Schweitzer Engineering Laboratories SEL-700G Series, Инструкция по эксплуатации

Страница: 259 / 824

4.153
Date Code 20170814 Instruction Manual SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
Synchronism Elements
Synchronism-Check Elements (Generator Breaker, X-Side)
A synchronism-check relay verifies that the generator frequency, voltage
magnitude, and phase angle match the system frequency, voltage magnitude,
and phase angle before allowing the generator breaker to be closed. The
SEL-700G offers a built-in synchronism-check function that you can operate
manually or automatically with the autosynchronizer function described later.
The relay uses the VS voltage input to measure system voltage. You should
connect this input to the secondary of a phase-to-ground or phase-to-phase
connected VT on the system or bus side of the generator circuit breaker. See
Section 2: Installation for connection examples.
The relay uses the X-side positive-sequence voltage to measure the generator
frequency. Other generator voltage conditions use the voltage selected by the
SYNCP setting, set to match the VS input connection. If the slip frequency
(frequency difference between the generator and system) is within settable
bounds, both voltage magnitudes are within settable bounds, and the phase-
angle difference is within limits, the relay synchronism-check function
permits the SEL-700G to issue a CLOSE signal or close an output contact to
supervise an external close condition. The relay takes into account the breaker
closing time and the present slip frequency to issue a close signal timed to
have the system and generator at a settable angle difference when the breaker
closes.
If a generator step-up transformer is connected between the generator
terminals and the open generator breaker, the SEL-700G can account for the
phase shift the transformer connections introduce without using auxiliary
voltage transformers.
In the event that the generator breaker is slow to close, the generator and
system voltages might drift to a phase angle that is unsafe for closing before
the breaker closes. In this event, the relay detects that the phase angle between
the generator and system voltages exceeds a safe closing angle and can issue a
breaker close failure signal to perform breaker failure tripping and protect the
generator.
446 230.00 186.82 340.14 268.90 17.95
464 240.00 190.45 353.14 278.90 18.34
482 250.00 194.08 366.53 289.10 18.73
Table 4.46 RTD Resistance Versus Temperature (Sheet 2 of 2)
Temp
(°F)
Temp
(°C)
100
Platinum
120
Nickel
100
Nickel
10
Copper
Table 4.47 X-Side Synchronism-Check Settings (Sheet 1 of 2)
Setting Prompt Setting Range Setting Name := Factory Default
SYNC CHECK EN Y, N E25X := N
V-WINDOW LOW 0.00–300.00 V 25VLOX := 58.3
V-WINDOW HIGH 0.00–300.00 V 25VHIX := 69.7
MAX VOLTAGE DIFF OFF, 1.0–15.0 % 25VDIFX := 3.3
VOLT RATIO CORR 0.500–2.000 25RCFX := 1.000
GEN-VOLTAGE HI Y, N GENV+ := Y
MIN SLIP FREQ –1.00 to 0.99 Hz 25SLO := 0.05
NOTE:
If EXT3V0_X is set to VS to
connect an external zero-sequence
voltage to the
VS-NS input on the relay,
synchronism-check and
autosynchronizing functions are
disabled.