Patent Publication Number: US-2013250487-A1

Title: Switch bay for high-voltage switchgear assembly, and method for installation thereof

Description:
RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §120 to PCT/EP2010067593, which was filed as an International Application on Nov. 16, 2010 designating the U.S., the entire content of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     The present disclosure relates to a switch bay for a high-voltage switchgear assembly, such as a switchgear assembly having a busbar, for example. The present disclosure also relates to a switch bay having circuit breakers, switch disconnectors and busbar phase conductor sections. In addition, the present disclosure relates to a high-voltage switchgear assembly having such a switch bay, and to a method for installation of a high-voltage switchgear assembly. 
     BACKGROUND INFORMATION 
     Switchgear assemblies play an important role for power systems which transport electrical power from the power station to the end user. Switchgear assemblies such as these include one or more busbars and switch bays, which are used to couple incoming and outgoing lines of the power systems, for example cross-country lines, switchably to the busbars, or else to couple busbars switchably to one another. 
     Switchgear assemblies are subdivided into different voltages to be switched. In this case, high-voltage switchgear assemblies are considered to be switchgear assemblies having a rated voltage of at least 300 kV, for example, of at least 420 kV. Gas-insulated switchgear assemblies are frequently used for high and medium voltages, in which the conductors are surrounded by an inert gas such as SF 6 . For this purpose, the electrical components are arranged in a gas-tight housing (encapsulation), which defines a gas area for the inert gas. 
     On the basis of their encapsulation, high-voltage switchgear assemblies can be subdivided into two different types: on the one hand, one type with a three-phase-encapsulated busbar, that is to say, the phase conductors for all three current phases are accommodated in a common encapsulated gas area, and on the other hand, a type with single-phase-encapsulated busbar, that is to say, the individual phase conductors of the busbar, one for each of the generally three current phases which occur have individual encapsulation, at least in places, and are therefore separated from one another by housing sections. 
     The choice of the respective type of switchgear assembly (three-phase or single-phase encapsulated) is largely predetermined by the rated voltage to be switched. For example, switchgear assemblies with a single-phase-encapsulated busbar are predominantly used for a rated voltage of at least 300 kV and in particular of at least 420 kV. The single-phase encapsulation allows very effective shielding of the high voltages which occur. However, the design of single-phase-encapsulated switchgear assemblies is complex and space-consuming, since a dedicated housing must be provided for each phase conductor of the busbar. These housings also have to have a certain volume in order to allow sufficient separation of the conductors from the grounded housing parts, thus adequately reducing the risk of an electrical breakdown. 
     Since the energy demand is growing, particularly in economically emerging regions, it is desirable to be able to set up a switchgear assembly in as short a time as possible, in order to satisfy this demand quickly. However, particularly in the case of a high-voltage switchgear assembly with a single-phase-encapsulated busbar, this is difficult because a switchgear assembly such as this must be assembled, as described, from a large number of individual parts and must then be subjected to comprehensive functionality tests, and the construction is therefore complex and time-consuming. In addition, high-voltage switchgear assemblies such as these with a single-encapsulated busbar also have a relatively space-consuming construction, and it is desirable to reduce this space requirement as much as possible in areas where the available space is restricted, for example in the vicinity of highly populated regions. Finally, the most important requirement for a switchgear assembly is operational safety, and no compromises should be made relating to this. 
     SUMMARY 
     An exemplary embodiment of the present disclosure provides a switch bay for a high-voltage switchgear assembly. The high-voltage switchgear assembly includes a busbar having three busbar phase conductors each respectively provided for a corresponding one of a first current phase, a second current phase and a third current phase. The exemplary switch bay includes three gas-insulated circuit breakers each respectively provided for a corresponding one of the first current phase, the second current phase and the third current phase. The circuit breakers being arranged parallel to one another along an x direction. The exemplary switch bay also includes three switch disconnectors each respectively provided for a corresponding one of the first current phase, the second current phase and the third current phase. The switch disconnectors each have a corresponding isolating gap, respectively, where the three isolating gaps are arranged parallel to one another. In addition, the exemplary switch bay includes a first busbar phase conductor section of the first current phase and a second busbar phase conductor section of the second current phase. The first and the second busbar phase conductor sections extend parallel to one another along a y direction, which runs transversely with respect to the x direction. Furthermore, the exemplary switch bay includes a busbar connection for connection of a third busbar phase conductor section of the third current phase. The first and the second busbar phase conductor sections and the busbar connection are configured to be electrically connected via the corresponding switch disconnector of the respective current phase to the circuit breaker of the respective current phase. The second busbar phase conductor section defines a boundary plane which runs in the x and y directions and contains a center of the second busbar phase conductor section. Each of the three isolating gaps is arranged at least partially on a side of the boundary plane which faces the three circuit breakers. The first busbar phase conductor section, the second busbar phase conductor section and the third busbar phase conductor section are arranged one above the other in a z direction, which runs transversely with respect to the x and y directions, after connection of the third busbar phase conductor section of the third current phase to the busbar connection of the switch bay. 
     An exemplary embodiment of the present disclosure provides a high-voltage switchgear assembly having the above-described switch bay. 
     An exemplary embodiment of the present disclosure provides a method for installation of a high-voltage switchgear assembly. The exemplary method includes providing a preassembled switch bay, such as the above-described switch bay, in a standardized transport container physically remotely from an installation location for the high-voltage switchgear assembly. The switch bay has the aforementioned first busbar phase conductor section of the first current phase, and the aforementioned second busbar phase conductor section of the second current phase. The exemplary method also includes transporting the switch bay in the transport container to the installation location for the high-voltage switchgear assembly, and connecting the third busbar phase conductor section of the third current phase to a busbar connection of the switch bay, such that the busbar phase conductor section of the third current phase has a physical height which is greater than an internal height of the transport container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional refinements, advantages and features of the present disclosure are described in more detail below with reference to exemplary embodiments illustrated in the drawings, in which. Different individual features can also be omitted or can be combined with other features. In the drawings: 
         FIG. 1  shows a perspective view of a switch bay according to an exemplary embodiment of the present disclosure; 
         FIGS. 2   a  to  2   c  show side cross-sectional views of the switch bay shown in  FIG. 1 ; and 
         FIG. 3  shows a front view of the switch bay shown in  FIGS. 1 to 2   c.    
