EP4293696A1

EP4293696A1 - Medium voltage or high voltage equipment

Info

Publication number: EP4293696A1
Application number: EP22179003.3A
Authority: EP
Inventors: Christian Reuber; Dietmar Gentsch
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2023-12-20

Abstract

The present invention relates to a medium voltage or high voltage equipment, comprising:- a first part (20);- a second part (10);- a field control element (100);wherein the first part is formed from a conducting material;wherein the second part is formed from an insulating material;wherein the first part is connected to the second part at a junction;wherein the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage;wherein the field control element is formed from a conducting material; andwherein the field control element is located in contact with an outer surface of the first part, and wherein the field control element is located adjacent to the junction.

Description

FIELD OF THE INVENTION

The present invention relates to a medium voltage or high voltage equipment, a field control element, a method of manufacturing a medium voltage or high voltage equipment, and a method of providing field control for a medium voltage or high voltage equipment.

BACKGROUND OF THE INVENTION

Medium voltage (MV) and high voltage (HV) equipment often uses combinations of conducting material and several insulating gases and / or solid insulating materials that can have different dielectric constants.
Locations where three different materials come together, so-called triple points, can show strongly increased dielectric stress, for example a connection of a conductor to a solid insulator that is surrounded by air, when the dielectric constant of the solid insulator is higher than the dielectric constant of the surrounding air.
In the situation when dielectric stress is too high, dedicated electric shields have to be added. These shields have to be designed and manufactured according to the device that they protect. A way for mechanical fixation has to be found. Also a way for electrically contacting the shields has to be found.
There is a need to address these issues.

SUMMARY OF THE INVENTION

Therefore, it would be advantageous to have an improved mechanism to mitigate for the effects associated with triple points for medium voltage and high voltage equipment.
The object of the present invention is solved with the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.
In a first aspect, there is provided a medium voltage or high voltage equipment, comprising:

a first part;
a second part; and
a field control element.

The first part is formed from an electrically conducting material. The second part is formed from an electrically insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The field control element is formed from a conducting material. The field control element is located in contact with an outer surface of the first part, and the field control element is located adjacent to the junction.
In an example, the first part where it connects to the second part has a circular cross section, and the second part where it connects to the first part has a circular cross section. The junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
In an example, the field control element encircles the first part.
In an example, the field control element is located in contact with the outer surface of the first part around an outer circumference of the first part. Before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than the outer circumference of the first part.
In an example, the field control element is located such that it does not contact the second part.
In an example, the field control element has a substantially toroidal shape.
In an example, the field control element comprises a spiral wire, a spiral contact or a spiral spring.
In an example, the medium voltage or high voltage equipment further comprises an insulating medium. The insulating medium encapsulates at least the first part, the second part and the field control element.
In an example, the medium voltage or high voltage equipment further comprises a third part. The third part is formed from a conducting material. The third part is connected to the second part at a second junction. The medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
In an example, the medium voltage or high voltage equipment further comprises a second field control element. The second field control element is formed from a conducting material. The second field control element is located in contact with an outer surface of the third part, and the second field control element is located adjacent to the second junction.
In an example, the first part, the second part and the field control element form at least part of a vacuum interrupter.
In an example, the medium voltage or high voltage equipment further comprises a pole housing. The vacuum interrupter is located inside the pole housing, and a gap between the vacuum interrupter and the pole housing is filled with an insulating material.
In a second aspect, there is provided a field control element for a medium voltage or high voltage equipment. The medium voltage or high voltage equipment comprises a first part, and a second part. The first part is formed from a conducting material. The second part is formed from an insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The field control element is formed from a conducting material. The field control element is configured to be located in contact with an outer surface of the first part adjacent to the junction.
In third aspect, there is provided a method of manufacturing a medium voltage or high voltage equipment, comprising:

connecting a first part to a second part at a junction, wherein the first part is formed from a conducting material, and wherein the second part is formed from an insulating material;
locating a field control element in contact with an outer surface of the first part adjacent to the junction, and wherein the field control element is formed from a conducting material; and
wherein once manufactured the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage.

In an fourth aspect, there is provided a method of providing field control for a medium voltage or high voltage equipment. The medium voltage or high voltage equipment comprises a first part, and a second part. The first part is formed from a conducting material, and the second part is formed from an insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The method comprises locating a field control element in contact with an outer surface of the first part adjacent to the junction, and the field control element is formed from a conducting material.
The above aspects and examples will become apparent from and be elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will be described in the following with reference to the following drawings:

Fig. 1 shows an example of a medium voltage or high voltage equipment in the form of a vacuum interrupter with a field control element in the form of a spiral wire ring;
Fig. 2 shows an example of a medium voltage or high voltage equipment in the form of a vacuum interrupter without a field control element;
Fig. 3 shows a field calculation in the region of a triple point for the medium voltage or high voltage equipment of Fig. 2; and
Fig. 4 shows a field calculation in the region of a triple point for the medium voltage or high voltage equipment of Fig. 1.

