Power device comprising an insulation gas for use in an electric energy power arrangement

Abstract

A power device includes a gas chamber adapted to include an insulation gas under a set of use conditions including a predetermined installation pressure, and an insulation component including a material in which said insulation gas is soluble and being arranged in relation to said gas chamber so as to be at least partly exposed to said insulation gas when the power device is in said use state. The power device has a delivery state, being a state of said power device before and/or at an installation time at which the power device is installed in said electric energy power arrangement under said set of use conditions including said installation pressure of said insulation gas in said gas chamber, wherein, in said delivery state, said insulation component includes an amount of pre-filled insulation gas which is dissolved in the material of the insulation component.

Claims

1. A power device for use in an electric energy power arrangement, said power device comprising: a gas chamber, wherein said gas chamber is adapted to, when in a use state in said electric energy power arrangement, contain an insulation gas therein under a set of use conditions, said set of use conditions comprising a use pressure, and at an installation time at a beginning of the use state the use pressure comprises a predetermined installation pressure of said insulation gas in said gas chamber; and an insulation component comprising a polymer material in which at least some of said insulation gas is soluble, wherein said insulation component is arranged in relation to said gas chamber so as to be at least partly exposed to said insulation gas when the power device is in said use state, wherein at a delivery time, said power device having a delivery state, being a state of said power device before the installation time at which the power device is installed in said electric energy power arrangement, wherein, in said delivery state, said insulation component comprises a pre-filled amount of the insulation gas being dissolved in the polymer material of the insulation component under a set of predetermined gas dissolving conditions for at least a predetermined gas dissolving time period before the delivery time, wherein said predetermined gas dissolving conditions comprise a predetermined gas dissolving pressure being greater than said predetermined installation pressure, wherein when the power device is in said delivery state, said gas chamber comprises said insulation gas under a set of delivery conditions, wherein said set of delivery conditions comprises a delivery pressure, said delivery pressure being lower than said installation pressure, and wherein said set of predetermined gas dissolving conditions and said predetermined gas dissolving time period is such that the insulation component comprises the pre-filled amount of the insulation gas being such that the use pressure of the insulation gas in said gas chamber follows a generally linear decay from said installation pressure at the installation time, when subject to said use conditions, proportional to the time elapsed from said installation time.

2. The power device according to claim 1, wherein said generally linear decay is such that, using a first pressure difference being a difference between said predetermined installation pressure and a first pressure value representative of a first pressure of the use pressure in said gas chamber at a first time after said installation time, and a second pressure difference being a difference between said first pressure value and a second pressure value, said second pressure value being representative of a second pressure of the use pressure in said gas chamber at a second time after the installation time, the second time after the first time, wherein a first time difference between the first time and the installation time is equal to a second time difference between the second time and the first time, and wherein said second pressure difference deviates by less than 10% from said first pressure difference.

3. The power device according to claim 2, wherein said first pressure value is a first average value as determined over a first predetermined measurement time range so as to be representative of the use pressure in the gas chamber at said first time, and/or wherein said second pressure value is a second average value as determined over a first predetermined measurement time range so as to be representative of the use pressure in the gas chamber at said second time.

4. The power device according to claim 2, wherein the first time difference is at least 5 days.

5. The power device according to claim 1, wherein said insulation gas comprises SF6 gas, CO2 gas, O2 gas and/or N2 gas.

6. The power device according to claim 1, said insulation gas comprises CO2 gas.

7. The power device according to claim 1, wherein said polymer material is an epoxy material.

8. A method for arranging a power device according to claim 1, comprising, installing said power device in an electrical energy power arrangement adapted to be operated at said set of use conditions.

9. An electric energy power arrangement, comprising one or more power devices, out of which each of at least one of the one or more power devices is in accordance with claim 1.

