Standstill Protection; General - ABB REG316 4 Series Operating Instructions Manual

REG 316*4 1MRB520049-Uen / Rev. B
I
R
Fig. 4.3
4.2.2.

Standstill protection

4.2.2.1.

General

The purpose of the standstill protection is to isolate the generator
from the system as quickly as possible, if it is connected to the
system by mistake, e.g. when stationary, during start-up or when
running without voltage.
The protection must have a short operating time to minimise the
mechanical stress on the rotors and bearings of generator and
turbine, should the unit be connected to the system suddenly
under these conditions. Nevertheless, it must remain stable dur-
ing external faults and transients.
Standstill protection can be provided by a fast overcurrent or
power function. Function modules for both alternatives are in-
cluded in the REG 316*4 function library. The following example
shows the overcurrent alternative.
Saturated c.t.
E
2
R
S
I >
I
2
VDR
Restricted E/F protection of a Y connected trans-
former winding
ABB Switzerland Ltd
Internal E/F
I
E
DU
i
I
2
R
S
Shorting contact
I >
External
E/F
HEST 935 007 FL
4-11