ABB RER620 Technical Manual page 166

Section 4
Protection functions
160
• The Max forward angle and Max reverse angle settings are not settable, but have a
fixed value of 88 degrees
• The sector limits of the fixed sectors are rounded.
Sector rounding in the phase angle classic 88 consists of three parts:
• If the current amplitude is between 1...20 percent of the nominal current, the sector
limit increases linearly from 73 degrees to 85 degrees
• If the current amplitude is between 1...100 percent of the nominal current, the sector
limit increases linearly from 85 degrees to 88 degrees
• If the current amplitude is more than 100 percent of the nominal current, the sector
limit is 88 degrees.
There is no sector rounding on the other side of the sector.
If the current amplitude falls below one percent of the nominal current, the
direction enters the non-directional area.
Min forward angle
Non-operating area
88 deg
Max reverse angle
1% nominal
amplitude
20% nominal
amplitude
100% nominal
amplitude
Figure 72: Operating characteristic for phase angle classic 88
-V
0
RCA
I
0
1MAC309294-MB F
Max forward angle
88 deg
Min reverse angle
RER620
Technical Manual