ABB Relion REG670, Technical Manual

Page: 261 / 1298

7.5.6 Monitored data
Table 104: PSPPPAM Monitored data
Name Type Values (Range) Unit Description
SFREQ REAL - Hz Slip frequency
SLIPZOHM REAL - Ohm Slip impedance in ohms
SLIPZPER REAL - % Slip impedance in
percent of ZBase
UCOS REAL - kV UCosPhi voltage
UCOSPER REAL - % UCosPhi voltage in
percent of UBase
7.5.7 Operation principle
If the generator is faster than the power system, the rotor movement in the impedance
and voltage diagram is from right to left and generating is signaled. If the generator is
slower than the power system, the rotor movement is from left to right and motoring
is signaled (the power system drives the generator as if it were a motor).
The movements in the impedance plane can be seen in Figure 107 . The transient
behavior is described by the transient EMF's E
A
and E
B
, and by X'
d
, X
T
and the
transient system impedance Z
S
.
1MRK502052-UEN B
Section 7
Impedance protection
255
Technical manual