DETAILED DESCRIPTION OF EMBODIMENTS

A new medium voltage or high voltage equipment, a new field control element, a new method of manufacturing a medium voltage or high voltage equipment, and a new method of providing field control for a medium voltage or high voltage equipment are now described.
In an example a medium voltage or high voltage equipment comprises a first part 20, a second part 10, and a field control element 100. The first part is formed from a conducting material. The second part is formed from an insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The field control element is formed from a conducting material. The field control element is located in contact with an outer surface of the first part, and the field control element is located adjacent to the junction.
According to an example, the first part where it connects to the second part has a circular cross section, and the second part where it connects to the first part has a circular cross section. The junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
According to an example, the field control element encircles the first part.
According to an example, the field control element is located in contact with the outer surface of the first part around an outer circumference of the first part. Before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than the outer circumference of the first part.
According to an example, the field control element is located such that it does not contact the second part.
In an example, the field control element has a substantially circular cross section.
In an example, the field control element has a substantially annular cross section.
In an example, the field control element has a ring shape.
According to an example, the field control element has a substantially toroidal shape.
According to an example, the field control element comprises a spiral wire, a spiral contact or a spiral spring.
According to an example, the medium voltage or high voltage equipment further comprises an insulating medium. The insulating medium encapsulates at least the first part, the second part and the field control element.
According to an example, the medium voltage or high voltage equipment further comprises a third part 30. The third part is formed from a conducting material. The third part is connected to the second part at a second junction. The medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
According to an example, the medium voltage or high voltage equipment further comprises a second field control element. The second field control element is formed from a conducting material. The second field control element is located in contact with an outer surface of the third part, and the second field control element is located adjacent to the second junction.
According to an example, the first part, the second part and the field control element form at least part of a vacuum interrupter.
According to an example, the medium voltage or high voltage equipment further comprises a pole housing. The vacuum interrupter is located inside the pole housing, and a gap between the vacuum interrupter and the pole housing is filled with an insulating material.
In an example, the medium voltage or high voltage equipment is configured to operate in an air or gas environment.
In an example, the dielectric constant of the insulating material of the second part is greater than the dielectric constant of air or the gas.
In an example a field control element 100 can be retrofitted to a medium voltage or high voltage equipment. The medium voltage or high voltage equipment comprises a first part 20, and a second part 10. The first part is formed from a conducting material, and the second part is formed from an insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The field control element is formed from a conducting material; and the field control element is configured to be located in contact with an outer surface of the first part adjacent to the junction.
In an example, the first part where it connects to the second part has a circular cross section, and the second part where it connects to the first part has a circular cross section. The junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
In an example, the field control element is configured to encircle the first part when it is located in contact with the outer surface of the first part adjacent to the junction.
In an example, the field control element is configured to be located in contact with the outer surface of the first part around an outer circumference of the first part. Before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than the outer circumference of the first part.
In an example, the field control element is configured to be located such that it does not contact the second part.
In an example, the field control element has a substantially circular cross section.
In an example, the field control element has a substantially annular cross section.
In an example, the field control element has a substantially toroidal shape.
In an example, the field control element comprises a spiral wire, a spiral contact or a spiral spring.
In an example, the medium voltage or high voltage equipment further comprises a third part 30. The third part is formed from a conducting material. The third part is connected to the second part at a second junction. The medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
In an example, the first part, the second part and the field control element form at least part of a vacuum interrupter.
In an example, the medium voltage or high voltage equipment is configured to operate in an air or gas environment.
In an example, the dielectric constant of the insulating material of the second part is greater than the dielectric constant of air or the gas.
In an example, a method of manufacturing a medium voltage or high voltage equipment comprises:

connecting a first part 20 to a second part 10 at a junction, wherein the first part is formed from a conducting material, and wherein the second part is formed from an insulating material;
locating a field control element 100 in contact with an outer surface of the first part adjacent to the junction, and wherein the field control element is formed from a conducting material; and
wherein once manufactured the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage.

