ABB REG670 Applications Manual page 192

Section 8
Impedance protection
186
2
x U 10 13
= × =
X t r
T
100 S 100 65
IEC-EQUATION2318 V1 EN
Then the reach in primary ohms shall be set to 100% of transformer impedance. Thus
the reach shall be set to 0,26Ω primary.
Set the first zone of Full-scheme distance measuring, Mho characteristic ZMHPDIS
to disable phase-to-earth loops and enable phase-to-phase loops:
• The parameter GlobalBaseSel shall be set in order to select the global base value
group GBASVAL where the base voltage UBase and the base current IBase are
defined; UBase is the generator rated phase-phase voltage (UBase=13,2kV) and
IBase is the generator rated phase current (IBase=3062A).
• Parameter DirMode shall be set to Offset.
• Parameter OffsetMhoDir shall be set to Non-directional.
• The phase-to-earth measuring loops shall be disabled by setting OpModePE=Off.
• The phase-to-phase measuring loops shall be enabled and corresponding settings
in primary ohms for forward and reserve reach and time delay shall be entered
accordingly:
• Parameter ZPP shall be set to 0,260Ω.
• Parameter ZrevPP shall be set to 0,260Ω.
• Parameter tPP shall be set to 1,0000s.
• Parameter ZAngPP shall be set to default value 85 Deg.
Set the following for the directional element ZDMRDIR:
• The parameter GlobalBaseSel shall be set in order to select the global base value
group GBASVAL where the base voltage UBase and the base current IBase are
defined; UBase is the generator rated phase-phase voltage (UBase=13,2kV) and
IBase is the generator rated phase current (IBase=3062A).
• Parameter DirEvalType shall be set to Imp/Comp.
• Other settings can be left on the default values.
By doing this offset mho characteristic for zone one will be achieved as shown in
figure 79. Note that for this particular example ZPP=ZRevPP=0,26Ω. Thus the
operating characteristic for this particular application will be a circle with a centre in
the impedance plane origo.
By following the same procedure other mho zones can be set.
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
2
× = W
0, 26
1MRK 502 071-UEN -
Application manual