     
    
    
     DETAILED DESCRIPTION 
     According to an exemplary embodiment of the present disclosure, a switch bay is provided for a high-voltage switchgear assembly. The switch bay includes a busbar having in each case one busbar phase conductor for a first current phase, a second current phase and a third current phase. The switch bay in each case includes a corresponding gas-insulated circuit breaker for the first, second and third current phases, respectively, wherein the circuit breakers are arranged parallel to one another along an x direction. Furthermore, the switch bay in each case includes a corresponding switch disconnector for the first, second and third current phases, respectively, wherein the switch disconnectors each have an isolating gap, and wherein the isolating gaps are arranged parallel to one another. Furthermore, the switch bay includes a first busbar phase conductor section of the first current phase and a second busbar phase conductor section of the second current phase, wherein the first and the second busbar phase conductor sections extend parallel to one another along a y direction, which runs transversely with respect to the x direction. Furthermore, the switch bay includes a busbar connection for connection of a third busbar phase conductor section of the third current phase. The first and the second busbar phase conductor sections and the busbar connection can be electrically connected via the switch disconnector of the respective current phase to the circuit breaker of the respective current phase. The second busbar phase conductor section defines a boundary plane as that plane which runs in the x and y directions and contains a center of the second busbar phase conductor section. Each of the three isolating gaps is arranged at least partially on that side of the boundary plane which faces the three circuit breakers. 
     According to an exemplary embodiment of the present disclosure, a method is provided for installation of a high-voltage switchgear assembly. In this case, the activity of installation also includes, for example, the production, equipment and/or repair of a switchgear assembly such as a switchgear assembly including the above-described switch bay. The method includes the provision of a preassembled switch bay, for example, any switch bay described herein, in a standardized transport container physically remotely from an installation location for the high-voltage switchgear assembly, wherein the switch bay has a first busbar phase conductor section of the first current phase and a second busbar phase conductor section of the second current phase. In the transport state, the switch bay, and for example, busbar phase conductor sections for the first and the second of the current phases and a busbar connection for the third current phase of the switch bay, therefore has a physical height which is less than the internal height of the transport container. The method also includes the transportation of the switch bay in the transport container to the installation location for the high-voltage switchgear assembly. In a number of exemplary embodiments, the switch bay is at least partially filled with inert gas during transportation. Furthermore, the method includes the connection of a third busbar phase conductor section of the third current phase to a busbar connection of the switch bay, such that the busbar phase conductor section of the third current phase has a physical height which is greater than an internal height of the transport container. 
     In this case, numerical details such as two busbar phase conductor sections should in principle be understood as meaning that at least two busbar phase conductor sections are provided. It is therefore also possible to provide more than two busbar phase conductor sections, for example. 
     A switch bay  1  according to an exemplary embodiment of the present disclosure will be described with reference to  FIG. 1 . In general, a switch bay is defined herein such that it includes at least in each case one circuit breaker, one switch disconnector and one busbar phase conductor section and/or one busbar connection for connection to a busbar phase conductor for each of, for example, three current phases. In other words, for a configuration including first, second and third current phases, for example, the switch bay includes three circuit breakers, three switch disconnectors, and three busbar phase connectors and/or busbar connections for connection to a busbar phase conductor for each of a corresponding one of the three current phases, respectively. The switch bay need not yet be connected to the busbar. 
     The switch bay  1  illustrated in  FIG. 1  is intended to be coupled to a double busbar, with the double busbar having a first busbar and a second busbar, each having three phase conductors. These phase conductors are designed to support a respective current phase of three-phase current. The switch bay  1  includes sections of these phase conductors. For instance, respective busbar modules  170 ,  270  and  370 , with corresponding busbar phase conductor sections  174 ,  274  and  374 , are illustrated for the first busbar. Corresponding busbar modules  190 ,  290  and  390  with corresponding busbar phase conductor sections  194 ,  294  (see  FIGS. 2   b ) and  394  are likewise illustrated for the second busbar. These busbar phase conductor sections are single-phase-encapsulated in the respective busbar modules. The busbar modules  170 ,  270 ,  370  as well as  190 ,  290  and  390  have connections  172 ,  272 ,  372 ,  192  (see  FIGS. 2   a ),  292  and  392  for connection of further sections of the respective busbar phase conductor. By way of example, further sections of the busbar phase conductor are illustrated, which are connected to a number of these connections: by way of example, a module  390 ′ with a further phase conductor is connected to the connection  392  of the busbar module  390 . The module  390 ′ in turn has a further connection  392 ′ for further modules such as these. 
     The switch bay  1  includes a corresponding switch bay component  100 ,  200  or  300  for each of the three current phases, and these switch bay components can be coupled to the busbar phase conductors of the corresponding current phase. The switch bay components  100 ,  200  and  300  are largely similar to one another, apart from the differences described further below. The switch bay component  300  for the third current phase will be described first of all. 
     The switch bay component  300  has a circuit breaker module  310  in which a circuit breaker is arranged. The circuit breaker module  310  furthermore has a first outlet  315  and a second outlet, to which a connection piece  340  is connected. The two outlets face in the same direction, that is, in a z direction. The circuit breaker module  310  furthermore has a stand frame  318 . 
     The connection piece  340  is T-shaped and has a bottom outlet (facing in the z direction) and two mutually opposite side outlets (facing in an x direction). As described above, the connection piece  340  is connected to the corresponding outlet of the circuit breaker module  310  by means of the bottom outlet. One of the side outlets of the connection piece  340  is connected via a switch disconnector module  350  to the busbar module  370 , and the other of the side outlets is connected via a switch disconnector module  380  to the busbar module  390 . The circuit breaker module  310 , the connection piece  340 , the switch disconnector module  350  or  380  and the respective busbar module  370  or  390  have respective conductor sections, which run in their interior, and respective housing sections, with the respective housing sections defining respective gas volumes for a dielectric inert gas which surrounds the respective conductor sections. These gas volumes can be intrinsically closed or can be connected to gas volumes of adjacent modules for the inert gas, for example, via post-type insulators through which gas can pass. 
     The two further switch bay components  100  and  200  for the other current phases are designed in a similar manner, and the above description also applies in a corresponding manner to them. Further details relating to the three switch bay components  100 ,  200 ,  300  are described further below, for example, with reference to  FIGS. 2   a  to  2   c.    
     The three circuit breaker modules  110 ,  210 ,  310  and the circuit breakers provided in them are arranged parallel to one another and define an x direction as one axis of the circuit breakers (for example, the axis  112   a  in  FIG. 2   a ). The circuit breakers  110 ,  210 ,  310  are separated from one another in a y direction, and are therefore arranged on a circuit breaker plane (x-y plane). 
     The busbar phase conductor sections  174 ,  274 ,  374  of the first busbar are also arranged parallel to one another and define a y direction as the direction parallel to which they are arranged. The indication of a direction herein does not include any absolute position indication, and is not influenced by parallel movement. In addition, the phase conductor sections  194 ,  294 ,  394  of the second busbar are arranged parallel to one another, and parallel to the y direction. 
