Signal Sources - GE t60 Instruction Manual

5 SETTINGS
The phase sequence of the power system is required to properly calculate sequence components and power parameters.
The setting matches the power system phase sequence. Note that this setting informs the relay of the
PHASE ROTATION
actual system phase sequence, either ABC or ACB. CT and VT inputs on the relay, labeled as A, B, and C, must be con-
nected to system phases A, B, and C for correct operation.
The
FREQUENCY AND PHASE REFERENCE
phase angle reference. The AC signal used is prioritized based on the AC inputs that are configured for the signal source:
phase voltages takes precedence, followed by auxiliary voltage, then phase currents, and finally ground current.
For three phase selection, phase A is used for angle referencing (
phase signals is used for frequency metering and tracking (
ing fault, open pole, and VT and CT fail conditions.
The phase reference and frequency tracking AC signals are selected based upon the Source 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 relays provided the relays have an IRIG-B connection.
FREQUENCY TRACKING
cial variable-frequency applications.
NOTE
Systems with a phase sequence of ACB require special consideration described in the Phase Relation-
ships of Three-phase Transformers section.
NOTE
PATH: SETTINGS SYSTEM SETUP
SOURCE 1
MESSAGE
MESSAGE
MESSAGE
MESSAGE
Four identical Source menus are available. The "SRC 1" text can be replaced by with a user-defined name appropriate for
the associated source.
"F" and "M" represent the module slot position. The number directly following these letters represents either the first bank of
four channels (1, 2, 3, 4) called "1" or the second bank of four channels (5, 6, 7, 8) called "5" in a particular CT/VT module.
Refer to the Introduction to AC Sources section at the beginning of this chapter for additional details on this concept.
It is possible to select the sum of up to five (5) CTs. The first channel displayed is the CT to which all others will be referred.
For example, the selection "F1+F5" indicates the sum of each phase from channels "F1" and "F5", scaled to whichever CT
has the higher ratio. Selecting "None" hides the associated actual values.
The approach used to configure the AC Sources consists of several steps; first step is to specify the information about each
CT and VT input. For CT inputs, this is the nominal primary and secondary current. For VTs, this is the connection type,
ratio and nominal secondary voltage. Once the inputs have been specified, the configuration for each Source is entered,
including specifying which CTs will be summed together.
GE Multilin
setting determines which signal source is used (and hence which AC signal) for
V
should only be set to "Disabled" in very unusual circumstances; consult the factory for spe-

SIGNAL SOURCES

SOURCE 1(4)
SOURCE 1 NAME:
SRC 1
SOURCE 1 PHASE CT:
None
SOURCE 1 GROUND CT:
None
SOURCE 1 PHASE VT:
None
SOURCE 1 AUX VT:
None
T60 Transformer Management Relay
V = V ), while Clarke transformation of the
ANGLE REF A
(
= 2V – V – V
FREQUENCY A B C
Range: up to 6 alphanumeric characters
Range: None, F1, F5, F1+F5,... up to a combination of
any 5 CTs. Only Phase CT inputs are displayed.
Range: None, F1, F5, F1+F5,... up to a combination of
any 5 CTs. Only Ground CT inputs are displayed.
Range: None, F1, F5, M1, M5
Only phase voltage inputs will be displayed.
Range: None, F1, F5, M1, M5
Only auxiliary voltage inputs will be displayed.
5.3 SYSTEM SETUP
) 3 ⁄
) for better performance dur-
5.3.3 SIGNAL SOURCES
5-39
5