ABB REG670 - Setting Guidelines

R
X
Z1, Fast zone
Z2, Slow zone
IEC06000453_3_en.vsd
Underexcitation Protection
Restraint area
IEC06000453 V3 EN
Figure 150: LEXPDIS in the IED, realized by two impedance circles and a
directional restraint possibility
8.6.3 Setting guidelines
Here is described the setting when there are two zones activated of the protection.
Zone Z1 will give a fast trip in case of reaching the dynamic limitation of the stability.
Zone 2 will give a trip after a longer delay if the generator reaches the static limitation
of stability. There is also a directional criterion used to prevent trip at close in external
faults in case of zones reaching into the impedance area as shown in figure
150.
Operation: With the setting Operation LEXPDIS function can be set On/Off.
IBase, (refer to GlobalBaseSel): The setting IBase is set to the generator rated Current
in A, see equation
170.
3
N
N
S
IBase
U
=
×
EQUATION1707 V1 EN (Equation 170)
UBase: The setting UBase is set to the generator rated Voltage (phase-phase) in kV.
1MRK 502 071-UEN - Section 8
Impedance protection
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 287
Application manual