     In the switch bay  1  shown in  FIG. 1 , the x, y and z directions are mutually perpendicular and therefore form a Cartesian coordinate system. However, this is not essential. In accordance with other exemplary embodiments, these directions can also be transverse with respect to one another, that is to say not parallel. In other exemplary embodiments, at least two, for example, all three, of the x, y and z directions include an angle of at least 60° with one another, and/or are mutually perpendicular. 
     As can be seen in more detail in  FIGS. 2   a  to  2   c,  the busbar phase conductor sections  194 ,  294 ,  394  are arranged one above the other in the z direction. Therefore, the busbar phase conductor sections, for example, their center axes, are arranged on a busbar plane (plane  8   a  in  FIG. 2   b , that is to say a y-z plane). However, other arrangements of the phase conductor sections  194 ,  294 ,  394  are also possible. The connection pieces  140 ,  240  and  340  are identical to one another. 
       FIG. 2   a  shows a side cross-sectional view of the switch bay  1  on a cross-sectional plane which is at right angles to the y direction, that is to say the direction of the first phase conductor section  174 , and which runs through a center of the first circuit breaker module  110 . The first switch bay component  100  will be described in more detail with reference to  FIG. 2   a.    
     Analogously to the third switch bay component  300  described above, the first switch bay component  100  also has a circuit breaker module  110  with a stand frame  118 . The stand frame  118  defines a base plane  6 , and the switch bay  1  is arranged completely above the base plane  6 . The circuit breaker module  110  has a circuit breaker  112  (illustrated schematically) and a circuit breaker housing  111 , which allows gas-tight encapsulation of the circuit breaker  112 . The circuit breaker  112  has an isolating gap. As used herein, an isolating gap is defined as a gap which forms an isolation gap between two ends of a switch when the switch is open, but which can be bridged by a moving switching element by closing the switch, in order to make an electrical connection between the two ends of the switch. The circuit breaker  112  can be operated by a drive module  113 , which can move the moving switching element in order to open or to close the switch. The circuit breaker  112  defines a circuit breaker axis  112   a,  for example, as a movement axis of the moving switching element of the circuit breaker. This circuit breaker axis  112   a  defines the x direction. 
     The circuit breaker module  110  furthermore has a conductor piece  114  on one side of the isolating gap, and a further conductor piece  116  on another side of the isolating gap. The conductor piece  114  leads to a connection  115 , to which further modules of the switch bay  1  can be connected, in order to be electrically connected to the conductor piece  114 . Such further modules can, for example, be a switch disconnector module, a grounding switch module, a current transformer module, a voltmeter module, a cross-bay coupling module for coupling to the second busbar, a connecting module for coupling to external lines (under ground or above ground), and/or a combination of such modules. The connection  115  of the circuit breaker is directed in the z direction. The connection  115  has a connecting flange, which lies in the x-y direction. The further conductor piece  116 , which is arranged on the other side of the circuit breaker  112 , leads to a connection  117 , which likewise faces in the z direction and has a connecting flange which runs in the x-y direction. The conductor piece  116  passes through an insulator, for example, a post-type or bulkhead insulator  117   a.  The insulator  117   a  is arranged on the same plane as the connection  117  (x-y plane). 
     A connection piece  140  is connected to the connection  117  of the circuit breaker module  110 . The connection piece  140  is T-shaped and, in addition to the bottom outlet which is connected to the connection  117  of the circuit breaker module  110 , has two mutually opposite side outlets  148 . An electrical conductor with a conductor section  145  which is electrically connected to the conductor section  116  of the circuit breaker module  110  runs in the interior of the connection piece  140 . The conductor piece  145  leads to a node point from which further conductor pieces  146  lead at the side to the side outlets  148  of the connection piece  140 . The conductor sections  145  and  146  therefore extend like a star from the node point to the respective side outlets  148  and to the bottom outlet. The connection piece  140  can also have an optional voltmeter. 
     The side outlets  148  are provided with a flange which runs on the z-y plane and with a disk-type insulator which is arranged on the same plane as the flange. Furthermore, the connection piece  140  has a housing which can close the interior thereof in a gas-tight manner, in order to hold the insulating gas therein. Furthermore, the T-like connection piece  140  has an optional current transformer  142 . The current transformer  142  is designed to measure a current flowing through the conductor piece  145 . In accordance with an exemplary embodiment, the current transformer  142  can include magnetic coils, which can measure the current contactlessly by magnetic induction. The current transformer  142  can be arranged outside the gas volume defined by the housing. 
     A switch disconnector module  150  is fitted to one of the side outlets  148  of the connection piece  140 . One inlet  158  of the switch disconnector module  150  is fitted to the side outlet  148  of the connection piece  140 , for example, via a flange connection between the flange on the side outlet  148  and a flange which matches this on the inlet  158 . The switch disconnector module  150  has a switch disconnector  152  with an isolating gap  154 . One side of the isolating gaps  154  is electrically connected to the circuit breaker  112  via conductor sections, for example,  146  and  145 . The other side of the isolating gap  154  is connected via a busbar connection conductor section  156  to the busbar phase conductor section  174 , which will be described in more detail below. The busbar phase conductor section  174  can therefore be electrically connected to the circuit breaker  112  via the switch disconnector  152 . 
     The switch disconnector  152  has a stationary contact piece and a moving contact piece, which can be disconnected from one another by the isolating gap  154 . In alternative exemplary embodiments, the switch disconnector can also have two moving contact pieces, one for each of the two sides of the isolating gap  154 . The moving contact piece can be moved in order to selectively bridge or to disconnect the isolating gap  154 . The isolating gap runs in the z direction. In a number of exemplary embodiments of the present disclosure, the z direction can even be defined by the direction of the isolating gap. In the illustrated exemplary embodiment, the moving contact piece can also be moved along the z direction, or else the movement direction of the moving contact element can define the z direction. 
     The moving contact element of the switch disconnector  152  is arranged on that side of the isolating gap  154  which is electrically connected to the circuit breaker  112 . The moving contact element of the switch disconnector  152  is physically arranged on that side of the isolating gap  154  which faces away from the circuit breaker. 
     The switch disconnector module  150  merges smoothly into a first busbar module  170 . In other words, the switch disconnector module  150  and the first busbar module  170  are formed integrally with one another and have a common housing. The common housing defines an internal area which can be closed in a gas-tight manner and in which the switch disconnector  152  and the first busbar phase conductor section  174  are arranged. The first busbar phase conductor section  174  extends in the y direction or defines the y direction, and a housing section  171  of the first busbar module  170  extends at least in places cylindrically around the first busbar phase conductor section  174 . 
