Spare transformer connecting means

Abstract

Discloses a power system in which three single phase transformers have their primary windings connected in delta to a 3-phase isolated phase bus. Switching means is provided for connecting a spare transformer to said bus as a replacement for any one of said single phase transformers. Special interlocking means assures that the spare transformer is connected to the bus in the same manner as the transformer it replaces. .Iadd.

What I claim as new and desired to secure by letters Patent of the United States is: .[.1. In an electric power system that comprises: (1) a three-phase isolated phase bus comprising first, second, and third main bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to said bus as a replacement for any one of said three single-phase transformers, comprising: 
     
        taken from one of said normally-closed disconnect devices..]. 5. .[.The combination as defined in claim 1 in further combination with:.]. .Iadd.In an electric power system that comprises: (1) a three-phase isolated phase bus comprising first, second, and third main bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to said bus as a replacement for any one of said three single-phase trasnsformers, comprising: (a) first and second auxiliary bus bars, respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) three normally-open disconnect devices, the first being electrically connected between the first of said main bus bars and said first auxiliary bus bar, the second being electrically connected between the second of said main bus bars and said first auxiliary bus bar, and the third being electrically connected between the third of said main bus bars and said first auxiliary bus bar,   (c) three additional normally-open disconnect devices, the first additional normally-open disconnect device being electrically connected between the first of said main bus bars and said second auxiliary bus bar, the second additional normally-open disconnect device being electrically between the second of said main bus bars and said second auxiliary bus bar, the third additional normally-open disconnect device being electrically between the third of said main bus bars and said second auxiliary bus bar,   (d) replacement of any one of said single phase transformers by said spare being effected by opening the two normally-closed disconnect devices connecting said one single phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the spare to said given pair of main bus bars, and   (e) interlock means requiring (i) opening of the normally-closed disconnect device connected between a given one of said main bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to (ii) the closing of the normally-open disconnect device located between said given bus bar and the corresponding polarity terminal of the spare transformer connected thereto upon said closing, and in further combination with the above-recited combination: .Iaddend.   .[.(a).]. .Iadd.(f) .Iaddend.a plurality of metal housings at ground potential respectively surrounding each of said main bus bars,   .[.(b).]. .Iadd.(g) .Iaddend.the metal housing surrounding a given bus bar also having a portion surrounding the disconnect devices connected thereto,   .[.(c).]. .Iadd.(h) .Iaddend.access openings in said housings respectively located opposite the disconnect devices therein,   .[.(d).]. .Iadd.(i) .Iaddend.covers for each of said access openings,   .[.(e).]. .Iadd.(j) .Iaddend.locks for each of said covers normally locking said cover on its associated opening,   .[.(f).]. .Iadd.(k) .Iaddend.a key for each of the locks of a cover opposite a normally-closed disconnect device,   .[.(g).]. .Iadd.(l) .Iaddend.key interlock means preventing the key used for unlocking a cover opposite a given normally-closed disconnect device from unlocking any of the covers of said normally-open disconnect devices except the cover of the particular normally-open disconnect device which, upon closing, connects a spare transformer to the same bus bar as the bus bar to which said given normally-closed disconnect device connected its   
     
