Automatic synchroniser

Abstract

A device to achieve synchronisation of an alternator with a running power source. Power systems usually comprise a number of alternator units operated in parallel to supply common busbars. This arrangement offers multifield advantages, in that: (a) the number of alternators in service at any particular time can be adjusted compatibly with the load demand, and thus the machines will be operated in the high efficiency region. (b) the margin between the "total" and "firm" capacities, is reduced thus restricting capital investment in spare plant. (c) individual machines can be taken out of service without substantial impact on system capacity. (d) additional machine; can be added to cope with load demand growth and system expansion. Before an alternator can be successfully connected to common busbars which are energised by other machines in operation the following set of conditions must be satisfied:- (1) the voltage and phase sequence of the incoming machine must be identical to that of the running sets. (2) the frequency of the incoming machine must be identical to that of the busbars. (3) the phase angle relationship must be zero; both the incoming machine and the sets in operation must be running in phase. [...]