Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/14—Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/16—Impedances connected with contacts
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/14—Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc
  • H01H2033/146—Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc using capacitors, e.g. for the voltage division over the different switches
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/008—Pedestal mounted switch gear combinations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
  • H01H9/42—Impedances connected with contacts

Definitions

• the invention relates to a high-voltage switch having a switching assembly in a metal enclosure.
• the invention also relates to a method for operating such a switch.
• Circuit breakers for high-voltage applications typically may comprise a switching assembly having one or more electrical switches arranged in a metal enclosure.
• the metal enclosure is grounded, while the switching assembly is at high-voltage potential.
• the size of the metal enclosure must be in- creased in order to keep the field strengths within acceptable limits. This is expensive and requires different circuit breaker components for different voltage ratings.
• the switch comprises at least two metal enclosures, with a switching assembly arranged in each metal enclosure, wherein said switching assemblies are arranged in series and wherein said at least two metal enclosures are electrically insulated from each other.
• the two metal enclosures being electrically insu ⁇ lated from each other, and in particular being insulated from ground, allows arranging a plurality of metal- enclosed switching assemblies in series wile avoiding ex ⁇ cessive electrical fields in any of them.
• the high-voltage switch can comprise, for ex ⁇ ample, switching assemblies with high-voltage circuit breaking and/or high-voltage disconnecting function and/or high-voltage current commutating function.
• the high-voltage switch can be a high-voltage disconnector, a high-voltage circuit breaker, a high- voltage current commutating device, or similar devices.
• the switching assemblies are arranged in series such that a high voltage can be switched.
• Each switching assembly is arranged in a metal enclosure, with the metal enclosures being electrically insulated from each other. This allows to keep the metal enclosures at different electrical potentials and therefore to reduce the electrical fields within them. Hence, smaller metal enclosures can be used.
• the design is scalable in the sense that the same metal enclosure and switching assembly can be re ⁇ used for different voltage ratings. For comparatively small voltage ratings, a single enclosure and switching assembly can be used. For larger voltage ratings, two, three or even more switching assemblies can be arranged in series, with each being mounted in its metal enclosures and the metal enclosures being mutually insulated.
• the switch comprises a first metal enclosure enclosing a first switching assembly as well as a second metal enclosure enclosing a second switching assembly. Further, the switch comprises a first and a second terminal.
• the switching assemblies are arranged in series between the terminals, such that they can interrupt a current flow between the terminals.
• the first terminal is electrically connected to the first metal enclosure and a second terminal is electrically connected to the second enclosure.
• the switch comprises, for each switching assembly, at least one impedance device arranged in parallel to the switching assembly or are arranged between the metal enclosure and a node between the switching assemblies.
• the impedance devices can have matching impedances in order to evenly distribute the applied voltage over the switching assemblies and/or to compensate for a stray capacitance from the conductor to ground.
• the invention also relates to a method for operating the above switch.
• This method comprises the step of connecting a first one of the switching assemblies to a first high-voltage potential and a second one of the switching assemblies to a second high voltage potential in such a manner, that the switching assemblies are arranged in series between said first and said second potentials in order to interrupt the current flow between them.
• Fig. 1 shows a view of a switch
• Fig. 2 shows a sectional view of a switch
• Fig. 3 shows a switching assembly with several switches and/or switching gaps
• Fig. 4 shows a switch design with more than two switching assemblies, where the metal enclosures are held at intermediate potentials, and