     
        transformer terminal. 6. .[.The combination of claim 1 in which:.]. .Iadd.In an electric power system that comprises: (1) a three-phase isolated phase bus comprising first, second, and third main bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to said bus as a replacement for any one of said three single-phase transformers, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) three normally-open disconnect devices, the first being electrically connected between the first of said main bus bars and said first auxiliary bus bar, the second being electrically connected between the second of said main bus bars and said first auxiliary bus bar, and the third being electrically connected between the third of said main bus bars and said first auxiliary bus bar,   (c) three additional normally-open disconnect devices, the first additional normally-open disconnect device being electrically connected between the first of said main bus bars and said second auxiliary bus bar, the second additional normally-open disconnect device being electrically between the second of said main bus bars and said second auxiliary bus bar, the third additional normally-open disconnect device being electrically between the third of said main bus bars and said second auxiliary bus bar,   (d) replacement of any one of said single phase transformers by said spare being effected by opening the two normally-closed disconnect devices connecting said one single phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the spare to said given pair of main bus bars, and   (e) interlock means requiring (i) opening of the normally-closed disconnect device connected between a given one of said main bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to (ii) the closing of the normally-open disconnect device located between said given bus bar and the corresponding polarity terminal of the spare transformer connected thereto upon said closing, .Iaddend.   .[.(a).]. .Iadd.(f) .Iaddend.each of said normally-closed disconnect devices comprises a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   .[.(b).]. .Iadd.(g) .Iaddend.each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   .[.(c).]. .Iadd.(h) .Iaddend.a removable barrier is present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   .[.(d).]. .Iadd.(i) .Iaddend.said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   .[.(e).]. .Iadd.(j) .Iaddend.said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then-opened, disconnect device being spaced from the terminal members of said latter disconnect device. .[.7. The electric power system of claim 2 in combination with:   (a) a third three phase bus comprising first, second and third main bus bars,   (b) three additional single-phase transformers normally having their primary windings connected in delta to said third three-phase bus,   (c) means for connecting the single-phase transformer of said power system located adjacent said third three-phase bus to said third three-phase bus as a replacement for any one of the additional single phase transformers normally connected to said third three-phase bus, comprising: (i) three further normally-open disconnect devices respectively connected between one terminal of said adjacent transformer and said first, second and third main bus bars of said third bus,   (ii) three still further normally-open disconnect devices respectively connected between the opposite terminal of said adjacent transformer and said first, second and third main bus bars of said third bus,   (iii) a pair of normally-closed disconnect devices for each of the single-phase transformers normally connected to said third bus respectively connected between terminals of said latter single phase transformer and the main bus bars to which said latter single phase transformer is connected,   (iv) replacement of said latter single-phase transformer by said adjacent transformer being effected by opening the two normally-closed disconnect devices connecting said latter single-phase transformer to a given pair of main bus bars in said third bus and closing the two normally-open disconnect devices of those recited in (i) and (ii) that, upon closing, connect said spare transformer to said given pair of main bus bars in said     
     
     
        third bus..]. 8. The arrangement of claim .[.7.]. .Iadd.26 .Iaddend.in combination with: interlock means requiring opening of the normally-closed disconnect device connected between a given one of the main bus bars of said third bus and the terminal normally connected thereto of the single phase transformer being replaced as a requisite to the closing of the disconnect device located between said given bus bar of the third bus and the corresponding polarity terminal of said adjacent transformer connected thereto upon said closing. .[.9. In an electric power system that comprises: (1) a three-phase isolated-phase bus comprising first, second and third bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices or each pair being between the terminals of the associated primary windings and the bus bars to which their terminals are respectively connected and, (4) a spare transformer having a primary winding with a pair of terminals, means for connecting said spare transformer to said bus when one of said three single-phase transformers is disconnected therefrom, comprising: (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars, the second two being electrically connected respectively between the terminals of one of said four transformers and the first and second of said bus bars, the third two being electrically connected respectively between the terminals of one of said four transformers and the second and third of said bus bars,   (b) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect the associated transformer to the same bus bars as said disconnected transformer was connected to..]. .[.10. In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second, and third bus bars, (2) six single-phase tranformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the bus bars to which said terminals are respectively connected, and (4) a spare tranformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses when one of said thre single-phase transformers normally connected thereto is disconnected therefrom, comprising:   (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of one of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said one bus and the first and second of the main bus bars of said one bus, the third two being electrically connected respectively between the terminals of one of said four transformers connectable to said one bus and the second and third of the main bus bars of said one bus,   (b) six additional normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of the other of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said other bus and the first and second of the bus bars of said other bus, the third two being electrically connected respectively between the terminals of one of said latter four transformers and the second and third of the bus bars of said other bus,   (c) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect their associated transformer to the same bus bars as said disconnected transformer was connected to..]. .[.11. The arrangement of claim 9 in combination with interlock means requiring:   (i) opening of the normally-closed disconnect device connected between a given one of said bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to   (ii) closing of the normally-open disconnect device located between said given bus bar and the terminal of the replacement transformer connected   
     