10. A method for manufacturing a power device for subsequent installation in an electric energy power arrangement, the power device comprising: a gas chamber, wherein said gas chamber is adapted to, when in a use state in said electric energy power arrangement, contain an insulation gas therein under a set of use conditions, the set of use conditions comprise a use pressure, and at an installation time at a beginning of the use state said use pressure comprises a predetermined installation pressure of said insulation gas in said gas chamber; and an insulation component being arranged in relation to said gas chamber so as to be at least partly exposed to said insulation gas when the power device is in said use state, said insulation component comprising a polymer material in which at least some of said insulation gas is soluble, and the method comprising the step of: prior to installing said power device in said use state, subjecting said insulation component to said insulation gas under a set of predetermined gas dissolving conditions for at least a predetermined gas dissolving time period, wherein said predetermined gas dissolving conditions comprise a predetermined gas dissolving pressure being greater than said predetermined installation pressure, such that said insulation component is prefilled with an amount of said insulation gas being dissolved in the polymer material of the insulation component, and wherein said set of predetermined gas dissolving conditions and said predetermined gas dissolving time period is such that the insulation component is pre-filled with said amount of said insulation gas being such that the use pressure of the insulation gas in said gas chamber follows a generally linear decay from said predetermined installation pressure at an installation time, when subject to said set of use conditions.

11. The method according to claim 10, further comprising forming said power device that comprises said insulation component before said step of subjecting said insulation component to said insulation gas under the set of predetermined gas dissolving conditions for said at least said predetermined gas dissolving time period.

12. The method according to claim 10, wherein said step of subjecting the insulation component to said insulation gas under said set of predetermined gas dissolving conditions for said at least said at least said predetermined gas dissolving time period is performed with the insulation component being comprised in said power device and comprises: filling said gas chamber with said insulation gas and maintaining said insulation gas in said gas chamber under said set of predetermined gas dissolving conditions of said power device for said at least said predetermined gas dissolving time period, so as to form said power device being in a delivery state before said use state wherein said insulation component comprises an amount of the pre-filled of said insulation gas being dissolved in the polymer material of the insulation component before connection to the electric energy power arrangement.

13. The method according to claim 10, wherein said set of predetermined gas dissolving conditions further comprises a predetermined gas dissolving temperature.

14. The method according to claim 13, wherein said set of use conditions further comprises a predetermined use temperature range and said predetermined gas dissolving temperature is higher than said predetermined use temperature range.

15. The method according to claim 10, comprising the step of, after said at least said predetermined gas dissolving time period, setting said power device to a set of predetermined storage conditions.

16. The method according to claim 15, wherein the set of predetermined storage conditions comprises a storage pressure being less than said predetermined gas dissolving pressure.

17. The method according to claim 15, wherein the set of predetermined storage conditions comprises a storage pressure being less than said predetermined installation pressure.

18. The method according to claim 10, wherein said insulation gas comprises CO2 gas.

19. The method according to claim 10, wherein said polymer material is an epoxy material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With reference to the appended drawings, below follows a more detailed description of embodiments of the disclosure cited as examples.

(2) In the Drawings:

(3) FIG. 1 of is a schematic view of a power device according to an example embodiment of the first aspect the disclosure;

(4) FIG. 2 is a schematical view of the power device of FIG. 1 as arranged in an electric energy power arrangement;

(5) FIG. 3 is a schematical view of an electric energy power arrangement comprising a plurality of power devices;

(6) FIG. 4 is a schematical method scheme illustrating an example embodiment of the second aspect of the disclosure;

(7) FIG. 5 is a schematical view of a power device according to another example embodiment of the first aspect of the disclosure;

(8) FIG. 6a is a chart illustrating the insulation gas pressure decline in a prior art power device in an electric energy power arrangement; and

(9) FIG. 6b is a chart illustrating the insulation gas pressure decline in a power device according to the first aspect of the disclosure.

DETAILED DESCRIPTION

(10) FIG. 1 depicts a schematic cross-sectional view of a power device 1 according to an example embodiment of the disclosure. The example power device 1 comprises an outer housing 50 forming a gas chamber 10 which, when the power device 1 is in use, will be filled with an insulation gas. The power device 1 of FIG. 1 further comprises a pair of conductors, each conductor being arranged in a sleeve forming an insulating component 20 of the power device 1. It is to be understood that the power device 1 is purely schematic and intended only to illustrated the concept of a power device 1 comprising a gas chamber 10 and an insulation component 20. Accordingly, FIG. 1 does not include any details such as power connections etc. of the device 1. As such, the power device 1 may be any kind of power device which is intended to be filled with an insulation gas during use. Thus, the power device 1 may be any device used for gas-insulated switchgear applications. For example, the power device 1 may be any one out of a transformer, capacitor, surge arrestor, breaker or disconnector.

