Toshiba GR200 Series - (vii) Block of issuing a trip signal; (viii) Specializing in micro earth faults

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 45 -
(vii) Block of issuing a trip signal
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.
(viii) Specializing in micro earth faults
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:











(2.3-7)
where,
Σ|I
01
|: Scalar summation of zero-sequence phase current at the local-terminal
Σ|I
02
|: Scalar summation of zero-sequence phase current at the remote-terminal
pu: per unit value