ABB REC650 Applications Manual page 132

Section 6
Current protection
126
ANSI06000652 V2 EN
Figure 56: Characteristic for RCADir = 0° and ROADir = 80°
DirMode is set Forward or Reverse to set the direction of the trip function from the
directional residual current function.
All the directional protection modes have a residual current release level setting INRelPU
which is set in % of IBase. This setting should be chosen smaller than or equal to the lowest
fault current to be detected.
All the directional protection modes have a residual voltage release level setting VNRelPU
which is set in % of VBase. This setting should be chosen smaller than or equal to the
lowest fault residual voltage to be detected.
tDef is the definite time delay, given in s, for the directional residual current protection if
definite time delay is chosen.
The characteristic angle of the directional functions RCADir is set in degrees. RCADir is
normally set equal to 0° in a high impedance grounded network with a neutral point
resistor as the active current component is appearing out on the faulted feeder only.
RCADir is set equal to -90° in an isolated network as all currents are mainly capacitive.
The relay open angle ROADir is set in degrees. For angles differing more than ROADir
fromRCADir the function from the protection is blocked. The setting can be used to
prevent unwanted function for non-faulted feeders, with large capacitive ground-fault
current contributions, due to CT phase angle error.
RCA = 0º
ROA = 80º
Operate area
3I
0
V =-3V
ref
ANSI06000652-2-en.vsd
1MRK 511 286-UUS A
0
Application manual