HOUSING PART, ELECTRICAL SYSTEM AND OPERATING METHOD

Abstract

In at least one embodiment, the 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 comprises 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.

Claims

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.sup.−1 and is at most 9 m.sup.−1, and a ratio of the volume and a wall rupture pressure of the housing part being: between 0.04 m.sup.3 MPa.sup.−1 and 0.6 m.sup.3Mpa.sup.−1 inclusive if the housing part is a straight turret, between 0.4 m.sup.3 MPa.sup.−1 and 1.5 m.sup.3 MPa.sup.−1 inclusive if the housing part is an external or a side turret, between 0.1 m.sup.3 MPa.sup.−1 and 1 m.sup.3 MPa.sup.−1 inclusive if the housing part is a cable box.

2. The housing part of claim 1, formed as a turret and configured to be added to a transformer or to a shunt reactor as the electric device.

3. 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.sup.−1 and is at most 9 m.sup.−1, and a ratio of the volume and a wall rupture pressure of the housing part being: between 0.04 m.sup.3 MPa.sup.−1 and 0.6 m.sup.3Mpa.sup.−1 inclusive if the housing part is a straight turret, between 0.4 m.sup.3 MPa.sup.−1 and 1.5 m.sup.3 MPa.sup.−1 inclusive if the housing part is an external or a side turret, between 0.1 m.sup.3 MPa.sup.−1 and 1 m.sup.3 MPa.sup.−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.

4. The electric system of claim 3, 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.

5. The electric system of claim 4, wherein the side wall is composed of at least two elements, said 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 intermediate flanges mechanically strengthen the side wall.

6. The electric system according to claim 3, 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.

7. The electric system according to claim 1, wherein the bushing protrudes the component tank and terminates within the housing part.

8. The electric system according to claim 5, wherein the bushing comprises a shield that clutches an end of the electric line, wherein at least one of the intermediate flanges runs around at least one of the bushing and the shield on an exterior face of the side wall.

9. The electric system according to claim 3, wherein a diameter (D) and a length (L) of housing part are between 0.3 m and 7 m inclusive, wherein the volume of the component tank is between 12 m.sup.3 and 170 m.sup.3 inclusive, and wherein the liquid that fills the housing part and also the component tank is transformer oil.

10. The electric system according to claim 3, 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.

11. The electric system according to claim 3, 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.

12. The electric system according to claim 5, wherein at least one of the intermediate flanges, the bottom flange and the component tank, and the top flange and the 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 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. 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.sup.−1 and is at most 9 m.sup.−1, and a ratio of the volume and a wall rupture pressure of the housing part being: between 0.04 m.sup.3 MPa.sup.−1 and 0.6 m.sup.3Mpa.sup.−1 inclusive if the housing part is a straight turret, between 0.4 m.sup.3 MPa.sup.−1 and 1.5 m.sup.3 MPa.sup.−1 inclusive if the housing part is an external or a side turret, between 0.1 m.sup.3 MPa.sup.−1 and 1 m.sup.3 MPa.sup.−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.

14. The method according to claim 13, 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.

15. The method according to claim 13, wherein the electric arc occurs at the bushing, the shield and/or at the cable.

16. 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.

17. The housing part of claim 16, wherein the side wall is composed of at least two elements, said 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 intermediate flanges mechanically strengthen the side wall.

18. 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 the volume of the component tank is between 12 m.sup.3 and 170 m.sup.3 inclusive, and wherein the liquid that fills the housing part is transformer oil.

19. 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.

20. The housing part of claim 1, 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, and wherein the electric line is fed into the housing part through the lead-through opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In the Figures:

[0078] FIG. 1 is a schematic side view of an exemplary embodiment of an electric system described herein,

[0079] FIG. 2 is a schematic sectional view of the electric system of FIG. 1,

[0080] FIG. 3 is a detail of the schematic sectional view of the electric system of FIG. 2,

[0081] FIG. 4 is a schematic perspective view of a housing part of the electric system of FIG. 1,

[0082] FIG. 5 is a schematic sectional view of the housing part of FIG. 4,

[0083] FIG. 6 is a schematic perspective view of an exemplary embodiment of an electric system described herein,

[0084] FIG. 7 is a schematic sectional view of an exemplary embodiment of a housing part described herein,

[0085] FIGS. 8 to 10 are schematic side views of exemplary embodiments of an electric system described herein, and

[0086] FIGS. 11 and 12 are schematic representations of time vs. pressure dependencies in housing parts.

