5-104
T60 Transformer Protection System
GE Multilin
5.4 SYSTEM SETUP
5 SETTINGS
5
5.4.2 POWER SYSTEM
PATH: SETTINGS
SYSTEM SETUP
POWER SYSTEM
The power system
NOMINAL FREQUENCY
value is used as a default to set the digital sampling rate if the system 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 phase sequence of the power system is required to properly calculate sequence components and power parameters.
The
PHASE ROTATION
setting matches the power system phase sequence. Note that this setting informs the relay of the
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
setting determines which signal source is used (and hence which AC signal) for
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 (
), while Clarke transformation of the
phase signals is used for frequency metering and tracking (
) for better performance dur-
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 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.
FREQUENCY TRACKING
is set to
“
Disabled
”
only in unusual circumstances; consult the factory for special variable-
frequency applications.
The frequency tracking feature functions only when the T60 is in the “Programmed” mode. If the T60 is “Not Pro-
grammed”, then metering values are available but can exhibit significant errors.
Systems with an ACB phase sequence require special consideration. Refer to the Phase relationships of three-
phase transformers sub-section of chapter 5.
POWER SYSTEM
NOMINAL FREQUENCY:
60 Hz
Range: 25 to 60 Hz in steps of 1
MESSAGE
PHASE ROTATION:
ABC
Range: ABC, ACB
MESSAGE
FREQUENCY AND PHASE
REFERENCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
MESSAGE
FREQUENCY TRACKING:
Enabled
Range: Disabled, Enabled
V
ANGLE REF
V
A
=
V
FREQUENCY
2
V
A
V
B
–
V
C
–
(
)
3
⁄
=
NOTE
NOTE
NOTE
Summary of Contents for T60
Page 6: ...vi T60 Transformer Protection System GE Multilin TABLE OF CONTENTS ...
Page 14: ...xiv T60 Transformer Protection System GE Multilin TABLE OF CONTENTS ...
Page 34: ...1 20 T60 Transformer Protection System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 490: ...5 344 T60 Transformer Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 522: ...6 32 T60 Transformer Protection System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Page 536: ...7 14 T60 Transformer Protection System GE Multilin 7 1 COMMANDS 7 COMMANDS AND TARGETS 7 ...
Page 568: ...10 12 T60 Transformer Protection System GE Multilin 10 6 DISPOSAL 10 MAINTENANCE 10 ...
Page 596: ...A 28 T60 Transformer Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 716: ...B 120 T60 Transformer Protection System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 762: ...E 10 T60 Transformer Protection System GE Multilin E 1 IEC 60870 5 104 PROTOCOL APPENDIX E E ...
Page 774: ...F 12 T60 Transformer Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...