Siemens 6MD85, Manual

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Parameter: T pause f
•
Default setting
(_:145) T pause f
=
10.00 s
With the parameter
T pause f
, you set the dead time between the balancing commands. This allows the
controller and the generator to respond to the control pulse. Determine the final setting value during commis-
sioning.
Parameter: Δf set point for balancing
•
Default setting
(_:146) Δf set point for balancing
=
0.04 Hz
With the parameter
Δf set point for balancing
, you define the set point value for the frequency
adjustment. The default setting is a practicable value.
EXAMPLE:
Measured differential frequency df = 0.5 Hz
Parameter setting value
df/dt of the controller
= 1 Hz/s
Set point value
Δf set point for balancing
= 0.04 Hz
Use the following equation to calculate the duration of the balancing pulse:
[fo_df-dt_1hz-s, 1, en_US]
Parameter: Smoothing
•
Default setting
(_:147) Smoothing
=
1
The parameter
Smoothing
is used for additional smoothing of the df frequency measured values. If the meas-
ured differential frequency df fluctuates during commissioning, increase the default setting. For hydropower
plants, in particular, the generator speed may fluctuate, necessitating corresponding adjustment.
Smoothing results in proportional transmission behavior with a delay of the 1st order (PT1 behavior).
Figure 6-89 allows you to estimate the effect of the setting value of the parameter.
Parameter: T close without balancing
•
Default setting
(_:148) T close without balancing
=
5.00 s
With the parameter
T close without balancing
, you set the time within which no balancing commands
are to be issued. This avoids having the frequency change at the moment of switching. The time is thus the
remaining duration up to a possible switching. The parameter
T close without balancing
is active if
the frequency difference is within the set band (see Figure 6-82 ).
Proceed as follows to estimate the time:
Use the set frequency difference to calculate the period duration. The phasors are in phase opposition after
half of that time. Do not adjust the frequency within the range from approximately 120° to a maximum of
180° before switching.
EXAMPLE:
The set frequency band in the example is df = 0.1 Hz.
At this threshold, the period duration is as follows:
[fo_Tdf, 1, en_US]
Assuming a constant differential frequency of 0.1 Hz, dα changes by 360° in 10 s.
Control Functions
6.4 Synchronization Function
SIPROTEC 5, High-Voltage Bay Controller, Manual 403
C53000-G5040-C015-9, Edition 11.2017