DETAILED DESCRIPTION

[0087] FIGS. 1 to 5 illustrate an exemplary embodiment of an electric system 100 comprising an exemplary embodiment of a housing part 1. The electric system 100 also comprises an electric component 2 that is, for example, a transformer 21 or, as an alternative, a shunt reactor. An electric line 3 is provided to the electric device 2 through the housing part 1. Hence, the housing part 1 may be a top turret 11 mounted on the electric component 2.

[0088] The electric component 2 comprises a component tank 6 in which a base element 62 is located, see FIG. 2. The component base element 62 includes, for example, transformer windings and a transformer core. Further, the electric component 2 comprises an interior line 61 by means of which current is fed to the component base element 62. For example, the component interior line 61 is a high-power line and is configured to carry high voltages. The component tank 6 as well as the housing part 1 are filled with a liquid 4, for example, a transformer oil.

[0089] As can be seen from FIGS. 2 and 3, the electric line 3 is connected to the component interior line 61 by means of a bushing 27, for example. At an end 31 of the electric line 3, optionally there is a shield 28 of the bushing 27 that clamps the electric line 3. Said shield 28 may be located in the middle or approximately in the middle of the housing part 1, seen along a direction perpendicular to an open mounting 51 side of the housing part 1. For example, the electric line 3 comprises an electrically conductive core 33 and an electric insulation 32 around the core 33 that runs up to the end 31.

[0090] In the region of the end 31, see FIG. 3, a distance between the bushing 27 of the shield 28 that are configured to carry current on the one hand, and the electrically conductive housing part 1 on the other hand, is comparably small. Thus, in this region there is the highest probability that an electric arc 8 may occur. Hence, the electric arc 8 may occur in a comparably narrow area of the housing part 1 and also within a relatively small volume defined by the housing part 1.

[0091] Because of the electric arc 8, the liquid 4 decomposes in the region of the arc 8 and a rapid pressure rise 7 occurs in the small volume in the housing part 1, compare also FIGS. 11 and 12 below. By means of the mechanically comparably strong housing part 1, the pressure rise 7 is deflected into a by far larger volume of the component tank 6. Hence, the pressure rise 7 can be absorbed in the component tank 6 and harm to the electric system 100, for example, due to fires resulting from a spill of the liquid 4 and of gases out of the housing part 1, can be prevented.

[0092] Accordingly, see FIGS. 4 and 5, the housing part 1 is constructed in a mechanically stable manner. However, attention has to be paid to ensure that the housing part 1 is not oversized concerning its mechanical properties in order to avoid too much mechanical load to the component tank 6 and in order to keep costs relatively low.

[0093] In this exemplary embodiment, the housing part 1 has, in principle, the shape of a hollow cylinder. A mounting side 51 of the housing part 1 facing the component tank 6 is essentially open, so that a diameter of an opening at the mounting side 51 corresponds to an inner diameter of the hollow cylinder. Hence, the opening at the mounting side 51 is as large as possible.

[0094] A top side 52 of the housing part 1 may be formed of a cover 57. As an option, atop the cover 57 there is a further element of the housing part 1 in order to mount the electric line 3. Thus, by means of the further element a lead-through opening 59 is defined at the top side 52.

[0095] The top side 52 and the open mounting side 51 are connected by a side wall 53. As an option, the side wall 53 is of multi-piece design so that the side wall 53 is composed of two elements 50. The elements 50 can be of the same design or can have different shapes. For example, the elements 50 of the side wall 53 are tubes having flanges 54, 55, 56 at their respective ends.