     The circuit breaker module  110 , the connection piece  140  and the switch disconnector module  150  with the first busbar module  170  therefore define a gas area, or a plurality of gas areas, which allow a connection, encapsulated by inert gas, from the circuit breaker  112  to the first busbar phase conductor section  174 . 
     A further switch disconnector and busbar module  190  is arranged at the further side outlet of the connection piece  140  and contains a switch disconnector  182  and a further busbar phase conductor section  194 . The switch disconnector and busbar module  190  is designed in a corresponding manner to the switch disconnector module  150  and busbar module  170  already described above. 
     Furthermore,  FIG. 2   a  shows a second busbar module  270  and a third busbar module  370  with corresponding busbar phase conductor sections  274  and  374 , respectively, for the second and third current phase, respectively, of the first busbar. Optional busbar modules  290  and  390  with corresponding busbar phase conductor sections are likewise illustrated for the second and third current phase, respectively, of the second busbar. These modules will be described in more detail further below with reference to  FIGS. 2   b  and  2   c.    
     A boundary plane  2  is defined as the plane which runs in the x direction (that is to say parallel to the circuit breaker axis  112   a ) and in the y direction (that is to say parallel to the first or second busbar phase conductor section  174 ,  274 ) and contains a center of the second busbar phase conductor section  274 . The isolating gap  154  is arranged completely on the side of the circuit breaker  112  with respect to the boundary plane  2 . In other exemplary embodiments of the present disclosure, the isolating gap  154  can also extend into the boundary plane  2 , as a result of which it is arranged only partially on that side of the boundary plane  2  which faces the circuit breaker  112 . However, the majority of the isolating gap  154  can be arranged on that side of the boundary plane  2  which faces the circuit breaker  112 , for example, with at least up to 70% or even up to at least 90% of its length being arranged on that side of the boundary plane  2  which faces the circuit breaker  112 . Advantages of this arrangement will be explained further below. 
     A second component  200  of the switch bay, which is intended for the second current phase, will be described with reference to  FIG. 2   b.  This second component  200  is designed in a corresponding manner to the first component  100 , which has been explained with reference to  FIG. 2   a,  and the reference symbols for the component  200  that start with 2 correspond to the reference symbols of the component  100  which start with 1. With this revision to the reference symbols in mind, the description of  FIG. 2   a  also applies to  FIG. 2   b,  apart from the differences which can be seen in the Figure and which will be described below. 
     As can be seen in  FIG. 1 , the circuit breaker  212  is arranged parallel to the circuit breaker  112  for the first current phase, that is to say, the axis  212   a  likewise extends in the x direction. The circuit breaker  212  is offset in the y direction with respect to the circuit breaker  112  (see  FIG. 1 ). Further modules of the component  200  are also correspondingly offset in the y direction with respect to the corresponding modules of the component  100 . The connection piece  240 , the switch disconnector module  250  and the second busbar module  270  provide a gas-insulated path for a conductor which runs from the circuit breaker  212  to the second busbar phase conductor section  274  for the second current phase, and can be disconnected only by the switch disconnector  252 , for example, its isolating gap  254 . The outlet  248  is arranged at the same height as the outlet  148  in  FIG. 2   a  (that is to say at the same distance in the z direction from the base plane  6 ) and, correspondingly, the node point between the conductor sections  245  and  246  of the connection piece  240  is also arranged at the same height as the corresponding node point of the connection piece  140  shown in  FIG. 2   a.  The second busbar phase conductor section  274  extends parallel to the first busbar phase conductor section  174 , that is to say along the y direction. 
     The second busbar phase conductor section  274  is arranged offset in the z direction with respect to the first busbar phase conductor section  174 . The busbar modules  170  and  270  (and  370 ) are therefore arranged along a busbar plane  8   a  which runs in the y and z directions. To be more precise, the two (three) busbar phase conductor sections  174 ,  274  (and  374 ) run on the busbar plane  8   .    
     The height of the center of the outlet  248  of the connection piece  240  (in the z direction above the base plane  6 ) is located precisely centrally between the height of the first busbar module  170  and that of the second busbar module  270 . This allows the switch disconnector and busbar module  250 ,  270  to be designed in precisely the same manner as the corresponding module  150 ,  170  from  FIG. 2   a,  with the difference that the module  250 ,  270  from  FIG. 2   b  is rotated through 180° about the x axis. The use of a module of the same design for the first current phase (module  150 ,  170  in  FIG. 2   a ) and for the second current phase (module  250 ,  270  in  FIG. 2   b ) reduces the number of different parts, and therefore allows efficient production and maintenance with fewer different parts. This also applies to the use of the same connection pieces  140 ,  240 ,  340 . 
     Because of the rotation through 180°, the moving contact element in the switch disconnector  252  is spatially arranged on the other side of the isolating gap  254  than in the case of the switch disconnector  152 . In the switch disconnector  252 , the moving contact element is arranged on that side of the isolating gap  254  which faces the circuit breaker  212 . More generally, the switch disconnector  154  and the switch disconnector  254  are aligned in opposite senses to one another, for example, with their moving contact pieces being arranged on different sides of the respective isolating gaps, that is to say with the moving contact piece of one of the switch disconnectors  154 ,  254  being arranged on the side facing the circuit breakers, and with the moving contact piece of the other of the switch disconnectors  154 ,  254  being arranged on the side facing away from the circuit breakers. 
     What has been said for the switch disconnector and busbar module  250 ,  270  correspondingly also applies to the module  290 , which is fitted to the second side outlet of the connection piece  240 , with the switch disconnector  282  and the busbar phase conductor section  294  for the second current phase of the second busbar. For the second busbar as well, the busbar modules  190 ,  290 ,  390 , to be precise the busbar phase conductor sections  194 ,  294 ,  394  which are arranged in them, are arranged along a busbar plane  8   b,  which runs in the z-y direction. 
     The circuit breaker modules (in  FIG. 2   b:  module  210 ; likewise also modules  110 ,  310 ) each have two power outlets  215  and  217 . The centers of the outlets  215  are offset by a common distance twice m with respect to the centers of the outlets  217  in the x direction, that is to say by twice the length m indicated in  FIG. 2   b.  In a number of exemplary embodiments of the present disclosure, this distance twice m is three times the module size of one component. For example, the module size can be 720 mm, and the distance twice m can be 2160 mm. 
     In a number of exemplary embodiments of the present disclosure, the busbar plane  8   a  is offset through a common distance m in the x direction with respect to the outlets  217 , away from the outlets  215 . The busbar plane  8   a  is therefore at a distance m from the first outlets  215  and at a distance  3   m  from the second outlets  217 . These exemplary embodiments correspond, for example, to a variation of the switch bay shown in  FIGS. 2   a - 2   c,  in which the proportions are chosen such that the three lengths illustrated as m in  FIG. 2   b  are the same. 
