Basler BE1-25A Instruction Manual - Application
BE1-25A
APPLICATION
3
The basic BE1-25A synchronizer, without any options,
may be used to close the breaker between a generator
and bus when the generator frequency and phase angle
are within prescribed limits.
A voltage acceptance option (A1 or A2) may be added
to permit breaker closing only if the generator and bus
voltages are within preset limits.
The frequency (F5) and voltage matching (V1, V2, V3)
options provide outputs for automatically adjusting the
prime mover governor and generator voltage controls as
necessary to achieve automatic synchronization and
closure of the breaker.
The Dead Bus option (D1) may be added to close the
breaker when the bus voltage is less than the value set
on the Dead Bus Module control regardless of generator
speed. In practice, this function is controlled by the
operator and is enabled by closing a switch across the
terminals labeled Dead Bus Control Switch.
Emergency standby generating systems require the lead
generator to automatically close into a dead bus without
concern for synchronization. The BE1-25A has available
an optional dead bus feature that allows immediate
closure under this circumstance.
MULTI-GENERATOR OPERATION
The BE1-25A automatic synchronizer can be used on
multiple-generator systems by switching the generator
sensing voltage and the breaker closing circuit simulta-
neously to the desired generator. The closing param-
eters for each different generator/breaker are recalled
from nonvolatile memory and used to calculate the
closing conditions for the particular breaker. If all
generators/breakers have the same parameters, the
default set can be used and no selection is necessary.
BUS-TO-BUS APPLICATION
Some transmission circuits, when split apart, assume a
phase angle difference that stabilizes as a steady state
offset. When this occurs, it is possible to reclose by
supervisory means (usually supervised by a sync-
check relay) if the angle is small enough and the shock
to the system can be tolerated. Other circuits, however,
may exhibit a frequency slip with respect to each other
when split apart.
The BE1-25A can be used in a bus-to-bus application
if either of the following conditions is met:
1.
The slip is within a prescribed limit (i.e., within
the setting adjustment of the synchronizer);
or,
2.
The slip is essentially zero and the phase
angle difference is less than 3 degrees. In
this case, the phase angle between the two
systems must have passed through 180
degrees to enable the synchronizer.
When 1 or 2 are met, the automatic synchronizer will
operate in a bus-to-bus environment as it would in the
case of an oncoming generator: it will provide a
closure command at the appropriate advance angle so
that the breaker contacts close when the phase
difference is near zero.
DEFINING THE PARAMETERS
The relationship between slip, advance angle and
breaker closing time is shown in Figure 1 and de-
scribed by the formula:
A
A
= 360 * (T
CB
+ T
R
) * F
S
A
A
= advance angle in degrees. (This is the time,
measured in electrical degrees, between initiation of
breaker closure and the actual closure of the breaker
contacts.)
360 = degrees per slip cycle.
T
CB
= the closing time of the selected circuit breaker in
seconds. (This is the time required from the closure of
the synchronizer’s output contact to the actual closing
of the circuit breaker’s contacts. T
CB
is programmed in
the synchronizer memory for each circuit breaker to be
controlled by the synchronizer.)
T
R
= response time in seconds of the synchronizer’s
Breaker Close output relay. This is a factory preset
constant.
F
S
= slip frequency. This is the magnitude difference
in frequency between the oncoming generator and the
system bus.