[0096] Thus, at the open mounting side 51 there is a bottom flange 55, at an interface between the elements 50 of the side wall 53 there are two intermediate flanges 54, and at the top side 52 there is a top flange 56 of the topmost element 50 of the side wall 53 and a cover flange 58 of the cover 57. All the flanges 54, 55, 56, 58 can be formed integrally with the respective elements 50, 57 and may constitute rings or rims at the end of the tubes that form the elements 50 of the side wall 53. The flanges 54, 55, 56, 58 may be connected by means of bolts 91 and by means of an O-ring 92 between each one of the elements 50, the cover 57 and the component tank 6. The O-rings 92 may be of a rubber or also of a metal.

[0097] As an option, the intermediate flanges 54 are located close to the end 31 of the electric line 3 and, thus, near the shield 58 of the bushing 57. Hence, the intermediate flanges 54 may serve as a mechanical strengthening of the side wall 53. Moreover, the probable electric arc position is relatively close to the open mounting side 51 so that the pressure rise 7 can be led into the larger component tank 6 within a short period of time.

[0098] The liquid 4 may fill, for example, 60% to 75% of a total internal volume of the housing part 1, the remaining space within the housing part 1 is occupied by the electric line 3, the bushing 27 and the component interior line 62. The same may apply to the component tank 6 relative to the component interior line 61 and the component base element 62.

[0099] Optionally, the following parameters apply to the housing part 1, individually or in any combination, for example, with a tolerance in each case of at most a factor of 1.5 or at most a factor of 1.3 or at most a factor of 1.1: [0100] A wall thickness of the tubes that constitute the elements 50 of the side wall 52 is 8 mm. [0101] The elements 50 of the side wall 53 and the cover 57 are made of a material having a Young's modulus of 200 GPa, for example, of steel of or stainless steel. [0102] The flanges 54, 55, 56 and/or 58 and, thus, the cover 57, have a thickness of 50 mm. For example, the flanges 54, 55, 56, 58 may be in accordance with ANSI B16.47 Class 150, or in accordance with a similar class. [0103] The bolts 91 are M36 bolts, for example, in accordance with ISO 898 Class 8.8. [0104] A tightening torque to the bolts 91 is 2400 Nm. [0105] A diameter of the elements 50 of the side wall 53, for example, an inner diameter, is 930 mm. [0106] A length of the housing part 1, for example, including the cover 57 but excluding the further element atop the cover 57, is 2.3 m.

[0107] Thus, the housing part 1 may have a surface-to-volume ratio of about 4.7 m.sup.−1, and a ratio of the volume and a wall rupture pressure r of the housing part 1 may be about 0.17 m.sup.3 MPa.sup.−1.

[0108] As an option, a valve 44 may also be present, for example, at the side wall 53 of the housing part 1. However, such a pressure relief valve 44 is typically too slow to allow the pressure rise 7 caused by the electric arc 8 to be relieved in time.

[0109] In FIG. 6, another exemplary embodiment of the system 100 is shown. The electric component 2 is, for example, a shunt reactor 22, but may also be a transformer 21, not shown.

[0110] There is a plurality of the housing parts 1 at a top side of the component tank 6. For example, there are three top turrets 11, each equipped with one electric line 3. Further, additionally or alternatively to the top turrets 11, there can be a cable box 13 as further housing part 1.

[0111] Otherwise, the same applies for FIG. 6 as for FIGS. 1 to 5.

[0112] In FIG. 7, an exemplary embodiment of the housing part 1 that is configured as a cable box 13 is illustrated. The cable box 13 may be of cuboid or of approximately cuboid shape, and may have an open mounting side 51 and a closed top side 52 as well as a closed side wall 53. Optionally, there are multiple electric insulations 32 and electric lines 3 within the cable box 13. For example, a surface-to-volume ratio of the cable box 13 is 2.4 m.sup.−1, and a ratio of the volume and a wall rupture pressure r of the cable box 13 is 1.1 m.sup.3 MPa.sup.−1.

[0113] Such a cable box 13 can be present in all the exemplary embodiments of the electric system 100.

[0114] Otherwise, the same applies for FIG. 7 as for FIGS. 1 to 6.

[0115] FIGS. 8 to 10 schematically illustrate further exemplary embodiments of the electric system 100 comprising exemplary housing parts 1.