     
        thereto upon said closing..]. .[.12.  The combination as defined in claim 9 in which: (a) each of said normally-closed disconnect devices comprises a pair of spaced-apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) and each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link   
     
     
        taken from one of said normally-closed disconnect devices..]. 13. .[.The combination as defined in claim 9 in which:.]. .Iadd.In an electric power system that comprises: (1) a three-phase isolated-phase bus comprising first, second and third bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary windings and the bus bars to which their terminals are respectively connected and, (4) a spare transformer having a primary winding with a pair of terminals, means for connecting said spare transformer to said bus when one of said three single-phase tranformers is disconnected therefrom, comprising: (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars, the second two being electrically connected respectively between the terminals of one of said four transformers and the first and second of said bus bars, the third two being electrically connected respectively between the terminals of one of said four transformers and the second and third of said bus bars,   (b) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect the associated transformer to the same bus bars as said disconnected transformer was connected to, .Iaddend.   .[.(a).]. .Iadd.(c) .Iaddend.each of said normally-closed disconnect devices comprises a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   .[.(b).]. .Iadd.(d) .Iaddend.each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   .[.(c).]. .Iadd.(e) .Iaddend.a removable barrier is present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   .[.(d).]. .Iadd.(f) .Iaddend.said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   .[.(e).]. .Iadd.(g) .Iaddend.said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then opened, disconnect device being spaced from the terminal members of said latter .[.dis-combination   
     
     
        with:.]. .Iadd.disconnect device. .Iaddend. 14. .[.The electric power system of claim 1, in combination with:.]. .Iadd.In an electric power system that comprises: (1) a three-phase isolated phase bus comprising first, second, and third main bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to said bus as a replacement for any one of said three single-phase transformers, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) three normally-open disconnect devices, the first being electrically connected between the first of said main bus bars and said first auxiliary bus bar, the second being electrically connected between the second of said main bus bars and said first auxiliary bus bar, and the third being electrically connected between the third of said main bus bars and said first auxiliary bus bar,   (c) three additional normally-open disconnect devices, the first additional normally-open disconnect device being electrically connected between the first of said main bus bars and said second auxiliary bus bar, the second additional normally-open disconnect device being electrically between the second of said main bus bars and said second auxiliary bus bar, the third additional normally-open disconnect device being electrically between the third of said main bus bars and said second auxiliary bus bar,   replacement of any one of said single phase transformers by said spare being effected by opening the two normally-closed disconnect devices connecting said one single phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the spare to said given pair of main bus bars, and   (e) interlock means requiring (i) opening of the normally-closed disconnect device connected between a given one of said main bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to (ii) the closing of the normally-open disconnect device located between said given bus bar and the corresponding polarity terminal of the spare transformer connected thereto upon said closing, and in further combination with said electric power system as recited hereinabove:   .[.(a).]. .Iadd.(f) .Iaddend.a plurality of housings at ground potential respectively surrounding each of said main bus bars,   .[.(b).]. .Iadd.(g) .Iaddend.cooling means for causing a flow of cooling fluid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   .[.(c).]. .Iadd.(h) .Iaddend.the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   .[.(d).]. .Iadd.(i) .Iaddend.a removable barrier associated with each disconnect device when it is in open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   .[.(e).]. .Iadd.(j) .Iaddend.means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect device without interference from the   
     
     
        barrier. .[.15.  The combination as defined in claim 2 in which: (a) each of said normally-closed disconnect devices comprises a pair of spaced-apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) and each of said normally-open disconnect devices comprises a pair of spaced apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices..]. .[.16. The combination as defined in claim 3 in which:   (a) each of said normally-closed disconnect devices comprises a pair of spaced-apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) and each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link   
     