     In a number of exemplary embodiments of the present disclosure, the busbar plane  8   b  is arranged centrally between the outlets  215  and  217  of the circuit breakers, in each case at a distance m. This also allows a connection to be made between the outlet  215  and the second busbar (plane  8   b ), for example, for a coupling module, using the same components as those fitted to the outlet  217 . This central arrangement is particularly advantageous in exemplary embodiments having a double busbar. 
     A third component  300 , which is intended for the third current phase of the switch bay will be described with reference to  FIG. 2   c.  This third component  300  is designed in a corresponding manner to the first and second components  100 ,  200 , which have been explained with reference to  FIGS. 2   a ,  2   b,  and the reference symbols for the component  300  which start with 3 correspond to the reference symbols of the components  100  and/or  200  which start with 1 and 2. With this revision to the reference symbols in mind, the description relating to  FIGS. 2   a  and  2   b  also applies to  FIG. 2   c,  apart from the differences which can be seen in  FIG. 2   c  and which will be described further below. 
     The circuit breaker module  310  is therefore designed in a corresponding manner to the circuit breaker modules  110 ,  210 , and the circuit breaker axis  312   a  runs parallel to the circuit breaker axes  112   a  and  212   a,  that is to say parallel to the x direction. These axes  112   a,    212   a,    312   a  are offset with respect to one another by the same amount in the y direction (see  FIG. 1 ). The connection piece  340  is also designed in a corresponding manner to the connection pieces  140  and  240 , and its outlets  348  are at the same distance from the base plane  6  in the z direction as the outlets  248  and  148  of the corresponding connection pieces for the first and second current phases, respectively. In addition, the node point between the conductor sections  346  and  345  is at the same distance from the base plane  6  in the z direction as the corresponding node points in  FIG. 2   a  and  FIG. 2   b,  as a result of which these node points, for example, the outlets of all three connection pieces  140 ,  240 ,  340 , lie along a straight line which runs in the y direction. 
     A switch disconnector module  350  is connected to the outlet  348 . The switch disconnector module contains a switch disconnector  352  with an isolating gap  354 . This switch disconnector is designed in a similar manner to the switch disconnector  252  in  FIG. 2   b,  and, in particular, the moving contact piece of the switch disconnector  352  is arranged physically on the same side of the isolating gap as that in the switch disconnector  252 , for example, on that side of the isolating gap  354  which faces the circuit breaker  312 . Like the other isolating gaps  154  and  254 , the isolating gap  354  is also arranged on the side of the circuit breaker  312  opposite the boundary plane  2 . 
     The isolating gaps  154 ,  254 ,  354  are arranged parallel to one another. This expression parallel also includes an anti-parallel arrangement, that is to say with elements rotated through 180°. The isolating gap  354  is therefore arranged in the z direction. 
     In contrast to the situation with the components  100  and  200 , in the component  300 , the switch disconnector module  350  is not designed jointly with a busbar module. Instead of this, the switch disconnector module  350  has a busbar connection  359 . The busbar connection  359  faces in the z direction. Furthermore, the busbar connection  359  is equipped with a flange which lies on the x-y plane. A conductor section  356  leads to the busbar connection  359 . The conductor section  356 , and therefore the busbar connection  359 , can be electrically connected to the circuit breaker  312  via the switch disconnector  352 . 
     The busbar module  370  is removably connected to the busbar connection  359 , for example, via a flange connection between the flange of the busbar connection  359  and a flange, which matches this, on a corresponding connection  378  of the busbar module  370 . A bulkhead insulator  359   a  is arranged between these flanges. The bulkhead insulator  259   a  is arranged on a side of the boundary plane  2  which faces away from the circuit breakers, and extends parallel to the boundary plane  2 . Instead of a bulkhead insulator, it is also possible to use a post-type insulator. 
     The busbar module  370  is removable. In other words, the busbar connection  359  is designed for connection of a third busbar phase conductor section  374  such that a third busbar module  370  of the third current phase can be formed, in which third busbar module  370  the third busbar phase conductor section  374  is arranged. 
     The busbar module  370  contains the third busbar phase conductor section  374  for the third current phase, and a housing section  372  which cylindrically surrounds the busbar phase conductor section  374 . Furthermore, the busbar module  370  contains a conductor section  376  which connects the busbar phase conductor section  374  to the outlet  378 , and makes an electrical connection to the conductor section  356  via the outlet  378 . The conductor sections  276 ,  256  therefore represent an electrical connection from the busbar phase conductor section  372  to the switch disconnector  352  and, via this switch disconnector, make a selectively disconnectable electrical connection to the circuit breaker  312 . 
     The fact that the busbar module  370  is removable (by releasing the connection between the busbar connection  359  and the corresponding connection  378  of the busbar module  370 ) has major advantages for transportation of the switch bay. For example, this arrangement makes it possible to achieve a reduced physical height. The physical height is in this case defined as the height in the z direction or in the direction at right angles to a circuit breaker plane on which the circuit breakers are arranged. According to an exemplary embodiment, the physical height is the height of the switch bay measured from the lowest part of the switch bay, for example, from a stand frame of the circuit breaker arrangements or from the base plane  6  which is defined by this frame. Downward is in this case defined as the direction in the z direction from the boundary plane  2  to the circuit breakers. 
     When the third busbar module  370  is fitted, the physical height of the switch bay is predetermined by this module  370 . When the section  374  is removed, the physical height in contrast corresponds to the distance in the z direction between a transport height plane  4  and the base plane  6 . This reduced physical height is predetermined by the second busbar module  270  and/or by the busbar connection  359  for the third current phase. This is because, when the busbar module  370  is removed (and correspondingly the further busbar module  390 ), the switch bay is located completely between the base plane  6  and a transport height plane  4 . All the remaining parts of the switch bay, such as the busbar modules  270 ,  170  and the switch disconnector module  350 , are arranged between these two planes  6  and  4 . When the busbar module  370  (and  390 ) is removed, the switch bay is in a transport state, and can be located in a standard transport container, whose internal height is not greater than the distance between the planes  6  and  4 . 
     In addition, when the busbar module  370  (and  390 ) has been removed or has not been fitted, the switch disconnector modules  350  (and  380 ) together with the corresponding switch disconnectors  352  (and  382 ) for the third current phase are still fitted to the switch bay. This means that these moving parts have also already been fitted when in a transport state, in which the switch bay is located in the transport container. These moving parts therefore no longer need to be fitted at the installation location, but the assembly and pretesting can be carried out even before transportation, which provides considerable time saving for fitting and testing at the installation location. 
