Signal Sources - GE G30 Instruction Manual

CHAPTER 5: SETTINGS
The setting allows the user to dynamically change the phase rotation used for phasor calculations.
REVERSE PH ROTATION
This allows the G30 to follow the current phase rotation of the protected generator. For example, if the
setting is "ABC" but the condition defined for opposite phase rotation is true, then the phase rotation used for phasor
calculation switches to "ACB." This feature is only intended for use in special applications, such as pumped storage
schemes
The
FREQUENCY AND PHASE REFERENCE
phase angle reference. The AC signal used is prioritized based on the AC inputs 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 (V
signals is used for frequency metering and tracking (V
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 always displays zero degrees and all other phase angles are relative to this signal. 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. This results in very precise correlation of phase angle indications between different UR-
series relays.
is set to "Disabled" only in unusual circumstances; consult GE Grid Solutions for special variable-
FREQUENCY TRACKING
frequency applications.
The frequency tracking feature functions only when the G30 is in the "Programmed" mode. If the G30 is "Not
Programmed," then metering values are available but can exhibit significant errors.
Systems with an ACB phase sequence require special consideration. See the Phase Relationships of Three-phase
Transformers section of chapter 5.

5.5.3 Signal sources

SETTINGS  SYSTEM SETUP  SIGNAL SOURCES  SOURCE 1(4)
 SOURCE 1

Identical menus are available for each source. The "SRC 1" text can be replaced by with a user-defined name appropriate
for the associated source.
The first letter in the source identifier represents the module slot position. The number directly following this letter
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. See the Introduction to AC Sources section at the beginning of this chapter for details.
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
setting determines which signal source is used (and hence which AC signal) for
FREQUENCY
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
= V ), while Clarke transformation of the phase
ANGLE REF A
= (2V - V - V ) / 3) for better performance during fault,
A B C
Range: up to 20 alphanumeric characters
Range: None, F1,... up to any 6 CTs. Only Phase CT
inputs are displayed.
Range: None, F1,... up to any 6 CTs. Only Ground CT
inputs are displayed.
Range: None, F5, M5
Only phase voltage inputs are displayed
Range: None, F5, M5
Only auxiliary voltage inputs are displayed
SYSTEM SETUP
PHASE ROTATION
5
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