     
        taken from one of said normally-closed disconnect devices..]. .[.17.  The combination as defined in claim 2 in further combination with: (a) a plurality of metal housings at ground potential respectively surrounding each of said main bus bars,   (b) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect devices connected thereto,   (c) access openings in said housings respectively located opposite the disconnect devices therein,   (d) covers for each of said access openings,   (e) locks for each of said cover normally locking said cover on its associated opening,   (f) a key for each of the locks of a cover opposite a normally-closed disconnect device,   (g) key interlock means preventing the key used for unlocking a cover opposite a given normally-closed disconnect device from unlocking any of the covers of said normally-open disconnect devices except the cover of the particular normally-open disconnect device which, upon closing, connects a spare transformer  to the same bus bar as the bus bar to which said given normally-closed disconnect device connected its transformer terminal..]. .[.18. The combination as defined in claim 3 in further combination with:   (a) a plurality of metal housings at ground potential respectively surrounding each of said main bus bars,   (b) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect devices connected thereto,   (c) access openings in said housings respectively located opposite the disconnect devices therein,   (d) covers for each of said access openings,   (e) locks for each of said covers normally locking said cover on its associated opening,   (f) a key for each of the locks of a cover opposite a normally-closed disconnect device,   (g) key interlock means preventing the key used for unlocking a cover opposite a given normally-closed disconnect device from unlocking any of the covers of said normally-open disconnect devices except the cover of the particular normally-open disconnect device which, upon closing, connects a spare transformer to the same bus bar as the bus bar to which said given normally-closed disconnect device connected its tranformer terminal..]. .[.19. The combination as defined in claim 3 in further combination with:   (a) each of said normally-closed disconnect devices comprises a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   (c) a removable barrier is present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   (d) said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   (e) said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then-opened, disconnect device being spaced from the terminal members of said latter disconnect device..]. .[.20. The arrangement of claim 10 in combination with interlock means requiring:   (i) opening of the normally-closed disconnect device connected between a given one of said bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to   (ii) closing of the normally-open disconnect device located between said given bus bar and the terminal of the replacement transformer connected thereto upon said closing..]. .[.21. The combination as defined in claim 10 in which:   (a) each of said normally-closed disconnect devices comprises a pair of a spaced-apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) and each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices..]. .[.22. The combination as defined in claim 10 in which:   (a) each of said normally-closed disconnect devices comprises a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (b) each of said normally-open disconnect devices comprises a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   (c) a removable barrier is present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   (d) said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   (e) said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then opened, disconnect device being spaced from the terminal members of said latter disconnect device..]. .[.23. The electric power system of claim 2 in combination with:   (a) a plurality of housings at ground potential respectively surrounding each of said main bus bars,   (b) bus cooling means for causing a flow of cooling fluid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   (c) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   (d) a removable barrier associated with each disconnect device when it is open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   (e) means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect   
     
     
        device without interference from the barrier..]. 24. .[.The electric power system of claim 9 in combination with:.]. .Iadd.In an electric power system that comprises: (1) a three-phase isolated-phase bus comprising first, second and third bus bars, (2) three single-phase transformers each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting said three primary windings in delta to said bus, the normally-closed disconnect devices of each pair being between the terminals of the associated primary windings and the bus bars to which their terminals are respectively connected and, (4) a spare transformer having a primary winding with a pair of terminals, means for connecting said spare transformer to said bus when one of said three single-phase transformers is disconnected therefrom, comprising: (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars, the second two being electrically connected respectively between the terminals of one of said four transformers and the first and second of said bus bars, the third two being electrically connected respectively between the terminals of one of said four transformers and the second and third of said bus bars,   (b) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect the associated transformer to the same bus bars as said disconnected transformer was connected to, and in further combination with said electric power system as recited hereinabove: .Iaddend.   .[.(a).]. .Iadd.(c) .Iaddend.a plurality of housings at ground potential respectively surrounding each of said main bus bars,   .[.(b).]. .Iadd.(d) .Iaddend.bus cooling means for causing a flow of cooling fluid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   .[.(c).]. .Iadd.(e) .Iaddend.the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   .[.(d).]. .Iadd.(f) .Iaddend.a removable barrier associated with each disconnect device when it is in open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   .[.(e).]. .Iadd.(g) .Iaddend.means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect device without interference from the   
     
