ABB RELION REX640, Technical Manual, Page: 499 / 1960

Table 566: Operation criteria
Operation mode Description
Yo Admittance criterion
Bo Susceptance criterion
Go Conductance criterion
Yo, Go Admittance criterion combined with the conductance criteri-
on
Yo, Bo Admittance criterion combined with the susceptance criteri-
on
Go, Bo Conductance criterion combined with the susceptance crite-
rion
Yo, Go, Bo Admittance criterion combined with the conductance and
susceptance criterion
The options for the
Directional mode setting are "Non-directional", "Forward" and
"Reverse".
Figure 282
,
Figure 283
and
Figure 284
illustrate the admittance characteristics
supported by EFPADM and the settings relevant to that particular characteristic.
The most typical characteristics are highlighted and explained in details in
Chapter 4.2.4.6 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
ni
nu
pri
CT
VT
= ⋅
sec
(Equation 69)
ni
CT
CT ratio for the residual current Io
nu
VT
VT ratio for the residual voltage Uo
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.
Y mS
A
V
mS
pri
= ⋅ =
5 00
100
1
11547
100
4 33 . .
(Equation 70)
1MRS759142 F Protection functions
REX640
Technical Manual
499