GE 750 Instruction Manual page 344

METERING
7.3.1 Current
Metering
7 - 16
7.3 Metering
Phase Current Inputs
For these tests, refer to the figures on page –4 for test connections. The expected accuracy
is as follows:
For 1 A CTs: ±0.01 A for 0.01 to 1.99 A; ±0.2 A for 2.00 to 20.00 A
For 5 A CTs: ±0.05 A for 0.05 to 9.99 A; ±1.0 A for 10.00 to 100.00 A
Use the following procedure to test Phase and Neutral Current Inputs:
The relevant actual values displays are located under subheading
and are:

A2 METERING CURRENT
(Magnitude)
A: B: C:
AVERAGE CURRENT:
PHASE A CURRENT:
PHASE B CURRENT:
PHASE C CURRENT:
NEUTRAL CURRENT:
POS SEQ CURRENT:
NEG SEQ CURRENT:
ZERO SEQ CURRENT:
 Inject 1-phase current of various values into the relay phase current
input one phase at a time, and observe the magnitude.
Note that the average, positive-sequence, negative-sequence and zero-
sequence magnitudes are 1/3 of the phase current magnitude for this
test.
The neutral current will match the phase current magnitude.
 Inject 3-phase current of various values and angles into the relay phase
current input and note the measured current phasors and symmetrical
components.
Use the following procedure for Ground and Sensitive Ground Current Inputs:
The relevant actual values displays are located under subheading
as follows:

A2 METERING CURRENT
GND CURRENT:
SENSTV GND CURRENT:
 Inject current of various values into the relay ground input, Terminals
G10–H10, and note the current.
 Inject current of various values into the relay sensitive ground input,
Terminals G3–H3, and note the current.
Percent of Load-to-Trip
For these tests, refer to the figures on page –4 for test connections. The expected accuracy
is as follows:
Expected Accuracy: equivalent to that of phase current inputs
The relevant actual values displays are shown below:
(Magnitude)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
(Phasor)
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 7: COMMISSIONING