Power System - GE B90 Instruction Manual

5 SETTINGS

PATH: SETTINGS SYSTEM SETUP
 POWER SYSTEM

MESSAGE
MESSAGE
The power system
NOMINAL FREQUENCY
cannot be measured from available signals. This may happen if the signals are not present or are heavily distorted. Before
reverting to the nominal frequency, the frequency tracking algorithm holds the last valid frequency measurement for a safe
period of time while waiting for the signals to reappear or for the distortions to decay.
The
FREQUENCY AND PHASE REFERENCE
The phase reference and frequency tracking AC signals are selected based upon the configuration, regardless of whether
or not a particular signal is actually applied to the relay.
Phase angle of the reference signal will always display zero degrees and all other phase angles will be relative to this sig-
nal. If the pre-selected reference signal is not measurable at a given time, the phase angles are not referenced.
The phase angle referencing is done via a phase locked loop, which can synchronize independent UR-series relays if they
have the same AC signal reference. These results in very precise correlation of time tagging in the event recorder between
different UR-series relays provided the relays have an IRIG-B connection.
FREQUENCY TRACKING
cial variable-frequency applications.
NOTE
GE Multilin


POWER SYSTEM

NOMINAL FREQUENCY:
60 Hz
FREQUENCY AND PHASE
REFERENCE: F1
FREQUENCY TRACKING:
Enabled
value is used as a default to set the digital sampling rate if the system frequency
setting determines which AC signal is used for phase angle reference.
should only be set to "Disabled" in very unusual circumstances; consult the factory for spe-
B90 Low Impedance Bus Differential System
5.3 SYSTEM SETUP
5.3.2 POWER SYSTEM
Range: 25 to 60 Hz in steps of 1
Range: available CT and VT channels
Range: Disabled, Enabled
5
5-57