V/Hz limiter
The volts-per-hertz limiter (VHZL) is used to avoid high saturation in magnetic cores when the
synchronous generator's speed is low due to a loss of torque from the turbine. Mainly this can happen
with the island mode of operation. The limiter operates by limiting the maximum value (V
adj,max
) of the
AVR reference value (V
ref
).
The diagram below depicts the transfer function of the volts-per-hertz limiter.
Figure. 6.2.1.4.4 - 223. V/Hz limiter transfer function.
The knee point in Hz is calculated as V
T
* F
NOM
/ VHz
LIM
with V
T
being the actual stator voltage in p.u.
Table. 6.2.1.4.4 - 365. V/Hz limiter setting parameters.
Name
Range
Step
Default
Comments
V/Hz limiter (VHZ) status
0: Enabled
1: Limiter active
-
-
Displays the status of the volts-per-
hertz limiter.
V/Hz output now
-500.00…500.00p.u./p.u. 0.01p.u./p.u. 0.00p.u./p.u. Defines the output of the volts-per-
hertz limitor at the moment.
V/Hz limiter
0: Disabled
1: Enabled
-
1: Enabled
Enables and disables the volts-per-
hertz limiter.
V/Hz limit (generator
voltage/generator
frequency)
0.00...10.00 1/s
0.01 1/s
1.10 1/s
This parameter defines the limit at
which the limiter is activated.
6.2.1.5 Power system stabilizer
The power system stabilizer (PSS) is a function required by grid companies for certain geographical
areas and machines of certain sizes. The purpose of the PSS is to dynamically adjust excitation so that
the machine damps any network power fluctuations. Additionally, the PSS reduces torque fluctuations
between the generator and the prime mover. The transfer function of the stabilizer follows the IEEE
recommendation (PSS2A, PSS2B, PSS2C).
Table. 6.2.1.5 - 366. PSS setting parameters.
Name
Range
Step
Default
Power system stabilizer (PSS2B)
0: Disabled
1: Enabled
-
0: Disabled
PSS block release time (after ext. block released)
6.000…180.000s
0.005s
6.000s
PSS output signal to AVR control
-5000.000…5000.000p.u.
0.001p.u.
0.000p.u.
KS1 PSS gain
0.00...25.00
0.01
0.00
Genera
Generattor Commander
or Commander
Instruction manual
Version: 2.07
444
© Arcteq Relays Ltd
IM00001
Содержание Generator Commander
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