• Fig. 5 shows a sectional view of a further embodiment of a switch.
• high voltage designates voltages typically exceeding 72 kV.
• a gas with elevated pressure designates an insulating gas having a pressure exceeding at ⁇ mospheric pressure, in particular exceeding 2 bars.
• Figs. 1 and 2 show switches having a first switching assembly la and a second switching assembly lb.
• First switching assembly la is arranged in a first metal enclosure 2a
• second switching assembly lb is ar ⁇ ranged in a second metal enclosure 2b.
• Each switching assembly comprises one or more electrical switching units 4.
• a suitable switching unit may for example be based on the concepts presented in US 7, 235, 751 B2.
• each metal enclosure is filled with an insulating medium, in particular with a gas of elevated pressure, such as SF S , for increasing the break ⁇ down voltage.
• a gas of elevated pressure such as SF S
• the two switching assemblies la, lb are arranged in series and are interconnected by means of a conductive rod 5.
• the two enclosures 2a, 2b are mechanically interconnected by means of an electrically insulat ⁇ ing cylinder 6, which encloses the conductor 5.
• Cylinder 6 can, for example, also be filled with an insulating gas of elevated pressure, such as SF e , for increasing the break-down voltage. Furthermore, it may or may not contain partitions in order to separate the total volume of gas or insulating medium into one or several gas zones.
• the switch can be arranged as a whole in ambient air in a so-called live tank configuration.
• the switch comprises two terminals 8a, 8b, for connecting it to a line 9 to be interrupted.
• the first and second switching assemblies la, lb are arranged in series between the first and the second terminals 8a, 8b. Further, in the present embodiment, first terminal 8a is electrically connected to first metal enclosure 2a and second terminal 8b is electrically connected to second metal enclosure 2b.
• the switchs of Figs. 1 and 2 further comprise a frame designated by numerals 10a - lOj . It has a first section 10a, 10b, 10c, a second section lOd, lOe, lOf and a third section lOg - lOj .
• First section 10a - 10c is mechanically connected to first metal enclosure 2a
• second section lOd - lOf is mechanically connected to second metal enclosure 2b
• third section lOg - lOj mechanically connects the first and second sections to each other.
• At least third section lOg - lOj is electrically in ⁇ sulating. For example, it comprises a plurality of rods lOg, lOh, lOi and lOj extending between the first and the second sections 10a - 10c and lOd - lOf, respectively.
• the switch comprises an electrically insulating suspension 12 for suspending the switch e.g. in a scaffolding 14.
• the suspension 12 com ⁇ prises several suspension members 12a - 12d, at least one of which is connected to first frame section 10a - 10c and at least another of which is connected to second frame section lOd - lOf.
• the whole switch can also be supported from the ground, e.g. by means of support insulators, rather than being suspended from a scaffolding 14.
• Each switching assembly comprises an actuator for actuating its switches.
• a first actuator 15a is attributed to the first switching assembly la. It is at the potential of the first enclosure 2a and it comprises one or several actuating coils 15a" and an energy storage 15a' .
• Energy storage 15a' is mounted to first frame section 10a - 10c and feeds actuating coil(s) 15a" mounted in the first enclosure 2a for operating the first switching assembly la.
• a second actuator 15b is attributed to the second switching assembly lb. It is at the potential of the second enclosure 2b and it comprises at least one actuating coil 15a" and an energy storage 15b' .
• Energy storage 15b' is mounted to second frame section lOd - lOf and feeds at least one actuating coil 15b" mounted in the second enclosure 2b for operating the second switching assembly lb.
• each actuator 15a, 15b is at the potential of the metal enclosure 2a, 2b of its switching assembly la, lb; i.e. preferably the voltage difference between each actuator 15a, 15b and its respective enclosure 2a, 2b is less than 5 kV. If the enclosure may contain a plurality of contact members la, lb, 4 as indicated below in Fig. 3, the actuator needs to be electrically insulated therefrom.
• the actuators 15a, 15b are electrically insulated from each other.
• each actuator 15a, 15b comprises its own power supply with a galvanically insulated power feeder 16a, 16b, respectively.
• a "galvanically insulated power feeder” is a feed for feeding electrical power from ground potential to an elevated high voltage potential.
