Protective Elements
LB – Load Blinder (Load Encroachment)
Available elements:
LB
An expanded operating characteristic of a distance protection function can reduce line/generator loadability. If we
want to provide sufficient arc resistance coverage and at the same time avoid the possibility for tripping under
maximum load conditions, we can use the Load Blinder (load encroachment) function to restrict the operating
characteristic of distance protection.
The operating characteristic of the Load Blinder module is a segment of the complex impedance plane, with the
exception of a circle around the origin. It is therefore defined by three settings: the two segment angles
»Imp. Angle
1«
,
»Imp. Angle 2«
, and the circle radius
»Imp. Circ. Rd«
:
Load Blinder Characteristic (area in bright-blue color)
In other words, the load encroachment area spreads on the outside of the impedance circle, being limited by the two
blinders which are defined by the impedance angles, see the light-blue area in the diagram.
If the measured impedance is within the load encroachment area the function will initiate »Pickup« and after the
configured time delay (»t-Delay«) the signal »Operate«.
844 MCDGV4 DOK-HB-MCDGV4-2E
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