Toshiba GR-200 Series Instruction Manual page 301

Voltage condition and check zone
2.25.1
To provide the voltage and synchronism check schemes, the VCHK function has the following
relay elements: OVB, OVL, UVB, and UVL. The OVB and OVL elements are used to verify the
presence of voltage on the busbar and the line respectively, whereas the UVB and UVL
elements are used to verify the absence of voltage on the busbar and the line respectively.
Figure 2.25-2 illustrates the four zones used (A1 to D1) to verify the presence or the
absence of the above voltages. For example, as shown in Figure 2.25-2, when reclosing of CB
on the line is required, the voltage condition on the busbar G (i.e., running voltage) should be
examined prior to reclosing. Thus, if the OVB element
operates, the VCHK function is able to output the permissive signal. Incidentally, if the voltage
condition coincides with the B1 zone, the synchronism check scheme is ready to start within
the VCHK function. In addition, note that the synchronism check scheme is not required for
zones A1, C1 or D1.
Setting [VCHK-OVL]
Setting [VCHK-UVL]
Figure 2.25-2 Four check zones examined in the VCHK function
Table 2.25-1 Four voltage conditions and zones
Voltage condition
Check zone
○
B usbar voltage
(V B =Running voltage)
○
L ine voltage
(V L =Incoming voltage)
Synchronism check
V L Line voltage
(Incoming voltage)
Dead bus and
live line
A1
(DB_LL)
Dead bus and
dead line
(DB_DL)
C1
0(V)
D○
_L○
B L
A1
Dead
Live
N.A.
- 282 -
operates and the UVL element
(G)
Live bus and
live line
B1
(LB_LL)
Live bus and
dead line
(LB_DL)
D1
V B Busbar voltage
(Running voltage)
L○ D○
_L○ _D○
B L B L
B1 C1
Live Dead
Live Dead
Applicable N.A.
6F2T0200 (0.15)
(G)
(G)
L○
_D○
B L
D1
Live
Dead
N.A.
GRE200 (1,2)