ABB RELION REX640, Техническое руководство, Страница: 1574 / 1960

- If the voltage difference reaches the target value with a hysteresis band that
is in the middle of the tolerance band specified by the settings
Voltage Diff Ov
Ex and Voltage Diff Un Ex, the raise and lower commands are reset.
• During matching of network CB synchronization
- If either of the AVR limit alarms
AVR_ALM_LO
and
AVR_ALM_HI
is TRUE, it
resets the voltage raise and lower commands.
- When the generator is selected for fine tuning, if the voltage difference is
within the limits of tolerance band specified by the settings
Voltage Diff Ov Ex
and
Voltage Diff Un Ex, the raise and lower commands are reset.
- When the generator is selected for coarse tuning, if the voltage difference
reaches within the limits of Coarse Volt Diff Ov and Coarse Volt Diff Un, the
raise and lower commands are reset.
Voltage rate of change tuning
When the control command parameter
Tune V and F match is set to "Volt match
rate", the function calculates the generator voltage matching rate (dU/dt). The
calculated voltage matching rate is stored to the nonvolatile memory output
VOLT_CHG_RTE
and is available in the Monitored data view. Once stored, the value
from the output
VOLT_CHG_RTE
can be used to set the setting Volt rate of change.
This tuned voltage matching rate proceeds as follows:
1. The generator voltage is adjusted until it lies in the range of 95...97 % of the line
voltage, then the adjusting pulse is discontinued.
2. Ten seconds after the first adjusting pulse, the voltage difference ΔU0 is
measured, then a voltage raise command
RAISE_U
lasting 5 s is given. Ten
seconds after the end of the pulse, the voltage difference ΔU is measured and
dU/ dt calculated according to the following formula:
dU
dt
U U
=
− ∆ ∆
0
5
(Equation 362)
3. With this dU/dt value, the generator voltage is brought back to approximately
96 %.
Ten seconds later, the generator voltage is brought to approximately 100 % with
the same dU/dt value. After ten seconds, dU/dt is calculated again and shown as
monitored data output
VOLT_CHG_RTE
.
Frequency matching
Working range of the frequency matcher
No adjustment takes place between 1/3 and 2/3 of smax. The adjusting pulse is
discontinued as soon as the slip passes through zero. The command length does
not fall below a settable
Freq pulse Min Dur. After an adjusting command, the
system waits for the set
Freq pulse off Intv so that the actual values can stabilize to
the new set point.
Control functions 1MRS759142 F
1574 REX640
Technical Manual