In an example, the first part where it connects to the second part has a circular cross section, and the second part where it connects to the first part has a circular cross section. The junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
In an example, the method comprises encircling the first part with the field control element.
In an example, the field control element is located in contact with the outer surface of the first part around an outer circumference of the first part. Before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than the outer circumference of the first part.
In an example, the method comprises locating the field control element such that it does not contact the second part.
In an example, the field control element has a substantially circular cross section.
In an example, the field control element has a substantially annular cross section.
In an example, the field control element has a substantially toroidal shape.
In an example, the field control element comprises a spiral wire, a spiral contact or a spiral spring.
In an example, the method comprises encapsulating at least the first part, the second part and the field control element with an insulating medium.
In an example, the method comprises connecting a third part to the second part at a second junction. The third part is formed from a conducting material, and once manufactured the medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
In an example, the method comprises locating a second field control element in contact with an outer surface of the third part adjacent to the second junction, and wherein the second field control element is formed from a conducting material.
In an example, the first part, the second part and the field control element form at least part of a vacuum interrupter.
In an example, the method comprises locating the vacuum interrupter inside a pole housing, and filling a gap between the vacuum interrupter and the pole housing with an insulating material.
In an example, the medium voltage or high voltage equipment once manufactured is configured to operate in an air or gas environment.
In an example, the dielectric constant of the insulating material of the second part is greater than the dielectric constant of air or the gas.
In an example a method of providing field control for a medium voltage or high voltage equipment via utilization of a field control element 100 is as follows. The medium voltage or high voltage equipment comprises a first part 20, and a second part 10. The first part is formed from a conducting material, and the second part is formed from an insulating material. The first part is connected to the second part at a junction. The medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage. The method comprises locating a field control element 100 in contact with an outer surface of the first part adjacent to the junction, and the field control element is formed from a conducting material.
In an example, the first part where it connects to the second part has a circular cross section, and the second part where it connects to the first part has a circular cross section. The junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
In an example, the method comprises encircling the first part with the field control element when it is located in contact with the outer surface of the first part adjacent to the junction.
In an example, before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than an outer circumference of the first part.
In an example, the method comprises locating the field control element such that it does not contact the second part.
In an example, the field control element has a substantially circular cross section.
In an example, the field control element has a substantially annular cross section.
In an example, the field control element has a substantially toroidal shape.
In an example, the field control element comprises a spiral wire, a spiral contact or a spiral spring.
In an example, the medium voltage or high voltage equipment further comprises a third part 30. The third part is formed from a conducting material. The third part is connected to the second part at a second junction. The medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
In an example, the first part, the second part and the field control element form at least part of a vacuum interrupter.
In an example, the medium voltage or high voltage equipment is configured to operate in an air or gas environment.
In an example, the dielectric constant of the insulating material of the second part is greater than the dielectric constant of air or the gas.
The new medium voltage or high voltage equipment, the new field control element, the new method of manufacturing a medium voltage or high voltage equipment, and the new method of providing field control for a medium voltage or high voltage equipment are now described in specific detail, where reference is made to Figs. 1-4.
The following relates to a field control element in the form of a standard spiral wire or spiral contact or spiral spring used for electrically shielding triple points..
Fig. 2 shows a typical MV vacuum interrupter (VI) as an example for the creation of a triple point. The insulating ceramic 10 (also called second part) is connected to the upper and lower lid 20, 30 (also called first and third parts) that are made from conductive sheet metal. At the very ends of the VI, upper and lower terminals 40, 50 can be seen.
The triple point 60 is the connection of the ceramic to the upper lid (there is also another triple point at the connection of the ceramics to the lower lid).
Fig. 1 shows the same VI where the region of the triple point 60 is shielded by a standard spiral wire ring 100 (also called a field control element). These spiral wires have been widely being used in MV but for other purposes. They typically do not have to be designed for a certain application, and they can easily be added to the VI. The electrical contact to the lid is established automatically when the inner diameter of the spiral wire is smaller than the diameter of the lid. The spring property of the spiral contact will generate some contact force to maintain the electrical contact also in case of vibrations and temperature changes.
Fig. 3 shows a field calculation of this region, where there is no field control element 100 present. 10 is a section of the ceramic, 20 is a section of the upper lid, 60 is the triple point where 10 and 20 touch. The upper lid 20 is charged to the operation voltage. 70 is an earthed reference plate. The lines from line 80 to the right are equipotential lines that are running in air in this example. It can be seen that the first equipotential line 80 passes closely to the triple point 60. This will result in a relatively high dielectric stress in the region of the triple point 60. The result can be that a certain dielectric rating cannot be fulfilled or that partial discharges occur.
Fig. 4 shows a field calculation of the same region with spiral wire (field control element) 100 present. The conductive spiral wire takes over the electric potential from the upper lid 20 and forces the first equipotential line 80 away from the triple point. Thus, the dielectric stress in that region is reduced. The result is a certain dielectric rating can be fulfilled and that the occurrence of partial discharges is prevented.
It is to be noted that as shown above the spiral wire does not touch the insulator 10, because this would create a new triple point.
It is further to be noted that it is possible to encapsulate the VI together with the spiral wire with a solid insulating medium like silicone or silicone. This will also fix the spiral wire to the VI at the desired position. It is further possible and advantageous to assemble the VI together with the spiral wire in a pole housing.
It is further possible and advantageous to fill the gap between the pole housing and the VI together with the spiral wire with an insulating material, e.g. a potting material.
It is to be noted that the above description relating to a medium voltage or high voltage equipment in the form of a vacuum interrupter is only for explanatory purposes. The utilization of the filed control element, that need not be a spiral wire or spring, application is not limited to vacuum interrupters. It can be universally used to cover regions in switchgears or on other electrical components for local reduction of the electric field strength.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing a claimed invention, from a study of the drawings, the disclosure, and the dependent claims.

