Toshiba GR200 Series Instruction Manual page 68

Block of issuing a trip signal
(vii)
If the user does not wish that the DIFGL function issues a trip signal, the user can use PLC
connection point "DIFGL_BLOCK" so that the DIFGL function cannot issue a trip signal when
a block signal enters. The PLC connection point "DIFGL_BLOCK" is also shown in Figure
2.3-3; the one is useful when a user-made-program is required to instruct to block externally.
Specializing in micro earth faults
(viii)
Since the DIFGL is used for high-impedance earth fault protection, a DIFGL output signal is
blocked when zero-sequence phase current is true of the following equation:
where,
Σ|I |: Scalar summation of zero-sequence phase current at the local-terminal
01
Σ|I |: Scalar summation of zero-sequence phase current at the remote-terminal
02
pu: per unit value
∑ | I | ≥ 2pu or ∑ | I
01 02
- 45 -
| ≥ 2pu
GRL200 (Soft 033 & 037)
6F2S1914 (0.49)
(2.3-7)