US-12626850-B2 - Housing part, electrical system and operating method

US12626850B2US 12626850 B2US12626850 B2US 12626850B2US-12626850-B2

Abstract

A housing part is configured to be connected to an electric component, to house an electric line, and to be filled with a liquid. The housing part includes an electrically conductive material and has an open mounting side to be connected to the electric component. A surface-to-volume ratio of the housing part is at least 3 m-1, and a ratio of the volume and a wall rupture pressure of the housing part is at least 0.02 m3MPa-1. A corresponding electric system is operated so that, when an electric arc occurs in the housing part, the housing part absorbs a pressure rise that is led into a component tank.

Inventors

Samuel Brodeur
Mattias Viksten
Glenn Stromberg
John Richard Tillery
Joakim Johansson

Assignees

HITACHI ENERGY LTD

Dates

Publication Date: 20260512
Application Date: 20210908
Priority Date: 20200918

Claims (20)

1 . A housing part, configured to be connected to an electric component, configured to house an electric line, and configured to be filled with a liquid, wherein the housing part comprises an electrically conductive material, wherein the housing part has an open mounting side to be connected to the electric component, a surface-to-volume ratio of the housing part being at least 3 m −1 and is at most 9 m −1 , and a ratio of a volume and a wall rupture pressure of the housing part being: between 0.04 m 3 MPa −1 and 0.6 m 3 Mpa −1 inclusive if the housing part is a straight turret, between 0.4 m 3 MPa −1 and 1.5 m 3 MPa −1 inclusive if the housing part is an external or a side turret, between 0.1 m 3 MPa −1 and 1 m 3 MPa −1 inclusive if the housing part is a cable box.
2 . The housing part of claim 1 , formed as one of a straight turret and an external turret, the housing part configured to be added to a transformer or to a shunt reactor as the electric component.
3 . The housing part of claim 1 , wherein the housing part comprises a top side and a side wall configured to the top side and the open mounting side, wherein the side wall is of a metal having a modulus of elasticity of at least 150 GPa at room temperature, and wherein a wall thickness of the side wall is at least 6 mm.
4 . The housing part of claim 3 , wherein the side wall is composed of at least two elements, said at least two elements being connected by at least two intermediate flanges located along the side wall between the top side and the open mounting side, and wherein the at least two intermediate flanges mechanically strengthen the side wall.
5 . The housing part of claim 1 , wherein a diameter (D) and a length (L) of housing part are between 0.3 m and 7 m inclusive, wherein a volume of a component tank is between 12 m 3 and 170 m 3 inclusive, and wherein the liquid that fills the housing part is transformer oil.
6 . The housing part of claim 1 , wherein the housing part further comprises a bottom flange surrounding the open mounting side, wherein the housing part is configured to be mounted to a component tank by means of the bottom flange.
7 . The housing part of claim 1 , wherein the housing part further comprises a top flange on a side of a side wall remote from the open mounting side, wherein a cover of the housing part that forms the top side comprises a cover flange, wherein the cover is fastened to the side wall by means of the top flange and the cover flange, wherein the cover comprises a lead-through opening, and wherein the electric line is fed into the housing part through the lead-through opening.
8 . An electric system, comprising: a housing part, configured to be connected to an electric component, configured to house an electric line, and configured to be filled with a liquid, wherein the housing part comprises an electrically conductive material, wherein the housing part has an open mounting side to be connected to the electric component, a surface-to-volume ratio of the housing part being at least 3 m −1 and is at most 9 m −1 , and a ratio of a volume and a wall rupture pressure of the housing part being: between 0.04 m 3 MPa −1 and 0.6 m 3 Mpa −1 inclusive if the housing part is a straight turret, between 0.4 m 3 MPa −1 and 1.5 m 3 MPa −1 inclusive if the housing part is an external or a side turret, between 0.1 m 3 MPa −1 and 1 m 3 MPa −1 inclusive if the housing part is a cable box; and an electric component having a component tank, wherein the housing part is mounted to the component tank by the open mounting side so that an interior of the component tank is connected with an interior of the housing part at the open mounting side, and wherein a volume of the component tank exceeds the volume of the housing part by at least a factor of 3.
