Hi Robert, Chilli, Chippie, Russlk, Phasor,
The switching of these in and out is not usually a simple matter.
It is not clear what type of breakers are being used, or if the
switching is automated or just the synch and closing is automated
or if the synch and closing is done by the operator.
If the equipment is older stuff thats being pressed into service
its probably all operator controlled, but if its newer stuff then
it could be almost all automatic.
The load can vary a lot quite quickly, winding some sort of dummy
load up and down to compensate is the normal way that such a
power station as described by Robert would operate.
The operator might have a console on which to instruct the levels
of load that different generators cut in or out,
Or if its more hands-on the operator would optimise the situation
as he sees fit, with manual switching. Switching generators in and
out requires practise and understanding of the synch and power
factor systems and controls. Doing it wrong could cause a lot of
damage, and maybe injury. Later systems would have safeguards.
Many larger 3ph breakers have operation counters attached because
they have to be serviced after a number of operations.
One advantage of an electrode type boiler used as a load is that
the breaker feeding it may mostly be left in the 'ON' position as
when the electrodes are wound up out of the water, the load is
removed.
If such a unit had to be made on-site, the construction could be
as simple as a winding assembly to raise and lower conductors on
guides into and out of a water container, suitable precautions as
to insulation.
Older breakers were not made for frequent or hourly use, newer ones
probably can cope with more frequent use, but it would not be
normal to shuffle generators around to optimise loading in this
situation. Those diesel units are intended for long running at
fairly steady loads at or near 85 - 90 per cent of their maximum.
Regards John