- For Neutral Current (N) Inject 3 Phase Current with same magnitude and same phase angles. So, IN = IR + IB + IY = 0.5 (0 O) + 1.0 (240 O) + 1.5 (120 O) = 0.866 (150 O) Applied Current Display secondary %Error Phase Magnitude Angle Magnitude Angle Magnitude Angle R 0.5 0.0 Y 1.0 240.0 B 1.50 120.0 N -- -- MEASUREMENTS (LOCAL / REMOTE) Applied CURRENT Display Primary LDCM Value Phase Magnitude Angle Magnitude Angle Magnitude Angle R 1.0 0.0 Y 1.0 240.0 B 1.0 120.0 Limits: Amplitude Accuracy; ± 0.5 % Ir According to the Catalogue for Technical Data – Page: 32 PICK UP & DROP OFF TEST FOR DIFFERENTIAL CURRENT (ID) : Use fiber optic communication between ch1& ch2 then test of differential protection element; Also, charge current should be not active in the setting. Pick Up Value = Idmin A Setting Injected Current Measured Pick Measured Drop Phase Idmin (A) I bias (A) Up Value (A) Out Value (A)
- For Neutral Current (N) Inject 3 Phase Current with same magnitude and same phase angles. So, IN = IR + IB + IY = 0.5 (0 O) + 1.0 (240 O) + 1.5 (120 O) = 0.866 (150 O) Phase Applied Current Display secondary %Error Magnitude Angle Magnitude Angle Magnitude Angle R 0.5 0.0 Y 1.0 240.0 B 1.50 120.0 N -- -- MEASUREMENTS (LOCAL / REMOTE) Phase Applied CURRENT Display Primary LDCM Value Magnitude Angle Magnitude Angle Magnitude Angle R 1.0 0.0 Y 1.0 240.0 B 1.0 120.0 Limits: Amplitude Accuracy; ± 0.5 % Ir According to the Catalogue for Technical Data – Page: 32 PICK UP & DROP OFF TEST FOR DIFFERENTIAL CURRENT (ID) : Use fiber optic communication between ch1& ch2 then test of differential protection element; Also, charge current should be not active in the setting. Pick Up Value = Idmin A Phase Setting Idmin (A) Injected Current I bias (A) Measured Pick Up Value (A) Measured Drop Out Value (A)