     
        barrier. .[.25.  The electrical power system of claim 10 in combination with: (a) a plurality of housings at ground potential respectively surrounding each of said main bus bars,   (b) bus cooling means for causing a flow of cooling liquid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   (c) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   (d) a removable barrier associated with each disconnect device when it is in open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   (e) means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect   
     
     
        device without interference from the barrier..]. .Iadd. 26.  In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second and third main bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses as a replacement for any one of the three single-phase transformers normally connected thereto, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) six normally-open disconnect devices, the first two of which are respectively electrically connected between said first auxiliary bus and the first of the main bus bars of said two buses, the second two of which are respectively electrically connected between said first auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically connected between said first auxiliary bus and the third of the main bus bars of said two buses,   (c) six additional normally-open disconnect devices, the first two of which are respectively electrically between said second auxiliary bus bar and the first of the main bus bars of said two buses, the second two of which are respectively electrically between said second auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically between said second auxiliary bus bar and the third of the main bus bars of said two buses,   (d) replacement of any one of said single-phase transformers by said spare transformer being effected by opening the two normally-closed disconnect devices connecting the primary winding of said one single-phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the primary winding of said spare transformer to said given pair of main bus bars,   (e) a third three phase bus comprising first, second and third main bus bars,   (f) three additional single-phase transformers normally having their primary windings connected in delta to said third three-phase bus,   (g) means for connecting the single-phase transformer of said power system located adjacent said third three-phase bus to said third three-phase bus as a replacement for any one of the additional single phase transformers normally connected to said third three-phase bus, comprising: (i) three further normally-open disconnect devices respectively connected between one terminal of said adjacent transformer and said first, second and third main bus bars of said third bus,   (ii) three still further normally-open disconnect devices respectively connected between the opposite terminal of said adjacent transformer and said first, second and third main bus bars of said third bus,   (iii) a pair of normally-closed disconnect devices for each of the single-phase transformers normally connected to said third bus respectively connected between terminals of said latter single phase transformer and the main bus bars to which said latter single phase transformer is connected,   (iv) replacement of said latter single-phase transformer by said adjacent transformer being effected by opening the two normally-closed disconnect devices connecting said latter single-phase transformer to a given pair of main bus bars in said third bus and closing the two normally-open disconnect devices of those recited in (i) and (ii) that, upon closing, connect said spare transformer to said given pair of main bus bars in said     
     
     
        third bus. .Iaddend..Iadd. 27.  In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second and third main bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses as a replacement for any one of the three single-phase transformers normally connected thereto, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) six normally-open disconnect devices, the first two of which are respectively electrically connected between said first auxiliary bus and the first of the main bus bars of said two buses, the second two of which are respectively electrically connected between said first auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically connected between said first auxiliary bus and the third of the main bus bars of said two buses,   (c) six additional normally-open disconnect devices, the first two of which are respectively electrically between said second auxiliary bus bar and the first of the main bus bars of said two buses, the second two of which are respectively electrically between said second auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically between said second auxiliary bus bar and the third of the main bus bars of said two buses,   (d) replacement of any one of said single-phase transformers by said spare transformer being effected by opening the two normally-closed disconnect devices connecting the primary winding of said one single-phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the primary winding of said spare transformer to said given pair of main bus bars,   (e) a plurality of metal housings at ground potential respectively surrounding each of said main bus bars,   (f) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect devices connected thereto,   (g) access openings in said housings respectively located opposite the disconnect devices therein,   (h) covers for each of said access openings,   (i) locks for each of said covers normally locking said cover on its associated opening,   (j) a key for each of the locks of a cover opposite a normally-closed disconnect device,   (k) key interlock means preventing the key used for unlocking a cover opposite a given normally-closed disconnect device from unlocking any of the covers of said normally-open disconnect devices except the cover of the particular normally-open disconnect device which, upon closing, connects a spare transformer to the same bus bar as the bus bar to which said given normally-closed disconnect device connected its transformer   
     
