16.8.10.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Zero sequence overcurrent protection
LCZSPTOC - 51N
16.8.10.2 Application
Zero sequence symmetrical components are present in all abnormal conditions involving
ground. They are having a considerably high value during ground faults.
Zero sequence overcurrent protection (LCZSPTOC, 51N) is a definite time stage
comparator function. The zero sequence input current from the SMAI block is connected
as input to the function through a group connection I3P in PCM600. This current is
compared against the preset value and a pickup signal will be set high if the input zero
sequence current is more than the preset value 3I0> PU. Trip signal will be set high after
a time delay setting of t3I0. BLOCK input will block the complete function. BLKTR will
block the trip output. Zero sequence current is available as service value output 3I0.
16.8.10.3 Setting guidelines
GlobalBaseSel: Selects the global base value group used by the function to define IBase,
VBase and SBase as applicable.
3I0 PU : Level of high zero sequence current detection given in % of IBase. This setting
should be based on fault calculations to find the zero sequence current in case of a fault at
the most remote point where the direct trip scheme shall be active. The zero sequence
current shall be calculated for different types of faults (single phase to ground and phase
to phase to ground) at different switching states in the network.
t3I0: Time delay for trip in case of high zero sequence current detection. The trip function
can be used as stand alone short circuit protection with a long time delay. The choice of
time delay is depending on the application of the protection as well as network topology.
16.8.11 Three phase overcurrent LCP3PTOC (51)
16.8.11.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Three phase overcurrent
LCP3PTOC - 51
1MRK 506 369-UUS - Section 16
Scheme communication
Line distance protection REL670 2.2 ANSI 787
Application manual
To Next Page
Loading...