9 . The electric system of claim 8 , wherein the housing part comprises a top side opposite the open mounting side and a side wall connecting the top side and the open mounting side, wherein the side wall is of a metal having a modulus of elasticity of at least 150 GPa at room temperature, and wherein a wall thickness of the side wall is at least 6 mm.
10 . The electric system of claim 9 , wherein the side wall is composed of at least two elements, said at least two elements being connected by means of at least two intermediate flanges located along the side wall between the top side and the open mounting side, and wherein the at least two intermediate flanges mechanically strengthen the side wall.
11 . The electric system according to claim 10 , wherein a bushing comprises a shield that clutches an end of the electric line, wherein at least one of the at least two intermediate flanges runs around at least one of the bushing and the shield on an exterior face of the side wall.
12 . The electric system according to claim 10 , wherein at least one of the at least two intermediate flanges, a bottom flange and the component tank, and the top flange and a cover flange are flanged together with a tightening torque of at least 1 kNm, and wherein at least one of a ratio of a thickness of the at least two intermediate flanges and the wall thickness of the side wall, a ratio of a thickness of the top flange and the wall thickness of the side wall, a ratio of a thickness of the bottom flange and the wall thickness of the side wall, and a ratio of a thickness of the cover flange and the wall thickness of the side wall is at least 5.
13 . The electric system according to claim 9 , wherein the housing part further comprises a top flange on a side of the side wall remote from the open mounting side, wherein a cover of the housing part that forms the top side comprises a cover flange, wherein the cover is fastened to the side wall by means of the top flange and the cover flange, wherein the cover comprises a lead-through opening, the electric line is fed into the housing part through the lead-through opening.
14 . The electric system according to claim 8 , wherein the electric component is a high-power transformer or a shunt reactor, wherein the housing part houses the electric line that is connected to a bushing of the electric component.
15 . The electric system according to claim 14 , wherein the bushing protrudes the component tank and terminates within the housing part.
16 . The electric system according to claim 8 , wherein a diameter (D) and a length (L) of the housing part are between 0.3 m and 7 m inclusive, wherein the volume of the component tank is between 12 m 3 and 170 m 3 inclusive, and wherein the liquid that fills the housing part and also the component tank is transformer oil.
17 . The electric system according to claim 8 , wherein the housing part further comprises a bottom flange surrounding the open mounting side, wherein the housing part is mounted to the component tank by means of the bottom flange.
18 . An operating method for an electric system comprising: a housing part, configured to be connected to an electric component, configured to house an electric line, and configured to be filled with a liquid, wherein the housing part comprises an electrically conductive material, wherein the housing part has an open mounting side to be connected to the electric component, a surface-to-volume ratio of the housing part being at least 3 m −1 and is at most 9 m −1 , and a ratio of a volume and a wall rupture pressure of the housing part being: between 0.04 m 3 MPa −1 and 0.6 m 3 Mpa −1 inclusive if the housing part is a straight turret, between 0.4 m 3 MPa −1 and 1.5 m 3 MPa −1 inclusive if the housing part is an external or a side turret, between 0.1 m 3 MPa −1 and 1 m 3 MPa −1 inclusive if the housing part is a cable box; and an electric component having a component tank, the housing part being mounted to the component tank by the open mounting side so that an interior of the component tank is connected with an interior of the housing part at the open mounting side, and wherein a volume of the component tank exceeds the volume of the housing part by at least a factor of 3, the method comprising: absorbing a pressure rise due to an electric arc occurring in the housing part; leading the pressure rise from the housing part into the component tank through the open mounting side; and deforming the component tank upon receiving the pressure rise to contain the pressure rise.
19 . The method according to claim 18 , wherein a travelling time of the pressure rise from a location of the electric arc to the open mounting side within the housing part is smaller than a full build-up time of the pressure rise.
