Relay Commissioning
7-25
SEL-300G Instruction Manual
Date Code 20060731
Step 3.
Apply the test voltages calculated in Step 1. Next, apply the test currents and record
the element operating time, Ttest. Remove the test voltages and currents.
Ttest = _________ seconds
Step 4.
Calculate the relay timing error using the equation:
100
•
D
1
Z
D
1
Z
Ttest
error
%
⎟
⎠
⎞
⎜
⎝
⎛
−
=
% error = _________
Repeat the test for Zone 2, if desired.
Volts/Hertz (24) Element
Equipment Needed
•
SEL-300G Relay under test.
•
Two- or Three-Phase AC Voltage Test Source with adjustable magnitude and phase
angle.
•
PC with terminal emulation software and appropriate serial cable to connect the
PC-COM port to the relay.
Test Source Connections
When DELTA_Y = Y, connect the voltage sources according to Figure 7.9. When
DELTA_Y = D, connect the voltage sources according to Figure 7.10. Current sources are not
needed for this test.
Basic Element Operation
The
SEL-300G
volts/hertz element is designed to detect generator overexcitation that occurs when
the generator terminal voltage is increased or operating frequency is decreased. The relay
measures the generator phase-to-phase voltages and the generator frequency, then calculates the
volts/hertz using the following equation:
100
•
VNOM
FNOM
•
Freq
Vpp
V/Hz
%
=
where:
Vpp
= measured generator phase-to-phase voltage, largest of the VAB, VBC,
and VCA
Freq
= measured generator frequency
FNOM
= nominal generator frequency (Relay Global Setting)
VNOM
= nominal generator phase-to-phase voltage
When the measured phase-to-phase voltage and generator frequency are equal to the nominal
settings FNOM and VNOM, the result of the equation above is 100 percent. If the phase-to-phase
voltage increases or the operating frequency decreases, the equation result exceeds 100 percent
and, depending on settings, the relay overexcitation elements can pick up.
Summary of Contents for SEL-300G
Page 1: ...SEL 300G Multifunction Generator Relay Instruction Manual 20060731 PM300G 01 NB ...
Page 4: ......
Page 6: ......
Page 138: ......
Page 166: ......
Page 170: ......
Page 288: ......
Page 290: ......
Page 328: ......
Page 442: ......
Page 456: ......
Page 458: ......
Page 468: ......
Page 470: ......
Page 512: ......
Page 516: ......
Page 518: ......
Page 552: ......
Page 554: ......
Page 560: ......
Page 578: ......
Page 626: ......
Page 724: ......
Page 728: ......