Toshiba GR 200 Series, Instruction Manual

Page: 400 / 1563

6F2S1915 (0.46)
GRZ200 (Soft 031 & 032)
- 379 -
2.25.1
VCHK1 for 1CB system
(i)
Characteristic and elements
VCHK1 does voltage and synchronous check in 1CB system. Four relay elements (OVB, OVB,
UVL, and UVL) are used for voltage check. Tow relay elements (OVB and OVL) are used for
verification of existing voltage; the remaining ones (UVB and UVL) are used for verification of
non-existing voltage.
(ii)
Voltage condition and check zone
Figure 2.25-2 shows four zones (A1 to D1) for voltage verification. For example, if both UVB
and OVL elements are active, VHCK1 determines that the Bus-bar is in Dead condition (no-
voltage) and Line is in Live condition (existing voltage). This condition holds true for A1 zone.
If voltage condition matches with B1 zone, synchronous check is carried out on VCHK1. Thus,
this means that Synchronous check is not carried out in A1, C1 or D1 zones.
C1 D1
B1 A1
0(V)
VCHK-UVL
VCHK-OVL
A1, C1, D1: Voltage check
B1: Synchronism check
VCHK-UVB VCHK-OVB
VL Line voltage
(Incoming voltage)
VB Bus-bar voltage
(Running voltage)
Dead bus and
dead line
(DB-DL)
Dead bus and
live line
(DB-LL) Live bus and
live line
(LB-LL)
Live bus and
dead line
(LB-DL)
Figure 2.25-2 Check zones by VCHK1
Table 2.25-2 Voltage condition by VCHK1
Voltage condition DB_LL LB_LL DB_DL LB_DL
Check zone A1 B1 C1 D1
Bus-bar voltage (VB)
Dead Live Dead Live
Line voltage (VL)
Live Live Dead Dead