Toshiba GR200 Series Instruction Manual page 65

where,
I1 0 : Current in zero-sequence flowing at the local terminal1
I2 0 : Current in zero-sequence flowing at the remote terminal2
I3 0 : Current in zero-sequence flowing at the other remote terminal3
I d0
Figure 2.3-1 Zero-sequence current differential element (I r0 -I d0 Plane for DIFGL)
The DIFGL characteristic is identical to the DIFL characteristic for which is defined in
the small current region. The DIFGL characteristic is expressed using the following equations:
The user should set a minimum residual current for setting [DIFGL-I] for the occurrence
of a fault. The user should also set slope characteristic for setting [DIFGL-Slope].
Inflow current (I in ) and Outflow current (I out ) plain for DIFGL function
(ii)
Figure 2.3-2 provides another expression corresponding to the Figure 2.3-1 characteristic; the
user can notice that the characteristic is expressed on the plane between the outflowing current
(I out ) axis and inflow current (I in ) axis. The element of the DIFGL function operates for the
hatched area on the I out –I in plain.
= | I1 | + | I2
I
r0 0
Z
o
I ≥ γ × ��
d0
Z = ( 1 − γ ) × setting [DIFGL-I]
setting [DIFGL-Slope]
γ =
- 42 -
| + | I3 |
0 0
Operating Zone
[DIFGL-Slope]
I r0
+ ��
��0
100
6F2S1914 (0.49)
(2.3-2)
(2.3-3)
(2.3-4)
(2.3-5)
GRL200 (Soft 033 & 037)