     
        terminal. .Iaddend..Iadd. 28.  In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second and third main bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses as a replacement for any one of the three single-phase transformers normally connected thereto, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) six normally-open disconnect devices, the first two of which are respectively electrically connected between said first auxiliary bus and the first of the main bus bars of said two buses, the second two of which are respectively electrically connected between said first auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically connected between said first auxiliary bus and the third of the main bus bars of said two buses,   (c) six additional normally-open disconnect devices, the first two of which are respectively electrically between said second auxiliary bus bar and the first of the main bus bars of said two buses, the second two of which are respectively electrically between said second auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically between said second auxiliary bus bar and the third of the main bus bars of said two buses,   (d) replacement of any one of said single-phase transformers by said spare transformer being effected by opening the two normally-closed disconnect devices connecting the primary winding of said one single-phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the primary winding of said spare transformer to said given pair of main bus bars,   (e) interlock means requiring: (i) opening of the normally-closed disconnect device connected between a given one of said main bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to (ii) closing of the normally-open disconnect device located between said given main bus bar and the corresponding polarity terminal of the spare transformer connected thereto upon said closing,   (f) a plurality of metal housings at ground potential respectively surrounding each of said main bus bars,   (g) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect devices connected thereto,   (h) access openings in said housing respectively located opposite the disconnect devices therein,   (i) covers for each of said access openings,   (j) locks for each of said covers normally locking said cover on its associated opening,   (k) a key for each of the locks of a cover opposite a normally-closed disconnect device,   (l) key interlock means preventing the key used for unlocking a cover opposite a given normally-closed disconnect device from unlocking any of the covers of said normally-open disconnect devices except the cover of the particular normally-open disconnect device which, upon closing, connects a spare transformer to the same bus bar as the bus bar to which said given normally-closed disconnect device connected its transformer   
     