• feeds are known to the skilled person and can e.g. consist of a plurality of coupling capacitors in series creating a capacitive circuit between ground and high voltage potential that can be supplied by a high frequency source at ground potential (see for example US 2006152199 Al) .
• Other such power feeders may be based, for example, on inductive, hydraulic, pneumatic or mechanical principles.
• the switch In operation, the switch is connected with its terminals 8a, 8b to a line 9 to be interrupted.
• the switching assemblies la, lb as well as conductive rod 5 are on the same high voltage potential.
• the metal enclosures 2a, 2b will also be on high voltage potential.
• the primary voltage drop of the system voltage to ground occurs over suspension 12 and power feeders 16a, 16b, which have been built for that purpose and are easily adapted to the respective voltage ratings.
• the switching assemblies la, lb When the switching assemblies la, lb are switched off, i.e. when they are in their non-conductive state, there will typically be a high-voltage drop over the terminals 8a, 8b.
• the potential on conductive rod 5, i.e. at the electrical node 17 between the switching assemblies la, lb, will depend primarily on the impedances over each switching assembly, i.e. on the impedances between node 17 and the two terminals 8a, 8b, respectively, but also on the impedance between the enclosures 2a and 2b as defined e.g. by the length of cyl ⁇ inder 6.
• impedances that affect the voltage distribution are the impedances of the terminals 8a, 8b to ground and of node 17 to ground.
• Three closed dashed lines 20 in Fig. 2 enclose the three major parts of the breaker that are electrically connected to each other and are therefore on the same potentials.
• an ex ⁇ emplary embodiment comprises auxiliary impedance devices 18a, 18b, which are close to equal and have e.g. absolute impedance values (at 50 Hz or 60 Hz) in the order of 1-10 ⁇ .
• the impedance devices 18a, 18b shall provide a larger capacitance than the stray capaci ⁇ tance of conductor 5 to ground, for example shall be larger by a factor 5 to 10.
• the impedance devices are typically capacitors having a capacitive and resistive part.
• Each switching assembly is arranged in parallel to one impedance device 18a, 18b, and all impedance devices are matched in order to evenly distribute the voltage applied to the switch over the switching assemblies la, lb.
• an impedance device 18c as shown, can be arranged between the two enclosures 2a, 2b.
• impedance devices 18a, 18b can be inserted between the metal enclosure 2a, 2b and those terminals of the switching assemblies la, lb that are connected to node 17.
• the impedance devices 18a, 18b are arranged within the metal enclosures 2a, 2b.
• the impedance devices 18a, 18b can be arranged outside the enclosures 2a, 2b, and can be arranged outside insulating cylinder 6 where there is more room to accommodate them.
• the impedance devices 18a, 18b each extend from an enclosure 2a, 2b to the node 17 between the switching assemblies la, lb.
• a node terminal 19 is arranged between the two switching assemblies la, lb, advantageously at equal distances from both switching assemblies.
• Node terminal 19 is electrically connected to conducting rod 5 and extends outside insulating cylinder 6.
• insulating cylinder 6 is split into two halves and node terminal 19 is arranged at the flanging point of the two halves.
• the two impedance devices 18a, 18b are each con ⁇ nected to node terminal 19 at one of their ends, and to the enclosures 2a, 2b at their other ends.
• the impedance devices 18a, 18b are, for example, capacitors, e.g. rated to some hundred kV each (e.g. 300 kV) . They act as grading capacitors and have a capacitance of at least 100 pF, in particular in the range of some 100 pF to some few nF.
• the metal enclosures 2a, 2b are electrically insulated from each other by a solid in ⁇ sulator, in particular by an electrically insulating cylinder and/or by an electrically insulating third section of a frame of the switch.
• the metal enclosures 2a, 2b are electrically insulated from each other by the electrically insulating cylinder 6 as disclosed in Fig. 1, 2, 6 and the accompanying description.
• the metal enclosures 2a, 2b are electrically insulated from each other by the electrically insulating third section lOg, lOj of the frame 10a, lOj of the switch as disclosed in Fig. 1, 2, 6 and the accompanying description.
• the metal enclosures 2a, 2b are electrically insulated from ground, in particular by a solid insulator 16a, 16b or a support insulator.
