SWITCHING EQUIPMENT 



573 



switching stations of this kind are in successful operation, and, 

 while the practice has only been in connection with a few generat- 

 ing stations, the results obtained from these installations have 

 clearly demonstrated the practicability of such a design. Notable 

 among such systems is that of the Utah Light & Power Company. 

 The high-tension buses and connections together with the dis- 

 connecting switches, choke coils, lightning-arrester horn gaps, etc., 

 are generally mounted on steel structures or trusses supported on 

 towers, the layout being governed by the equipment and the 

 method of control which has been adopted. The line wires 

 should be securely anchored before entering the station structure 



FIG. 364. Typical High-voltage Bus and Switch Structure. 



and no unnecessary strains should be permitted in the wires inside 

 the structure. Consideration should be given to deflections 

 resulting from different pulls on the connections and also to un- 

 equal settlement of supporting towers, which may readily cause 

 excessive stresses and insulator breakages, resulting in service 

 interruptions. The spacing of all the conductors, as well as that 

 of apparatus should be liberal but not large. 



The oil circuit breakers and transformers are generally located 

 on the ground, the oil circuit breakers being placed below the dis- 

 connecting switches. It is often desirable to provide some sort 

 of housing or roofing for partially protecting the oil circuit break- 