     
        terminal. .Iaddend. .Iadd. 29.  In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second and third main bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses as a replacement for any one of the three single-phase transformers normally connected thereto, comprising: (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) six normally-open disconnect devices, the first two of which are respectively electrically connected between said first auxiliary bus and the first of the main bus bars of said two buses, the second two of which are respectively electrically connected between said first auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically connected between said first auxiliary bus and the third of the main bus bars of said two buses,   (c) six additional normally-open disconnect devices, the first two of which are respectively electrically between said second auxiliary bus bar and the first of the main bus bars of said two buses, the second two of which are respectively electrically between said second auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically between said second auxiliary bus bar and the third of the main bus bars of said two buses,   (d) replacement of any one of said single-phase transformers by said spare transformer being effected by opening the two normally-closed disconnect devices connecting the primary winding of said one single-phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the primary winding of said spare transformer to said given pair of main bus bars,   (e) interlock means requiring: (i) opening of the normally-closed disconnect device connected between a given one of said main bus bars and the terminal connected thereto of the single phase transformer that is being replaced, as a requisite to (ii) closing of the normally-open disconnect device located between said given main bus bar and the corresponding polarity terminal of the spare transformer connected thereto upon said closing,   (f) each of said normally-closed disconnect devices comprising a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (g) each of said normally-open disconnect devices comprising a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   (h) a removable barrier present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   (i) said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   (j) said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then-opened, disconnect device being spaced from the terminal members of said latter disconnect device. .Iaddend..Iadd. 30. In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second, and third bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the bus bars to which said terminals are respectively connected, and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses when one of said three single-phase transformers normally connected thereto is disconnected therefrom, comprising:   (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of one of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said one bus and the first and second of the main bus bars of said one bus, the third two being electrically connected respectively between the terminals of one of said four transformers connectable to said one bus and the second and third of the main bus bars of said one bus,   (b) six additional normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of the other of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said other bus and the first and second of the bus bars of said other bus, the third two being electrically connected respectively between the terminals of one of said latter four transformers and the second and third of the bus bars of said other bus,   (c) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect their associated transformer to the same bus bars as said disconnected transformer was connected to,   (d) each of said normally-closed disconnect devices comprising a pair of spaced apart terminal members and a removable disconnect link connected therebetween, said disconnect link being removable to effect opening of said normally-closed disconnect device,   (e) each of said normally-open disconnect devices comprising a pair of spaced-apart terminal members which are normally electrically isolated from each other but are adapted to receive therebetween a disconnect link taken from one of said normally-closed disconnect devices,   (f) a removable barrier present between the terminal members of each of said normally-open disconnect devices when open, said barrier being located in spaced-apart relationship to said terminal members,   (g) said barrier requiring removal as a prerequisite to connection of a disconnect link between said terminal members during a closing operation of said normally-open disconnect device, and   (h) said removed barrier fitting into the normally-closed disconnect device that has been opened to provide a disconnect link for said closing operation, said barrier upon being included in said normally-closed, but then opened, disconnect device being spaced from the terminal members of said latter disconnect device. .Iaddend..Iadd. 31. In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second and third main bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the main bus bars to which said terminals are respectively connected and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses as a replacement for any one of the three single-phase transformers normally connected thereto, comprising:   (a) first and second auxiliary bus bars respectively connected to the opposite terminals of the primary winding of said spare transformer,   (b) six normally-open disconnect devices, the first two of which are respectively electrically connected between said first auxiliary bus and the first of the main bus bars of said two buses, the second two of which are respectively electrically connected between said first auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically connected between said first auxiliary bus and the third of the main bus bars of said two buses,   (c) six additional normally-open disconnect devices, the first two of which are respectively electrically between said second auxiliary bus bar and the first of the main bus bars of said two buses, the second two of which are respectively electrically between said second auxiliary bus bar and the second of the main bus bars of said two buses, the third two of which are respectively electrically between said second auxiliary bus bar and the third of the main bus bars of said two buses,   (d) replacement of any one of said single-phase transformers by said spare transformer being effected by opening the two normally-closed disconnect devices connecting the primary winding of said one single-phase transformer to a given pair of main bus bars and closing the two normally-open disconnect devices that, upon closing, connect the primary winding of said spare transformer to said given pair of main bus bars,   (e) a plurality of housings at ground potential respectively surrounding each of said main bus bars,   (f) bus cooling means for causing a flow of cooling fluid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   (g) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   (h) a removable barrier associated with each disconnect device when it is open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   (i) means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect device without interference from the barrier. .Iaddend. .Iadd. 32. In an electric power system that comprises (1) two three-phase isolated phase buses, each comprising first, second, and third bus bars, (2) six single-phase transformers, each having a primary winding with a pair of terminals, (3) a pair of normally-closed disconnect devices for each of said primary windings connecting three of said windings in delta to one of said buses and the other three of said primary windings in delta to the other of said buses, the normally-closed disconnect devices of each pair being between the terminals of the associated primary winding and the bus bars to which said terminals are respectively connected, and (4) a spare transformer having a primary winding with a pair of terminals; means for connecting said spare transformer to either of said buses when one of said three single-phase transformers normally connected thereto is disconnected therefrom, comprising:   (a) six normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of one of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said one bus and the first and second of the main bus bars of said one bus, the third two being electrically connected respectively between the terminals of one of said four transformers connectable to said one bus and the second and third of the main bus bars of said one bus,   (b) six additional normally-open disconnect devices, the first two being electrically connected respectively between the terminals of said spare transformer and the first and third bus bars of the other of said buses, the second two being electrically connected respectively between the terminals of one of the four transformers connectable to said other bus and the first and second of the bus bars of said other bus, the third two being electrically connected respectively between the terminals of one of said latter four transformers and the second and third of the bus bars of said other bus,   (c) replacement of a disconnected transformer being effected by closing the two normally-open disconnect devices that, upon closing, connect their associated transformer to the same bus bars as said disconnected transformer was connected to,   (d) a plurality of housings at ground potential respectively surrounding each of said main bus bars,   (e) bus cooling means for causing a flow of cooling fluid to flow through said housings along the surrounded bus bar toward any transformer connected to said bus bar,   (f) the metal housing surrounding a given bus bar also having a portion surrounding the disconnect device connected thereto,   (g) a removable barrier associated with each disconnect device when it is in open position for blocking the flow of gas past said open disconnect device toward the transformer to which said open disconnect device is connected, and   (h) means requiring removal of the barrier associated with a given open disconnect device as a prerequisite to closing of said open disconnect device, thus permitting cooling gas to flow past a closed disconnect device without interference from the barrier.