Power System - GE C70 Instruction Manual

CHAPTER 5: SETTINGS
Three bank of phase/auxiliary VTs can be set, where voltage banks are denoted in the following format (X represents the
module slot position letter):
Xa, where X = {F, M, U} and a = {5}
See the Introduction to AC Sources section at the beginning of this chapter for details.
With VTs installed, the relay can perform voltage measurements as well as power calculations. Enter the
made to the system as "Wye" or "Delta." An open-delta source VT connection is entered as "Delta."
CONNECTION
The nominal
PHASE VT F5 SECONDARY
voltage is applied to the VT primary.
For example, on a system with a 13.8 kV nominal primary voltage and with a 14400:120 volt VT in a delta
connection, the secondary voltage is 115; that is, (13800 / 14400) × 120. For a wye connection, the voltage value
entered must be the phase to neutral voltage, which is 115 /
On a 14.4 kV system with a delta connection and a VT primary to secondary turns ratio of 14400:120, the voltage
value entered is 120; that is, 14400 / 120.
If the
PHASE VT F5 CONNECTION

5.5.2 Power system

SETTINGS  SYSTEM SETUP  POWER SYSTEM
 POWER SYSTEM

The power system
NOMINAL FREQUENCY
cannot be measured from available signals. This can 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 setting matches the power system phase sequence and informs the relay of the actual system phase
PHASE ROTATION
sequence, either ABC or ACB. CT and VT inputs on the relay, labelled as A, B, and C, must be connected 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 configured for the signal source. Phase
voltages takes precedence, followed by auxiliary voltage, then phase currents, and finally ground current.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
PHASE VT F5

RATIO: 1.00 :1
AUXILIARY VT F5

CONNECTION: Vag
AUXILIARY VT F5

SECONDARY: 66.4 V
AUXILIARY VT F5

RATIO: 1.00 :1
voltage setting is the voltage across the relay input terminals when nominal
is set to "Delta", the relay does not calculate voltage harmonics.
NOMINAL FREQUENCY:

60 Hz
PHASE ROTATION:

ABC
FREQUENCY AND PHASE

REFERENCE: SRC 1
FREQUENCYTRACKING:

Enabled
value is used as a default to set the digital sampling rate if the system frequency
setting determines which signal source is used (and hence which AC signal) for
Range: 1.00 to 24000.00 in steps of 0.01
Range: Vn, Vag, Vbg, Vcg, Vab, Vbc, Vca
Range: 25.0 to 240.0 V in steps of 0.1
Range: 1.00 to 24000.00 in steps of 0.01
= 66.4.
Range: 25 to 60 Hz in steps of 1
Range: ABC, ACB
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: Disabled, Enabled
SYSTEM SETUP
PHASE VT F5
5
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