ABB REL650 series, Applications Manual, Page: 155 / 516

2
min
V
Zload
S
=
EQUATION1753-ANSI V1 EN
(Equation 69)
Where:
V
is the minimum phase-to-phase voltage in kV
S is the maximum apparent power in MVA.
The load angle LdAngle can be derived according to equation 70 :
max
cos
max
P
LdAngle a
S
æ ö
=
ç ÷
è ø
EQUATION1623-ANSI V1 EN
(Equation 70)
where:
Pmax
is the maximal active power transfer during emergency conditions and
Smax is the maximal apparent power transfer during emergency conditions.
The RLd can be calculated according to equation 71 :
cos( ) RLd ZLoad LdAngle
= ×
EQUATION1624-ANSI V1 EN
(Equation 71)
The setting of RLd and LdAngle is by default set to 80 ohm/phase and 20 degrees. Those
values must be adapted to the specific application.
6.4 Additional distance protection directional function for
ground faults ZDARDIR (21D)
6.4.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Additional distance protection
directional function for ground faults
ZDARDIR
S00346 V1 EN
21D
1MRK 506 334-UUS A
Section 6
Impedance protection
149
Application manual