ABSTRACT
Buses exist throughout the power system and, particularly, wherever two or
more circuits are interconnected. The number of circuits that are connected to
a bus varies widely. Bus faults can result in severe system disturbances, as
high fault current levels are typically available at bus locations and because
all circuits supplying fault current must be opened to isolate the problem.
Thus, when there are more than six to eight circuits involved, buses are often
split by a circuit breaker (bus tie), or a bus arrangement is used that minimizes
the number of circuits, which must be opened for a bus fault. There are many
bus arrangements in service dictated by the foregoing and by the economics
and flexibility of system operation. The major types are illustrated in Figure
10.1 through Figure 10.8. Four circuits for each bus have been chosen
arbitrarily for convenience and comparison. The bus circuit breakers usually
have disconnect switches on either side, as shown, to provide means of
isolating them from the system after trouble or for maintenance. Generally,
these switches are operated manually at no load. The circuits shown connect-
ing to the buses can be generators, transformers, lines, motors, and so on.
