Underfrequency Protection Daptuf; Frequency Gradient Protection Dapfrc - ABB RELION 630 Series Applications Manual

Section 3
REG630 variants
3.2.6.11
3.2.6.12
38

Underfrequency protection DAPTUF

Underfrequency protection function is used for detecting deficit of generation
compared to load. Two instances of underfrequency functions are used with DT
characteristic. The set of three phase voltages, U3P, is connected to the inputs.
A common operate and start signal from the both underfrequency protection functions
is connected to an OR-gate to form a combined underfrequency operate and start
signal, which provides a LED indication on the LHMI. Also a separate start signal
from both instances is connected to the disturbance recorder. However, the operate
signal from both stages is connected to OR-gate to form a combined underfrequency
operate signal, and connected to the disturbance recorder.
The function is blocked when the generator circuit breaker is in open position.

Frequency gradient protection DAPFRC

Frequency gradient protection function is used for detecting the increase or decrease
of the fast power system frequency at an early stage. Two instances of frequency
gradient protection functions are used with DT characteristics. The set of three phase
voltages, U3P, is connected to the inputs. The frequency gradient function is blocked
when the generator circuit breaker is in open position.
A common operate and start signal from the both frequency gradient protection
functions is connected to an OR-gate to form a combined frequency gradient operate
and start signal, which provides a LED indication on the LHMI. Also a separate start
signal from the both instances is connected to the disturbance recorder. However, the
operate signal from both stages is connected to the OR-gate to form a combined
frequency gradient operate signal, and connected to the disturbance recorder.
The function is blocked when the generator circuit breaker is in open position.
1MRS757582 C
REG630
Application Manual