ABB RELION REX640 Technical Manual page 869

1MRS759142 C
REX640
Technical Manual
General Fault Criteria (GFC)
Earth-fault detection function
Directional function for earth faults
Fault loop selection and back-up protection
Cross-country fault detection function for
high-impedance earthed networks
Phase preference logic for high-impedance
earthed networks
Fault loop selection logic for low-impedance
earthed networks
GUID-D80CFBCA-BD57-4933-9F0A-F138F235E55A V1 EN
Figure 466: Main functionality of DSTPDIS
All outputs and the operation of all sub-functions can be blocked with the BLOCK
binary input signal. In addition, it resets the timers.
Blocking
There are three operation modes in the blocking function. The operation modes are
controlled by the BLOCK input and the global setting in Configuration/System/
Blocking mode which selects the blocking mode. The BLOCK input can be controlled
by a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode,
the operation timer is frozen to the prevailing value, but the OPERATE_Z1...5
output is not deactivated when blocking is activated. In the "Block all" mode, the
whole function is blocked and the timers are reset. In the "Block OPERATE output"
mode, the function operates normally but the OPERATE_Z1...5 output is not
activated.
In addition, the function has zone-specific blocking signals BLOCK_Z1...5. The
signal resets zone timers disabling the corresponding start and operate output
activation.
BLOCK_GFC deactivates START_GFC and OPERATE_GFC. It also resets GFC
operate time (set by Operate delay GFC). Blocking does not prevent GFC operation.
Earth-fault detection function
The recognition of an earth fault is an important part in identifying the correct fault
type. This information is used in faulted loop (phase) selection to release the correct
impedance-measuring elements. The earth-fault recognition is always required to
release the phase-to-earth impedance-measuring elements.
Section 4
Protection functions
Zone Z1
Zone Z2
Zone Z3
Zone Z4
Zone Z5
863