ABB RELION REX640 Technical Manual page 469

1MRS759142 C
REX640
Technical Manual
EFPADM supports a wide range of different characteristics to achieve the maximum
flexibility and sensitivity in different applications. The basic characteristic shape is
selected with the Operation mode and Directional mode settings. Operation mode
defines which operation criterion or criteria are enabled and Directional mode defines
if the forward, reverse or non-directional boundary lines for that particular operation
mode are activated. The FAULT_DIR output indicates which operation sector the
fault is measured. The output is operational once the function is started.
Table 512: Operation criteria
Operation mode
Yo
Bo
Go
Yo, Go
Yo, Bo
Go, Bo
Yo, Go, Bo
The options for the Directional mode setting are "Non-directional", "Forward" and
"Reverse".
Figure 249, Figure 250
supported by EFPADM and the settings relevant to that particular characteristic. The
most typical characteristics are highlighted and explained in details in the chapter
Neutral admittance characteristics. Operation is achieved when the calculated neutral
admittance Yo moves outside the characteristic (the operation area is marked with
gray).
The settings defining the admittance characteristics are given in
primary milliSiemens (mS). The conversion equation for the
admittance from secondary to primary is:
Y Y
=
pri sec
GUID-54838334-2E4D-4DAB-BE08-994FB4C0A8A9 V1 EN
ni CT ratio for the residual current Io
CT
nu VT ratio for the residual voltage Uo
VT
Example: Admittance setting in the secondary is 5.00 milliSiemens.
The CT ratio is 100/1 A and the VT ratio is 11547/100 V. The
admittance setting in the primary can be calculated.
Description
Admittance criterion
Susceptance criterion
Conductance criterion
Admittance criterion combined with the
conductance criterion
Admittance criterion combined with the
susceptance criterion
Conductance criterion combined with the
susceptance criterion
Admittance criterion combined with the
conductance and susceptance criterion
and Figure 251 illustrate the admittance characteristics
ni
CT
⋅
nu
VT
Section 4
Protection functions
(Equation 57)
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