(11) In the schematic illustration of FIG. 1, the power device 1 comprises a housing 50 forming the inner wall of the gas chamber 10, and the insulation components 20 are arranged inside the housing 50.

(12) As such, the housing 50 may be made by any suitable material, for example metal. However, in other applications, such as will be described in the below with reference to FIG. 5, the housing 50 may per se be an insulation component 20, and thus made by an insulating material.

(13) Further, the housing 50 of the power device 1 may be provided with one or more ports 55 to the gas chamber 10. One such port 55 may be adapted for filling the gas chamber 10 with insulation gas.

(14) Further, as is known in the art, the power device 1 may be adapted to be connectable to other power devices 1, 1 also comprising gas chambers 10, 10 as schematically illustrated in FIG. 3, in such a manner that the respective gas chambers 10, 10, 10 of the interconnected power devices 1 are in fluid communication with each other, as schematically illustrated in FIG. 2. To this end, the one or more of the one or more ports 55 may be arranged to be connectable to another power device 1.

(15) In use, the power device 1 is to be arranged in an electric energy power arrangement for high voltage environments. Examples of electric energy power arrangements may be switchgear arrangements, live tank breakers and/or dead tank breakers.

(16) FIG. 5 schematically illustrates another example of a power device 1 for use in an electric energy power arrangement.

(17) As exemplified in FIG. 5, the power device 1 may be a circuit breaker, i.e. an automatically operated electrical switch designed to protect an electrical circuit from damage due to an overcurrent caused by a fault. The power device 1 comprises an interrupter unit 62, which in the example embodiment includes a fixed contact 63a and a movable contact 63b arranged to be movable in relation to the fixed contact between an opened and a closed position. The power device 1 may further comprise an operating mechanism 72 arranged to operate the interrupter unit, i.e. to in the illustrated example move the moveable contact 63b between the opened and closed position by means of a movable arm 28. An insulating component 20 forms an insulating housing enclosing the interrupter unit 62. The insulating component 20 forms a gas chamber 10 which comprises insulation gas. The circuit breaker may further comprise a second insulating component forming a continuation of the insulating housing, for example a second insulating component arranged below the illustrated insulating component and arranged to house power and ground contacts.

(18) As such, the power device 1 illustrated in FIG. 5 is an example of a power device 1 wherein the insulating component 20 forms at least part of the inner wall of the gas chamber 10.

(19) In use, a power device 1 such as those exemplified in the above, is used in an electric energy power arrangement 100. As such, the gas chamber 10 of the power device 1 is adapted to, when in a use set in the power arrangement 100, comprise an insulation gas under a set of use conditions. The use conditions comprise a predetermined installation pressure, being the pressure of the gas in the gas chamber 10 which is set when introducing the gas into the gas chamber.

(20) The insulating gas may be any gas suitable for the application. As such, the gas may for example be SF6 gas, CO2 gas, O2 gas and/or N2 gas.

(21) The insulating component 20 may be made by an insulating material suitable for the application. Suitable insulating materials may for example be a polymer material, such as an epoxy material.

(22) Power devices 1 and electric energy power arrangements 100 such as those generally described in the above are already known in the art. However, and as intimated in the introduction of the application, prior art power devices may suffer from that the pressure in the gas chamber 10, which is initially set to a desired use pressure being equal to the installation pressure of the gas at installation of the electric energy power arrangement 100, declines with time.

(23) FIG. 6a illustrate schematically the decline in the pressure in the gas chamber 10 of a power device 1, in this example being a breaker, after an installation time to. As seen in FIG. 6a, during a first time period after the installation time to, the pressure of the insulation gas drops from the installation pressure P0 relatively swiftly, with the pressure decay generally following an exponential curve. After this first time period after the installation time to, the pressure decay rate slows down such that the pressure decay follows a generally linear curve. This pressure decay as exhibited by prior art power devices results eventually in that the pressure in the gas chamber reaches an unacceptably low level. To remedy or to prevent this, it is therefore standard practice to refill the power device with additional gas so as to reassume the installation pressure P0 after some time of operation of the power device. For example, such refill may be planned to take place e.g. 3 to 4 years after installation.