• metal enclosures 2a, 2b are electrically insulated from ground by the galvanically insulated power feeders 16a, 16b of the power supply of the actuators 15a, 15b, as disclosed in Fig. 1, 2, 6 and the accompanying description.
• the metal enclosures 2a, 2b are arranged in series to one another. In embodiments, each metal enclosure 2a, 2b is closed in a gas-tight manner.
• the first metal enclosure 2a enclosing the first switching assembly la and the second metal enclosure 2b enclosing the second switching assembly lb are each closed in a gas-tight manner.
• the switch is a high-voltage switch for ac or dc applications, in particular a high- voltage disconnector, a high-voltage circuit breaker, or a high-voltage current commutating device.
• the switch comprises two switching assemblies la, lb arranged in series. It can, however, comprise even more switching devices arranged in series, with each switching device mounted in its metal enclosure and with neighboring metal enclosures being electrically insulated from each other. With this design, the switch can be scaled to even higher voltages while reusing the same switching assembly and metal enclosure designs.
• each switching assembly 2a, 2b comprises one or more electrical switching units 4.
• Fig. 2 shows an embodiment with two such switching units 4. If several switching units 4 are provided, at least some of them are advantageously arranged in series for increasing the withstand voltage of the switching assembly.
• the metal enclosures 2a, 2b are not connected to ground.
• the metal enclosures 2a, 2b at the ends of the series arrangement of switching assemblies la, lb are connected (via a low-impedance connection) to the terminals 8a, 8b, respectively.
• the connection between the metal enclosures and the terminals may be of higher impedance.
• the impedances between the terminals and the adjacent metal enclosures as well as the impedances between neighboring metal enclosures are advantageously balanced such that (i) the voltage drops are the same, or at least approximately the same, over all switching assemblies, and (ii) the potential of each metal enclosure is in the center, or approximately in the center, between the potentials input and output terminals of the switching assembly that it encloses.
• An example of such a switch with three switching assemblies la, lb, lc and three metal enclosures 2a, 2b, 2c is shown in Fig. 4.
• Impedance devices Z are provided between each metal enclosure 2a, 2b, 2c and a node 17 between two neighbouring switching assemblies, and optionally between an end-side metal enclosure 2a and 2c and its neighbouring terminal 8a and 8c, respectively. At least the absolute impedances values of all impedance devices Z are chosen to be equal, or at least to be sufficiently similar, in which case the above conditions (i) and (ii) are met if the impedances to ground are neglected.
• the present switch is for example used for switching high voltages and low currents, e.g. at the location of device 10 in Fig. 2 of WO 2011/057675, the content of which in its entirety is herewith made part of the disclosure by reference.
• the high-voltage switch can comprise, for example, switching assemblies with high-voltage circuit breaking and/or high-voltage disconnecting function and/or high-voltage current commutating function.
• the high-voltage switch can be a high-voltage disconnector, a high-voltage circuit breaker, a high- voltage current commutating device, or similar devices.
• the switch can be used for dc as well as ac applications .
• it can e.g. be used for switching a dc voltage of 640 kV using two switching assemblies la, lb and metal enclosures 2a, 2b each being rated for approximately half that voltage. In this case, a typical distance between the two metal enclosures 2a,
• 2b can be in the order of some meters, such as 5 m - 6 m.
• 10a, 10b, ... , 10j frame j 10a, 10b, 10c: first section of frame j lOd, lOe, lOf: second section of frame

Landscapes

• Gas-Insulated Switchgears (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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ID=48537998

Family Applications (1)

Country Status (4)

Cited By (1)

Citations (9)

• 2013
  • 2013-05-31 EP EP13725993.3A patent/EP2856487B1/en active Active
  • 2013-05-31 WO PCT/EP2013/061262 patent/WO2013178787A1/en active Application Filing
  • 2013-05-31 CN CN201380028757.5A patent/CN104380422B/zh active Active
  • 2013-05-31 KR KR1020147033036A patent/KR102038724B1/ko active IP Right Grant

Patent Citations (9)

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