Claims

A medium voltage or high voltage equipment, comprising:
- a first part (20);

- a second part (10);

- a field control element (100);

wherein the first part is formed from a conducting material;

wherein the second part is formed from an insulating material;

wherein the first part is connected to the second part at a junction;

wherein the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage;

wherein the field control element is formed from a conducting material; and

wherein the field control element is located in contact with an outer surface of the first part, and wherein the field control element is located adjacent to the junction.
Medium voltage or high voltage equipment according to claim 1, wherein the first part where it connects to the second part has a circular cross section, wherein the second part where it connects to the first part has a circular cross section, wherein the junction is formed from the connection of the circular cross section of the first part with the circular cross section of the second part.
Medium voltage or high voltage equipment according to any of claims 1-2, wherein the field control element encircles the first part.
Medium voltage or high voltage equipment according to claim 3, wherein the field control element is located in contact with the outer surface of the first part around an outer circumference of the first part, and wherein before being located in contact with the outer surface of the first part an inner circumference of the field control element is less than the outer circumference of the first part.
Medium voltage or high voltage equipment according to any of claims 1-4, wherein the field control element is located such that it does not contact the second part.
Medium voltage or high voltage equipment according to any of claims 1-5, wherein the field control element has a substantially toroidal shape.
Medium voltage or high voltage equipment according to any of claims 1-6, wherein the field control element comprises a spiral wire, a spiral contact or a spiral spring.
Medium voltage or high voltage equipment according to any of claims 1-7, further comprising an insulating medium, wherein the insulating medium encapsulates at least the first part, the second part and the field control element.
Medium voltage or high voltage equipment according to any of claims 1-8, further comprising a third part (30);
wherein the third part is formed from a conducting material;

wherein the third part is connected to the second part at a second junction;

wherein the medium voltage or high voltage equipment is configured such that an operational potential difference can be applied between the first part and the third part.
Medium voltage or high voltage equipment according to claim 9, further comprising a second field control element, wherein the second field control element is formed from a conducting material, and wherein the second field control element is located in contact with an outer surface of the third part, and wherein the second field control element is located adjacent to the second junction.
Medium voltage or high voltage equipment according to any of claims 1-10, wherein the first part, the second part and the field control element form at least part of a vacuum interrupter.
Medium voltage or high voltage equipment according to claims 11, further comprising a pole housing, wherein the vacuum interrupter is located inside the pole housing, and wherein a gap between the vacuum interrupter and the pole housing is filled with an insulating material.
A field control element (100) for a medium voltage or high voltage equipment, wherein the medium voltage or high voltage equipment comprises a first part (20), and a second part (10), wherein the first part is formed from a conducting material, wherein the second part is formed from an insulating material, wherein the first part is connected to the second part at a junction, wherein the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage; wherein the field control element is formed from a conducting material; and wherein the field control element is configured to be located in contact with an outer surface of the first part adjacent to the junction.
A method of manufacturing a medium voltage or high voltage equipment, comprising:
connecting a first part (20) to a second part (10) at a junction, wherein the first part is formed from a conducting material, and wherein the second part is formed from an insulating material;

locating a field control element (100) in contact with an outer surface of the first part adjacent to the junction, and wherein the field control element is formed from a conducting material; and

wherein once manufactured the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage.
A method of providing field control for a medium voltage or high voltage equipment, wherein the medium voltage or high voltage equipment comprises a first part (20), and a second part (10), wherein the first part is formed from a conducting material, wherein the second part is formed from an insulating material, wherein the first part is connected to the second part at a junction, wherein the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage; and wherein the method comprises locating a field control element (100) in contact with an outer surface of the first part adjacent to the junction, and wherein the field control element is formed from a conducting material.