(24) With the power device 1 as proposed herein, the insulation component 20 is pre-filled with dissolved insulation gas prior to the installation of the power device 1 in a power arrangement 100 at the installation time to, at which the gas chamber 10 is set to comprise insulation gas at the desired installation pressure P0.

(25) As proposed herein, when the insulation component 20 comprises a material in which the insulation gas is soluble, the insulation component 20 may be pre-filled with dissolved insulation gas.

(26) Accordingly, there is provided a power device 1 having a delivery state, being a state of the power device 1 before and/or at an installation time to at which the power device is installed in the electric energy power arrangement 100 under a set of use conditions comprising the installation pressure P0 of the insulation gas in the gas chamber. As proposed herein, the insulation component 20 is pre-filled with dissolved insulation gas when in the delivery state.

(27) The power device 1 in its delivery state, i.e. the power device for subsequent installation in an electric energy power arrangement may be manufactured by a method comprising the step of: Subjecting the insulation component 20 to the insulation gas under a set of predetermined gas dissolving conditions for at least a predetermined gas dissolving time period S10, such that the insulation component 20 is prefilled with dissolved insulation gas.

(28) The predetermined gas dissolving conditions comprise a predetermined gas dissolving pressure being greater than the installation pressure P0.

(29) It has been found by the inventors, that the initial, exponential pressure drop in the pressure chamber 10 as illustrated in FIG. 6a is primarily due to the insulation gas dissolving into the insulation component 20 of the power device 1. Hence, by providing a power device 1 in a delivery state wherein the insulation component 20 is prefilled with dissolved insulation gas, the pressure in the gas chamber 10 of such a power device 1 after the installation time to may be generally linear, as exemplified in FIG. 6b.

(30) FIG. 6b illustrates as FIG. 6a schematically the decline in the pressure in the gas chamber 10 of a power device 1, in this example being a breaker, after an installation time to at which a desired installation pressure P0 is set up in the insulation gas of the insulation chamber 10 of a power device 1. In FIG. 6b however, the insulation component 20 is pre-filled with dissolved insulation gas. Hence, the decline in the pressure in FIG. 6b is a generally linear decline. It will be understood that by thus avoiding the exponential drop in pressure which may be seen in FIG. 6a, the refill of the power device 1 with additional gas so as to reassume the installation pressure P0 after some time of operation of the power device 1 may be considerably postponed as compared to the prior art device, or the need for refill may be completely removed.

(31) As mentioned in the above, the method comprises subjecting the insulation component 20 to the insulation gas under a set of predetermined gas dissolving conditions for at least a predetermined gas dissolving time period. The predetermined gas dissolving conditions and the predetermined gas dissolving time period may be determined so as to arrive at a desired insulation component 20 being pre-filled with dissolved insulation gas.

(32) In particular, the predetermined gas dissolving conditions may be set so as to promote gas dissolving into the insulation component 20 at a higher rate per time unit than what would be the case under normal use conditions of the power device.

(33) To this end, the predetermined gas dissolving pressure may be greater than the installation pressure P0.

(34) Also, the predetermined gas dissolving conditions may comprise a predetermined gas dissolving temperature, being higher than an intended use temperature range of the power device 1.

(35) The predetermined gas dissolving conditions and the predetermined gas dissolving time suitable for a power device may be empirically determined for a specific power device. For example, parameters such as the volume of the insulating member, the volume of the insulation chamber, the material of the insulating member and the type of insulation gas may be relevant for the result.

(36) For example, in a power breaker, wherein the insulation component comprised glass fiber reinforced epoxy and where the insulation gas was CO2, the method was performed with a predetermined gas dissolving promoting pressure of 11.2 bar and a predetermined gas dissolving promoting time of 3 months. The temperature was 22 degrees Celsius. The volume of CO2 gas in the power breaker was 3.52 I, the area of the glass fiber reinforced epoxy was 0.175 m2, and the thickness of the glass fiber reinforced epoxy was 0.0065 m. The result of the method was a power breaker which, when set under use conditions displayed a linear gas pressure decay as described in the above.