     According to an exemplary embodiment of the present disclosure, each of the three isolating gaps  154 ,  254 ,  354  is arranged at least partially below the boundary plane  2  (e.g., arranged on the side facing the three circuit breakers  112 ,  212 ,  312 ). As a result, this arrangement makes it possible to achieve a small physical height, as will be explained below. The busbar modules  170  and  270  also extend into an area which is located somewhat above the busbar phase conductor sections  174  and  274 . By way of example, a part of the gas volume for the inert gas is also located in this area. Therefore, when the third busbar phase conductor has been removed, the switch bay also extends somewhat above the boundary plane  2  which is defined by the busbar phase conductor sections  174  and  274 . The additional height corresponds at least to the distance which is required to dielectrically isolate the voltages which occur. One measure for this distance is the radius of the cylindrical housing section of the second busbar module  270 . 
     In general, the switches  152 ,  252 ,  352  also still require a certain amount of additional space above the isolating gaps  154 ,  254 ,  354 . This additional space is required for the respective switch contacts and for their dielectric isolation. In addition, the additional minimum height above the isolating gaps  154 ,  254 ,  354  which is required for this purpose corresponds, in terms of the order of magnitude, to the distance which is required for effective encapsulation of the voltages which occur. 
     Since the three isolating gaps  154 ,  254 ,  354  are arranged at least partially below the boundary plane  2 , it is therefore possible to achieve a physical height which is not significantly further above the second busbar or the boundary plane  2  than is necessary in any case for dielectric isolation of the busbar phase conductor sections  174  and  274 . This therefore allows a transport configuration which contains major moving parts of the switchgear assembly, in particular the switch disconnectors, but its physical height, or transport height plane  4 , is nevertheless low. 
     In a number of exemplary embodiments of the present disclosure, the transport height plane  4  is separated from the boundary plane  2  by less than the distance d (distance in the z direction between the first and the second busbar phase conductor sections  174  and  274 , see  FIG. 2   b ). In other exemplary embodiments, the transport height plane  4  is separated from the boundary plane  2  by less than 80 cm. 
       FIG. 3  illustrates a switch bay in the transport state. To be more precise,  FIG. 3  shows a transport unit  10 , one transport container  13  and the switch bay as illustrated in  FIGS. 1 to 2   c  in the transport state, that is to say without the third busbar modules  370 ,  390 . The reference symbols in  FIG. 3  correspond to the reference symbols in  FIGS. 1 to 2   c,  and reference is therefore made to the corresponding description relating to  FIGS. 1 to 2   c  for their explanation. In addition a gas-tight attachment  359   b  is fitted to the connection  359  of the switch disconnector module  350  and, for example, makes it possible for an inert gas to be stored at a raised pressure in the switch disconnector module  350 , without the insulator  359   a,  which is arranged under the attachment  359   b  (see  FIG. 2   c ), bursting. The attachment  359   b  likewise protects the insulator  359   a  against contamination, and in this way prevents the possibility of contamination entering the interior of the switch bay. 
     The switch bay in  FIG. 3  also has the drive module  113 ,  213 ,  313 , which is equipped for operation of the switch disconnectors  152 ,  252 ,  352  and of the circuit breakers  112 ,  212 ,  312 . In the transport state as well, the drive module  113 ,  213 ,  313  is connected to the switch disconnectors and to the circuit breakers such that they are ready to operate, that is to say all the connections which are required for operation, for example electrical and/or mechanical connections, between the drive module and the switch disconnector or circuit breaker are connected. Instead of common drive modules  113 ,  213 ,  313 , it is also possible to provide separate drive modules for different switches (the circuit breaker and the switch disconnectors). Optionally, a control unit is also fitted, and is connected such that it is ready to operate, in order to control the circuit breakers and the switch disconnectors as well as other components of the switch bay. 
     The dimensions of the switch bay are such that the switch bay can be located in a standardized transport container  13 . The physical height of the busbar connection  359 , that is to say of the switch bay with the third busbar module  370  (and  390 ) removed, is, for example, less than 270 cm. The height of 270 cm corresponds approximately to the internal height of an exmeplary standard transport container (of the “high cube” type with an overall external height of approximately 290 cm). The physical height of the switch bay with the third busbar module  370  fitted is, in contrast, more than 270 cm. 
     The switch bay in  FIG. 3  has been preassembled ready for transport. This means that the switch bay can be transported simply by insertion, if required, into a standard container, and the container can be transported away. In addition, this means that the parts of the switch bay which are already present are fitted to one another as is envisaged for operation of the switch bay, corresponding to the switch bay, constructed completely ready for operation, of the high-voltage switchgear assembly (with the exception of the busbar modules  370 ,  390 ). 
     The busbar connection  359  has no busbar phase conductor section, that is to say that it has no busbar phase conductor section, no busbar phase conductor section is connected to it, the busbar phase conductor section  370  (and  390 ) has been removed, and the connection  359  (and  389 ) has in this sense been removed. 
     The transport container  13  can be a standard transport container. Standard transport containers are standardized throughout the world in accordance with ISO  668 , and are also referred to as freight or sea-freight containers. Transport containers are standardized for maritime use, and they can therefore easily be stacked. In particular, the following standards have been implemented in this context: on the one hand the so-called TEU container (20 foot equivalence container) with a length of approximately 6.1 m, a width of approximately 2.4 m. Further standard containers are the FEU (“forty foot equivalent unit”) container with a length of approximately 12.2 m; the forty-five foot equivalent unit container with a length of approximately 13.7 m; as well as 48-foot and even 53-foot (length: 16.15 m) containers. These containers (which are also referred to as transport containers or transportable standard containers) also all have the same width as the TEU container, that is to say approximately 2.4 m. In a so-called normal-cube embodiment, the transportable standard containers have a height of approximately 2.6 m; and in a high-cube embodiment, they have a height of approximately 2.9 m. These are external dimensions. The internal dimensions can be somewhat smaller. For instance, the internal height of the container is generally somewhat less than the overall height mentioned above, because of the wall thickness of the container, but the overall height can also be assumed to be the theoretical maximum value for the internal height. An exemplary internal height is 20 cm less than the overall height, that is to say 270 cm in the case of the high cube container. Shipment using standard containers such as these is considerably more cost-effective than shipment in tailormade containers, which cannot be transported without problems on standard container ships. It is therefore advantageous for the physical height of the switch bay when in the transport state, that is to say the distance between the base plane  6  and the transport height plane  4  which is parallel to the base plane  6 , to be less than 290 cm or 270 cm (the maximum or exemplary internal height of a standard transport container), or even less than 260 or 240 cm (the maximum or exemplary internal height of a TEU container). It is furthermore advantageous for the width (on the x-y plane or in a direction at right angles to the circuit breaker axis) to be less than 2.4 m. 
