9146600990 Rev M
BE1-25A Appendix
A-1
Φ =
×
×
360
F
T
APPENDIX A
$
GLOSSARY
This appendix provides definitions for selected nomenclature used in this manual.
Advance Angle.
The angle in degrees prior to phase coincidence that the generator voltage waveform will
change relative to the bus voltage waveform during the period of time between initiation of breaker closing
and the actual closing of the circuit beaker contacts. This can be expressed by the equation:
Where:
Φ
is the advance angle in degrees
F is the slip frequency in hertz
T is the breaker closing time in seconds
Automatic Synchronizing System.
A relaying scheme that uses a synchronizing relay with one or more
elements that: 1) take into account the closing time of the controlled breaker to calculate when the advance
angle is proper to initiate closing, 2) cause the output contacts to open when a zero phase difference
between the sensed voltages occurs, and 3) monitor and control the frequency and voltage of the generator.
Bump Pulse.
If the oncoming generator and the bus are frequency matched but not phase matched (and
if the Auto-Synchronizer is equipped with a Frequency Matching option), these pulses (or, more precisely,
contact closures) are used to alter generator speed and, in turn, to induce a slip frequency that is within the
capture limits of the synchronizer.
Corrective Pulse.
A contact closure initiated by the Frequency Matching Option F1 to change generator
speed. A situation calls for Corrective Pulses when the slip frequency is greater than the allowable limit but
within the capture range.
F
S
.
Slip frequency: the difference between the system frequency and the generator frequency.
GF>BF. 1
An internal signal that inhibits the breaker closure signal unless the generator frequency is greater
than the bus frequency.
2
The designation of an external signal (or the terminals thereof) which causes the
Auto-Synchronizer to not issue a breaker closure signal unless the generator frequency is greater than the
bus frequency.
GV>BV. 1
An internal signal that inhibits the breaker closure signal unless the generator voltage is greater
than the bus voltage.
2
The designation of an external signal (or the terminals thereof) which causes the
Auto-Synchronizer to not issue a breaker closure signal unless the generator voltage is greater than the bus
voltage.
LO, HI.
Two internal signals developed by the MCU Sync module in response to the speed of an oncoming
generator relative to the bus frequency. These signals are used by the various options to determine the
direction of any correction or bump pulses issued by the Auto-Synchronizer.
Raise, Lower. 1
Refers to external signals delivered to the generator's control system to adjust frequency
or voltage (as the case may be) in the desired direction (up or down).
2
The names of two internal signals
developed by the Voltage Acceptance module to indicate to other modules the desired direction of any
corrective pulses to be issued.
SYNC.
An alternate name for the breaker closure signal.
)
V.
The difference voltage between the bus and the generator.
180
E
Out of Phase.
An internal pulse that is generated when the voltage of the bus and the voltage of the
generator vectorial pass each other (as components of the slip frequency). Each pulse thus generated
occurs at the midpoint of the slip frequency period. These pulses are used to strobe the Correction and
Bump pulses.
www
. ElectricalPartManuals
. com