(37) The predetermined gas dissolving promoting time may be dependent on factors such as the geometry of the insulation component. Generally, the predetermined gas dissolving promoting time may be shorted by using a higher predetermined gas dissolving promoting pressure and/or a higher temperature.

(38) As set out in the above, the method may be performed such that the insulation component is pre-filled with insulation gas to such a degree that the pressure of the insulation gas in the gas chamber 10 follows a generally linear decay from the installation pressure P0 at the installation time, when subject to the use conditions.

(39) To determine whether the power device 1 comprising a pre-filled insulation component 20 displays a generally linear decay from the installation pressure P0, the power device 1 comprising the pre-filled insulation component 20 in a delivery state is hence set up under the intended use conditions. The installation time to is the initial time at which the use conditions, including the installation pressure P0 of the insulation gas, is set up for the power device 1. Then, the power device 1 is left without any adjustment to the pressure in the gas chamber 10 for some time, while the pressure in the chamber may be measured.

(40) To determine whether the pressure decay in the gas chamber 10 after the installation time to is generally linear, different methods may be applied.

(41) For example, with reference to FIG. 6b, a first pressure value P1 representative of the pressure in the gas chamber 10 at a first instant t1 being a selected time range delta t from the installation time to is measured. Then, a second pressure value P2 representative of the pressure in the gas chamber 10 at a second time instant t2 being two subsequent of the selected time ranges delta t, from the installation time to.

(42) A first pressure difference deltaP1 being the difference between the installation pressure P0 and the first pressure value P1 is determined, and a second pressure difference deltaP2, being the difference between the first pressure value P1 and the second pressure value P2 is determined. If the second pressure difference deltaP2 deviates by less than 10% from the first pressure difference deltaP1, the pressure decay may be determined to be generally linear.

(43) The time range to the first time instant may be selected to be relevant for the power device and its use conditions. For example, the first time instant may be at least 5 days from the installation time to. For example, the first time instant may be 5 days.

(44) The first and/or second pressure values may be average values as determined over a predetermined measurement time range so as to be representative of the pressure in the gas chamber 10 at the first or second time instant.

(45) The method as set out in the above may be performed prior to that the insulation component 20 is arranged in the power device 1.

(46) However, alternatively, and as illustrated in the example method of FIG. 4, the method step S10 may be performed with the insulation component 20 being comprised in the power device 1. Thus, the method step S10 may comprise filling the gas chamber 10 with the insulation gas S11 and maintaining the insulation gas in the chamber 10 under the set of predetermined gas dissolving conditions of the power device 1 for at least the predetermined gas dissolving time period S12, so as to form the power device 1 being in a delivery state wherein the insulation component 20 is pre-filled with dissolved insulation gas before connection to a power arrangement 100.

(47) Further, the method may comprise, after the predetermined gas dissolving time period, setting the power device to a set of predetermined storage conditions S20. The set of storage conditions may for example comprise a storage pressure being less than the predetermine gas dissolving pressure and less than the predetermined installation pressure.

(48) The method may comprise the step of closing the gas chamber 10 using a removable closure 40 so as to maintain the insulation gas in the chamber in the delivery state of the power component S30. The closing of the gas chamber 10 may be performed after the above-mentioned step S20 of setting the power device to a set of predetermined storage conditions, as exemplified in FIG. 4.

(49) The steps S10 to S50 are thus involved in providing a power device in a delivery state prior to installing the power device in a power arrangement.

(50) In a method for arranging the power device in a power arrangement, the method may further comprise a step S40 of storing and/or transporting the power device 1 including the removable closure 40, and a step S50 removing the removable closure 40 before installing the power device 1 in a power arrangement 100.

(51) With a following step S60 of installing the power device in an electrical energy power arrangement adapted to be operated at the use conditions, the electrical energy power arrangement 100 is formed.

(52) It is to be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.