     The transport height plane  4  is governed mainly by the height of the second busbar, that is to say by the boundary plane  2 . This is because the transport height plane  4  is higher than this boundary plane  2  by at least the radius of the housing section for the second busbar, as can easily be seen in  FIG. 3  and in  FIG. 2   b.  However, this radius cannot be chosen to be indefinitely small since a certain minimum radius is required for effective shielding of the voltages which occur during operation. 
     It is advantageous for the switch disconnectors  152 ,  252 ,  352  (see  FIGS. 2   a  to  2   c ) to also already be in the transport state for all three current phases. This is because fitting of these switch disconnectors involves extensive functional tests, since they are moving parts, and these functional tests can therefore be carried out even before transportation. The fact that such moving parts no longer need be fitted and pretested on site, but that this can be done even before transportation, considerably shortens the installation time on site. 
     In order to allow a small physical height, it is advantageous for the isolating gaps of these switch disconnectors to be at least partially arranged on that side of the boundary plane  2  which faces the circuit breakers. This also contributes to keeping the physical height, that is to say the height of the transport height plane  4 , low, as described further above. 
     The transport unit  10  illustrated in  FIG. 3  takes account of these considerations, as described above, in the following manner. The transport container  13  defines an internal volume  12  with a width b and a height h, which do not exceed a width and a height of a standard container. For example, the width b is less than 2.4 m, and the height is less than 2.9 m or even less than 2.6 m. The switch bay in the transport state is accommodated in the transport container  13 . The switch bay includes the three gas-insulated circuit breaker modules  110 ,  210 ,  310  with the associated circuit breakers, which are arranged parallel to one another. Furthermore, in the transport state, the switch bay includes a switch disconnector module for each of the current phases, with a respective switch disconnector  152 ,  252 ,  352  (see  FIGS. 2   a  to  2   c ) and a busbar module  170 ,  270  for the first and the second current phases. In addition, in the transport state, the switch bay includes a busbar connection  359  for connection of a third busbar module for the third current phase. This busbar module (module  370  in  FIG. 2   c ) is, however, not connected in the transport state. 
     Further details and possible modifications of the switch disconnectors  152 ,  252 ,  352  will be described below, where such details and modifications can each be used independently of one another and can also be used in further exemplary embodiments than the described embodiment of  FIGS. 1-3  (in which case the reference symbols are only illustrative and are not limiting). The switch disconnectors each have a contact element on the circuit breaker side, and this contact element is electrically connected to the respective circuit breaker  112 ,  212  or  312 . Furthermore, the switch disconnectors each have a contact element on the busbar side, which contact element is electrically connected by means of a busbar connection conductor section  156 ,  256 ,  356  to the respective busbar phase conductor section or busbar connection  174 ,  274 , as well as  359  and  374 . 
     The contact element which is electrically connected to the circuit breaker is a moving contact element. In the switch disconnector  152 , the moving contact element is arranged on that side of the isolating gap  154  which faces away from the circuit breaker. In the switch disconnectors  252 ,  352 , the moving contact element is arranged on that side of the isolating gap  254  or  354 , respectively, which faces the circuit breaker. However, other arrangements of the moving contact element are also possible. 
     The isolating gaps  152 ,  252 ,  352  are located between the respective contact elements of the switch disconnectors  150 ,  250  and  350 . This defines an alignment of the respective isolating gap and therefore of the respective switch disconnector as the direction of the contact element on the circuit breaker side toward the contact element on the busbar side. For example, the alignment is defined by the movement direction of a moving contact piece of the switch disconnector. The isolating gaps are arranged parallel to one another, that is to say, these alignments or axes are arranged parallel to one another. This alignment can in turn define the z direction, with the z direction running transversely with respect to the x and y directions. In other words, the respective switch disconnectors  152 ,  252  and  352  are aligned in the z direction. 
     The isolating gaps  154 ,  254 ,  354  are arranged at least partially on that side of the boundary plane  2  which faces the three circuit breakers  112 ,  212 ,  312 . In accordance with an exemplary embodiment, the centers of each of the three isolating gaps  154 ,  254  and  354  are arranged on that side of the boundary plane  2  which faces the three circuit breakers  112 ,  212 ,  312 . For example, the three isolating gaps ( 154 ,  254 ,  354 ) are arranged with at least up to 70%, in a number of exemplary embodiments with at least up to 90%, of their length on that side of the boundary plane ( 2 ) which faces the three circuit breakers ( 112 ,  212 ,  312 ). 
     The first switch disconnector  154  is arranged together with the first busbar phase conductor section  174  in a first busbar module  170 . The second switch disconnector  254  is arranged together with the second busbar phase conductor section  274  in a second busbar module  270 . The third switch disconnector  354  is arranged together with the busbar connection  359  in a busbar connecting module  350 . 
     A number of other details and possible modifications of the busbar phase conductor sections and of the busbar connection will be described below, where such details and modifications can each be used independently of one another and also in further exemplary embodiments than the exemplary embodiment of  FIGS. 1-3  (in which case the reference symbols are only illustrative and not limiting): 
     The busbar phase conductor sections  174 ,  274  and if appropriate  374  each have their own housing with their own gas area for each phase. The busbar phase conductor sections  174 ,  274  and if appropriate  374  are therefore designed for single-phase encapsulation. However, they can have a common gas area for the three phases. 
     A housing section of the busbar module  170 ,  270  and/or  370  for the corresponding busbar phase conductor section  174 ,  274  or  374  is designed to be T-shaped, with the side arms of the T holding the busbar phase conductor section  174 ,  274  or  374 , and with a bottom arm of the T at least partially holding the busbar connection conductor section  156 ,  256  or  356 . 
     The first (second, third) busbar phase conductor section  174  is offset in the x direction with respect to an axis of the first (second, third) switch disconnector  152 . The first and the second busbar phase conductor sections  174 ,  274  are arranged offset with respect to one another in a z direction, which runs transversely with respect to the x and y directions. The second busbar phase conductor section  274  is arranged at least partially under (that is to say, toward the circuit breakers) the busbar connection for the third current phase  359 , in the z direction. 
     The two (and in a number of exemplary embodiments three) busbar phase conductor sections  174 ,  274  (and  374 ) run on a busbar plane  8   a  which runs in the z and y directions, for example, the two or three busbar phase conductors run on the busbar plane  8   a.    
     The first and second busbar phase conductor sections  174 ,  274  are separated from one another in the z direction by a busbar module separation, and a position which is intended for a third busbar phase conductor section  374  is separated from the second busbar phase conductor section  274  in the z direction by the busbar module separation. The position of the second busbar phase conductor section  274  has a physical height of less than 230 cm, 250 cm or 270 cm. The position which is intended for the third busbar phase conductor section  374  has a physical height of more than 230 cm, 250 cm or even 270 cm. 
