Table of Contents
Advertisement
116
Scheme communication logic for residual
overcurrent protection (EFC)
EFC-BLOCK
EFC-CR
EFC-CACC
EFC-CSBLK
EFC-CSPRM
)LJXUH 6LPSOLILHG ORJLF GLDJUDP 6FKHPH W\SH
'HVLJQ
%ORFNLQJ VFKHPH
In the blocking scheme, a signal is sent to the other line end if the directional element
in TEF function, connected to the EFC--CSBLK input signal, detects a fault in the re-
verse direction. When the forward directional element operates, it trips the line after a
short time delay if no blocking signal is received from the other line end. The time de-
lay, normally 30-40 ms, depends on the communication transmission time and the cho-
sen safety margin.
3HUPLVVLYH RYHUUHDFKLQJ VFKHPH
In the permissive scheme, the forward direction measuring element in TEF function,
connected to the EFC--CSPRM input, sends a permissive signal to the other line end if
a fault is detected in the forward direction. The directional element at the other line end
must wait for a permissive signal before giving a trip signal. Independent channels (fre-
quencies) must be available for the communication in each direction.
&DOFXODWLRQV
6HWWLQJ
The parameters for the scheme communication logic for residual overcurrent protection
function are set via the local HMI or PST (Parameter Setting Tool). Refer to the Tech-
nical reference manual for setting parameters and path in local HMI.
&
&
0-60 s
&
t
t Coord
&
&
&KDSWHU
EFC-CRL
25 ms
EFC-TRIP
t
50 ms
t
>1
99000108.vsd
SHUPLVVLYH
&XUUHQW
EFC-CS
Advertisement
Table of Contents
