Syn 5201/Syn - ABB SYN 5201 Operating Instructions Manual

Operating Instructions
Multiple commands MULTIPLE CMD
With this setting one can select whether the synchronizer should only give one
command or should always give a command if all conditions are fulfilled. In
synchrocheck operation, i.e. with command generation switched off (tp on = OFF or 0),
MULTIPLE CMD has no influence. The contacts close with each release.
4.2.3 Parameter group Paralleling Conditions
Slip limit oversynchronous –smax and sub-synchronous +smax
The setting value is based on different criteria, depending on the application:
a) normal synchronization
b) coarse synchronization
c) paralleling of synchronous lines
d) paralleling of asynchronous lines
a) Normal synchronization
The slip limit values set in practice are far from placing a serious load on the machine,
even in large machines. Usual setting values: 0.1 to 0.5 %; default setting: 0.4 %
The following are a number of points which can influence the setting value:

Smaller slip limits should be chosen for large and modern generators.

Gas turbines are more sensitive (smaller tolerance band) than hydrogenerators.

Lower values should be selected if fine synchronization has priority and higher
values if fast synchronization is to take place.

Lower slip values are usually selected where settings are made for synchrocheck
operation to monitor manual synchronizing.

If one wishes to prevent the tripping of the reverse power relay, the sub-synchronous
limit +smax is reduced or set to zero.
b) Coarse synchronization
With coarse synchronization, i.e. synchronization without frequency adjusting
commands (e.g. during run-down), in order to carry out paralleling with 100 % reliability
the slip limits must be set in such a way that at least one phase zero passage occurs
within the permissible range:
Key:
fn = nominal frequency [Hz]
ds/dt = acceleration [%/s] (known or read actual value from SYNCHROTACT 5).
If the determined value appears inadmissibly high, a lower value can be set. However, in
this case it is not guaranteed that paralleling can be achieved with only one attempt at
synchronization.
c) Paralleling of synchronous lines
If only synchronous sources are paralleled, the slip limits do not need to be set
abb
ABB Switzerland Ltd
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Document No Art Part
3BHS109762 E01

SYN 5201/SYN 5202

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