GE T35 User Manual

6-20 T35 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
METERING CHAPTER 6: ACTUAL VALUES
6
This menu displays metered values for real, reactive, and apparent power, as well as power factor. The "SRC 1" text is
replaced by the name programmed by the user for the associated source (see SETTINGS  SYSTEM SETUP  SIGNAL
SOURCES
).
When VTs are configured in wye, the T35 calculates power in each phase and three-phase power is measured as
S = V
A
x Î
A
+ V
B
x Î
B
+ V
C
x Î
C
Eq. 6-1
When VTs are configured in delta, the T35 does not calculate power in each phase and three-phase power is measured as
S = V
AB
x Î
A
+ V
CB
x Î
C
Eq. 6-2
where
S is the apparent power
V
A
, V
B
, V
C
, I
A
, I
B
, I
C
are phase voltage and phase current phasors
V
AB
and V
CB
are phase-to-phase voltage phasors
Î is the conjugate of I
6.4.3.7 Frequency metering
ACTUAL VALUES  METERING  SOURCE SRC 1  FREQUENCY
The metered frequency values are displayed in this menu. The "SRC 1" text is replaced by the name programmed by the
user for the associated source (see
SETTINGS  SYSTEM SETUP  SIGNAL SOURCES).
SOURCE FREQUENCY is measured via software-implemented zero-crossing detection of an AC signal. The signal is either a
Clarke transformation of three-phase voltages or currents, auxiliary voltage, or ground current as per source configuration
(see the
SYSTEM SETUP  POWER SYSTEM settings). The signal used for frequency estimation is low-pass filtered. The final
frequency measurement is passed through a validation filter that eliminates false readings due to signal distortions and
transients.
6.4.4 Tracking frequency
ACTUAL VALUES  METERING  TRACKING FREQUENCY
The tracking frequency displays here. The frequency is tracked based on the selection of the reference source with the
FREQUENCY AND PHASE REFERENCE setting in the SETTINGS  SYSTEM SETUP  POWER SYSTEM menu. See the Power
System section of chapter 5 for details.
6.4.5 FlexElements
ACTUAL VALUES  METERING  FLEXELEMENTS  FLEXELEMENT 1(16)
The operating signals for the FlexElements are displayed in pu values using the following definitions of the base units.

SRC 1 POWER FACTOR
φb: 1.000

SRC 1 POWER FACTOR
φc: 1.000
 FREQUENCY
 SRC 1

SRC 1 FREQUENCY:
0.00 Hz
 TRACKING FREQUENCY


TRACKING FREQUENCY:
60.00 Hz
 FLEXELEMENT 1


FLEXELEMENT 1
OpSig: 0.000

GE T35 Specifications

General

Brand	GE
Model	T35
Category	Relays
Language	English