ABB REB670 Applications Manual page 286

Section 11
Secondary system supervision
280
The settings Vdif Main block, Vdif Pilot alarm and VSealIn are in percentage of the base
voltage, VBase. Set VBase to the primary rated phase-to-phase voltage of the potential
voltage transformer. VBase is available in the Global Base Value groups; the particular
Global Base Value group, that is used by VDSPVC (60), is set by the setting parameter
GlobalBaseSel.
The settings Vdif Main block and Vdif Pilot alarm should be set low (approximately 30%
of VBase) so that they are sensitive to the fault on the voltage measurement circuit, since
the voltage on both sides are equal in the healthy condition. If V
up primary phase-to-phase voltage of measured fuse group, the setting of Vdif Main block
and Vdif Pilot alarm will be given according to equation 94.
Vdif Main block or Vdif Pilot alarm=
ANSI13000279 V1 EN
V is defined as phase to neutral or phase to phase voltage dependent of the selected
SetPrim
ConTypeMain and ConTypePilot. If ConTypeMain and ConTypePilot are set to Ph-N than
the function performs internally the rescaling of V
When SealIn is set to On and the fuse failure has last for more than 5 seconds, the blocked
protection functions will remain blocked until normal voltage conditions are restored
above the VSealIn setting. The fuse failure outputs are deactivated when the normal
voltage conditions are restored.
V
SetPrim
⋅100
V
Base
.
SetPrim
1MRK 505 337-UUS -
is the desired pick
SetPrim
(Equation 94)
Application manual