Section 4 1MAC309294-MB F
Protection functions
224 RER620
Technical Manual
This time delay can be set and it is used to prevent unwanted load-shedding actions when
the system frequency recovers to the normal level.
Once the frequency has stabilized, 81S can restore the load that is shed during the
frequency disturbance. The restoration is possible manually or automatically.
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.
4.4.2.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are “On” and “Off”.
The operation of the load shedding and restoration function can be described using a
module diagram. All the modules are explained in the next sections.
Throughout this document, “high df/dt” is used to mean “a high rate of
change of the frequency in negative direction.”
To Next Page
Loading...
Need help?
General