[0116] According to FIG. 8, the housing part 1 is configured as a side turret 12 located at a side wall of the component tank 6. Such a side turret 12 can be present in all the exemplary embodiments of the electric system 100, for example, additionally or alternatively to the top turret 11. Otherwise, the same applies for FIG. 8 as for FIGS. 1 to 7.

[0117] According to FIG. 9, the housing part 1 is configured as a cable termination 15. For example, the cable termination 15 is located within the component tank 6, but could alternatively also be located at a side wall or at a top of the component tank 6. Such a cable termination 15 can be present in all the exemplary embodiments of the electric system 100. Otherwise, the same applies for FIG. 9 as for FIGS. 1 to 8.

[0118] According to FIG. 10, the housing part 1 is configured as an on-load tap charger 14. For example, the on-load tap charger 14 is located at a top of the component tank 6. Such an on-load tap charger 14 can be present in all the exemplary embodiments of the electric system 100. Otherwise, the same applies for FIG. as for FIGS. 1 to 9.

[0119] As in all other exemplary embodiments, the top side 52 and the side wall 53 may merge to be a single surface of the housing part. Optionally, as shown in FIG. 10, the top side 52 and the side wall 53 may be fashioned together as a dome, for example, as a hollow hemisphere.

[0120] In FIGS. 11 and 12, an exemplary pressure rise 7 is characterized. As illustrated in FIG. 11, the pressure rise 7 and the associated electric arc may build up on a time scale of about 40 ms. Hence, in a closed fixed volume a maximum pressure would occur not before 40 ms after the electric arc has initiated. In other words, in the volume of the turret alone, with no tank attached, the maximum pressure in the turret would occur after 40 ms; however, this duration will also depend on the actual arcing duration.

[0121] As can be seen from FIG. 12, a pressure P in the housing part 7 quickly rises and reaches a maximum on a time scale of 5 ms to 10 ms, and then declines. This comparably rapid decline is caused by the pressure release through the open mounting side 51 into the component tank 6.

[0122] The pressure rises 7 in FIG. 12 are caused by electric arcs having an energy of 20 MJ and 30 MJ, respectively. Such fast rising high-energy electric arcs exceeding energies of, for example, 15 MJ can otherwise be very destructive in high-voltage applications.

[0123] Based on the turret 11 of FIGS. 4 and 5, the housing part 1 has a wall rupture pressure r of 9 MPa. However, a leakage pressure I, at which minor and short-term leakage of the liquid 4 may occur in a region of the flanges 54, 55, 56, 58 in case of high-energetic electric arcs of more than 30 MJ, is lower and amounts to 4.6 MPa.

[0124] Hence, the housing part 1 in the electric system 100 described herein can withstand high-energetic electric arcs.

[0125] The disclosure described here is not restricted by the description given with reference to the exemplary embodiments. Rather, the disclosure encompasses any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or exemplary embodiments.

LIST OF REFERENCE SIGNS

[0126] 1 housing part [0127] 11 turret, top type [0128] 12 turret, side type [0129] 13 cable box [0130] 14 on-load tap charger [0131] cable termination [0132] 2 electric component [0133] 21 transformer [0134] 22 shunt reactor [0135] 27 bushing [0136] 28 shield of the bushing [0137] 3 electric line [0138] 31 end of the electric line [0139] 32 electric insulation [0140] 33 electrically conductive core [0141] 4 liquid [0142] 44 valve [0143] 50 element of the housing part [0144] 51 open mounting side [0145] 52 top side [0146] 53 side wall [0147] 54 intermediate flange [0148] 55 bottom flange [0149] 56 top flange [0150] 57 cover [0151] 58 cover flange [0152] 59 lead-through opening [0153] 6 component tank [0154] 61 component interior line [0155] 62 component base element [0156] 7 pressure rise [0157] 8 electric arc [0158] 91 bolt [0159] 92 O-ring [0160] 100 electric system [0161] D diameter of the housing part [0162] I leakage pressure [0163] L length of the housing part [0164] P pressure [0165] r wall rupture pressure [0166] t time