     The first and second busbar phase conductor sections  174 ,  274  are arranged at a distance (between centers) d on the busbar plane  8   a,  and the physical height of the switch bay, for example, of the second busbar phase conductor section  274  and of the busbar connection  359  is less than d away from the boundary plane  2 . 
     The two busbar phase conductor modules  170 ,  270  have respective busbar flanges  172 ,  272  for connection of further sections of the busbar phase conductors in the switchgear assembly. The busbar flanges lie at least approximately on a common plane (x-z plane), within an accuracy of  50  cm. 
     The busbar connection  359  faces away from the circuit breakers  112 ,  212 ,  312 . The busbar connection  359  faces in a direction other than the y direction. The busbar connection  359 , for example, faces in a z direction which runs transversely with respect to the x and y directions, with a discrepancy of 45° or less, for example, of 10° or less. 
     The busbar connection  359  is arranged outside the busbar phase conductor for the third current phase. The busbar connection is a non-continuous outlet. 
     The busbar connection has a connecting flange which is oriented in the z direction, with the connecting flange being arranged on a plane which is parallel to the x and y directions. In addition, the busbar connection  359  has a bulkhead insulator. The bulkhead insulator is arranged on a side of the boundary plane  2  which faces away from the circuit breakers, and, in a number of exemplary embodiments, extends parallel to the boundary plane  2 . It is also possible to provide a post-type insulator instead of a bulkhead insulator. 
     The busbar is a double busbar with first busbar phase conductors (with sections  174 ,  274 ,  374 ) and second busbar phase conductors (with sections  194 ,  294 ,  394  for the first, second and third current phases, respectively). The switch bay furthermore includes: in each case, one T-like connection piece  140 ,  240 ,  340  for the first, second and third current phases, each with a bottom outlet, a first side outlet and a second side outlet which is opposite the first side outlet, wherein each of the three connection pieces  140 ,  240 ,  340  can be connected via the respective bottom outlet to the circuit breaker  112 ,  212 ,  312 , via the respective first side outlet to the first busbar phase conductor section  174 ,  274 ,  374 , and via the respective second side outlet to the second busbar phase conductor section  194 ,  294 ,  394  of the respective current phase. 
     The first side outlets (e.g., their centers) of all three T-like connection pieces are arranged along a first straight line, and the second side outlets (e.g., their centers) are arranged along a second straight line, with the first (and the second) straight line running along the y direction, in a number of exemplary embodiments. 
     In a number of exemplary embodiments, each of the three connection pieces has a respective node point, from which electrical conductor sections  145 ,  146 ;  245 ,  246 ;  345 ,  346  extend like a star to the respective side outlets and to the respective bottom outlet, and the node points of all three T-like connection pieces run along a third straight line, which runs along the y direction in a number of embodiments. 
     The switch bay has a first busbar module  170  and a second busbar module  270 , with the first busbar phase conductor section  174  being arranged in the first busbar module  170 , and the second busbar phase conductor section  274  being arranged in the second busbar module  270 . The busbar connection  359  is designed for connection of a third busbar phase conductor section  374  for the third current phase such that a third busbar module  370  of the third current phase can be formed, in which third busbar module  370  the third busbar phase conductor section  374  is arranged. 
     Furthermore, the switch bay has a third busbar phase conductor section  374  for the third current phase. The third busbar phase conductor section  374  is arranged parallel to the first and to the second busbar phase conductor sections  174 ,  274 , is connected to the busbar connection  359 , and/or can be electrically connected to the circuit breaker for the third current phase  312  via the switch disconnector of the third current phase  354 . 
     The third busbar section is offset away from the circuit breakers in a z direction, for example, by the distance d, in comparison to the first and the second busbar sections. In a number of exemplary embodiments, the three busbar phase conductor sections run on the busbar plane  8   a,  and are separated uniformly from one another. 
     The busbar phase conductor sections  174 ,  274  and  374  can in modified exemplary embodiments also be arranged differently than on a planar busbar surface  8   a.  By way of example, they can, for example, be arranged on a cylinder surface (circle segment in  FIG. 8   a ) or in an L-like configuration, with the sections  174  and  274  being arranged offset essentially in the x direction with respect to one another, and with the section  374  being offset in the z direction with respect to them. 
     A number of further details and possible modifications of the switch bay will be described below. According to an exemplary embodiment, the switch bay is pretested, that is to say it has already been brought to a state in which it is substantially ready to operate, and is subjected to a number of functional tests in this state. The switch bay is filled with inert gas, for example, at a gas pressure of more than 1 bar, such as at least 1.5 bar. The switch bay is arranged such that it can be transported in a container. The switch bay is designed for an operating voltage of at least 400 kV, for example 420 kV. The switch bay includes three grounding switches, one for each of the three current phases, with the grounding switches being accommodated, for example, in the switch disconnector modules  150 ,  250 ,  350 , or else with the capability to be accommodated in the connection modules  140 ,  240 ,  340 . The switch bay includes current transformers and/or voltmeters. 
     A method for installation of a high-voltage switchgear assembly will be described below. In this case, the installation process also includes those activities such as production, upgrading, repair, etc. 
     First of all, a preassembled switch bay is provided in a standardized transport container. This is done physically remotely from an installation location for the high-voltage switchgear assembly. For example, the switch bay can be the switch bay shown in  FIG. 3 , having a first busbar phase conductor section  174  of the first current phase and a second busbar phase conductor section  274  of the second current phase (see also  FIGS. 1 to 2   c ). In the transport state, the switch bay, and in particular the busbar phase conductor sections for the first and the second of the current phases and a busbar connection  359  for the third current phase of the switch bay, has a physical height which is less than the internal height of the transport container. Functional pretesting of the switch bay can optionally be carried out before transportation. 
     The switch bay is then transported in the transport container to the installation location for the high-voltage switchgear assembly. In a number of embodiments, the switch bay is at least partially filled with inert gas while being transported. 
     A third busbar phase conductor section of the third current phase is then connected to the busbar connection of the switch bay, as a result of which the busbar phase conductor section of the third current phase has a physical height which is greater than an internal height of the transport container. By way of example, this makes it possible to produce the switch bay illustrated in  FIG. 1 . In a number of embodiments, the first, second and/or third busbar phase conductor sections are then connected to further sections of the busbar phase conductors in the switchgear assembly. This results in a high-voltage switchgear assembly having a switch bay as described herein. 
     Optionally, the switch bay can remain in the transport container while being connected, that is to say at least the circuit breakers and the switch disconnectors remain in the transport container. 
     It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.