conductive coating; and
wherein a concentration of the particles in the polymeric matrix exceeds 15% by weight of the corona shielding system so the system exceeds a percolation threshold for conductivity of the system along a first axis equivalent to a conductivity of the planar particles along a longest dimension.

6. The electrical machine of claim 5 , wherein the polymeric matrix of the corona shielding system is produced from at least one of a thermoset, a thermoplastic, or an elastomer.

7. The electrical machine of claim 5 , wherein each of the particles in the filler comprises:
a core resistant to partial discharges, and
a coating that is resistant to partial discharges and is electrically conductive.

8. The electrical machine of claim 5 , wherein the spherical particles and the planar particles of the corona shielding system are contained in the filler approximately in a ratio of 1:3.

9. The electrical machine of claim 5 , wherein the electrical machine is a high-voltage machine.

10. The electrical machine of claim 5 , wherein the electrical machine is a generator or an electric motor.

Assignees

• Siemens Ag

Inventors

• Klaussner Bernhard
• Lang Jiri
• Lang Steffen
• Litinsky Alexander
• Schmidt Guido
• Schulz-Drost Christian
• Schaefer Klaus
• Staubach Christian

Classifications

• H02K3/40 Primary

  for high voltage, e.g. affording protection against corona discharges · CPC title

• C08K7/00

  Use of ingredients characterised by shape · CPC title

• C08K3/36

  Silica · CPC title

• C08K2003/2227

  of aluminium · CPC title

• H02K3/30

  Windings characterised by the insulating material · CPC title