ABB RER615 - Page 351

Table 378: Operation criteria
Operation mode Description
Yo Admittance criterion
Bo Susceptance criterion
Go Conductance criterion
Yo, Go Admittance criterion combined with the con-
ductance criterion
Yo, Bo Admittance criterion combined with the sus-
ceptance criterion
Go, Bo Conductance criterion combined with the
susceptance criterion
Yo, Go, Bo Admittance criterion combined with the con-
ductance and susceptance criterion
The options for the Directional mode setting are "Non-directional", "Forward" and
"Reverse".
Figure 168 , Figure 169 and Figure 170 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 4.2.4.5 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 23)
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 milliSiemens
A
V
milliSiemens
pri
= ⋅ =5 00
100 1
11547 100
4 33. .
(Equation 24)
1MRS758755 C
Protection functions
REC615 & RER615
Technical Manual
351