20 . The method according to claim 18 , wherein the electric arc occurs at a bushing, at a shield and/or at a cable.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a 35 U.S.C. § 371 national stage application of PCT International Application No. PCT/EP2021/074671 filed on Sep. 8, 2021, which in turn claims foreign priority to Chinese Application No. 202010987942.9, filed on Sep. 18, 2020, also which in turn claims foreign priority to Chinese Application No. 202022057262.5, filed on Sep. 18, 2020 the disclosures and content of which are incorporated by reference herein in their entirety. TECHNICAL FIELD A housing part for an electrical system and such an electrical system are provided. Further, an operating method for such an electrical system is also provided. BACKGROUND Electric arcs may occur within electrical systems, such as transformers. Electric arcs occurring within a housing part of an electrical system may cause pressure to increase therein, potentially damaging the housing part and other components. SUMMARY An object to be achieved is to provide a housing part that can resist the pressures resulting from electric arcs occurring therein. This object may be achieved, inter alia, by a housing part, by an electrical system and by an operating method as specified in the independent claims. Exemplary further developments constitute the subject matter of the dependent claims. For example, the housing part is filled with transformer oil and is mechanically strengthened in such a way that a pressure rise due to an electric arc is absorbed and led into a greater component to that the pressure rise is deflected by the housing part, before the pressure rise can cause rupture or significant leakage of the housing part. Thus, damage to the housing part and also to surrounding equipment, for example, caused by fire due to rupture or leakage of the housing part, can be prevented. In at least one embodiment, the housing part is configured to be connected to an electric component, like a transformer or a shunt reactor, and is configured to house an electric line. Moreover, the housing part is configured to be filled with a liquid, wherein the housing part comprises an electrically conductive material. The housing part has an open mounting side to be connected to the electric component. A surface-to-volume ratio of the housing part is at least 3 m−1, and a ratio of the volume and a wall rupture pressure of the housing part is at least 0.02 m3 MPa−1. For example, the housing part is a turret to be mounted on a transformer or shunt reactor. The liquid may be a transformer oil configured to provide more efficient cooling than air. The electrically conductive material may be at least one metal, for example steel, like stainless steel. The open mounting side is, for example, a bottom side of a cylinder that forms the housing part. Accordingly, at the open mounting side the housing part comprises an aperture so that the mounting side is, for example, to at least 60% or 80% or 90% free of any solid material. Remaining areas of the mounting side may be formed of a material to rest on the electric component on which the housing part is mounted. The open mounting side may be of plain fashion so that the housing part can rest on an even surface of the electric component. Otherwise, the open mounting side may comprise a structuring to improve connectivity with the electric component. Such a structuring may be formed, for example, by an indentation, by an adaptor or by a fit ring. The surface-to-volume ratio of the housing part is comparably large. Thus, the surface-to-volume ratio could be at least 3 m−1 or at least 4 m−1 or at least 5 m−1. As an option, the surface-to-volume ratio may be at most 9 m−1 or at most 10 m−1 or at most 11 m−1. The surface of the housing part relevant to determine the surface-to-volume ratio may be an interior surface of the housing part excluding an area of the opening in the mounting side, or the relevant surface may also be an exterior surface of the housing part, again not taking into account the area of the opening in the mounting side. For example, if the housing part has the shape of a hollow cylinder, the relevant surface is an area of a cylinder barrel plus an area of a top side of the cylinder, assuming that a bottom side of the cylinder is completely open; when the cylinder has a height H and a radius R, then in this case the relevant surface is 2□RH+□R2. In another example, the housing part has the shape of a cuboid with a height H and a width W and a length K, then the relevant surface is 2H(L+K)+KL, again assuming that a bottom side of the cuboid is completely open. Further assuming that a wall thickness of the housing part is small compared with its diameter, it is noted that the exterior surface and the interior surface of the housing part are approximately the same. ‘Small compare with’ can mean that there is a at least a factor of 50 or 100 between the wall thickness and the diameter. If the housing part is not of round fashion, the diameter may be calculated as the square root of fou